8388 lines
224 KiB
Diff
8388 lines
224 KiB
Diff
From 89067d28ca90681fc6cf108de79b9aedb93dfa9d Mon Sep 17 00:00:00 2001
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From: Tk-Glitch <ti3nou@gmail.com>
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Date: Mon, 25 Nov 2019 21:46:23 +0100
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Subject: PDS 099o, 5.4 rebase
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diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
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index 032c7cd3cede..360a229b0abe 100644
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--- a/Documentation/admin-guide/sysctl/kernel.rst
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+++ b/Documentation/admin-guide/sysctl/kernel.rst
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@@ -82,6 +82,7 @@ show up in /proc/sys/kernel:
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- randomize_va_space
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- real-root-dev ==> Documentation/admin-guide/initrd.rst
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- reboot-cmd [ SPARC only ]
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+- rr_interval
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- rtsig-max
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- rtsig-nr
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- sched_energy_aware
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@@ -105,6 +106,7 @@ show up in /proc/sys/kernel:
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- unknown_nmi_panic
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- watchdog
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- watchdog_thresh
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+- yield_type
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- version
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diff --git a/Documentation/scheduler/sched-PDS-mq.txt b/Documentation/scheduler/sched-PDS-mq.txt
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new file mode 100644
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index 000000000000..709e86f6487e
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--- /dev/null
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+++ b/Documentation/scheduler/sched-PDS-mq.txt
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@@ -0,0 +1,56 @@
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+ Priority and Deadline based Skiplist multiple queue Scheduler
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+ -------------------------------------------------------------
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+
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+CONTENT
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+========
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+
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+ 0. Development
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+ 1. Overview
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+ 1.1 Design goal
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+ 1.2 Design summary
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+ 2. Design Detail
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+ 2.1 Skip list implementation
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+ 2.2 Task preempt
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+ 2.3 Task policy, priority and deadline
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+ 2.4 Task selection
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+ 2.5 Run queue balance
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+ 2.6 Task migration
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+
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+
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+0. Development
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+==============
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+
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+Priority and Deadline based Skiplist multiple queue scheduler, referred to as
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+PDS from here on, is developed upon the enhancement patchset VRQ(Variable Run
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+Queue) for BFS(Brain Fuck Scheduler by Con Kolivas). PDS inherits the existing
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+design from VRQ and inspired by the introduction of skiplist data structure
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+to the scheduler by Con Kolivas. However, PDS is different from MuQSS(Multiple
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+Queue Skiplist Scheduler, the successor after BFS) in many ways.
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+
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+1. Overview
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+===========
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+
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+1.1 Design goal
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+---------------
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+
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+PDS is designed to make the cpu process scheduler code to be simple, but while
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+efficiency and scalable. Be Simple, the scheduler code will be easy to be read
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+and the behavious of scheduler will be easy to predict. Be efficiency, the
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+scheduler shall be well balance the thoughput performance and task interactivity
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+at the same time for different properties the tasks behave. Be scalable, the
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+performance of the scheduler should be in good shape with the glowing of
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+workload or with the growing of the cpu numbers.
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+
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+1.2 Design summary
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+------------------
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+
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+PDS is described as a multiple run queues cpu scheduler. Each cpu has its own
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+run queue. A heavry customized skiplist is used as the backend data structure
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+of the cpu run queue. Tasks in run queue is sorted by priority then virtual
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+deadline(simplfy to just deadline from here on). In PDS, balance action among
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+run queues are kept as less as possible to reduce the migration cost. Cpumask
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+data structure is widely used in cpu affinity checking and cpu preemption/
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+selection to make PDS scalable with increasing cpu number.
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+
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+
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+To be continued...
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diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
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index f18d5067cd0f..fe489fc01c73 100644
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--- a/arch/powerpc/platforms/cell/spufs/sched.c
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+++ b/arch/powerpc/platforms/cell/spufs/sched.c
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@@ -51,11 +51,6 @@ static struct task_struct *spusched_task;
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static struct timer_list spusched_timer;
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static struct timer_list spuloadavg_timer;
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-/*
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- * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
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- */
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-#define NORMAL_PRIO 120
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-
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/*
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* Frequency of the spu scheduler tick. By default we do one SPU scheduler
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* tick for every 10 CPU scheduler ticks.
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diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
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index 8ef85139553f..9d44d8d78259 100644
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--- a/arch/x86/Kconfig
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+++ b/arch/x86/Kconfig
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@@ -1034,6 +1034,22 @@ config NR_CPUS
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config SCHED_SMT
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def_bool y if SMP
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+config SMT_NICE
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+ bool "SMT (Hyperthreading) aware nice priority and policy support"
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+ depends on SCHED_PDS && SCHED_SMT
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+ default y
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+ ---help---
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+ Enabling Hyperthreading on Intel CPUs decreases the effectiveness
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+ of the use of 'nice' levels and different scheduling policies
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+ (e.g. realtime) due to sharing of CPU power between hyperthreads.
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+ SMT nice support makes each logical CPU aware of what is running on
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+ its hyperthread siblings, maintaining appropriate distribution of
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+ CPU according to nice levels and scheduling policies at the expense
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+ of slightly increased overhead.
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+
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+ If unsure say Y here.
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+
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+
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config SCHED_MC
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def_bool y
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prompt "Multi-core scheduler support"
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diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
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index b66e81c06a57..a294f8f5fd75 100644
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--- a/drivers/cpufreq/cpufreq_conservative.c
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+++ b/drivers/cpufreq/cpufreq_conservative.c
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@@ -28,8 +28,8 @@ struct cs_dbs_tuners {
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};
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/* Conservative governor macros */
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-#define DEF_FREQUENCY_UP_THRESHOLD (80)
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-#define DEF_FREQUENCY_DOWN_THRESHOLD (20)
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+#define DEF_FREQUENCY_UP_THRESHOLD (63)
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+#define DEF_FREQUENCY_DOWN_THRESHOLD (26)
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#define DEF_FREQUENCY_STEP (5)
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#define DEF_SAMPLING_DOWN_FACTOR (1)
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#define MAX_SAMPLING_DOWN_FACTOR (10)
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diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c
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index dced033875bf..d2cd03766b09 100644
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--- a/drivers/cpufreq/cpufreq_ondemand.c
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+++ b/drivers/cpufreq/cpufreq_ondemand.c
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@@ -18,7 +18,7 @@
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#include "cpufreq_ondemand.h"
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/* On-demand governor macros */
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-#define DEF_FREQUENCY_UP_THRESHOLD (80)
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+#define DEF_FREQUENCY_UP_THRESHOLD (63)
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#define DEF_SAMPLING_DOWN_FACTOR (1)
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#define MAX_SAMPLING_DOWN_FACTOR (100000)
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#define MICRO_FREQUENCY_UP_THRESHOLD (95)
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@@ -127,7 +127,7 @@ static void dbs_freq_increase(struct cpufreq_policy *policy, unsigned int freq)
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}
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/*
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- * Every sampling_rate, we check, if current idle time is less than 20%
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+ * Every sampling_rate, we check, if current idle time is less than 37%
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* (default), then we try to increase frequency. Else, we adjust the frequency
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* proportional to load.
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*/
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diff --git a/fs/proc/base.c b/fs/proc/base.c
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index ebea9501afb8..51c9346a69fe 100644
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--- a/fs/proc/base.c
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+++ b/fs/proc/base.c
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@@ -477,7 +477,7 @@ static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
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seq_puts(m, "0 0 0\n");
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else
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seq_printf(m, "%llu %llu %lu\n",
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- (unsigned long long)task->se.sum_exec_runtime,
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+ (unsigned long long)tsk_seruntime(task),
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(unsigned long long)task->sched_info.run_delay,
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task->sched_info.pcount);
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diff --git a/include/linux/init_task.h b/include/linux/init_task.h
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index 2c620d7ac432..1a7987c40c80 100644
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--- a/include/linux/init_task.h
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+++ b/include/linux/init_task.h
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@@ -36,7 +36,11 @@ extern struct cred init_cred;
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#define INIT_PREV_CPUTIME(x)
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#endif
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+#ifdef CONFIG_SCHED_PDS
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+#define INIT_TASK_COMM "PDS"
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+#else
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#define INIT_TASK_COMM "swapper"
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+#endif /* !CONFIG_SCHED_PDS */
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/* Attach to the init_task data structure for proper alignment */
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#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
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diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
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index 1b6d31da7cbc..dea181bdb1dd 100644
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--- a/include/linux/jiffies.h
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+++ b/include/linux/jiffies.h
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@@ -171,7 +171,7 @@ static inline u64 get_jiffies_64(void)
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* Have the 32 bit jiffies value wrap 5 minutes after boot
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* so jiffies wrap bugs show up earlier.
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*/
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-#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
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+#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-10*HZ))
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/*
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* Change timeval to jiffies, trying to avoid the
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diff --git a/include/linux/sched.h b/include/linux/sched.h
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index 67a1d86981a9..8268cad4b0a2 100644
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--- a/include/linux/sched.h
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+++ b/include/linux/sched.h
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@@ -31,6 +31,7 @@
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#include <linux/task_io_accounting.h>
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#include <linux/posix-timers.h>
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#include <linux/rseq.h>
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+#include <linux/skip_list.h>
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/* task_struct member predeclarations (sorted alphabetically): */
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struct audit_context;
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@@ -644,9 +645,13 @@ struct task_struct {
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unsigned int flags;
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unsigned int ptrace;
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-#ifdef CONFIG_SMP
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+#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_PDS)
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struct llist_node wake_entry;
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+#endif
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+#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_PDS)
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int on_cpu;
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+#endif
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+#ifdef CONFIG_SMP
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#ifdef CONFIG_THREAD_INFO_IN_TASK
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/* Current CPU: */
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unsigned int cpu;
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@@ -655,6 +660,7 @@ struct task_struct {
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unsigned long wakee_flip_decay_ts;
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struct task_struct *last_wakee;
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+#ifndef CONFIG_SCHED_PDS
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/*
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* recent_used_cpu is initially set as the last CPU used by a task
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* that wakes affine another task. Waker/wakee relationships can
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@@ -663,6 +669,7 @@ struct task_struct {
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* used CPU that may be idle.
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*/
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int recent_used_cpu;
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+#endif /* CONFIG_SCHED_PDS */
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int wake_cpu;
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#endif
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int on_rq;
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@@ -672,13 +679,27 @@ struct task_struct {
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int normal_prio;
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unsigned int rt_priority;
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+#ifdef CONFIG_SCHED_PDS
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+ int time_slice;
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+ u64 deadline;
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+ /* skip list level */
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+ int sl_level;
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+ /* skip list node */
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+ struct skiplist_node sl_node;
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+ /* 8bits prio and 56bits deadline for quick processing */
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+ u64 priodl;
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+ u64 last_ran;
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+ /* sched_clock time spent running */
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+ u64 sched_time;
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+#else /* CONFIG_SCHED_PDS */
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const struct sched_class *sched_class;
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struct sched_entity se;
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struct sched_rt_entity rt;
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+ struct sched_dl_entity dl;
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+#endif
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#ifdef CONFIG_CGROUP_SCHED
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struct task_group *sched_task_group;
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#endif
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- struct sched_dl_entity dl;
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#ifdef CONFIG_UCLAMP_TASK
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/* Clamp values requested for a scheduling entity */
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@@ -1283,6 +1304,29 @@ struct task_struct {
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*/
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};
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+#ifdef CONFIG_SCHED_PDS
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+void cpu_scaling(int cpu);
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+void cpu_nonscaling(int cpu);
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+#define tsk_seruntime(t) ((t)->sched_time)
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+/* replace the uncertian rt_timeout with 0UL */
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+#define tsk_rttimeout(t) (0UL)
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+
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+#define task_running_idle(p) ((p)->prio == IDLE_PRIO)
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+#else /* CFS */
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+extern int runqueue_is_locked(int cpu);
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+static inline void cpu_scaling(int cpu)
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+{
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+}
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+
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+static inline void cpu_nonscaling(int cpu)
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+{
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+}
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+#define tsk_seruntime(t) ((t)->se.sum_exec_runtime)
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+#define tsk_rttimeout(t) ((t)->rt.timeout)
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+
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+#define iso_task(p) (false)
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+#endif /* CONFIG_SCHED_PDS */
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+
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static inline struct pid *task_pid(struct task_struct *task)
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{
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return task->thread_pid;
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diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h
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index 1aff00b65f3c..a5e5fc2c9170 100644
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--- a/include/linux/sched/deadline.h
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+++ b/include/linux/sched/deadline.h
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@@ -1,5 +1,22 @@
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/* SPDX-License-Identifier: GPL-2.0 */
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+#ifdef CONFIG_SCHED_PDS
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+
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+#define __tsk_deadline(p) ((p)->deadline)
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+
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+static inline int dl_prio(int prio)
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+{
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+ return 1;
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+}
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+
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+static inline int dl_task(struct task_struct *p)
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+{
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+ return 1;
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+}
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+#else
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+
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+#define __tsk_deadline(p) ((p)->dl.deadline)
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+
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/*
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* SCHED_DEADLINE tasks has negative priorities, reflecting
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* the fact that any of them has higher prio than RT and
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@@ -19,6 +36,7 @@ static inline int dl_task(struct task_struct *p)
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{
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return dl_prio(p->prio);
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}
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+#endif /* CONFIG_SCHED_PDS */
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static inline bool dl_time_before(u64 a, u64 b)
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{
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diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
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index 7d64feafc408..fba04bb91492 100644
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--- a/include/linux/sched/prio.h
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+++ b/include/linux/sched/prio.h
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@@ -20,7 +20,18 @@
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*/
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#define MAX_USER_RT_PRIO 100
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+
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+#ifdef CONFIG_SCHED_PDS
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+#define ISO_PRIO (MAX_USER_RT_PRIO)
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+
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+#define MAX_RT_PRIO ((MAX_USER_RT_PRIO) + 1)
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+
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+#define NORMAL_PRIO (MAX_RT_PRIO)
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+#define IDLE_PRIO ((MAX_RT_PRIO) + 1)
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+#define PRIO_LIMIT ((IDLE_PRIO) + 1)
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+#else /* !CONFIG_SCHED_PDS */
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#define MAX_RT_PRIO MAX_USER_RT_PRIO
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+#endif /* CONFIG_SCHED_PDS */
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#define MAX_PRIO (MAX_RT_PRIO + NICE_WIDTH)
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#define DEFAULT_PRIO (MAX_RT_PRIO + NICE_WIDTH / 2)
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diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h
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index e5af028c08b4..a96012e6f15e 100644
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--- a/include/linux/sched/rt.h
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+++ b/include/linux/sched/rt.h
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@@ -24,8 +24,10 @@ static inline bool task_is_realtime(struct task_struct *tsk)
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if (policy == SCHED_FIFO || policy == SCHED_RR)
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return true;
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+#ifndef CONFIG_SCHED_PDS
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if (policy == SCHED_DEADLINE)
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return true;
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+#endif
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return false;
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}
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diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h
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index 4b1c3b664f51..f186b8119ad6 100644
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--- a/include/linux/sched/task.h
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+++ b/include/linux/sched/task.h
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@@ -99,7 +99,7 @@ extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
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extern void free_task(struct task_struct *tsk);
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/* sched_exec is called by processes performing an exec */
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-#ifdef CONFIG_SMP
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+#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_PDS)
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extern void sched_exec(void);
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#else
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#define sched_exec() {}
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diff --git a/include/linux/skip_list.h b/include/linux/skip_list.h
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new file mode 100644
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index 000000000000..713fedd8034f
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--- /dev/null
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+++ b/include/linux/skip_list.h
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@@ -0,0 +1,177 @@
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+/*
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+ Copyright (C) 2016 Alfred Chen.
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+
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+ Code based on Con Kolivas's skip list implementation for BFS, and
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+ which is based on example originally by William Pugh.
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+
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+Skip Lists are a probabilistic alternative to balanced trees, as
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+described in the June 1990 issue of CACM and were invented by
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+William Pugh in 1987.
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+
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+A couple of comments about this implementation:
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+
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+This file only provides a infrastructure of skip list.
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+
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+skiplist_node is embedded into container data structure, to get rid the
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+dependency of kmalloc/kfree operation in scheduler code.
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+
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+A customized search function should be defined using DEFINE_SKIPLIST_INSERT
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+macro and be used for skip list insert operation.
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+
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+Random Level is also not defined in this file, instead, it should be customized
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+implemented and set to node->level then pass to the customized skiplist_insert
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+function.
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+
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+Levels start at zero and go up to (NUM_SKIPLIST_LEVEL -1)
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+
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+NUM_SKIPLIST_LEVEL in this implementation is 8 instead of origin 16,
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+considering that there will be 256 entries to enable the top level when using
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+random level p=0.5, and that number is more than enough for a run queue usage
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+in a scheduler usage. And it also help to reduce the memory usage of the
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+embedded skip list node in task_struct to about 50%.
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+
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+The insertion routine has been implemented so as to use the
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+dirty hack described in the CACM paper: if a random level is
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+generated that is more than the current maximum level, the
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+current maximum level plus one is used instead.
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+
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+BFS Notes: In this implementation of skiplists, there are bidirectional
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+next/prev pointers and the insert function returns a pointer to the actual
|
|
+node the value is stored. The key here is chosen by the scheduler so as to
|
|
+sort tasks according to the priority list requirements and is no longer used
|
|
+by the scheduler after insertion. The scheduler lookup, however, occurs in
|
|
+O(1) time because it is always the first item in the level 0 linked list.
|
|
+Since the task struct stores a copy of the node pointer upon skiplist_insert,
|
|
+it can also remove it much faster than the original implementation with the
|
|
+aid of prev<->next pointer manipulation and no searching.
|
|
+*/
|
|
+#ifndef _LINUX_SKIP_LIST_H
|
|
+#define _LINUX_SKIP_LIST_H
|
|
+
|
|
+#include <linux/kernel.h>
|
|
+
|
|
+#define NUM_SKIPLIST_LEVEL (8)
|
|
+
|
|
+struct skiplist_node {
|
|
+ int level; /* Levels in this node */
|
|
+ struct skiplist_node *next[NUM_SKIPLIST_LEVEL];
|
|
+ struct skiplist_node *prev[NUM_SKIPLIST_LEVEL];
|
|
+};
|
|
+
|
|
+#define SKIPLIST_NODE_INIT(name) { 0,\
|
|
+ {&name, &name, &name, &name,\
|
|
+ &name, &name, &name, &name},\
|
|
+ {&name, &name, &name, &name,\
|
|
+ &name, &name, &name, &name},\
|
|
+ }
|
|
+
|
|
+static inline void INIT_SKIPLIST_NODE(struct skiplist_node *node)
|
|
+{
|
|
+ /* only level 0 ->next matters in skiplist_empty()*/
|
|
+ WRITE_ONCE(node->next[0], node);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * FULL_INIT_SKIPLIST_NODE -- fully init a skiplist_node, expecially for header
|
|
+ * @node: the skip list node to be inited.
|
|
+ */
|
|
+static inline void FULL_INIT_SKIPLIST_NODE(struct skiplist_node *node)
|
|
+{
|
|
+ int i;
|
|
+
|
|
+ node->level = 0;
|
|
+ for (i = 0; i < NUM_SKIPLIST_LEVEL; i++) {
|
|
+ WRITE_ONCE(node->next[i], node);
|
|
+ node->prev[i] = node;
|
|
+ }
|
|
+}
|
|
+
|
|
+/**
|
|
+ * skiplist_empty - test whether a skip list is empty
|
|
+ * @head: the skip list to test.
|
|
+ */
|
|
+static inline int skiplist_empty(const struct skiplist_node *head)
|
|
+{
|
|
+ return READ_ONCE(head->next[0]) == head;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * skiplist_entry - get the struct for this entry
|
|
+ * @ptr: the &struct skiplist_node pointer.
|
|
+ * @type: the type of the struct this is embedded in.
|
|
+ * @member: the name of the skiplist_node within the struct.
|
|
+ */
|
|
+#define skiplist_entry(ptr, type, member) \
|
|
+ container_of(ptr, type, member)
|
|
+
|
|
+/**
|
|
+ * DEFINE_SKIPLIST_INSERT_FUNC -- macro to define a customized skip list insert
|
|
+ * function, which takes two parameters, first one is the header node of the
|
|
+ * skip list, second one is the skip list node to be inserted
|
|
+ * @func_name: the customized skip list insert function name
|
|
+ * @search_func: the search function to be used, which takes two parameters,
|
|
+ * 1st one is the itrator of skiplist_node in the list, the 2nd is the skip list
|
|
+ * node to be inserted, the function should return true if search should be
|
|
+ * continued, otherwise return false.
|
|
+ * Returns 1 if @node is inserted as the first item of skip list at level zero,
|
|
+ * otherwise 0
|
|
+ */
|
|
+#define DEFINE_SKIPLIST_INSERT_FUNC(func_name, search_func)\
|
|
+static inline int func_name(struct skiplist_node *head, struct skiplist_node *node)\
|
|
+{\
|
|
+ struct skiplist_node *update[NUM_SKIPLIST_LEVEL];\
|
|
+ struct skiplist_node *p, *q;\
|
|
+ int k = head->level;\
|
|
+\
|
|
+ p = head;\
|
|
+ do {\
|
|
+ while (q = p->next[k], q != head && search_func(q, node))\
|
|
+ p = q;\
|
|
+ update[k] = p;\
|
|
+ } while (--k >= 0);\
|
|
+\
|
|
+ k = node->level;\
|
|
+ if (unlikely(k > head->level)) {\
|
|
+ node->level = k = ++head->level;\
|
|
+ update[k] = head;\
|
|
+ }\
|
|
+\
|
|
+ do {\
|
|
+ p = update[k];\
|
|
+ q = p->next[k];\
|
|
+ node->next[k] = q;\
|
|
+ p->next[k] = node;\
|
|
+ node->prev[k] = p;\
|
|
+ q->prev[k] = node;\
|
|
+ } while (--k >= 0);\
|
|
+\
|
|
+ return (p == head);\
|
|
+}
|
|
+
|
|
+/**
|
|
+ * skiplist_del_init -- delete skip list node from a skip list and reset it's
|
|
+ * init state
|
|
+ * @head: the header node of the skip list to be deleted from.
|
|
+ * @node: the skip list node to be deleted, the caller need to ensure @node is
|
|
+ * in skip list which @head represent.
|
|
+ * Returns 1 if @node is the first item of skip level at level zero, otherwise 0
|
|
+ */
|
|
+static inline int
|
|
+skiplist_del_init(struct skiplist_node *head, struct skiplist_node *node)
|
|
+{
|
|
+ int l, m = node->level;
|
|
+
|
|
+ for (l = 0; l <= m; l++) {
|
|
+ node->prev[l]->next[l] = node->next[l];
|
|
+ node->next[l]->prev[l] = node->prev[l];
|
|
+ }
|
|
+ if (m == head->level && m > 0) {
|
|
+ while (head->next[m] == head && m > 0)
|
|
+ m--;
|
|
+ head->level = m;
|
|
+ }
|
|
+ INIT_SKIPLIST_NODE(node);
|
|
+
|
|
+ return (node->prev[0] == head);
|
|
+}
|
|
+#endif /* _LINUX_SKIP_LIST_H */
|
|
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
|
|
index 25b4fa00bad1..fc0aabdce15f 100644
|
|
--- a/include/uapi/linux/sched.h
|
|
+++ b/include/uapi/linux/sched.h
|
|
@@ -84,7 +84,10 @@ struct clone_args {
|
|
#define SCHED_FIFO 1
|
|
#define SCHED_RR 2
|
|
#define SCHED_BATCH 3
|
|
-/* SCHED_ISO: reserved but not implemented yet */
|
|
+/* SCHED_ISO: Implemented in BFS/MuQSSPDS only */
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+#define SCHED_ISO 4
|
|
+#endif
|
|
#define SCHED_IDLE 5
|
|
#define SCHED_DEADLINE 6
|
|
|
|
diff --git a/init/Kconfig b/init/Kconfig
|
|
index b4daad2bac23..ee3b9957cf3b 100644
|
|
--- a/init/Kconfig
|
|
+++ b/init/Kconfig
|
|
@@ -73,6 +73,21 @@ config THREAD_INFO_IN_TASK
|
|
|
|
menu "General setup"
|
|
|
|
+config SCHED_PDS
|
|
+ bool "PDS-mq cpu scheduler"
|
|
+ help
|
|
+ The Priority and Deadline based Skip list multiple queue CPU
|
|
+ Scheduler for excellent interactivity and responsiveness on the
|
|
+ desktop and solid scalability on normal hardware and commodity
|
|
+ servers.
|
|
+
|
|
+ Currently incompatible with the Group CPU scheduler, and RCU TORTURE
|
|
+ TEST so these options are disabled.
|
|
+
|
|
+ Say Y here.
|
|
+ default y
|
|
+
|
|
+
|
|
config BROKEN
|
|
bool
|
|
|
|
@@ -802,6 +817,7 @@ config NUMA_BALANCING
|
|
depends on ARCH_SUPPORTS_NUMA_BALANCING
|
|
depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
|
|
depends on SMP && NUMA && MIGRATION
|
|
+ depends on !SCHED_PDS
|
|
help
|
|
This option adds support for automatic NUMA aware memory/task placement.
|
|
The mechanism is quite primitive and is based on migrating memory when
|
|
@@ -903,7 +919,7 @@ menuconfig CGROUP_SCHED
|
|
bandwidth allocation to such task groups. It uses cgroups to group
|
|
tasks.
|
|
|
|
-if CGROUP_SCHED
|
|
+if CGROUP_SCHED && !SCHED_PDS
|
|
config FAIR_GROUP_SCHED
|
|
bool "Group scheduling for SCHED_OTHER"
|
|
depends on CGROUP_SCHED
|
|
@@ -1032,6 +1048,7 @@ config CGROUP_DEVICE
|
|
|
|
config CGROUP_CPUACCT
|
|
bool "Simple CPU accounting controller"
|
|
+ depends on !SCHED_PDS
|
|
help
|
|
Provides a simple controller for monitoring the
|
|
total CPU consumed by the tasks in a cgroup.
|
|
@@ -1150,6 +1167,7 @@ config CHECKPOINT_RESTORE
|
|
|
|
config SCHED_AUTOGROUP
|
|
bool "Automatic process group scheduling"
|
|
+ depends on !SCHED_PDS
|
|
select CGROUPS
|
|
select CGROUP_SCHED
|
|
select FAIR_GROUP_SCHED
|
|
diff --git a/init/init_task.c b/init/init_task.c
|
|
index 9e5cbe5eab7b..89787e2feb60 100644
|
|
--- a/init/init_task.c
|
|
+++ b/init/init_task.c
|
|
@@ -58,6 +58,126 @@ struct task_struct init_task
|
|
__init_task_data
|
|
#endif
|
|
= {
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+#ifdef CONFIG_THREAD_INFO_IN_TASK
|
|
+ .thread_info = INIT_THREAD_INFO(init_task),
|
|
+ .stack_refcount = ATOMIC_INIT(1),
|
|
+#endif
|
|
+ .state = 0,
|
|
+ .stack = init_stack,
|
|
+ .usage = ATOMIC_INIT(2),
|
|
+ .flags = PF_KTHREAD,
|
|
+ .prio = NORMAL_PRIO,
|
|
+ .static_prio = MAX_PRIO - 20,
|
|
+ .normal_prio = NORMAL_PRIO,
|
|
+ .deadline = 0, /* PDS only */
|
|
+ .policy = SCHED_NORMAL,
|
|
+ .cpus_ptr = &init_task.cpus_mask,
|
|
+ .cpus_mask = CPU_MASK_ALL,
|
|
+ .nr_cpus_allowed= NR_CPUS,
|
|
+ .mm = NULL,
|
|
+ .active_mm = &init_mm,
|
|
+ .restart_block = {
|
|
+ .fn = do_no_restart_syscall,
|
|
+ },
|
|
+ .sl_level = 0, /* PDS only */
|
|
+ .sl_node = SKIPLIST_NODE_INIT(init_task.sl_node), /* PDS only */
|
|
+ .time_slice = HZ, /* PDS only */
|
|
+ .tasks = LIST_HEAD_INIT(init_task.tasks),
|
|
+#ifdef CONFIG_SMP
|
|
+ .pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
|
|
+#endif
|
|
+#ifdef CONFIG_CGROUP_SCHED
|
|
+ .sched_task_group = &root_task_group,
|
|
+#endif
|
|
+ .ptraced = LIST_HEAD_INIT(init_task.ptraced),
|
|
+ .ptrace_entry = LIST_HEAD_INIT(init_task.ptrace_entry),
|
|
+ .real_parent = &init_task,
|
|
+ .parent = &init_task,
|
|
+ .children = LIST_HEAD_INIT(init_task.children),
|
|
+ .sibling = LIST_HEAD_INIT(init_task.sibling),
|
|
+ .group_leader = &init_task,
|
|
+ RCU_POINTER_INITIALIZER(real_cred, &init_cred),
|
|
+ RCU_POINTER_INITIALIZER(cred, &init_cred),
|
|
+ .comm = INIT_TASK_COMM,
|
|
+ .thread = INIT_THREAD,
|
|
+ .fs = &init_fs,
|
|
+ .files = &init_files,
|
|
+ .signal = &init_signals,
|
|
+ .sighand = &init_sighand,
|
|
+ .nsproxy = &init_nsproxy,
|
|
+ .pending = {
|
|
+ .list = LIST_HEAD_INIT(init_task.pending.list),
|
|
+ .signal = {{0}}
|
|
+ },
|
|
+ .blocked = {{0}},
|
|
+ .alloc_lock = __SPIN_LOCK_UNLOCKED(init_task.alloc_lock),
|
|
+ .journal_info = NULL,
|
|
+ INIT_CPU_TIMERS(init_task)
|
|
+ .pi_lock = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
|
|
+ .timer_slack_ns = 50000, /* 50 usec default slack */
|
|
+ .thread_pid = &init_struct_pid,
|
|
+ .thread_group = LIST_HEAD_INIT(init_task.thread_group),
|
|
+ .thread_node = LIST_HEAD_INIT(init_signals.thread_head),
|
|
+#ifdef CONFIG_AUDITSYSCALL
|
|
+ .loginuid = INVALID_UID,
|
|
+ .sessionid = AUDIT_SID_UNSET,
|
|
+#endif
|
|
+#ifdef CONFIG_PERF_EVENTS
|
|
+ .perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
|
|
+ .perf_event_list = LIST_HEAD_INIT(init_task.perf_event_list),
|
|
+#endif
|
|
+#ifdef CONFIG_PREEMPT_RCU
|
|
+ .rcu_read_lock_nesting = 0,
|
|
+ .rcu_read_unlock_special.s = 0,
|
|
+ .rcu_node_entry = LIST_HEAD_INIT(init_task.rcu_node_entry),
|
|
+ .rcu_blocked_node = NULL,
|
|
+#endif
|
|
+#ifdef CONFIG_TASKS_RCU
|
|
+ .rcu_tasks_holdout = false,
|
|
+ .rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list),
|
|
+ .rcu_tasks_idle_cpu = -1,
|
|
+#endif
|
|
+#ifdef CONFIG_CPUSETS
|
|
+ .mems_allowed_seq = SEQCNT_ZERO(init_task.mems_allowed_seq),
|
|
+#endif
|
|
+#ifdef CONFIG_RT_MUTEXES
|
|
+ .pi_waiters = RB_ROOT_CACHED,
|
|
+ .pi_top_task = NULL,
|
|
+#endif
|
|
+ INIT_PREV_CPUTIME(init_task)
|
|
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
|
|
+ .vtime.seqcount = SEQCNT_ZERO(init_task.vtime_seqcount),
|
|
+ .vtime.starttime = 0,
|
|
+ .vtime.state = VTIME_SYS,
|
|
+#endif
|
|
+#ifdef CONFIG_NUMA_BALANCING
|
|
+ .numa_preferred_nid = -1,
|
|
+ .numa_group = NULL,
|
|
+ .numa_faults = NULL,
|
|
+#endif
|
|
+#ifdef CONFIG_KASAN
|
|
+ .kasan_depth = 1,
|
|
+#endif
|
|
+#ifdef CONFIG_TRACE_IRQFLAGS
|
|
+ .softirqs_enabled = 1,
|
|
+#endif
|
|
+#ifdef CONFIG_LOCKDEP
|
|
+ .lockdep_recursion = 0,
|
|
+#endif
|
|
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
|
|
+ .ret_stack = NULL,
|
|
+#endif
|
|
+#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPT)
|
|
+ .trace_recursion = 0,
|
|
+#endif
|
|
+#ifdef CONFIG_LIVEPATCH
|
|
+ .patch_state = KLP_UNDEFINED,
|
|
+#endif
|
|
+#ifdef CONFIG_SECURITY
|
|
+ .security = NULL,
|
|
+#endif
|
|
+#else /* CONFIG_SCHED_PDS */
|
|
#ifdef CONFIG_THREAD_INFO_IN_TASK
|
|
.thread_info = INIT_THREAD_INFO(init_task),
|
|
.stack_refcount = REFCOUNT_INIT(1),
|
|
@@ -181,6 +301,7 @@ struct task_struct init_task
|
|
#ifdef CONFIG_SECURITY
|
|
.security = NULL,
|
|
#endif
|
|
+#endif /* CONFIG_SCHED_PDS */
|
|
};
|
|
EXPORT_SYMBOL(init_task);
|
|
|
|
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
|
|
index c87ee6412b36..4045c8532027 100644
|
|
--- a/kernel/cgroup/cpuset.c
|
|
+++ b/kernel/cgroup/cpuset.c
|
|
@@ -632,7 +632,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
|
|
return ret;
|
|
}
|
|
|
|
-#ifdef CONFIG_SMP
|
|
+#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_PDS)
|
|
/*
|
|
* Helper routine for generate_sched_domains().
|
|
* Do cpusets a, b have overlapping effective cpus_allowed masks?
|
|
@@ -1007,7 +1007,7 @@ static void rebuild_sched_domains_locked(void)
|
|
/* Have scheduler rebuild the domains */
|
|
partition_and_rebuild_sched_domains(ndoms, doms, attr);
|
|
}
|
|
-#else /* !CONFIG_SMP */
|
|
+#else /* !CONFIG_SMP || CONFIG_SCHED_PDS */
|
|
static void rebuild_sched_domains_locked(void)
|
|
{
|
|
}
|
|
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
|
|
index 27725754ac99..769d773c7182 100644
|
|
--- a/kernel/delayacct.c
|
|
+++ b/kernel/delayacct.c
|
|
@@ -106,7 +106,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
|
|
*/
|
|
t1 = tsk->sched_info.pcount;
|
|
t2 = tsk->sched_info.run_delay;
|
|
- t3 = tsk->se.sum_exec_runtime;
|
|
+ t3 = tsk_seruntime(tsk);
|
|
|
|
d->cpu_count += t1;
|
|
|
|
diff --git a/kernel/exit.c b/kernel/exit.c
|
|
index a46a50d67002..58043176b285 100644
|
|
--- a/kernel/exit.c
|
|
+++ b/kernel/exit.c
|
|
@@ -131,7 +131,7 @@ static void __exit_signal(struct task_struct *tsk)
|
|
sig->curr_target = next_thread(tsk);
|
|
}
|
|
|
|
- add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
|
|
+ add_device_randomness((const void*) &tsk_seruntime(tsk),
|
|
sizeof(unsigned long long));
|
|
|
|
/*
|
|
@@ -152,7 +152,7 @@ static void __exit_signal(struct task_struct *tsk)
|
|
sig->inblock += task_io_get_inblock(tsk);
|
|
sig->oublock += task_io_get_oublock(tsk);
|
|
task_io_accounting_add(&sig->ioac, &tsk->ioac);
|
|
- sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
|
|
+ sig->sum_sched_runtime += tsk_seruntime(tsk);
|
|
sig->nr_threads--;
|
|
__unhash_process(tsk, group_dead);
|
|
write_sequnlock(&sig->stats_lock);
|
|
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
|
|
index cdf318d86dd6..baa525865d5c 100644
|
|
--- a/kernel/livepatch/transition.c
|
|
+++ b/kernel/livepatch/transition.c
|
|
@@ -306,7 +306,11 @@ static bool klp_try_switch_task(struct task_struct *task)
|
|
*/
|
|
rq = task_rq_lock(task, &flags);
|
|
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+ if (task_running(task) && task != current) {
|
|
+#else
|
|
if (task_running(rq, task) && task != current) {
|
|
+#endif
|
|
snprintf(err_buf, STACK_ERR_BUF_SIZE,
|
|
"%s: %s:%d is running\n", __func__, task->comm,
|
|
task->pid);
|
|
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
|
|
index 2874bf556162..fad8a279fdfa 100644
|
|
--- a/kernel/locking/rtmutex.c
|
|
+++ b/kernel/locking/rtmutex.c
|
|
@@ -229,7 +229,7 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
|
|
* Only use with rt_mutex_waiter_{less,equal}()
|
|
*/
|
|
#define task_to_waiter(p) \
|
|
- &(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
|
|
+ &(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = __tsk_deadline(p) }
|
|
|
|
static inline int
|
|
rt_mutex_waiter_less(struct rt_mutex_waiter *left,
|
|
@@ -680,7 +680,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
|
|
* the values of the node being removed.
|
|
*/
|
|
waiter->prio = task->prio;
|
|
- waiter->deadline = task->dl.deadline;
|
|
+ waiter->deadline = __tsk_deadline(task);
|
|
|
|
rt_mutex_enqueue(lock, waiter);
|
|
|
|
@@ -953,7 +953,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
|
|
waiter->task = task;
|
|
waiter->lock = lock;
|
|
waiter->prio = task->prio;
|
|
- waiter->deadline = task->dl.deadline;
|
|
+ waiter->deadline = __tsk_deadline(task);
|
|
|
|
/* Get the top priority waiter on the lock */
|
|
if (rt_mutex_has_waiters(lock))
|
|
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
|
|
index 21fb5a5662b5..8ebe4e33fb5f 100644
|
|
--- a/kernel/sched/Makefile
|
|
+++ b/kernel/sched/Makefile
|
|
@@ -16,15 +16,21 @@ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
|
|
CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
|
|
endif
|
|
|
|
-obj-y += core.o loadavg.o clock.o cputime.o
|
|
-obj-y += idle.o fair.o rt.o deadline.o
|
|
-obj-y += wait.o wait_bit.o swait.o completion.o
|
|
-
|
|
-obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o pelt.o
|
|
+ifdef CONFIG_SCHED_PDS
|
|
+obj-y += pds.o
|
|
+else
|
|
+obj-y += core.o
|
|
+obj-y += fair.o rt.o deadline.o
|
|
+obj-$(CONFIG_SMP) += cpudeadline.o topology.o stop_task.o
|
|
obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o
|
|
-obj-$(CONFIG_SCHEDSTATS) += stats.o
|
|
obj-$(CONFIG_SCHED_DEBUG) += debug.o
|
|
obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
|
|
+endif
|
|
+obj-y += loadavg.o clock.o cputime.o
|
|
+obj-y += idle.o
|
|
+obj-y += wait.o wait_bit.o swait.o completion.o
|
|
+obj-$(CONFIG_SMP) += cpupri.o pelt.o
|
|
+obj-$(CONFIG_SCHEDSTATS) += stats.o
|
|
obj-$(CONFIG_CPU_FREQ) += cpufreq.o
|
|
obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
|
|
obj-$(CONFIG_MEMBARRIER) += membarrier.o
|
|
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
|
|
index 86800b4d5453..07f278dc3137 100644
|
|
--- a/kernel/sched/cpufreq_schedutil.c
|
|
+++ b/kernel/sched/cpufreq_schedutil.c
|
|
@@ -185,6 +185,7 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
|
|
return cpufreq_driver_resolve_freq(policy, freq);
|
|
}
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
/*
|
|
* This function computes an effective utilization for the given CPU, to be
|
|
* used for frequency selection given the linear relation: f = u * f_max.
