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Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

Browse Source 
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (37 commits)
  sched: Fix SD_POWERSAVING_BALANCE|SD_PREFER_LOCAL vs SD_WAKE_AFFINE
  sched: Stop buddies from hogging the system
  sched: Add new wakeup preemption mode: WAKEUP_RUNNING
  sched: Fix TASK_WAKING & loadaverage breakage
  sched: Disable wakeup balancing
  sched: Rename flags to wake_flags
  sched: Clean up the load_idx selection in select_task_rq_fair
  sched: Optimize cgroup vs wakeup a bit
  sched: x86: Name old_perf in a unique way
  sched: Implement a gentler fair-sleepers feature
  sched: Add SD_PREFER_LOCAL
  sched: Add a few SYNC hint knobs to play with
  sched: Fix sync wakeups again
  sched: Add WF_FORK
  sched: Rename sync arguments
  sched: Rename select_task_rq() argument
  sched: Feature to disable APERF/MPERF cpu_power
  x86: sched: Provide arch implementations using aperf/mperf
  x86: Add generic aperf/mperf code
  x86: Move APERF/MPERF into a X86_FEATURE
  ...

Fix up trivial conflict in arch/x86/include/asm/processor.h due to
nearby addition of amd_get_nb_id() declaration from the EDAC merge.
This commit is contained in:
Linus Torvalds
2009-09-17 21:00:02 -07:00
parent ca043a66ae 29cd8bae39
commit dcbf77b9e8
21 changed files with 691 additions and 606 deletions
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446
kernel/sched.c
View File

@@ -119,8 +119,6 @@
*/
#define RUNTIME_INF ((u64)~0ULL)
static void double_rq_lock(struct rq *rq1, struct rq *rq2);
static inline int rt_policy(int policy)
{
if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
@@ -378,13 +376,6 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#else
#ifdef CONFIG_SMP
static int root_task_group_empty(void)
{
return 1;
}
#endif
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
@@ -514,14 +505,6 @@ struct root_domain {
#ifdef CONFIG_SMP
struct cpupri cpupri;
#endif
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
/*
* Preferred wake up cpu nominated by sched_mc balance that will be
* used when most cpus are idle in the system indicating overall very
* low system utilisation. Triggered at POWERSAVINGS_BALANCE_WAKEUP(2)
*/
unsigned int sched_mc_preferred_wakeup_cpu;
#endif
};
/*
@@ -646,9 +629,10 @@ struct rq {
static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
static inline void check_preempt_curr(struct rq *rq, struct task_struct *p, int sync)
static inline
void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
{
rq->curr->sched_class->check_preempt_curr(rq, p, sync);
rq->curr->sched_class->check_preempt_curr(rq, p, flags);
}
static inline int cpu_of(struct rq *rq)
@@ -1509,8 +1493,65 @@ static int tg_nop(struct task_group *tg, void *data)
#endif
#ifdef CONFIG_SMP
static unsigned long source_load(int cpu, int type);
static unsigned long target_load(int cpu, int type);
/* Used instead of source_load when we know the type == 0 */
static unsigned long weighted_cpuload(const int cpu)
{
return cpu_rq(cpu)->load.weight;
}
/*
* Return a low guess at the load of a migration-source cpu weighted
* according to the scheduling class and "nice" value.
*
* We want to under-estimate the load of migration sources, to
* balance conservatively.
*/
static unsigned long source_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
unsigned long total = weighted_cpuload(cpu);
if (type == 0 || !sched_feat(LB_BIAS))
return total;
return min(rq->cpu_load[type-1], total);
}
/*
* Return a high guess at the load of a migration-target cpu weighted
* according to the scheduling class and "nice" value.
