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Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull scheduler updates from Ingo Molnar:

 - massive CPU hotplug rework (Thomas Gleixner)

 - improve migration fairness (Peter Zijlstra)

 - CPU load calculation updates/cleanups (Yuyang Du)

 - cpufreq updates (Steve Muckle)

 - nohz optimizations (Frederic Weisbecker)

 - switch_mm() micro-optimization on x86 (Andy Lutomirski)

 - ... lots of other enhancements, fixes and cleanups.

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (66 commits)
  ARM: Hide finish_arch_post_lock_switch() from modules
  sched/core: Provide a tsk_nr_cpus_allowed() helper
  sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowed
  sched/loadavg: Fix loadavg artifacts on fully idle and on fully loaded systems
  sched/fair: Correct unit of load_above_capacity
  sched/fair: Clean up scale confusion
  sched/nohz: Fix affine unpinned timers mess
  sched/fair: Fix fairness issue on migration
  sched/core: Kill sched_class::task_waking to clean up the migration logic
  sched/fair: Prepare to fix fairness problems on migration
  sched/fair: Move record_wakee()
  sched/core: Fix comment typo in wake_q_add()
  sched/core: Remove unused variable
  sched: Make hrtick_notifier an explicit call
  sched/fair: Make ilb_notifier an explicit call
  sched/hotplug: Make activate() the last hotplug step
  sched/hotplug: Move migration CPU_DYING to sched_cpu_dying()
  sched/migration: Move CPU_ONLINE into scheduler state
  sched/migration: Move calc_load_migrate() into CPU_DYING
  sched/migration: Move prepare transition to SCHED_STARTING state
  ...
This commit is contained in:
Linus Torvalds
2016-05-16 14:47:16 -07:00
parent cf6ed9a668 ef0491ea17
commit 825a3b2605
31 changed files with 1348 additions and 946 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
kernel/cpu.c
View File

@@ -703,21 +703,6 @@ static int takedown_cpu(unsigned int cpu)
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int err;
/*
* By now 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.
*
* For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
* not imply sync_sched(), so wait for both.
*
* Do sync before park smpboot threads to take care the rcu boost case.
*/
if (IS_ENABLED(CONFIG_PREEMPT))
synchronize_rcu_mult(call_rcu, call_rcu_sched);
else
synchronize_rcu();
/* Park the smpboot threads */
kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread);
smpboot_park_threads(cpu);
@@ -923,8 +908,6 @@ void cpuhp_online_idle(enum cpuhp_state state)
st->state = CPUHP_AP_ONLINE_IDLE;
/* The cpu is marked online, set it active now */
set_cpu_active(cpu, true);
/* Unpark the stopper thread and the hotplug thread of this cpu */
stop_machine_unpark(cpu);
kthread_unpark(st->thread);
@@ -1236,6 +1219,12 @@ static struct cpuhp_step cpuhp_ap_states[] = {
.name = "ap:offline",
.cant_stop = true,
},
/* First state is scheduler control. Interrupts are disabled */
[CPUHP_AP_SCHED_STARTING] = {
.name = "sched:starting",
.startup = sched_cpu_starting,
.teardown = sched_cpu_dying,
},
/*
* Low level startup/teardown notifiers. Run with interrupts
* disabled. Will be removed once the notifiers are converted to
@@ -1274,6 +1263,15 @@ static struct cpuhp_step cpuhp_ap_states[] = {
* The dynamically registered state space is here
*/
#ifdef CONFIG_SMP
/* Last state is scheduler control setting the cpu active */
[CPUHP_AP_ACTIVE] = {
.name = "sched:active",
.startup = sched_cpu_activate,
.teardown = sched_cpu_deactivate,
},
#endif
/* CPU is fully up and running. */
[CPUHP_ONLINE] = {
.name = "online",

71
kernel/locking/lockdep.c
View File

@@ -45,6 +45,7 @@
#include <linux/bitops.h>
#include <linux/gfp.h>
#include <linux/kmemcheck.h>
#include <linux/random.h>
#include <asm/sections.h>
@@ -3585,7 +3586,35 @@ static int __lock_is_held(struct lockdep_map *lock)
return 0;
}
static void __lock_pin_lock(struct lockdep_map *lock)
static struct pin_cookie __lock_pin_lock(struct lockdep_map *lock)
{
struct pin_cookie cookie = NIL_COOKIE;
struct task_struct *curr = current;
int i;
if (unlikely(!debug_locks))
return cookie;
for (i = 0; i < curr->lockdep_depth; i++) {
struct held_lock *hlock = curr->held_locks + i;
if (match_held_lock(hlock, lock)) {
/*
* Grab 16bits of randomness; this is sufficient to not
* be guessable and still allows some pin nesting in
* our u32 pin_count.
*/
cookie.val = 1 + (prandom_u32() >> 16);
hlock->pin_count += cookie.val;
return cookie;
}
}
WARN(1, "pinning an unheld lock\n");
return cookie;
}
static void __lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3597,7 +3626,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
struct held_lock *hlock = curr->held_locks + i;
if (match_held_lock(hlock, lock)) {
hlock->pin_count++;
hlock->pin_count += cookie.val;
return;
}
}
@@ -3605,7 +3634,7 @@ static void __lock_pin_lock(struct lockdep_map *lock)
WARN(1, "pinning an unheld lock\n");
}
static void __lock_unpin_lock(struct lockdep_map *lock)
static void __lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
struct task_struct *curr = current;
int i;
@@ -3620,7 +3649,11 @@ static void __lock_unpin_lock(struct lockdep_map *lock)
if (WARN(!hlock->pin_count, "unpinning an unpinned lock\n"))
return;
hlock->pin_count--;
hlock->pin_count -= cookie.val;
if (WARN((int)hlock->pin_count < 0, "pin count corrupted\n"))
hlock->pin_count = 0;
return;
}
}
@@ -3751,24 +3784,27 @@ int lock_is_held(struct lockdep_map *lock)
}
EXPORT_SYMBOL_GPL(lock_is_held);
void lock_pin_lock(struct lockdep_map *lock)
struct pin_cookie lock_pin_lock(struct lockdep_map *lock)
{
struct pin_cookie cookie = NIL_COOKIE;
unsigned long flags;
if (unlikely(current->lockdep_recursion))
return;
return cookie;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
__lock_pin_lock(lock);
cookie = __lock_pin_lock(lock);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
return cookie;
}
EXPORT_SYMBOL_GPL(lock_pin_lock);
void lock_unpin_lock(struct lockdep_map *lock)
void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
unsigned long flags;
@@ -3779,7 +3815,24 @@ void lock_unpin_lock(struct lockdep_map *lock)
check_flags(flags);
current->lockdep_recursion = 1;
__lock_unpin_lock(lock);
__lock_repin_lock(lock, cookie);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(lock_repin_lock);
void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie cookie)
{
unsigned long flags;
if (unlikely(current->lockdep_recursion))
return;
raw_local_irq_save(flags);
check_flags(flags);
current->lockdep_recursion = 1;
__lock_unpin_lock(lock, cookie);
current->lockdep_recursion = 0;
raw_local_irq_restore(flags);
}

48
kernel/sched/clock.c
View File

@@ -318,6 +318,7 @@ u64 sched_clock_cpu(int cpu)
return clock;
}
EXPORT_SYMBOL_GPL(sched_clock_cpu);
void sched_clock_tick(void)
{
@@ -363,39 +364,6 @@ void sched_clock_idle_wakeup_event(u64 delta_ns)
}
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
/*
* As outlined at the top, provides a fast, high resolution, nanosecond
* time source that is monotonic per cpu argument and has bounded drift
* between cpus.
*
* ######################### BIG FAT WARNING ##########################
* # when comparing cpu_clock(i) to cpu_clock(j) for i != j, time can #
* # go backwards !! #
* ####################################################################
*/
u64 cpu_clock(int cpu)
{
if (!sched_clock_stable())
return sched_clock_cpu(cpu);
return sched_clock();
}
/*
* Similar to cpu_clock() for the current cpu. Time will only be observed
* to be monotonic if care is taken to only compare timestampt taken on the
* same CPU.
*
* See cpu_clock().
*/
u64 local_clock(void)
{
if (!sched_clock_stable())
return sched_clock_cpu(raw_smp_processor_id());
return sched_clock();
}
#else /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
void sched_clock_init(void)
@@ -410,22 +378,8 @@ u64 sched_clock_cpu(int cpu)
return sched_clock();
}
u64 cpu_clock(int cpu)
{
return sched_clock();
}
u64 local_clock(void)
{
return sched_clock();
}
#endif /* CONFIG_HAVE_UNSTABLE_SCHED_CLOCK */
EXPORT_SYMBOL_GPL(cpu_clock);
EXPORT_SYMBOL_GPL(local_clock);
/*
* Running clock - returns the time that has elapsed while a guest has been
* running.

