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Message-ID: <20151103102636.GA30362@gmail.com>
Date: Tue, 3 Nov 2015 11:26:36 +0100
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Mike Galbraith <efault@....de>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] scheduler changes for v4.4
Linus,
Please pull the latest sched-core-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-core-for-linus
# HEAD: e73e85f0593832aa583b252f9a16cf90ed6d30fa sched: Don't scan all-offline ->cpus_allowed twice if !CONFIG_CPUSETS
The main changes in this cycle were:
- sched/fair load tracking fixes and cleanups. (Byungchul Park)
- Make load tracking frequency scale invariant. (Dietmar Eggemann)
- sched/deadline updates. (Juri Lelli)
- stop machine fixes, cleanups and enhancements for bugs triggered by CPU
hotplug stress testing. (Oleg Nesterov)
- scheduler preemption code rework: remove PREEMPT_ACTIVE and related cleanups.
(Peter Zijlstra)
- Rework the sched_info::run_delay code to fix races. (Peter Zijlstra)
- Optimize per entity utilization tracking. (Peter Zijlstra)
- ... misc other fixes, cleanups and smaller updates.
Thanks,
Ingo
------------------>
Byungchul Park (5):
sched/fair: Factor out the {at,de}taching of the per entity load {to,from} the runqueue
sched/fair: Have task_move_group_fair() unconditionally add the entity load to the runqueue
sched/fair: Have task_move_group_fair() also detach entity load from the old runqueue
sched/fair: Fix switched_to_fair()'s per entity load tracking
sched/fair: Unify switched_{from,to}_fair() and task_move_group_fair()
Chuck Ebbert (1):
sched/x86: Fix typo in __switch_to() comments
Dietmar Eggemann (5):
sched/fair: Make load tracking frequency scale-invariant
sched/fair: Make utilization tracking CPU scale-invariant
sched/fair: Name utilization related data and functions consistently
sched/fair: Get rid of scaling utilization by capacity_orig
sched/fair: Defer calling scaling functions
Geliang Tang (1):
sched/core: Drop unlikely behind BUG_ON()
Henrik Austad (1):
sched/core: Make policy-testing consistent
Juergen Gross (1):
sched/core: Make 'sched_domain_topology' declaration static
Juri Lelli (3):
sched/deadline: Unify dl_time_before() usage
sched/deadline, locking/rtmutex: Fix open coded check in rt_mutex_waiter_less()
sched/rt: Make (do_)balance_runtime() return void
Kirill Tkhai (1):
sched/core: Delete PF_EXITING checks from cpu_cgroup_exit() callback
Leo Yan (2):
sched/fair: Polish comments for LOAD_AVG_MAX
sched/fair: Remove unnecessary parameter for group_classify()
Morten Rasmussen (2):
sched/fair: Convert arch_scale_cpu_capacity() from weak function to #define
sched/fair: Initialize task load and utilization before placing task on rq
Oleg Nesterov (7):
cpu/hotplug: Read_lock(tasklist_lock) doesn't need to disable irqs
stop_machine: Ensure that a queued callback will be called before cpu_stop_park()
stop_machine: Introduce __cpu_stop_queue_work() and cpu_stop_queue_two_works()
stop_machine: Change cpu_stop_queue_two_works() to rely on stopper->enabled
stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()
stop_machine: Kill cpu_stop_threads->setup() and cpu_stop_unpark()
sched: Don't scan all-offline ->cpus_allowed twice if !CONFIG_CPUSETS
Peter Zijlstra (20):
sched/fair: Make the entity load aging on attaching tunable
sched/core: Remove unused argument from sched_class::task_move_group
sched/fair: Rename scale() to cap_scale()
sched/fair: Optimize __update_load_avg()
sched/fair: Optimize per entity utilization tracking
sched/core: Simplify INIT_PREEMPT_COUNT
sched/core: Rework TASK_DEAD preemption exception
sched/core: Create preempt_count invariant
sched/core: Add preempt argument to __schedule()
sched/core: Fix trace_sched_switch()
sched/core: Stop setting PREEMPT_ACTIVE
sched/core: Robustify preemption leak checks
sched/core: Simplify preempt_count tests
sched/core, sched/x86: Kill thread_info::saved_preempt_count
sched/core: Kill PREEMPT_ACTIVE
sched/core: More notrace annotations
sched/core: Add preempt_count invariant check
sched/core: Fix task and run queue sched_info::run_delay inconsistencies
sched: Start stopper early
sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop()
Rik van Riel (1):
sched/numa: Limit the amount of virtual memory scanned in task_numa_work()
Srikar Dronamraju (5):
sched/numa: Rename numabalancing_enabled to sched_numa_balancing
sched/numa: Disable sched_numa_balancing on UMA systems
sched/numa: Remove the NUMA sched_feature
sched/numa: Convert sched_numa_balancing to a static_branch
sched/numa: Fix task_tick_fair() from disabling numa_balancing
Vincent Guittot (1):
sched/fair: Fix nohz.next_balance update
xiaofeng.yan (1):
sched/core: Remove a parameter in the migrate_task_rq() function
arch/x86/include/asm/preempt.h | 5 +-
arch/x86/include/asm/thread_info.h | 2 -
arch/x86/kernel/process_32.c | 8 -
arch/x86/kernel/process_64.c | 10 +-
include/asm-generic/preempt.h | 2 +-
include/linux/preempt.h | 20 +-
include/linux/sched.h | 38 ++--
include/linux/sched/deadline.h | 5 +
include/linux/smpboot.h | 4 -
include/linux/stop_machine.h | 2 +
include/trace/events/sched.h | 22 +-
kernel/cpu.c | 10 +-
kernel/exit.c | 4 +-
kernel/locking/rtmutex.c | 3 +-
kernel/sched/core.c | 203 ++++++++++--------
kernel/sched/cpudeadline.c | 5 -
kernel/sched/cpudeadline.h | 1 +
kernel/sched/fair.c | 419 ++++++++++++++++++++-----------------
kernel/sched/features.h | 21 +-
kernel/sched/rt.c | 22 +-
kernel/sched/sched.h | 55 ++---
kernel/smpboot.c | 5 +-
kernel/stop_machine.c | 90 ++++----
kernel/trace/ftrace.c | 2 +-
kernel/trace/trace_sched_switch.c | 3 +-
kernel/trace/trace_sched_wakeup.c | 2 +-
26 files changed, 493 insertions(+), 470 deletions(-)
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index b12f81022a6b..01bcde84d3e4 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -30,12 +30,9 @@ static __always_inline void preempt_count_set(int pc)
/*
* must be macros to avoid header recursion hell
*/
-#define init_task_preempt_count(p) do { \
- task_thread_info(p)->saved_preempt_count = PREEMPT_DISABLED; \
-} while (0)
+#define init_task_preempt_count(p) do { } while (0)
#define init_idle_preempt_count(p, cpu) do { \
- task_thread_info(p)->saved_preempt_count = PREEMPT_ENABLED; \
per_cpu(__preempt_count, (cpu)) = PREEMPT_ENABLED; \
} while (0)
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 8afdc3e44247..809877e9030b 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -57,7 +57,6 @@ struct thread_info {
__u32 flags; /* low level flags */
__u32 status; /* thread synchronous flags */
__u32 cpu; /* current CPU */
- int saved_preempt_count;
mm_segment_t addr_limit;
void __user *sysenter_return;
unsigned int sig_on_uaccess_error:1;
@@ -69,7 +68,6 @@ struct thread_info {
.task = &tsk, \
.flags = 0, \
.cpu = 0, \
- .saved_preempt_count = INIT_PREEMPT_COUNT, \
.addr_limit = KERNEL_DS, \
}
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 737527b40e5b..9f950917528b 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -280,14 +280,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
set_iopl_mask(next->iopl);
/*
- * If it were not for PREEMPT_ACTIVE we could guarantee that the
- * preempt_count of all tasks was equal here and this would not be
- * needed.
- */
- task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count);
- this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count);
-
- /*
* Now maybe handle debug registers and/or IO bitmaps
*/
if (unlikely(task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV ||
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index b35921a670b2..e835d263a33b 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -332,7 +332,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
/*
* Switch FS and GS.
*
- * These are even more complicated than FS and GS: they have
+ * These are even more complicated than DS and ES: they have
* 64-bit bases are that controlled by arch_prctl. Those bases
* only differ from the values in the GDT or LDT if the selector
* is 0.
@@ -401,14 +401,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
*/
this_cpu_write(current_task, next_p);
- /*
- * If it were not for PREEMPT_ACTIVE we could guarantee that the
- * preempt_count of all tasks was equal here and this would not be
- * needed.