*/
static unsigned long target_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
unsigned long total = weighted_cpuload(cpu);
if (type == 0 || !sched_feat(LB_BIAS))
return total;
return max(rq->cpu_load[type-1], total);
}
static struct sched_group *group_of(int cpu)
{
struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd);
if (!sd)
return NULL;
return sd->groups;
}
static unsigned long power_of(int cpu)
{
struct sched_group *group = group_of(cpu);
if (!group)
return SCHED_LOAD_SCALE;
return group->cpu_power;
}
static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
static unsigned long cpu_avg_load_per_task(int cpu)
@@ -1695,6 +1736,8 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
#ifdef CONFIG_PREEMPT
static void double_rq_lock(struct rq *rq1, struct rq *rq2);
/*
* fair double_lock_balance: Safely acquires both rq->locks in a fair
* way at the expense of forcing extra atomic operations in all
@@ -1959,13 +2002,6 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p,
}
#ifdef CONFIG_SMP
/* Used instead of source_load when we know the type == 0 */
static unsigned long weighted_cpuload(const int cpu)
{
return cpu_rq(cpu)->load.weight;
}
/*
* Is this task likely cache-hot:
*/
@@ -2239,185 +2275,6 @@ void kick_process(struct task_struct *p)
preempt_enable();
}
EXPORT_SYMBOL_GPL(kick_process);
/*
* Return a low guess at the load of a migration-source cpu weighted
* according to the scheduling class and "nice" value.
*
* We want to under-estimate the load of migration sources, to
* balance conservatively.
*/
static unsigned long source_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
unsigned long total = weighted_cpuload(cpu);
if (type == 0 || !sched_feat(LB_BIAS))
return total;
return min(rq->cpu_load[type-1], total);
}
/*
* Return a high guess at the load of a migration-target cpu weighted
* according to the scheduling class and "nice" value.
*/
static unsigned long target_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
unsigned long total = weighted_cpuload(cpu);
if (type == 0 || !sched_feat(LB_BIAS))
return total;
return max(rq->cpu_load[type-1], total);
}
/*
* find_idlest_group finds and returns the least busy CPU group within the
* domain.
*/
static struct sched_group *
find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
{
struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
unsigned long min_load = ULONG_MAX, this_load = 0;
int load_idx = sd->forkexec_idx;
int imbalance = 100 + (sd->imbalance_pct-100)/2;
do {
unsigned long load, avg_load;
int local_group;
int i;
/* Skip over this group if it has no CPUs allowed */
if (!cpumask_intersects(sched_group_cpus(group),
&p->cpus_allowed))
continue;
local_group = cpumask_test_cpu(this_cpu,
sched_group_cpus(group));
/* Tally up the load of all CPUs in the group */
avg_load = 0;
for_each_cpu(i, sched_group_cpus(group)) {
/* Bias balancing toward cpus of our domain */
if (local_group)
load = source_load(i, load_idx);
else
load = target_load(i, load_idx);
avg_load += load;
}
/* Adjust by relative CPU power of the group */
avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
if (local_group) {
this_load = avg_load;
this = group;
} else if (avg_load < min_load) {
min_load = avg_load;
idlest = group;
}
} while (group = group->next, group != sd->groups);
if (!idlest || 100*this_load < imbalance*min_load)
return NULL;
return idlest;
}
/*
* find_idlest_cpu - find the idlest cpu among the cpus in group.
*/
static int
find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
{
unsigned long load, min_load = ULONG_MAX;
int idlest = -1;
int i;
/* Traverse only the allowed CPUs */
for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
load = weighted_cpuload(i);
if (load < min_load || (load == min_load && i == this_cpu)) {
min_load = load;
idlest = i;
}
}
return idlest;
}
/*
* sched_balance_self: balance the current task (running on cpu) in domains
* that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
* SD_BALANCE_EXEC.
*
* Balance, ie. select the least loaded group.
*
* Returns the target CPU number, or the same CPU if no balancing is needed.
*
* preempt must be disabled.
*/
static int sched_balance_self(int cpu, int flag)
{
struct task_struct *t = current;
struct sched_domain *tmp, *sd = NULL;
for_each_domain(cpu, tmp) {
/*
* If power savings logic is enabled for a domain, stop there.