749
kernel/sched/core.c
View File

File diff suppressed because it is too large Load Diff

147
kernel/sched/cpuacct.c
View File

@@ -25,11 +25,22 @@ enum cpuacct_stat_index {
CPUACCT_STAT_NSTATS,
};
enum cpuacct_usage_index {
CPUACCT_USAGE_USER, /* ... user mode */
CPUACCT_USAGE_SYSTEM, /* ... kernel mode */
CPUACCT_USAGE_NRUSAGE,
};
struct cpuacct_usage {
u64 usages[CPUACCT_USAGE_NRUSAGE];
};
/* track cpu usage of a group of tasks and its child groups */
struct cpuacct {
struct cgroup_subsys_state css;
/* cpuusage holds pointer to a u64-type object on every cpu */
u64 __percpu *cpuusage;
struct cpuacct_usage __percpu *cpuusage;
struct kernel_cpustat __percpu *cpustat;
};
@@ -49,7 +60,7 @@ static inline struct cpuacct *parent_ca(struct cpuacct *ca)
return css_ca(ca->css.parent);
}
static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage);
static struct cpuacct root_cpuacct = {
.cpustat = &kernel_cpustat,
.cpuusage = &root_cpuacct_cpuusage,
@@ -68,7 +79,7 @@ cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
if (!ca)
goto out;
ca->cpuusage = alloc_percpu(u64);
ca->cpuusage = alloc_percpu(struct cpuacct_usage);
if (!ca->cpuusage)
goto out_free_ca;
@@ -96,20 +107,37 @@ static void cpuacct_css_free(struct cgroup_subsys_state *css)
kfree(ca);
}
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
enum cpuacct_usage_index index)
{
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
u64 data;
/*
* We allow index == CPUACCT_USAGE_NRUSAGE here to read
* the sum of suages.
*/
BUG_ON(index > CPUACCT_USAGE_NRUSAGE);
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit read safe on 32-bit platforms.
*/
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
data = *cpuusage;
#endif
if (index == CPUACCT_USAGE_NRUSAGE) {
int i = 0;
data = 0;
for (i = 0; i < CPUACCT_USAGE_NRUSAGE; i++)
data += cpuusage->usages[i];
} else {
data = cpuusage->usages[index];
}
#ifndef CONFIG_64BIT
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
#else
data = *cpuusage;
#endif
return data;
@@ -117,69 +145,103 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
{
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
int i;
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit write safe on 32-bit platforms.
*/
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
*cpuusage = val;
#endif
for (i = 0; i < CPUACCT_USAGE_NRUSAGE; i++)
cpuusage->usages[i] = val;
#ifndef CONFIG_64BIT
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
#else
*cpuusage = val;
#endif
}
/* return total cpu usage (in nanoseconds) of a group */
static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
static u64 __cpuusage_read(struct cgroup_subsys_state *css,
enum cpuacct_usage_index index)
{
struct cpuacct *ca = css_ca(css);
u64 totalcpuusage = 0;
int i;
for_each_present_cpu(i)
totalcpuusage += cpuacct_cpuusage_read(ca, i);
for_each_possible_cpu(i)
totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
return totalcpuusage;
}
static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_USAGE_USER);
}
static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_USAGE_SYSTEM);
}
static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_USAGE_NRUSAGE);
}
static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
u64 val)
{
struct cpuacct *ca = css_ca(css);
int err = 0;
int i;
int cpu;
/*
* Only allow '0' here to do a reset.
*/
if (val) {
err = -EINVAL;
goto out;
}
if (val)
return -EINVAL;
for_each_present_cpu(i)
cpuacct_cpuusage_write(ca, i, 0);
for_each_possible_cpu(cpu)
cpuacct_cpuusage_write(ca, cpu, 0);
out:
return err;
return 0;
}
static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
static int __cpuacct_percpu_seq_show(struct seq_file *m,
enum cpuacct_usage_index index)
{
struct cpuacct *ca = css_ca(seq_css(m));
u64 percpu;
int i;
for_each_present_cpu(i) {
percpu = cpuacct_cpuusage_read(ca, i);
for_each_possible_cpu(i) {
percpu = cpuacct_cpuusage_read(ca, i, index);
seq_printf(m, "%llu ", (unsigned long long) percpu);
}
seq_printf(m, "\n");
return 0;
}
static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_USER);
}
static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_SYSTEM);
}
static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_USAGE_NRUSAGE);
}
static const char * const cpuacct_stat_desc[] = {
[CPUACCT_STAT_USER] = "user",
[CPUACCT_STAT_SYSTEM] = "system",
@@ -191,7 +253,7 @@ static int cpuacct_stats_show(struct seq_file *sf, void *v)
int cpu;
s64 val = 0;
for_each_online_cpu(cpu) {
for_each_possible_cpu(cpu) {
struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
val += kcpustat->cpustat[CPUTIME_USER];
val += kcpustat->cpustat[CPUTIME_NICE];
@@ -200,7 +262,7 @@ static int cpuacct_stats_show(struct seq_file *sf, void *v)
seq_printf(sf, "%s %lld\n", cpuacct_stat_desc[CPUACCT_STAT_USER], val);
val = 0;
for_each_online_cpu(cpu) {
for_each_possible_cpu(cpu) {
struct kernel_cpustat *kcpustat = per_cpu_ptr(ca->cpustat, cpu);
val += kcpustat->cpustat[CPUTIME_SYSTEM];
val += kcpustat->cpustat[CPUTIME_IRQ];
@@ -219,10 +281,26 @@ static struct cftype files[] = {
.read_u64 = cpuusage_read,
.write_u64 = cpuusage_write,
},
{
.name = "usage_user",
.read_u64 = cpuusage_user_read,
},
{
.name = "usage_sys",
.read_u64 = cpuusage_sys_read,
},
{
.name = "usage_percpu",
.seq_show = cpuacct_percpu_seq_show,
},
{
.name = "usage_percpu_user",
.seq_show = cpuacct_percpu_user_seq_show,
},
{
.name = "usage_percpu_sys",
.seq_show = cpuacct_percpu_sys_seq_show,
},
{
.name = "stat",
.seq_show = cpuacct_stats_show,
@@ -238,10 +316,17 @@ static struct cftype files[] = {
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
struct cpuacct *ca;
int index = CPUACCT_USAGE_SYSTEM;
struct pt_regs *regs = task_pt_regs(tsk);
if (regs && user_mode(regs))
index = CPUACCT_USAGE_USER;
rcu_read_lock();
for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
*this_cpu_ptr(ca->cpuusage) += cputime;
this_cpu_ptr(ca->cpuusage)->usages[index] += cputime;
rcu_read_unlock();
}

4
kernel/sched/cpudeadline.c
View File

@@ -103,10 +103,10 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
const struct sched_dl_entity *dl_se = &p->dl;
if (later_mask &&
cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
cpumask_and(later_mask, cp->free_cpus, tsk_cpus_allowed(p))) {
best_cpu = cpumask_any(later_mask);
goto out;
} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
} else if (cpumask_test_cpu(cpudl_maximum(cp), tsk_cpus_allowed(p)) &&
dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
best_cpu = cpudl_maximum(cp);
if (later_mask)

4
kernel/sched/cpupri.c
View File

@@ -103,11 +103,11 @@ int cpupri_find(struct cpupri *cp, struct task_struct *p,
if (skip)
continue;
if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)
if (cpumask_any_and(tsk_cpus_allowed(p), vec->mask) >= nr_cpu_ids)
continue;
if (lowest_mask) {
cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);
cpumask_and(lowest_mask, tsk_cpus_allowed(p), vec->mask);
/*
* We have to ensure that we have at least one bit