|
|
@@ -302,6 +303,13 @@ static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
|
|
|
|
return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL);
|
|
}
|
|
+#else /* CONFIG_SCHED_PDS */
|
|
+static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
|
|
+{
|
|
+ sg_cpu->max = arch_scale_cpu_capacity(sg_cpu->cpu);
|
|
+ return sg_cpu->max;
|
|
+}
|
|
+#endif
|
|
|
|
/**
|
|
* sugov_iowait_reset() - Reset the IO boost status of a CPU.
|
|
@@ -445,7 +453,9 @@ static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
|
|
*/
|
|
static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
|
|
{
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
|
|
+#endif
|
|
sg_policy->limits_changed = true;
|
|
}
|
|
|
|
@@ -688,6 +698,7 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
|
|
}
|
|
|
|
ret = sched_setattr_nocheck(thread, &attr);
|
|
+
|
|
if (ret) {
|
|
kthread_stop(thread);
|
|
pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
|
|
@@ -918,6 +929,7 @@ static int __init sugov_register(void)
|
|
fs_initcall(sugov_register);
|
|
|
|
#ifdef CONFIG_ENERGY_MODEL
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
extern bool sched_energy_update;
|
|
extern struct mutex sched_energy_mutex;
|
|
|
|
@@ -948,4 +960,10 @@ void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
|
|
}
|
|
|
|
}
|
|
+#else /* CONFIG_SCHED_PDS */
|
|
+void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
|
|
+ struct cpufreq_governor *old_gov)
|
|
+{
|
|
+}
|
|
+#endif
|
|
#endif
|
|
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
|
|
index 46ed4e1383e2..0a9548ee995c 100644
|
|
--- a/kernel/sched/cputime.c
|
|
+++ b/kernel/sched/cputime.c
|
|
@@ -122,7 +122,12 @@ void account_user_time(struct task_struct *p, u64 cputime)
|
|
p->utime += cputime;
|
|
account_group_user_time(p, cputime);
|
|
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+ index = (task_nice(p) > 0 || task_running_idle(p)) ? CPUTIME_NICE :
|
|
+ CPUTIME_USER;
|
|
+#else
|
|
index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
|
|
+#endif
|
|
|
|
/* Add user time to cpustat. */
|
|
task_group_account_field(p, index, cputime);
|
|
@@ -146,7 +151,11 @@ void account_guest_time(struct task_struct *p, u64 cputime)
|
|
p->gtime += cputime;
|
|
|
|
/* Add guest time to cpustat. */
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+ if (task_nice(p) > 0 || task_running_idle(p)) {
|
|
+#else
|
|
if (task_nice(p) > 0) {
|
|
+#endif
|
|
cpustat[CPUTIME_NICE] += cputime;
|
|
cpustat[CPUTIME_GUEST_NICE] += cputime;
|
|
} else {
|
|
@@ -269,7 +278,7 @@ static inline u64 account_other_time(u64 max)
|
|
#ifdef CONFIG_64BIT
|
|
static inline u64 read_sum_exec_runtime(struct task_struct *t)
|
|
{
|
|
- return t->se.sum_exec_runtime;
|
|
+ return tsk_seruntime(t);
|
|
}
|
|
#else
|
|
static u64 read_sum_exec_runtime(struct task_struct *t)
|
|
@@ -279,7 +288,7 @@ static u64 read_sum_exec_runtime(struct task_struct *t)
|
|
struct rq *rq;
|
|
|
|
rq = task_rq_lock(t, &rf);
|
|
- ns = t->se.sum_exec_runtime;
|
|
+ ns = tsk_seruntime(t);
|
|
task_rq_unlock(rq, t, &rf);
|
|
|
|
return ns;
|
|
@@ -663,7 +672,7 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
|
|
void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
|
|
{
|
|
struct task_cputime cputime = {
|
|
- .sum_exec_runtime = p->se.sum_exec_runtime,
|
|
+ .sum_exec_runtime = tsk_seruntime(p),
|
|
};
|
|
|
|
task_cputime(p, &cputime.utime, &cputime.stime);
|
|
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
|
|
index f65ef1e2f204..454fa7e460e3 100644
|
|
--- a/kernel/sched/idle.c
|
|
+++ b/kernel/sched/idle.c
|
|
@@ -355,6 +355,7 @@ void cpu_startup_entry(enum cpuhp_state state)
|
|
do_idle();
|
|
}
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
/*
|
|
* idle-task scheduling class.
|
|
*/
|
|
@@ -479,3 +480,4 @@ const struct sched_class idle_sched_class = {
|
|
.switched_to = switched_to_idle,
|
|
.update_curr = update_curr_idle,
|
|
};
|
|
+#endif
|
|
diff --git a/kernel/sched/pds.c b/kernel/sched/pds.c
|
|
new file mode 100644
|
|
index 000000000000..aefbd9cebcfb
|
|
--- /dev/null
|
|
+++ b/kernel/sched/pds.c
|
|
@@ -0,0 +1,6566 @@
|
|
+/*
|
|
+ * kernel/sched/pds.c, was kernel/sched.c
|
|
+ *
|
|
+ * PDS-mq Core kernel scheduler code and related syscalls
|
|
+ *
|
|
+ * Copyright (C) 1991-2002 Linus Torvalds
|
|
+ *
|
|
+ * 2009-08-13 Brainfuck deadline scheduling policy by Con Kolivas deletes
|
|
+ * a whole lot of those previous things.
|
|
+ * 2017-09-06 Priority and Deadline based Skip list multiple queue kernel
|
|
+ * scheduler by Alfred Chen.
|
|
+ */
|
|
+#include "pds_sched.h"
|
|
+
|
|
+#include <linux/sched/rt.h>
|
|
+
|
|
+#include <linux/context_tracking.h>
|
|
+#include <linux/compat.h>
|
|
+#include <linux/blkdev.h>
|
|
+#include <linux/delayacct.h>
|
|
+#include <linux/freezer.h>
|
|
+#include <linux/init_task.h>
|
|
+#include <linux/kprobes.h>
|
|
+#include <linux/mmu_context.h>
|
|
+#include <linux/nmi.h>
|
|
+#include <linux/profile.h>
|
|
+#include <linux/rcupdate_wait.h>
|
|
+#include <linux/security.h>
|
|
+#include <linux/syscalls.h>
|
|
+#include <linux/wait_bit.h>
|
|
+
|
|
+#include <linux/kcov.h>
|
|
+
|
|
+#include <asm/switch_to.h>
|
|
+
|
|
+#include "../workqueue_internal.h"
|
|
+#include "../smpboot.h"
|
|
+
|
|
+#include "pelt.h"
|
|
+
|
|
+#define CREATE_TRACE_POINTS
|
|
+#include <trace/events/sched.h>
|
|
+
|
|
+
|
|
+#define rt_prio(prio) ((prio) < MAX_RT_PRIO)
|
|
+#define rt_task(p) rt_prio((p)->prio)
|
|
+#define rt_policy(policy) ((policy) == SCHED_FIFO || \
|
|
+ (policy) == SCHED_RR || \
|
|
+ (policy) == SCHED_ISO)
|
|
+#define task_has_rt_policy(p) (rt_policy((p)->policy))
|
|
+
|
|
+#define idle_policy(policy) ((policy) == SCHED_IDLE)
|
|
+#define idleprio_task(p) unlikely(idle_policy((p)->policy))
|
|
+
|
|
+#define STOP_PRIO (MAX_RT_PRIO - 1)
|
|
+
|
|
+/*
|
|
+ * Some helpers for converting to/from various scales. Use shifts to get
|
|
+ * approximate multiples of ten for less overhead.
|
|
+ */
|
|
+#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ))
|
|
+#define JIFFY_NS (1000000000 / HZ)
|
|
+#define HALF_JIFFY_NS (1000000000 / HZ / 2)
|
|
+#define HALF_JIFFY_US (1000000 / HZ / 2)
|
|
+#define MS_TO_NS(TIME) ((TIME) << 20)
|
|
+#define MS_TO_US(TIME) ((TIME) << 10)
|
|
+#define NS_TO_MS(TIME) ((TIME) >> 20)
|
|
+#define NS_TO_US(TIME) ((TIME) >> 10)
|
|
+#define US_TO_NS(TIME) ((TIME) << 10)
|
|
+
|
|
+#define RESCHED_US (100) /* Reschedule if less than this many μs left */
|
|
+
|
|
+enum {
|
|
+ BASE_CPU_AFFINITY_CHK_LEVEL = 1,
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ SMT_CPU_AFFINITY_CHK_LEVEL_SPACE_HOLDER,
|
|
+#endif
|
|
+#ifdef CONFIG_SCHED_MC
|
|
+ MC_CPU_AFFINITY_CHK_LEVEL_SPACE_HOLDER,
|
|
+#endif
|
|
+ NR_CPU_AFFINITY_CHK_LEVEL
|
|
+};
|
|
+
|
|
+static inline void print_scheduler_version(void)
|
|
+{
|
|
+ printk(KERN_INFO "pds: PDS-mq CPU Scheduler 0.99o by Alfred Chen and kept alive artificially by Tk-Glitch.\n");
|
|
+}
|
|
+
|
|
+/*
|
|
+ * This is the time all tasks within the same priority round robin.
|
|
+ * Value is in ms and set to a minimum of 6ms. Scales with number of cpus.
|
|
+ * Tunable via /proc interface.
|
|
+ */
|
|
+#define SCHED_DEFAULT_RR (4)
|
|
+int rr_interval __read_mostly = SCHED_DEFAULT_RR;
|
|
+
|
|
+static int __init rr_interval_set(char *str)
|
|
+{
|
|
+ u32 rr;
|
|
+
|
|
+ pr_info("rr_interval: ");
|
|
+ if (kstrtouint(str, 0, &rr)) {
|
|
+ pr_cont("using default of %u, unable to parse %s\n",
|
|
+ rr_interval, str);
|
|
+ return 1;
|
|
+ }
|
|
+
|
|
+ rr_interval = rr;
|
|
+ pr_cont("%d\n", rr_interval);
|
|
+
|
|
+ return 1;
|
|
+}
|
|
+__setup("rr_interval=", rr_interval_set);
|
|
+
|
|
+
|
|
+static const u64 sched_prio2deadline[NICE_WIDTH] = {
|
|
+/* -20 */ 6291456, 6920601, 7612661, 8373927, 9211319,
|
|
+/* -15 */ 10132450, 11145695, 12260264, 13486290, 14834919,
|
|
+/* -10 */ 16318410, 17950251, 19745276, 21719803, 23891783,
|
|
+/* -5 */ 26280961, 28909057, 31799962, 34979958, 38477953,
|
|
+/* 0 */ 42325748, 46558322, 51214154, 56335569, 61969125,
|
|
+/* 5 */ 68166037, 74982640, 82480904, 90728994, 99801893,
|
|
+/* 10 */ 109782082, 120760290, 132836319, 146119950, 160731945,
|
|
+/* 15 */ 176805139, 194485652, 213934217, 235327638, 258860401
|
|
+};
|
|
+
|
|
+/**
|
|
+ * sched_yield_type - Choose what sort of yield sched_yield will perform.
|
|
+ * 0: No yield.
|
|
+ * 1: Yield only to better priority/deadline tasks. (default)
|
|
+ * 2: Expire timeslice and recalculate deadline.
|
|
+ */
|
|
+int sched_yield_type __read_mostly = 1;
|
|
+
|
|
+/*
|
|
+ * The quota handed out to tasks of all priority levels when refilling their
|
|
+ * time_slice.
|
|
+ */
|
|
+static inline int timeslice(void)
|
|
+{
|
|
+ return MS_TO_US(rr_interval);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+enum {
|
|
+SCHED_RQ_EMPTY = 0,
|
|
+SCHED_RQ_IDLE,
|
|
+SCHED_RQ_NORMAL_0,
|
|
+SCHED_RQ_NORMAL_1,
|
|
+SCHED_RQ_NORMAL_2,
|
|
+SCHED_RQ_NORMAL_3,
|
|
+SCHED_RQ_NORMAL_4,
|
|
+SCHED_RQ_NORMAL_5,
|
|
+SCHED_RQ_NORMAL_6,
|
|
+SCHED_RQ_NORMAL_7,
|
|
+SCHED_RQ_ISO,
|
|
+SCHED_RQ_RT,
|
|
+NR_SCHED_RQ_QUEUED_LEVEL
|
|
+};
|
|
+
|
|
+static cpumask_t sched_rq_queued_masks[NR_SCHED_RQ_QUEUED_LEVEL]
|
|
+____cacheline_aligned_in_smp;
|
|
+
|
|
+static DECLARE_BITMAP(sched_rq_queued_masks_bitmap, NR_SCHED_RQ_QUEUED_LEVEL)
|
|
+____cacheline_aligned_in_smp;
|
|
+
|
|
+static cpumask_t sched_rq_pending_masks[NR_SCHED_RQ_QUEUED_LEVEL]
|
|
+____cacheline_aligned_in_smp;
|
|
+
|
|
+static DECLARE_BITMAP(sched_rq_pending_masks_bitmap, NR_SCHED_RQ_QUEUED_LEVEL)
|
|
+____cacheline_aligned_in_smp;
|
|
+
|
|
+DEFINE_PER_CPU(cpumask_t [NR_CPU_AFFINITY_CHK_LEVEL], sched_cpu_affinity_chk_masks);
|
|
+DEFINE_PER_CPU(cpumask_t *, sched_cpu_llc_start_mask);
|
|
+DEFINE_PER_CPU(cpumask_t *, sched_cpu_affinity_chk_end_masks);
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+DEFINE_PER_CPU(int, sched_sibling_cpu);
|
|
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
|
|
+EXPORT_SYMBOL_GPL(sched_smt_present);
|
|
+
|
|
+static cpumask_t sched_cpu_sg_idle_mask ____cacheline_aligned_in_smp;
|
|
+
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+/*
|
|
+ * Preemptible sibling group mask
|
|
+ * Which all sibling cpus are running at PRIO_LIMIT or IDLE_PRIO
|
|
+ */
|
|
+static cpumask_t sched_cpu_psg_mask ____cacheline_aligned_in_smp;
|
|
+/*
|
|
+ * SMT supressed mask
|
|
+ * When a cpu is running task with NORMAL/ISO/RT policy, its sibling cpu
|
|
+ * will be supressed to run IDLE priority task.
|
|
+ */
|
|
+static cpumask_t sched_smt_supressed_mask ____cacheline_aligned_in_smp;
|
|
+#endif /* CONFIG_SMT_NICE */
|
|
+#endif
|
|
+
|
|
+static int sched_rq_prio[NR_CPUS] ____cacheline_aligned;
|
|
+
|
|
+/*
|
|
+ * Keep a unique ID per domain (we use the first CPUs number in the cpumask of
|
|
+ * the domain), this allows us to quickly tell if two cpus are in the same cache
|
|
+ * domain, see cpus_share_cache().
|
|
+ */
|
|
+DEFINE_PER_CPU(int, sd_llc_id);
|
|
+
|
|
+int __weak arch_sd_sibling_asym_packing(void)
|
|
+{
|
|
+ return 0*SD_ASYM_PACKING;
|
|
+}
|
|
+#else
|
|
+struct rq *uprq;
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+static DEFINE_MUTEX(sched_hotcpu_mutex);
|
|
+
|
|
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
|
|
+
|
|
+#ifndef prepare_arch_switch
|
|
+# define prepare_arch_switch(next) do { } while (0)
|
|
+#endif
|
|
+#ifndef finish_arch_post_lock_switch
|
|
+# define finish_arch_post_lock_switch() do { } while (0)
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * Context: p->pi_lock
|
|
+ */
|
|
+static inline struct rq
|
|
+*__task_access_lock(struct task_struct *p, raw_spinlock_t **plock)
|
|
+{
|
|
+ struct rq *rq;
|
|
+ for (;;) {
|
|
+ rq = task_rq(p);
|
|
+ if (p->on_cpu || task_on_rq_queued(p)) {
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ if (likely((p->on_cpu || task_on_rq_queued(p))
|
|
+ && rq == task_rq(p))) {
|
|
+ *plock = &rq->lock;
|
|
+ return rq;
|
|
+ }
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ } else if (task_on_rq_migrating(p)) {
|
|
+ do {
|
|
+ cpu_relax();
|
|
+ } while (unlikely(task_on_rq_migrating(p)));
|
|
+ } else {
|
|
+ *plock = NULL;
|
|
+ return rq;
|
|
+ }
|
|
+ }
|
|
+}
|
|
+
|
|
+static inline void
|
|
+__task_access_unlock(struct task_struct *p, raw_spinlock_t *lock)
|
|
+{
|
|
+ if (NULL != lock)
|
|
+ raw_spin_unlock(lock);
|
|
+}
|
|
+
|
|
+static inline struct rq
|
|
+*task_access_lock_irqsave(struct task_struct *p, raw_spinlock_t **plock,
|
|
+ unsigned long *flags)
|
|
+{
|
|
+ struct rq *rq;
|
|
+ for (;;) {
|
|
+ rq = task_rq(p);
|
|
+ if (p->on_cpu || task_on_rq_queued(p)) {
|
|
+ raw_spin_lock_irqsave(&rq->lock, *flags);
|
|
+ if (likely((p->on_cpu || task_on_rq_queued(p))
|
|
+ && rq == task_rq(p))) {
|
|
+ *plock = &rq->lock;
|
|
+ return rq;
|
|
+ }
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, *flags);
|
|
+ } else if (task_on_rq_migrating(p)) {
|
|
+ do {
|
|
+ cpu_relax();
|
|
+ } while (unlikely(task_on_rq_migrating(p)));
|
|
+ } else {
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, *flags);
|
|
+ if (likely(!p->on_cpu && !p->on_rq &&
|
|
+ rq == task_rq(p))) {
|
|
+ *plock = &p->pi_lock;
|
|
+ return rq;
|
|
+ }
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
|
|
+ }
|
|
+ }
|
|
+}
|
|
+
|
|
+static inline void
|
|
+task_access_unlock_irqrestore(struct task_struct *p, raw_spinlock_t *lock,
|
|
+ unsigned long *flags)
|
|
+{
|
|
+ raw_spin_unlock_irqrestore(lock, *flags);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * __task_rq_lock - lock the rq @p resides on.
|
|
+ */
|
|
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
|
|
+ __acquires(rq->lock)
|
|
+{
|
|
+ struct rq *rq;
|
|
+
|
|
+ lockdep_assert_held(&p->pi_lock);
|
|
+
|
|
+ for (;;) {
|
|
+ rq = task_rq(p);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
|
|
+ return rq;
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+
|
|
+ while (unlikely(task_on_rq_migrating(p)))
|
|
+ cpu_relax();
|
|
+ }
|
|
+}
|
|
+
|
|
+/*
|
|
+ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
|
|
+ */
|
|
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
|
|
+ __acquires(p->pi_lock)
|
|
+ __acquires(rq->lock)
|
|
+{
|
|
+ struct rq *rq;
|
|
+
|
|
+ for (;;) {
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
|
|
+ rq = task_rq(p);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ /*
|
|
+ * move_queued_task() task_rq_lock()
|
|
+ *
|
|
+ * ACQUIRE (rq->lock)
|
|
+ * [S] ->on_rq = MIGRATING [L] rq = task_rq()
|
|
+ * WMB (__set_task_cpu()) ACQUIRE (rq->lock);
|
|
+ * [S] ->cpu = new_cpu [L] task_rq()
|
|
+ * [L] ->on_rq
|
|
+ * RELEASE (rq->lock)
|
|
+ *
|
|
+ * If we observe the old CPU in task_rq_lock(), the acquire of
|
|
+ * the old rq->lock will fully serialize against the stores.
|
|
+ *
|
|
+ * If we observe the new CPU in task_rq_lock(), the address
|
|
+ * dependency headed by '[L] rq = task_rq()' and the acquire
|
|
+ * will pair with the WMB to ensure we then also see migrating.
|
|
+ */
|
|
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
|
|
+ return rq;
|
|
+ }
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
|
|
+
|
|
+ while (unlikely(task_on_rq_migrating(p)))
|
|
+ cpu_relax();
|
|
+ }
|
|
+}
|
|
+
|
|
+/*
|
|
+ * RQ-clock updating methods:
|
|
+ */
|
|
+
|
|
+static void update_rq_clock_task(struct rq *rq, s64 delta)
|
|
+{
|
|
+/*
|
|
+ * In theory, the compile should just see 0 here, and optimize out the call
|
|
+ * to sched_rt_avg_update. But I don't trust it...
|
|
+ */
|
|
+ s64 __maybe_unused steal = 0, irq_delta = 0;
|
|
+
|
|
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
+ irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
|
|
+
|
|
+ /*
|
|
+ * Since irq_time is only updated on {soft,}irq_exit, we might run into
|
|
+ * this case when a previous update_rq_clock() happened inside a
|
|
+ * {soft,}irq region.
|
|
+ *
|
|
+ * When this happens, we stop ->clock_task and only update the
|
|
+ * prev_irq_time stamp to account for the part that fit, so that a next
|
|
+ * update will consume the rest. This ensures ->clock_task is
|
|
+ * monotonic.
|
|
+ *
|
|
+ * It does however cause some slight miss-attribution of {soft,}irq
|
|
+ * time, a more accurate solution would be to update the irq_time using
|
|
+ * the current rq->clock timestamp, except that would require using
|
|
+ * atomic ops.
|
|
+ */
|
|
+ if (irq_delta > delta)
|
|
+ irq_delta = delta;
|
|
+
|
|
+ rq->prev_irq_time += irq_delta;
|
|
+ delta -= irq_delta;
|
|
+#endif
|
|
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
|
|
+ if (static_key_false((¶virt_steal_rq_enabled))) {
|
|
+ steal = paravirt_steal_clock(cpu_of(rq));
|
|
+ steal -= rq->prev_steal_time_rq;
|
|
+
|
|
+ if (unlikely(steal > delta))
|
|
+ steal = delta;
|
|
+
|
|
+ rq->prev_steal_time_rq += steal;
|
|
+
|
|
+ delta -= steal;
|
|
+ }
|
|
+#endif
|
|
+
|
|
+ rq->clock_task += delta;
|
|
+
|
|
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
|
|
+ if ((irq_delta + steal))
|
|
+ update_irq_load_avg(rq, irq_delta + steal);
|
|
+#endif
|
|
+}
|
|
+
|
|
+static inline void update_rq_clock(struct rq *rq)
|
|
+{
|
|
+ s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
|
|
+
|
|
+ if (unlikely(delta <= 0))
|
|
+ return;
|
|
+ rq->clock += delta;
|
|
+ update_rq_clock_task(rq, delta);
|
|
+}
|
|
+
|
|
+static inline void update_task_priodl(struct task_struct *p)
|
|
+{
|
|
+ p->priodl = (((u64) (p->prio))<<56) | ((p->deadline)>>8);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Deadline is "now" in niffies + (offset by priority). Setting the deadline
|
|
+ * is the key to everything. It distributes CPU fairly amongst tasks of the
|
|
+ * same nice value, it proportions CPU according to nice level, it means the
|
|
+ * task that last woke up the longest ago has the earliest deadline, thus
|
|
+ * ensuring that interactive tasks get low latency on wake up. The CPU
|
|
+ * proportion works out to the square of the virtual deadline difference, so
|
|
+ * this equation will give nice 19 3% CPU compared to nice 0.
|
|
+ */
|
|
+static inline u64 task_deadline_diff(const struct task_struct *p)
|
|
+{
|
|
+ return sched_prio2deadline[TASK_USER_PRIO(p)];
|
|
+}
|
|
+
|
|
+static inline u64 static_deadline_diff(int static_prio)
|
|
+{
|
|
+ return sched_prio2deadline[USER_PRIO(static_prio)];
|
|
+}
|
|
+
|
|
+/*
|
|
+ * The time_slice is only refilled when it is empty and that is when we set a
|
|
+ * new deadline for non-rt tasks.
|
|
+ */
|
|
+static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ p->time_slice = timeslice();
|
|
+ if (p->prio >= NORMAL_PRIO)
|
|
+ p->deadline = rq->clock + task_deadline_diff(p);
|
|
+
|
|
+ update_task_priodl(p);
|
|
+}
|
|
+
|
|
+static inline struct task_struct *rq_first_queued_task(struct rq *rq)
|
|
+{
|
|
+ struct skiplist_node *node = rq->sl_header.next[0];
|
|
+
|
|
+ if (node == &rq->sl_header)
|
|
+ return rq->idle;
|
|
+
|
|
+ return skiplist_entry(node, struct task_struct, sl_node);
|
|
+}
|
|
+
|
|
+static inline struct task_struct *rq_second_queued_task(struct rq *rq)
|
|
+{
|
|
+ struct skiplist_node *node = rq->sl_header.next[0]->next[0];
|
|
+
|
|
+ if (node == &rq->sl_header)
|
|
+ return rq->idle;
|
|
+
|
|
+ return skiplist_entry(node, struct task_struct, sl_node);
|
|
+}
|
|
+
|
|
+static inline int is_second_in_rq(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ return (p->sl_node.prev[0]->prev[0] == &rq->sl_header);
|
|
+}
|
|
+
|
|
+static const int task_dl_hash_tbl[] = {
|
|
+/* 0 4 8 12 */
|
|
+ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1,
|
|
+/* 16 20 24 28 */
|
|
+ 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 6, 7
|
|
+};
|
|
+
|
|
+static inline int
|
|
+task_deadline_level(const struct task_struct *p, const struct rq *rq)
|
|
+{
|
|
+ u64 delta = (rq->clock + sched_prio2deadline[39] - p->deadline) >> 23;
|
|
+
|
|
+ delta = min((size_t)delta, ARRAY_SIZE(task_dl_hash_tbl) - 1);
|
|
+ return task_dl_hash_tbl[delta];
|
|
+}
|
|
+
|
|
+/*
|
|
+ * cmpxchg based fetch_or, macro so it works for different integer types
|
|
+ */
|
|
+#define fetch_or(ptr, mask) \
|
|
+ ({ \
|
|
+ typeof(ptr) _ptr = (ptr); \
|
|
+ typeof(mask) _mask = (mask); \
|
|
+ typeof(*_ptr) _old, _val = *_ptr; \
|
|
+ \
|
|
+ for (;;) { \
|
|
+ _old = cmpxchg(_ptr, _val, _val | _mask); \
|
|
+ if (_old == _val) \
|
|
+ break; \
|
|
+ _val = _old; \
|
|
+ } \
|
|
+ _old; \
|
|
+})
|
|
+
|
|
+#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
|
|
+/*
|
|
+ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
|
|
+ * this avoids any races wrt polling state changes and thereby avoids
|
|
+ * spurious IPIs.
|
|
+ */
|
|
+static bool set_nr_and_not_polling(struct task_struct *p)
|
|
+{
|
|
+ struct thread_info *ti = task_thread_info(p);
|
|
+ return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
|
|
+ *
|
|
+ * If this returns true, then the idle task promises to call
|
|
+ * sched_ttwu_pending() and reschedule soon.
|
|
+ */
|
|
+static bool set_nr_if_polling(struct task_struct *p)
|
|
+{
|
|
+ struct thread_info *ti = task_thread_info(p);
|
|
+ typeof(ti->flags) old, val = READ_ONCE(ti->flags);
|
|
+
|
|
+ for (;;) {
|
|
+ if (!(val & _TIF_POLLING_NRFLAG))
|
|
+ return false;
|
|
+ if (val & _TIF_NEED_RESCHED)
|
|
+ return true;
|
|
+ old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
|
|
+ if (old == val)
|
|
+ break;
|
|
+ val = old;
|
|
+ }
|
|
+ return true;
|
|
+}
|
|
+
|
|
+#else
|
|
+static bool set_nr_and_not_polling(struct task_struct *p)
|
|
+{
|
|
+ set_tsk_need_resched(p);
|
|
+ return true;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+static bool set_nr_if_polling(struct task_struct *p)
|
|
+{
|
|
+ return false;
|
|
+}
|
|
+#endif
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+static void resched_cpu_if_curr_is(int cpu, int priority)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+
|
|
+ rcu_read_lock();
|
|
+
|
|
+ if (rcu_dereference(rq->curr)->prio != priority)
|
|
+ goto out;
|
|
+
|
|
+ if (set_nr_if_polling(rq->idle)) {
|
|
+ trace_sched_wake_idle_without_ipi(cpu);
|
|
+ } else {
|
|
+ if (!do_raw_spin_trylock(&rq->lock))
|
|
+ goto out;
|
|
+ spin_acquire(&rq->lock.dep_map, SINGLE_DEPTH_NESTING, 1, _RET_IP_);
|
|
+
|
|
+ if (priority == rq->curr->prio)
|
|
+ smp_send_reschedule(cpu);
|
|
+ /* Else CPU is not idle, do nothing here */
|
|
+
|
|
+ spin_release(&rq->lock.dep_map, 1, _RET_IP_);
|
|
+ do_raw_spin_unlock(&rq->lock);
|
|
+ }
|
|
+
|
|
+out:
|
|
+ rcu_read_unlock();
|
|
+}
|
|
+#endif /* CONFIG_SMT_NICE */
|
|
+
|
|
+static inline bool
|
|
+__update_cpumasks_bitmap(int cpu, unsigned long *plevel, unsigned long level,
|
|
+ cpumask_t cpumasks[], unsigned long bitmap[])
|
|
+{
|
|
+ if (*plevel == level)
|
|
+ return false;
|
|
+
|
|
+ cpumask_clear_cpu(cpu, cpumasks + *plevel);
|
|
+ if (cpumask_empty(cpumasks + *plevel))
|
|
+ clear_bit(*plevel, bitmap);
|
|
+ cpumask_set_cpu(cpu, cpumasks + level);
|
|
+ set_bit(level, bitmap);
|
|
+
|
|
+ *plevel = level;
|
|
+
|
|
+ return true;
|
|
+}
|
|
+
|
|
+static inline int
|
|
+task_running_policy_level(const struct task_struct *p, const struct rq *rq)
|
|
+{
|
|
+ int prio = p->prio;
|
|
+
|
|
+ if (NORMAL_PRIO == prio)
|
|
+ return SCHED_RQ_NORMAL_0 + task_deadline_level(p, rq);
|
|
+
|
|
+ if (ISO_PRIO == prio)
|
|
+ return SCHED_RQ_ISO;
|
|
+ if (prio < MAX_RT_PRIO)
|
|
+ return SCHED_RQ_RT;
|
|
+ return PRIO_LIMIT - prio;
|
|
+}
|
|
+
|
|
+static inline void update_sched_rq_queued_masks_normal(struct rq *rq)
|
|
+{
|
|
+ struct task_struct *p = rq_first_queued_task(rq);
|
|
+
|
|
+ if (p->prio != NORMAL_PRIO)
|
|
+ return;
|
|
+
|
|
+ __update_cpumasks_bitmap(cpu_of(rq), &rq->queued_level,
|
|
+ task_running_policy_level(p, rq),
|
|
+ &sched_rq_queued_masks[0],
|
|
+ &sched_rq_queued_masks_bitmap[0]);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+static inline void update_sched_cpu_psg_mask(const int cpu)
|
|
+{
|
|
+ cpumask_t tmp;
|
|
+
|
|
+ cpumask_or(&tmp, &sched_rq_queued_masks[SCHED_RQ_EMPTY],
|
|
+ &sched_rq_queued_masks[SCHED_RQ_IDLE]);
|
|
+ cpumask_and(&tmp, &tmp, cpu_smt_mask(cpu));
|
|
+ if (cpumask_equal(&tmp, cpu_smt_mask(cpu)))
|
|
+ cpumask_or(&sched_cpu_psg_mask, &sched_cpu_psg_mask,
|
|
+ cpu_smt_mask(cpu));
|
|
+ else
|
|
+ cpumask_andnot(&sched_cpu_psg_mask, &sched_cpu_psg_mask,
|
|
+ cpu_smt_mask(cpu));
|
|
+}
|
|
+#endif
|
|
+
|
|
+static inline void update_sched_rq_queued_masks(struct rq *rq)
|
|
+{
|
|
+ int cpu = cpu_of(rq);
|
|
+ struct task_struct *p = rq_first_queued_task(rq);
|
|
+ unsigned long level;
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ unsigned long last_level = rq->queued_level;
|
|
+#endif
|
|
+
|
|
+ level = task_running_policy_level(p, rq);
|
|
+ sched_rq_prio[cpu] = p->prio;
|
|
+
|
|
+ if (!__update_cpumasks_bitmap(cpu, &rq->queued_level, level,
|
|
+ &sched_rq_queued_masks[0],
|
|
+ &sched_rq_queued_masks_bitmap[0]))
|
|
+ return;
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ if (cpu == per_cpu(sched_sibling_cpu, cpu))
|
|
+ return;
|
|
+
|
|
+ if (SCHED_RQ_EMPTY == last_level) {
|
|
+ cpumask_andnot(&sched_cpu_sg_idle_mask, &sched_cpu_sg_idle_mask,
|
|
+ cpu_smt_mask(cpu));
|
|
+ } else if (SCHED_RQ_EMPTY == level) {
|
|
+ cpumask_t tmp;
|
|
+
|
|
+ cpumask_and(&tmp, cpu_smt_mask(cpu),
|
|
+ &sched_rq_queued_masks[SCHED_RQ_EMPTY]);
|
|
+ if (cpumask_equal(&tmp, cpu_smt_mask(cpu)))
|
|
+ cpumask_or(&sched_cpu_sg_idle_mask, cpu_smt_mask(cpu),
|
|
+ &sched_cpu_sg_idle_mask);
|
|
+ }
|
|
+
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+ if (level <= SCHED_RQ_IDLE && last_level > SCHED_RQ_IDLE) {
|
|
+ cpumask_clear_cpu(per_cpu(sched_sibling_cpu, cpu),
|
|
+ &sched_smt_supressed_mask);
|
|
+ update_sched_cpu_psg_mask(cpu);
|
|
+ resched_cpu_if_curr_is(per_cpu(sched_sibling_cpu, cpu), PRIO_LIMIT);
|
|
+ } else if (last_level <= SCHED_RQ_IDLE && level > SCHED_RQ_IDLE) {
|
|
+ cpumask_set_cpu(per_cpu(sched_sibling_cpu, cpu),
|
|
+ &sched_smt_supressed_mask);
|
|
+ update_sched_cpu_psg_mask(cpu);
|
|
+ resched_cpu_if_curr_is(per_cpu(sched_sibling_cpu, cpu), IDLE_PRIO);
|
|
+ }
|
|
+#endif /* CONFIG_SMT_NICE */
|
|
+#endif
|
|
+}
|
|
+
|
|
+static inline void update_sched_rq_pending_masks(struct rq *rq)
|
|
+{
|
|
+ unsigned long level;
|
|
+ struct task_struct *p = rq_second_queued_task(rq);
|
|
+
|
|
+ level = task_running_policy_level(p, rq);
|
|
+
|
|
+ __update_cpumasks_bitmap(cpu_of(rq), &rq->pending_level, level,
|
|
+ &sched_rq_pending_masks[0],
|
|
+ &sched_rq_pending_masks_bitmap[0]);
|
|
+}
|
|
+
|
|
+#else /* CONFIG_SMP */
|
|
+static inline void update_sched_rq_queued_masks(struct rq *rq) {}
|
|
+static inline void update_sched_rq_queued_masks_normal(struct rq *rq) {}
|
|
+static inline void update_sched_rq_pending_masks(struct rq *rq) {}
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_NO_HZ_FULL
|
|
+/*
|
|
+ * Tick may be needed by tasks in the runqueue depending on their policy and
|
|
+ * requirements. If tick is needed, lets send the target an IPI to kick it out
|
|
+ * of nohz mode if necessary.
|
|
+ */
|
|
+static inline void sched_update_tick_dependency(struct rq *rq)
|
|
+{
|
|
+ int cpu;
|
|
+
|
|
+ if (!tick_nohz_full_enabled())
|
|
+ return;
|
|
+
|
|
+ cpu = cpu_of(rq);
|
|
+
|
|
+ if (!tick_nohz_full_cpu(cpu))
|
|
+ return;
|
|
+
|
|
+ if (rq->nr_running < 2)
|
|
+ tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
|
|
+ else
|
|
+ tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
|
|
+}
|
|
+#else /* !CONFIG_NO_HZ_FULL */
|
|
+static inline void sched_update_tick_dependency(struct rq *rq) { }
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * Removing from the runqueue. Deleting a task from the skip list is done
|
|
+ * via the stored node reference in the task struct and does not require a full
|
|
+ * look up. Thus it occurs in O(k) time where k is the "level" of the list the
|
|
+ * task was stored at - usually < 4, max 16.
|
|
+ *
|
|
+ * Context: rq->lock
|
|
+ */
|
|
+static inline void dequeue_task(struct task_struct *p, struct rq *rq, int flags)
|
|
+{
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ WARN_ONCE(task_rq(p) != rq, "pds: dequeue task reside on cpu%d from cpu%d\n",
|
|
+ task_cpu(p), cpu_of(rq));
|
|
+ if (skiplist_del_init(&rq->sl_header, &p->sl_node)) {
|
|
+ update_sched_rq_queued_masks(rq);
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+ } else if (is_second_in_rq(p, rq))
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+ rq->nr_running--;
|
|
+
|
|
+ sched_update_tick_dependency(rq);
|
|
+ psi_dequeue(p, flags & DEQUEUE_SLEEP);
|
|
+
|
|
+ sched_info_dequeued(rq, p);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * To determine if it's safe for a task of SCHED_IDLE to actually run as
|
|
+ * an idle task, we ensure none of the following conditions are met.
|
|
+ */
|
|
+static inline bool idleprio_suitable(struct task_struct *p)
|
|
+{
|
|
+ return (!freezing(p) && !signal_pending(p) &&
|
|
+ !(task_contributes_to_load(p)) && !(p->flags & (PF_EXITING)));
|
|
+}
|
|
+
|
|
+/*
|
|
+ * pds_skiplist_random_level -- Returns a pseudo-random level number for skip
|
|
+ * list node which is used in PDS run queue.
|
|
+ *
|
|
+ * In current implementation, based on testing, the first 8 bits in microseconds
|
|
+ * of niffies are suitable for random level population.
|
|
+ * find_first_bit() is used to satisfy p = 0.5 between each levels, and there
|
|
+ * should be platform hardware supported instruction(known as ctz/clz) to speed
|
|
+ * up this function.