*/
if (tmp->flags & SD_POWERSAVINGS_BALANCE)
break;
if (tmp->flags & flag)
sd = tmp;
}
if (sd)
update_shares(sd);
while (sd) {
struct sched_group *group;
int new_cpu, weight;
if (!(sd->flags & flag)) {
sd = sd->child;
continue;
}
group = find_idlest_group(sd, t, cpu);
if (!group) {
sd = sd->child;
continue;
}
new_cpu = find_idlest_cpu(group, t, cpu);
if (new_cpu == -1 || new_cpu == cpu) {
/* Now try balancing at a lower domain level of cpu */
sd = sd->child;
continue;
}
/* Now try balancing at a lower domain level of new_cpu */
cpu = new_cpu;
weight = cpumask_weight(sched_domain_span(sd));
sd = NULL;
for_each_domain(cpu, tmp) {
if (weight <= cpumask_weight(sched_domain_span(tmp)))
break;
if (tmp->flags & flag)
sd = tmp;
}
/* while loop will break here if sd == NULL */
}
return cpu;
}
#endif /* CONFIG_SMP */
/**
@@ -2455,37 +2312,22 @@ void task_oncpu_function_call(struct task_struct *p,
*
* returns failure only if the task is already active.
*/
static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
static int try_to_wake_up(struct task_struct *p, unsigned int state,
int wake_flags)
{
int cpu, orig_cpu, this_cpu, success = 0;
unsigned long flags;
long old_state;
struct rq *rq;
if (!sched_feat(SYNC_WAKEUPS))
sync = 0;
wake_flags &= ~WF_SYNC;
#ifdef CONFIG_SMP
if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
struct sched_domain *sd;
this_cpu = raw_smp_processor_id();
cpu = task_cpu(p);
for_each_domain(this_cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
update_shares(sd);
break;
}
}
}
#endif
this_cpu = get_cpu();
smp_wmb();
rq = task_rq_lock(p, &flags);
update_rq_clock(rq);
old_state = p->state;
if (!(old_state & state))
if (!(p->state & state))
goto out;
if (p->se.on_rq)
@@ -2493,27 +2335,29 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
cpu = task_cpu(p);
orig_cpu = cpu;
this_cpu = smp_processor_id();
#ifdef CONFIG_SMP
if (unlikely(task_running(rq, p)))
goto out_activate;
cpu = p->sched_class->select_task_rq(p, sync);
if (cpu != orig_cpu) {
set_task_cpu(p, cpu);
task_rq_unlock(rq, &flags);
/* might preempt at this point */
rq = task_rq_lock(p, &flags);
old_state = p->state;
if (!(old_state & state))
goto out;
if (p->se.on_rq)
goto out_running;
/*
* In order to handle concurrent wakeups and release the rq->lock
* we put the task in TASK_WAKING state.
*
* First fix up the nr_uninterruptible count:
*/
if (task_contributes_to_load(p))
rq->nr_uninterruptible--;
p->state = TASK_WAKING;
task_rq_unlock(rq, &flags);
this_cpu = smp_processor_id();
cpu = task_cpu(p);
}
cpu = p->sched_class->select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
if (cpu != orig_cpu)
set_task_cpu(p, cpu);
rq = task_rq_lock(p, &flags);
WARN_ON(p->state != TASK_WAKING);
cpu = task_cpu(p);
#ifdef CONFIG_SCHEDSTATS
schedstat_inc(rq, ttwu_count);
@@ -2533,7 +2377,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
out_activate:
#endif /* CONFIG_SMP */
schedstat_inc(p, se.nr_wakeups);
if (sync)
if (wake_flags & WF_SYNC)
schedstat_inc(p, se.nr_wakeups_sync);
if (orig_cpu != cpu)
schedstat_inc(p, se.nr_wakeups_migrate);
@@ -2562,7 +2406,7 @@ out_activate:
out_running:
trace_sched_wakeup(rq, p, success);
check_preempt_curr(rq, p, sync);
check_preempt_curr(rq, p, wake_flags);
p->state = TASK_RUNNING;
#ifdef CONFIG_SMP
@@ -2571,6 +2415,7 @@ out_running:
#endif
out:
task_rq_unlock(rq, &flags);
put_cpu();
return success;
}
@@ -2613,6 +2458,7 @@ static void __sched_fork(struct task_struct *p)
p->se.avg_overlap = 0;
p->se.start_runtime = 0;
p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
p->se.avg_running = 0;
#ifdef CONFIG_SCHEDSTATS
p->se.wait_start = 0;
@@ -2674,11 +2520,6 @@ void sched_fork(struct task_struct *p, int clone_flags)
__sched_fork(p);
#ifdef CONFIG_SMP
cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
#endif
set_task_cpu(p, cpu);
/*
* Make sure we do not leak PI boosting priority to the child.