55
kernel/sched/deadline.c
View File

@@ -134,7 +134,7 @@ static void inc_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
{
struct task_struct *p = dl_task_of(dl_se);
if (p->nr_cpus_allowed > 1)
if (tsk_nr_cpus_allowed(p) > 1)
dl_rq->dl_nr_migratory++;
update_dl_migration(dl_rq);
@@ -144,7 +144,7 @@ static void dec_dl_migration(struct sched_dl_entity *dl_se, struct dl_rq *dl_rq)
{
struct task_struct *p = dl_task_of(dl_se);
if (p->nr_cpus_allowed > 1)
if (tsk_nr_cpus_allowed(p) > 1)
dl_rq->dl_nr_migratory--;
update_dl_migration(dl_rq);
@@ -591,10 +591,10 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
struct sched_dl_entity,
dl_timer);
struct task_struct *p = dl_task_of(dl_se);
unsigned long flags;
struct rq_flags rf;
struct rq *rq;
rq = task_rq_lock(p, &flags);
rq = task_rq_lock(p, &rf);
/*
* The task might have changed its scheduling policy to something
@@ -670,14 +670,14 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
* Nothing relies on rq->lock after this, so its safe to drop
* rq->lock.
*/
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, rf.cookie);
push_dl_task(rq);
lockdep_pin_lock(&rq->lock);
lockdep_repin_lock(&rq->lock, rf.cookie);
}
#endif
unlock:
task_rq_unlock(rq, p, &flags);
task_rq_unlock(rq, p, &rf);
/*
* This can free the task_struct, including this hrtimer, do not touch
@@ -717,10 +717,6 @@ static void update_curr_dl(struct rq *rq)
if (!dl_task(curr) || !on_dl_rq(dl_se))
return;
/* Kick cpufreq (see the comment in linux/cpufreq.h). */
if (cpu_of(rq) == smp_processor_id())
cpufreq_trigger_update(rq_clock(rq));
/*
* Consumed budget is computed considering the time as
* observed by schedulable tasks (excluding time spent
@@ -736,6 +732,10 @@ static void update_curr_dl(struct rq *rq)
return;
}
/* kick cpufreq (see the comment in linux/cpufreq.h). */
if (cpu_of(rq) == smp_processor_id())
cpufreq_trigger_update(rq_clock(rq));
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));
@@ -966,7 +966,7 @@ static void enqueue_task_dl(struct rq *rq, struct task_struct *p, int flags)
enqueue_dl_entity(&p->dl, pi_se, flags);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
if (!task_current(rq, p) && tsk_nr_cpus_allowed(p) > 1)
enqueue_pushable_dl_task(rq, p);
}
@@ -1040,9 +1040,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
* try to make it stay here, it might be important.
*/
if (unlikely(dl_task(curr)) &&
(curr->nr_cpus_allowed < 2 ||
(tsk_nr_cpus_allowed(curr) < 2 ||
!dl_entity_preempt(&p->dl, &curr->dl)) &&
(p->nr_cpus_allowed > 1)) {
(tsk_nr_cpus_allowed(p) > 1)) {
int target = find_later_rq(p);
if (target != -1 &&
@@ -1063,7 +1063,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
* Current can't be migrated, useless to reschedule,
* let's hope p can move out.
*/
if (rq->curr->nr_cpus_allowed == 1 ||
if (tsk_nr_cpus_allowed(rq->curr) == 1 ||
cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
return;
@@ -1071,7 +1071,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
* p is migratable, so let's not schedule it and
* see if it is pushed or pulled somewhere else.
*/
if (p->nr_cpus_allowed != 1 &&
if (tsk_nr_cpus_allowed(p) != 1 &&
cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
return;
@@ -1125,7 +1125,8 @@ static struct sched_dl_entity *pick_next_dl_entity(struct rq *rq,
return rb_entry(left, struct sched_dl_entity, rb_node);
}
struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev)
struct task_struct *
pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct sched_dl_entity *dl_se;
struct task_struct *p;
@@ -1140,9 +1141,9 @@ struct task_struct *pick_next_task_dl(struct rq *rq, struct task_struct *prev)
* disabled avoiding further scheduler activity on it and we're
* being very careful to re-start the picking loop.
*/
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, cookie);
pull_dl_task(rq);
lockdep_pin_lock(&rq->lock);
lockdep_repin_lock(&rq->lock, cookie);
/*
* pull_rt_task() can drop (and re-acquire) rq->lock; this
* means a stop task can slip in, in which case we need to
@@ -1185,7 +1186,7 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
{
update_curr_dl(rq);
if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
if (on_dl_rq(&p->dl) && tsk_nr_cpus_allowed(p) > 1)
enqueue_pushable_dl_task(rq, p);
}
@@ -1286,7 +1287,7 @@ static int find_later_rq(struct task_struct *task)
if (unlikely(!later_mask))
return -1;
if (task->nr_cpus_allowed == 1)
if (tsk_nr_cpus_allowed(task) == 1)
return -1;
/*
@@ -1392,7 +1393,7 @@ static struct rq *find_lock_later_rq(struct task_struct *task, struct rq *rq)
if (double_lock_balance(rq, later_rq)) {
if (unlikely(task_rq(task) != rq ||
!cpumask_test_cpu(later_rq->cpu,
&task->cpus_allowed) ||
tsk_cpus_allowed(task)) ||
task_running(rq, task) ||
!dl_task(task) ||
!task_on_rq_queued(task))) {
@@ -1432,7 +1433,7 @@ static struct task_struct *pick_next_pushable_dl_task(struct rq *rq)
BUG_ON(rq->cpu != task_cpu(p));
BUG_ON(task_current(rq, p));
BUG_ON(p->nr_cpus_allowed <= 1);
BUG_ON(tsk_nr_cpus_allowed(p) <= 1);
BUG_ON(!task_on_rq_queued(p));
BUG_ON(!dl_task(p));
@@ -1471,7 +1472,7 @@ retry:
*/
if (dl_task(rq->curr) &&
dl_time_before(next_task->dl.deadline, rq->curr->dl.deadline) &&
rq->curr->nr_cpus_allowed > 1) {
tsk_nr_cpus_allowed(rq->curr) > 1) {
resched_curr(rq);
return 0;
}
@@ -1618,9 +1619,9 @@ static void task_woken_dl(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
p->nr_cpus_allowed > 1 &&
tsk_nr_cpus_allowed(p) > 1 &&
dl_task(rq->curr) &&
(rq->curr->nr_cpus_allowed < 2 ||
(tsk_nr_cpus_allowed(rq->curr) < 2 ||
!dl_entity_preempt(&p->dl, &rq->curr->dl))) {
push_dl_tasks(rq);
}
@@ -1724,7 +1725,7 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
if (p->nr_cpus_allowed > 1 && rq->dl.overloaded)
if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
queue_push_tasks(rq);
#else
if (dl_task(rq->curr))

10
kernel/sched/debug.c
View File

@@ -626,15 +626,16 @@ do { \
#undef P
#undef PN
#ifdef CONFIG_SCHEDSTATS
#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
#define P64(n) SEQ_printf(m, " .%-30s: %Ld\n", #n, rq->n);
#ifdef CONFIG_SMP
#define P64(n) SEQ_printf(m, " .%-30s: %Ld\n", #n, rq->n);
P64(avg_idle);
P64(max_idle_balance_cost);
#undef P64
#endif
#ifdef CONFIG_SCHEDSTATS
#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
if (schedstat_enabled()) {
P(yld_count);
P(sched_count);
@@ -644,7 +645,6 @@ do { \
}
#undef P
#undef P64
#endif
spin_lock_irqsave(&sched_debug_lock, flags);
print_cfs_stats(m, cpu);