|
|
+ * The skiplist level for a task is populated when task is created and doesn't
|
|
+ * change in task's life time. When task is being inserted into run queue, this
|
|
+ * skiplist level is set to task's sl_node->level, the skiplist insert function
|
|
+ * may change it based on current level of the skip lsit.
|
|
+ */
|
|
+static inline int pds_skiplist_random_level(const struct task_struct *p)
|
|
+{
|
|
+ long unsigned int randseed;
|
|
+
|
|
+ /*
|
|
+ * 1. Some architectures don't have better than microsecond resolution
|
|
+ * so mask out ~microseconds as a factor of the random seed for skiplist
|
|
+ * insertion.
|
|
+ * 2. Use address of task structure pointer as another factor of the
|
|
+ * random seed for task burst forking scenario.
|
|
+ */
|
|
+ randseed = (task_rq(p)->clock ^ (long unsigned int)p) >> 10;
|
|
+
|
|
+ return find_first_bit(&randseed, NUM_SKIPLIST_LEVEL - 1);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * pds_skiplist_task_search -- search function used in PDS run queue skip list
|
|
+ * node insert operation.
|
|
+ * @it: iterator pointer to the node in the skip list
|
|
+ * @node: pointer to the skiplist_node to be inserted
|
|
+ *
|
|
+ * Returns true if key of @it is less or equal to key value of @node, otherwise
|
|
+ * false.
|
|
+ */
|
|
+static inline bool
|
|
+pds_skiplist_task_search(struct skiplist_node *it, struct skiplist_node *node)
|
|
+{
|
|
+ return (skiplist_entry(it, struct task_struct, sl_node)->priodl <=
|
|
+ skiplist_entry(node, struct task_struct, sl_node)->priodl);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Define the skip list insert function for PDS
|
|
+ */
|
|
+DEFINE_SKIPLIST_INSERT_FUNC(pds_skiplist_insert, pds_skiplist_task_search);
|
|
+
|
|
+/*
|
|
+ * Adding task to the runqueue.
|
|
+ *
|
|
+ * Context: rq->lock
|
|
+ */
|
|
+static inline void enqueue_task(struct task_struct *p, struct rq *rq, int flags)
|
|
+{
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ WARN_ONCE(task_rq(p) != rq, "pds: enqueue task reside on cpu%d to cpu%d\n",
|
|
+ task_cpu(p), cpu_of(rq));
|
|
+
|
|
+ p->sl_node.level = p->sl_level;
|
|
+ if (pds_skiplist_insert(&rq->sl_header, &p->sl_node)) {
|
|
+ update_sched_rq_queued_masks(rq);
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+ } else if (is_second_in_rq(p, rq))
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+ rq->nr_running++;
|
|
+
|
|
+ sched_update_tick_dependency(rq);
|
|
+
|
|
+ sched_info_queued(rq, p);
|
|
+ psi_enqueue(p, flags);
|
|
+
|
|
+ /*
|
|
+ * If in_iowait is set, the code below may not trigger any cpufreq
|
|
+ * utilization updates, so do it here explicitly with the IOWAIT flag
|
|
+ * passed.
|
|
+ */
|
|
+ if (p->in_iowait)
|
|
+ cpufreq_update_this_cpu(rq, SCHED_CPUFREQ_IOWAIT);
|
|
+}
|
|
+
|
|
+static inline void requeue_task(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ bool b_first, b_second;
|
|
+
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ WARN_ONCE(task_rq(p) != rq, "pds: cpu[%d] requeue task reside on cpu%d\n",
|
|
+ cpu_of(rq), task_cpu(p));
|
|
+
|
|
+ b_first = skiplist_del_init(&rq->sl_header, &p->sl_node);
|
|
+ b_second = is_second_in_rq(p, rq);
|
|
+
|
|
+ p->sl_node.level = p->sl_level;
|
|
+ if (pds_skiplist_insert(&rq->sl_header, &p->sl_node) || b_first) {
|
|
+ update_sched_rq_queued_masks(rq);
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+ } else if (is_second_in_rq(p, rq) || b_second)
|
|
+ update_sched_rq_pending_masks(rq);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * resched_curr - mark rq's current task 'to be rescheduled now'.
|
|
+ *
|
|
+ * On UP this means the setting of the need_resched flag, on SMP it
|
|
+ * might also involve a cross-CPU call to trigger the scheduler on
|
|
+ * the target CPU.
|
|
+ */
|
|
+void resched_curr(struct rq *rq)
|
|
+{
|
|
+ struct task_struct *curr = rq->curr;
|
|
+ int cpu;
|
|
+
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ if (test_tsk_need_resched(curr))
|
|
+ return;
|
|
+
|
|
+ cpu = cpu_of(rq);
|
|
+ if (cpu == smp_processor_id()) {
|
|
+ set_tsk_need_resched(curr);
|
|
+ set_preempt_need_resched();
|
|
+ return;
|
|
+ }
|
|
+
|
|
+ if (set_nr_and_not_polling(curr))
|
|
+ smp_send_reschedule(cpu);
|
|
+ else
|
|
+ trace_sched_wake_idle_without_ipi(cpu);
|
|
+}
|
|
+
|
|
+static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
|
|
+{
|
|
+ struct task_struct *curr = rq->curr;
|
|
+
|
|
+ if (curr->prio == PRIO_LIMIT)
|
|
+ resched_curr(rq);
|
|
+
|
|
+ if (task_running_idle(p))
|
|
+ return;
|
|
+
|
|
+ if (p->priodl < curr->priodl)
|
|
+ resched_curr(rq);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SCHED_HRTICK
|
|
+/*
|
|
+ * Use HR-timers to deliver accurate preemption points.
|
|
+ */
|
|
+
|
|
+static void hrtick_clear(struct rq *rq)
|
|
+{
|
|
+ if (hrtimer_active(&rq->hrtick_timer))
|
|
+ hrtimer_cancel(&rq->hrtick_timer);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * High-resolution timer tick.
|
|
+ * Runs from hardirq context with interrupts disabled.
|
|
+ */
|
|
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
|
|
+{
|
|
+ struct rq *rq = container_of(timer, struct rq, hrtick_timer);
|
|
+ struct task_struct *p;
|
|
+
|
|
+ WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
|
|
+
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ p = rq->curr;
|
|
+ p->time_slice = 0;
|
|
+ resched_curr(rq);
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+
|
|
+ return HRTIMER_NORESTART;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Use hrtick when:
|
|
+ * - enabled by features
|
|
+ * - hrtimer is actually high res
|
|
+ */
|
|
+static inline int hrtick_enabled(struct rq *rq)
|
|
+{
|
|
+ /**
|
|
+ * PDS doesn't support sched_feat yet
|
|
+ if (!sched_feat(HRTICK))
|
|
+ return 0;
|
|
+ */
|
|
+ if (!cpu_active(cpu_of(rq)))
|
|
+ return 0;
|
|
+ return hrtimer_is_hres_active(&rq->hrtick_timer);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+
|
|
+static void __hrtick_restart(struct rq *rq)
|
|
+{
|
|
+ struct hrtimer *timer = &rq->hrtick_timer;
|
|
+
|
|
+ hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * called from hardirq (IPI) context
|
|
+ */
|
|
+static void __hrtick_start(void *arg)
|
|
+{
|
|
+ struct rq *rq = arg;
|
|
+
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ __hrtick_restart(rq);
|
|
+ rq->hrtick_csd_pending = 0;
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Called to set the hrtick timer state.
|
|
+ *
|
|
+ * called with rq->lock held and irqs disabled
|
|
+ */
|
|
+void hrtick_start(struct rq *rq, u64 delay)
|
|
+{
|
|
+ struct hrtimer *timer = &rq->hrtick_timer;
|
|
+ ktime_t time;
|
|
+ s64 delta;
|
|
+
|
|
+ /*
|
|
+ * Don't schedule slices shorter than 10000ns, that just
|
|
+ * doesn't make sense and can cause timer DoS.
|
|
+ */
|
|
+ delta = max_t(s64, delay, 10000LL);
|
|
+ time = ktime_add_ns(timer->base->get_time(), delta);
|
|
+
|
|
+ hrtimer_set_expires(timer, time);
|
|
+
|
|
+ if (rq == this_rq()) {
|
|
+ __hrtick_restart(rq);
|
|
+ } else if (!rq->hrtick_csd_pending) {
|
|
+ smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
|
|
+ rq->hrtick_csd_pending = 1;
|
|
+ }
|
|
+}
|
|
+
|
|
+#else
|
|
+/*
|
|
+ * Called to set the hrtick timer state.
|
|
+ *
|
|
+ * called with rq->lock held and irqs disabled
|
|
+ */
|
|
+void hrtick_start(struct rq *rq, u64 delay)
|
|
+{
|
|
+ /*
|
|
+ * Don't schedule slices shorter than 10000ns, that just
|
|
+ * doesn't make sense. Rely on vruntime for fairness.
|
|
+ */
|
|
+ delay = max_t(u64, delay, 10000LL);
|
|
+ hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
|
|
+ HRTIMER_MODE_REL_PINNED_HARD);
|
|
+}
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+static void hrtick_rq_init(struct rq *rq)
|
|
+{
|
|
+#ifdef CONFIG_SMP
|
|
+ rq->hrtick_csd_pending = 0;
|
|
+
|
|
+ rq->hrtick_csd.flags = 0;
|
|
+ rq->hrtick_csd.func = __hrtick_start;
|
|
+ rq->hrtick_csd.info = rq;
|
|
+#endif
|
|
+
|
|
+ hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
|
|
+ rq->hrtick_timer.function = hrtick;
|
|
+}
|
|
+
|
|
+static inline int rq_dither(struct rq *rq)
|
|
+{
|
|
+ if ((rq->clock - rq->last_tick > HALF_JIFFY_NS) || hrtick_enabled(rq))
|
|
+ return 0;
|
|
+
|
|
+ return HALF_JIFFY_NS;
|
|
+}
|
|
+
|
|
+#else /* CONFIG_SCHED_HRTICK */
|
|
+static inline int hrtick_enabled(struct rq *rq)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static inline void hrtick_clear(struct rq *rq)
|
|
+{
|
|
+}
|
|
+
|
|
+static inline void hrtick_rq_init(struct rq *rq)
|
|
+{
|
|
+}
|
|
+
|
|
+static inline int rq_dither(struct rq *rq)
|
|
+{
|
|
+ return (rq->clock - rq->last_tick > HALF_JIFFY_NS)? 0:HALF_JIFFY_NS;
|
|
+}
|
|
+#endif /* CONFIG_SCHED_HRTICK */
|
|
+
|
|
+static inline int normal_prio(struct task_struct *p)
|
|
+{
|
|
+ static const int policy_to_prio[] = {
|
|
+ NORMAL_PRIO, /* SCHED_NORMAL */
|
|
+ 0, /* SCHED_FIFO */
|
|
+ 0, /* SCHED_RR */
|
|
+ IDLE_PRIO, /* SCHED_BATCH */
|
|
+ ISO_PRIO, /* SCHED_ISO */
|
|
+ IDLE_PRIO /* SCHED_IDLE */
|
|
+ };
|
|
+
|
|
+ if (task_has_rt_policy(p))
|
|
+ return MAX_RT_PRIO - 1 - p->rt_priority;
|
|
+ return policy_to_prio[p->policy];
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Calculate the current priority, i.e. the priority
|
|
+ * taken into account by the scheduler. This value might
|
|
+ * be boosted by RT tasks as it will be RT if the task got
|
|
+ * RT-boosted. If not then it returns p->normal_prio.
|
|
+ */
|
|
+static int effective_prio(struct task_struct *p)
|
|
+{
|
|
+ p->normal_prio = normal_prio(p);
|
|
+ /*
|
|
+ * If we are RT tasks or we were boosted to RT priority,
|
|
+ * keep the priority unchanged. Otherwise, update priority
|
|
+ * to the normal priority:
|
|
+ */
|
|
+ if (!rt_prio(p->prio))
|
|
+ return p->normal_prio;
|
|
+ return p->prio;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * activate_task - move a task to the runqueue.
|
|
+ *
|
|
+ * Context: rq->lock
|
|
+ */
|
|
+static void activate_task(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ if (task_contributes_to_load(p))
|
|
+ rq->nr_uninterruptible--;
|
|
+ enqueue_task(p, rq, ENQUEUE_WAKEUP);
|
|
+ p->on_rq = 1;
|
|
+ cpufreq_update_this_cpu(rq, 0);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * deactivate_task - remove a task from the runqueue.
|
|
+ *
|
|
+ * Context: rq->lock
|
|
+ */
|
|
+static inline void deactivate_task(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ if (task_contributes_to_load(p))
|
|
+ rq->nr_uninterruptible++;
|
|
+ dequeue_task(p, rq, DEQUEUE_SLEEP);
|
|
+ p->on_rq = 0;
|
|
+ cpufreq_update_this_cpu(rq, 0);
|
|
+}
|
|
+
|
|
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
|
|
+{
|
|
+#ifdef CONFIG_SMP
|
|
+ /*
|
|
+ * After ->cpu is set up to a new value, task_access_lock(p, ...) can be
|
|
+ * successfully executed on another CPU. We must ensure that updates of
|
|
+ * per-task data have been completed by this moment.
|
|
+ */
|
|
+ smp_wmb();
|
|
+
|
|
+#ifdef CONFIG_THREAD_INFO_IN_TASK
|
|
+ WRITE_ONCE(p->cpu, cpu);
|
|
+#else
|
|
+ WRITE_ONCE(task_thread_info(p)->cpu, cpu);
|
|
+#endif
|
|
+#endif
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
|
|
+{
|
|
+#ifdef CONFIG_SCHED_DEBUG
|
|
+ /*
|
|
+ * We should never call set_task_cpu() on a blocked task,
|
|
+ * ttwu() will sort out the placement.
|
|
+ */
|
|
+ WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
|
|
+ !p->on_rq);
|
|
+#ifdef CONFIG_LOCKDEP
|
|
+ /*
|
|
+ * The caller should hold either p->pi_lock or rq->lock, when changing
|
|
+ * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
|
|
+ *
|
|
+ * sched_move_task() holds both and thus holding either pins the cgroup,
|
|
+ * see task_group().
|
|
+ */
|
|
+ WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
|
|
+ lockdep_is_held(&task_rq(p)->lock)));
|
|
+#endif
|
|
+ /*
|
|
+ * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
|
|
+ */
|
|
+ WARN_ON_ONCE(!cpu_online(new_cpu));
|
|
+#endif
|
|
+ if (task_cpu(p) == new_cpu)
|
|
+ return;
|
|
+ trace_sched_migrate_task(p, new_cpu);
|
|
+ rseq_migrate(p);
|
|
+ perf_event_task_migrate(p);
|
|
+
|
|
+ __set_task_cpu(p, new_cpu);
|
|
+}
|
|
+
|
|
+static inline bool is_per_cpu_kthread(struct task_struct *p)
|
|
+{
|
|
+ return ((p->flags & PF_KTHREAD) && (1 == p->nr_cpus_allowed));
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
|
|
+ * __set_cpus_allowed_ptr() and select_fallback_rq().
|
|
+ */
|
|
+static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
|
|
+{
|
|
+ if (!cpumask_test_cpu(cpu, &p->cpus_mask))
|
|
+ return false;
|
|
+
|
|
+ if (is_per_cpu_kthread(p))
|
|
+ return cpu_online(cpu);
|
|
+
|
|
+ return cpu_active(cpu);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * This is how migration works:
|
|
+ *
|
|
+ * 1) we invoke migration_cpu_stop() on the target CPU using
|
|
+ * stop_one_cpu().
|
|
+ * 2) stopper starts to run (implicitly forcing the migrated thread
|
|
+ * off the CPU)
|
|
+ * 3) it checks whether the migrated task is still in the wrong runqueue.
|
|
+ * 4) if it's in the wrong runqueue then the migration thread removes
|
|
+ * it and puts it into the right queue.
|
|
+ * 5) stopper completes and stop_one_cpu() returns and the migration
|
|
+ * is done.
|
|
+ */
|
|
+
|
|
+/*
|
|
+ * detach_task() -- detach the task for the migration specified in @target_cpu
|
|
+ */
|
|
+static void detach_task(struct rq *rq, struct task_struct *p, int target_cpu)
|
|
+{
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ WRITE_ONCE(p->on_rq ,TASK_ON_RQ_MIGRATING);
|
|
+ if (task_contributes_to_load(p))
|
|
+ rq->nr_uninterruptible++;
|
|
+ dequeue_task(p, rq, 0);
|
|
+
|
|
+ set_task_cpu(p, target_cpu);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
|
|
+ */
|
|
+static void attach_task(struct rq *rq, struct task_struct *p)
|
|
+{
|
|
+ lockdep_assert_held(&rq->lock);
|
|
+
|
|
+ BUG_ON(task_rq(p) != rq);
|
|
+
|
|
+ if (task_contributes_to_load(p))
|
|
+ rq->nr_uninterruptible--;
|
|
+ enqueue_task(p, rq, 0);
|
|
+ p->on_rq = TASK_ON_RQ_QUEUED;
|
|
+ cpufreq_update_this_cpu(rq, 0);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * move_queued_task - move a queued task to new rq.
|
|
+ *
|
|
+ * Returns (locked) new rq. Old rq's lock is released.
|
|
+ */
|
|
+static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int
|
|
+ new_cpu)
|
|
+{
|
|
+ detach_task(rq, p, new_cpu);
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+
|
|
+ rq = cpu_rq(new_cpu);
|
|
+
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ update_rq_clock(rq);
|
|
+
|
|
+ attach_task(rq, p);
|
|
+
|
|
+ check_preempt_curr(rq, p);
|
|
+
|
|
+ return rq;
|
|
+}
|
|
+
|
|
+struct migration_arg {
|
|
+ struct task_struct *task;
|
|
+ int dest_cpu;
|
|
+};
|
|
+
|
|
+/*
|
|
+ * Move (not current) task off this CPU, onto the destination CPU. We're doing
|
|
+ * this because either it can't run here any more (set_cpus_allowed()
|
|
+ * away from this CPU, or CPU going down), or because we're
|
|
+ * attempting to rebalance this task on exec (sched_exec).
|
|
+ *
|
|
+ * So we race with normal scheduler movements, but that's OK, as long
|
|
+ * as the task is no longer on this CPU.
|
|
+ */
|
|
+static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int
|
|
+ dest_cpu)
|
|
+{
|
|
+ /* Affinity changed (again). */
|
|
+ if (!is_cpu_allowed(p, dest_cpu))
|
|
+ return rq;
|
|
+
|
|
+ update_rq_clock(rq);
|
|
+ return move_queued_task(rq, p, dest_cpu);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * migration_cpu_stop - this will be executed by a highprio stopper thread
|
|
+ * and performs thread migration by bumping thread off CPU then
|
|
+ * 'pushing' onto another runqueue.
|
|
+ */
|
|
+static int migration_cpu_stop(void *data)
|
|
+{
|
|
+ struct migration_arg *arg = data;
|
|
+ struct task_struct *p = arg->task;
|
|
+ struct rq *rq = this_rq();
|
|
+
|
|
+ /*
|
|
+ * The original target CPU might have gone down and we might
|
|
+ * be on another CPU but it doesn't matter.
|
|
+ */
|
|
+ local_irq_disable();
|
|
+
|
|
+ raw_spin_lock(&p->pi_lock);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ /*
|
|
+ * If task_rq(p) != rq, it cannot be migrated here, because we're
|
|
+ * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
|
|
+ * we're holding p->pi_lock.
|
|
+ */
|
|
+ if (task_rq(p) == rq)
|
|
+ if (task_on_rq_queued(p))
|
|
+ rq = __migrate_task(rq, p, arg->dest_cpu);
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock(&p->pi_lock);
|
|
+
|
|
+ local_irq_enable();
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static inline void
|
|
+set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
|
|
+{
|
|
+ cpumask_copy(&p->cpus_mask, new_mask);
|
|
+ p->nr_cpus_allowed = cpumask_weight(new_mask);
|
|
+}
|
|
+
|
|
+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
|
|
+{
|
|
+ set_cpus_allowed_common(p, new_mask);
|
|
+}
|
|
+#endif
|
|
+
|
|
+/* Enter with rq lock held. We know p is on the local CPU */
|
|
+static inline void __set_tsk_resched(struct task_struct *p)
|
|
+{
|
|
+ set_tsk_need_resched(p);
|
|
+ set_preempt_need_resched();
|
|
+}
|
|
+
|
|
+/**
|
|
+ * task_curr - is this task currently executing on a CPU?
|
|
+ * @p: the task in question.
|
|
+ *
|
|
+ * Return: 1 if the task is currently executing. 0 otherwise.
|
|
+ */
|
|
+inline int task_curr(const struct task_struct *p)
|
|
+{
|
|
+ return cpu_curr(task_cpu(p)) == p;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+/*
|
|
+ * wait_task_inactive - wait for a thread to unschedule.
|
|
+ *
|
|
+ * If @match_state is nonzero, it's the @p->state value just checked and
|
|
+ * not expected to change. If it changes, i.e. @p might have woken up,
|
|
+ * then return zero. When we succeed in waiting for @p to be off its CPU,
|
|
+ * we return a positive number (its total switch count). If a second call
|
|
+ * a short while later returns the same number, the caller can be sure that
|
|
+ * @p has remained unscheduled the whole time.
|
|
+ *
|
|
+ * The caller must ensure that the task *will* unschedule sometime soon,
|
|
+ * else this function might spin for a *long* time. This function can't
|
|
+ * be called with interrupts off, or it may introduce deadlock with
|
|
+ * smp_call_function() if an IPI is sent by the same process we are
|
|
+ * waiting to become inactive.
|
|
+ */
|
|
+unsigned long wait_task_inactive(struct task_struct *p, long match_state)
|
|
+{
|
|
+ unsigned long flags;
|
|
+ bool running, on_rq;
|
|
+ unsigned long ncsw;
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+
|
|
+ for (;;) {
|
|
+ rq = task_rq(p);
|
|
+
|
|
+ /*
|
|
+ * If the task is actively running on another CPU
|
|
+ * still, just relax and busy-wait without holding
|
|
+ * any locks.
|
|
+ *
|
|
+ * NOTE! Since we don't hold any locks, it's not
|
|
+ * even sure that "rq" stays as the right runqueue!
|
|
+ * But we don't care, since this will return false
|
|
+ * if the runqueue has changed and p is actually now
|
|
+ * running somewhere else!
|
|
+ */
|
|
+ while (task_running(p) && p == rq->curr) {
|
|
+ if (match_state && unlikely(p->state != match_state))
|
|
+ return 0;
|
|
+ cpu_relax();
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * Ok, time to look more closely! We need the rq
|
|
+ * lock now, to be *sure*. If we're wrong, we'll
|
|
+ * just go back and repeat.
|
|
+ */
|
|
+ task_access_lock_irqsave(p, &lock, &flags);
|
|
+ trace_sched_wait_task(p);
|
|
+ running = task_running(p);
|
|
+ on_rq = p->on_rq;
|
|
+ ncsw = 0;
|
|
+ if (!match_state || p->state == match_state)
|
|
+ ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
|
|
+ task_access_unlock_irqrestore(p, lock, &flags);
|
|
+
|
|
+ /*
|
|
+ * If it changed from the expected state, bail out now.
|
|
+ */
|
|
+ if (unlikely(!ncsw))
|
|
+ break;
|
|
+
|
|
+ /*
|
|
+ * Was it really running after all now that we
|
|
+ * checked with the proper locks actually held?
|
|
+ *
|
|
+ * Oops. Go back and try again..
|
|
+ */
|
|
+ if (unlikely(running)) {
|
|
+ cpu_relax();
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * It's not enough that it's not actively running,
|
|
+ * it must be off the runqueue _entirely_, and not
|
|
+ * preempted!
|
|
+ *
|
|
+ * So if it was still runnable (but just not actively
|
|
+ * running right now), it's preempted, and we should
|
|
+ * yield - it could be a while.
|
|
+ */
|
|
+ if (unlikely(on_rq)) {
|
|
+ ktime_t to = NSEC_PER_SEC / HZ;
|
|
+
|
|
+ set_current_state(TASK_UNINTERRUPTIBLE);
|
|
+ schedule_hrtimeout(&to, HRTIMER_MODE_REL);
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * Ahh, all good. It wasn't running, and it wasn't
|
|
+ * runnable, which means that it will never become
|
|
+ * running in the future either. We're all done!
|
|
+ */
|
|
+ break;
|
|
+ }
|
|
+
|
|
+ return ncsw;
|
|
+}
|
|
+
|
|
+/***
|
|
+ * kick_process - kick a running thread to enter/exit the kernel
|
|
+ * @p: the to-be-kicked thread
|
|
+ *
|
|
+ * Cause a process which is running on another CPU to enter
|
|
+ * kernel-mode, without any delay. (to get signals handled.)
|
|
+ *
|
|
+ * NOTE: this function doesn't have to take the runqueue lock,
|
|
+ * because all it wants to ensure is that the remote task enters
|
|
+ * the kernel. If the IPI races and the task has been migrated
|
|
+ * to another CPU then no harm is done and the purpose has been
|
|
+ * achieved as well.
|
|
+ */
|
|
+void kick_process(struct task_struct *p)
|
|
+{
|
|
+ int cpu;
|
|
+
|
|
+ preempt_disable();
|
|
+ cpu = task_cpu(p);
|
|
+ if ((cpu != smp_processor_id()) && task_curr(p))
|
|
+ smp_send_reschedule(cpu);
|
|
+ preempt_enable();
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(kick_process);
|
|
+
|
|
+/*
|
|
+ * ->cpus_mask is protected by both rq->lock and p->pi_lock
|
|
+ *
|
|
+ * A few notes on cpu_active vs cpu_online:
|
|
+ *
|
|
+ * - cpu_active must be a subset of cpu_online
|
|
+ *
|
|
+ * - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
|
|
+ * see __set_cpus_allowed_ptr(). At this point the newly online
|
|
+ * CPU isn't yet part of the sched domains, and balancing will not
|
|
+ * see it.
|
|
+ *
|
|
+ * - on cpu-down we clear cpu_active() to mask the sched domains and
|
|
+ * avoid the load balancer to place new tasks on the to be removed
|
|
+ * CPU. Existing tasks will remain running there and will be taken
|
|
+ * off.
|
|
+ *
|
|
+ * This means that fallback selection must not select !active CPUs.
|
|
+ * And can assume that any active CPU must be online. Conversely
|
|
+ * select_task_rq() below may allow selection of !active CPUs in order
|
|
+ * to satisfy the above rules.
|
|
+ */
|
|
+static int select_fallback_rq(int cpu, struct task_struct *p)
|
|
+{
|
|
+ int nid = cpu_to_node(cpu);
|
|
+ const struct cpumask *nodemask = NULL;
|
|
+ enum { cpuset, possible, fail } state = cpuset;
|
|
+ int dest_cpu;
|
|
+
|
|
+ /*
|
|
+ * If the node that the CPU is on has been offlined, cpu_to_node()
|
|
+ * will return -1. There is no CPU on the node, and we should
|
|
+ * select the CPU on the other node.
|
|
+ */
|
|
+ if (nid != -1) {
|
|
+ nodemask = cpumask_of_node(nid);
|
|
+
|
|
+ /* Look for allowed, online CPU in same node. */
|
|
+ for_each_cpu(dest_cpu, nodemask) {
|
|
+ if (!cpu_active(dest_cpu))
|
|
+ continue;
|
|
+ if (cpumask_test_cpu(dest_cpu, &p->cpus_mask))
|
|
+ return dest_cpu;
|
|
+ }
|
|
+ }
|
|
+
|
|
+ for (;;) {
|
|
+ /* Any allowed, online CPU? */
|
|
+ for_each_cpu(dest_cpu, &p->cpus_mask) {
|
|
+ if (!is_cpu_allowed(p, dest_cpu))
|
|
+ continue;
|
|
+ goto out;
|
|
+ }
|
|
+
|
|
+ /* No more Mr. Nice Guy. */
|
|
+ switch (state) {
|
|
+ case cpuset:
|
|
+ if (IS_ENABLED(CONFIG_CPUSETS)) {
|
|
+ cpuset_cpus_allowed_fallback(p);
|
|
+ state = possible;
|
|
+ break;
|
|
+ }
|
|
+ /* Fall-through */
|
|
+ case possible:
|
|
+ do_set_cpus_allowed(p, cpu_possible_mask);
|
|
+ state = fail;
|
|
+ break;
|
|
+
|
|
+ case fail:
|
|
+ BUG();
|
|
+ break;
|
|
+ }
|
|
+ }
|
|
+
|
|
+out:
|
|
+ if (state != cpuset) {
|
|
+ /*
|
|
+ * Don't tell them about moving exiting tasks or
|
|
+ * kernel threads (both mm NULL), since they never
|
|
+ * leave kernel.
|
|
+ */
|
|
+ if (p->mm && printk_ratelimit()) {
|
|
+ printk_deferred("process %d (%s) no longer affine to cpu%d\n",
|
|
+ task_pid_nr(p), p->comm, cpu);
|
|
+ }
|
|
+ }
|
|
+
|
|
+ return dest_cpu;
|
|
+}
|
|
+
|
|
+static inline int best_mask_cpu(int cpu, const cpumask_t *cpumask)
|
|
+{
|
|
+ cpumask_t *mask;
|
|
+
|
|
+ if (cpumask_test_cpu(cpu, cpumask))
|
|
+ return cpu;
|
|
+
|
|
+ mask = &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[0]);
|
|
+ while ((cpu = cpumask_any_and(cpumask, mask)) >= nr_cpu_ids)
|
|
+ mask++;
|
|
+
|
|
+ return cpu;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * task_preemptible_rq - return the rq which the given task can preempt on
|
|
+ * @p: task wants to preempt CPU
|
|
+ * @only_preempt_low_policy: indicate only preempt rq running low policy than @p
|
|
+ */
|
|
+static inline int
|
|
+task_preemptible_rq_idle(struct task_struct *p, cpumask_t *chk_mask)
|
|
+{
|
|
+ cpumask_t tmp;
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ if (cpumask_and(&tmp, chk_mask, &sched_cpu_sg_idle_mask))
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+ /* Only ttwu on cpu which is not smt supressed */
|
|
+ if (cpumask_andnot(&tmp, chk_mask, &sched_smt_supressed_mask)) {
|
|
+ cpumask_t t;
|
|
+ if (cpumask_and(&t, &tmp, &sched_rq_queued_masks[SCHED_RQ_EMPTY]))
|
|
+ return best_mask_cpu(task_cpu(p), &t);
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+ }
|
|
+#endif
|
|
+
|
|
+ if (cpumask_and(&tmp, chk_mask, &sched_rq_queued_masks[SCHED_RQ_EMPTY]))
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+ return best_mask_cpu(task_cpu(p), chk_mask);
|
|
+}
|
|
+
|
|
+static inline int
|
|
+task_preemptible_rq(struct task_struct *p, cpumask_t *chk_mask,
|
|
+ int preempt_level)
|
|
+{
|
|
+ cpumask_t tmp;
|
|
+ int level;
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+ if (cpumask_and(&tmp, chk_mask, &sched_cpu_psg_mask))
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+#else
|
|
+ if (cpumask_and(&tmp, chk_mask, &sched_cpu_sg_idle_mask))
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+#endif
|
|
+#endif
|
|
+
|
|
+ level = find_first_bit(sched_rq_queued_masks_bitmap,
|
|
+ NR_SCHED_RQ_QUEUED_LEVEL);
|
|
+
|
|
+ while (level < preempt_level) {
|
|
+ if (cpumask_and(&tmp, chk_mask, &sched_rq_queued_masks[level]))
|
|
+ return best_mask_cpu(task_cpu(p), &tmp);
|
|
+
|
|
+ level = find_next_bit(sched_rq_queued_masks_bitmap,
|
|
+ NR_SCHED_RQ_QUEUED_LEVEL,
|
|
+ level + 1);
|
|
+ }
|
|
+
|
|
+ if (unlikely(SCHED_RQ_RT == level &&
|
|
+ level == preempt_level &&
|
|
+ cpumask_and(&tmp, chk_mask,
|
|
+ &sched_rq_queued_masks[SCHED_RQ_RT]))) {
|
|
+ unsigned int cpu;
|
|
+
|
|
+ for_each_cpu (cpu, &tmp)
|
|
+ if (p->prio < sched_rq_prio[cpu])
|
|
+ return cpu;
|
|
+ }
|
|
+
|
|
+ return best_mask_cpu(task_cpu(p), chk_mask);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * wake flags
|
|
+ */
|
|
+#define WF_SYNC 0x01 /* waker goes to sleep after wakeup */
|
|
+#define WF_FORK 0x02 /* child wakeup after fork */
|
|
+#define WF_MIGRATED 0x04 /* internal use, task got migrated */
|
|
+
|
|
+static inline int select_task_rq(struct task_struct *p)
|
|
+{
|
|
+ cpumask_t chk_mask;
|
|
+
|
|
+ if (unlikely(!cpumask_and(&chk_mask, &p->cpus_mask, cpu_online_mask)))
|
|
+ return select_fallback_rq(task_cpu(p), p);
|
|
+
|
|
+ /* Check IDLE tasks suitable to run normal priority */
|
|
+ if (idleprio_task(p)) {
|
|
+ if (idleprio_suitable(p)) {
|
|
+ p->prio = p->normal_prio;
|
|
+ update_task_priodl(p);
|
|
+ return task_preemptible_rq_idle(p, &chk_mask);
|
|
+ }
|
|
+ p->prio = NORMAL_PRIO;
|
|
+ update_task_priodl(p);
|
|
+ }
|
|
+
|
|
+ return task_preemptible_rq(p, &chk_mask,
|
|
+ task_running_policy_level(p, this_rq()));
|
|
+}
|
|
+#else /* CONFIG_SMP */
|
|
+static inline int select_task_rq(struct task_struct *p)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+static void
|
|
+ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
|
|
+{
|
|
+ struct rq *rq;
|
|
+
|
|
+ if (!schedstat_enabled())
|
|
+ return;
|
|
+
|
|
+ rq= this_rq();
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ if (cpu == rq->cpu)
|
|
+ __schedstat_inc(rq->ttwu_local);
|
|
+ else {
|
|
+ /** PDS ToDo:
|
|
+ * How to do ttwu_wake_remote
|
|
+ */
|
|
+ }
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+ __schedstat_inc(rq->ttwu_count);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Mark the task runnable and perform wakeup-preemption.
|
|
+ */
|
|
+static inline void
|
|
+ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
|
|
+{
|
|
+ p->state = TASK_RUNNING;
|
|
+ trace_sched_wakeup(p);
|
|
+}
|
|
+
|
|
+static inline void
|
|
+ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
|
|
+{
|
|
+#ifdef CONFIG_SMP
|
|
+ if (p->sched_contributes_to_load)
|
|
+ rq->nr_uninterruptible--;
|
|
+#endif
|
|
+
|
|
+ activate_task(p, rq);
|
|
+ ttwu_do_wakeup(rq, p, 0);
|
|
+}
|
|
+
|
|
+static int ttwu_remote(struct task_struct *p, int wake_flags)
|
|
+{
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+ int ret = 0;
|
|
+
|
|
+ rq = __task_access_lock(p, &lock);
|
|
+ if (task_on_rq_queued(p)) {
|
|
+ ttwu_do_wakeup(rq, p, wake_flags);
|
|
+ ret = 1;
|
|
+ }
|
|
+ __task_access_unlock(p, lock);
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Notes on Program-Order guarantees on SMP systems.
|
|
+ *
|
|
+ * MIGRATION
|
|
+ *
|
|
+ * The basic program-order guarantee on SMP systems is that when a task [t]
|
|
+ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
|
|
+ * execution on its new CPU [c1].
|
|
+ *
|
|
+ * For migration (of runnable tasks) this is provided by the following means:
|
|
+ *
|
|
+ * A) UNLOCK of the rq(c0)->lock scheduling out task t
|
|
+ * B) migration for t is required to synchronize *both* rq(c0)->lock and
|
|
+ * rq(c1)->lock (if not at the same time, then in that order).
|
|
+ * C) LOCK of the rq(c1)->lock scheduling in task
|
|
+ *
|
|
+ * Transitivity guarantees that B happens after A and C after B.
|
|
+ * Note: we only require RCpc transitivity.
|
|
+ * Note: the CPU doing B need not be c0 or c1
|
|
+ *
|
|
+ * Example:
|
|
+ *
|
|
+ * CPU0 CPU1 CPU2
|
|
+ *
|
|
+ * LOCK rq(0)->lock
|
|
+ * sched-out X
|
|
+ * sched-in Y
|
|
+ * UNLOCK rq(0)->lock
|
|
+ *
|
|
+ * LOCK rq(0)->lock // orders against CPU0
|
|
+ * dequeue X
|
|
+ * UNLOCK rq(0)->lock
|
|
+ *
|
|
+ * LOCK rq(1)->lock
|
|
+ * enqueue X
|
|
+ * UNLOCK rq(1)->lock
|
|
+ *
|
|
+ * LOCK rq(1)->lock // orders against CPU2
|
|
+ * sched-out Z
|
|
+ * sched-in X
|
|
+ * UNLOCK rq(1)->lock
|
|
+ *
|
|
+ *
|
|
+ * BLOCKING -- aka. SLEEP + WAKEUP
|
|
+ *
|
|
+ * For blocking we (obviously) need to provide the same guarantee as for
|
|
+ * migration. However the means are completely different as there is no lock
|
|
+ * chain to provide order. Instead we do:
|
|
+ *
|
|
+ * 1) smp_store_release(X->on_cpu, 0)
|
|
+ * 2) smp_cond_load_acquire(!X->on_cpu)
|
|
+ *
|
|
+ * Example:
|
|
+ *
|
|
+ * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule)
|
|
+ *
|
|
+ * LOCK rq(0)->lock LOCK X->pi_lock
|
|
+ * dequeue X
|
|
+ * sched-out X
|
|
+ * smp_store_release(X->on_cpu, 0);
|
|
+ *
|
|
+ * smp_cond_load_acquire(&X->on_cpu, !VAL);
|
|
+ * X->state = WAKING
|
|
+ * set_task_cpu(X,2)
|
|
+ *
|
|
+ * LOCK rq(2)->lock
|
|
+ * enqueue X
|
|
+ * X->state = RUNNING
|
|
+ * UNLOCK rq(2)->lock
|
|
+ *
|
|
+ * LOCK rq(2)->lock // orders against CPU1
|
|
+ * sched-out Z
|
|
+ * sched-in X
|
|
+ * UNLOCK rq(2)->lock
|
|
+ *
|
|
+ * UNLOCK X->pi_lock
|
|
+ * UNLOCK rq(0)->lock
|
|
+ *
|
|
+ *
|
|
+ * However; for wakeups there is a second guarantee we must provide, namely we
|
|
+ * must observe the state that lead to our wakeup. That is, not only must our
|
|
+ * task observe its own prior state, it must also observe the stores prior to
|
|
+ * its wakeup.
|
|
+ *
|
|
+ * This means that any means of doing remote wakeups must order the CPU doing
|
|
+ * the wakeup against the CPU the task is going to end up running on. This,
|
|
+ * however, is already required for the regular Program-Order guarantee above,
|
|
+ * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire).
|
|
+ *
|
|
+ */
|
|
+
|
|
+/***
|
|
+ * try_to_wake_up - wake up a thread
|
|
+ * @p: the thread to be awakened
|
|
+ * @state: the mask of task states that can be woken
|
|
+ * @wake_flags: wake modifier flags (WF_*)
|
|
+ *
|
|
+ * Put it on the run-queue if it's not already there. The "current"
|
|
+ * thread is always on the run-queue (except when the actual
|
|
+ * re-schedule is in progress), and as such you're allowed to do
|
|
+ * the simpler "current->state = TASK_RUNNING" to mark yourself
|
|
+ * runnable without the overhead of this.
|
|
+ *
|
|
+ * Return: %true if @p was woken up, %false if it was already running.
|
|
+ * or @state didn't match @p's state.
|
|
+ */
|
|
+static int try_to_wake_up(struct task_struct *p, unsigned int state,
|
|
+ int wake_flags)
|
|
+{
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+ int cpu, success = 0;
|
|
+
|
|
+ /*
|
|
+ * If we are going to wake up a thread waiting for CONDITION we
|
|
+ * need to ensure that CONDITION=1 done by the caller can not be
|
|
+ * reordered with p->state check below. This pairs with mb() in
|
|
+ * set_current_state() the waiting thread does.