*/
@@ -2709,6 +2550,11 @@ void sched_fork(struct task_struct *p, int clone_flags)
if (!rt_prio(p->prio))
p->sched_class = &fair_sched_class;
#ifdef CONFIG_SMP
cpu = p->sched_class->select_task_rq(p, SD_BALANCE_FORK, 0);
#endif
set_task_cpu(p, cpu);
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
if (likely(sched_info_on()))
memset(&p->sched_info, 0, sizeof(p->sched_info));
@@ -2754,7 +2600,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
inc_nr_running(rq);
}
trace_sched_wakeup_new(rq, p, 1);
check_preempt_curr(rq, p, 0);
check_preempt_curr(rq, p, WF_FORK);
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
p->sched_class->task_wake_up(rq, p);
@@ -3263,7 +3109,7 @@ out:
void sched_exec(void)
{
int new_cpu, this_cpu = get_cpu();
new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
new_cpu = current->sched_class->select_task_rq(current, SD_BALANCE_EXEC, 0);
put_cpu();
if (new_cpu != this_cpu)
sched_migrate_task(current, new_cpu);
@@ -3683,11 +3529,6 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
*imbalance = sds->min_load_per_task;
sds->busiest = sds->group_min;
if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
group_first_cpu(sds->group_leader);
}
return 1;
}
@@ -3711,7 +3552,18 @@ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
{
return SCHED_LOAD_SCALE;
}
unsigned long __weak arch_scale_freq_power(struct sched_domain *sd, int cpu)
{
return default_scale_freq_power(sd, cpu);
}
unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
{
unsigned long weight = cpumask_weight(sched_domain_span(sd));
unsigned long smt_gain = sd->smt_gain;
@@ -3721,6 +3573,11 @@ unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
return smt_gain;
}
unsigned long __weak arch_scale_smt_power(struct sched_domain *sd, int cpu)
{
return default_scale_smt_power(sd, cpu);
}
unsigned long scale_rt_power(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@@ -3745,10 +3602,19 @@ static void update_cpu_power(struct sched_domain *sd, int cpu)
unsigned long power = SCHED_LOAD_SCALE;
struct sched_group *sdg = sd->groups;
/* here we could scale based on cpufreq */
if (sched_feat(ARCH_POWER))
power *= arch_scale_freq_power(sd, cpu);
else
power *= default_scale_freq_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT;
if ((sd->flags & SD_SHARE_CPUPOWER) && weight > 1) {
power *= arch_scale_smt_power(sd, cpu);
if (sched_feat(ARCH_POWER))
power *= arch_scale_smt_power(sd, cpu);
else
power *= default_scale_smt_power(sd, cpu);
power >>= SCHED_LOAD_SHIFT;
}
@@ -4161,26 +4027,6 @@ ret:
return NULL;
}
static struct sched_group *group_of(int cpu)
{
struct sched_domain *sd = rcu_dereference(cpu_rq(cpu)->sd);
if (!sd)
return NULL;
return sd->groups;
}
static unsigned long power_of(int cpu)
{
struct sched_group *group = group_of(cpu);
if (!group)
return SCHED_LOAD_SCALE;
return group->cpu_power;
}
/*
* find_busiest_queue - find the busiest runqueue among the cpus in group.