- */
- task_thread_info(prev_p)->saved_preempt_count = this_cpu_read(__preempt_count);
- this_cpu_write(__preempt_count, task_thread_info(next_p)->saved_preempt_count);
-
/* Reload esp0 and ss1. This changes current_thread_info(). */
load_sp0(tss, next);
diff --git a/include/asm-generic/preempt.h b/include/asm-generic/preempt.h
index 0bec580a4885..5d8ffa3e6f8c 100644
--- a/include/asm-generic/preempt.h
+++ b/include/asm-generic/preempt.h
@@ -24,7 +24,7 @@ static __always_inline void preempt_count_set(int pc)
* must be macros to avoid header recursion hell
*/
#define init_task_preempt_count(p) do { \
- task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
+ task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
} while (0)
#define init_idle_preempt_count(p, cpu) do { \
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index bea8dd8ff5e0..75e4e30677f1 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -26,7 +26,6 @@
* SOFTIRQ_MASK: 0x0000ff00
* HARDIRQ_MASK: 0x000f0000
* NMI_MASK: 0x00100000
- * PREEMPT_ACTIVE: 0x00200000
* PREEMPT_NEED_RESCHED: 0x80000000
*/
#define PREEMPT_BITS 8
@@ -53,10 +52,6 @@
#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
-#define PREEMPT_ACTIVE_BITS 1
-#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
-#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
-
/* We use the MSB mostly because its available */
#define PREEMPT_NEED_RESCHED 0x80000000
@@ -126,8 +121,7 @@
* Check whether we were atomic before we did preempt_disable():
* (used by the scheduler)
*/
-#define in_atomic_preempt_off() \
- ((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_DISABLE_OFFSET)
+#define in_atomic_preempt_off() (preempt_count() != PREEMPT_DISABLE_OFFSET)
#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
extern void preempt_count_add(int val);
@@ -146,18 +140,6 @@ extern void preempt_count_sub(int val);
#define preempt_count_inc() preempt_count_add(1)
#define preempt_count_dec() preempt_count_sub(1)
-#define preempt_active_enter() \
-do { \
- preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
- barrier(); \
-} while (0)
-
-#define preempt_active_exit() \
-do { \
- barrier(); \
- preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
-} while (0)
-
#ifdef CONFIG_PREEMPT_COUNT
#define preempt_disable() \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b7b9501b41af..23ca455d9582 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -599,26 +599,32 @@ struct task_cputime_atomic {
.sum_exec_runtime = ATOMIC64_INIT(0), \
}
-#ifdef CONFIG_PREEMPT_COUNT
-#define PREEMPT_DISABLED (1 + PREEMPT_ENABLED)
-#else
-#define PREEMPT_DISABLED PREEMPT_ENABLED
-#endif
+#define PREEMPT_DISABLED (PREEMPT_DISABLE_OFFSET + PREEMPT_ENABLED)
+
+/*
+ * Disable preemption until the scheduler is running -- use an unconditional
+ * value so that it also works on !PREEMPT_COUNT kernels.
+ *
+ * Reset by start_kernel()->sched_init()->init_idle()->init_idle_preempt_count().
+ */
+#define INIT_PREEMPT_COUNT PREEMPT_OFFSET
/*
- * Disable preemption until the scheduler is running.
- * Reset by start_kernel()->sched_init()->init_idle().
+ * Initial preempt_count value; reflects the preempt_count schedule invariant
+ * which states that during context switches:
*
- * We include PREEMPT_ACTIVE to avoid cond_resched() from working
- * before the scheduler is active -- see should_resched().
+ * preempt_count() == 2*PREEMPT_DISABLE_OFFSET
+ *
+ * Note: PREEMPT_DISABLE_OFFSET is 0 for !PREEMPT_COUNT kernels.
+ * Note: See finish_task_switch().
*/
-#define INIT_PREEMPT_COUNT (PREEMPT_DISABLED + PREEMPT_ACTIVE)
+#define FORK_PREEMPT_COUNT (2*PREEMPT_DISABLE_OFFSET + PREEMPT_ENABLED)
/**
* struct thread_group_cputimer - thread group interval timer counts
* @cputime_atomic: atomic thread group interval timers.
* @running: non-zero when there are timers running and
- * @cputime receives updates.
+ * @cputime receives updates.
*
* This structure contains the version of task_cputime, above, that is
* used for thread group CPU timer calculations.
@@ -1139,8 +1145,6 @@ struct sched_domain_topology_level {
#endif
};
-extern struct sched_domain_topology_level *sched_domain_topology;
-
extern void set_sched_topology(struct sched_domain_topology_level *tl);
extern void wake_up_if_idle(int cpu);
@@ -1189,10 +1193,10 @@ struct load_weight {
/*
* The load_avg/util_avg accumulates an infinite geometric series.
- * 1) load_avg factors the amount of time that a sched_entity is
- * runnable on a rq into its weight. For cfs_rq, it is the aggregated
- * such weights of all runnable and blocked sched_entities.
- * 2) util_avg factors frequency scaling into the amount of time
+ * 1) load_avg factors frequency scaling into the amount of time that a
+ * sched_entity is runnable on a rq into its weight. For cfs_rq, it is the
+ * aggregated such weights of all runnable and blocked sched_entities.
+ * 2) util_avg factors frequency and cpu scaling into the amount of time
* that a sched_entity is running on a CPU, in the range [0..SCHED_LOAD_SCALE].
* For cfs_rq, it is the aggregated such times of all runnable and
* blocked sched_entities.
diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h
index 9d303b8847df..9089a2ae913d 100644
--- a/include/linux/sched/deadline.h
+++ b/include/linux/sched/deadline.h
@@ -21,4 +21,9 @@ static inline int dl_task(struct task_struct *p)
return dl_prio(p->prio);
}
+static inline bool dl_time_before(u64 a, u64 b)
+{
+ return (s64)(a - b) < 0;
+}
+
#endif /* _SCHED_DEADLINE_H */
diff --git a/include/linux/smpboot.h b/include/linux/smpboot.h
index e6109a6cd8f6..12910cf19869 100644
--- a/include/linux/smpboot.h
+++ b/include/linux/smpboot.h
@@ -24,9 +24,6 @@ struct smpboot_thread_data;
* parked (cpu offline)
* @unpark: Optional unpark function, called when the thread is
* unparked (cpu online)
- * @pre_unpark: Optional unpark function, called before the thread is
- * unparked (cpu online). This is not guaranteed to be
- * called on the target cpu of the thread. Careful!
* @cpumask: Internal state. To update which threads are unparked,
* call smpboot_update_cpumask_percpu_thread().
* @selfparking: Thread is not parked by the park function.
@@ -42,7 +39,6 @@ struct smp_hotplug_thread {
void (*cleanup)(unsigned int cpu, bool online);
void (*park)(unsigned int cpu);
void (*unpark)(unsigned int cpu);
- void (*pre_unpark)(unsigned int cpu);
cpumask_var_t cpumask;
bool selfparking;
const char *thread_comm;
diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h
index 414d924318ce..0adedca24c5b 100644
--- a/include/linux/stop_machine.h
+++ b/include/linux/stop_machine.h
@@ -33,6 +33,8 @@ void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
struct cpu_stop_work *work_buf);
int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
int try_stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
+void stop_machine_park(int cpu);
+void stop_machine_unpark(int cpu);
#else /* CONFIG_SMP */
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 539d6bc3216a..9b90c57517a9 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -104,22 +104,17 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
TP_ARGS(p));
#ifdef CREATE_TRACE_POINTS
-static inline long __trace_sched_switch_state(struct task_struct *p)
+static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p)
{
- long state = p->state;
-
-#ifdef CONFIG_PREEMPT
#ifdef CONFIG_SCHED_DEBUG
BUG_ON(p != current);
#endif /* CONFIG_SCHED_DEBUG */
+
/*
- * For all intents and purposes a preempted task is a running task.
+ * Preemption ignores task state, therefore preempted tasks are always
+ * RUNNING (we will not have dequeued if state != RUNNING).
*/
- if (preempt_count() & PREEMPT_ACTIVE)
- state = TASK_RUNNING | TASK_STATE_MAX;
-#endif /* CONFIG_PREEMPT */
-
- return state;
+ return preempt ? TASK_RUNNING | TASK_STATE_MAX : p->state;
}
#endif /* CREATE_TRACE_POINTS */
@@ -128,10 +123,11 @@ static inline long __trace_sched_switch_state(struct task_struct *p)
*/
TRACE_EVENT(sched_switch,
- TP_PROTO(struct task_struct *prev,
+ TP_PROTO(bool preempt,
+ struct task_struct *prev,
struct task_struct *next),
- TP_ARGS(prev, next),
+ TP_ARGS(preempt, prev, next),
TP_STRUCT__entry(
__array( char, prev_comm, TASK_COMM_LEN )
@@ -147,7 +143,7 @@ TRACE_EVENT(sched_switch,
memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
__entry->prev_pid = prev->pid;
__entry->prev_prio = prev->prio;
- __entry->prev_state = __trace_sched_switch_state(prev);
+ __entry->prev_state = __trace_sched_switch_state(preempt, prev);
memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 82cf9dff4295..c85df2775b73 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -304,8 +304,8 @@ static inline void check_for_tasks(int dead_cpu)
{
struct task_struct *g, *p;
- read_lock_irq(&tasklist_lock);
- do_each_thread(g, p) {
+ read_lock(&tasklist_lock);
+ for_each_process_thread(g, p) {
if (!p->on_rq)
continue;
/*
@@ -320,8 +320,8 @@ static inline void check_for_tasks(int dead_cpu)
pr_warn("Task %s (pid=%d) is on cpu %d (state=%ld, flags=%x)\n",
p->comm, task_pid_nr(p), dead_cpu, p->state, p->flags);
- } while_each_thread(g, p);
- read_unlock_irq(&tasklist_lock);
+ }
+ read_unlock(&tasklist_lock);
}
struct take_cpu_down_param {
@@ -344,7 +344,7 @@ static int take_cpu_down(void *_param)
/* Give up timekeeping duties */
tick_handover_do_timer();
/* Park the stopper thread */
- kthread_park(current);
+ stop_machine_park((long)param->hcpu);
return 0;
}
diff --git a/kernel/exit.c b/kernel/exit.c
index ea95ee1b5ef7..443677c8efe6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -706,10 +706,12 @@ void do_exit(long code)
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
- if (unlikely(in_atomic()))
+ if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
preempt_count());
+ preempt_count_set(PREEMPT_ENABLED);
+ }
/* sync mm's RSS info before statistics gathering */
if (tsk->mm)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 7781d801212f..35e9bfcc6ad9 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -158,7 +158,8 @@ rt_mutex_waiter_less(struct rt_mutex_waiter *left,
* then right waiter has a dl_prio() too.