551
kernel/sched/fair.c
View File

@@ -204,7 +204,7 @@ static void __update_inv_weight(struct load_weight *lw)
* OR
* (delta_exec * (weight * lw->inv_weight)) >> WMULT_SHIFT
*
* Either weight := NICE_0_LOAD and lw \e prio_to_wmult[], in which case
* Either weight := NICE_0_LOAD and lw \e sched_prio_to_wmult[], in which case
* we're guaranteed shift stays positive because inv_weight is guaranteed to
* fit 32 bits, and NICE_0_LOAD gives another 10 bits; therefore shift >= 22.
*
@@ -682,17 +682,68 @@ void init_entity_runnable_average(struct sched_entity *se)
sa->period_contrib = 1023;
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 = sa->util_avg * LOAD_AVG_MAX;
/*
* At this point, util_avg won't be used in select_task_rq_fair anyway
*/
sa->util_avg = 0;
sa->util_sum = 0;
/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
}
/*
* With new tasks being created, their initial util_avgs are extrapolated
* based on the cfs_rq's current util_avg:
*
* util_avg = cfs_rq->util_avg / (cfs_rq->load_avg + 1) * se.load.weight
*
* However, in many cases, the above util_avg does not give a desired
* value. Moreover, the sum of the util_avgs may be divergent, such
* as when the series is a harmonic series.
*
* To solve this problem, we also cap the util_avg of successive tasks to
* only 1/2 of the left utilization budget:
*
* util_avg_cap = (1024 - cfs_rq->avg.util_avg) / 2^n
*
* where n denotes the nth task.
*
* For example, a simplest series from the beginning would be like:
*
* task util_avg: 512, 256, 128, 64, 32, 16, 8, ...
* cfs_rq util_avg: 512, 768, 896, 960, 992, 1008, 1016, ...
*
* Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap)
* if util_avg > util_avg_cap.
*/
void post_init_entity_util_avg(struct sched_entity *se)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
struct sched_avg *sa = &se->avg;
long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;
if (cap > 0) {
if (cfs_rq->avg.util_avg != 0) {
sa->util_avg = cfs_rq->avg.util_avg * se->load.weight;
sa->util_avg /= (cfs_rq->avg.load_avg + 1);
if (sa->util_avg > cap)
sa->util_avg = cap;
} else {
sa->util_avg = cap;
}
sa->util_sum = sa->util_avg * LOAD_AVG_MAX;
}
}
static inline unsigned long cfs_rq_runnable_load_avg(struct cfs_rq *cfs_rq);
static inline unsigned long cfs_rq_load_avg(struct cfs_rq *cfs_rq);
#else
void init_entity_runnable_average(struct sched_entity *se)
{
}
void post_init_entity_util_avg(struct sched_entity *se)
{
}
#endif
/*
@@ -2437,10 +2488,12 @@ account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
update_load_sub(&cfs_rq->load, se->load.weight);
if (!parent_entity(se))
update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
#ifdef CONFIG_SMP
if (entity_is_task(se)) {
account_numa_dequeue(rq_of(cfs_rq), task_of(se));
list_del_init(&se->group_node);
}
#endif
cfs_rq->nr_running--;
}
@@ -2549,6 +2602,16 @@ static const u32 runnable_avg_yN_sum[] = {
17718,18340,18949,19545,20128,20698,21256,21802,22336,22859,23371,
};
/*
* Precomputed \Sum y^k { 1<=k<=n, where n%32=0). Values are rolled down to
* lower integers. See Documentation/scheduler/sched-avg.txt how these
* were generated:
*/
static const u32 __accumulated_sum_N32[] = {
0, 23371, 35056, 40899, 43820, 45281,
46011, 46376, 46559, 46650, 46696, 46719,
};
/*
* Approximate:
* val * y^n, where y^32 ~= 0.5 (~1 scheduling period)
@@ -2597,22 +2660,13 @@ static u32 __compute_runnable_contrib(u64 n)
else if (unlikely(n >= LOAD_AVG_MAX_N))
return LOAD_AVG_MAX;
/* Compute \Sum k^n combining precomputed values for k^i, \Sum k^j */
do {
contrib /= 2; /* y^LOAD_AVG_PERIOD = 1/2 */
contrib += runnable_avg_yN_sum[LOAD_AVG_PERIOD];
n -= LOAD_AVG_PERIOD;
} while (n > LOAD_AVG_PERIOD);
/* Since n < LOAD_AVG_MAX_N, n/LOAD_AVG_PERIOD < 11 */
contrib = __accumulated_sum_N32[n/LOAD_AVG_PERIOD];
n %= LOAD_AVG_PERIOD;
contrib = decay_load(contrib, 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)
/*
@@ -2821,55 +2875,11 @@ static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) {}
static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq);
/* Group cfs_rq's load_avg is used for task_h_load and update_cfs_share */
static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq)
{
struct sched_avg *sa = &cfs_rq->avg;
int decayed, removed = 0;
if (atomic_long_read(&cfs_rq->removed_load_avg)) {
s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
sa->load_avg = max_t(long, sa->load_avg - r, 0);
sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);
removed = 1;
}
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, 0);
}
decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
scale_load_down(cfs_rq->load.weight), cfs_rq->curr != NULL, cfs_rq);
#ifndef CONFIG_64BIT
smp_wmb();
cfs_rq->load_last_update_time_copy = sa->last_update_time;
#endif
return decayed || removed;
}
/* Update task and its cfs_rq load average */
static inline void update_load_avg(struct sched_entity *se, int update_tg)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
struct rq *rq = rq_of(cfs_rq);
int cpu = cpu_of(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);
if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg)
update_tg_load_avg(cfs_rq, 0);
if (cpu == smp_processor_id() && &rq->cfs == cfs_rq) {
unsigned long max = rq->cpu_capacity_orig;
@@ -2894,6 +2904,61 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
}
}
/* Group cfs_rq's load_avg is used for task_h_load and update_cfs_share */
static inline int
update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
{
struct sched_avg *sa = &cfs_rq->avg;
int decayed, removed_load = 0, removed_util = 0;
if (atomic_long_read(&cfs_rq->removed_load_avg)) {
s64 r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
sa->load_avg = max_t(long, sa->load_avg - r, 0);
sa->load_sum = max_t(s64, sa->load_sum - r * LOAD_AVG_MAX, 0);
removed_load = 1;
}
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, 0);
removed_util = 1;
}
decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
scale_load_down(cfs_rq->load.weight), cfs_rq->curr != NULL, cfs_rq);
#ifndef CONFIG_64BIT
smp_wmb();
cfs_rq->load_last_update_time_copy = sa->last_update_time;
#endif
if (update_freq && (decayed || removed_util))
cfs_rq_util_change(cfs_rq);
return decayed || removed_load;
}
/* Update task and its cfs_rq load average */
static inline void update_load_avg(struct sched_entity *se, int update_tg)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
struct rq *rq = rq_of(cfs_rq);
int cpu = cpu_of(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);
if (update_cfs_rq_load_avg(now, cfs_rq, true) && 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))
@@ -2919,6 +2984,8 @@ skip_aging:
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;
cfs_rq_util_change(cfs_rq);
}
static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -2931,6 +2998,8 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
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);
cfs_rq_util_change(cfs_rq);
}
/* Add the load generated by se into cfs_rq's load average */
@@ -2948,7 +3017,7 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->curr == se, NULL);
}
decayed = update_cfs_rq_load_avg(now, cfs_rq);
decayed = update_cfs_rq_load_avg(now, cfs_rq, !migrated);
cfs_rq->runnable_load_avg += sa->load_avg;
cfs_rq->runnable_load_sum += sa->load_sum;
@@ -3185,20 +3254,61 @@ static inline void check_schedstat_required(void)
#endif
}
/*
* MIGRATION
*
* dequeue
* update_curr()
* update_min_vruntime()
* vruntime -= min_vruntime
*
* enqueue
* update_curr()
* update_min_vruntime()
* vruntime += min_vruntime
*
* this way the vruntime transition between RQs is done when both
* min_vruntime are up-to-date.
*
* WAKEUP (remote)
*
* ->migrate_task_rq_fair() (p->state == TASK_WAKING)
* vruntime -= min_vruntime
*
* enqueue
* update_curr()
* update_min_vruntime()
* vruntime += min_vruntime
*
* this way we don't have the most up-to-date min_vruntime on the originating
* CPU and an up-to-date min_vruntime on the destination CPU.
*/
static void
enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
/*
* Update the normalized vruntime before updating min_vruntime
* through calling update_curr().
*/
if (!(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_WAKING))
se->vruntime += cfs_rq->min_vruntime;
bool renorm = !(flags & ENQUEUE_WAKEUP) || (flags & ENQUEUE_MIGRATED);
bool curr = cfs_rq->curr == se;
/*
* Update run-time statistics of the 'current'.
* If we're the current task, we must renormalise before calling
* update_curr().
*/
if (renorm && curr)
se->vruntime += cfs_rq->min_vruntime;
update_curr(cfs_rq);
/*
* Otherwise, renormalise after, such that we're placed at the current
* moment in time, instead of some random moment in the past. Being
* placed in the past could significantly boost this task to the
* fairness detriment of existing tasks.
*/
if (renorm && !curr)
se->vruntime += cfs_rq->min_vruntime;
enqueue_entity_load_avg(cfs_rq, se);
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
@@ -3214,7 +3324,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
update_stats_enqueue(cfs_rq, se);
check_spread(cfs_rq, se);
}
if (se != cfs_rq->curr)