*/
@@ -5465,14 +5311,13 @@ static inline void schedule_debug(struct task_struct *prev)
#endif
}
static void put_prev_task(struct rq *rq, struct task_struct *prev)
static void put_prev_task(struct rq *rq, struct task_struct *p)
{
if (prev->state == TASK_RUNNING) {
u64 runtime = prev->se.sum_exec_runtime;
u64 runtime = p->se.sum_exec_runtime - p->se.prev_sum_exec_runtime;
runtime -= prev->se.prev_sum_exec_runtime;
runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
update_avg(&p->se.avg_running, runtime);
if (p->state == TASK_RUNNING) {
/*
* In order to avoid avg_overlap growing stale when we are
* indeed overlapping and hence not getting put to sleep, grow
@@ -5482,9 +5327,12 @@ static void put_prev_task(struct rq *rq, struct task_struct *prev)
* correlates to the amount of cache footprint a task can
* build up.
*/
update_avg(&prev->se.avg_overlap, runtime);
runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
update_avg(&p->se.avg_overlap, runtime);
} else {
update_avg(&p->se.avg_running, 0);
}
prev->sched_class->put_prev_task(rq, prev);
p->sched_class->put_prev_task(rq, p);
}
/*
@@ -5716,10 +5564,10 @@ asmlinkage void __sched preempt_schedule_irq(void)
#endif /* CONFIG_PREEMPT */
int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
void *key)
{
return try_to_wake_up(curr->private, mode, sync);
return try_to_wake_up(curr->private, mode, wake_flags);
}
EXPORT_SYMBOL(default_wake_function);
@@ -5733,14 +5581,14 @@ EXPORT_SYMBOL(default_wake_function);
* zero in this (rare) case, and we handle it by continuing to scan the queue.
*/
static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, int sync, void *key)
int nr_exclusive, int wake_flags, void *key)
{
wait_queue_t *curr, *next;
list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
unsigned flags = curr->flags;
if (curr->func(curr, mode, sync, key) &&
if (curr->func(curr, mode, wake_flags, key) &&
(flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
break;
}
@@ -5801,16 +5649,16 @@ void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, void *key)
{
unsigned long flags;
int sync = 1;
int wake_flags = WF_SYNC;
if (unlikely(!q))
return;
if (unlikely(!nr_exclusive))
sync = 0;
wake_flags = 0;
spin_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr_exclusive, sync, key);
__wake_up_common(q, mode, nr_exclusive, wake_flags, key);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL_GPL(__wake_up_sync_key);
@@ -8000,9 +7848,7 @@ static int sd_degenerate(struct sched_domain *sd)
}
/* Following flags don't use groups */
if (sd->flags & (SD_WAKE_IDLE |
SD_WAKE_AFFINE |
SD_WAKE_BALANCE))
if (sd->flags & (SD_WAKE_AFFINE))
return 0;
return 1;
@@ -8019,10 +7865,6 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
return 0;
/* Does parent contain flags not in child? */
/* WAKE_BALANCE is a subset of WAKE_AFFINE */
if (cflags & SD_WAKE_AFFINE)
pflags &= ~SD_WAKE_BALANCE;
/* Flags needing groups don't count if only 1 group in parent */
if (parent->groups == parent->groups->next) {
pflags &= ~(SD_LOAD_BALANCE |