*/
if (dl_prio(left->prio))
- return (left->task->dl.deadline < right->task->dl.deadline);
+ return dl_time_before(left->task->dl.deadline,
+ right->task->dl.deadline);
return 0;
}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5bd7d60658d3..b4d263db52a6 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -817,7 +817,7 @@ static void set_load_weight(struct task_struct *p)
/*
* SCHED_IDLE tasks get minimal weight:
*/
- if (p->policy == SCHED_IDLE) {
+ if (idle_policy(p->policy)) {
load->weight = scale_load(WEIGHT_IDLEPRIO);
load->inv_weight = WMULT_IDLEPRIO;
return;
@@ -827,17 +827,19 @@ static void set_load_weight(struct task_struct *p)
load->inv_weight = prio_to_wmult[prio];
}
-static void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
+static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
- sched_info_queued(rq, p);
+ if (!(flags & ENQUEUE_RESTORE))
+ sched_info_queued(rq, p);
p->sched_class->enqueue_task(rq, p, flags);
}
-static void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
+static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
{
update_rq_clock(rq);
- sched_info_dequeued(rq, p);
+ if (!(flags & DEQUEUE_SAVE))
+ sched_info_dequeued(rq, p);
p->sched_class->dequeue_task(rq, p, flags);
}
@@ -1178,7 +1180,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
* holding rq->lock.
*/
lockdep_assert_held(&rq->lock);
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
}
if (running)
put_prev_task(rq, p);
@@ -1188,7 +1190,7 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
if (running)
p->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
}
/*
@@ -1292,7 +1294,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
if (task_cpu(p) != new_cpu) {
if (p->sched_class->migrate_task_rq)
- p->sched_class->migrate_task_rq(p, new_cpu);
+ p->sched_class->migrate_task_rq(p);
p->se.nr_migrations++;
perf_event_task_migrate(p);
}
@@ -1333,12 +1335,16 @@ static int migrate_swap_stop(void *data)
struct rq *src_rq, *dst_rq;
int ret = -EAGAIN;
+ if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu))
+ return -EAGAIN;
+
src_rq = cpu_rq(arg->src_cpu);
dst_rq = cpu_rq(arg->dst_cpu);
double_raw_lock(&arg->src_task->pi_lock,
&arg->dst_task->pi_lock);
double_rq_lock(src_rq, dst_rq);
+
if (task_cpu(arg->dst_task) != arg->dst_cpu)
goto unlock;
@@ -1574,13 +1580,15 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
goto out;
}
+ /* No more Mr. Nice Guy. */
switch (state) {
case cpuset:
- /* No more Mr. Nice Guy. */
- cpuset_cpus_allowed_fallback(p);
- state = possible;
- break;
-
+ 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;
@@ -1692,7 +1700,7 @@ ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
#endif /* CONFIG_SCHEDSTATS */
}
-static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
+static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
{
activate_task(rq, p, en_flags);
p->on_rq = TASK_ON_RQ_QUEUED;
@@ -2114,23 +2122,17 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
#endif /* CONFIG_NUMA_BALANCING */
}
+DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
+
#ifdef CONFIG_NUMA_BALANCING
-#ifdef CONFIG_SCHED_DEBUG
+
void set_numabalancing_state(bool enabled)
{
if (enabled)
- sched_feat_set("NUMA");
+ static_branch_enable(&sched_numa_balancing);
else
- sched_feat_set("NO_NUMA");
+ static_branch_disable(&sched_numa_balancing);
}
-#else
-__read_mostly bool numabalancing_enabled;
-
-void set_numabalancing_state(bool enabled)
-{
- numabalancing_enabled = enabled;
-}
-#endif /* CONFIG_SCHED_DEBUG */
#ifdef CONFIG_PROC_SYSCTL
int sysctl_numa_balancing(struct ctl_table *table, int write,
@@ -2138,7 +2140,7 @@ int sysctl_numa_balancing(struct ctl_table *table, int write,
{
struct ctl_table t;
int err;
- int state = numabalancing_enabled;
+ int state = static_branch_likely(&sched_numa_balancing);
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -2349,6 +2351,8 @@ void wake_up_new_task(struct task_struct *p)
struct rq *rq;
raw_spin_lock_irqsave(&p->pi_lock, flags);
+ /* Initialize new task's runnable average */
+ init_entity_runnable_average(&p->se);
#ifdef CONFIG_SMP
/*
* Fork balancing, do it here and not earlier because:
@@ -2358,8 +2362,6 @@ void wake_up_new_task(struct task_struct *p)
set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0));
#endif
- /* Initialize new task's runnable average */
- init_entity_runnable_average(&p->se);
rq = __task_rq_lock(p);
activate_task(rq, p, 0);
p->on_rq = TASK_ON_RQ_QUEUED;
@@ -2476,7 +2478,6 @@ static inline void
prepare_task_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
- trace_sched_switch(prev, next);
sched_info_switch(rq, prev, next);
perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
@@ -2510,6 +2511,22 @@ static struct rq *finish_task_switch(struct task_struct *prev)
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;
/*
@@ -2594,8 +2611,15 @@ asmlinkage __visible void schedule_tail(struct task_struct *prev)
{
struct rq *rq;
- /* finish_task_switch() drops rq->lock and enables preemtion */
- preempt_disable();
+ /*
+ * 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);
balance_callback(rq);
preempt_enable();
@@ -2953,15 +2977,13 @@ static noinline void __schedule_bug(struct task_struct *prev)
static inline void schedule_debug(struct task_struct *prev)
{
#ifdef CONFIG_SCHED_STACK_END_CHECK
- BUG_ON(unlikely(task_stack_end_corrupted(prev)));
+ BUG_ON(task_stack_end_corrupted(prev));
#endif
- /*
- * Test if we are atomic. Since do_exit() needs to call into
- * schedule() atomically, we ignore that path. Otherwise whine
- * if we are scheduling when we should not.
- */
- if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD))
+
+ 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));
@@ -3047,7 +3069,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev)
*
* WARNING: must be called with preemption disabled!
*/
-static void __sched __schedule(void)
+static void __sched notrace __schedule(bool preempt)
{
struct task_struct *prev, *next;
unsigned long *switch_count;
@@ -3059,6 +3081,17 @@ static void __sched __schedule(void)
rcu_note_context_switch();
prev = rq->curr;
+ /*
+ * do_exit() calls schedule() with preemption disabled as an exception;
+ * however we must fix that up, otherwise the next task will see an
+ * inconsistent (higher) preempt count.
+ *
+ * It also avoids the below schedule_debug() test from complaining
+ * about this.
+ */
+ if (unlikely(prev->state == TASK_DEAD))
+ preempt_enable_no_resched_notrace();
+
schedule_debug(prev);
if (sched_feat(HRTICK))
@@ -3076,7 +3109,7 @@ static void __sched __schedule(void)
rq->clock_skip_update <<= 1; /* promote REQ to ACT */
switch_count = &prev->nivcsw;
- if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+ if (!preempt && prev->state) {
if (unlikely(signal_pending_state(prev->state, prev))) {
prev->state = TASK_RUNNING;
} else {
@@ -3112,6 +3145,7 @@ static void __sched __schedule(void)
rq->curr = next;
++*switch_count;
+ trace_sched_switch(preempt, prev, next);
rq = context_switch(rq, prev, next); /* unlocks the rq */
cpu = cpu_of(rq);
} else {
@@ -3141,7 +3175,7 @@ asmlinkage __visible void __sched schedule(void)
sched_submit_work(tsk);
do {
preempt_disable();
- __schedule();
+ __schedule(false);
sched_preempt_enable_no_resched();
} while (need_resched());
}
@@ -3181,9 +3215,9 @@ void __sched schedule_preempt_disabled(void)
static void __sched notrace preempt_schedule_common(void)
{
do {
- preempt_active_enter();
- __schedule();
- preempt_active_exit();
+ preempt_disable_notrace();
+ __schedule(true);
+ preempt_enable_no_resched_notrace();
/*
* Check again in case we missed a preemption opportunity
@@ -3234,24 +3268,17 @@ asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
return;
do {
- /*
- * Use raw __prempt_count() ops that don't call function.
- * We can't call functions before disabling preemption which
- * disarm preemption tracing recursions.