if (!curr)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
@@ -4422,7 +4532,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
}
#ifdef CONFIG_SMP
#ifdef CONFIG_NO_HZ_COMMON
/*
* per rq 'load' arrray crap; XXX kill this.
*/
@@ -4488,13 +4598,13 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
}
return load;
}
#endif /* CONFIG_NO_HZ_COMMON */
/**
* __update_cpu_load - update the rq->cpu_load[] statistics
* __cpu_load_update - update the rq->cpu_load[] statistics
* @this_rq: The rq to update statistics for
* @this_load: The current load
* @pending_updates: The number of missed updates
* @active: !0 for NOHZ_FULL
*
* Update rq->cpu_load[] statistics. This function is usually called every
* scheduler tick (TICK_NSEC).
@@ -4523,12 +4633,12 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
* load[i]_n = (1 - 1/2^i)^n * load[i]_0
*
* see decay_load_misses(). For NOHZ_FULL we get to subtract and add the extra
* term. See the @active paramter.
* term.
*/
static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
unsigned long pending_updates, int active)
static void cpu_load_update(struct rq *this_rq, unsigned long this_load,
unsigned long pending_updates)
{
unsigned long tickless_load = active ? this_rq->cpu_load[0] : 0;
unsigned long __maybe_unused tickless_load = this_rq->cpu_load[0];
int i, scale;
this_rq->nr_load_updates++;
@@ -4541,6 +4651,7 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
/* scale is effectively 1 << i now, and >> i divides by scale */
old_load = this_rq->cpu_load[i];
#ifdef CONFIG_NO_HZ_COMMON
old_load = decay_load_missed(old_load, pending_updates - 1, i);
if (tickless_load) {
old_load -= decay_load_missed(tickless_load, pending_updates - 1, i);
@@ -4551,6 +4662,7 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
*/
old_load += tickless_load;
}
#endif
new_load = this_load;
/*
* Round up the averaging division if load is increasing. This
@@ -4573,10 +4685,23 @@ static unsigned long weighted_cpuload(const int cpu)
}
#ifdef CONFIG_NO_HZ_COMMON
static void __update_cpu_load_nohz(struct rq *this_rq,
unsigned long curr_jiffies,
unsigned long load,
int active)
/*
* There is no sane way to deal with nohz on smp when using jiffies because the
* cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
* causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
*
* Therefore we need to avoid the delta approach from the regular tick when
* possible since that would seriously skew the load calculation. This is why we
* use cpu_load_update_periodic() for CPUs out of nohz. However we'll rely on
* jiffies deltas for updates happening while in nohz mode (idle ticks, idle
* loop exit, nohz_idle_balance, nohz full exit...)
*
* This means we might still be one tick off for nohz periods.
*/
static void cpu_load_update_nohz(struct rq *this_rq,
unsigned long curr_jiffies,
unsigned long load)
{
unsigned long pending_updates;
@@ -4588,28 +4713,15 @@ static void __update_cpu_load_nohz(struct rq *this_rq,
* In the NOHZ_FULL case, we were non-idle, we should consider
* its weighted load.
*/
__update_cpu_load(this_rq, load, pending_updates, active);
cpu_load_update(this_rq, load, pending_updates);
}
}
/*
* There is no sane way to deal with nohz on smp when using jiffies because the
* cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
* causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
*
* Therefore we cannot use the delta approach from the regular tick since that
* would seriously skew the load calculation. However we'll make do for those
* updates happening while idle (nohz_idle_balance) or coming out of idle
* (tick_nohz_idle_exit).
*
* This means we might still be one tick off for nohz periods.
*/
/*
* Called from nohz_idle_balance() to update the load ratings before doing the
* idle balance.
*/
static void update_cpu_load_idle(struct rq *this_rq)
static void cpu_load_update_idle(struct rq *this_rq)
{
/*
* bail if there's load or we're actually up-to-date.
@@ -4617,38 +4729,71 @@ static void update_cpu_load_idle(struct rq *this_rq)
if (weighted_cpuload(cpu_of(this_rq)))
return;
__update_cpu_load_nohz(this_rq, READ_ONCE(jiffies), 0, 0);
cpu_load_update_nohz(this_rq, READ_ONCE(jiffies), 0);
}
/*
* Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed.
* Record CPU load on nohz entry so we know the tickless load to account
* on nohz exit. cpu_load[0] happens then to be updated more frequently
* than other cpu_load[idx] but it should be fine as cpu_load readers
* shouldn't rely into synchronized cpu_load[*] updates.
*/
void update_cpu_load_nohz(int active)
void cpu_load_update_nohz_start(void)
{
struct rq *this_rq = this_rq();
/*
* This is all lockless but should be fine. If weighted_cpuload changes
* concurrently we'll exit nohz. And cpu_load write can race with
* cpu_load_update_idle() but both updater would be writing the same.
*/
this_rq->cpu_load[0] = weighted_cpuload(cpu_of(this_rq));
}
/*
* Account the tickless load in the end of a nohz frame.
*/
void cpu_load_update_nohz_stop(void)
{
unsigned long curr_jiffies = READ_ONCE(jiffies);
unsigned long load = active ? weighted_cpuload(cpu_of(this_rq)) : 0;
struct rq *this_rq = this_rq();
unsigned long load;
if (curr_jiffies == this_rq->last_load_update_tick)
return;
load = weighted_cpuload(cpu_of(this_rq));
raw_spin_lock(&this_rq->lock);
__update_cpu_load_nohz(this_rq, curr_jiffies, load, active);
update_rq_clock(this_rq);
cpu_load_update_nohz(this_rq, curr_jiffies, load);
raw_spin_unlock(&this_rq->lock);
}
#endif /* CONFIG_NO_HZ */
#else /* !CONFIG_NO_HZ_COMMON */
static inline void cpu_load_update_nohz(struct rq *this_rq,
unsigned long curr_jiffies,
unsigned long load) { }
#endif /* CONFIG_NO_HZ_COMMON */
static void cpu_load_update_periodic(struct rq *this_rq, unsigned long load)
{
#ifdef CONFIG_NO_HZ_COMMON
/* See the mess around cpu_load_update_nohz(). */
this_rq->last_load_update_tick = READ_ONCE(jiffies);
#endif
cpu_load_update(this_rq, load, 1);
}
/*
* Called from scheduler_tick()
*/
void update_cpu_load_active(struct rq *this_rq)
void cpu_load_update_active(struct rq *this_rq)
{
unsigned long load = weighted_cpuload(cpu_of(this_rq));
/*
* See the mess around update_cpu_load_idle() / update_cpu_load_nohz().
*/
this_rq->last_load_update_tick = jiffies;
__update_cpu_load(this_rq, load, 1, 1);
if (tick_nohz_tick_stopped())
cpu_load_update_nohz(this_rq, READ_ONCE(jiffies), load);
else
cpu_load_update_periodic(this_rq, load);
}
/*
@@ -4706,46 +4851,6 @@ static unsigned long cpu_avg_load_per_task(int cpu)
return 0;
}
static void record_wakee(struct task_struct *p)
{
/*
* Rough decay (wiping) for cost saving, don't worry
* about the boundary, really active task won't care
* about the loss.
*/
if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) {
current->wakee_flips >>= 1;
current->wakee_flip_decay_ts = jiffies;
}
if (current->last_wakee != p) {
current->last_wakee = p;
current->wakee_flips++;
}
}
static void task_waking_fair(struct task_struct *p)
{
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 min_vruntime;
#ifndef CONFIG_64BIT
u64 min_vruntime_copy;
do {
min_vruntime_copy = cfs_rq->min_vruntime_copy;
smp_rmb();
min_vruntime = cfs_rq->min_vruntime;
} while (min_vruntime != min_vruntime_copy);
#else
min_vruntime = cfs_rq->min_vruntime;
#endif
se->vruntime -= min_vruntime;
record_wakee(p);
}
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
* effective_load() calculates the load change as seen from the root_task_group
@@ -4861,17 +4966,39 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
#endif
static void record_wakee(struct task_struct *p)
{
/*
* Only decay a single time; tasks that have less then 1 wakeup per
* jiffy will not have built up many flips.
*/
if (time_after(jiffies, current->wakee_flip_decay_ts + HZ)) {
current->wakee_flips >>= 1;
current->wakee_flip_decay_ts = jiffies;
}
if (current->last_wakee != p) {
current->last_wakee = p;
current->wakee_flips++;
}
}
/*
* Detect M:N waker/wakee relationships via a switching-frequency heuristic.
*
* A waker of many should wake a different task than the one last awakened
* at a frequency roughly N times higher than one of its wakees. In order
* to determine whether we should let the load spread vs consolodating to
* shared cache, we look for a minimum 'flip' frequency of llc_size in one
* partner, and a factor of lls_size higher frequency in the other. With
* both conditions met, we can be relatively sure that the relationship is
* non-monogamous, with partner count exceeding socket size. Waker/wakee
* being client/server, worker/dispatcher, interrupt source or whatever is
* irrelevant, spread criteria is apparent partner count exceeds socket size.
* at a frequency roughly N times higher than one of its wakees.
*
* In order to determine whether we should let the load spread vs consolidating
* to shared cache, we look for a minimum 'flip' frequency of llc_size in one
* partner, and a factor of lls_size higher frequency in the other.
*
* With both conditions met, we can be relatively sure that the relationship is
* non-monogamous, with partner count exceeding socket size.
*
* Waker/wakee being client/server, worker/dispatcher, interrupt source or