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+ smp_mb__after_spinlock();
|
|
+ if (!(p->state & state))
|
|
+ goto out;
|
|
+
|
|
+ trace_sched_waking(p);
|
|
+
|
|
+ /* We're going to change ->state: */
|
|
+ success = 1;
|
|
+ cpu = task_cpu(p);
|
|
+
|
|
+ /*
|
|
+ * Ensure we load p->on_rq _after_ p->state, otherwise it would
|
|
+ * be possible to, falsely, observe p->on_rq == 0 and get stuck
|
|
+ * in smp_cond_load_acquire() below.
|
|
+ *
|
|
+ * sched_ttwu_pending() try_to_wake_up()
|
|
+ * STORE p->on_rq = 1 LOAD p->state
|
|
+ * UNLOCK rq->lock
|
|
+ *
|
|
+ * __schedule() (switch to task 'p')
|
|
+ * LOCK rq->lock smp_rmb();
|
|
+ * smp_mb__after_spinlock();
|
|
+ * UNLOCK rq->lock
|
|
+ *
|
|
+ * [task p]
|
|
+ * STORE p->state = UNINTERRUPTIBLE LOAD p->on_rq
|
|
+ *
|
|
+ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
|
|
+ * __schedule(). See the comment for smp_mb__after_spinlock().
|
|
+ */
|
|
+ smp_rmb();
|
|
+ if (p->on_rq && ttwu_remote(p, wake_flags))
|
|
+ goto stat;
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ /*
|
|
+ * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
|
|
+ * possible to, falsely, observe p->on_cpu == 0.
|
|
+ *
|
|
+ * One must be running (->on_cpu == 1) in order to remove oneself
|
|
+ * from the runqueue.
|
|
+ *
|
|
+ * __schedule() (switch to task 'p') try_to_wake_up()
|
|
+ * STORE p->on_cpu = 1 LOAD p->on_rq
|
|
+ * UNLOCK rq->lock
|
|
+ *
|
|
+ * __schedule() (put 'p' to sleep)
|
|
+ * LOCK rq->lock smp_rmb();
|
|
+ * smp_mb__after_spinlock();
|
|
+ * STORE p->on_rq = 0 LOAD p->on_cpu
|
|
+ *
|
|
+ * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
|
|
+ * __schedule(). See the comment for smp_mb__after_spinlock().
|
|
+ */
|
|
+ smp_rmb();
|
|
+
|
|
+ /*
|
|
+ * If the owning (remote) CPU is still in the middle of schedule() with
|
|
+ * this task as prev, wait until its done referencing the task.
|
|
+ *
|
|
+ * Pairs with the smp_store_release() in finish_task().
|
|
+ *
|
|
+ * This ensures that tasks getting woken will be fully ordered against
|
|
+ * their previous state and preserve Program Order.
|
|
+ */
|
|
+ smp_cond_load_acquire(&p->on_cpu, !VAL);
|
|
+
|
|
+ p->sched_contributes_to_load = !!task_contributes_to_load(p);
|
|
+ p->state = TASK_WAKING;
|
|
+
|
|
+ if (p->in_iowait) {
|
|
+ delayacct_blkio_end(p);
|
|
+ atomic_dec(&task_rq(p)->nr_iowait);
|
|
+ }
|
|
+
|
|
+ if (SCHED_ISO == p->policy && ISO_PRIO != p->prio) {
|
|
+ p->prio = ISO_PRIO;
|
|
+ p->deadline = 0UL;
|
|
+ update_task_priodl(p);
|
|
+ }
|
|
+
|
|
+ cpu = select_task_rq(p);
|
|
+
|
|
+ if (cpu != task_cpu(p)) {
|
|
+ wake_flags |= WF_MIGRATED;
|
|
+ psi_ttwu_dequeue(p);
|
|
+ set_task_cpu(p, cpu);
|
|
+ }
|
|
+#else /* CONFIG_SMP */
|
|
+ if (p->in_iowait) {
|
|
+ delayacct_blkio_end(p);
|
|
+ atomic_dec(&task_rq(p)->nr_iowait);
|
|
+ }
|
|
+#endif
|
|
+
|
|
+ rq = cpu_rq(cpu);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+
|
|
+ update_rq_clock(rq);
|
|
+ ttwu_do_activate(rq, p, wake_flags);
|
|
+ check_preempt_curr(rq, p);
|
|
+
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+
|
|
+stat:
|
|
+ ttwu_stat(p, cpu, wake_flags);
|
|
+out:
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+
|
|
+ return success;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * wake_up_process - Wake up a specific process
|
|
+ * @p: The process to be woken up.
|
|
+ *
|
|
+ * Attempt to wake up the nominated process and move it to the set of runnable
|
|
+ * processes.
|
|
+ *
|
|
+ * Return: 1 if the process was woken up, 0 if it was already running.
|
|
+ *
|
|
+ * This function executes a full memory barrier before accessing the task state.
|
|
+ */
|
|
+int wake_up_process(struct task_struct *p)
|
|
+{
|
|
+ return try_to_wake_up(p, TASK_NORMAL, 0);
|
|
+}
|
|
+EXPORT_SYMBOL(wake_up_process);
|
|
+
|
|
+int wake_up_state(struct task_struct *p, unsigned int state)
|
|
+{
|
|
+ return try_to_wake_up(p, state, 0);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Perform scheduler related setup for a newly forked process p.
|
|
+ * p is forked by current.
|
|
+ */
|
|
+int sched_fork(unsigned long __maybe_unused clone_flags, struct task_struct *p)
|
|
+{
|
|
+ unsigned long flags;
|
|
+ int cpu = get_cpu();
|
|
+ struct rq *rq = this_rq();
|
|
+
|
|
+#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
+ INIT_HLIST_HEAD(&p->preempt_notifiers);
|
|
+#endif
|
|
+ /* Should be reset in fork.c but done here for ease of PDS patching */
|
|
+ p->on_cpu =
|
|
+ p->on_rq =
|
|
+ p->utime =
|
|
+ p->stime =
|
|
+ p->sched_time = 0;
|
|
+
|
|
+ p->sl_level = pds_skiplist_random_level(p);
|
|
+ INIT_SKIPLIST_NODE(&p->sl_node);
|
|
+
|
|
+#ifdef CONFIG_COMPACTION
|
|
+ p->capture_control = NULL;
|
|
+#endif
|
|
+
|
|
+ /*
|
|
+ * We mark the process as NEW here. This guarantees that
|
|
+ * nobody will actually run it, and a signal or other external
|
|
+ * event cannot wake it up and insert it on the runqueue either.
|
|
+ */
|
|
+ p->state = TASK_NEW;
|
|
+
|
|
+ /*
|
|
+ * Make sure we do not leak PI boosting priority to the child.
|
|
+ */
|
|
+ p->prio = current->normal_prio;
|
|
+
|
|
+ /*
|
|
+ * Revert to default priority/policy on fork if requested.
|
|
+ */
|
|
+ if (unlikely(p->sched_reset_on_fork)) {
|
|
+ if (task_has_rt_policy(p)) {
|
|
+ p->policy = SCHED_NORMAL;
|
|
+ p->static_prio = NICE_TO_PRIO(0);
|
|
+ p->rt_priority = 0;
|
|
+ } else if (PRIO_TO_NICE(p->static_prio) < 0)
|
|
+ p->static_prio = NICE_TO_PRIO(0);
|
|
+
|
|
+ p->prio = p->normal_prio = normal_prio(p);
|
|
+
|
|
+ /*
|
|
+ * We don't need the reset flag anymore after the fork. It has
|
|
+ * fulfilled its duty:
|
|
+ */
|
|
+ p->sched_reset_on_fork = 0;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * Share the timeslice between parent and child, thus the
|
|
+ * total amount of pending timeslices in the system doesn't change,
|
|
+ * resulting in more scheduling fairness.
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ rq->curr->time_slice /= 2;
|
|
+ p->time_slice = rq->curr->time_slice;
|
|
+#ifdef CONFIG_SCHED_HRTICK
|
|
+ hrtick_start(rq, US_TO_NS(rq->curr->time_slice));
|
|
+#endif
|
|
+
|
|
+ if (p->time_slice < RESCHED_US) {
|
|
+ update_rq_clock(rq);
|
|
+ time_slice_expired(p, rq);
|
|
+ resched_curr(rq);
|
|
+ } else
|
|
+ update_task_priodl(p);
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+
|
|
+ /*
|
|
+ * The child is not yet in the pid-hash so no cgroup attach races,
|
|
+ * and the cgroup is pinned to this child due to cgroup_fork()
|
|
+ * is ran before sched_fork().
|
|
+ *
|
|
+ * Silence PROVE_RCU.
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+ /*
|
|
+ * We're setting the CPU for the first time, we don't migrate,
|
|
+ * so use __set_task_cpu().
|
|
+ */
|
|
+ __set_task_cpu(p, cpu);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+
|
|
+#ifdef CONFIG_SCHED_INFO
|
|
+ if (unlikely(sched_info_on()))
|
|
+ memset(&p->sched_info, 0, sizeof(p->sched_info));
|
|
+#endif
|
|
+ init_task_preempt_count(p);
|
|
+
|
|
+ put_cpu();
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SCHEDSTATS
|
|
+
|
|
+DEFINE_STATIC_KEY_FALSE(sched_schedstats);
|
|
+static bool __initdata __sched_schedstats = false;
|
|
+
|
|
+static void set_schedstats(bool enabled)
|
|
+{
|
|
+ if (enabled)
|
|
+ static_branch_enable(&sched_schedstats);
|
|
+ else
|
|
+ static_branch_disable(&sched_schedstats);
|
|
+}
|
|
+
|
|
+void force_schedstat_enabled(void)
|
|
+{
|
|
+ if (!schedstat_enabled()) {
|
|
+ pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
|
|
+ static_branch_enable(&sched_schedstats);
|
|
+ }
|
|
+}
|
|
+
|
|
+static int __init setup_schedstats(char *str)
|
|
+{
|
|
+ int ret = 0;
|
|
+ if (!str)
|
|
+ goto out;
|
|
+
|
|
+ /*
|
|
+ * This code is called before jump labels have been set up, so we can't
|
|
+ * change the static branch directly just yet. Instead set a temporary
|
|
+ * variable so init_schedstats() can do it later.
|
|
+ */
|
|
+ if (!strcmp(str, "enable")) {
|
|
+ __sched_schedstats = true;
|
|
+ ret = 1;
|
|
+ } else if (!strcmp(str, "disable")) {
|
|
+ __sched_schedstats = false;
|
|
+ ret = 1;
|
|
+ }
|
|
+out:
|
|
+ if (!ret)
|
|
+ pr_warn("Unable to parse schedstats=\n");
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+__setup("schedstats=", setup_schedstats);
|
|
+
|
|
+static void __init init_schedstats(void)
|
|
+{
|
|
+ set_schedstats(__sched_schedstats);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_PROC_SYSCTL
|
|
+int sysctl_schedstats(struct ctl_table *table, int write,
|
|
+ void __user *buffer, size_t *lenp, loff_t *ppos)
|
|
+{
|
|
+ struct ctl_table t;
|
|
+ int err;
|
|
+ int state = static_branch_likely(&sched_schedstats);
|
|
+
|
|
+ if (write && !capable(CAP_SYS_ADMIN))
|
|
+ return -EPERM;
|
|
+
|
|
+ t = *table;
|
|
+ t.data = &state;
|
|
+ err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
|
|
+ if (err < 0)
|
|
+ return err;
|
|
+ if (write)
|
|
+ set_schedstats(state);
|
|
+ return err;
|
|
+}
|
|
+#endif /* CONFIG_PROC_SYSCTL */
|
|
+#else /* !CONFIG_SCHEDSTATS */
|
|
+static inline void init_schedstats(void) {}
|
|
+#endif /* CONFIG_SCHEDSTATS */
|
|
+
|
|
+/*
|
|
+ * wake_up_new_task - wake up a newly created task for the first time.
|
|
+ *
|
|
+ * This function will do some initial scheduler statistics housekeeping
|
|
+ * that must be done for every newly created context, then puts the task
|
|
+ * on the runqueue and wakes it.
|
|
+ */
|
|
+void wake_up_new_task(struct task_struct *p)
|
|
+{
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+
|
|
+ p->state = TASK_RUNNING;
|
|
+
|
|
+ rq = cpu_rq(select_task_rq(p));
|
|
+#ifdef CONFIG_SMP
|
|
+ /*
|
|
+ * Fork balancing, do it here and not earlier because:
|
|
+ * - cpus_mask can change in the fork path
|
|
+ * - any previously selected CPU might disappear through hotplug
|
|
+ * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
|
|
+ * as we're not fully set-up yet.
|
|
+ */
|
|
+ __set_task_cpu(p, cpu_of(rq));
|
|
+#endif
|
|
+
|
|
+ raw_spin_lock(&rq->lock);
|
|
+
|
|
+ update_rq_clock(rq);
|
|
+ activate_task(p, rq);
|
|
+ trace_sched_wakeup_new(p);
|
|
+ check_preempt_curr(rq, p);
|
|
+
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_PREEMPT_NOTIFIERS
|
|
+
|
|
+static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
|
|
+
|
|
+void preempt_notifier_inc(void)
|
|
+{
|
|
+ static_branch_inc(&preempt_notifier_key);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(preempt_notifier_inc);
|
|
+
|
|
+void preempt_notifier_dec(void)
|
|
+{
|
|
+ static_branch_dec(&preempt_notifier_key);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(preempt_notifier_dec);
|
|
+
|
|
+/**
|
|
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
|
|
+ * @notifier: notifier struct to register
|
|
+ */
|
|
+void preempt_notifier_register(struct preempt_notifier *notifier)
|
|
+{
|
|
+ if (!static_branch_unlikely(&preempt_notifier_key))
|
|
+ WARN(1, "registering preempt_notifier while notifiers disabled\n");
|
|
+
|
|
+ hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
|
|
+
|
|
+/**
|
|
+ * preempt_notifier_unregister - no longer interested in preemption notifications
|
|
+ * @notifier: notifier struct to unregister
|
|
+ *
|
|
+ * This is *not* safe to call from within a preemption notifier.
|
|
+ */
|
|
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
|
|
+{
|
|
+ hlist_del(¬ifier->link);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
|
|
+
|
|
+static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
|
|
+{
|
|
+ struct preempt_notifier *notifier;
|
|
+
|
|
+ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
|
|
+ notifier->ops->sched_in(notifier, raw_smp_processor_id());
|
|
+}
|
|
+
|
|
+static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
|
|
+{
|
|
+ if (static_branch_unlikely(&preempt_notifier_key))
|
|
+ __fire_sched_in_preempt_notifiers(curr);
|
|
+}
|
|
+
|
|
+static void
|
|
+__fire_sched_out_preempt_notifiers(struct task_struct *curr,
|
|
+ struct task_struct *next)
|
|
+{
|
|
+ struct preempt_notifier *notifier;
|
|
+
|
|
+ hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
|
|
+ notifier->ops->sched_out(notifier, next);
|
|
+}
|
|
+
|
|
+static __always_inline void
|
|
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
|
|
+ struct task_struct *next)
|
|
+{
|
|
+ if (static_branch_unlikely(&preempt_notifier_key))
|
|
+ __fire_sched_out_preempt_notifiers(curr, next);
|
|
+}
|
|
+
|
|
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
|
|
+
|
|
+static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
|
|
+{
|
|
+}
|
|
+
|
|
+static inline void
|
|
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
|
|
+ struct task_struct *next)
|
|
+{
|
|
+}
|
|
+
|
|
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
|
|
+
|
|
+static inline void prepare_task(struct task_struct *next)
|
|
+{
|
|
+ /*
|
|
+ * Claim the task as running, we do this before switching to it
|
|
+ * such that any running task will have this set.
|
|
+ */
|
|
+ next->on_cpu = 1;
|
|
+}
|
|
+
|
|
+static inline void finish_task(struct task_struct *prev)
|
|
+{
|
|
+#ifdef CONFIG_SMP
|
|
+ /*
|
|
+ * After ->on_cpu is cleared, the task can be moved to a different CPU.
|
|
+ * We must ensure this doesn't happen until the switch is completely
|
|
+ * finished.
|
|
+ *
|
|
+ * In particular, the load of prev->state in finish_task_switch() must
|
|
+ * happen before this.
|
|
+ *
|
|
+ * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
|
|
+ */
|
|
+ smp_store_release(&prev->on_cpu, 0);
|
|
+#else
|
|
+ prev->on_cpu = 0;
|
|
+#endif
|
|
+}
|
|
+
|
|
+static inline void
|
|
+prepare_lock_switch(struct rq *rq, struct task_struct *next)
|
|
+{
|
|
+ /*
|
|
+ * Since the runqueue lock will be released by the next
|
|
+ * task (which is an invalid locking op but in the case
|
|
+ * of the scheduler it's an obvious special-case), so we
|
|
+ * do an early lockdep release here:
|
|
+ */
|
|
+ spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
|
|
+#ifdef CONFIG_DEBUG_SPINLOCK
|
|
+ /* this is a valid case when another task releases the spinlock */
|
|
+ rq->lock.owner = next;
|
|
+#endif
|
|
+}
|
|
+
|
|
+static inline void finish_lock_switch(struct rq *rq)
|
|
+{
|
|
+ /*
|
|
+ * If we are tracking spinlock dependencies then we have to
|
|
+ * fix up the runqueue lock - which gets 'carried over' from
|
|
+ * prev into current:
|
|
+ */
|
|
+ spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
|
|
+ raw_spin_unlock_irq(&rq->lock);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * prepare_task_switch - prepare to switch tasks
|
|
+ * @rq: the runqueue preparing to switch
|
|
+ * @next: the task we are going to switch to.
|
|
+ *
|
|
+ * This is called with the rq lock held and interrupts off. It must
|
|
+ * be paired with a subsequent finish_task_switch after the context
|
|
+ * switch.
|
|
+ *
|
|
+ * prepare_task_switch sets up locking and calls architecture specific
|
|
+ * hooks.
|
|
+ */
|
|
+static inline void
|
|
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
|
|
+ struct task_struct *next)
|
|
+{
|
|
+ kcov_prepare_switch(prev);
|
|
+ sched_info_switch(rq, prev, next);
|
|
+ perf_event_task_sched_out(prev, next);
|
|
+ rseq_preempt(prev);
|
|
+ fire_sched_out_preempt_notifiers(prev, next);
|
|
+ prepare_task(next);
|
|
+ prepare_arch_switch(next);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * finish_task_switch - clean up after a task-switch
|
|
+ * @rq: runqueue associated with task-switch
|
|
+ * @prev: the thread we just switched away from.
|
|
+ *
|
|
+ * finish_task_switch must be called after the context switch, paired
|
|
+ * with a prepare_task_switch call before the context switch.
|
|
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
|
|
+ * and do any other architecture-specific cleanup actions.
|
|
+ *
|
|
+ * Note that we may have delayed dropping an mm in context_switch(). If
|
|
+ * so, we finish that here outside of the runqueue lock. (Doing it
|
|
+ * with the lock held can cause deadlocks; see schedule() for
|
|
+ * details.)
|
|
+ *
|
|
+ * The context switch have flipped the stack from under us and restored the
|
|
+ * local variables which were saved when this task called schedule() in the
|
|
+ * past. prev == current is still correct but we need to recalculate this_rq
|
|
+ * because prev may have moved to another CPU.
|
|
+ */
|
|
+static struct rq *finish_task_switch(struct task_struct *prev)
|
|
+ __releases(rq->lock)
|
|
+{
|
|
+ struct rq *rq = this_rq();
|
|
+ struct mm_struct *mm = rq->prev_mm;
|
|
+ long prev_state;
|
|
+
|
|
+ /*
|
|
+ * The previous task will have left us with a preempt_count of 2
|
|
+ * because it left us after:
|
|
+ *
|
|
+ * schedule()
|
|
+ * preempt_disable(); // 1
|
|
+ * __schedule()
|
|
+ * raw_spin_lock_irq(&rq->lock) // 2
|
|
+ *
|
|
+ * Also, see FORK_PREEMPT_COUNT.
|
|
+ */
|
|
+ if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
|
|
+ "corrupted preempt_count: %s/%d/0x%x\n",
|
|
+ current->comm, current->pid, preempt_count()))
|
|
+ preempt_count_set(FORK_PREEMPT_COUNT);
|
|
+
|
|
+ rq->prev_mm = NULL;
|
|
+
|
|
+ /*
|
|
+ * A task struct has one reference for the use as "current".
|
|
+ * If a task dies, then it sets TASK_DEAD in tsk->state and calls
|
|
+ * schedule one last time. The schedule call will never return, and
|
|
+ * the scheduled task must drop that reference.
|
|
+ *
|
|
+ * We must observe prev->state before clearing prev->on_cpu (in
|
|
+ * finish_task), otherwise a concurrent wakeup can get prev
|
|
+ * running on another CPU and we could rave with its RUNNING -> DEAD
|
|
+ * transition, resulting in a double drop.
|
|
+ */
|
|
+ prev_state = prev->state;
|
|
+ vtime_task_switch(prev);
|
|
+ perf_event_task_sched_in(prev, current);
|
|
+ finish_task(prev);
|
|
+ finish_lock_switch(rq);
|
|
+ finish_arch_post_lock_switch();
|
|
+ kcov_finish_switch(current);
|
|
+
|
|
+ fire_sched_in_preempt_notifiers(current);
|
|
+ /*
|
|
+ * When switching through a kernel thread, the loop in
|
|
+ * membarrier_{private,global}_expedited() may have observed that
|
|
+ * kernel thread and not issued an IPI. It is therefore possible to
|
|
+ * schedule between user->kernel->user threads without passing though
|
|
+ * switch_mm(). Membarrier requires a barrier after storing to
|
|
+ * rq->curr, before returning to userspace, so provide them here:
|
|
+ *
|
|
+ * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
|
|
+ * provided by mmdrop(),
|
|
+ * - a sync_core for SYNC_CORE.
|
|
+ */
|
|
+ if (mm) {
|
|
+ membarrier_mm_sync_core_before_usermode(mm);
|
|
+ mmdrop(mm);
|
|
+ }
|
|
+ if (unlikely(prev_state == TASK_DEAD)) {
|
|
+ /*
|
|
+ * Remove function-return probe instances associated with this
|
|
+ * task and put them back on the free list.
|
|
+ */
|
|
+ kprobe_flush_task(prev);
|
|
+
|
|
+ /* Task is done with its stack. */
|
|
+ put_task_stack(prev);
|
|
+
|
|
+ put_task_struct_rcu_user(prev);
|
|
+ }
|
|
+
|
|
+ tick_nohz_task_switch();
|
|
+ return rq;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * schedule_tail - first thing a freshly forked thread must call.
|
|
+ * @prev: the thread we just switched away from.
|
|
+ */
|
|
+asmlinkage __visible void schedule_tail(struct task_struct *prev)
|
|
+ __releases(rq->lock)
|
|
+{
|
|
+ struct rq *rq;
|
|
+
|
|
+ /*
|
|
+ * New tasks start with FORK_PREEMPT_COUNT, see there and
|
|
+ * finish_task_switch() for details.
|
|
+ *
|
|
+ * finish_task_switch() will drop rq->lock() and lower preempt_count
|
|
+ * and the preempt_enable() will end up enabling preemption (on
|
|
+ * PREEMPT_COUNT kernels).
|
|
+ */
|
|
+
|
|
+ rq = finish_task_switch(prev);
|
|
+ preempt_enable();
|
|
+
|
|
+ if (current->set_child_tid)
|
|
+ put_user(task_pid_vnr(current), current->set_child_tid);
|
|
+
|
|
+ calculate_sigpending();
|
|
+}
|
|
+
|
|
+/*
|
|
+ * context_switch - switch to the new MM and the new thread's register state.
|
|
+ */
|
|
+static __always_inline struct rq *
|
|
+context_switch(struct rq *rq, struct task_struct *prev,
|
|
+ struct task_struct *next)
|
|
+{
|
|
+ prepare_task_switch(rq, prev, next);
|
|
+
|
|
+ /*
|
|
+ * For paravirt, this is coupled with an exit in switch_to to
|
|
+ * combine the page table reload and the switch backend into
|
|
+ * one hypercall.
|
|
+ */
|
|
+ arch_start_context_switch(prev);
|
|
+
|
|
+ /*
|
|
+ * kernel -> kernel lazy + transfer active
|
|
+ * user -> kernel lazy + mmgrab() active
|
|
+ *
|
|
+ * kernel -> user switch + mmdrop() active
|
|
+ * user -> user switch
|
|
+ */
|
|
+ if (!next->mm) { // to kernel
|
|
+ enter_lazy_tlb(prev->active_mm, next);
|
|
+
|
|
+ next->active_mm = prev->active_mm;
|
|
+ if (prev->mm) // from user
|
|
+ mmgrab(prev->active_mm);
|
|
+ else
|
|
+ prev->active_mm = NULL;
|
|
+ } else { // to user
|
|
+ membarrier_switch_mm(rq, prev->active_mm, next->mm);
|
|
+ /*
|
|
+ * sys_membarrier() requires an smp_mb() between setting
|
|
+ * rq->curr / membarrier_switch_mm() and returning to userspace.
|
|
+ *
|
|
+ * The below provides this either through switch_mm(), or in
|
|
+ * case 'prev->active_mm == next->mm' through
|
|
+ * finish_task_switch()'s mmdrop().
|
|
+ */
|
|
+ switch_mm_irqs_off(prev->active_mm, next->mm, next);
|
|
+
|
|
+ if (!prev->mm) { // from kernel
|
|
+ /* will mmdrop() in finish_task_switch(). */
|
|
+ rq->prev_mm = prev->active_mm;
|
|
+ prev->active_mm = NULL;
|
|
+ }
|
|
+ }
|
|
+
|
|
+ prepare_lock_switch(rq, next);
|
|
+
|
|
+ /* Here we just switch the register state and the stack. */
|
|
+ switch_to(prev, next, prev);
|
|
+ barrier();
|
|
+
|
|
+ return finish_task_switch(prev);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * nr_running, nr_uninterruptible and nr_context_switches:
|
|
+ *
|
|
+ * externally visible scheduler statistics: current number of runnable
|
|
+ * threads, total number of context switches performed since bootup.
|
|
+ */
|
|
+unsigned long nr_running(void)
|
|
+{
|
|
+ unsigned long i, sum = 0;
|
|
+
|
|
+ for_each_online_cpu(i)
|
|
+ sum += cpu_rq(i)->nr_running;
|
|
+
|
|
+ return sum;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Check if only the current task is running on the CPU.
|
|
+ *
|
|
+ * Caution: this function does not check that the caller has disabled
|
|
+ * preemption, thus the result might have a time-of-check-to-time-of-use
|
|
+ * race. The caller is responsible to use it correctly, for example:
|
|
+ *
|
|
+ * - from a non-preemptible section (of course)
|
|
+ *
|
|
+ * - from a thread that is bound to a single CPU
|
|
+ *
|
|
+ * - in a loop with very short iterations (e.g. a polling loop)
|
|
+ */
|
|
+bool single_task_running(void)
|
|
+{
|
|
+ return raw_rq()->nr_running == 1;
|
|
+}
|
|
+EXPORT_SYMBOL(single_task_running);
|
|
+
|
|
+unsigned long long nr_context_switches(void)
|
|
+{
|
|
+ int i;
|
|
+ unsigned long long sum = 0;
|
|
+
|
|
+ for_each_possible_cpu(i)
|
|
+ sum += cpu_rq(i)->nr_switches;
|
|
+
|
|
+ return sum;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Consumers of these two interfaces, like for example the cpuidle menu
|
|
+ * governor, are using nonsensical data. Preferring shallow idle state selection
|
|
+ * for a CPU that has IO-wait which might not even end up running the task when
|
|
+ * it does become runnable.
|
|
+ */
|
|
+
|
|
+unsigned long nr_iowait_cpu(int cpu)
|
|
+{
|
|
+ return atomic_read(&cpu_rq(cpu)->nr_iowait);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * IO-wait accounting, and how its mostly bollocks (on SMP).
|
|
+ *
|
|
+ * The idea behind IO-wait account is to account the idle time that we could
|
|
+ * have spend running if it were not for IO. That is, if we were to improve the
|
|
+ * storage performance, we'd have a proportional reduction in IO-wait time.
|
|
+ *
|
|
+ * This all works nicely on UP, where, when a task blocks on IO, we account
|
|
+ * idle time as IO-wait, because if the storage were faster, it could've been
|
|
+ * running and we'd not be idle.
|
|
+ *
|
|
+ * This has been extended to SMP, by doing the same for each CPU. This however
|
|
+ * is broken.
|
|
+ *
|
|
+ * Imagine for instance the case where two tasks block on one CPU, only the one
|
|
+ * CPU will have IO-wait accounted, while the other has regular idle. Even
|
|
+ * though, if the storage were faster, both could've ran at the same time,
|
|
+ * utilising both CPUs.
|
|
+ *
|
|
+ * This means, that when looking globally, the current IO-wait accounting on
|
|
+ * SMP is a lower bound, by reason of under accounting.
|
|
+ *
|
|
+ * Worse, since the numbers are provided per CPU, they are sometimes
|
|
+ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
|
|
+ * associated with any one particular CPU, it can wake to another CPU than it
|
|
+ * blocked on. This means the per CPU IO-wait number is meaningless.
|
|
+ *
|
|
+ * Task CPU affinities can make all that even more 'interesting'.
|
|
+ */
|
|
+
|
|
+unsigned long nr_iowait(void)
|
|
+{
|
|
+ unsigned long i, sum = 0;
|
|
+
|
|
+ for_each_possible_cpu(i)
|
|
+ sum += nr_iowait_cpu(i);
|
|
+
|
|
+ return sum;
|
|
+}
|
|
+
|
|
+DEFINE_PER_CPU(struct kernel_stat, kstat);
|
|
+DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
|
|
+
|
|
+EXPORT_PER_CPU_SYMBOL(kstat);
|
|
+EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
|
|
+
|
|
+static inline void pds_update_curr(struct rq *rq, struct task_struct *p)
|
|
+{
|
|
+ s64 ns = rq->clock_task - p->last_ran;
|
|
+
|
|
+ p->sched_time += ns;
|
|
+ account_group_exec_runtime(p, ns);
|
|
+
|
|
+ /* time_slice accounting is done in usecs to avoid overflow on 32bit */
|
|
+ p->time_slice -= NS_TO_US(ns);
|
|
+ p->last_ran = rq->clock_task;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Return accounted runtime for the task.
|
|
+ * Return separately the current's pending runtime that have not been
|
|
+ * accounted yet.
|
|
+ */
|
|
+unsigned long long task_sched_runtime(struct task_struct *p)
|
|
+{
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+ u64 ns;
|
|
+
|
|
+#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
|
|
+ /*
|
|
+ * 64-bit doesn't need locks to atomically read a 64-bit value.
|
|
+ * So we have a optimization chance when the task's delta_exec is 0.
|
|
+ * Reading ->on_cpu is racy, but this is ok.
|
|
+ *
|
|
+ * If we race with it leaving CPU, we'll take a lock. So we're correct.
|
|
+ * If we race with it entering CPU, unaccounted time is 0. This is
|
|
+ * indistinguishable from the read occurring a few cycles earlier.
|
|
+ * If we see ->on_cpu without ->on_rq, the task is leaving, and has
|
|
+ * been accounted, so we're correct here as well.
|
|
+ */
|
|
+ if (!p->on_cpu || !task_on_rq_queued(p))
|
|
+ return tsk_seruntime(p);
|
|
+#endif
|
|
+
|
|
+ rq = task_access_lock_irqsave(p, &lock, &flags);
|
|
+ /*
|
|
+ * Must be ->curr _and_ ->on_rq. If dequeued, we would
|
|
+ * project cycles that may never be accounted to this
|
|
+ * thread, breaking clock_gettime().
|
|
+ */
|
|
+ if (p == rq->curr && task_on_rq_queued(p)) {
|
|
+ update_rq_clock(rq);
|
|
+ pds_update_curr(rq, p);
|
|
+ }
|
|
+ ns = tsk_seruntime(p);
|
|
+ task_access_unlock_irqrestore(p, lock, &flags);
|
|
+
|
|
+ return ns;
|
|
+}
|
|
+
|
|
+/* This manages tasks that have run out of timeslice during a scheduler_tick */
|
|
+static inline void pds_scheduler_task_tick(struct rq *rq)
|
|
+{
|
|
+ struct task_struct *p = rq->curr;
|
|
+
|
|
+ if (is_idle_task(p))
|
|
+ return;
|
|
+
|
|
+ pds_update_curr(rq, p);
|
|
+
|
|
+ cpufreq_update_util(rq, 0);
|
|
+
|
|
+ /*
|
|
+ * Tasks that were scheduled in the first half of a tick are not
|
|
+ * allowed to run into the 2nd half of the next tick if they will
|
|
+ * run out of time slice in the interim. Otherwise, if they have
|
|
+ * less than RESCHED_US μs of time slice left they will be rescheduled.
|
|
+ */
|
|
+ if (p->time_slice - rq->dither >= RESCHED_US)
|
|
+ return;
|
|
+
|
|
+ /**
|
|
+ * p->time_slice < RESCHED_US. We will modify task_struct under
|
|
+ * rq lock as p is rq->curr
|
|
+ */
|
|
+ __set_tsk_resched(p);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+static int active_load_balance_cpu_stop(void *data)
|
|
+{
|
|
+ struct rq *rq = this_rq();
|
|
+ struct task_struct *p = data;
|
|
+ int cpu;
|
|
+ unsigned long flags;
|
|
+
|
|
+ local_irq_save(flags);
|
|
+
|
|
+ raw_spin_lock(&p->pi_lock);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+
|
|
+ rq->active_balance = 0;
|
|
+ /*
|
|
+ * _something_ may have changed the task, double check again
|
|
+ */
|
|
+ if (task_on_rq_queued(p) && task_rq(p) == rq &&
|
|
+ (cpu = cpumask_any_and(&p->cpus_mask, &sched_cpu_sg_idle_mask)) < nr_cpu_ids)
|
|
+ rq = __migrate_task(rq, p, cpu);
|
|
+
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock(&p->pi_lock);
|
|
+
|
|
+ local_irq_restore(flags);
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+/* pds_sg_balance_trigger - trigger slibing group balance for @cpu */
|
|
+static void pds_sg_balance_trigger(const int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+ struct task_struct *curr;
|
|
+
|
|
+ if (!raw_spin_trylock_irqsave(&rq->lock, flags))
|
|
+ return;
|
|
+ curr = rq->curr;
|
|
+ if (!is_idle_task(curr) &&
|
|
+ cpumask_intersects(&curr->cpus_mask, &sched_cpu_sg_idle_mask)) {
|
|
+ int active_balance = 0;
|
|
+
|
|
+ if (likely(!rq->active_balance)) {
|
|
+ rq->active_balance = 1;
|
|
+ active_balance = 1;
|
|
+ }
|
|
+
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+
|
|
+ if (likely(active_balance))
|
|
+ stop_one_cpu_nowait(cpu, active_load_balance_cpu_stop,
|
|
+ curr, &rq->active_balance_work);
|
|
+ } else
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * pds_sg_balance_check - slibing group balance check for run queue @rq
|
|
+ */
|
|
+static inline void pds_sg_balance_check(const struct rq *rq)
|
|
+{
|
|
+ cpumask_t chk;
|
|
+ int i;
|
|
+
|
|
+ /* Only online cpu will do sg balance checking */
|
|
+ if (unlikely(!rq->online))
|
|
+ return;
|
|
+
|
|
+ /* Only cpu in slibing idle group will do the checking */
|
|
+ if (!cpumask_test_cpu(cpu_of(rq), &sched_cpu_sg_idle_mask))
|
|
+ return;
|
|
+
|
|
+ /* Find potential cpus which can migrate the currently running task */
|
|
+ if (!cpumask_andnot(&chk, &sched_rq_pending_masks[SCHED_RQ_EMPTY],
|
|
+ &sched_rq_queued_masks[SCHED_RQ_EMPTY]))
|
|
+ return;
|
|
+
|
|
+ for_each_cpu(i, &chk) {
|
|
+ /* skip the cpu which has idle slibing cpu */
|
|
+ if (cpumask_test_cpu(per_cpu(sched_sibling_cpu, i),
|
|
+ &sched_rq_queued_masks[SCHED_RQ_EMPTY]))
|
|
+ continue;
|
|
+ pds_sg_balance_trigger(i);
|
|
+ }
|
|
+}
|
|
+#endif /* CONFIG_SCHED_SMT */
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+/*
|
|
+ * This function gets called by the timer code, with HZ frequency.
|
|
+ * We call it with interrupts disabled.
|
|
+ */
|
|
+void scheduler_tick(void)
|
|
+{
|
|
+ int cpu __maybe_unused = smp_processor_id();
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+
|
|
+ sched_clock_tick();
|
|
+
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ update_rq_clock(rq);
|
|
+
|
|
+ pds_scheduler_task_tick(rq);
|
|
+ update_sched_rq_queued_masks_normal(rq);
|
|
+ calc_global_load_tick(rq);
|
|
+ psi_task_tick(rq);
|
|
+
|
|
+ rq->last_tick = rq->clock;
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+
|
|
+ perf_event_task_tick();
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_NO_HZ_FULL
|
|
+struct tick_work {
|
|
+ int cpu;
|
|
+ atomic_t state;
|
|
+ struct delayed_work work;
|
|
+};
|
|
+/* Values for ->state, see diagram below. */
|
|
+#define TICK_SCHED_REMOTE_OFFLINE 0
|
|
+#define TICK_SCHED_REMOTE_OFFLINING 1
|
|
+#define TICK_SCHED_REMOTE_RUNNING 2
|
|
+
|
|
+/*
|
|
+ * State diagram for ->state:
|
|
+ *
|
|
+ *
|
|
+ * TICK_SCHED_REMOTE_OFFLINE
|
|
+ * | ^
|
|
+ * | |
|
|
+ * | | sched_tick_remote()
|
|
+ * | |
|
|
+ * | |
|
|
+ * +--TICK_SCHED_REMOTE_OFFLINING
|
|
+ * | ^
|
|
+ * | |
|
|
+ * sched_tick_start() | | sched_tick_stop()
|
|
+ * | |
|
|
+ * V |
|
|
+ * TICK_SCHED_REMOTE_RUNNING
|
|
+ *
|
|
+ *
|
|
+ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
|
|
+ * and sched_tick_start() are happy to leave the state in RUNNING.