- */
- __preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET);
- barrier();
+ preempt_disable_notrace();
/*
* 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();
+ __schedule(true);
exception_exit(prev_ctx);
- barrier();
- __preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET);
+ preempt_enable_no_resched_notrace();
} while (need_resched());
}
EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
@@ -3274,11 +3301,11 @@ asmlinkage __visible void __sched preempt_schedule_irq(void)
prev_state = exception_enter();
do {
- preempt_active_enter();
+ preempt_disable();
local_irq_enable();
- __schedule();
+ __schedule(true);
local_irq_disable();
- preempt_active_exit();
+ sched_preempt_enable_no_resched();
} while (need_resched());
exception_exit(prev_state);
@@ -3306,7 +3333,7 @@ EXPORT_SYMBOL(default_wake_function);
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
- int oldprio, queued, running, enqueue_flag = 0;
+ int oldprio, queued, running, enqueue_flag = ENQUEUE_RESTORE;
struct rq *rq;
const struct sched_class *prev_class;
@@ -3338,7 +3365,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
queued = task_on_rq_queued(p);
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -3356,7 +3383,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
if (!dl_prio(p->normal_prio) ||
(pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) {
p->dl.dl_boosted = 1;
- enqueue_flag = ENQUEUE_REPLENISH;
+ enqueue_flag |= ENQUEUE_REPLENISH;
} else
p->dl.dl_boosted = 0;
p->sched_class = &dl_sched_class;
@@ -3364,7 +3391,7 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
if (dl_prio(oldprio))
p->dl.dl_boosted = 0;
if (oldprio < prio)
- enqueue_flag = ENQUEUE_HEAD;
+ enqueue_flag |= ENQUEUE_HEAD;
p->sched_class = &rt_sched_class;
} else {
if (dl_prio(oldprio))
@@ -3416,7 +3443,7 @@ void set_user_nice(struct task_struct *p, long nice)
}
queued = task_on_rq_queued(p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
p->static_prio = NICE_TO_PRIO(nice);
set_load_weight(p);
@@ -3425,7 +3452,7 @@ void set_user_nice(struct task_struct *p, long nice)
delta = p->prio - old_prio;
if (queued) {
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
/*
* If the task increased its priority or is running and
* lowered its priority, then reschedule its CPU:
@@ -3746,10 +3773,7 @@ static int __sched_setscheduler(struct task_struct *p,
} else {
reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK);
- if (policy != SCHED_DEADLINE &&
- policy != SCHED_FIFO && policy != SCHED_RR &&
- policy != SCHED_NORMAL && policy != SCHED_BATCH &&
- policy != SCHED_IDLE)
+ if (!valid_policy(policy))
return -EINVAL;
}
@@ -3805,7 +3829,7 @@ static int __sched_setscheduler(struct task_struct *p,
* Treat SCHED_IDLE as nice 20. Only allow a switch to
* SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
*/
- if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
+ if (idle_policy(p->policy) && !idle_policy(policy)) {
if (!can_nice(p, task_nice(p)))
return -EPERM;
}
@@ -3930,7 +3954,7 @@ static int __sched_setscheduler(struct task_struct *p,
queued = task_on_rq_queued(p);
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -3940,11 +3964,15 @@ static int __sched_setscheduler(struct task_struct *p,
if (running)
p->sched_class->set_curr_task(rq);
if (queued) {
+ int enqueue_flags = ENQUEUE_RESTORE;
/*
* We enqueue to tail when the priority of a task is
* increased (user space view).
*/
- enqueue_task(rq, p, oldprio <= p->prio ? ENQUEUE_HEAD : 0);
+ if (oldprio <= p->prio)
+ enqueue_flags |= ENQUEUE_HEAD;
+
+ enqueue_task(rq, p, enqueue_flags);
}
check_class_changed(rq, p, prev_class, oldprio);
@@ -5093,7 +5121,7 @@ void sched_setnuma(struct task_struct *p, int nid)
running = task_current(rq, p);
if (queued)
- dequeue_task(rq, p, 0);
+ dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
@@ -5102,7 +5130,7 @@ void sched_setnuma(struct task_struct *p, int nid)
if (running)
p->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, p, 0);
+ enqueue_task(rq, p, ENQUEUE_RESTORE);
task_rq_unlock(rq, p, &flags);
}
#endif /* CONFIG_NUMA_BALANCING */
@@ -5523,21 +5551,27 @@ static void set_cpu_rq_start_time(void)
static int sched_cpu_active(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
+ int cpu = (long)hcpu;
+
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_STARTING:
set_cpu_rq_start_time();
return NOTIFY_OK;
+
case CPU_ONLINE:
/*
* At this point a starting CPU has marked itself as online via
* set_cpu_online(). But it might not yet have marked itself
* as active, which is essential from here on.
- *
- * Thus, fall-through and help the starting CPU along.
*/
+ set_cpu_active(cpu, true);
+ stop_machine_unpark(cpu);
+ return NOTIFY_OK;
+
case CPU_DOWN_FAILED:
- set_cpu_active((long)hcpu, true);
+ set_cpu_active(cpu, true);
return NOTIFY_OK;
+
default:
return NOTIFY_DONE;
}
@@ -6469,7 +6503,8 @@ static struct sched_domain_topology_level default_topology[] = {
{ NULL, },
};
-struct sched_domain_topology_level *sched_domain_topology = default_topology;
+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++)
@@ -7470,7 +7505,7 @@ void __init sched_init(void)
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
static inline int preempt_count_equals(int preempt_offset)
{
- int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();
+ int nested = preempt_count() + rcu_preempt_depth();
return (nested == preempt_offset);
}
@@ -7717,7 +7752,7 @@ void sched_move_task(struct task_struct *tsk)
queued = task_on_rq_queued(tsk);
if (queued)
- dequeue_task(rq, tsk, 0);
+ dequeue_task(rq, tsk, DEQUEUE_SAVE);
if (unlikely(running))
put_prev_task(rq, tsk);
@@ -7733,7 +7768,7 @@ void sched_move_task(struct task_struct *tsk)
#ifdef CONFIG_FAIR_GROUP_SCHED
if (tsk->sched_class->task_move_group)
- tsk->sched_class->task_move_group(tsk, queued);
+ tsk->sched_class->task_move_group(tsk);
else
#endif
set_task_rq(tsk, task_cpu(tsk));
@@ -7741,7 +7776,7 @@ void sched_move_task(struct task_struct *tsk)
if (unlikely(running))
tsk->sched_class->set_curr_task(rq);
if (queued)
- enqueue_task(rq, tsk, 0);
+ enqueue_task(rq, tsk, ENQUEUE_RESTORE);
task_rq_unlock(rq, tsk, &flags);
}
@@ -8205,14 +8240,6 @@ static void cpu_cgroup_exit(struct cgroup_subsys_state *css,
struct cgroup_subsys_state *old_css,
struct task_struct *task)
{
- /*
- * cgroup_exit() is called in the copy_process() failure path.
- * Ignore this case since the task hasn't ran yet, this avoids
- * trying to poke a half freed task state from generic code.
- */
- if (!(task->flags & PF_EXITING))
- return;
-
sched_move_task(task);
}
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index c6acb07466bb..5a75b08cfd85 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -31,11 +31,6 @@ static inline int right_child(int i)
return (i << 1) + 2;
}
-static inline int dl_time_before(u64 a, u64 b)
-{
- return (s64)(a - b) < 0;
-}
-
static void cpudl_exchange(struct cpudl *cp, int a, int b)
{
int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
diff --git a/kernel/sched/cpudeadline.h b/kernel/sched/cpudeadline.h
index 1a0a6ef2fbe1..fcbdf83fed7e 100644
--- a/kernel/sched/cpudeadline.h
+++ b/kernel/sched/cpudeadline.h
@@ -2,6 +2,7 @@
#define _LINUX_CPUDL_H
#include <linux/sched.h>
+#include <linux/sched/deadline.h>
#define IDX_INVALID -1
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9a5e60fe721a..824aa9f501a3 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -661,11 +661,12 @@ static unsigned long task_h_load(struct task_struct *p);
/*
* We choose a half-life close to 1 scheduling period.
- * Note: The tables below are dependent on this value.
+ * Note: The tables runnable_avg_yN_inv and runnable_avg_yN_sum are
+ * dependent on this value.
*/
#define LOAD_AVG_PERIOD 32
#define LOAD_AVG_MAX 47742 /* maximum possible load avg */
-#define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_MAX_AVG */
+#define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_AVG_MAX */
/* Give new sched_entity start runnable values to heavy its load in infant time */
void init_entity_runnable_average(struct sched_entity *se)
@@ -682,7 +683,7 @@ void init_entity_runnable_average(struct sched_entity *se)
sa->load_avg = scale_load_down(se->load.weight);
sa->load_sum = sa->load_avg * LOAD_AVG_MAX;
sa->util_avg = scale_load_down(SCHED_LOAD_SCALE);
- sa->util_sum = LOAD_AVG_MAX;
+ sa->util_sum = sa->util_avg * LOAD_AVG_MAX;
/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
}
@@ -2069,7 +2070,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
int local = !!(flags & TNF_FAULT_LOCAL);
int priv;
- if (!numabalancing_enabled)
+ if (!static_branch_likely(&sched_numa_balancing))
return;
/* for example, ksmd faulting in a user's mm */
@@ -2157,7 +2158,7 @@ void task_numa_work(struct callback_head *work)
struct vm_area_struct *vma;
unsigned long start, end;
unsigned long nr_pte_updates = 0;
- long pages;
+ long pages, virtpages;
WARN_ON_ONCE(p != container_of(work, struct task_struct, numa_work));
@@ -2203,9 +2204,11 @@ void task_numa_work(struct callback_head *work)
start = mm->numa_scan_offset;
pages = sysctl_numa_balancing_scan_size;
pages <<= 20 - PAGE_SHIFT; /* MB in pages */
+ virtpages = pages * 8; /* Scan up to this much virtual space */
if (!pages)
return;
+
down_read(&mm->mmap_sem);
vma = find_vma(mm, start);
if (!vma) {
@@ -2240,18 +2243,22 @@ void task_numa_work(struct callback_head *work)
start = max(start, vma->vm_start);
end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
end = min(end, vma->vm_end);
- nr_pte_updates += change_prot_numa(vma, start, end);
+ nr_pte_updates = change_prot_numa(vma, start, end);
/*
- * Scan sysctl_numa_balancing_scan_size but ensure that
- * at least one PTE is updated so that unused virtual
- * address space is quickly skipped.
+ * Try to scan sysctl_numa_balancing_size worth of
+ * hpages that have at least one present PTE that
+ * is not already pte-numa. If the VMA contains
+ * areas that are unused or already full of prot_numa
+ * PTEs, scan up to virtpages, to skip through those
+ * areas faster.