@@ -8708,10 +8550,10 @@ static void set_domain_attribute(struct sched_domain *sd,
request = attr->relax_domain_level;
if (request < sd->level) {
/* turn off idle balance on this domain */
sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
} else {
/* turn on idle balance on this domain */
sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
}
}

1
kernel/sched_debug.c
View File

@@ -395,6 +395,7 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
PN(se.sum_exec_runtime);
PN(se.avg_overlap);
PN(se.avg_wakeup);
PN(se.avg_running);
nr_switches = p->nvcsw + p->nivcsw;

416
kernel/sched_fair.c
View File

@@ -711,7 +711,7 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
if (!initial) {
/* sleeps upto a single latency don't count. */
if (sched_feat(NEW_FAIR_SLEEPERS)) {
if (sched_feat(FAIR_SLEEPERS)) {
unsigned long thresh = sysctl_sched_latency;
/*
@@ -725,6 +725,13 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial)
task_of(se)->policy != SCHED_IDLE))
thresh = calc_delta_fair(thresh, se);
/*
* Halve their sleep time's effect, to allow
* for a gentler effect of sleepers:
*/
if (sched_feat(GENTLE_FAIR_SLEEPERS))
thresh >>= 1;
vruntime -= thresh;
}
}
@@ -757,10 +764,10 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
if (cfs_rq->last == se)
if (!se || cfs_rq->last == se)
cfs_rq->last = NULL;
if (cfs_rq->next == se)
if (!se || cfs_rq->next == se)
cfs_rq->next = NULL;
}
@@ -1062,83 +1069,6 @@ static void yield_task_fair(struct rq *rq)
se->vruntime = rightmost->vruntime + 1;
}
/*
* wake_idle() will wake a task on an idle cpu if task->cpu is
* not idle and an idle cpu is available. The span of cpus to
* search starts with cpus closest then further out as needed,
* so we always favor a closer, idle cpu.
* Domains may include CPUs that are not usable for migration,
* hence we need to mask them out (rq->rd->online)
*
* Returns the CPU we should wake onto.
*/
#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
#define cpu_rd_active(cpu, rq) cpumask_test_cpu(cpu, rq->rd->online)
static int wake_idle(int cpu, struct task_struct *p)
{
struct sched_domain *sd;
int i;
unsigned int chosen_wakeup_cpu;
int this_cpu;
struct rq *task_rq = task_rq(p);
/*
* At POWERSAVINGS_BALANCE_WAKEUP level, if both this_cpu and prev_cpu
* are idle and this is not a kernel thread and this task's affinity
* allows it to be moved to preferred cpu, then just move!
*/
this_cpu = smp_processor_id();
chosen_wakeup_cpu =
cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu;
if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP &&
idle_cpu(cpu) && idle_cpu(this_cpu) &&
p->mm && !(p->flags & PF_KTHREAD) &&
cpu_isset(chosen_wakeup_cpu, p->cpus_allowed))
return chosen_wakeup_cpu;
/*
* If it is idle, then it is the best cpu to run this task.
*
* This cpu is also the best, if it has more than one task already.
* Siblings must be also busy(in most cases) as they didn't already
* pickup the extra load from this cpu and hence we need not check
* sibling runqueue info. This will avoid the checks and cache miss
* penalities associated with that.