* whatever is irrelevant, spread criteria is apparent partner count exceeds
* socket size.
*/
static int wake_wide(struct task_struct *p)
{
@@ -5176,8 +5303,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
int want_affine = 0;
int sync = wake_flags & WF_SYNC;
if (sd_flag & SD_BALANCE_WAKE)
if (sd_flag & SD_BALANCE_WAKE) {
record_wakee(p);
want_affine = !wake_wide(p) && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
}
rcu_read_lock();
for_each_domain(cpu, tmp) {
@@ -5256,6 +5385,32 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
*/
static void migrate_task_rq_fair(struct task_struct *p)
{
/*
* As blocked tasks retain absolute vruntime the migration needs to
* deal with this by subtracting the old and adding the new
* min_vruntime -- the latter is done by enqueue_entity() when placing
* the task on the new runqueue.
*/
if (p->state == TASK_WAKING) {
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 min_vruntime;
#ifndef CONFIG_64BIT
u64 min_vruntime_copy;
do {
min_vruntime_copy = cfs_rq->min_vruntime_copy;
smp_rmb();
min_vruntime = cfs_rq->min_vruntime;
} while (min_vruntime != min_vruntime_copy);
#else
min_vruntime = cfs_rq->min_vruntime;
#endif
se->vruntime -= min_vruntime;
}
/*
* We are supposed to update the task to "current" time, then its up to date
* and ready to go to new CPU/cfs_rq. But we have difficulty in getting
@@ -5439,7 +5594,7 @@ preempt:
}
static struct task_struct *
pick_next_task_fair(struct rq *rq, struct task_struct *prev)
pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct cfs_rq *cfs_rq = &rq->cfs;
struct sched_entity *se;
@@ -5552,9 +5707,9 @@ idle:
* further scheduler activity on it and we're being very careful to
* re-start the picking loop.
*/
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, cookie);
new_tasks = idle_balance(rq);
lockdep_pin_lock(&rq->lock);
lockdep_repin_lock(&rq->lock, cookie);
/*
* Because idle_balance() releases (and re-acquires) rq->lock, it is
* possible for any higher priority task to appear. In that case we
@@ -5653,7 +5808,7 @@ static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preemp
* W_i,0 = \Sum_j w_i,j (2)
*
* Where w_i,j is the weight of the j-th runnable task on cpu i. This weight
* is derived from the nice value as per prio_to_weight[].
* is derived from the nice value as per sched_prio_to_weight[].
*
* The weight average is an exponential decay average of the instantaneous
* weight:
@@ -6155,7 +6310,7 @@ static void update_blocked_averages(int cpu)
if (throttled_hierarchy(cfs_rq))
continue;
if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq))
if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true))
update_tg_load_avg(cfs_rq, 0);
}
raw_spin_unlock_irqrestore(&rq->lock, flags);
@@ -6216,7 +6371,7 @@ static inline void update_blocked_averages(int cpu)
raw_spin_lock_irqsave(&rq->lock, flags);
update_rq_clock(rq);
update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq);
update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true);
raw_spin_unlock_irqrestore(&rq->lock, flags);
}
@@ -6625,6 +6780,9 @@ static bool update_sd_pick_busiest(struct lb_env *env,
if (!(env->sd->flags & SD_ASYM_PACKING))
return true;
/* No ASYM_PACKING if target cpu is already busy */
if (env->idle == CPU_NOT_IDLE)
return true;
/*
* ASYM_PACKING needs to move all the work to the lowest
* numbered CPUs in the group, therefore mark all groups
@@ -6634,7 +6792,8 @@ static bool update_sd_pick_busiest(struct lb_env *env,
if (!sds->busiest)
return true;
if (group_first_cpu(sds->busiest) > group_first_cpu(sg))
/* Prefer to move from highest possible cpu's work */
if (group_first_cpu(sds->busiest) < group_first_cpu(sg))
return true;
}
@@ -6780,6 +6939,9 @@ static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds)
if (!(env->sd->flags & SD_ASYM_PACKING))
return 0;
if (env->idle == CPU_NOT_IDLE)
return 0;
if (!sds->busiest)
return 0;
@@ -6888,9 +7050,10 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
}
/*
* In the presence of smp nice balancing, certain scenarios can have
* max load less than avg load(as we skip the groups at or below
* its cpu_capacity, while calculating max_load..)
* Avg load of busiest sg can be less and avg load of local sg can
* be greater than avg load across all sgs of sd because avg load
* factors in sg capacity and sgs with smaller group_type are
* skipped when updating the busiest sg:
*/
if (busiest->avg_load <= sds->avg_load ||
local->avg_load >= sds->avg_load) {
@@ -6903,11 +7066,12 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
*/
if (busiest->group_type == group_overloaded &&
local->group_type == group_overloaded) {
load_above_capacity = busiest->sum_nr_running *
SCHED_LOAD_SCALE;
if (load_above_capacity > busiest->group_capacity)
load_above_capacity = busiest->sum_nr_running * SCHED_CAPACITY_SCALE;
if (load_above_capacity > busiest->group_capacity) {
load_above_capacity -= busiest->group_capacity;
else
load_above_capacity *= NICE_0_LOAD;
load_above_capacity /= busiest->group_capacity;
} else
load_above_capacity = ~0UL;
}
@@ -6915,9 +7079,8 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* We're trying to get all the cpus to the average_load, so we don't
* want to push ourselves above the average load, nor do we wish to
* reduce the max loaded cpu below the average load. At the same time,
* we also don't want to reduce the group load below the group capacity
* (so that we can implement power-savings policies etc). Thus we look
* for the minimum possible imbalance.
* we also don't want to reduce the group load below the group
* capacity. Thus we look for the minimum possible imbalance.
*/
max_pull = min(busiest->avg_load - sds->avg_load, load_above_capacity);
@@ -6941,10 +7104,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
/**
* find_busiest_group - Returns the busiest group within the sched_domain
* if there is an imbalance. If there isn't an imbalance, and
* the user has opted for power-savings, it returns a group whose
* CPUs can be put to idle by rebalancing those tasks elsewhere, if
* such a group exists.
* if there is an imbalance.
*
* Also calculates the amount of weighted load which should be moved
* to restore balance.
@@ -6952,9 +7112,6 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
* @env: The load balancing environment.
*
* Return: - The busiest group if imbalance exists.
* - If no imbalance and user has opted for power-savings balance,
* return the least loaded group whose CPUs can be
* put to idle by rebalancing its tasks onto our group.
*/
static struct sched_group *find_busiest_group(struct lb_env *env)
{
@@ -6972,8 +7129,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
busiest = &sds.busiest_stat;
/* ASYM feature bypasses nice load balance check */
if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) &&
check_asym_packing(env, &sds))
if (check_asym_packing(env, &sds))
return sds.busiest;
/* There is no busy sibling group to pull tasks from */
@@ -7398,10 +7554,7 @@ more_balance:
&busiest->active_balance_work);
}
/*
* We've kicked active balancing, reset the failure
* counter.
*/
/* We've kicked active balancing, force task migration. */
sd->nr_balance_failed = sd->cache_nice_tries+1;
}
} else
@@ -7636,10 +7789,13 @@ static int active_load_balance_cpu_stop(void *data)
schedstat_inc(sd, alb_count);
p = detach_one_task(&env);
if (p)
if (p) {
schedstat_inc(sd, alb_pushed);
else
/* Active balancing done, reset the failure counter. */
sd->nr_balance_failed = 0;
} else {
schedstat_inc(sd, alb_failed);
}
}
rcu_read_unlock();
out_unlock:
@@ -7710,7 +7866,7 @@ static void nohz_balancer_kick(void)
return;
}
static inline void nohz_balance_exit_idle(int cpu)
void nohz_balance_exit_idle(unsigned int cpu)
{
if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
/*
@@ -7783,18 +7939,6 @@ void nohz_balance_enter_idle(int cpu)
atomic_inc(&nohz.nr_cpus);
set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
}
static int sched_ilb_notifier(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DYING:
nohz_balance_exit_idle(smp_processor_id());
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}
#endif
static DEFINE_SPINLOCK(balancing);
@@ -7956,7 +8100,7 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle)
if (time_after_eq(jiffies, rq->next_balance)) {
raw_spin_lock_irq(&rq->lock);
update_rq_clock(rq);
update_cpu_load_idle(rq);
cpu_load_update_idle(rq);
raw_spin_unlock_irq(&rq->lock);
rebalance_domains(rq, CPU_IDLE);
}
@@ -8381,6 +8525,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
init_cfs_rq(cfs_rq);
init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
init_entity_runnable_average(se);
post_init_entity_util_avg(se);
}
return 1;
@@ -8537,7 +8682,6 @@ const struct sched_class fair_sched_class = {
.rq_online = rq_online_fair,
.rq_offline = rq_offline_fair,
.task_waking = task_waking_fair,
.task_dead = task_dead_fair,
.set_cpus_allowed = set_cpus_allowed_common,
#endif
@@ -8599,7 +8743,6 @@ __init void init_sched_fair_class(void)
#ifdef CONFIG_NO_HZ_COMMON
nohz.next_balance = jiffies;
zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
cpu_notifier(sched_ilb_notifier, 0);
#endif
#endif /* SMP */