*/
if (nr_pte_updates)
pages -= (end - start) >> PAGE_SHIFT;
+ virtpages -= (end - start) >> PAGE_SHIFT;
start = end;
- if (pages <= 0)
+ if (pages <= 0 || virtpages <= 0)
goto out;
cond_resched();
@@ -2515,6 +2522,12 @@ static u32 __compute_runnable_contrib(u64 n)
return contrib + runnable_avg_yN_sum[n];
}
+#if (SCHED_LOAD_SHIFT - SCHED_LOAD_RESOLUTION) != 10 || SCHED_CAPACITY_SHIFT != 10
+#error "load tracking assumes 2^10 as unit"
+#endif
+
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
/*
* We can represent the historical contribution to runnable average as the
* coefficients of a geometric series. To do this we sub-divide our runnable
@@ -2547,10 +2560,10 @@ static __always_inline int
__update_load_avg(u64 now, int cpu, struct sched_avg *sa,
unsigned long weight, int running, struct cfs_rq *cfs_rq)
{
- u64 delta, periods;
+ u64 delta, scaled_delta, periods;
u32 contrib;
- int delta_w, decayed = 0;
- unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu);
+ unsigned int delta_w, scaled_delta_w, decayed = 0;
+ unsigned long scale_freq, scale_cpu;
delta = now - sa->last_update_time;
/*
@@ -2571,6 +2584,9 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
return 0;
sa->last_update_time = now;
+ scale_freq = arch_scale_freq_capacity(NULL, cpu);
+ scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
+
/* delta_w is the amount already accumulated against our next period */
delta_w = sa->period_contrib;
if (delta + delta_w >= 1024) {
@@ -2585,13 +2601,16 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
* period and accrue it.
*/
delta_w = 1024 - delta_w;
+ scaled_delta_w = cap_scale(delta_w, scale_freq);
if (weight) {
- sa->load_sum += weight * delta_w;
- if (cfs_rq)
- cfs_rq->runnable_load_sum += weight * delta_w;
+ sa->load_sum += weight * scaled_delta_w;
+ if (cfs_rq) {
+ cfs_rq->runnable_load_sum +=
+ weight * scaled_delta_w;
+ }
}
if (running)
- sa->util_sum += delta_w * scale_freq >> SCHED_CAPACITY_SHIFT;
+ sa->util_sum += scaled_delta_w * scale_cpu;
delta -= delta_w;
@@ -2608,23 +2627,25 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
/* Efficiently calculate \sum (1..n_period) 1024*y^i */
contrib = __compute_runnable_contrib(periods);
+ contrib = cap_scale(contrib, scale_freq);
if (weight) {
sa->load_sum += weight * contrib;
if (cfs_rq)
cfs_rq->runnable_load_sum += weight * contrib;
}
if (running)
- sa->util_sum += contrib * scale_freq >> SCHED_CAPACITY_SHIFT;
+ sa->util_sum += contrib * scale_cpu;
}
/* Remainder of delta accrued against u_0` */
+ scaled_delta = cap_scale(delta, scale_freq);
if (weight) {
- sa->load_sum += weight * delta;
+ sa->load_sum += weight * scaled_delta;
if (cfs_rq)
- cfs_rq->runnable_load_sum += weight * delta;
+ cfs_rq->runnable_load_sum += weight * scaled_delta;
}
if (running)
- sa->util_sum += delta * scale_freq >> SCHED_CAPACITY_SHIFT;
+ sa->util_sum += scaled_delta * scale_cpu;
sa->period_contrib += delta;
@@ -2634,7 +2655,7 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
cfs_rq->runnable_load_avg =
div_u64(cfs_rq->runnable_load_sum, LOAD_AVG_MAX);
}
- sa->util_avg = (sa->util_sum << SCHED_LOAD_SHIFT) / LOAD_AVG_MAX;
+ sa->util_avg = sa->util_sum / LOAD_AVG_MAX;
}
return decayed;
@@ -2677,8 +2698,7 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
if (atomic_long_read(&cfs_rq->removed_util_avg)) {
long r = atomic_long_xchg(&cfs_rq->removed_util_avg, 0);
sa->util_avg = max_t(long, sa->util_avg - r, 0);
- sa->util_sum = max_t(s32, sa->util_sum -
- ((r * LOAD_AVG_MAX) >> SCHED_LOAD_SHIFT), 0);
+ sa->util_sum = max_t(s32, sa->util_sum - r * LOAD_AVG_MAX, 0);
}
decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
@@ -2696,33 +2716,70 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
static inline void update_load_avg(struct sched_entity *se, int update_tg)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- int cpu = cpu_of(rq_of(cfs_rq));
u64 now = cfs_rq_clock_task(cfs_rq);
+ int cpu = cpu_of(rq_of(cfs_rq));
/*
* Track task load average for carrying it to new CPU after migrated, and
* track group sched_entity load average for task_h_load calc in migration
*/
__update_load_avg(now, cpu, &se->avg,
- se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL);
+ se->on_rq * scale_load_down(se->load.weight),
+ cfs_rq->curr == se, NULL);
if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg)
update_tg_load_avg(cfs_rq, 0);
}
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ if (!sched_feat(ATTACH_AGE_LOAD))
+ goto skip_aging;
+
+ /*
+ * If we got migrated (either between CPUs or between cgroups) we'll
+ * have aged the average right before clearing @last_update_time.
+ */
+ if (se->avg.last_update_time) {
+ __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
+ &se->avg, 0, 0, NULL);
+
+ /*
+ * XXX: we could have just aged the entire load away if we've been
+ * absent from the fair class for too long.
+ */
+ }
+
+skip_aging:
+ se->avg.last_update_time = cfs_rq->avg.last_update_time;
+ cfs_rq->avg.load_avg += se->avg.load_avg;
+ cfs_rq->avg.load_sum += se->avg.load_sum;
+ cfs_rq->avg.util_avg += se->avg.util_avg;
+ cfs_rq->avg.util_sum += se->avg.util_sum;
+}
+
+static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
+ &se->avg, se->on_rq * scale_load_down(se->load.weight),
+ cfs_rq->curr == se, NULL);
+
+ cfs_rq->avg.load_avg = max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0);
+ cfs_rq->avg.load_sum = max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0);
+ cfs_rq->avg.util_avg = max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0);
+ cfs_rq->avg.util_sum = max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0);
+}
+
/* Add the load generated by se into cfs_rq's load average */
static inline void
enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct sched_avg *sa = &se->avg;
u64 now = cfs_rq_clock_task(cfs_rq);
- int migrated = 0, decayed;
+ int migrated, decayed;
- if (sa->last_update_time == 0) {
- sa->last_update_time = now;
- migrated = 1;
- }
- else {
+ migrated = !sa->last_update_time;
+ if (!migrated) {
__update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
se->on_rq * scale_load_down(se->load.weight),
cfs_rq->curr == se, NULL);
@@ -2733,12 +2790,8 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->runnable_load_avg += sa->load_avg;
cfs_rq->runnable_load_sum += sa->load_sum;
- if (migrated) {
- cfs_rq->avg.load_avg += sa->load_avg;
- cfs_rq->avg.load_sum += sa->load_sum;
- cfs_rq->avg.util_avg += sa->util_avg;
- cfs_rq->avg.util_sum += sa->util_sum;
- }
+ if (migrated)
+ attach_entity_load_avg(cfs_rq, se);
if (decayed || migrated)
update_tg_load_avg(cfs_rq, 0);
@@ -2753,7 +2806,7 @@ dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->runnable_load_avg =
max_t(long, cfs_rq->runnable_load_avg - se->avg.load_avg, 0);
cfs_rq->runnable_load_sum =
- max_t(s64, cfs_rq->runnable_load_sum - se->avg.load_sum, 0);
+ max_t(s64, cfs_rq->runnable_load_sum - se->avg.load_sum, 0);
}
/*
@@ -2821,6 +2874,11 @@ static inline void
dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
static inline void remove_entity_load_avg(struct sched_entity *se) {}
+static inline void
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+static inline void
+detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+
static inline int idle_balance(struct rq *rq)
{
return 0;
@@ -4817,32 +4875,39 @@ static int select_idle_sibling(struct task_struct *p, int target)
done:
return target;
}
+
/*
- * get_cpu_usage returns the amount of capacity of a CPU that is used by CFS
+ * cpu_util returns the amount of capacity of a CPU that is used by CFS
* tasks. The unit of the return value must be the one of capacity so we can
- * compare the usage with the capacity of the CPU that is available for CFS
- * task (ie cpu_capacity).
- * cfs.avg.util_avg is the sum of running time of runnable tasks on a
- * CPU. It represents the amount of utilization of a CPU in the range
- * [0..SCHED_LOAD_SCALE]. The usage of a CPU can't be higher than the full
- * capacity of the CPU because it's about the running time on this CPU.
- * Nevertheless, cfs.avg.util_avg can be higher than SCHED_LOAD_SCALE
- * because of unfortunate rounding in util_avg or just
- * after migrating tasks until the average stabilizes with the new running
- * time. So we need to check that the usage stays into the range
- * [0..cpu_capacity_orig] and cap if necessary.
- * Without capping the usage, a group could be seen as overloaded (CPU0 usage
- * at 121% + CPU1 usage at 80%) whereas CPU1 has 20% of available capacity
+ * compare the utilization with the capacity of the CPU that is available for
+ * CFS task (ie cpu_capacity).