|
|
+ */
|
|
+
|
|
+static struct tick_work __percpu *tick_work_cpu;
|
|
+
|
|
+static void sched_tick_remote(struct work_struct *work)
|
|
+{
|
|
+ struct delayed_work *dwork = to_delayed_work(work);
|
|
+ struct tick_work *twork = container_of(dwork, struct tick_work, work);
|
|
+ int cpu = twork->cpu;
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ struct task_struct *curr;
|
|
+ unsigned long flags;
|
|
+ u64 delta;
|
|
+ int os;
|
|
+
|
|
+ /*
|
|
+ * Handle the tick only if it appears the remote CPU is running in full
|
|
+ * dynticks mode. The check is racy by nature, but missing a tick or
|
|
+ * having one too much is no big deal because the scheduler tick updates
|
|
+ * statistics and checks timeslices in a time-independent way, regardless
|
|
+ * of when exactly it is running.
|
|
+ */
|
|
+ if (idle_cpu(cpu) || !tick_nohz_tick_stopped_cpu(cpu))
|
|
+ goto out_requeue;
|
|
+
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ curr = rq->curr;
|
|
+
|
|
+ if (is_idle_task(curr) || cpu_is_offline(cpu))
|
|
+ goto out_unlock;
|
|
+
|
|
+ update_rq_clock(rq);
|
|
+ delta = rq_clock_task(rq) - curr->last_ran;
|
|
+
|
|
+ /*
|
|
+ * Make sure the next tick runs within a reasonable
|
|
+ * amount of time.
|
|
+ */
|
|
+ WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
|
|
+ pds_scheduler_task_tick(rq);
|
|
+ update_sched_rq_queued_masks_normal(rq);
|
|
+
|
|
+out_unlock:
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+
|
|
+out_requeue:
|
|
+ /*
|
|
+ * Run the remote tick once per second (1Hz). This arbitrary
|
|
+ * frequency is large enough to avoid overload but short enough
|
|
+ * to keep scheduler internal stats reasonably up to date. But
|
|
+ * first update state to reflect hotplug activity if required.
|
|
+ */
|
|
+ os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
|
|
+ WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
|
|
+ if (os == TICK_SCHED_REMOTE_RUNNING)
|
|
+ queue_delayed_work(system_unbound_wq, dwork, HZ);
|
|
+}
|
|
+
|
|
+static void sched_tick_start(int cpu)
|
|
+{
|
|
+ int os;
|
|
+ struct tick_work *twork;
|
|
+
|
|
+ if (housekeeping_cpu(cpu, HK_FLAG_TICK))
|
|
+ return;
|
|
+
|
|
+ WARN_ON_ONCE(!tick_work_cpu);
|
|
+
|
|
+ twork = per_cpu_ptr(tick_work_cpu, cpu);
|
|
+ os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
|
|
+ WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
|
|
+ if (os == TICK_SCHED_REMOTE_OFFLINE) {
|
|
+ twork->cpu = cpu;
|
|
+ INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
|
|
+ queue_delayed_work(system_unbound_wq, &twork->work, HZ);
|
|
+ }
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_HOTPLUG_CPU
|
|
+static void sched_tick_stop(int cpu)
|
|
+{
|
|
+ struct tick_work *twork;
|
|
+
|
|
+ if (housekeeping_cpu(cpu, HK_FLAG_TICK))
|
|
+ return;
|
|
+
|
|
+ WARN_ON_ONCE(!tick_work_cpu);
|
|
+
|
|
+ twork = per_cpu_ptr(tick_work_cpu, cpu);
|
|
+ cancel_delayed_work_sync(&twork->work);
|
|
+}
|
|
+#endif /* CONFIG_HOTPLUG_CPU */
|
|
+
|
|
+int __init sched_tick_offload_init(void)
|
|
+{
|
|
+ tick_work_cpu = alloc_percpu(struct tick_work);
|
|
+ BUG_ON(!tick_work_cpu);
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+#else /* !CONFIG_NO_HZ_FULL */
|
|
+static inline void sched_tick_start(int cpu) { }
|
|
+static inline void sched_tick_stop(int cpu) { }
|
|
+#endif
|
|
+
|
|
+#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
|
|
+ defined(CONFIG_PREEMPT_TRACER))
|
|
+/*
|
|
+ * If the value passed in is equal to the current preempt count
|
|
+ * then we just disabled preemption. Start timing the latency.
|
|
+ */
|
|
+static inline void preempt_latency_start(int val)
|
|
+{
|
|
+ if (preempt_count() == val) {
|
|
+ unsigned long ip = get_lock_parent_ip();
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ current->preempt_disable_ip = ip;
|
|
+#endif
|
|
+ trace_preempt_off(CALLER_ADDR0, ip);
|
|
+ }
|
|
+}
|
|
+
|
|
+void preempt_count_add(int val)
|
|
+{
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ /*
|
|
+ * Underflow?
|
|
+ */
|
|
+ if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
|
|
+ return;
|
|
+#endif
|
|
+ __preempt_count_add(val);
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ /*
|
|
+ * Spinlock count overflowing soon?
|
|
+ */
|
|
+ DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
|
|
+ PREEMPT_MASK - 10);
|
|
+#endif
|
|
+ preempt_latency_start(val);
|
|
+}
|
|
+EXPORT_SYMBOL(preempt_count_add);
|
|
+NOKPROBE_SYMBOL(preempt_count_add);
|
|
+
|
|
+/*
|
|
+ * If the value passed in equals to the current preempt count
|
|
+ * then we just enabled preemption. Stop timing the latency.
|
|
+ */
|
|
+static inline void preempt_latency_stop(int val)
|
|
+{
|
|
+ if (preempt_count() == val)
|
|
+ trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
|
|
+}
|
|
+
|
|
+void preempt_count_sub(int val)
|
|
+{
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ /*
|
|
+ * Underflow?
|
|
+ */
|
|
+ if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
|
|
+ return;
|
|
+ /*
|
|
+ * Is the spinlock portion underflowing?
|
|
+ */
|
|
+ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
|
|
+ !(preempt_count() & PREEMPT_MASK)))
|
|
+ return;
|
|
+#endif
|
|
+
|
|
+ preempt_latency_stop(val);
|
|
+ __preempt_count_sub(val);
|
|
+}
|
|
+EXPORT_SYMBOL(preempt_count_sub);
|
|
+NOKPROBE_SYMBOL(preempt_count_sub);
|
|
+
|
|
+#else
|
|
+static inline void preempt_latency_start(int val) { }
|
|
+static inline void preempt_latency_stop(int val) { }
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * Timeslices below RESCHED_US are considered as good as expired as there's no
|
|
+ * point rescheduling when there's so little time left. SCHED_BATCH tasks
|
|
+ * have been flagged be not latency sensitive and likely to be fully CPU
|
|
+ * bound so every time they're rescheduled they have their time_slice
|
|
+ * refilled, but get a new later deadline to have little effect on
|
|
+ * SCHED_NORMAL tasks.
|
|
+
|
|
+ */
|
|
+static inline void check_deadline(struct task_struct *p, struct rq *rq)
|
|
+{
|
|
+ if (rq->idle == p)
|
|
+ return;
|
|
+
|
|
+ pds_update_curr(rq, p);
|
|
+
|
|
+ if (p->time_slice < RESCHED_US) {
|
|
+ time_slice_expired(p, rq);
|
|
+ if (SCHED_ISO == p->policy && ISO_PRIO == p->prio) {
|
|
+ p->prio = NORMAL_PRIO;
|
|
+ p->deadline = rq->clock + task_deadline_diff(p);
|
|
+ update_task_priodl(p);
|
|
+ }
|
|
+ if (SCHED_FIFO != p->policy && task_on_rq_queued(p))
|
|
+ requeue_task(p, rq);
|
|
+ }
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+
|
|
+#define SCHED_RQ_NR_MIGRATION (32UL)
|
|
+/*
|
|
+ * Migrate pending tasks in @rq to @dest_cpu
|
|
+ * Will try to migrate mininal of half of @rq nr_running tasks and
|
|
+ * SCHED_RQ_NR_MIGRATION to @dest_cpu
|
|
+ */
|
|
+static inline int
|
|
+migrate_pending_tasks(struct rq *rq, struct rq *dest_rq, int filter_prio)
|
|
+{
|
|
+ struct task_struct *p;
|
|
+ int dest_cpu = cpu_of(dest_rq);
|
|
+ int nr_migrated = 0;
|
|
+ int nr_tries = min((rq->nr_running + 1) / 2, SCHED_RQ_NR_MIGRATION);
|
|
+ struct skiplist_node *node = rq->sl_header.next[0];
|
|
+
|
|
+ while (nr_tries && node != &rq->sl_header) {
|
|
+ p = skiplist_entry(node, struct task_struct, sl_node);
|
|
+ node = node->next[0];
|
|
+
|
|
+ if (task_running(p))
|
|
+ continue;
|
|
+ if (p->prio >= filter_prio)
|
|
+ break;
|
|
+ if (cpumask_test_cpu(dest_cpu, &p->cpus_mask)) {
|
|
+ detach_task(rq, p, dest_cpu);
|
|
+ attach_task(dest_rq, p);
|
|
+ nr_migrated++;
|
|
+ }
|
|
+ nr_tries--;
|
|
+ /* make a jump */
|
|
+ if (node == &rq->sl_header)
|
|
+ break;
|
|
+ node = node->next[0];
|
|
+ }
|
|
+
|
|
+ return nr_migrated;
|
|
+}
|
|
+
|
|
+static inline int
|
|
+take_queued_task_cpumask(struct rq *rq, cpumask_t *chk_mask, int filter_prio)
|
|
+{
|
|
+ int src_cpu;
|
|
+
|
|
+ for_each_cpu(src_cpu, chk_mask) {
|
|
+ int nr_migrated;
|
|
+ struct rq *src_rq = cpu_rq(src_cpu);
|
|
+
|
|
+ if (!do_raw_spin_trylock(&src_rq->lock)) {
|
|
+ if (PRIO_LIMIT == filter_prio)
|
|
+ continue;
|
|
+ return 0;
|
|
+ }
|
|
+ spin_acquire(&src_rq->lock.dep_map, SINGLE_DEPTH_NESTING, 1, _RET_IP_);
|
|
+
|
|
+ update_rq_clock(src_rq);
|
|
+ nr_migrated = migrate_pending_tasks(src_rq, rq, filter_prio);
|
|
+
|
|
+ spin_release(&src_rq->lock.dep_map, 1, _RET_IP_);
|
|
+ do_raw_spin_unlock(&src_rq->lock);
|
|
+
|
|
+ if (nr_migrated || PRIO_LIMIT != filter_prio)
|
|
+ return nr_migrated;
|
|
+ }
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static inline int take_other_rq_task(struct rq *rq, int cpu, int filter_prio)
|
|
+{
|
|
+ struct cpumask *affinity_mask, *end;
|
|
+ struct cpumask chk;
|
|
+
|
|
+ if (PRIO_LIMIT == filter_prio) {
|
|
+ cpumask_complement(&chk, &sched_rq_pending_masks[SCHED_RQ_EMPTY]);
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+ {
|
|
+ /* also try to take IDLE priority tasks from smt supressed cpu */
|
|
+ struct cpumask t;
|
|
+ if (cpumask_and(&t, &sched_smt_supressed_mask,
|
|
+ &sched_rq_queued_masks[SCHED_RQ_IDLE]))
|
|
+ cpumask_or(&chk, &chk, &t);
|
|
+ }
|
|
+#endif
|
|
+ } else if (NORMAL_PRIO == filter_prio) {
|
|
+ cpumask_or(&chk, &sched_rq_pending_masks[SCHED_RQ_RT],
|
|
+ &sched_rq_pending_masks[SCHED_RQ_ISO]);
|
|
+ } else if (IDLE_PRIO == filter_prio) {
|
|
+ cpumask_complement(&chk, &sched_rq_pending_masks[SCHED_RQ_EMPTY]);
|
|
+ cpumask_andnot(&chk, &chk, &sched_rq_pending_masks[SCHED_RQ_IDLE]);
|
|
+ } else
|
|
+ cpumask_copy(&chk, &sched_rq_pending_masks[SCHED_RQ_RT]);
|
|
+
|
|
+ if (cpumask_empty(&chk))
|
|
+ return 0;
|
|
+
|
|
+ affinity_mask = per_cpu(sched_cpu_llc_start_mask, cpu);
|
|
+ end = per_cpu(sched_cpu_affinity_chk_end_masks, cpu);
|
|
+ do {
|
|
+ struct cpumask tmp;
|
|
+
|
|
+ if (cpumask_and(&tmp, &chk, affinity_mask) &&
|
|
+ take_queued_task_cpumask(rq, &tmp, filter_prio))
|
|
+ return 1;
|
|
+ } while (++affinity_mask < end);
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+#endif
|
|
+
|
|
+static inline struct task_struct *
|
|
+choose_next_task(struct rq *rq, int cpu, struct task_struct *prev)
|
|
+{
|
|
+ struct task_struct *next = rq_first_queued_task(rq);
|
|
+
|
|
+#ifdef CONFIG_SMT_NICE
|
|
+ if (cpumask_test_cpu(cpu, &sched_smt_supressed_mask)) {
|
|
+ if (next->prio >= IDLE_PRIO) {
|
|
+ if (rq->online &&
|
|
+ take_other_rq_task(rq, cpu, IDLE_PRIO))
|
|
+ return rq_first_queued_task(rq);
|
|
+ return rq->idle;
|
|
+ }
|
|
+ }
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ if (likely(rq->online))
|
|
+ if (take_other_rq_task(rq, cpu, next->prio)) {
|
|
+ resched_curr(rq);
|
|
+ return rq_first_queued_task(rq);
|
|
+ }
|
|
+#endif
|
|
+ return next;
|
|
+}
|
|
+
|
|
+static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
|
|
+{
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ return p->preempt_disable_ip;
|
|
+#else
|
|
+ return 0;
|
|
+#endif
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Print scheduling while atomic bug:
|
|
+ */
|
|
+static noinline void __schedule_bug(struct task_struct *prev)
|
|
+{
|
|
+ /* Save this before calling printk(), since that will clobber it */
|
|
+ unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
|
|
+
|
|
+ if (oops_in_progress)
|
|
+ return;
|
|
+
|
|
+ printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
|
|
+ prev->comm, prev->pid, preempt_count());
|
|
+
|
|
+ debug_show_held_locks(prev);
|
|
+ print_modules();
|
|
+ if (irqs_disabled())
|
|
+ print_irqtrace_events(prev);
|
|
+ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
|
|
+ && in_atomic_preempt_off()) {
|
|
+ pr_err("Preemption disabled at:");
|
|
+ print_ip_sym(preempt_disable_ip);
|
|
+ pr_cont("\n");
|
|
+ }
|
|
+ if (panic_on_warn)
|
|
+ panic("scheduling while atomic\n");
|
|
+
|
|
+ dump_stack();
|
|
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Various schedule()-time debugging checks and statistics:
|
|
+ */
|
|
+static inline void schedule_debug(struct task_struct *prev, bool preempt)
|
|
+{
|
|
+#ifdef CONFIG_SCHED_STACK_END_CHECK
|
|
+ if (task_stack_end_corrupted(prev))
|
|
+ panic("corrupted stack end detected inside scheduler\n");
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
|
|
+ if (!preempt && prev->state && prev->non_block_count) {
|
|
+ printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
|
|
+ prev->comm, prev->pid, prev->non_block_count);
|
|
+ dump_stack();
|
|
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
|
|
+ }
|
|
+#endif
|
|
+
|
|
+ if (unlikely(in_atomic_preempt_off())) {
|
|
+ __schedule_bug(prev);
|
|
+ preempt_count_set(PREEMPT_DISABLED);
|
|
+ }
|
|
+ rcu_sleep_check();
|
|
+
|
|
+ profile_hit(SCHED_PROFILING, __builtin_return_address(0));
|
|
+
|
|
+ schedstat_inc(this_rq()->sched_count);
|
|
+}
|
|
+
|
|
+static inline void set_rq_task(struct rq *rq, struct task_struct *p)
|
|
+{
|
|
+ p->last_ran = rq->clock_task;
|
|
+
|
|
+#ifdef CONFIG_HIGH_RES_TIMERS
|
|
+ if (p != rq->idle)
|
|
+ hrtick_start(rq, US_TO_NS(p->time_slice));
|
|
+#endif
|
|
+ /* update rq->dither */
|
|
+ rq->dither = rq_dither(rq);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * schedule() is the main scheduler function.
|
|
+ *
|
|
+ * The main means of driving the scheduler and thus entering this function are:
|
|
+ *
|
|
+ * 1. Explicit blocking: mutex, semaphore, waitqueue, etc.
|
|
+ *
|
|
+ * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
|
|
+ * paths. For example, see arch/x86/entry_64.S.
|
|
+ *
|
|
+ * To drive preemption between tasks, the scheduler sets the flag in timer
|
|
+ * interrupt handler scheduler_tick().
|
|
+ *
|
|
+ * 3. Wakeups don't really cause entry into schedule(). They add a
|
|
+ * task to the run-queue and that's it.
|
|
+ *
|
|
+ * Now, if the new task added to the run-queue preempts the current
|
|
+ * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
|
|
+ * called on the nearest possible occasion:
|
|
+ *
|
|
+ * - If the kernel is preemptible (CONFIG_PREEMPTION=y):
|
|
+ *
|
|
+ * - in syscall or exception context, at the next outmost
|
|
+ * preempt_enable(). (this might be as soon as the wake_up()'s
|
|
+ * spin_unlock()!)
|
|
+ *
|
|
+ * - in IRQ context, return from interrupt-handler to
|
|
+ * preemptible context
|
|
+ *
|
|
+ * - If the kernel is not preemptible (CONFIG_PREEMPT is not set)
|
|
+ * then at the next:
|
|
+ *
|
|
+ * - cond_resched() call
|
|
+ * - explicit schedule() call
|
|
+ * - return from syscall or exception to user-space
|
|
+ * - return from interrupt-handler to user-space
|
|
+ *
|
|
+ * WARNING: must be called with preemption disabled!
|
|
+ */
|
|
+static void __sched notrace __schedule(bool preempt)
|
|
+{
|
|
+ struct task_struct *prev, *next;
|
|
+ unsigned long *switch_count;
|
|
+ struct rq *rq;
|
|
+ int cpu;
|
|
+
|
|
+ cpu = smp_processor_id();
|
|
+ rq = cpu_rq(cpu);
|
|
+ prev = rq->curr;
|
|
+
|
|
+ schedule_debug(prev, preempt);
|
|
+
|
|
+ /* by passing sched_feat(HRTICK) checking which PDS doesn't support */
|
|
+ hrtick_clear(rq);
|
|
+
|
|
+ local_irq_disable();
|
|
+ rcu_note_context_switch(preempt);
|
|
+
|
|
+ /*
|
|
+ * Make sure that signal_pending_state()->signal_pending() below
|
|
+ * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
|
|
+ * done by the caller to avoid the race with signal_wake_up().
|
|
+ *
|
|
+ * The membarrier system call requires a full memory barrier
|
|
+ * after coming from user-space, before storing to rq->curr.
|
|
+ */
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ smp_mb__after_spinlock();
|
|
+
|
|
+ update_rq_clock(rq);
|
|
+
|
|
+ switch_count = &prev->nivcsw;
|
|
+ if (!preempt && prev->state) {
|
|
+ if (signal_pending_state(prev->state, prev)) {
|
|
+ prev->state = TASK_RUNNING;
|
|
+ } else {
|
|
+ deactivate_task(prev, rq);
|
|
+
|
|
+ if (prev->in_iowait) {
|
|
+ atomic_inc(&rq->nr_iowait);
|
|
+ delayacct_blkio_start();
|
|
+ }
|
|
+ }
|
|
+ switch_count = &prev->nvcsw;
|
|
+ }
|
|
+
|
|
+ clear_tsk_need_resched(prev);
|
|
+ clear_preempt_need_resched();
|
|
+
|
|
+ check_deadline(prev, rq);
|
|
+
|
|
+ next = choose_next_task(rq, cpu, prev);
|
|
+
|
|
+ set_rq_task(rq, next);
|
|
+
|
|
+ if (prev != next) {
|
|
+ if (next->prio == PRIO_LIMIT)
|
|
+ schedstat_inc(rq->sched_goidle);
|
|
+
|
|
+ /*
|
|
+ * RCU users of rcu_dereference(rq->curr) may not see
|
|
+ * changes to task_struct made by pick_next_task().
|
|
+ */
|
|
+ RCU_INIT_POINTER(rq->curr, next);
|
|
+ /*
|
|
+ * The membarrier system call requires each architecture
|
|
+ * to have a full memory barrier after updating
|
|
+ * rq->curr, before returning to user-space.
|
|
+ *
|
|
+ * Here are the schemes providing that barrier on the
|
|
+ * various architectures:
|
|
+ * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
|
|
+ * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
|
|
+ * - finish_lock_switch() for weakly-ordered
|
|
+ * architectures where spin_unlock is a full barrier,
|
|
+ * - switch_to() for arm64 (weakly-ordered, spin_unlock
|
|
+ * is a RELEASE barrier),
|
|
+ */
|
|
+ ++*switch_count;
|
|
+ rq->nr_switches++;
|
|
+
|
|
+ trace_sched_switch(preempt, prev, next);
|
|
+
|
|
+ /* Also unlocks the rq: */
|
|
+ rq = context_switch(rq, prev, next);
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ pds_sg_balance_check(rq);
|
|
+#endif
|
|
+ } else
|
|
+ raw_spin_unlock_irq(&rq->lock);
|
|
+}
|
|
+
|
|
+void __noreturn do_task_dead(void)
|
|
+{
|
|
+ /* Causes final put_task_struct in finish_task_switch(): */
|
|
+ set_special_state(TASK_DEAD);
|
|
+
|
|
+ /* Tell freezer to ignore us: */
|
|
+ current->flags |= PF_NOFREEZE;
|
|
+ __schedule(false);
|
|
+
|
|
+ BUG();
|
|
+
|
|
+ /* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
|
|
+ for (;;)
|
|
+ cpu_relax();
|
|
+}
|
|
+
|
|
+static inline void sched_submit_work(struct task_struct *tsk)
|
|
+{
|
|
+ if (!tsk->state || tsk_is_pi_blocked(tsk) ||
|
|
+ signal_pending_state(tsk->state, tsk))
|
|
+ return;
|
|
+
|
|
+ /*
|
|
+ * If a worker went to sleep, notify and ask workqueue whether
|
|
+ * it wants to wake up a task to maintain concurrency.
|
|
+ * As this function is called inside the schedule() context,
|
|
+ * we disable preemption to avoid it calling schedule() again
|
|
+ * in the possible wakeup of a kworker.
|
|
+ */
|
|
+ if (tsk->flags & PF_WQ_WORKER) {
|
|
+ preempt_disable();
|
|
+ wq_worker_sleeping(tsk);
|
|
+ preempt_enable_no_resched();
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * If we are going to sleep and we have plugged IO queued,
|
|
+ * make sure to submit it to avoid deadlocks.
|
|
+ */
|
|
+ if (blk_needs_flush_plug(tsk))
|
|
+ blk_schedule_flush_plug(tsk);
|
|
+}
|
|
+
|
|
+static void sched_update_worker(struct task_struct *tsk)
|
|
+{
|
|
+ if (tsk->flags & PF_WQ_WORKER)
|
|
+ wq_worker_running(tsk);
|
|
+}
|
|
+
|
|
+asmlinkage __visible void __sched schedule(void)
|
|
+{
|
|
+ struct task_struct *tsk = current;
|
|
+
|
|
+ sched_submit_work(tsk);
|
|
+ do {
|
|
+ preempt_disable();
|
|
+ __schedule(false);
|
|
+ sched_preempt_enable_no_resched();
|
|
+ } while (need_resched());
|
|
+ sched_update_worker(tsk);
|
|
+}
|
|
+EXPORT_SYMBOL(schedule);
|
|
+
|
|
+/*
|
|
+ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
|
|
+ * state (have scheduled out non-voluntarily) by making sure that all
|
|
+ * tasks have either left the run queue or have gone into user space.
|
|
+ * As idle tasks do not do either, they must not ever be preempted
|
|
+ * (schedule out non-voluntarily).
|
|
+ *
|
|
+ * schedule_idle() is similar to schedule_preempt_disable() except that it
|
|
+ * never enables preemption because it does not call sched_submit_work().
|
|
+ */
|
|
+void __sched schedule_idle(void)
|
|
+{
|
|
+ /*
|
|
+ * As this skips calling sched_submit_work(), which the idle task does
|
|
+ * regardless because that function is a nop when the task is in a
|
|
+ * TASK_RUNNING state, make sure this isn't used someplace that the
|
|
+ * current task can be in any other state. Note, idle is always in the
|
|
+ * TASK_RUNNING state.
|
|
+ */
|
|
+ WARN_ON_ONCE(current->state);
|
|
+ do {
|
|
+ __schedule(false);
|
|
+ } while (need_resched());
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_CONTEXT_TRACKING
|
|
+asmlinkage __visible void __sched schedule_user(void)
|
|
+{
|
|
+ /*
|
|
+ * If we come here after a random call to set_need_resched(),
|
|
+ * or we have been woken up remotely but the IPI has not yet arrived,
|
|
+ * we haven't yet exited the RCU idle mode. Do it here manually until
|
|
+ * we find a better solution.
|
|
+ *
|
|
+ * NB: There are buggy callers of this function. Ideally we
|
|
+ * should warn if prev_state != CONTEXT_USER, but that will trigger
|
|
+ * too frequently to make sense yet.
|
|
+ */
|
|
+ enum ctx_state prev_state = exception_enter();
|
|
+ schedule();
|
|
+ exception_exit(prev_state);
|
|
+}
|
|
+#endif
|
|
+
|
|
+/**
|
|
+ * schedule_preempt_disabled - called with preemption disabled
|
|
+ *
|
|
+ * Returns with preemption disabled. Note: preempt_count must be 1
|
|
+ */
|
|
+void __sched schedule_preempt_disabled(void)
|
|
+{
|
|
+ sched_preempt_enable_no_resched();
|
|
+ schedule();
|
|
+ preempt_disable();
|
|
+}
|
|
+
|
|
+static void __sched notrace preempt_schedule_common(void)
|
|
+{
|
|
+ do {
|
|
+ /*
|
|
+ * Because the function tracer can trace preempt_count_sub()
|
|
+ * and it also uses preempt_enable/disable_notrace(), if
|
|
+ * NEED_RESCHED is set, the preempt_enable_notrace() called
|
|
+ * by the function tracer will call this function again and
|
|
+ * cause infinite recursion.
|
|
+ *
|
|
+ * Preemption must be disabled here before the function
|
|
+ * tracer can trace. Break up preempt_disable() into two
|
|
+ * calls. One to disable preemption without fear of being
|
|
+ * traced. The other to still record the preemption latency,
|
|
+ * which can also be traced by the function tracer.
|
|
+ */
|
|
+ preempt_disable_notrace();
|
|
+ preempt_latency_start(1);
|
|
+ __schedule(true);
|
|
+ preempt_latency_stop(1);
|
|
+ preempt_enable_no_resched_notrace();
|
|
+
|
|
+ /*
|
|
+ * Check again in case we missed a preemption opportunity
|
|
+ * between schedule and now.
|
|
+ */
|
|
+ } while (need_resched());
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_PREEMPTION
|
|
+/*
|
|
+ * This is the entry point to schedule() from in-kernel preemption
|
|
+ * off of preempt_enable.
|
|
+ */
|
|
+asmlinkage __visible void __sched notrace preempt_schedule(void)
|
|
+{
|
|
+ /*
|
|
+ * If there is a non-zero preempt_count or interrupts are disabled,
|
|
+ * we do not want to preempt the current task. Just return..
|
|
+ */
|
|
+ if (likely(!preemptible()))
|
|
+ return;
|
|
+
|
|
+ preempt_schedule_common();
|
|
+}
|
|
+NOKPROBE_SYMBOL(preempt_schedule);
|
|
+EXPORT_SYMBOL(preempt_schedule);
|
|
+
|
|
+/**
|
|
+ * preempt_schedule_notrace - preempt_schedule called by tracing
|
|
+ *
|
|
+ * The tracing infrastructure uses preempt_enable_notrace to prevent
|
|
+ * recursion and tracing preempt enabling caused by the tracing
|
|
+ * infrastructure itself. But as tracing can happen in areas coming
|
|
+ * from userspace or just about to enter userspace, a preempt enable
|
|
+ * can occur before user_exit() is called. This will cause the scheduler
|
|
+ * to be called when the system is still in usermode.
|
|
+ *
|
|
+ * To prevent this, the preempt_enable_notrace will use this function
|
|
+ * instead of preempt_schedule() to exit user context if needed before
|
|
+ * calling the scheduler.
|
|
+ */
|
|
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
|
|
+{
|
|
+ enum ctx_state prev_ctx;
|
|
+
|
|
+ if (likely(!preemptible()))
|
|
+ return;
|
|
+
|
|
+ do {
|
|
+ /*
|
|
+ * Because the function tracer can trace preempt_count_sub()
|
|
+ * and it also uses preempt_enable/disable_notrace(), if
|
|
+ * NEED_RESCHED is set, the preempt_enable_notrace() called
|
|
+ * by the function tracer will call this function again and
|
|
+ * cause infinite recursion.
|
|
+ *
|
|
+ * Preemption must be disabled here before the function
|
|
+ * tracer can trace. Break up preempt_disable() into two
|
|
+ * calls. One to disable preemption without fear of being
|
|
+ * traced. The other to still record the preemption latency,
|
|
+ * which can also be traced by the function tracer.
|
|
+ */
|
|
+ preempt_disable_notrace();
|
|
+ preempt_latency_start(1);
|
|
+ /*
|
|
+ * Needs preempt disabled in case user_exit() is traced
|
|
+ * and the tracer calls preempt_enable_notrace() causing
|
|
+ * an infinite recursion.
|
|
+ */
|
|
+ prev_ctx = exception_enter();
|
|
+ __schedule(true);
|
|
+ exception_exit(prev_ctx);
|
|
+
|
|
+ preempt_latency_stop(1);
|
|
+ preempt_enable_no_resched_notrace();
|
|
+ } while (need_resched());
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
|
|
+
|
|
+#endif /* CONFIG_PREEMPTION */
|
|
+
|
|
+/*
|
|
+ * This is the entry point to schedule() from kernel preemption
|
|
+ * off of irq context.
|
|
+ * Note, that this is called and return with irqs disabled. This will
|
|
+ * protect us against recursive calling from irq.
|
|
+ */
|
|
+asmlinkage __visible void __sched preempt_schedule_irq(void)
|
|
+{
|
|
+ enum ctx_state prev_state;
|
|
+
|
|
+ /* Catch callers which need to be fixed */
|
|
+ BUG_ON(preempt_count() || !irqs_disabled());
|
|
+
|
|
+ prev_state = exception_enter();
|
|
+
|
|
+ do {
|
|
+ preempt_disable();
|
|
+ local_irq_enable();
|
|
+ __schedule(true);
|
|
+ local_irq_disable();
|
|
+ sched_preempt_enable_no_resched();
|
|
+ } while (need_resched());
|
|
+
|
|
+ exception_exit(prev_state);
|
|
+}
|
|
+
|
|
+int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
|
|
+ void *key)
|
|
+{
|
|
+ return try_to_wake_up(curr->private, mode, wake_flags);
|
|
+}
|
|
+EXPORT_SYMBOL(default_wake_function);
|
|
+
|
|
+static inline void
|
|
+check_task_changed(struct rq *rq, struct task_struct *p)
|
|
+{
|
|
+ /*
|
|
+ * Trigger changes when task priority/deadline modified.
|
|
+ */
|
|
+ if (task_on_rq_queued(p)) {
|
|
+ struct task_struct *first;
|
|
+
|
|
+ requeue_task(p, rq);
|
|
+
|
|
+ /* Resched if first queued task not running and not IDLE */
|
|
+ if ((first = rq_first_queued_task(rq)) != rq->curr &&
|
|
+ !task_running_idle(first))
|
|
+ resched_curr(rq);
|
|
+ }
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_RT_MUTEXES
|
|
+
|
|
+static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
|
|
+{
|
|
+ if (pi_task)
|
|
+ prio = min(prio, pi_task->prio);
|
|
+
|
|
+ return prio;
|
|
+}
|
|
+
|
|
+static inline int rt_effective_prio(struct task_struct *p, int prio)
|
|
+{
|
|
+ struct task_struct *pi_task = rt_mutex_get_top_task(p);
|
|
+
|
|
+ return __rt_effective_prio(pi_task, prio);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * rt_mutex_setprio - set the current priority of a task
|
|
+ * @p: task to boost
|
|
+ * @pi_task: donor task
|
|
+ *
|
|
+ * This function changes the 'effective' priority of a task. It does
|
|
+ * not touch ->normal_prio like __setscheduler().
|
|
+ *
|
|
+ * Used by the rt_mutex code to implement priority inheritance
|
|
+ * logic. Call site only calls if the priority of the task changed.
|
|
+ */
|
|
+void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
|
|
+{
|
|
+ int prio;
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+
|
|
+ /* XXX used to be waiter->prio, not waiter->task->prio */
|
|
+ prio = __rt_effective_prio(pi_task, p->normal_prio);
|
|
+
|
|
+ /*
|
|
+ * If nothing changed; bail early.
|
|
+ */
|
|
+ if (p->pi_top_task == pi_task && prio == p->prio)
|
|
+ return;
|
|
+
|
|
+ rq = __task_access_lock(p, &lock);
|
|
+ /*
|
|
+ * Set under pi_lock && rq->lock, such that the value can be used under
|
|
+ * either lock.
|
|
+ *
|
|
+ * Note that there is loads of tricky to make this pointer cache work
|
|
+ * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
|
|
+ * ensure a task is de-boosted (pi_task is set to NULL) before the
|
|
+ * task is allowed to run again (and can exit). This ensures the pointer
|
|
+ * points to a blocked task -- which guaratees the task is present.
|
|
+ */
|
|
+ p->pi_top_task = pi_task;
|
|
+
|
|
+ /*
|
|
+ * For FIFO/RR we only need to set prio, if that matches we're done.
|
|
+ */
|
|
+ if (prio == p->prio)
|
|
+ goto out_unlock;
|
|
+
|
|
+ /*
|
|
+ * Idle task boosting is a nono in general. There is one
|
|
+ * exception, when PREEMPT_RT and NOHZ is active:
|
|
+ *
|
|
+ * The idle task calls get_next_timer_interrupt() and holds
|
|
+ * the timer wheel base->lock on the CPU and another CPU wants
|
|
+ * to access the timer (probably to cancel it). We can safely
|
|
+ * ignore the boosting request, as the idle CPU runs this code
|
|
+ * with interrupts disabled and will complete the lock
|
|
+ * protected section without being interrupted. So there is no
|
|
+ * real need to boost.
|
|
+ */
|
|
+ if (unlikely(p == rq->idle)) {
|
|
+ WARN_ON(p != rq->curr);
|
|
+ WARN_ON(p->pi_blocked_on);
|
|
+ goto out_unlock;
|
|
+ }
|
|
+
|
|
+ trace_sched_pi_setprio(p, pi_task);
|
|
+ p->prio = prio;
|
|
+ update_task_priodl(p);
|
|
+
|
|
+ check_task_changed(rq, p);
|
|
+
|
|
+out_unlock:
|
|
+ __task_access_unlock(p, lock);
|
|
+}
|
|
+#else
|
|
+static inline int rt_effective_prio(struct task_struct *p, int prio)
|
|
+{
|
|
+ return prio;
|
|
+}
|
|
+#endif
|
|
+
|
|
+void set_user_nice(struct task_struct *p, long nice)
|
|
+{
|
|
+ int new_static;
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+
|
|
+ if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
|
|
+ return;
|
|
+ new_static = NICE_TO_PRIO(nice);
|
|
+ /*
|
|
+ * We have to be careful, if called from sys_setpriority(),
|
|
+ * the task might be in the middle of scheduling on another CPU.