2
kernel/sched/idle_task.c
View File

@@ -24,7 +24,7 @@ static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int fl
}
static struct task_struct *
pick_next_task_idle(struct rq *rq, struct task_struct *prev)
pick_next_task_idle(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
put_prev_task(rq, prev);

11
kernel/sched/loadavg.c
View File

@@ -99,10 +99,13 @@ long calc_load_fold_active(struct rq *this_rq)
static unsigned long
calc_load(unsigned long load, unsigned long exp, unsigned long active)
{
load *= exp;
load += active * (FIXED_1 - exp);
load += 1UL << (FSHIFT - 1);
return load >> FSHIFT;
unsigned long newload;
newload = load * exp + active * (FIXED_1 - exp);
if (active >= load)
newload += FIXED_1-1;
return newload / FIXED_1;
}
#ifdef CONFIG_NO_HZ_COMMON

38
kernel/sched/rt.c
View File

@@ -334,7 +334,7 @@ static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total++;
if (p->nr_cpus_allowed > 1)
if (tsk_nr_cpus_allowed(p) > 1)
rt_rq->rt_nr_migratory++;
update_rt_migration(rt_rq);
@@ -351,7 +351,7 @@ static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total--;
if (p->nr_cpus_allowed > 1)
if (tsk_nr_cpus_allowed(p) > 1)
rt_rq->rt_nr_migratory--;
update_rt_migration(rt_rq);
@@ -953,14 +953,14 @@ static void update_curr_rt(struct rq *rq)
if (curr->sched_class != &rt_sched_class)
return;
/* Kick cpufreq (see the comment in linux/cpufreq.h). */
if (cpu_of(rq) == smp_processor_id())
cpufreq_trigger_update(rq_clock(rq));
delta_exec = rq_clock_task(rq) - curr->se.exec_start;
if (unlikely((s64)delta_exec <= 0))
return;
/* Kick cpufreq (see the comment in linux/cpufreq.h). */
if (cpu_of(rq) == smp_processor_id())
cpufreq_trigger_update(rq_clock(rq));
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));
@@ -1324,7 +1324,7 @@ enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
enqueue_rt_entity(rt_se, flags);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
if (!task_current(rq, p) && tsk_nr_cpus_allowed(p) > 1)
enqueue_pushable_task(rq, p);
}
@@ -1413,7 +1413,7 @@ select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags)
* will have to sort it out.
*/
if (curr && unlikely(rt_task(curr)) &&
(curr->nr_cpus_allowed < 2 ||
(tsk_nr_cpus_allowed(curr) < 2 ||
curr->prio <= p->prio)) {
int target = find_lowest_rq(p);
@@ -1437,7 +1437,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
* Current can't be migrated, useless to reschedule,
* let's hope p can move out.
*/
if (rq->curr->nr_cpus_allowed == 1 ||
if (tsk_nr_cpus_allowed(rq->curr) == 1 ||
!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
return;
@@ -1445,7 +1445,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
* p is migratable, so let's not schedule it and
* see if it is pushed or pulled somewhere else.
*/
if (p->nr_cpus_allowed != 1
if (tsk_nr_cpus_allowed(p) != 1
&& cpupri_find(&rq->rd->cpupri, p, NULL))
return;
@@ -1524,7 +1524,7 @@ static struct task_struct *_pick_next_task_rt(struct rq *rq)
}
static struct task_struct *
pick_next_task_rt(struct rq *rq, struct task_struct *prev)
pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct task_struct *p;
struct rt_rq *rt_rq = &rq->rt;
@@ -1536,9 +1536,9 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev)
* disabled avoiding further scheduler activity on it and we're
* being very careful to re-start the picking loop.
*/
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, cookie);
pull_rt_task(rq);
lockdep_pin_lock(&rq->lock);
lockdep_repin_lock(&rq->lock, cookie);
/*
* pull_rt_task() can drop (and re-acquire) rq->lock; this
* means a dl or stop task can slip in, in which case we need
@@ -1579,7 +1579,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
* The previous task needs to be made eligible for pushing
* if it is still active
*/
if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
if (on_rt_rq(&p->rt) && tsk_nr_cpus_allowed(p) > 1)
enqueue_pushable_task(rq, p);
}
@@ -1629,7 +1629,7 @@ static int find_lowest_rq(struct task_struct *task)
if (unlikely(!lowest_mask))
return -1;
if (task->nr_cpus_allowed == 1)
if (tsk_nr_cpus_allowed(task) == 1)
return -1; /* No other targets possible */
if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
@@ -1762,7 +1762,7 @@ static struct task_struct *pick_next_pushable_task(struct rq *rq)
BUG_ON(rq->cpu != task_cpu(p));
BUG_ON(task_current(rq, p));
BUG_ON(p->nr_cpus_allowed <= 1);
BUG_ON(tsk_nr_cpus_allowed(p) <= 1);
BUG_ON(!task_on_rq_queued(p));
BUG_ON(!rt_task(p));
@@ -2122,9 +2122,9 @@ static void task_woken_rt(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
p->nr_cpus_allowed > 1 &&
tsk_nr_cpus_allowed(p) > 1 &&
(dl_task(rq->curr) || rt_task(rq->curr)) &&
(rq->curr->nr_cpus_allowed < 2 ||
(tsk_nr_cpus_allowed(rq->curr) < 2 ||
rq->curr->prio <= p->prio))
push_rt_tasks(rq);
}
@@ -2197,7 +2197,7 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p)
*/
if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
if (tsk_nr_cpus_allowed(p) > 1 && rq->rt.overloaded)
queue_push_tasks(rq);
#else
if (p->prio < rq->curr->prio)