+ *
+ * cfs_rq.avg.util_avg is the sum of running time of runnable tasks plus the
+ * recent utilization of currently non-runnable tasks on a CPU. It represents
+ * the amount of utilization of a CPU in the range [0..capacity_orig] where
+ * capacity_orig is the cpu_capacity available at the highest frequency
+ * (arch_scale_freq_capacity()).
+ * The utilization of a CPU converges towards a sum equal to or less than the
+ * current capacity (capacity_curr <= capacity_orig) of the CPU because it is
+ * the running time on this CPU scaled by capacity_curr.
+ *
+ * Nevertheless, cfs_rq.avg.util_avg can be higher than capacity_curr or even
+ * higher than capacity_orig because of unfortunate rounding in
+ * cfs.avg.util_avg or just after migrating tasks and new task wakeups until
+ * the average stabilizes with the new running time. We need to check that the
+ * utilization stays within the range of [0..capacity_orig] and cap it if
+ * necessary. Without utilization capping, a group could be seen as overloaded
+ * (CPU0 utilization at 121% + CPU1 utilization at 80%) whereas CPU1 has 20% of
+ * available capacity. We allow utilization to overshoot capacity_curr (but not
+ * capacity_orig) as it useful for predicting the capacity required after task
+ * migrations (scheduler-driven DVFS).
*/
-static int get_cpu_usage(int cpu)
+static int cpu_util(int cpu)
{
- unsigned long usage = cpu_rq(cpu)->cfs.avg.util_avg;
+ unsigned long util = cpu_rq(cpu)->cfs.avg.util_avg;
unsigned long capacity = capacity_orig_of(cpu);
- if (usage >= SCHED_LOAD_SCALE)
- return capacity;
-
- return (usage * capacity) >> SCHED_LOAD_SHIFT;
+ return (util >= capacity) ? capacity : util;
}
/*
@@ -4945,7 +5010,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
* previous cpu. However, the caller only guarantees p->pi_lock is held; no
* other assumptions, including the state of rq->lock, should be made.
*/
-static void migrate_task_rq_fair(struct task_struct *p, int next_cpu)
+static void migrate_task_rq_fair(struct task_struct *p)
{
/*
* We are supposed to update the task to "current" time, then its up to date
@@ -5525,10 +5590,10 @@ static int migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
unsigned long src_faults, dst_faults;
int src_nid, dst_nid;
- if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
+ if (!static_branch_likely(&sched_numa_balancing))
return -1;
- if (!sched_feat(NUMA))
+ if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
return -1;
src_nid = cpu_to_node(env->src_cpu);
@@ -5934,7 +5999,7 @@ struct sg_lb_stats {
unsigned long sum_weighted_load; /* Weighted load of group's tasks */
unsigned long load_per_task;
unsigned long group_capacity;
- unsigned long group_usage; /* Total usage of the group */
+ unsigned long group_util; /* Total utilization of the group */
unsigned int sum_nr_running; /* Nr tasks running in the group */
unsigned int idle_cpus;
unsigned int group_weight;
@@ -6010,19 +6075,6 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
return load_idx;
}
-static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
- if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
- return sd->smt_gain / sd->span_weight;
-
- return SCHED_CAPACITY_SCALE;
-}
-
-unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
-{
- return default_scale_cpu_capacity(sd, cpu);
-}
-
static unsigned long scale_rt_capacity(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@@ -6052,16 +6104,9 @@ static unsigned long scale_rt_capacity(int cpu)
static void update_cpu_capacity(struct sched_domain *sd, int cpu)
{
- unsigned long capacity = SCHED_CAPACITY_SCALE;
+ unsigned long capacity = arch_scale_cpu_capacity(sd, cpu);
struct sched_group *sdg = sd->groups;
- if (sched_feat(ARCH_CAPACITY))
- capacity *= arch_scale_cpu_capacity(sd, cpu);
- else
- capacity *= default_scale_cpu_capacity(sd, cpu);
-
- capacity >>= SCHED_CAPACITY_SHIFT;
-
cpu_rq(cpu)->cpu_capacity_orig = capacity;
capacity *= scale_rt_capacity(cpu);
@@ -6187,8 +6232,8 @@ static inline int sg_imbalanced(struct sched_group *group)
* group_has_capacity returns true if the group has spare capacity that could
* be used by some tasks.
* We consider that a group has spare capacity if the * number of task is
- * smaller than the number of CPUs or if the usage is lower than the available
- * capacity for CFS tasks.
+ * smaller than the number of CPUs or if the utilization is lower than the
+ * available capacity for CFS tasks.
* For the latter, we use a threshold to stabilize the state, to take into
* account the variance of the tasks' load and to return true if the available
* capacity in meaningful for the load balancer.
@@ -6202,7 +6247,7 @@ group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs)
return true;
if ((sgs->group_capacity * 100) >
- (sgs->group_usage * env->sd->imbalance_pct))
+ (sgs->group_util * env->sd->imbalance_pct))
return true;
return false;
@@ -6223,15 +6268,15 @@ group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
return false;
if ((sgs->group_capacity * 100) <
- (sgs->group_usage * env->sd->imbalance_pct))
+ (sgs->group_util * env->sd->imbalance_pct))
return true;
return false;
}
-static enum group_type group_classify(struct lb_env *env,
- struct sched_group *group,
- struct sg_lb_stats *sgs)
+static inline enum
+group_type group_classify(struct sched_group *group,
+ struct sg_lb_stats *sgs)
{
if (sgs->group_no_capacity)
return group_overloaded;
@@ -6271,7 +6316,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,
load = source_load(i, load_idx);
sgs->group_load += load;
- sgs->group_usage += get_cpu_usage(i);
+ sgs->group_util += cpu_util(i);
sgs->sum_nr_running += rq->cfs.h_nr_running;
if (rq->nr_running > 1)
@@ -6296,7 +6341,7 @@ static inline void update_sg_lb_stats(struct lb_env *env,
sgs->group_weight = group->group_weight;
sgs->group_no_capacity = group_is_overloaded(env, sgs);
- sgs->group_type = group_classify(env, group, sgs);
+ sgs->group_type = group_classify(group, sgs);
}
/**
@@ -6430,7 +6475,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
group_has_capacity(env, &sds->local_stat) &&
(sgs->sum_nr_running > 1)) {
sgs->group_no_capacity = 1;
- sgs->group_type = group_overloaded;
+ sgs->group_type = group_classify(sg, sgs);
}
if (update_sd_pick_busiest(env, sds, sg, sgs)) {
@@ -7610,8 +7655,22 @@ static void rebalance_domains(struct rq *rq, enum cpu_idle_type idle)
* When the cpu is attached to null domain for ex, it will not be
* updated.
*/
- if (likely(update_next_balance))
+ if (likely(update_next_balance)) {
rq->next_balance = next_balance;
+
+#ifdef CONFIG_NO_HZ_COMMON
+ /*
+ * If this CPU has been elected to perform the nohz idle
+ * balance. Other idle CPUs have already rebalanced with
+ * nohz_idle_balance() and nohz.next_balance has been
+ * updated accordingly. This CPU is now running the idle load
+ * balance for itself and we need to update the
+ * nohz.next_balance accordingly.
+ */
+ if ((idle == CPU_IDLE) && time_after(nohz.next_balance, rq->next_balance))
+ nohz.next_balance = rq->next_balance;
+#endif
+ }
}
#ifdef CONFIG_NO_HZ_COMMON
@@ -7624,6 +7683,9 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
int this_cpu = this_rq->cpu;
struct rq *rq;
int balance_cpu;
+ /* Earliest time when we have to do rebalance again */
+ unsigned long next_balance = jiffies + 60*HZ;
+ int update_next_balance = 0;
if (idle != CPU_IDLE ||
!test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu)))
@@ -7655,10 +7717,19 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
rebalance_domains(rq, CPU_IDLE);
}
- if (time_after(this_rq->next_balance, rq->next_balance))
- this_rq->next_balance = rq->next_balance;
+ if (time_after(next_balance, rq->next_balance)) {
+ next_balance = rq->next_balance;
+ update_next_balance = 1;
+ }
}
- nohz.next_balance = this_rq->next_balance;
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the CPU is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance))
+ nohz.next_balance = next_balance;
end:
clear_bit(NOHZ_BALANCE_KICK, nohz_flags(this_cpu));
}
@@ -7811,7 +7882,7 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
entity_tick(cfs_rq, se, queued);
}
- if (numabalancing_enabled)
+ if (static_branch_unlikely(&sched_numa_balancing))
task_tick_numa(rq, curr);
}
@@ -7887,21 +7958,39 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
check_preempt_curr(rq, p, 0);
}
-static void switched_from_fair(struct rq *rq, struct task_struct *p)
+static inline bool vruntime_normalized(struct task_struct *p)
{
struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq = cfs_rq_of(se);
/*
- * Ensure the task's vruntime is normalized, so that when it's
- * switched back to the fair class the enqueue_entity(.flags=0) will
- * do the right thing.
+ * In both the TASK_ON_RQ_QUEUED and TASK_ON_RQ_MIGRATING cases,
+ * the dequeue_entity(.flags=0) will already have normalized the
+ * vruntime.
+ */
+ if (p->on_rq)
+ return true;
+
+ /*
+ * When !on_rq, vruntime of the task has usually NOT been normalized.
+ * But there are some cases where it has already been normalized:
*
- * If it's queued, then the dequeue_entity(.flags=0) will already
- * have normalized the vruntime, if it's !queued, then only when
- * the task is sleeping will it still have non-normalized vruntime.
+ * - A forked child which is waiting for being woken up by
+ * wake_up_new_task().
+ * - A task which has been woken up by try_to_wake_up() and
+ * waiting for actually being woken up by sched_ttwu_pending().