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+ rq = __task_access_lock(p, &lock);
|
|
+
|
|
+ /* rq lock may not held!! */
|
|
+ update_rq_clock(rq);
|
|
+
|
|
+ p->static_prio = new_static;
|
|
+ /*
|
|
+ * The RT priorities are set via sched_setscheduler(), but we still
|
|
+ * allow the 'normal' nice value to be set - but as expected
|
|
+ * it wont have any effect on scheduling until the task is
|
|
+ * not SCHED_NORMAL/SCHED_BATCH:
|
|
+ */
|
|
+ if (task_has_rt_policy(p))
|
|
+ goto out_unlock;
|
|
+
|
|
+ p->deadline -= task_deadline_diff(p);
|
|
+ p->deadline += static_deadline_diff(new_static);
|
|
+ p->prio = effective_prio(p);
|
|
+ update_task_priodl(p);
|
|
+
|
|
+ check_task_changed(rq, p);
|
|
+out_unlock:
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+}
|
|
+EXPORT_SYMBOL(set_user_nice);
|
|
+
|
|
+/*
|
|
+ * can_nice - check if a task can reduce its nice value
|
|
+ * @p: task
|
|
+ * @nice: nice value
|
|
+ */
|
|
+int can_nice(const struct task_struct *p, const int nice)
|
|
+{
|
|
+ /* Convert nice value [19,-20] to rlimit style value [1,40] */
|
|
+ int nice_rlim = nice_to_rlimit(nice);
|
|
+
|
|
+ return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
|
|
+ capable(CAP_SYS_NICE));
|
|
+}
|
|
+
|
|
+#ifdef __ARCH_WANT_SYS_NICE
|
|
+
|
|
+/*
|
|
+ * sys_nice - change the priority of the current process.
|
|
+ * @increment: priority increment
|
|
+ *
|
|
+ * sys_setpriority is a more generic, but much slower function that
|
|
+ * does similar things.
|
|
+ */
|
|
+SYSCALL_DEFINE1(nice, int, increment)
|
|
+{
|
|
+ long nice, retval;
|
|
+
|
|
+ /*
|
|
+ * Setpriority might change our priority at the same moment.
|
|
+ * We don't have to worry. Conceptually one call occurs first
|
|
+ * and we have a single winner.
|
|
+ */
|
|
+
|
|
+ increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
|
|
+ nice = task_nice(current) + increment;
|
|
+
|
|
+ nice = clamp_val(nice, MIN_NICE, MAX_NICE);
|
|
+ if (increment < 0 && !can_nice(current, nice))
|
|
+ return -EPERM;
|
|
+
|
|
+ retval = security_task_setnice(current, nice);
|
|
+ if (retval)
|
|
+ return retval;
|
|
+
|
|
+ set_user_nice(current, nice);
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+#endif
|
|
+
|
|
+/**
|
|
+ * task_prio - return the priority value of a given task.
|
|
+ * @p: the task in question.
|
|
+ *
|
|
+ * Return: The priority value as seen by users in /proc.
|
|
+ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes
|
|
+ * from 0(SCHED_ISO) up to 82 (nice +19 SCHED_IDLE).
|
|
+ */
|
|
+int task_prio(const struct task_struct *p)
|
|
+{
|
|
+ int level, prio = p->prio - MAX_RT_PRIO;
|
|
+ static const int level_to_nice_prio[] = {39, 33, 26, 20, 14, 7, 0, 0};
|
|
+
|
|
+ /* rt tasks */
|
|
+ if (prio <= 0)
|
|
+ goto out;
|
|
+
|
|
+ preempt_disable();
|
|
+ level = task_deadline_level(p, this_rq());
|
|
+ preempt_enable();
|
|
+ prio += level_to_nice_prio[level];
|
|
+ if (idleprio_task(p))
|
|
+ prio += NICE_WIDTH;
|
|
+out:
|
|
+ return prio;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * idle_cpu - is a given CPU idle currently?
|
|
+ * @cpu: the processor in question.
|
|
+ *
|
|
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
|
|
+ */
|
|
+int idle_cpu(int cpu)
|
|
+{
|
|
+ return cpu_curr(cpu) == cpu_rq(cpu)->idle;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * idle_task - return the idle task for a given CPU.
|
|
+ * @cpu: the processor in question.
|
|
+ *
|
|
+ * Return: The idle task for the cpu @cpu.
|
|
+ */
|
|
+struct task_struct *idle_task(int cpu)
|
|
+{
|
|
+ return cpu_rq(cpu)->idle;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * find_process_by_pid - find a process with a matching PID value.
|
|
+ * @pid: the pid in question.
|
|
+ *
|
|
+ * The task of @pid, if found. %NULL otherwise.
|
|
+ */
|
|
+static inline struct task_struct *find_process_by_pid(pid_t pid)
|
|
+{
|
|
+ return pid ? find_task_by_vpid(pid) : current;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+void sched_set_stop_task(int cpu, struct task_struct *stop)
|
|
+{
|
|
+ struct sched_param stop_param = { .sched_priority = STOP_PRIO };
|
|
+ struct sched_param start_param = { .sched_priority = 0 };
|
|
+ struct task_struct *old_stop = cpu_rq(cpu)->stop;
|
|
+
|
|
+ if (stop) {
|
|
+ /*
|
|
+ * Make it appear like a SCHED_FIFO task, its something
|
|
+ * userspace knows about and won't get confused about.
|
|
+ *
|
|
+ * Also, it will make PI more or less work without too
|
|
+ * much confusion -- but then, stop work should not
|
|
+ * rely on PI working anyway.
|
|
+ */
|
|
+ sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param);
|
|
+ }
|
|
+
|
|
+ cpu_rq(cpu)->stop = stop;
|
|
+
|
|
+ if (old_stop) {
|
|
+ /*
|
|
+ * Reset it back to a normal scheduling policy so that
|
|
+ * it can die in pieces.
|
|
+ */
|
|
+ sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param);
|
|
+ }
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Change a given task's CPU affinity. Migrate the thread to a
|
|
+ * proper CPU and schedule it away if the CPU it's executing on
|
|
+ * is removed from the allowed bitmask.
|
|
+ *
|
|
+ * NOTE: the caller must have a valid reference to the task, the
|
|
+ * task must not exit() & deallocate itself prematurely. The
|
|
+ * call is not atomic; no spinlocks may be held.
|
|
+ */
|
|
+static int __set_cpus_allowed_ptr(struct task_struct *p,
|
|
+ const struct cpumask *new_mask, bool check)
|
|
+{
|
|
+ const struct cpumask *cpu_valid_mask = cpu_active_mask;
|
|
+ int dest_cpu;
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+ raw_spinlock_t *lock;
|
|
+ int ret = 0;
|
|
+
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+ rq = __task_access_lock(p, &lock);
|
|
+
|
|
+ if (p->flags & PF_KTHREAD) {
|
|
+ /*
|
|
+ * Kernel threads are allowed on online && !active CPUs
|
|
+ */
|
|
+ cpu_valid_mask = cpu_online_mask;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * Must re-check here, to close a race against __kthread_bind(),
|
|
+ * sched_setaffinity() is not guaranteed to observe the flag.
|
|
+ */
|
|
+ if (check && (p->flags & PF_NO_SETAFFINITY)) {
|
|
+ ret = -EINVAL;
|
|
+ goto out;
|
|
+ }
|
|
+
|
|
+ if (cpumask_equal(&p->cpus_mask, new_mask))
|
|
+ goto out;
|
|
+
|
|
+ dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
|
|
+ if (dest_cpu >= nr_cpu_ids) {
|
|
+ ret = -EINVAL;
|
|
+ goto out;
|
|
+ }
|
|
+
|
|
+ do_set_cpus_allowed(p, new_mask);
|
|
+
|
|
+ if (p->flags & PF_KTHREAD) {
|
|
+ /*
|
|
+ * For kernel threads that do indeed end up on online &&
|
|
+ * !active we want to ensure they are strict per-CPU threads.
|
|
+ */
|
|
+ WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) &&
|
|
+ !cpumask_intersects(new_mask, cpu_active_mask) &&
|
|
+ p->nr_cpus_allowed != 1);
|
|
+ }
|
|
+
|
|
+ /* Can the task run on the task's current CPU? If so, we're done */
|
|
+ if (cpumask_test_cpu(task_cpu(p), new_mask))
|
|
+ goto out;
|
|
+
|
|
+ if (task_running(p) || p->state == TASK_WAKING) {
|
|
+ struct migration_arg arg = { p, dest_cpu };
|
|
+
|
|
+ /* Need help from migration thread: drop lock and wait. */
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+ stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
|
|
+ return 0;
|
|
+ }
|
|
+ if (task_on_rq_queued(p)) {
|
|
+ /*
|
|
+ * OK, since we're going to drop the lock immediately
|
|
+ * afterwards anyway.
|
|
+ */
|
|
+ update_rq_clock(rq);
|
|
+ rq = move_queued_task(rq, p, dest_cpu);
|
|
+ lock = &rq->lock;
|
|
+ }
|
|
+
|
|
+out:
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
|
|
+{
|
|
+ return __set_cpus_allowed_ptr(p, new_mask, false);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
|
|
+
|
|
+#else
|
|
+static inline int
|
|
+__set_cpus_allowed_ptr(struct task_struct *p,
|
|
+ const struct cpumask *new_mask, bool check)
|
|
+{
|
|
+ return set_cpus_allowed_ptr(p, new_mask);
|
|
+}
|
|
+#endif
|
|
+
|
|
+static u64 task_init_deadline(const struct task_struct *p)
|
|
+{
|
|
+ return task_rq(p)->clock + task_deadline_diff(p);
|
|
+}
|
|
+
|
|
+u64 (* task_init_deadline_func_tbl[])(const struct task_struct *p) = {
|
|
+ task_init_deadline, /* SCHED_NORMAL */
|
|
+ NULL, /* SCHED_FIFO */
|
|
+ NULL, /* SCHED_RR */
|
|
+ task_init_deadline, /* SCHED_BATCH */
|
|
+ NULL, /* SCHED_ISO */
|
|
+ task_init_deadline /* SCHED_IDLE */
|
|
+};
|
|
+
|
|
+/*
|
|
+ * sched_setparam() passes in -1 for its policy, to let the functions
|
|
+ * it calls know not to change it.
|
|
+ */
|
|
+#define SETPARAM_POLICY -1
|
|
+
|
|
+static void __setscheduler_params(struct task_struct *p,
|
|
+ const struct sched_attr *attr)
|
|
+{
|
|
+ int old_policy = p->policy;
|
|
+ int policy = attr->sched_policy;
|
|
+
|
|
+ if (policy == SETPARAM_POLICY)
|
|
+ policy = p->policy;
|
|
+
|
|
+ p->policy = policy;
|
|
+
|
|
+ /*
|
|
+ * allow normal nice value to be set, but will not have any
|
|
+ * effect on scheduling until the task not SCHED_NORMAL/
|
|
+ * SCHED_BATCH
|
|
+ */
|
|
+ p->static_prio = NICE_TO_PRIO(attr->sched_nice);
|
|
+
|
|
+ /*
|
|
+ * __sched_setscheduler() ensures attr->sched_priority == 0 when
|
|
+ * !rt_policy. Always setting this ensures that things like
|
|
+ * getparam()/getattr() don't report silly values for !rt tasks.
|
|
+ */
|
|
+ p->rt_priority = attr->sched_priority;
|
|
+ p->normal_prio = normal_prio(p);
|
|
+
|
|
+ if (old_policy != policy)
|
|
+ p->deadline = (task_init_deadline_func_tbl[p->policy])?
|
|
+ task_init_deadline_func_tbl[p->policy](p):0ULL;
|
|
+}
|
|
+
|
|
+/* Actually do priority change: must hold rq lock. */
|
|
+static void __setscheduler(struct rq *rq, struct task_struct *p,
|
|
+ const struct sched_attr *attr, bool keep_boost)
|
|
+{
|
|
+ __setscheduler_params(p, attr);
|
|
+
|
|
+ /*
|
|
+ * Keep a potential priority boosting if called from
|
|
+ * sched_setscheduler().
|
|
+ */
|
|
+ p->prio = normal_prio(p);
|
|
+ if (keep_boost)
|
|
+ p->prio = rt_effective_prio(p, p->prio);
|
|
+ update_task_priodl(p);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * check the target process has a UID that matches the current process's
|
|
+ */
|
|
+static bool check_same_owner(struct task_struct *p)
|
|
+{
|
|
+ const struct cred *cred = current_cred(), *pcred;
|
|
+ bool match;
|
|
+
|
|
+ rcu_read_lock();
|
|
+ pcred = __task_cred(p);
|
|
+ match = (uid_eq(cred->euid, pcred->euid) ||
|
|
+ uid_eq(cred->euid, pcred->uid));
|
|
+ rcu_read_unlock();
|
|
+ return match;
|
|
+}
|
|
+
|
|
+static int
|
|
+__sched_setscheduler(struct task_struct *p,
|
|
+ const struct sched_attr *attr, bool user, bool pi)
|
|
+{
|
|
+ const struct sched_attr dl_squash_attr = {
|
|
+ .size = sizeof(struct sched_attr),
|
|
+ .sched_policy = SCHED_FIFO,
|
|
+ .sched_nice = 0,
|
|
+ .sched_priority = 99,
|
|
+ };
|
|
+ int newprio = MAX_RT_PRIO - 1 - attr->sched_priority;
|
|
+ int retval, oldpolicy = -1;
|
|
+ int policy = attr->sched_policy;
|
|
+ unsigned long flags;
|
|
+ struct rq *rq;
|
|
+ int reset_on_fork;
|
|
+ raw_spinlock_t *lock;
|
|
+
|
|
+ /* The pi code expects interrupts enabled */
|
|
+ BUG_ON(pi && in_interrupt());
|
|
+
|
|
+ /*
|
|
+ * PDS supports SCHED_DEADLINE by squash it as prio 0 SCHED_FIFO
|
|
+ */
|
|
+ if (unlikely(SCHED_DEADLINE == policy)) {
|
|
+ attr = &dl_squash_attr;
|
|
+ policy = attr->sched_policy;
|
|
+ newprio = MAX_RT_PRIO - 1 - attr->sched_priority;
|
|
+ }
|
|
+recheck:
|
|
+ /* Double check policy once rq lock held */
|
|
+ if (policy < 0) {
|
|
+ reset_on_fork = p->sched_reset_on_fork;
|
|
+ policy = oldpolicy = p->policy;
|
|
+ } else {
|
|
+ reset_on_fork = !!(attr->sched_flags & SCHED_RESET_ON_FORK);
|
|
+
|
|
+ if (policy > SCHED_IDLE)
|
|
+ return -EINVAL;
|
|
+ }
|
|
+
|
|
+ if (attr->sched_flags & ~(SCHED_FLAG_ALL))
|
|
+ return -EINVAL;
|
|
+
|
|
+ /*
|
|
+ * Valid priorities for SCHED_FIFO and SCHED_RR are
|
|
+ * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and
|
|
+ * SCHED_BATCH and SCHED_IDLE is 0.
|
|
+ */
|
|
+ if (attr->sched_priority < 0 ||
|
|
+ (p->mm && attr->sched_priority > MAX_USER_RT_PRIO - 1) ||
|
|
+ (!p->mm && attr->sched_priority > MAX_RT_PRIO - 1))
|
|
+ return -EINVAL;
|
|
+ if ((SCHED_RR == policy || SCHED_FIFO == policy) !=
|
|
+ (attr->sched_priority != 0))
|
|
+ return -EINVAL;
|
|
+
|
|
+ /*
|
|
+ * Allow unprivileged RT tasks to decrease priority:
|
|
+ */
|
|
+ if (user && !capable(CAP_SYS_NICE)) {
|
|
+ if (SCHED_FIFO == policy || SCHED_RR == policy) {
|
|
+ unsigned long rlim_rtprio =
|
|
+ task_rlimit(p, RLIMIT_RTPRIO);
|
|
+
|
|
+ /* Can't set/change the rt policy */
|
|
+ if (policy != p->policy && !rlim_rtprio)
|
|
+ return -EPERM;
|
|
+
|
|
+ /* Can't increase priority */
|
|
+ if (attr->sched_priority > p->rt_priority &&
|
|
+ attr->sched_priority > rlim_rtprio)
|
|
+ return -EPERM;
|
|
+ }
|
|
+
|
|
+ /* Can't change other user's priorities */
|
|
+ if (!check_same_owner(p))
|
|
+ return -EPERM;
|
|
+
|
|
+ /* Normal users shall not reset the sched_reset_on_fork flag */
|
|
+ if (p->sched_reset_on_fork && !reset_on_fork)
|
|
+ return -EPERM;
|
|
+ }
|
|
+
|
|
+ if (user) {
|
|
+ retval = security_task_setscheduler(p);
|
|
+ if (retval)
|
|
+ return retval;
|
|
+ }
|
|
+
|
|
+ if (pi)
|
|
+ cpuset_read_lock();
|
|
+
|
|
+ /*
|
|
+ * Make sure no PI-waiters arrive (or leave) while we are
|
|
+ * changing the priority of the task:
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&p->pi_lock, flags);
|
|
+
|
|
+ /*
|
|
+ * To be able to change p->policy safely, task_access_lock()
|
|
+ * must be called.
|
|
+ * IF use task_access_lock() here:
|
|
+ * For the task p which is not running, reading rq->stop is
|
|
+ * racy but acceptable as ->stop doesn't change much.
|
|
+ * An enhancemnet can be made to read rq->stop saftly.
|
|
+ */
|
|
+ rq = __task_access_lock(p, &lock);
|
|
+
|
|
+ /*
|
|
+ * Changing the policy of the stop threads its a very bad idea
|
|
+ */
|
|
+ if (p == rq->stop) {
|
|
+ retval = -EINVAL;
|
|
+ goto unlock;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * If not changing anything there's no need to proceed further:
|
|
+ */
|
|
+ if (unlikely(policy == p->policy)) {
|
|
+ if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
|
|
+ goto change;
|
|
+ if (!rt_policy(policy) &&
|
|
+ NICE_TO_PRIO(attr->sched_nice) != p->static_prio)
|
|
+ goto change;
|
|
+
|
|
+ p->sched_reset_on_fork = reset_on_fork;
|
|
+ retval = 0;
|
|
+ goto unlock;
|
|
+ }
|
|
+change:
|
|
+
|
|
+ /* Re-check policy now with rq lock held */
|
|
+ if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
|
|
+ policy = oldpolicy = -1;
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+ if (pi)
|
|
+ cpuset_read_unlock();
|
|
+ goto recheck;
|
|
+ }
|
|
+
|
|
+ p->sched_reset_on_fork = reset_on_fork;
|
|
+
|
|
+ if (pi) {
|
|
+ /*
|
|
+ * Take priority boosted tasks into account. If the new
|
|
+ * effective priority is unchanged, we just store the new
|
|
+ * normal parameters and do not touch the scheduler class and
|
|
+ * the runqueue. This will be done when the task deboost
|
|
+ * itself.
|
|
+ */
|
|
+ if (rt_effective_prio(p, newprio) == p->prio) {
|
|
+ __setscheduler_params(p, attr);
|
|
+ retval = 0;
|
|
+ goto unlock;
|
|
+ }
|
|
+ }
|
|
+
|
|
+ __setscheduler(rq, p, attr, pi);
|
|
+
|
|
+ check_task_changed(rq, p);
|
|
+
|
|
+ /* Avoid rq from going away on us: */
|
|
+ preempt_disable();
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+
|
|
+ if (pi) {
|
|
+ cpuset_read_unlock();
|
|
+ rt_mutex_adjust_pi(p);
|
|
+ }
|
|
+
|
|
+ preempt_enable();
|
|
+
|
|
+ return 0;
|
|
+
|
|
+unlock:
|
|
+ __task_access_unlock(p, lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, flags);
|
|
+ if (pi)
|
|
+ cpuset_read_unlock();
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+static int _sched_setscheduler(struct task_struct *p, int policy,
|
|
+ const struct sched_param *param, bool check)
|
|
+{
|
|
+ struct sched_attr attr = {
|
|
+ .sched_policy = policy,
|
|
+ .sched_priority = param->sched_priority,
|
|
+ .sched_nice = PRIO_TO_NICE(p->static_prio),
|
|
+ };
|
|
+
|
|
+ /* Fixup the legacy SCHED_RESET_ON_FORK hack. */
|
|
+ if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
|
|
+ attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
|
|
+ policy &= ~SCHED_RESET_ON_FORK;
|
|
+ attr.sched_policy = policy;
|
|
+ }
|
|
+
|
|
+ return __sched_setscheduler(p, &attr, check, true);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
|
|
+ * @p: the task in question.
|
|
+ * @policy: new policy.
|
|
+ * @param: structure containing the new RT priority.
|
|
+ *
|
|
+ * Return: 0 on success. An error code otherwise.
|
|
+ *
|
|
+ * NOTE that the task may be already dead.
|
|
+ */
|
|
+int sched_setscheduler(struct task_struct *p, int policy,
|
|
+ const struct sched_param *param)
|
|
+{
|
|
+ return _sched_setscheduler(p, policy, param, true);
|
|
+}
|
|
+
|
|
+EXPORT_SYMBOL_GPL(sched_setscheduler);
|
|
+
|
|
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
|
|
+{
|
|
+ return __sched_setscheduler(p, attr, true, true);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(sched_setattr);
|
|
+
|
|
+int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
|
|
+{
|
|
+ return __sched_setscheduler(p, attr, false, true);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
|
|
+ * @p: the task in question.
|
|
+ * @policy: new policy.
|
|
+ * @param: structure containing the new RT priority.
|
|
+ *
|
|
+ * Just like sched_setscheduler, only don't bother checking if the
|
|
+ * current context has permission. For example, this is needed in
|
|
+ * stop_machine(): we create temporary high priority worker threads,
|
|
+ * but our caller might not have that capability.
|
|
+ *
|
|
+ * Return: 0 on success. An error code otherwise.
|
|
+ */
|
|
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
|
|
+ const struct sched_param *param)
|
|
+{
|
|
+ return _sched_setscheduler(p, policy, param, false);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
|
|
+
|
|
+static int
|
|
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
|
|
+{
|
|
+ struct sched_param lparam;
|
|
+ struct task_struct *p;
|
|
+ int retval;
|
|
+
|
|
+ if (!param || pid < 0)
|
|
+ return -EINVAL;
|
|
+ if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
|
|
+ return -EFAULT;
|
|
+
|
|
+ rcu_read_lock();
|
|
+ retval = -ESRCH;
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (likely(p))
|
|
+ get_task_struct(p);
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ if (likely(p)) {
|
|
+ retval = sched_setscheduler(p, policy, &lparam);
|
|
+ put_task_struct(p);
|
|
+ }
|
|
+
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Mimics kernel/events/core.c perf_copy_attr().
|
|
+ */
|
|
+static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
|
|
+{
|
|
+ u32 size;
|
|
+ int ret;
|
|
+
|
|
+ /* Zero the full structure, so that a short copy will be nice: */
|
|
+ memset(attr, 0, sizeof(*attr));
|
|
+
|
|
+ ret = get_user(size, &uattr->size);
|
|
+ if (ret)
|
|
+ return ret;
|
|
+
|
|
+ /* ABI compatibility quirk: */
|
|
+ if (!size)
|
|
+ size = SCHED_ATTR_SIZE_VER0;
|
|
+
|
|
+ if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
|
|
+ goto err_size;
|
|
+
|
|
+ ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
|
|
+ if (ret) {
|
|
+ if (ret == -E2BIG)
|
|
+ goto err_size;
|
|
+ return ret;
|
|
+ }
|
|
+
|
|
+ /*
|
|
+ * XXX: Do we want to be lenient like existing syscalls; or do we want
|
|
+ * to be strict and return an error on out-of-bounds values?
|
|
+ */
|
|
+ attr->sched_nice = clamp(attr->sched_nice, -20, 19);
|
|
+
|
|
+ /* sched/core.c uses zero here but we already know ret is zero */
|
|
+ return 0;
|
|
+
|
|
+err_size:
|
|
+ put_user(sizeof(*attr), &uattr->size);
|
|
+ return -E2BIG;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
|
|
+ * @pid: the pid in question.
|
|
+ * @policy: new policy.
|
|
+ *
|
|
+ * Return: 0 on success. An error code otherwise.
|
|
+ * @param: structure containing the new RT priority.
|
|
+ */
|
|
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
|
|
+{
|
|
+ if (policy < 0)
|
|
+ return -EINVAL;
|
|
+
|
|
+ return do_sched_setscheduler(pid, policy, param);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_setparam - set/change the RT priority of a thread
|
|
+ * @pid: the pid in question.
|
|
+ * @param: structure containing the new RT priority.
|
|
+ *
|
|
+ * Return: 0 on success. An error code otherwise.
|
|
+ */
|
|
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
|
|
+{
|
|
+ return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_setattr - same as above, but with extended sched_attr
|
|
+ * @pid: the pid in question.
|
|
+ * @uattr: structure containing the extended parameters.
|
|
+ */
|
|
+SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
|
|
+ unsigned int, flags)
|
|
+{
|
|
+ struct sched_attr attr;
|
|
+ struct task_struct *p;
|
|
+ int retval;
|
|
+
|
|
+ if (!uattr || pid < 0 || flags)
|
|
+ return -EINVAL;
|
|
+
|
|
+ retval = sched_copy_attr(uattr, &attr);
|
|
+ if (retval)
|
|
+ return retval;
|
|
+
|
|
+ if ((int)attr.sched_policy < 0)
|
|
+ return -EINVAL;
|
|
+
|
|
+ rcu_read_lock();
|
|
+ retval = -ESRCH;
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (p != NULL)
|
|
+ retval = sched_setattr(p, &attr);
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
|
|
+ * @pid: the pid in question.
|
|
+ *
|
|
+ * Return: On success, the policy of the thread. Otherwise, a negative error
|
|
+ * code.
|
|
+ */
|
|
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
|
|
+{
|
|
+ struct task_struct *p;
|
|
+ int retval = -EINVAL;
|
|
+
|
|
+ if (pid < 0)
|
|
+ goto out_nounlock;
|
|
+
|
|
+ retval = -ESRCH;
|
|
+ rcu_read_lock();
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (p) {
|
|
+ retval = security_task_getscheduler(p);
|
|
+ if (!retval)
|
|
+ retval = p->policy;
|
|
+ }
|
|
+ rcu_read_unlock();
|
|
+
|
|
+out_nounlock:
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_getscheduler - get the RT priority of a thread
|
|
+ * @pid: the pid in question.
|
|
+ * @param: structure containing the RT priority.
|
|
+ *
|
|
+ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
|
|
+ * code.
|
|
+ */
|
|
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
|
|
+{
|
|
+ struct sched_param lp = { .sched_priority = 0 };
|
|
+ struct task_struct *p;
|
|
+ int retval = -EINVAL;
|
|
+
|
|
+ if (!param || pid < 0)
|
|
+ goto out_nounlock;
|
|
+
|
|
+ rcu_read_lock();
|
|
+ p = find_process_by_pid(pid);
|
|
+ retval = -ESRCH;
|
|
+ if (!p)
|
|
+ goto out_unlock;
|
|
+
|
|
+ retval = security_task_getscheduler(p);
|
|
+ if (retval)
|
|
+ goto out_unlock;
|
|
+
|
|
+ if (task_has_rt_policy(p))
|
|
+ lp.sched_priority = p->rt_priority;
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ /*
|
|
+ * This one might sleep, we cannot do it with a spinlock held ...
|
|
+ */
|
|
+ retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
|
|
+
|
|
+out_nounlock:
|
|
+ return retval;
|
|
+
|
|
+out_unlock:
|
|
+ rcu_read_unlock();
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Copy the kernel size attribute structure (which might be larger
|
|
+ * than what user-space knows about) to user-space.
|
|
+ *
|
|
+ * Note that all cases are valid: user-space buffer can be larger or
|
|
+ * smaller than the kernel-space buffer. The usual case is that both
|
|
+ * have the same size.
|
|
+ */
|
|
+static int
|
|
+sched_attr_copy_to_user(struct sched_attr __user *uattr,
|
|
+ struct sched_attr *kattr,
|
|
+ unsigned int usize)
|
|
+{
|
|
+ unsigned int ksize = sizeof(*kattr);
|
|
+
|
|
+ if (!access_ok(uattr, usize))
|
|
+ return -EFAULT;
|
|
+
|
|
+ /*
|
|
+ * sched_getattr() ABI forwards and backwards compatibility:
|
|
+ *
|
|
+ * If usize == ksize then we just copy everything to user-space and all is good.
|
|
+ *
|
|
+ * If usize < ksize then we only copy as much as user-space has space for,
|
|
+ * this keeps ABI compatibility as well. We skip the rest.
|
|
+ *
|
|
+ * If usize > ksize then user-space is using a newer version of the ABI,
|
|
+ * which part the kernel doesn't know about. Just ignore it - tooling can
|
|
+ * detect the kernel's knowledge of attributes from the attr->size value
|
|
+ * which is set to ksize in this case.
|
|
+ */
|
|
+ kattr->size = min(usize, ksize);
|
|
+
|
|
+ if (copy_to_user(uattr, kattr, kattr->size))
|
|
+ return -EFAULT;
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
|
|
+ * @pid: the pid in question.
|
|
+ * @uattr: structure containing the extended parameters.
|
|
+ * @usize: sizeof(attr) for fwd/bwd comp.
|
|
+ * @flags: for future extension.
|
|
+ */
|
|
+SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
|
|
+ unsigned int, usize, unsigned int, flags)
|
|
+{
|
|
+ struct sched_attr kattr = { };
|
|
+ struct task_struct *p;
|
|
+ int retval;
|
|
+
|
|
+ if (!uattr || pid < 0 || usize > PAGE_SIZE ||
|
|
+ usize < SCHED_ATTR_SIZE_VER0 || flags)
|
|
+ return -EINVAL;
|
|
+
|
|
+ rcu_read_lock();
|
|
+ p = find_process_by_pid(pid);
|
|
+ retval = -ESRCH;
|
|
+ if (!p)
|
|
+ goto out_unlock;
|
|
+
|
|
+ retval = security_task_getscheduler(p);
|
|
+ if (retval)
|
|
+ goto out_unlock;
|
|
+
|
|
+ kattr.sched_policy = p->policy;
|
|
+ if (rt_task(p))
|
|
+ kattr.sched_priority = p->rt_priority;
|
|
+ else
|
|
+ kattr.sched_nice = task_nice(p);
|
|
+
|
|
+#ifdef CONFIG_UCLAMP_TASK
|
|
+ kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
|
|
+ kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
|
|
+#endif
|
|
+
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ return sched_attr_copy_to_user(uattr, &kattr, usize);
|
|
+
|
|
+out_unlock:
|
|
+ rcu_read_unlock();
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
|
|
+{
|
|
+ cpumask_var_t cpus_mask, new_mask;
|
|
+ struct task_struct *p;
|
|
+ int retval;
|
|
+
|
|
+ get_online_cpus();
|
|
+ rcu_read_lock();
|
|
+
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (!p) {
|
|
+ rcu_read_unlock();
|
|
+ put_online_cpus();
|
|
+ return -ESRCH;
|
|
+ }
|
|
+
|
|
+ /* Prevent p going away */
|
|
+ get_task_struct(p);
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ if (p->flags & PF_NO_SETAFFINITY) {
|
|
+ retval = -EINVAL;
|
|
+ goto out_put_task;
|
|
+ }
|
|
+ if (!alloc_cpumask_var(&cpus_mask, GFP_KERNEL)) {
|
|
+ retval = -ENOMEM;
|
|
+ goto out_put_task;
|
|
+ }
|
|
+ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
|
|
+ retval = -ENOMEM;
|
|
+ goto out_free_cpus_allowed;
|
|
+ }
|
|
+ retval = -EPERM;
|
|
+ if (!check_same_owner(p)) {
|
|
+ rcu_read_lock();
|
|
+ if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
|
|
+ rcu_read_unlock();
|
|
+ goto out_unlock;
|
|
+ }
|
|
+ rcu_read_unlock();
|
|
+ }
|
|
+
|
|
+ retval = security_task_setscheduler(p);
|
|
+ if (retval)
|
|
+ goto out_unlock;
|
|
+
|
|
+ cpuset_cpus_allowed(p, cpus_mask);
|
|
+ cpumask_and(new_mask, in_mask, cpus_mask);
|
|
+again:
|
|
+ retval = __set_cpus_allowed_ptr(p, new_mask, true);
|
|
+
|
|
+ if (!retval) {
|
|
+ cpuset_cpus_allowed(p, cpus_mask);
|
|
+ if (!cpumask_subset(new_mask, cpus_mask)) {
|
|
+ /*
|
|
+ * We must have raced with a concurrent cpuset
|
|
+ * update. Just reset the cpus_mask to the
|
|
+ * cpuset's cpus_mask
|
|
+ */
|
|
+ cpumask_copy(new_mask, cpus_mask);
|
|
+ goto again;
|
|
+ }
|
|
+ }
|
|
+out_unlock:
|
|
+ free_cpumask_var(new_mask);
|
|
+out_free_cpus_allowed:
|
|
+ free_cpumask_var(cpus_mask);
|
|
+out_put_task:
|
|
+ put_task_struct(p);
|
|
+ put_online_cpus();
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
|
|
+ struct cpumask *new_mask)
|
|
+{
|
|
+ if (len < cpumask_size())
|
|
+ cpumask_clear(new_mask);
|
|
+ else if (len > cpumask_size())
|
|
+ len = cpumask_size();
|
|
+
|
|
+ return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_setaffinity - set the CPU affinity of a process
|
|
+ * @pid: pid of the process
|
|
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
|
|
+ * @user_mask_ptr: user-space pointer to the new CPU mask
|
|
+ *
|
|
+ * Return: 0 on success. An error code otherwise.
|
|
+ */
|
|
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
|
|
+ unsigned long __user *, user_mask_ptr)
|
|
+{
|
|
+ cpumask_var_t new_mask;
|
|
+ int retval;
|
|
+
|
|
+ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
|
|
+ return -ENOMEM;
|
|
+
|
|
+ retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
|
|
+ if (retval == 0)
|
|
+ retval = sched_setaffinity(pid, new_mask);
|
|
+ free_cpumask_var(new_mask);
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+long sched_getaffinity(pid_t pid, cpumask_t *mask)
|
|
+{
|
|
+ struct task_struct *p;
|
|
+ raw_spinlock_t *lock;
|
|
+ unsigned long flags;
|
|
+ int retval;
|
|
+
|
|
+ rcu_read_lock();
|
|
+
|
|
+ retval = -ESRCH;
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (!p)
|
|
+ goto out_unlock;
|
|
+
|
|
+ retval = security_task_getscheduler(p);
|
|
+ if (retval)
|
|
+ goto out_unlock;
|
|
+
|
|
+ task_access_lock_irqsave(p, &lock, &flags);
|
|
+ cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
|
|
+ task_access_unlock_irqrestore(p, lock, &flags);
|
|
+
|
|
+out_unlock:
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_getaffinity - get the CPU affinity of a process
|
|
+ * @pid: pid of the process
|
|
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
|
|
+ * @user_mask_ptr: user-space pointer to hold the current CPU mask
|
|
+ *
|
|
+ * Return: size of CPU mask copied to user_mask_ptr on success. An
|
|
+ * error code otherwise.
|
|
+ */
|
|
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
|
|
+ unsigned long __user *, user_mask_ptr)
|
|
+{
|
|
+ int ret;
|
|
+ cpumask_var_t mask;
|
|
+
|
|
+ if ((len * BITS_PER_BYTE) < nr_cpu_ids)
|
|
+ return -EINVAL;
|
|
+ if (len & (sizeof(unsigned long)-1))
|
|
+ return -EINVAL;
|
|
+
|
|
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL))
|
|
+ return -ENOMEM;
|
|
+
|
|
+ ret = sched_getaffinity(pid, mask);
|
|
+ if (ret == 0) {
|
|
+ unsigned int retlen = min_t(size_t, len, cpumask_size());
|
|
+
|
|
+ if (copy_to_user(user_mask_ptr, mask, retlen))
|
|
+ ret = -EFAULT;
|
|
+ else
|
|
+ ret = retlen;
|
|
+ }
|
|
+ free_cpumask_var(mask);
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_yield - yield the current processor to other threads.
|
|
+ *
|
|
+ * This function yields the current CPU to other tasks. It does this by
|
|
+ * scheduling away the current task. If it still has the earliest deadline
|
|
+ * it will be scheduled again as the next task.
|
|
+ *
|
|
+ * Return: 0.
|
|
+ */
|
|
+static void do_sched_yield(void)
|
|
+{
|
|
+ struct rq *rq;
|
|
+ struct rq_flags rf;
|
|
+
|
|
+ if (!sched_yield_type)
|
|
+ return;
|
|
+
|
|
+ rq = this_rq_lock_irq(&rf);
|
|
+
|
|
+ if (sched_yield_type > 1) {
|
|
+ time_slice_expired(current, rq);
|
|
+ requeue_task(current, rq);
|
|
+ }
|
|
+ schedstat_inc(rq->yld_count);
|
|
+
|
|
+ /*
|
|
+ * Since we are going to call schedule() anyway, there's
|
|
+ * no need to preempt or enable interrupts:
|
|
+ */
|
|
+ preempt_disable();
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ sched_preempt_enable_no_resched();
|
|
+
|
|
+ schedule();
|
|
+}
|
|
+
|
|
+SYSCALL_DEFINE0(sched_yield)
|
|
+{
|
|
+ do_sched_yield();
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+#ifndef CONFIG_PREEMPTION
|
|
+int __sched _cond_resched(void)
|
|
+{
|
|
+ if (should_resched(0)) {
|
|
+ preempt_schedule_common();
|
|
+ return 1;
|
|
+ }
|
|
+ rcu_all_qs();
|
|
+ return 0;
|
|
+}
|
|
+EXPORT_SYMBOL(_cond_resched);
|
|
+#endif
|
|
+
|
|
+/*
|
|
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
|
|
+ * call schedule, and on return reacquire the lock.
|
|
+ *
|
|
+ * This works OK both with and without CONFIG_PREEMPTION. We do strange low-level
|
|
+ * operations here to prevent schedule() from being called twice (once via
|
|
+ * spin_unlock(), once by hand).
|
|
+ */
|
|
+int __cond_resched_lock(spinlock_t *lock)
|
|
+{
|
|
+ int resched = should_resched(PREEMPT_LOCK_OFFSET);
|
|
+ int ret = 0;
|
|
+
|
|
+ lockdep_assert_held(lock);
|
|
+
|
|
+ if (spin_needbreak(lock) || resched) {
|
|
+ spin_unlock(lock);
|
|
+ if (resched)
|
|
+ preempt_schedule_common();
|
|
+ else
|
|
+ cpu_relax();
|
|
+ ret = 1;
|
|
+ spin_lock(lock);
|
|
+ }
|
|
+ return ret;
|
|
+}
|
|
+EXPORT_SYMBOL(__cond_resched_lock);
|
|
+
|
|
+/**
|
|
+ * yield - yield the current processor to other threads.
|
|
+ *
|
|
+ * Do not ever use this function, there's a 99% chance you're doing it wrong.
|
|
+ *
|
|
+ * The scheduler is at all times free to pick the calling task as the most
|
|
+ * eligible task to run, if removing the yield() call from your code breaks
|
|
+ * it, its already broken.
|
|
+ *
|
|
+ * Typical broken usage is:
|
|
+ *
|
|
+ * while (!event)
|
|
+ * yield();
|
|
+ *
|
|
+ * where one assumes that yield() will let 'the other' process run that will
|
|
+ * make event true. If the current task is a SCHED_FIFO task that will never
|
|
+ * happen. Never use yield() as a progress guarantee!!
|
|
+ *
|
|
+ * If you want to use yield() to wait for something, use wait_event().
|
|
+ * If you want to use yield() to be 'nice' for others, use cond_resched().
|
|
+ * If you still want to use yield(), do not!
|
|
+ */
|
|
+void __sched yield(void)
|
|
+{
|
|
+ set_current_state(TASK_RUNNING);
|
|
+ do_sched_yield();
|
|
+}
|
|
+EXPORT_SYMBOL(yield);
|
|
+
|
|
+/**
|
|
+ * yield_to - yield the current processor to another thread in
|
|
+ * your thread group, or accelerate that thread toward the
|
|
+ * processor it's on.
|
|
+ * @p: target task
|
|
+ * @preempt: whether task preemption is allowed or not
|
|
+ *
|
|
+ * It's the caller's job to ensure that the target task struct
|
|
+ * can't go away on us before we can do any checks.
|
|
+ *
|
|
+ * In PDS, yield_to is not supported.
|
|
+ *
|
|
+ * Return:
|
|
+ * true (>0) if we indeed boosted the target task.
|
|
+ * false (0) if we failed to boost the target.
|
|
+ * -ESRCH if there's no task to yield to.
|
|
+ */
|
|
+int __sched yield_to(struct task_struct *p, bool preempt)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(yield_to);
|
|
+
|
|
+int io_schedule_prepare(void)
|
|
+{
|
|
+ int old_iowait = current->in_iowait;
|
|
+
|
|
+ current->in_iowait = 1;
|
|
+ blk_schedule_flush_plug(current);
|
|
+
|
|
+ return old_iowait;
|
|
+}
|
|
+
|
|
+void io_schedule_finish(int token)
|
|
+{
|
|
+ current->in_iowait = token;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * This task is about to go to sleep on IO. Increment rq->nr_iowait so
|
|
+ * that process accounting knows that this is a task in IO wait state.