140
kernel/sched/sched.h
View File

@@ -31,9 +31,9 @@ extern void calc_global_load_tick(struct rq *this_rq);
extern long calc_load_fold_active(struct rq *this_rq);
#ifdef CONFIG_SMP
extern void update_cpu_load_active(struct rq *this_rq);
extern void cpu_load_update_active(struct rq *this_rq);
#else
static inline void update_cpu_load_active(struct rq *this_rq) { }
static inline void cpu_load_update_active(struct rq *this_rq) { }
#endif
/*
@@ -49,25 +49,32 @@ static inline void update_cpu_load_active(struct rq *this_rq) { }
* and does not change the user-interface for setting shares/weights.
*
* We increase resolution only if we have enough bits to allow this increased
* resolution (i.e. BITS_PER_LONG > 32). The costs for increasing resolution
* when BITS_PER_LONG <= 32 are pretty high and the returns do not justify the
* increased costs.
* resolution (i.e. 64bit). The costs for increasing resolution when 32bit are
* pretty high and the returns do not justify the increased costs.
*
* Really only required when CONFIG_FAIR_GROUP_SCHED is also set, but to
* increase coverage and consistency always enable it on 64bit platforms.
*/
#if 0 /* BITS_PER_LONG > 32 -- currently broken: it increases power usage under light load */
# define SCHED_LOAD_RESOLUTION 10
# define scale_load(w) ((w) << SCHED_LOAD_RESOLUTION)
# define scale_load_down(w) ((w) >> SCHED_LOAD_RESOLUTION)
#ifdef CONFIG_64BIT
# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w) ((w) << SCHED_FIXEDPOINT_SHIFT)
# define scale_load_down(w) ((w) >> SCHED_FIXEDPOINT_SHIFT)
#else
# define SCHED_LOAD_RESOLUTION 0
# define NICE_0_LOAD_SHIFT (SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w) (w)
# define scale_load_down(w) (w)
#endif
#define SCHED_LOAD_SHIFT (10 + SCHED_LOAD_RESOLUTION)
#define SCHED_LOAD_SCALE (1L << SCHED_LOAD_SHIFT)
#define NICE_0_LOAD SCHED_LOAD_SCALE
#define NICE_0_SHIFT SCHED_LOAD_SHIFT
/*
* Task weight (visible to users) and its load (invisible to users) have
* independent resolution, but they should be well calibrated. We use
* scale_load() and scale_load_down(w) to convert between them. The
* following must be true:
*
* scale_load(sched_prio_to_weight[USER_PRIO(NICE_TO_PRIO(0))]) == NICE_0_LOAD
*
*/
#define NICE_0_LOAD (1L << NICE_0_LOAD_SHIFT)
/*
* Single value that decides SCHED_DEADLINE internal math precision.
@@ -585,11 +592,13 @@ struct rq {
#endif
#define CPU_LOAD_IDX_MAX 5
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
unsigned long last_load_update_tick;
#ifdef CONFIG_NO_HZ_COMMON
#ifdef CONFIG_SMP
unsigned long last_load_update_tick;
#endif /* CONFIG_SMP */
u64 nohz_stamp;
unsigned long nohz_flags;
#endif
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
unsigned long last_sched_tick;
#endif
@@ -854,7 +863,7 @@ DECLARE_PER_CPU(struct sched_domain *, sd_asym);
struct sched_group_capacity {
atomic_t ref;
/*
* CPU capacity of this group, SCHED_LOAD_SCALE being max capacity
* CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
* for a single CPU.
*/
unsigned int capacity;
@@ -1159,7 +1168,7 @@ extern const u32 sched_prio_to_wmult[40];
*
* ENQUEUE_HEAD - place at front of runqueue (tail if not specified)
* ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
* ENQUEUE_WAKING - sched_class::task_waking was called
* ENQUEUE_MIGRATED - the task was migrated during wakeup
*
*/
@@ -1174,9 +1183,9 @@ extern const u32 sched_prio_to_wmult[40];
#define ENQUEUE_HEAD 0x08
#define ENQUEUE_REPLENISH 0x10
#ifdef CONFIG_SMP
#define ENQUEUE_WAKING 0x20
#define ENQUEUE_MIGRATED 0x20
#else
#define ENQUEUE_WAKING 0x00
#define ENQUEUE_MIGRATED 0x00
#endif
#define RETRY_TASK ((void *)-1UL)
@@ -1200,14 +1209,14 @@ struct sched_class {
* tasks.
*/
struct task_struct * (*pick_next_task) (struct rq *rq,
struct task_struct *prev);
struct task_struct *prev,
struct pin_cookie cookie);
void (*put_prev_task) (struct rq *rq, struct task_struct *p);
#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);
void (*task_waking) (struct task_struct *task);
void (*task_woken) (struct rq *this_rq, struct task_struct *task);
void (*set_cpus_allowed)(struct task_struct *p,
@@ -1313,6 +1322,7 @@ extern void init_dl_task_timer(struct sched_dl_entity *dl_se);
unsigned long to_ratio(u64 period, u64 runtime);
extern void init_entity_runnable_average(struct sched_entity *se);
extern void post_init_entity_util_avg(struct sched_entity *se);
#ifdef CONFIG_NO_HZ_FULL
extern bool sched_can_stop_tick(struct rq *rq);
@@ -1448,86 +1458,32 @@ static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
static inline void sched_avg_update(struct rq *rq) { }
#endif
/*
* __task_rq_lock - lock the rq @p resides on.
*/
static inline struct rq *__task_rq_lock(struct task_struct *p)
__acquires(rq->lock)
{
struct rq *rq;
struct rq_flags {
unsigned long flags;
struct pin_cookie cookie;
};
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))) {
lockdep_pin_lock(&rq->lock);
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.
*/
static inline struct rq *task_rq_lock(struct task_struct *p, 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)
{
struct rq *rq;
__acquires(rq->lock);
for (;;) {
raw_spin_lock_irqsave(&p->pi_lock, *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 acquire will
* pair with the WMB to ensure we must then also see migrating.
*/
if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
lockdep_pin_lock(&rq->lock);
return rq;
}
raw_spin_unlock(&rq->lock);
raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
while (unlikely(task_on_rq_migrating(p)))
cpu_relax();
}
}
static inline void __task_rq_unlock(struct rq *rq)
static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
__releases(rq->lock)
{
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, rf->cookie);
raw_spin_unlock(&rq->lock);
}
static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
__releases(rq->lock)
__releases(p->pi_lock)
{
lockdep_unpin_lock(&rq->lock);
lockdep_unpin_lock(&rq->lock, rf->cookie);
raw_spin_unlock(&rq->lock);
raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
}
#ifdef CONFIG_SMP
@@ -1743,6 +1699,10 @@ enum rq_nohz_flag_bits {
};
#define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)
extern void nohz_balance_exit_idle(unsigned int cpu);
#else
static inline void nohz_balance_exit_idle(unsigned int cpu) { }
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING

2
kernel/sched/stop_task.c
View File

@@ -24,7 +24,7 @@ check_preempt_curr_stop(struct rq *rq, struct task_struct *p, int flags)
}
static struct task_struct *
pick_next_task_stop(struct rq *rq, struct task_struct *prev)
pick_next_task_stop(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie)
{
struct task_struct *stop = rq->stop;

9
kernel/time/tick-sched.c
View File

@@ -776,6 +776,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
if (!ts->tick_stopped) {
nohz_balance_enter_idle(cpu);
calc_load_enter_idle();
cpu_load_update_nohz_start();
ts->last_tick = hrtimer_get_expires(&ts->sched_timer);
ts->tick_stopped = 1;
@@ -802,11 +803,11 @@ out:
return tick;
}
static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now, int active)
static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
{
/* Update jiffies first */
tick_do_update_jiffies64(now);
update_cpu_load_nohz(active);
cpu_load_update_nohz_stop();
calc_load_exit_idle();
touch_softlockup_watchdog_sched();
@@ -833,7 +834,7 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
if (can_stop_full_tick(ts))
tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
else if (ts->tick_stopped)
tick_nohz_restart_sched_tick(ts, ktime_get(), 1);
tick_nohz_restart_sched_tick(ts, ktime_get());
#endif
}
@@ -1024,7 +1025,7 @@ void tick_nohz_idle_exit(void)
tick_nohz_stop_idle(ts, now);
if (ts->tick_stopped) {
tick_nohz_restart_sched_tick(ts, now, 0);
tick_nohz_restart_sched_tick(ts, now);
tick_nohz_account_idle_ticks(ts);
}