*/
- if (!task_on_rq_queued(p) && p->state != TASK_RUNNING) {
+ if (!se->sum_exec_runtime || p->state == TASK_WAKING)
+ return true;
+
+ return false;
+}
+
+static void detach_task_cfs_rq(struct task_struct *p)
+{
+ struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+ if (!vruntime_normalized(p)) {
/*
* Fix up our vruntime so that the current sleep doesn't
* cause 'unlimited' sleep bonus.
@@ -7910,28 +7999,14 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p)
se->vruntime -= cfs_rq->min_vruntime;
}
-#ifdef CONFIG_SMP
/* Catch up with the cfs_rq and remove our load when we leave */
- __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq), &se->avg,
- se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL);
-
- cfs_rq->avg.load_avg =
- max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0);
- cfs_rq->avg.load_sum =
- max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0);
- cfs_rq->avg.util_avg =
- max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0);
- cfs_rq->avg.util_sum =
- max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0);
-#endif
+ detach_entity_load_avg(cfs_rq, se);
}
-/*
- * We switched to the sched_fair class.
- */
-static void switched_to_fair(struct rq *rq, struct task_struct *p)
+static void attach_task_cfs_rq(struct task_struct *p)
{
struct sched_entity *se = &p->se;
+ struct cfs_rq *cfs_rq = cfs_rq_of(se);
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
@@ -7941,31 +8016,33 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p)
se->depth = se->parent ? se->parent->depth + 1 : 0;
#endif
- if (!task_on_rq_queued(p)) {
+ /* Synchronize task with its cfs_rq */
+ attach_entity_load_avg(cfs_rq, se);
+ if (!vruntime_normalized(p))
+ se->vruntime += cfs_rq->min_vruntime;
+}
+
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+ detach_task_cfs_rq(p);
+}
+
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
+{
+ attach_task_cfs_rq(p);
+
+ if (task_on_rq_queued(p)) {
/*
- * Ensure the task has a non-normalized vruntime when it is switched
- * back to the fair class with !queued, so that enqueue_entity() at
- * wake-up time will do the right thing.
- *
- * If it's queued, then the enqueue_entity(.flags=0) makes the task
- * has non-normalized vruntime, if it's !queued, then it still has
- * normalized vruntime.
+ * We were most likely switched from sched_rt, so
+ * kick off the schedule if running, otherwise just see
+ * if we can still preempt the current task.
*/
- if (p->state != TASK_RUNNING)
- se->vruntime += cfs_rq_of(se)->min_vruntime;
- return;
+ if (rq->curr == p)
+ resched_curr(rq);
+ else
+ check_preempt_curr(rq, p, 0);
}
-
- /*
- * We were most likely switched from sched_rt, so
- * kick off the schedule if running, otherwise just see
- * if we can still preempt the current task.
- */
- if (rq->curr == p)
- resched_curr(rq);
- else
- check_preempt_curr(rq, p, 0);
}
/* Account for a task changing its policy or group.
@@ -8000,56 +8077,16 @@ void init_cfs_rq(struct cfs_rq *cfs_rq)
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-static void task_move_group_fair(struct task_struct *p, int queued)
+static void task_move_group_fair(struct task_struct *p)
{
- struct sched_entity *se = &p->se;
- struct cfs_rq *cfs_rq;
-
- /*
- * If the task was not on the rq at the time of this cgroup movement
- * it must have been asleep, sleeping tasks keep their ->vruntime
- * absolute on their old rq until wakeup (needed for the fair sleeper
- * bonus in place_entity()).
- *
- * If it was on the rq, we've just 'preempted' it, which does convert
- * ->vruntime to a relative base.
- *
- * Make sure both cases convert their relative position when migrating
- * to another cgroup's rq. This does somewhat interfere with the
- * fair sleeper stuff for the first placement, but who cares.
- */
- /*
- * When !queued, vruntime of the task has usually NOT been normalized.
- * But there are some cases where it has already been normalized:
- *
- * - Moving a forked child which is waiting for being woken up by
- * wake_up_new_task().
- * - Moving a task which has been woken up by try_to_wake_up() and
- * waiting for actually being woken up by sched_ttwu_pending().
- *
- * To prevent boost or penalty in the new cfs_rq caused by delta
- * min_vruntime between the two cfs_rqs, we skip vruntime adjustment.
- */
- if (!queued && (!se->sum_exec_runtime || p->state == TASK_WAKING))
- queued = 1;
-
- if (!queued)
- se->vruntime -= cfs_rq_of(se)->min_vruntime;
+ detach_task_cfs_rq(p);
set_task_rq(p, task_cpu(p));
- se->depth = se->parent ? se->parent->depth + 1 : 0;
- if (!queued) {
- cfs_rq = cfs_rq_of(se);
- se->vruntime += cfs_rq->min_vruntime;
#ifdef CONFIG_SMP
- /* Virtually synchronize task with its new cfs_rq */
- p->se.avg.last_update_time = cfs_rq->avg.last_update_time;
- cfs_rq->avg.load_avg += p->se.avg.load_avg;
- cfs_rq->avg.load_sum += p->se.avg.load_sum;
- cfs_rq->avg.util_avg += p->se.avg.util_avg;
- cfs_rq->avg.util_sum += p->se.avg.util_sum;
+ /* Tell se's cfs_rq has been changed -- migrated */
+ p->se.avg.last_update_time = 0;
#endif
- }
+ attach_task_cfs_rq(p);
}
void free_fair_sched_group(struct task_group *tg)
diff --git a/kernel/sched/features.h b/kernel/sched/features.h
index 83a50e7ca533..69631fa46c2f 100644
--- a/kernel/sched/features.h
+++ b/kernel/sched/features.h
@@ -36,11 +36,6 @@ SCHED_FEAT(CACHE_HOT_BUDDY, true)
*/
SCHED_FEAT(WAKEUP_PREEMPTION, true)
-/*
- * Use arch dependent cpu capacity functions
- */
-SCHED_FEAT(ARCH_CAPACITY, true)
-
SCHED_FEAT(HRTICK, false)
SCHED_FEAT(DOUBLE_TICK, false)
SCHED_FEAT(LB_BIAS, true)
@@ -72,19 +67,5 @@ SCHED_FEAT(RT_PUSH_IPI, true)
SCHED_FEAT(FORCE_SD_OVERLAP, false)
SCHED_FEAT(RT_RUNTIME_SHARE, true)
SCHED_FEAT(LB_MIN, false)
+SCHED_FEAT(ATTACH_AGE_LOAD, true)
-/*
- * Apply the automatic NUMA scheduling policy. Enabled automatically
- * at runtime if running on a NUMA machine. Can be controlled via
- * numa_balancing=
- */
-#ifdef CONFIG_NUMA_BALANCING
-
-/*
- * NUMA will favor moving tasks towards nodes where a higher number of
- * hinting faults are recorded during active load balancing. It will
- * resist moving tasks towards nodes where a lower number of hinting
- * faults have been recorded.
- */
-SCHED_FEAT(NUMA, true)
-#endif
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index d2ea59364a1c..e3cc16312046 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -635,11 +635,11 @@ bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
/*
* We ran out of runtime, see if we can borrow some from our neighbours.
*/
-static int do_balance_runtime(struct rt_rq *rt_rq)
+static void do_balance_runtime(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
- int i, weight, more = 0;
+ int i, weight;
u64 rt_period;
weight = cpumask_weight(rd->span);
@@ -673,7 +673,6 @@ static int do_balance_runtime(struct rt_rq *rt_rq)
diff = rt_period - rt_rq->rt_runtime;
iter->rt_runtime -= diff;
rt_rq->rt_runtime += diff;
- more = 1;
if (rt_rq->rt_runtime == rt_period) {
raw_spin_unlock(&iter->rt_runtime_lock);
break;
@@ -683,8 +682,6 @@ static int do_balance_runtime(struct rt_rq *rt_rq)
raw_spin_unlock(&iter->rt_runtime_lock);
}
raw_spin_unlock(&rt_b->rt_runtime_lock);
-
- return more;
}
/*
@@ -796,26 +793,19 @@ static void __enable_runtime(struct rq *rq)
}
}
-static int balance_runtime(struct rt_rq *rt_rq)
+static void balance_runtime(struct rt_rq *rt_rq)
{
- int more = 0;
-
if (!sched_feat(RT_RUNTIME_SHARE))
- return more;
+ return;
if (rt_rq->rt_time > rt_rq->rt_runtime) {
raw_spin_unlock(&rt_rq->rt_runtime_lock);
- more = do_balance_runtime(rt_rq);
+ do_balance_runtime(rt_rq);
raw_spin_lock(&rt_rq->rt_runtime_lock);
}
-
- return more;
}
#else /* !CONFIG_SMP */
-static inline int balance_runtime(struct rt_rq *rt_rq)
-{
- return 0;
-}
+static inline void balance_runtime(struct rt_rq *rt_rq) {}
#endif /* CONFIG_SMP */
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6d2a119c7ad9..efd3bfc7e347 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -84,6 +84,10 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
*/
#define RUNTIME_INF ((u64)~0ULL)
+static inline int idle_policy(int policy)
+{
+ return policy == SCHED_IDLE;
+}
static inline int fair_policy(int policy)
{
return policy == SCHED_NORMAL || policy == SCHED_BATCH;
@@ -98,6 +102,11 @@ static inline int dl_policy(int policy)
{
return policy == SCHED_DEADLINE;
}
+static inline bool valid_policy(int policy)
+{
+ return idle_policy(policy) || fair_policy(policy) ||
+ rt_policy(policy) || dl_policy(policy);
+}
static inline int task_has_rt_policy(struct task_struct *p)
{
@@ -109,11 +118,6 @@ static inline int task_has_dl_policy(struct task_struct *p)
return dl_policy(p->policy);
}
-static inline bool dl_time_before(u64 a, u64 b)
-{
- return (s64)(a - b) < 0;
-}
-
/*
* Tells if entity @a should preempt entity @b.