|
|
+ *
|
|
+ * But don't do that if it is a deliberate, throttling IO wait (this task
|
|
+ * has set its backing_dev_info: the queue against which it should throttle)
|
|
+ */
|
|
+
|
|
+long __sched io_schedule_timeout(long timeout)
|
|
+{
|
|
+ int token;
|
|
+ long ret;
|
|
+
|
|
+ token = io_schedule_prepare();
|
|
+ ret = schedule_timeout(timeout);
|
|
+ io_schedule_finish(token);
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+EXPORT_SYMBOL(io_schedule_timeout);
|
|
+
|
|
+void io_schedule(void)
|
|
+{
|
|
+ int token;
|
|
+
|
|
+ token = io_schedule_prepare();
|
|
+ schedule();
|
|
+ io_schedule_finish(token);
|
|
+}
|
|
+EXPORT_SYMBOL(io_schedule);
|
|
+
|
|
+/**
|
|
+ * sys_sched_get_priority_max - return maximum RT priority.
|
|
+ * @policy: scheduling class.
|
|
+ *
|
|
+ * Return: On success, this syscall returns the maximum
|
|
+ * rt_priority that can be used by a given scheduling class.
|
|
+ * On failure, a negative error code is returned.
|
|
+ */
|
|
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
|
|
+{
|
|
+ int ret = -EINVAL;
|
|
+
|
|
+ switch (policy) {
|
|
+ case SCHED_FIFO:
|
|
+ case SCHED_RR:
|
|
+ ret = MAX_USER_RT_PRIO-1;
|
|
+ break;
|
|
+ case SCHED_NORMAL:
|
|
+ case SCHED_BATCH:
|
|
+ case SCHED_ISO:
|
|
+ case SCHED_IDLE:
|
|
+ ret = 0;
|
|
+ break;
|
|
+ }
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_get_priority_min - return minimum RT priority.
|
|
+ * @policy: scheduling class.
|
|
+ *
|
|
+ * Return: On success, this syscall returns the minimum
|
|
+ * rt_priority that can be used by a given scheduling class.
|
|
+ * On failure, a negative error code is returned.
|
|
+ */
|
|
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
|
|
+{
|
|
+ int ret = -EINVAL;
|
|
+
|
|
+ switch (policy) {
|
|
+ case SCHED_FIFO:
|
|
+ case SCHED_RR:
|
|
+ ret = 1;
|
|
+ break;
|
|
+ case SCHED_NORMAL:
|
|
+ case SCHED_BATCH:
|
|
+ case SCHED_ISO:
|
|
+ case SCHED_IDLE:
|
|
+ ret = 0;
|
|
+ break;
|
|
+ }
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
|
|
+{
|
|
+ struct task_struct *p;
|
|
+ int retval;
|
|
+
|
|
+ if (pid < 0)
|
|
+ return -EINVAL;
|
|
+
|
|
+ retval = -ESRCH;
|
|
+ rcu_read_lock();
|
|
+ p = find_process_by_pid(pid);
|
|
+ if (!p)
|
|
+ goto out_unlock;
|
|
+
|
|
+ retval = security_task_getscheduler(p);
|
|
+ if (retval)
|
|
+ goto out_unlock;
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ *t = ns_to_timespec64(MS_TO_NS(rr_interval));
|
|
+ return 0;
|
|
+
|
|
+out_unlock:
|
|
+ rcu_read_unlock();
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
|
|
+ * @pid: pid of the process.
|
|
+ * @interval: userspace pointer to the timeslice value.
|
|
+ *
|
|
+ *
|
|
+ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
|
|
+ * an error code.
|
|
+ */
|
|
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
|
|
+ struct __kernel_timespec __user *, interval)
|
|
+{
|
|
+ struct timespec64 t;
|
|
+ int retval = sched_rr_get_interval(pid, &t);
|
|
+
|
|
+ if (retval == 0)
|
|
+ retval = put_timespec64(&t, interval);
|
|
+
|
|
+ return retval;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_COMPAT_32BIT_TIME
|
|
+SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
|
|
+ struct old_timespec32 __user *, interval)
|
|
+{
|
|
+ struct timespec64 t;
|
|
+ int retval = sched_rr_get_interval(pid, &t);
|
|
+
|
|
+ if (retval == 0)
|
|
+ retval = put_old_timespec32(&t, interval);
|
|
+ return retval;
|
|
+}
|
|
+#endif
|
|
+
|
|
+void sched_show_task(struct task_struct *p)
|
|
+{
|
|
+ unsigned long free = 0;
|
|
+ int ppid;
|
|
+
|
|
+ if (!try_get_task_stack(p))
|
|
+ return;
|
|
+
|
|
+ printk(KERN_INFO "%-15.15s %c", p->comm, task_state_to_char(p));
|
|
+
|
|
+ if (p->state == TASK_RUNNING)
|
|
+ printk(KERN_CONT " running task ");
|
|
+#ifdef CONFIG_DEBUG_STACK_USAGE
|
|
+ free = stack_not_used(p);
|
|
+#endif
|
|
+ ppid = 0;
|
|
+ rcu_read_lock();
|
|
+ if (pid_alive(p))
|
|
+ ppid = task_pid_nr(rcu_dereference(p->real_parent));
|
|
+ rcu_read_unlock();
|
|
+ printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
|
|
+ task_pid_nr(p), ppid,
|
|
+ (unsigned long)task_thread_info(p)->flags);
|
|
+
|
|
+ print_worker_info(KERN_INFO, p);
|
|
+ show_stack(p, NULL);
|
|
+ put_task_stack(p);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(sched_show_task);
|
|
+
|
|
+static inline bool
|
|
+state_filter_match(unsigned long state_filter, struct task_struct *p)
|
|
+{
|
|
+ /* no filter, everything matches */
|
|
+ if (!state_filter)
|
|
+ return true;
|
|
+
|
|
+ /* filter, but doesn't match */
|
|
+ if (!(p->state & state_filter))
|
|
+ return false;
|
|
+
|
|
+ /*
|
|
+ * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
|
|
+ * TASK_KILLABLE).
|
|
+ */
|
|
+ if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
|
|
+ return false;
|
|
+
|
|
+ return true;
|
|
+}
|
|
+
|
|
+
|
|
+void show_state_filter(unsigned long state_filter)
|
|
+{
|
|
+ struct task_struct *g, *p;
|
|
+
|
|
+#if BITS_PER_LONG == 32
|
|
+ printk(KERN_INFO
|
|
+ " task PC stack pid father\n");
|
|
+#else
|
|
+ printk(KERN_INFO
|
|
+ " task PC stack pid father\n");
|
|
+#endif
|
|
+ rcu_read_lock();
|
|
+ for_each_process_thread(g, p) {
|
|
+ /*
|
|
+ * reset the NMI-timeout, listing all files on a slow
|
|
+ * console might take a lot of time:
|
|
+ * Also, reset softlockup watchdogs on all CPUs, because
|
|
+ * another CPU might be blocked waiting for us to process
|
|
+ * an IPI.
|
|
+ */
|
|
+ touch_nmi_watchdog();
|
|
+ touch_all_softlockup_watchdogs();
|
|
+ if (state_filter_match(state_filter, p))
|
|
+ sched_show_task(p);
|
|
+ }
|
|
+
|
|
+#ifdef CONFIG_SCHED_DEBUG
|
|
+ /* PDS TODO: should support this
|
|
+ if (!state_filter)
|
|
+ sysrq_sched_debug_show();
|
|
+ */
|
|
+#endif
|
|
+ rcu_read_unlock();
|
|
+ /*
|
|
+ * Only show locks if all tasks are dumped:
|
|
+ */
|
|
+ if (!state_filter)
|
|
+ debug_show_all_locks();
|
|
+}
|
|
+
|
|
+void dump_cpu_task(int cpu)
|
|
+{
|
|
+ pr_info("Task dump for CPU %d:\n", cpu);
|
|
+ sched_show_task(cpu_curr(cpu));
|
|
+}
|
|
+
|
|
+/**
|
|
+ * init_idle - set up an idle thread for a given CPU
|
|
+ * @idle: task in question
|
|
+ * @cpu: cpu the idle task belongs to
|
|
+ *
|
|
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
|
|
+ * flag, to make booting more robust.
|
|
+ */
|
|
+void init_idle(struct task_struct *idle, int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+
|
|
+ raw_spin_lock_irqsave(&idle->pi_lock, flags);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ update_rq_clock(rq);
|
|
+
|
|
+ idle->last_ran = rq->clock_task;
|
|
+ idle->state = TASK_RUNNING;
|
|
+ idle->flags |= PF_IDLE;
|
|
+ /* Setting prio to illegal value shouldn't matter when never queued */
|
|
+ idle->prio = PRIO_LIMIT;
|
|
+ idle->deadline = rq_clock(rq) + task_deadline_diff(idle);
|
|
+ update_task_priodl(idle);
|
|
+
|
|
+ kasan_unpoison_task_stack(idle);
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ /*
|
|
+ * It's possible that init_idle() gets called multiple times on a task,
|
|
+ * in that case do_set_cpus_allowed() will not do the right thing.
|
|
+ *
|
|
+ * And since this is boot we can forgo the serialisation.
|
|
+ */
|
|
+ set_cpus_allowed_common(idle, cpumask_of(cpu));
|
|
+#endif
|
|
+
|
|
+ /* Silence PROVE_RCU */
|
|
+ rcu_read_lock();
|
|
+ __set_task_cpu(idle, cpu);
|
|
+ rcu_read_unlock();
|
|
+
|
|
+ rq->idle = idle;
|
|
+ rcu_assign_pointer(rq->curr, idle);
|
|
+ idle->on_cpu = 1;
|
|
+
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
|
|
+
|
|
+ /* Set the preempt count _outside_ the spinlocks! */
|
|
+ init_idle_preempt_count(idle, cpu);
|
|
+
|
|
+ ftrace_graph_init_idle_task(idle, cpu);
|
|
+ vtime_init_idle(idle, cpu);
|
|
+#ifdef CONFIG_SMP
|
|
+ sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
|
|
+#endif
|
|
+}
|
|
+
|
|
+void resched_cpu(int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ if (cpu_online(cpu) || cpu == smp_processor_id())
|
|
+ resched_curr(cpu_rq(cpu));
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+}
|
|
+
|
|
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
|
|
+{
|
|
+ struct wake_q_node *node = &task->wake_q;
|
|
+
|
|
+ /*
|
|
+ * Atomically grab the task, if ->wake_q is !nil already it means
|
|
+ * its already queued (either by us or someone else) and will get the
|
|
+ * wakeup due to that.
|
|
+ *
|
|
+ * In order to ensure that a pending wakeup will observe our pending
|
|
+ * state, even in the failed case, an explicit smp_mb() must be used.
|
|
+ */
|
|
+ smp_mb__before_atomic();
|
|
+ if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
|
|
+ return false;
|
|
+
|
|
+ /*
|
|
+ * The head is context local, there can be no concurrency.
|
|
+ */
|
|
+ *head->lastp = node;
|
|
+ head->lastp = &node->next;
|
|
+ return true;
|
|
+}
|
|
+
|
|
+/**
|
|
+ * wake_q_add() - queue a wakeup for 'later' waking.
|
|
+ * @head: the wake_q_head to add @task to
|
|
+ * @task: the task to queue for 'later' wakeup
|
|
+ *
|
|
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
|
|
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
|
|
+ * instantly.
|
|
+ *
|
|
+ * This function must be used as-if it were wake_up_process(); IOW the task
|
|
+ * must be ready to be woken at this location.
|
|
+ */
|
|
+void wake_q_add(struct wake_q_head *head, struct task_struct *task)
|
|
+{
|
|
+ if (__wake_q_add(head, task))
|
|
+ get_task_struct(task);
|
|
+}
|
|
+
|
|
+/**
|
|
+ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
|
|
+ * @head: the wake_q_head to add @task to
|
|
+ * @task: the task to queue for 'later' wakeup
|
|
+ *
|
|
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
|
|
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
|
|
+ * instantly.
|
|
+ *
|
|
+ * This function must be used as-if it were wake_up_process(); IOW the task
|
|
+ * must be ready to be woken at this location.
|
|
+ *
|
|
+ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
|
|
+ * that already hold reference to @task can call the 'safe' version and trust
|
|
+ * wake_q to do the right thing depending whether or not the @task is already
|
|
+ * queued for wakeup.
|
|
+ */
|
|
+void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
|
|
+{
|
|
+ if (!__wake_q_add(head, task))
|
|
+ put_task_struct(task);
|
|
+}
|
|
+
|
|
+void wake_up_q(struct wake_q_head *head)
|
|
+{
|
|
+ struct wake_q_node *node = head->first;
|
|
+
|
|
+ while (node != WAKE_Q_TAIL) {
|
|
+ struct task_struct *task;
|
|
+
|
|
+ task = container_of(node, struct task_struct, wake_q);
|
|
+ BUG_ON(!task);
|
|
+ /* task can safely be re-inserted now: */
|
|
+ node = node->next;
|
|
+ task->wake_q.next = NULL;
|
|
+
|
|
+ /*
|
|
+ * wake_up_process() executes a full barrier, which pairs with
|
|
+ * the queueing in wake_q_add() so as not to miss wakeups.
|
|
+ */
|
|
+ wake_up_process(task);
|
|
+ put_task_struct(task);
|
|
+ }
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+
|
|
+int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur,
|
|
+ const struct cpumask __maybe_unused *trial)
|
|
+{
|
|
+ return 1;
|
|
+}
|
|
+
|
|
+int task_can_attach(struct task_struct *p,
|
|
+ const struct cpumask *cs_cpus_allowed)
|
|
+{
|
|
+ int ret = 0;
|
|
+
|
|
+ /*
|
|
+ * Kthreads which disallow setaffinity shouldn't be moved
|
|
+ * to a new cpuset; we don't want to change their CPU
|
|
+ * affinity and isolating such threads by their set of
|
|
+ * allowed nodes is unnecessary. Thus, cpusets are not
|
|
+ * applicable for such threads. This prevents checking for
|
|
+ * success of set_cpus_allowed_ptr() on all attached tasks
|
|
+ * before cpus_mask may be changed.
|
|
+ */
|
|
+ if (p->flags & PF_NO_SETAFFINITY)
|
|
+ ret = -EINVAL;
|
|
+
|
|
+ return ret;
|
|
+}
|
|
+
|
|
+static bool sched_smp_initialized __read_mostly;
|
|
+
|
|
+#ifdef CONFIG_NO_HZ_COMMON
|
|
+void nohz_balance_enter_idle(int cpu)
|
|
+{
|
|
+}
|
|
+
|
|
+void select_nohz_load_balancer(int stop_tick)
|
|
+{
|
|
+}
|
|
+
|
|
+void set_cpu_sd_state_idle(void) {}
|
|
+
|
|
+/*
|
|
+ * In the semi idle case, use the nearest busy CPU for migrating timers
|
|
+ * from an idle CPU. This is good for power-savings.
|
|
+ *
|
|
+ * We don't do similar optimization for completely idle system, as
|
|
+ * selecting an idle CPU will add more delays to the timers than intended
|
|
+ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
|
|
+ */
|
|
+int get_nohz_timer_target(void)
|
|
+{
|
|
+ int i, cpu = smp_processor_id();
|
|
+ struct cpumask *mask;
|
|
+
|
|
+ if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER))
|
|
+ return cpu;
|
|
+
|
|
+ for (mask = &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[0]);
|
|
+ mask < per_cpu(sched_cpu_affinity_chk_end_masks, cpu); mask++)
|
|
+ for_each_cpu(i, mask)
|
|
+ if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER))
|
|
+ return i;
|
|
+
|
|
+ if (!housekeeping_cpu(cpu, HK_FLAG_TIMER))
|
|
+ cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
|
|
+
|
|
+ return cpu;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * When add_timer_on() enqueues a timer into the timer wheel of an
|
|
+ * idle CPU then this timer might expire before the next timer event
|
|
+ * which is scheduled to wake up that CPU. In case of a completely
|
|
+ * idle system the next event might even be infinite time into the
|
|
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
|
|
+ * leaves the inner idle loop so the newly added timer is taken into
|
|
+ * account when the CPU goes back to idle and evaluates the timer
|
|
+ * wheel for the next timer event.
|
|
+ */
|
|
+void wake_up_idle_cpu(int cpu)
|
|
+{
|
|
+ if (cpu == smp_processor_id())
|
|
+ return;
|
|
+
|
|
+ set_tsk_need_resched(cpu_rq(cpu)->idle);
|
|
+ smp_send_reschedule(cpu);
|
|
+}
|
|
+
|
|
+void wake_up_nohz_cpu(int cpu)
|
|
+{
|
|
+ wake_up_idle_cpu(cpu);
|
|
+}
|
|
+#endif /* CONFIG_NO_HZ_COMMON */
|
|
+
|
|
+#ifdef CONFIG_HOTPLUG_CPU
|
|
+/*
|
|
+ * Ensures that the idle task is using init_mm right before its CPU goes
|
|
+ * offline.
|
|
+ */
|
|
+void idle_task_exit(void)
|
|
+{
|
|
+ struct mm_struct *mm = current->active_mm;
|
|
+
|
|
+ BUG_ON(cpu_online(smp_processor_id()));
|
|
+
|
|
+ if (mm != &init_mm) {
|
|
+ switch_mm(mm, &init_mm, current);
|
|
+ current->active_mm = &init_mm;
|
|
+ finish_arch_post_lock_switch();
|
|
+ }
|
|
+ mmdrop(mm);
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Migrate all tasks from the rq, sleeping tasks will be migrated by
|
|
+ * try_to_wake_up()->select_task_rq().
|
|
+ *
|
|
+ * Called with rq->lock held even though we'er in stop_machine() and
|
|
+ * there's no concurrency possible, we hold the required locks anyway
|
|
+ * because of lock validation efforts.
|
|
+ */
|
|
+static void migrate_tasks(struct rq *dead_rq)
|
|
+{
|
|
+ struct rq *rq = dead_rq;
|
|
+ struct task_struct *p, *stop = rq->stop;
|
|
+ struct skiplist_node *node;
|
|
+ int count = 0;
|
|
+
|
|
+ /*
|
|
+ * Fudge the rq selection such that the below task selection loop
|
|
+ * doesn't get stuck on the currently eligible stop task.
|
|
+ *
|
|
+ * We're currently inside stop_machine() and the rq is either stuck
|
|
+ * in the stop_machine_cpu_stop() loop, or we're executing this code,
|
|
+ * either way we should never end up calling schedule() until we're
|
|
+ * done here.
|
|
+ */
|
|
+ rq->stop = NULL;
|
|
+
|
|
+ node = &rq->sl_header;
|
|
+ while ((node = node->next[0]) != &rq->sl_header) {
|
|
+ int dest_cpu;
|
|
+
|
|
+ p = skiplist_entry(node, struct task_struct, sl_node);
|
|
+
|
|
+ /* skip the running task */
|
|
+ if (task_running(p))
|
|
+ continue;
|
|
+
|
|
+ /*
|
|
+ * Rules for changing task_struct::cpus_mask are holding
|
|
+ * both pi_lock and rq->lock, such that holding either
|
|
+ * stabilizes the mask.
|
|
+ *
|
|
+ * Drop rq->lock is not quite as disastrous as it usually is
|
|
+ * because !cpu_active at this point, which means load-balance
|
|
+ * will not interfere. Also, stop-machine.
|
|
+ */
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_lock(&p->pi_lock);
|
|
+ raw_spin_lock(&rq->lock);
|
|
+
|
|
+ /*
|
|
+ * Since we're inside stop-machine, _nothing_ should have
|
|
+ * changed the task, WARN if weird stuff happened, because in
|
|
+ * that case the above rq->lock drop is a fail too.
|
|
+ */
|
|
+ if (WARN_ON(task_rq(p) != rq || !task_on_rq_queued(p))) {
|
|
+ raw_spin_unlock(&p->pi_lock);
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ count++;
|
|
+ /* Find suitable destination for @next, with force if needed. */
|
|
+ dest_cpu = select_fallback_rq(dead_rq->cpu, p);
|
|
+
|
|
+ rq = __migrate_task(rq, p, dest_cpu);
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock(&p->pi_lock);
|
|
+
|
|
+ rq = dead_rq;
|
|
+ raw_spin_lock(&rq->lock);
|
|
+ /* Check queued task all over from the header again */
|
|
+ node = &rq->sl_header;
|
|
+ }
|
|
+
|
|
+ rq->stop = stop;
|
|
+}
|
|
+
|
|
+static void set_rq_offline(struct rq *rq)
|
|
+{
|
|
+ if (rq->online)
|
|
+ rq->online = false;
|
|
+}
|
|
+#endif /* CONFIG_HOTPLUG_CPU */
|
|
+
|
|
+static void set_rq_online(struct rq *rq)
|
|
+{
|
|
+ if (!rq->online)
|
|
+ rq->online = true;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_SCHED_DEBUG
|
|
+
|
|
+static __read_mostly int sched_debug_enabled;
|
|
+
|
|
+static int __init sched_debug_setup(char *str)
|
|
+{
|
|
+ sched_debug_enabled = 1;
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+early_param("sched_debug", sched_debug_setup);
|
|
+
|
|
+static inline bool sched_debug(void)
|
|
+{
|
|
+ return sched_debug_enabled;
|
|
+}
|
|
+#else /* !CONFIG_SCHED_DEBUG */
|
|
+static inline bool sched_debug(void)
|
|
+{
|
|
+ return false;
|
|
+}
|
|
+#endif /* CONFIG_SCHED_DEBUG */
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+void scheduler_ipi(void)
|
|
+{
|
|
+ /*
|
|
+ * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
|
|
+ * TIF_NEED_RESCHED remotely (for the first time) will also send
|
|
+ * this IPI.
|
|
+ */
|
|
+ preempt_fold_need_resched();
|
|
+
|
|
+ if (!idle_cpu(smp_processor_id()) || need_resched())
|
|
+ return;
|
|
+
|
|
+ irq_enter();
|
|
+ irq_exit();
|
|
+}
|
|
+
|
|
+void wake_up_if_idle(int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+
|
|
+ rcu_read_lock();
|
|
+
|
|
+ if (!is_idle_task(rcu_dereference(rq->curr)))
|
|
+ goto out;
|
|
+
|
|
+ if (set_nr_if_polling(rq->idle)) {
|
|
+ trace_sched_wake_idle_without_ipi(cpu);
|
|
+ } else {
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ if (is_idle_task(rq->curr))
|
|
+ smp_send_reschedule(cpu);
|
|
+ /* Else CPU is not idle, do nothing here */
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+ }
|
|
+
|
|
+out:
|
|
+ rcu_read_unlock();
|
|
+}
|
|
+
|
|
+bool cpus_share_cache(int this_cpu, int that_cpu)
|
|
+{
|
|
+ return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
|
|
+}
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+/*
|
|
+ * Topology list, bottom-up.
|
|
+ */
|
|
+static struct sched_domain_topology_level default_topology[] = {
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
|
|
+#endif
|
|
+#ifdef CONFIG_SCHED_MC
|
|
+ { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
|
|
+#endif
|
|
+ { cpu_cpu_mask, SD_INIT_NAME(DIE) },
|
|
+ { NULL, },
|
|
+};
|
|
+
|
|
+static struct sched_domain_topology_level *sched_domain_topology =
|
|
+ default_topology;
|
|
+
|
|
+#define for_each_sd_topology(tl) \
|
|
+ for (tl = sched_domain_topology; tl->mask; tl++)
|
|
+
|
|
+void set_sched_topology(struct sched_domain_topology_level *tl)
|
|
+{
|
|
+ if (WARN_ON_ONCE(sched_smp_initialized))
|
|
+ return;
|
|
+
|
|
+ sched_domain_topology = tl;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * Initializers for schedule domains
|
|
+ * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
|
|
+ */
|
|
+
|
|
+int sched_domain_level_max;
|
|
+
|
|
+/*
|
|
+ * Partition sched domains as specified by the 'ndoms_new'
|
|
+ * cpumasks in the array doms_new[] of cpumasks. This compares
|
|
+ * doms_new[] to the current sched domain partitioning, doms_cur[].
|
|
+ * It destroys each deleted domain and builds each new domain.
|
|
+ *
|
|
+ * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
|
|
+ * The masks don't intersect (don't overlap.) We should setup one
|
|
+ * sched domain for each mask. CPUs not in any of the cpumasks will
|
|
+ * not be load balanced. If the same cpumask appears both in the
|
|
+ * current 'doms_cur' domains and in the new 'doms_new', we can leave
|
|
+ * it as it is.
|
|
+ *
|
|
+ * The passed in 'doms_new' should be allocated using
|
|
+ * alloc_sched_domains. This routine takes ownership of it and will
|
|
+ * free_sched_domains it when done with it. If the caller failed the
|
|
+ * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
|
|
+ * and partition_sched_domains() will fallback to the single partition
|
|
+ * 'fallback_doms', it also forces the domains to be rebuilt.
|
|
+ *
|
|
+ * If doms_new == NULL it will be replaced with cpu_online_mask.
|
|
+ * ndoms_new == 0 is a special case for destroying existing domains,
|
|
+ * and it will not create the default domain.
|
|
+ *
|
|
+ * Call with hotplug lock held
|
|
+ */
|
|
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
|
|
+ struct sched_domain_attr *dattr_new)
|
|
+{
|
|
+ /**
|
|
+ * PDS doesn't depend on sched domains, but just keep this api
|
|
+ */
|
|
+}
|
|
+
|
|
+/*
|
|
+ * used to mark begin/end of suspend/resume:
|
|
+ */
|
|
+static int num_cpus_frozen;
|
|
+
|
|
+#ifdef CONFIG_NUMA
|
|
+int __read_mostly node_reclaim_distance = RECLAIM_DISTANCE;
|
|
+
|
|
+/*
|
|
+ * sched_numa_find_closest() - given the NUMA topology, find the cpu
|
|
+ * closest to @cpu from @cpumask.
|
|
+ * cpumask: cpumask to find a cpu from
|
|
+ * cpu: cpu to be close to
|
|
+ *
|
|
+ * returns: cpu, or nr_cpu_ids when nothing found.
|
|
+ */
|
|
+int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
|
|
+{
|
|
+ return best_mask_cpu(cpu, cpus);
|
|
+}
|
|
+#endif /* CONFIG_NUMA */
|
|
+
|
|
+/*
|
|
+ * Update cpusets according to cpu_active mask. If cpusets are
|
|
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
|
|
+ * around partition_sched_domains().
|
|
+ *
|
|
+ * If we come here as part of a suspend/resume, don't touch cpusets because we
|
|
+ * want to restore it back to its original state upon resume anyway.
|
|
+ */
|
|
+static void cpuset_cpu_active(void)
|
|
+{
|
|
+ if (cpuhp_tasks_frozen) {
|
|
+ /*
|
|
+ * num_cpus_frozen tracks how many CPUs are involved in suspend
|
|
+ * resume sequence. As long as this is not the last online
|
|
+ * operation in the resume sequence, just build a single sched
|
|
+ * domain, ignoring cpusets.
|
|
+ */
|
|
+ partition_sched_domains(1, NULL, NULL);
|
|
+ if (--num_cpus_frozen)
|
|
+ return;
|
|
+ /*
|
|
+ * This is the last CPU online operation. So fall through and
|
|
+ * restore the original sched domains by considering the
|
|
+ * cpuset configurations.
|
|
+ */
|
|
+ cpuset_force_rebuild();
|
|
+ }
|
|
+
|
|
+ cpuset_update_active_cpus();
|
|
+}
|
|
+
|
|
+static int cpuset_cpu_inactive(unsigned int cpu)
|
|
+{
|
|
+ if (!cpuhp_tasks_frozen) {
|
|
+ cpuset_update_active_cpus();
|
|
+ } else {
|
|
+ num_cpus_frozen++;
|
|
+ partition_sched_domains(1, NULL, NULL);
|
|
+ }
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+int sched_cpu_activate(unsigned int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ /*
|
|
+ * When going up, increment the number of cores with SMT present.
|
|
+ */
|
|
+ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
|
|
+ static_branch_inc_cpuslocked(&sched_smt_present);
|
|
+#endif
|
|
+ set_cpu_active(cpu, true);
|
|
+
|
|
+ if (sched_smp_initialized)
|
|
+ cpuset_cpu_active();
|
|
+
|
|
+ /*
|
|
+ * Put the rq online, if not already. This happens:
|
|
+ *
|
|
+ * 1) In the early boot process, because we build the real domains
|
|
+ * after all cpus have been brought up.
|
|
+ *
|
|
+ * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
|
|
+ * domains.
|
|
+ */
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ set_rq_online(rq);
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+int sched_cpu_deactivate(unsigned int cpu)
|
|
+{
|
|
+ int ret;
|
|
+
|
|
+ set_cpu_active(cpu, false);
|
|
+ /*
|
|
+ * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
|
|
+ * users of this state to go away such that all new such users will
|
|
+ * observe it.
|
|
+ *
|
|
+ * Do sync before park smpboot threads to take care the rcu boost case.
|
|
+ */
|
|
+ synchronize_rcu();
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ /*
|
|
+ * When going down, decrement the number of cores with SMT present.
|
|
+ */
|
|
+ if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
|
|
+ static_branch_dec_cpuslocked(&sched_smt_present);
|
|
+#endif
|
|
+
|
|
+ if (!sched_smp_initialized)
|
|
+ return 0;
|
|
+
|
|
+ ret = cpuset_cpu_inactive(cpu);
|
|
+ if (ret) {
|
|
+ set_cpu_active(cpu, true);
|
|
+ return ret;
|
|
+ }
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static void sched_rq_cpu_starting(unsigned int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+
|
|
+ rq->calc_load_update = calc_load_update;
|
|
+}
|
|
+
|
|
+int sched_cpu_starting(unsigned int cpu)
|
|
+{
|
|
+ sched_rq_cpu_starting(cpu);
|
|
+ sched_tick_start(cpu);
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_HOTPLUG_CPU
|
|
+int sched_cpu_dying(unsigned int cpu)
|
|
+{
|
|
+ struct rq *rq = cpu_rq(cpu);
|
|
+ unsigned long flags;
|
|
+
|
|
+ sched_tick_stop(cpu);
|
|
+ raw_spin_lock_irqsave(&rq->lock, flags);
|
|
+ set_rq_offline(rq);
|
|
+ migrate_tasks(rq);
|
|
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
|
|
+
|
|
+ hrtick_clear(rq);
|
|
+ return 0;
|
|
+}
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+static void sched_init_topology_cpumask_early(void)
|
|
+{
|
|
+ int cpu, level;
|
|
+ cpumask_t *tmp;
|
|
+
|
|
+ for_each_possible_cpu(cpu) {
|
|
+ for (level = 0; level < NR_CPU_AFFINITY_CHK_LEVEL; level++) {
|
|
+ tmp = &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[level]);
|
|
+ cpumask_copy(tmp, cpu_possible_mask);
|
|
+ cpumask_clear_cpu(cpu, tmp);
|
|
+ }
|
|
+ per_cpu(sched_cpu_llc_start_mask, cpu) =
|
|
+ &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[0]);
|
|
+ per_cpu(sched_cpu_affinity_chk_end_masks, cpu) =
|
|
+ &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[1]);
|
|
+ }
|
|
+}
|
|
+
|
|
+static void sched_init_topology_cpumask(void)
|
|
+{
|
|
+ int cpu;
|
|
+ cpumask_t *chk;
|
|
+
|
|
+ for_each_online_cpu(cpu) {
|
|
+ chk = &(per_cpu(sched_cpu_affinity_chk_masks, cpu)[0]);
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ cpumask_setall(chk);
|
|
+ cpumask_clear_cpu(cpu, chk);
|
|
+ if (cpumask_and(chk, chk, topology_sibling_cpumask(cpu))) {
|
|
+ per_cpu(sched_sibling_cpu, cpu) = cpumask_first(chk);
|
|
+ printk(KERN_INFO "pds: cpu #%d affinity check mask - smt 0x%08lx",
|
|
+ cpu, (chk++)->bits[0]);
|
|
+ }
|
|
+#endif
|
|
+#ifdef CONFIG_SCHED_MC
|
|
+ cpumask_setall(chk);
|
|
+ cpumask_clear_cpu(cpu, chk);
|
|
+ if (cpumask_and(chk, chk, cpu_coregroup_mask(cpu))) {
|
|
+ per_cpu(sched_cpu_llc_start_mask, cpu) = chk;
|
|
+ printk(KERN_INFO "pds: cpu #%d affinity check mask - coregroup 0x%08lx",
|
|
+ cpu, (chk++)->bits[0]);
|
|
+ }
|
|
+ cpumask_complement(chk, cpu_coregroup_mask(cpu));
|
|
+
|
|
+ /**
|
|
+ * Set up sd_llc_id per CPU
|
|
+ */
|
|
+ per_cpu(sd_llc_id, cpu) =
|
|
+ cpumask_first(cpu_coregroup_mask(cpu));
|
|
+#else
|
|
+ per_cpu(sd_llc_id, cpu) =
|
|
+ cpumask_first(topology_core_cpumask(cpu));
|
|
+
|
|
+ per_cpu(sched_cpu_llc_start_mask, cpu) = chk;
|
|
+
|
|
+ cpumask_setall(chk);
|
|
+ cpumask_clear_cpu(cpu, chk);
|
|
+#endif /* NOT CONFIG_SCHED_MC */
|
|
+ if (cpumask_and(chk, chk, topology_core_cpumask(cpu)))
|
|
+ printk(KERN_INFO "pds: cpu #%d affinity check mask - core 0x%08lx",
|
|
+ cpu, (chk++)->bits[0]);
|
|
+ cpumask_complement(chk, topology_core_cpumask(cpu));
|
|
+
|
|
+ if (cpumask_and(chk, chk, cpu_online_mask))
|
|
+ printk(KERN_INFO "pds: cpu #%d affinity check mask - others 0x%08lx",
|
|
+ cpu, (chk++)->bits[0]);
|
|
+
|
|
+ per_cpu(sched_cpu_affinity_chk_end_masks, cpu) = chk;
|
|
+ }
|
|
+}
|
|
+#endif
|
|
+
|
|
+void __init sched_init_smp(void)
|
|
+{
|
|
+ /* Move init over to a non-isolated CPU */
|
|
+ if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
|
|
+ BUG();
|
|
+
|
|
+ cpumask_copy(&sched_rq_queued_masks[SCHED_RQ_EMPTY], cpu_online_mask);
|
|
+
|
|
+ sched_init_topology_cpumask();
|
|
+
|
|
+ sched_smp_initialized = true;
|
|
+}
|
|
+#else
|
|
+void __init sched_init_smp(void)
|
|
+{
|
|
+}
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+int in_sched_functions(unsigned long addr)
|
|
+{
|
|
+ return in_lock_functions(addr) ||
|
|
+ (addr >= (unsigned long)__sched_text_start
|
|
+ && addr < (unsigned long)__sched_text_end);
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_CGROUP_SCHED
|
|
+/* task group related information */
|
|
+struct task_group {
|
|
+ struct cgroup_subsys_state css;
|
|
+
|
|
+ struct rcu_head rcu;
|
|
+ struct list_head list;
|
|
+
|
|
+ struct task_group *parent;
|
|
+ struct list_head siblings;
|
|
+ struct list_head children;
|
|
+};
|
|
+
|
|
+/*
|
|
+ * Default task group.
|
|
+ * Every task in system belongs to this group at bootup.
|
|
+ */
|
|
+struct task_group root_task_group;
|
|
+LIST_HEAD(task_groups);
|
|
+
|
|
+/* Cacheline aligned slab cache for task_group */
|
|
+static struct kmem_cache *task_group_cache __read_mostly;
|
|
+#endif /* CONFIG_CGROUP_SCHED */
|
|
+
|
|
+void __init sched_init(void)
|
|
+{
|
|
+ int i;
|
|
+ struct rq *rq;
|
|
+
|
|
+ print_scheduler_version();
|
|
+
|
|
+ wait_bit_init();
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ for (i = 0; i < NR_SCHED_RQ_QUEUED_LEVEL; i++)
|
|
+ cpumask_clear(&sched_rq_queued_masks[i]);
|
|
+ cpumask_setall(&sched_rq_queued_masks[SCHED_RQ_EMPTY]);
|
|
+ set_bit(SCHED_RQ_EMPTY, sched_rq_queued_masks_bitmap);
|
|
+
|
|
+ cpumask_setall(&sched_rq_pending_masks[SCHED_RQ_EMPTY]);
|
|
+ set_bit(SCHED_RQ_EMPTY, sched_rq_pending_masks_bitmap);
|
|
+#else
|
|
+ uprq = &per_cpu(runqueues, 0);
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_CGROUP_SCHED
|
|
+ task_group_cache = KMEM_CACHE(task_group, 0);
|
|
+
|
|
+ list_add(&root_task_group.list, &task_groups);
|
|
+ INIT_LIST_HEAD(&root_task_group.children);
|
|
+ INIT_LIST_HEAD(&root_task_group.siblings);
|
|
+#endif /* CONFIG_CGROUP_SCHED */
|
|
+ for_each_possible_cpu(i) {
|
|
+ rq = cpu_rq(i);
|
|
+ FULL_INIT_SKIPLIST_NODE(&rq->sl_header);
|
|
+ raw_spin_lock_init(&rq->lock);
|
|
+ rq->dither = 0;
|
|
+ rq->nr_running = rq->nr_uninterruptible = 0;
|
|
+ rq->calc_load_active = 0;
|
|
+ rq->calc_load_update = jiffies + LOAD_FREQ;
|
|
+#ifdef CONFIG_SMP
|
|
+ rq->online = false;
|
|
+ rq->cpu = i;
|
|
+
|
|
+ rq->queued_level = SCHED_RQ_EMPTY;
|
|
+ rq->pending_level = SCHED_RQ_EMPTY;
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ per_cpu(sched_sibling_cpu, i) = i;
|
|
+ rq->active_balance = 0;
|
|
+#endif
|
|
+#endif
|
|
+ rq->nr_switches = 0;
|
|
+ atomic_set(&rq->nr_iowait, 0);
|
|
+ hrtick_rq_init(rq);
|
|
+ }
|
|
+#ifdef CONFIG_SMP
|
|
+ /* Set rq->online for cpu 0 */
|
|
+ cpu_rq(0)->online = true;
|
|
+#endif
|
|
+
|
|
+ /*
|
|
+ * The boot idle thread does lazy MMU switching as well:
|
|
+ */
|
|
+ mmgrab(&init_mm);
|
|
+ enter_lazy_tlb(&init_mm, current);
|
|
+
|
|
+ /*
|
|
+ * Make us the idle thread. Technically, schedule() should not be
|
|
+ * called from this thread, however somewhere below it might be,
|
|
+ * but because we are the idle thread, we just pick up running again
|
|
+ * when this runqueue becomes "idle".