*/
@@ -1003,17 +1007,7 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
-#ifdef CONFIG_NUMA_BALANCING
-#define sched_feat_numa(x) sched_feat(x)
-#ifdef CONFIG_SCHED_DEBUG
-#define numabalancing_enabled sched_feat_numa(NUMA)
-#else
-extern bool numabalancing_enabled;
-#endif /* CONFIG_SCHED_DEBUG */
-#else
-#define sched_feat_numa(x) (0)
-#define numabalancing_enabled (0)
-#endif /* CONFIG_NUMA_BALANCING */
+extern struct static_key_false sched_numa_balancing;
static inline u64 global_rt_period(void)
{
@@ -1157,16 +1151,18 @@ static const u32 prio_to_wmult[40] = {
/* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
};
-#define ENQUEUE_WAKEUP 1
-#define ENQUEUE_HEAD 2
+#define ENQUEUE_WAKEUP 0x01
+#define ENQUEUE_HEAD 0x02
#ifdef CONFIG_SMP
-#define ENQUEUE_WAKING 4 /* sched_class::task_waking was called */
+#define ENQUEUE_WAKING 0x04 /* sched_class::task_waking was called */
#else
-#define ENQUEUE_WAKING 0
+#define ENQUEUE_WAKING 0x00
#endif
-#define ENQUEUE_REPLENISH 8
+#define ENQUEUE_REPLENISH 0x08
+#define ENQUEUE_RESTORE 0x10
-#define DEQUEUE_SLEEP 1
+#define DEQUEUE_SLEEP 0x01
+#define DEQUEUE_SAVE 0x02
#define RETRY_TASK ((void *)-1UL)
@@ -1194,7 +1190,7 @@ struct sched_class {
#ifdef CONFIG_SMP
int (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
- void (*migrate_task_rq)(struct task_struct *p, int next_cpu);
+ void (*migrate_task_rq)(struct task_struct *p);
void (*task_waking) (struct task_struct *task);
void (*task_woken) (struct rq *this_rq, struct task_struct *task);
@@ -1227,7 +1223,7 @@ struct sched_class {
void (*update_curr) (struct rq *rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
- void (*task_move_group) (struct task_struct *p, int on_rq);
+ void (*task_move_group) (struct task_struct *p);
#endif
};
@@ -1405,6 +1401,17 @@ unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
}
#endif
+#ifndef arch_scale_cpu_capacity
+static __always_inline
+unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
+{
+ if (sd && (sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
+ return sd->smt_gain / sd->span_weight;
+
+ return SCHED_CAPACITY_SCALE;
+}
+#endif
+
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
diff --git a/kernel/smpboot.c b/kernel/smpboot.c
index a818cbc73e14..d264f59bff56 100644
--- a/kernel/smpboot.c
+++ b/kernel/smpboot.c
@@ -222,9 +222,8 @@ static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cp
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
- if (ht->pre_unpark)
- ht->pre_unpark(cpu);
- kthread_unpark(tsk);
+ if (!ht->selfparking)
+ kthread_unpark(tsk);
}
void smpboot_unpark_threads(unsigned int cpu)
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 12484e5d5c88..867bc20e1ef1 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -73,21 +73,24 @@ static void cpu_stop_signal_done(struct cpu_stop_done *done, bool executed)
}
}
+static void __cpu_stop_queue_work(struct cpu_stopper *stopper,
+ struct cpu_stop_work *work)
+{
+ list_add_tail(&work->list, &stopper->works);
+ wake_up_process(stopper->thread);
+}
+
/* queue @work to @stopper. if offline, @work is completed immediately */
static void cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
-
unsigned long flags;
spin_lock_irqsave(&stopper->lock, flags);
-
- if (stopper->enabled) {
- list_add_tail(&work->list, &stopper->works);
- wake_up_process(stopper->thread);
- } else
+ if (stopper->enabled)
+ __cpu_stop_queue_work(stopper, work);
+ else
cpu_stop_signal_done(work->done, false);
-
spin_unlock_irqrestore(&stopper->lock, flags);
}
@@ -213,6 +216,31 @@ static int multi_cpu_stop(void *data)
return err;
}
+static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1,
+ int cpu2, struct cpu_stop_work *work2)
+{
+ struct cpu_stopper *stopper1 = per_cpu_ptr(&cpu_stopper, cpu1);
+ struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2);
+ int err;
+
+ lg_double_lock(&stop_cpus_lock, cpu1, cpu2);
+ spin_lock_irq(&stopper1->lock);
+ spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
+
+ err = -ENOENT;
+ if (!stopper1->enabled || !stopper2->enabled)
+ goto unlock;
+
+ err = 0;
+ __cpu_stop_queue_work(stopper1, work1);
+ __cpu_stop_queue_work(stopper2, work2);
+unlock:
+ spin_unlock(&stopper2->lock);
+ spin_unlock_irq(&stopper1->lock);
+ lg_double_unlock(&stop_cpus_lock, cpu1, cpu2);
+
+ return err;
+}
/**
* stop_two_cpus - stops two cpus
* @cpu1: the cpu to stop
@@ -247,24 +275,13 @@ int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *
cpu_stop_init_done(&done, 2);
set_state(&msdata, MULTI_STOP_PREPARE);
- /*
- * If we observe both CPUs active we know _cpu_down() cannot yet have
- * queued its stop_machine works and therefore ours will get executed
- * first. Or its not either one of our CPUs that's getting unplugged,
- * in which case we don't care.
- *
- * This relies on the stopper workqueues to be FIFO.
- */
- if (!cpu_active(cpu1) || !cpu_active(cpu2)) {
+ if (cpu1 > cpu2)
+ swap(cpu1, cpu2);
+ if (cpu_stop_queue_two_works(cpu1, &work1, cpu2, &work2)) {
preempt_enable();
return -ENOENT;
}
- lg_double_lock(&stop_cpus_lock, cpu1, cpu2);
- cpu_stop_queue_work(cpu1, &work1);
- cpu_stop_queue_work(cpu2, &work2);
- lg_double_unlock(&stop_cpus_lock, cpu1, cpu2);
-
preempt_enable();
wait_for_completion(&done.completion);
@@ -452,6 +469,18 @@ static void cpu_stopper_thread(unsigned int cpu)
}
}
+void stop_machine_park(int cpu)
+{
+ struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
+ /*
+ * Lockless. cpu_stopper_thread() will take stopper->lock and flush
+ * the pending works before it parks, until then it is fine to queue
+ * the new works.
+ */
+ stopper->enabled = false;
+ kthread_park(stopper->thread);
+}
+
extern void sched_set_stop_task(int cpu, struct task_struct *stop);
static void cpu_stop_create(unsigned int cpu)
@@ -462,26 +491,16 @@ static void cpu_stop_create(unsigned int cpu)
static void cpu_stop_park(unsigned int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
- struct cpu_stop_work *work, *tmp;
- unsigned long flags;
- /* drain remaining works */
- spin_lock_irqsave(&stopper->lock, flags);
- list_for_each_entry_safe(work, tmp, &stopper->works, list) {
- list_del_init(&work->list);
- cpu_stop_signal_done(work->done, false);
- }
- stopper->enabled = false;
- spin_unlock_irqrestore(&stopper->lock, flags);
+ WARN_ON(!list_empty(&stopper->works));
}
-static void cpu_stop_unpark(unsigned int cpu)
+void stop_machine_unpark(int cpu)
{
struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
- spin_lock_irq(&stopper->lock);
stopper->enabled = true;
- spin_unlock_irq(&stopper->lock);
+ kthread_unpark(stopper->thread);
}
static struct smp_hotplug_thread cpu_stop_threads = {
@@ -490,9 +509,7 @@ static struct smp_hotplug_thread cpu_stop_threads = {
.thread_fn = cpu_stopper_thread,
.thread_comm = "migration/%u",
.create = cpu_stop_create,
- .setup = cpu_stop_unpark,
.park = cpu_stop_park,
- .pre_unpark = cpu_stop_unpark,
.selfparking = true,
};
@@ -508,6 +525,7 @@ static int __init cpu_stop_init(void)
}
BUG_ON(smpboot_register_percpu_thread(&cpu_stop_threads));
+ stop_machine_unpark(raw_smp_processor_id());
stop_machine_initialized = true;
return 0;
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index b0623ac785a2..00611e95a8ee 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5697,7 +5697,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
}
static void
-ftrace_graph_probe_sched_switch(void *ignore,
+ftrace_graph_probe_sched_switch(void *ignore, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
unsigned long long timestamp;
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index f270088e9929..4c896a0101bd 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -16,7 +16,8 @@ static int sched_ref;
static DEFINE_MUTEX(sched_register_mutex);
static void
-probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next)
+probe_sched_switch(void *ignore, bool preempt,
+ struct task_struct *prev, struct task_struct *next)
{
if (unlikely(!sched_ref))
return;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 12cbe77b4136..4bcfbac289ff 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -420,7 +420,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
}
static void notrace
-probe_wakeup_sched_switch(void *ignore,
+probe_wakeup_sched_switch(void *ignore, bool preempt,
struct task_struct *prev, struct task_struct *next)
{
struct trace_array_cpu *data;
--
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