|
|
+ */
|
|
+ init_idle(current, smp_processor_id());
|
|
+
|
|
+ calc_load_update = jiffies + LOAD_FREQ;
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ idle_thread_set_boot_cpu();
|
|
+
|
|
+ sched_init_topology_cpumask_early();
|
|
+#endif /* SMP */
|
|
+
|
|
+ init_schedstats();
|
|
+
|
|
+ psi_init();
|
|
+}
|
|
+
|
|
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
|
|
+static inline int preempt_count_equals(int preempt_offset)
|
|
+{
|
|
+ int nested = preempt_count() + rcu_preempt_depth();
|
|
+
|
|
+ return (nested == preempt_offset);
|
|
+}
|
|
+
|
|
+void __might_sleep(const char *file, int line, int preempt_offset)
|
|
+{
|
|
+ /*
|
|
+ * Blocking primitives will set (and therefore destroy) current->state,
|
|
+ * since we will exit with TASK_RUNNING make sure we enter with it,
|
|
+ * otherwise we will destroy state.
|
|
+ */
|
|
+ WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
|
|
+ "do not call blocking ops when !TASK_RUNNING; "
|
|
+ "state=%lx set at [<%p>] %pS\n",
|
|
+ current->state,
|
|
+ (void *)current->task_state_change,
|
|
+ (void *)current->task_state_change);
|
|
+
|
|
+ ___might_sleep(file, line, preempt_offset);
|
|
+}
|
|
+EXPORT_SYMBOL(__might_sleep);
|
|
+
|
|
+void ___might_sleep(const char *file, int line, int preempt_offset)
|
|
+{
|
|
+ /* Ratelimiting timestamp: */
|
|
+ static unsigned long prev_jiffy;
|
|
+
|
|
+ unsigned long preempt_disable_ip;
|
|
+
|
|
+ /* WARN_ON_ONCE() by default, no rate limit required: */
|
|
+ rcu_sleep_check();
|
|
+
|
|
+ if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
|
|
+ !is_idle_task(current) && !current->non_block_count) ||
|
|
+ system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
|
|
+ oops_in_progress)
|
|
+ return;
|
|
+ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
|
|
+ return;
|
|
+ prev_jiffy = jiffies;
|
|
+
|
|
+ /* Save this before calling printk(), since that will clobber it: */
|
|
+ preempt_disable_ip = get_preempt_disable_ip(current);
|
|
+
|
|
+ printk(KERN_ERR
|
|
+ "BUG: sleeping function called from invalid context at %s:%d\n",
|
|
+ file, line);
|
|
+ printk(KERN_ERR
|
|
+ "in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
|
|
+ in_atomic(), irqs_disabled(), current->non_block_count,
|
|
+ current->pid, current->comm);
|
|
+
|
|
+ if (task_stack_end_corrupted(current))
|
|
+ printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
|
|
+
|
|
+ debug_show_held_locks(current);
|
|
+ if (irqs_disabled())
|
|
+ print_irqtrace_events(current);
|
|
+#ifdef CONFIG_DEBUG_PREEMPT
|
|
+ if (!preempt_count_equals(preempt_offset)) {
|
|
+ pr_err("Preemption disabled at:");
|
|
+ print_ip_sym(preempt_disable_ip);
|
|
+ pr_cont("\n");
|
|
+ }
|
|
+#endif
|
|
+ dump_stack();
|
|
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
|
|
+}
|
|
+EXPORT_SYMBOL(___might_sleep);
|
|
+
|
|
+void __cant_sleep(const char *file, int line, int preempt_offset)
|
|
+{
|
|
+ static unsigned long prev_jiffy;
|
|
+
|
|
+ if (irqs_disabled())
|
|
+ return;
|
|
+
|
|
+ if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
|
|
+ return;
|
|
+
|
|
+ if (preempt_count() > preempt_offset)
|
|
+ return;
|
|
+
|
|
+ if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
|
|
+ return;
|
|
+ prev_jiffy = jiffies;
|
|
+
|
|
+ printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
|
|
+ printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
|
|
+ in_atomic(), irqs_disabled(),
|
|
+ current->pid, current->comm);
|
|
+
|
|
+ debug_show_held_locks(current);
|
|
+ dump_stack();
|
|
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
|
|
+}
|
|
+EXPORT_SYMBOL_GPL(__cant_sleep);
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_MAGIC_SYSRQ
|
|
+void normalize_rt_tasks(void)
|
|
+{
|
|
+ struct task_struct *g, *p;
|
|
+ struct sched_attr attr = {
|
|
+ .sched_policy = SCHED_NORMAL,
|
|
+ };
|
|
+
|
|
+ read_lock(&tasklist_lock);
|
|
+ for_each_process_thread(g, p) {
|
|
+ /*
|
|
+ * Only normalize user tasks:
|
|
+ */
|
|
+ if (p->flags & PF_KTHREAD)
|
|
+ continue;
|
|
+
|
|
+ if (!rt_task(p)) {
|
|
+ /*
|
|
+ * Renice negative nice level userspace
|
|
+ * tasks back to 0:
|
|
+ */
|
|
+ if (task_nice(p) < 0)
|
|
+ set_user_nice(p, 0);
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ __sched_setscheduler(p, &attr, false, false);
|
|
+ }
|
|
+ read_unlock(&tasklist_lock);
|
|
+}
|
|
+#endif /* CONFIG_MAGIC_SYSRQ */
|
|
+
|
|
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
|
|
+/*
|
|
+ * These functions are only useful for the IA64 MCA handling, or kdb.
|
|
+ *
|
|
+ * They can only be called when the whole system has been
|
|
+ * stopped - every CPU needs to be quiescent, and no scheduling
|
|
+ * activity can take place. Using them for anything else would
|
|
+ * be a serious bug, and as a result, they aren't even visible
|
|
+ * under any other configuration.
|
|
+ */
|
|
+
|
|
+/**
|
|
+ * curr_task - return the current task for a given CPU.
|
|
+ * @cpu: the processor in question.
|
|
+ *
|
|
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
|
|
+ *
|
|
+ * Return: The current task for @cpu.
|
|
+ */
|
|
+struct task_struct *curr_task(int cpu)
|
|
+{
|
|
+ return cpu_curr(cpu);
|
|
+}
|
|
+
|
|
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
|
|
+
|
|
+#ifdef CONFIG_IA64
|
|
+/**
|
|
+ * ia64_set_curr_task - set the current task for a given CPU.
|
|
+ * @cpu: the processor in question.
|
|
+ * @p: the task pointer to set.
|
|
+ *
|
|
+ * Description: This function must only be used when non-maskable interrupts
|
|
+ * are serviced on a separate stack. It allows the architecture to switch the
|
|
+ * notion of the current task on a CPU in a non-blocking manner. This function
|
|
+ * must be called with all CPU's synchronised, and interrupts disabled, the
|
|
+ * and caller must save the original value of the current task (see
|
|
+ * curr_task() above) and restore that value before reenabling interrupts and
|
|
+ * re-starting the system.
|
|
+ *
|
|
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
|
|
+ */
|
|
+void ia64_set_curr_task(int cpu, struct task_struct *p)
|
|
+{
|
|
+ cpu_curr(cpu) = p;
|
|
+}
|
|
+
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SCHED_DEBUG
|
|
+void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
|
|
+ struct seq_file *m)
|
|
+{}
|
|
+
|
|
+void proc_sched_set_task(struct task_struct *p)
|
|
+{}
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_CGROUP_SCHED
|
|
+static void sched_free_group(struct task_group *tg)
|
|
+{
|
|
+ kmem_cache_free(task_group_cache, tg);
|
|
+}
|
|
+
|
|
+/* allocate runqueue etc for a new task group */
|
|
+struct task_group *sched_create_group(struct task_group *parent)
|
|
+{
|
|
+ struct task_group *tg;
|
|
+
|
|
+ tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
|
|
+ if (!tg)
|
|
+ return ERR_PTR(-ENOMEM);
|
|
+
|
|
+ return tg;
|
|
+}
|
|
+
|
|
+void sched_online_group(struct task_group *tg, struct task_group *parent)
|
|
+{
|
|
+}
|
|
+
|
|
+/* rcu callback to free various structures associated with a task group */
|
|
+static void sched_free_group_rcu(struct rcu_head *rhp)
|
|
+{
|
|
+ /* Now it should be safe to free those cfs_rqs */
|
|
+ sched_free_group(container_of(rhp, struct task_group, rcu));
|
|
+}
|
|
+
|
|
+void sched_destroy_group(struct task_group *tg)
|
|
+{
|
|
+ /* Wait for possible concurrent references to cfs_rqs complete */
|
|
+ call_rcu(&tg->rcu, sched_free_group_rcu);
|
|
+}
|
|
+
|
|
+void sched_offline_group(struct task_group *tg)
|
|
+{
|
|
+}
|
|
+
|
|
+static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
|
|
+{
|
|
+ return css ? container_of(css, struct task_group, css) : NULL;
|
|
+}
|
|
+
|
|
+static struct cgroup_subsys_state *
|
|
+cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
|
|
+{
|
|
+ struct task_group *parent = css_tg(parent_css);
|
|
+ struct task_group *tg;
|
|
+
|
|
+ if (!parent) {
|
|
+ /* This is early initialization for the top cgroup */
|
|
+ return &root_task_group.css;
|
|
+ }
|
|
+
|
|
+ tg = sched_create_group(parent);
|
|
+ if (IS_ERR(tg))
|
|
+ return ERR_PTR(-ENOMEM);
|
|
+ return &tg->css;
|
|
+}
|
|
+
|
|
+/* Expose task group only after completing cgroup initialization */
|
|
+static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
|
|
+{
|
|
+ struct task_group *tg = css_tg(css);
|
|
+ struct task_group *parent = css_tg(css->parent);
|
|
+
|
|
+ if (parent)
|
|
+ sched_online_group(tg, parent);
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
|
|
+{
|
|
+ struct task_group *tg = css_tg(css);
|
|
+
|
|
+ sched_offline_group(tg);
|
|
+}
|
|
+
|
|
+static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
|
|
+{
|
|
+ struct task_group *tg = css_tg(css);
|
|
+
|
|
+ /*
|
|
+ * Relies on the RCU grace period between css_released() and this.
|
|
+ */
|
|
+ sched_free_group(tg);
|
|
+}
|
|
+
|
|
+static void cpu_cgroup_fork(struct task_struct *task)
|
|
+{
|
|
+}
|
|
+
|
|
+static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+static void cpu_cgroup_attach(struct cgroup_taskset *tset)
|
|
+{
|
|
+}
|
|
+
|
|
+static struct cftype cpu_legacy_files[] = {
|
|
+ { } /* Terminate */
|
|
+};
|
|
+
|
|
+static struct cftype cpu_files[] = {
|
|
+ { } /* terminate */
|
|
+};
|
|
+
|
|
+static int cpu_extra_stat_show(struct seq_file *sf,
|
|
+ struct cgroup_subsys_state *css)
|
|
+{
|
|
+ return 0;
|
|
+}
|
|
+
|
|
+struct cgroup_subsys cpu_cgrp_subsys = {
|
|
+ .css_alloc = cpu_cgroup_css_alloc,
|
|
+ .css_online = cpu_cgroup_css_online,
|
|
+ .css_released = cpu_cgroup_css_released,
|
|
+ .css_free = cpu_cgroup_css_free,
|
|
+ .css_extra_stat_show = cpu_extra_stat_show,
|
|
+ .fork = cpu_cgroup_fork,
|
|
+ .can_attach = cpu_cgroup_can_attach,
|
|
+ .attach = cpu_cgroup_attach,
|
|
+ .legacy_cftypes = cpu_files,
|
|
+ .legacy_cftypes = cpu_legacy_files,
|
|
+ .dfl_cftypes = cpu_files,
|
|
+ .early_init = true,
|
|
+ .threaded = true,
|
|
+};
|
|
+#endif /* CONFIG_CGROUP_SCHED */
|
|
+
|
|
+#undef CREATE_TRACE_POINTS
|
|
diff --git a/kernel/sched/pds_sched.h b/kernel/sched/pds_sched.h
|
|
new file mode 100644
|
|
index 000000000000..b3926a8425b2
|
|
--- /dev/null
|
|
+++ b/kernel/sched/pds_sched.h
|
|
@@ -0,0 +1,474 @@
|
|
+#ifndef PDS_SCHED_H
|
|
+#define PDS_SCHED_H
|
|
+
|
|
+#include <linux/sched.h>
|
|
+
|
|
+#include <linux/sched/clock.h>
|
|
+#include <linux/sched/cpufreq.h>
|
|
+#include <linux/sched/cputime.h>
|
|
+#include <linux/sched/debug.h>
|
|
+#include <linux/sched/init.h>
|
|
+#include <linux/sched/isolation.h>
|
|
+#include <linux/sched/loadavg.h>
|
|
+#include <linux/sched/mm.h>
|
|
+#include <linux/sched/nohz.h>
|
|
+#include <linux/sched/signal.h>
|
|
+#include <linux/sched/stat.h>
|
|
+#include <linux/sched/sysctl.h>
|
|
+#include <linux/sched/task.h>
|
|
+#include <linux/sched/topology.h>
|
|
+#include <linux/sched/wake_q.h>
|
|
+
|
|
+#include <uapi/linux/sched/types.h>
|
|
+
|
|
+#include <linux/cgroup.h>
|
|
+#include <linux/cpufreq.h>
|
|
+#include <linux/cpuidle.h>
|
|
+#include <linux/cpuset.h>
|
|
+#include <linux/ctype.h>
|
|
+#include <linux/kthread.h>
|
|
+#include <linux/livepatch.h>
|
|
+#include <linux/membarrier.h>
|
|
+#include <linux/proc_fs.h>
|
|
+#include <linux/psi.h>
|
|
+#include <linux/slab.h>
|
|
+#include <linux/stop_machine.h>
|
|
+#include <linux/suspend.h>
|
|
+#include <linux/swait.h>
|
|
+#include <linux/syscalls.h>
|
|
+#include <linux/tsacct_kern.h>
|
|
+
|
|
+#include <asm/tlb.h>
|
|
+
|
|
+#ifdef CONFIG_PARAVIRT
|
|
+# include <asm/paravirt.h>
|
|
+#endif
|
|
+
|
|
+#include "cpupri.h"
|
|
+
|
|
+/* task_struct::on_rq states: */
|
|
+#define TASK_ON_RQ_QUEUED 1
|
|
+#define TASK_ON_RQ_MIGRATING 2
|
|
+
|
|
+static inline int task_on_rq_queued(struct task_struct *p)
|
|
+{
|
|
+ return p->on_rq == TASK_ON_RQ_QUEUED;
|
|
+}
|
|
+
|
|
+static inline int task_on_rq_migrating(struct task_struct *p)
|
|
+{
|
|
+ return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * This is the main, per-CPU runqueue data structure.
|
|
+ * This data should only be modified by the local cpu.
|
|
+ */
|
|
+struct rq {
|
|
+ /* runqueue lock: */
|
|
+ raw_spinlock_t lock;
|
|
+
|
|
+ struct task_struct *curr, *idle, *stop;
|
|
+ struct mm_struct *prev_mm;
|
|
+
|
|
+ struct skiplist_node sl_header;
|
|
+
|
|
+ /* switch count */
|
|
+ u64 nr_switches;
|
|
+
|
|
+ atomic_t nr_iowait;
|
|
+
|
|
+#ifdef CONFIG_MEMBARRIER
|
|
+ int membarrier_state;
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SMP
|
|
+ int cpu; /* cpu of this runqueue */
|
|
+ bool online;
|
|
+
|
|
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
|
|
+ struct sched_avg avg_irq;
|
|
+#endif
|
|
+
|
|
+ unsigned long queued_level;
|
|
+ unsigned long pending_level;
|
|
+
|
|
+#ifdef CONFIG_SCHED_SMT
|
|
+ int active_balance;
|
|
+ struct cpu_stop_work active_balance_work;
|
|
+#endif
|
|
+#endif /* CONFIG_SMP */
|
|
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
+ u64 prev_irq_time;
|
|
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
+#ifdef CONFIG_PARAVIRT
|
|
+ u64 prev_steal_time;
|
|
+#endif /* CONFIG_PARAVIRT */
|
|
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
|
|
+ u64 prev_steal_time_rq;
|
|
+#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */
|
|
+
|
|
+ /* calc_load related fields */
|
|
+ unsigned long calc_load_update;
|
|
+ long calc_load_active;
|
|
+
|
|
+ u64 clock, last_tick;
|
|
+ u64 clock_task;
|
|
+ int dither;
|
|
+
|
|
+ unsigned long nr_running;
|
|
+ unsigned long nr_uninterruptible;
|
|
+
|
|
+#ifdef CONFIG_SCHED_HRTICK
|
|
+#ifdef CONFIG_SMP
|
|
+ int hrtick_csd_pending;
|
|
+ call_single_data_t hrtick_csd;
|
|
+#endif
|
|
+ struct hrtimer hrtick_timer;
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_SCHEDSTATS
|
|
+
|
|
+ /* latency stats */
|
|
+ struct sched_info rq_sched_info;
|
|
+ unsigned long long rq_cpu_time;
|
|
+ /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
|
|
+
|
|
+ /* sys_sched_yield() stats */
|
|
+ unsigned int yld_count;
|
|
+
|
|
+ /* schedule() stats */
|
|
+ unsigned int sched_switch;
|
|
+ unsigned int sched_count;
|
|
+ unsigned int sched_goidle;
|
|
+
|
|
+ /* try_to_wake_up() stats */
|
|
+ unsigned int ttwu_count;
|
|
+ unsigned int ttwu_local;
|
|
+#endif /* CONFIG_SCHEDSTATS */
|
|
+#ifdef CONFIG_CPU_IDLE
|
|
+ /* Must be inspected within a rcu lock section */
|
|
+ struct cpuidle_state *idle_state;
|
|
+#endif
|
|
+};
|
|
+
|
|
+extern unsigned long calc_load_update;
|
|
+extern atomic_long_t calc_load_tasks;
|
|
+
|
|
+extern void calc_global_load_tick(struct rq *this_rq);
|
|
+extern long calc_load_fold_active(struct rq *this_rq, long adjust);
|
|
+
|
|
+#ifndef CONFIG_SMP
|
|
+extern struct rq *uprq;
|
|
+#define cpu_rq(cpu) (uprq)
|
|
+#define this_rq() (uprq)
|
|
+#define raw_rq() (uprq)
|
|
+#define task_rq(p) (uprq)
|
|
+#define cpu_curr(cpu) ((uprq)->curr)
|
|
+#else /* CONFIG_SMP */
|
|
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
|
|
+#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
|
|
+#define this_rq() this_cpu_ptr(&runqueues)
|
|
+#define raw_rq() raw_cpu_ptr(&runqueues)
|
|
+#define task_rq(p) cpu_rq(task_cpu(p))
|
|
+#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
|
|
+
|
|
+#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
|
|
+void register_sched_domain_sysctl(void);
|
|
+void unregister_sched_domain_sysctl(void);
|
|
+#else
|
|
+static inline void register_sched_domain_sysctl(void)
|
|
+{
|
|
+}
|
|
+static inline void unregister_sched_domain_sysctl(void)
|
|
+{
|
|
+}
|
|
+#endif
|
|
+
|
|
+#endif /* CONFIG_SMP */
|
|
+
|
|
+#ifndef arch_scale_freq_capacity
|
|
+static __always_inline
|
|
+unsigned long arch_scale_freq_capacity(int cpu)
|
|
+{
|
|
+ return SCHED_CAPACITY_SCALE;
|
|
+}
|
|
+#endif
|
|
+
|
|
+static inline u64 __rq_clock_broken(struct rq *rq)
|
|
+{
|
|
+ return READ_ONCE(rq->clock);
|
|
+}
|
|
+
|
|
+static inline u64 rq_clock(struct rq *rq)
|
|
+{
|
|
+ /*
|
|
+ * Relax lockdep_assert_held() checking as in VRQ, call to
|
|
+ * sched_info_xxxx() may not held rq->lock
|
|
+ * lockdep_assert_held(&rq->lock);
|
|
+ */
|
|
+ return rq->clock;
|
|
+}
|
|
+
|
|
+static inline u64 rq_clock_task(struct rq *rq)
|
|
+{
|
|
+ /*
|
|
+ * Relax lockdep_assert_held() checking as in VRQ, call to
|
|
+ * sched_info_xxxx() may not held rq->lock
|
|
+ * lockdep_assert_held(&rq->lock);
|
|
+ */
|
|
+ return rq->clock_task;
|
|
+}
|
|
+
|
|
+/*
|
|
+ * {de,en}queue flags:
|
|
+ *
|
|
+ * DEQUEUE_SLEEP - task is no longer runnable
|
|
+ * ENQUEUE_WAKEUP - task just became runnable
|
|
+ *
|
|
+ */
|
|
+
|
|
+#define DEQUEUE_SLEEP 0x01
|
|
+
|
|
+#define ENQUEUE_WAKEUP 0x01
|
|
+
|
|
+
|
|
+/*
|
|
+ * Below are scheduler API which using in other kernel code
|
|
+ * It use the dummy rq_flags
|
|
+ * ToDo : PDS need to support these APIs for compatibility with mainline
|
|
+ * scheduler code.
|
|
+ */
|
|
+struct rq_flags {
|
|
+ unsigned long flags;
|
|
+};
|
|
+
|
|
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
|
|
+ __acquires(rq->lock);
|
|
+
|
|
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
|
|
+ __acquires(p->pi_lock)
|
|
+ __acquires(rq->lock);
|
|
+
|
|
+static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
|
|
+ __releases(rq->lock)
|
|
+{
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+}
|
|
+
|
|
+static inline void
|
|
+task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
|
|
+ __releases(rq->lock)
|
|
+ __releases(p->pi_lock)
|
|
+{
|
|
+ raw_spin_unlock(&rq->lock);
|
|
+ raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
|
|
+}
|
|
+
|
|
+static inline void
|
|
+rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
|
|
+ __releases(rq->lock)
|
|
+{
|
|
+ raw_spin_unlock_irq(&rq->lock);
|
|
+}
|
|
+
|
|
+static inline struct rq *
|
|
+this_rq_lock_irq(struct rq_flags *rf)
|
|
+ __acquires(rq->lock)
|
|
+{
|
|
+ struct rq *rq;
|
|
+
|
|
+ local_irq_disable();
|
|
+ rq = this_rq();
|
|
+ raw_spin_lock(&rq->lock);
|
|
+
|
|
+ return rq;
|
|
+}
|
|
+
|
|
+static inline bool task_running(struct task_struct *p)
|
|
+{
|
|
+ return p->on_cpu;
|
|
+}
|
|
+
|
|
+extern struct static_key_false sched_schedstats;
|
|
+
|
|
+static inline void sched_ttwu_pending(void) { }
|
|
+
|
|
+#ifdef CONFIG_CPU_IDLE
|
|
+static inline void idle_set_state(struct rq *rq,
|
|
+ struct cpuidle_state *idle_state)
|
|
+{
|
|
+ rq->idle_state = idle_state;
|
|
+}
|
|
+
|
|
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
|
|
+{
|
|
+ WARN_ON(!rcu_read_lock_held());
|
|
+ return rq->idle_state;
|
|
+}
|
|
+#else
|
|
+static inline void idle_set_state(struct rq *rq,
|
|
+ struct cpuidle_state *idle_state)
|
|
+{
|
|
+}
|
|
+
|
|
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
|
|
+{
|
|
+ return NULL;
|
|
+}
|
|
+#endif
|
|
+
|
|
+static inline int cpu_of(const struct rq *rq)
|
|
+{
|
|
+#ifdef CONFIG_SMP
|
|
+ return rq->cpu;
|
|
+#else
|
|
+ return 0;
|
|
+#endif
|
|
+}
|
|
+
|
|
+#include "stats.h"
|
|
+
|
|
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
|
|
+struct irqtime {
|
|
+ u64 total;
|
|
+ u64 tick_delta;
|
|
+ u64 irq_start_time;
|
|
+ struct u64_stats_sync sync;
|
|
+};
|
|
+
|
|
+DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
|
|
+
|
|
+/*
|
|
+ * Returns the irqtime minus the softirq time computed by ksoftirqd.
|
|
+ * Otherwise ksoftirqd's sum_exec_runtime is substracted its own runtime
|
|
+ * and never move forward.
|
|
+ */
|
|
+static inline u64 irq_time_read(int cpu)
|
|
+{
|
|
+ struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
|
|
+ unsigned int seq;
|
|
+ u64 total;
|
|
+
|
|
+ do {
|
|
+ seq = __u64_stats_fetch_begin(&irqtime->sync);
|
|
+ total = irqtime->total;
|
|
+ } while (__u64_stats_fetch_retry(&irqtime->sync, seq));
|
|
+
|
|
+ return total;
|
|
+}
|
|
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
|
|
+
|
|
+#ifdef CONFIG_CPU_FREQ
|
|
+DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
|
|
+
|
|
+/**
|
|
+ * cpufreq_update_util - Take a note about CPU utilization changes.
|
|
+ * @rq: Runqueue to carry out the update for.
|
|
+ * @flags: Update reason flags.
|
|
+ *
|
|
+ * This function is called by the scheduler on the CPU whose utilization is
|
|
+ * being updated.
|
|
+ *
|
|
+ * It can only be called from RCU-sched read-side critical sections.
|
|
+ *
|
|
+ * The way cpufreq is currently arranged requires it to evaluate the CPU
|
|
+ * performance state (frequency/voltage) on a regular basis to prevent it from
|
|
+ * being stuck in a completely inadequate performance level for too long.
|
|
+ * That is not guaranteed to happen if the updates are only triggered from CFS
|
|
+ * and DL, though, because they may not be coming in if only RT tasks are
|
|
+ * active all the time (or there are RT tasks only).
|
|
+ *
|
|
+ * As a workaround for that issue, this function is called periodically by the
|
|
+ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
|
|
+ * but that really is a band-aid. Going forward it should be replaced with
|
|
+ * solutions targeted more specifically at RT tasks.
|
|
+ */
|
|
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
|
|
+{
|
|
+ struct update_util_data *data;
|
|
+
|
|
+ data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
|
|
+ if (data)
|
|
+ data->func(data, rq_clock(rq), flags);
|
|
+}
|
|
+
|
|
+static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags)
|
|
+{
|
|
+ if (cpu_of(rq) == smp_processor_id())
|
|
+ cpufreq_update_util(rq, flags);
|
|
+}
|
|
+#else
|
|
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
|
|
+static inline void cpufreq_update_this_cpu(struct rq *rq, unsigned int flags) {}
|
|
+#endif /* CONFIG_CPU_FREQ */
|
|
+
|
|
+#ifdef CONFIG_NO_HZ_FULL
|
|
+extern int __init sched_tick_offload_init(void);
|
|
+#else
|
|
+static inline int sched_tick_offload_init(void) { return 0; }
|
|
+#endif
|
|
+
|
|
+#ifdef arch_scale_freq_capacity
|
|
+#ifndef arch_scale_freq_invariant
|
|
+#define arch_scale_freq_invariant() (true)
|
|
+#endif
|
|
+#else /* arch_scale_freq_capacity */
|
|
+#define arch_scale_freq_invariant() (false)
|
|
+#endif
|
|
+
|
|
+extern void schedule_idle(void);
|
|
+
|
|
+/*
|
|
+ * !! For sched_setattr_nocheck() (kernel) only !!
|
|
+ *
|
|
+ * This is actually gross. :(
|
|
+ *
|
|
+ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
|
|
+ * tasks, but still be able to sleep. We need this on platforms that cannot
|
|
+ * atomically change clock frequency. Remove once fast switching will be
|
|
+ * available on such platforms.
|
|
+ *
|
|
+ * SUGOV stands for SchedUtil GOVernor.
|
|
+ */
|
|
+#define SCHED_FLAG_SUGOV 0x10000000
|
|
+
|
|
+#ifdef CONFIG_MEMBARRIER
|
|
+/*
|
|
+ * The scheduler provides memory barriers required by membarrier between:
|
|
+ * - prior user-space memory accesses and store to rq->membarrier_state,
|
|
+ * - store to rq->membarrier_state and following user-space memory accesses.
|
|
+ * In the same way it provides those guarantees around store to rq->curr.
|
|
+ */
|
|
+static inline void membarrier_switch_mm(struct rq *rq,
|
|
+ struct mm_struct *prev_mm,
|
|
+ struct mm_struct *next_mm)
|
|
+{
|
|
+ int membarrier_state;
|
|
+
|
|
+ if (prev_mm == next_mm)
|
|
+ return;
|
|
+
|
|
+ membarrier_state = atomic_read(&next_mm->membarrier_state);
|
|
+ if (READ_ONCE(rq->membarrier_state) == membarrier_state)
|
|
+ return;
|
|
+
|
|
+ WRITE_ONCE(rq->membarrier_state, membarrier_state);
|
|
+}
|
|
+#else
|
|
+static inline void membarrier_switch_mm(struct rq *rq,
|
|
+ struct mm_struct *prev_mm,
|
|
+ struct mm_struct *next_mm)
|
|
+{
|
|
+}
|
|
+#endif
|
|
+
|
|
+#ifdef CONFIG_NUMA
|
|
+extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
|
|
+#else
|
|
+static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
|
|
+{
|
|
+ return nr_cpu_ids;
|
|
+}
|
|
+#endif
|
|
+#endif /* PDS_SCHED_H */
|
|
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
|
|
index a96db50d40e0..d3d12baa9036 100644
|
|
--- a/kernel/sched/pelt.c
|
|
+++ b/kernel/sched/pelt.c
|
|
@@ -236,6 +236,7 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runna
|
|
WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
|
|
}
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
/*
|
|
* sched_entity:
|
|
*
|
|
@@ -352,6 +353,7 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
|
|
|
|
return 0;
|
|
}
|
|
+#endif
|
|
|
|
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
|
|
/*
|
|
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
|
|
index afff644da065..26d6b47fc156 100644
|
|
--- a/kernel/sched/pelt.h
|
|
+++ b/kernel/sched/pelt.h
|
|
@@ -1,11 +1,13 @@
|
|
#ifdef CONFIG_SMP
|
|
#include "sched-pelt.h"
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
|
|
int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
|
|
int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
|
|
int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
|
|
int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
|
|
+#endif
|
|
|
|
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
|
|
int update_irq_load_avg(struct rq *rq, u64 running);
|
|
@@ -17,6 +19,7 @@ update_irq_load_avg(struct rq *rq, u64 running)
|
|
}
|
|
#endif
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
/*
|
|
* When a task is dequeued, its estimated utilization should not be update if
|
|
* its util_avg has not been updated at least once.
|
|
@@ -137,9 +140,11 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
|
|
return rq_clock_pelt(rq_of(cfs_rq));
|
|
}
|
|
#endif
|
|
+#endif /* CONFIG_SCHED_PDS */
|
|
|
|
#else
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
static inline int
|
|
update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
|
|
{
|
|
@@ -157,6 +162,7 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
|
|
{
|
|
return 0;
|
|
}
|
|
+#endif
|
|
|
|
static inline int
|
|
update_irq_load_avg(struct rq *rq, u64 running)
|
|
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
|
|
index c8870c5bd7df..4fc9f2ead4d2 100644
|
|
--- a/kernel/sched/sched.h
|
|
+++ b/kernel/sched/sched.h
|
|
@@ -2,6 +2,10 @@
|
|
/*
|
|
* Scheduler internal types and methods:
|
|
*/
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+#include "pds_sched.h"
|
|
+#else
|
|
+
|
|
#include <linux/sched.h>
|
|
|
|
#include <linux/sched/autogroup.h>
|
|
@@ -2496,3 +2500,4 @@ static inline void membarrier_switch_mm(struct rq *rq,
|
|
{
|
|
}
|
|
#endif
|
|
+#endif /* !CONFIG_SCHED_PDS */
|
|
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
|
|
index 750fb3c67eed..45bd43942575 100644
|
|
--- a/kernel/sched/stats.c
|
|
+++ b/kernel/sched/stats.c
|
|
@@ -22,8 +22,10 @@ static int show_schedstat(struct seq_file *seq, void *v)
|
|
} else {
|
|
struct rq *rq;
|
|
#ifdef CONFIG_SMP
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
struct sched_domain *sd;
|
|
int dcount = 0;
|
|
+#endif
|
|
#endif
|
|
cpu = (unsigned long)(v - 2);
|
|
rq = cpu_rq(cpu);
|
|
@@ -40,6 +42,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
|
|
seq_printf(seq, "\n");
|
|
|
|
#ifdef CONFIG_SMP
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
/* domain-specific stats */
|
|
rcu_read_lock();
|
|
for_each_domain(cpu, sd) {
|
|
@@ -68,6 +71,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
|
|
sd->ttwu_move_balance);
|
|
}
|
|
rcu_read_unlock();
|
|
+#endif
|
|
#endif
|
|
}
|
|
return 0;
|
|
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
|
|
index b6f2f35d0bcf..204933ebc95a 100644
|
|
--- a/kernel/sysctl.c
|
|
+++ b/kernel/sysctl.c
|
|
@@ -130,8 +130,12 @@ static int __maybe_unused four = 4;
|
|
static unsigned long zero_ul;
|
|
static unsigned long one_ul = 1;
|
|
static unsigned long long_max = LONG_MAX;
|
|
-static int one_hundred = 100;
|
|
-static int one_thousand = 1000;
|
|
+static int __read_mostly one_hundred = 100;
|
|
+static int __read_mostly one_thousand = 1000;
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+extern int rr_interval;
|
|
+extern int sched_yield_type;
|
|
+#endif
|
|
#ifdef CONFIG_PRINTK
|
|
static int ten_thousand = 10000;
|
|
#endif
|
|
@@ -300,7 +304,7 @@ static struct ctl_table sysctl_base_table[] = {
|
|
{ }
|
|
};
|
|
|
|
-#ifdef CONFIG_SCHED_DEBUG
|
|
+#if defined(CONFIG_SCHED_DEBUG) && !defined(CONFIG_SCHED_PDS)
|
|
static int min_sched_granularity_ns = 100000; /* 100 usecs */
|
|
static int max_sched_granularity_ns = NSEC_PER_SEC; /* 1 second */
|
|
static int min_wakeup_granularity_ns; /* 0 usecs */
|
|
@@ -317,6 +321,7 @@ static int max_extfrag_threshold = 1000;
|
|
#endif
|
|
|
|
static struct ctl_table kern_table[] = {
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
{
|
|
.procname = "sched_child_runs_first",
|
|
.data = &sysctl_sched_child_runs_first,
|
|
@@ -498,6 +503,7 @@ static struct ctl_table kern_table[] = {
|
|
.extra2 = SYSCTL_ONE,
|
|
},
|
|
#endif
|
|
+#endif /* !CONFIG_SCHED_PDS */
|
|
#ifdef CONFIG_PROVE_LOCKING
|
|
{
|
|
.procname = "prove_locking",
|
|
@@ -1070,6 +1076,26 @@ static struct ctl_table kern_table[] = {
|
|
.proc_handler = proc_dointvec,
|
|
},
|
|
#endif
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+ {
|
|
+ .procname = "rr_interval",
|
|
+ .data = &rr_interval,
|
|
+ .maxlen = sizeof (int),
|
|
+ .mode = 0644,
|
|
+ .proc_handler = &proc_dointvec_minmax,
|
|
+ .extra1 = SYSCTL_ONE,
|
|
+ .extra2 = &one_thousand,
|
|
+ },
|
|
+ {
|
|
+ .procname = "yield_type",
|
|
+ .data = &sched_yield_type,
|
|
+ .maxlen = sizeof (int),
|
|
+ .mode = 0644,
|
|
+ .proc_handler = &proc_dointvec_minmax,
|
|
+ .extra1 = SYSCTL_ZERO,
|
|
+ .extra2 = &two,
|
|
+ },
|
|
+#endif
|
|
#if defined(CONFIG_S390) && defined(CONFIG_SMP)
|
|
{
|
|
.procname = "spin_retry",
|
|
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
|
|
index 42d512fcfda2..71af3cd30ccc 100644
|
|
--- a/kernel/time/posix-cpu-timers.c
|
|
+++ b/kernel/time/posix-cpu-timers.c
|
|
@@ -226,7 +226,7 @@ static void task_sample_cputime(struct task_struct *p, u64 *samples)
|
|
u64 stime, utime;
|
|
|
|
task_cputime(p, &utime, &stime);
|
|
- store_samples(samples, stime, utime, p->se.sum_exec_runtime);
|
|
+ store_samples(samples, stime, utime, tsk_seruntime(p));
|
|
}
|
|
|
|
static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
|
|
@@ -796,6 +796,7 @@ static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
|
|
}
|
|
}
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
static inline void check_dl_overrun(struct task_struct *tsk)
|
|
{
|
|
if (tsk->dl.dl_overrun) {
|
|
@@ -803,6 +804,7 @@ static inline void check_dl_overrun(struct task_struct *tsk)
|
|
__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
|
|
}
|
|
}
|
|
+#endif
|
|
|
|
static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
|
|
{
|
|
@@ -830,8 +832,10 @@ static void check_thread_timers(struct task_struct *tsk,
|
|
u64 samples[CPUCLOCK_MAX];
|
|
unsigned long soft;
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
if (dl_task(tsk))
|
|
check_dl_overrun(tsk);
|
|
+#endif
|
|
|
|
if (expiry_cache_is_inactive(pct))
|
|
return;
|
|
@@ -845,7 +849,7 @@ static void check_thread_timers(struct task_struct *tsk,
|
|
soft = task_rlimit(tsk, RLIMIT_RTTIME);
|
|
if (soft != RLIM_INFINITY) {
|
|
/* Task RT timeout is accounted in jiffies. RTTIME is usec */
|
|
- unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
|
|
+ unsigned long rttime = tsk_rttimeout(tsk) * (USEC_PER_SEC / HZ);
|
|
unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
|
|
|
|
/* At the hard limit, send SIGKILL. No further action. */
|
|
@@ -1099,8 +1103,10 @@ static inline bool fastpath_timer_check(struct task_struct *tsk)
|
|
return true;
|
|
}
|
|
|
|
+#ifndef CONFIG_SCHED_PDS
|
|
if (dl_task(tsk) && tsk->dl.dl_overrun)
|
|
return true;
|
|
+#endif
|
|
|
|
return false;
|
|
}
|
|
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
|
|
index 69ee8ef12cee..3eaa2a21caa4 100644
|
|
--- a/kernel/trace/trace_selftest.c
|
|
+++ b/kernel/trace/trace_selftest.c
|
|
@@ -1048,10 +1048,15 @@ static int trace_wakeup_test_thread(void *data)
|
|
{
|
|
/* Make this a -deadline thread */
|
|
static const struct sched_attr attr = {
|
|
+#ifdef CONFIG_SCHED_PDS
|
|
+ /* No deadline on BFS, use RR */
|
|
+ .sched_policy = SCHED_RR,
|
|
+#else
|
|
.sched_policy = SCHED_DEADLINE,
|
|
.sched_runtime = 100000ULL,
|
|
.sched_deadline = 10000000ULL,
|
|
.sched_period = 10000000ULL
|
|
+#endif
|
|
};
|
|
struct wakeup_test_data *x = data;
|
|
|