*/
if (idle_cpu(cpu) || cpu_rq(cpu)->cfs.nr_running > 1)
return cpu;
for_each_domain(cpu, sd) {
if ((sd->flags & SD_WAKE_IDLE)
|| ((sd->flags & SD_WAKE_IDLE_FAR)
&& !task_hot(p, task_rq->clock, sd))) {
for_each_cpu_and(i, sched_domain_span(sd),
&p->cpus_allowed) {
if (cpu_rd_active(i, task_rq) && idle_cpu(i)) {
if (i != task_cpu(p)) {
schedstat_inc(p,
se.nr_wakeups_idle);
}
return i;
}
}
} else {
break;
}
}
return cpu;
}
#else /* !ARCH_HAS_SCHED_WAKE_IDLE*/
static inline int wake_idle(int cpu, struct task_struct *p)
{
return cpu;
}
#endif
#ifdef CONFIG_SMP
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -1225,25 +1155,34 @@ static inline unsigned long effective_load(struct task_group *tg, int cpu,
#endif
static int
wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
struct task_struct *p, int prev_cpu, int this_cpu, int sync,
int idx, unsigned long load, unsigned long this_load,
unsigned int imbalance)
static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
{
struct task_struct *curr = this_rq->curr;
struct task_group *tg;
unsigned long tl = this_load;
struct task_struct *curr = current;
unsigned long this_load, load;
int idx, this_cpu, prev_cpu;
unsigned long tl_per_task;
unsigned int imbalance;
struct task_group *tg;
unsigned long weight;
int balanced;
if (!(this_sd->flags & SD_WAKE_AFFINE) || !sched_feat(AFFINE_WAKEUPS))
return 0;
idx = sd->wake_idx;
this_cpu = smp_processor_id();
prev_cpu = task_cpu(p);
load = source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
if (sync && (curr->se.avg_overlap > sysctl_sched_migration_cost ||
p->se.avg_overlap > sysctl_sched_migration_cost))
sync = 0;
if (sync) {
if (sched_feat(SYNC_LESS) &&
(curr->se.avg_overlap > sysctl_sched_migration_cost ||
p->se.avg_overlap > sysctl_sched_migration_cost))
sync = 0;
} else {
if (sched_feat(SYNC_MORE) &&
(curr->se.avg_overlap < sysctl_sched_migration_cost &&
p->se.avg_overlap < sysctl_sched_migration_cost))
sync = 1;
}
/*
* If sync wakeup then subtract the (maximum possible)
@@ -1254,24 +1193,26 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
tg = task_group(current);
weight = current->se.load.weight;
tl += effective_load(tg, this_cpu, -weight, -weight);
this_load += effective_load(tg, this_cpu, -weight, -weight);
load += effective_load(tg, prev_cpu, 0, -weight);
}
tg = task_group(p);
weight = p->se.load.weight;
imbalance = 100 + (sd->imbalance_pct - 100) / 2;
/*
* In low-load situations, where prev_cpu is idle and this_cpu is idle
* due to the sync cause above having dropped tl to 0, we'll always have
* an imbalance, but there's really nothing you can do about that, so
* that's good too.
* due to the sync cause above having dropped this_load to 0, we'll
* always have an imbalance, but there's really nothing you can do
* about that, so that's good too.
*
* Otherwise check if either cpus are near enough in load to allow this
* task to be woken on this_cpu.
*/
balanced = !tl ||
100*(tl + effective_load(tg, this_cpu, weight, weight)) <=
balanced = !this_load ||
100*(this_load + effective_load(tg, this_cpu, weight, weight)) <=
imbalance*(load + effective_load(tg, prev_cpu, 0, weight));
/*
@@ -1285,14 +1226,15 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
schedstat_inc(p, se.nr_wakeups_affine_attempts);
tl_per_task = cpu_avg_load_per_task(this_cpu);
if (balanced || (tl <= load && tl + target_load(prev_cpu, idx) <=
tl_per_task)) {
if (balanced ||
(this_load <= load &&
this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and
* there is no bad imbalance.
*/
schedstat_inc(this_sd, ttwu_move_affine);
schedstat_inc(sd, ttwu_move_affine);
schedstat_inc(p, se.nr_wakeups_affine);
return 1;
@@ -1300,65 +1242,215 @@ wake_affine(struct sched_domain *this_sd, struct rq *this_rq,
return 0;
}
static int select_task_rq_fair(struct task_struct *p, int sync)
/*
* find_idlest_group finds and returns the least busy CPU group within the
* domain.
*/
static struct sched_group *
find_idlest_group(struct sched_domain *sd, struct task_struct *p,
int this_cpu, int load_idx)
{
struct sched_domain *sd, *this_sd = NULL;
int prev_cpu, this_cpu, new_cpu;
unsigned long load, this_load;
struct rq *this_rq;
unsigned int imbalance;
int idx;
struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
unsigned long min_load = ULONG_MAX, this_load = 0;
int imbalance = 100 + (sd->imbalance_pct-100)/2;
prev_cpu = task_cpu(p);
this_cpu = smp_processor_id();
this_rq = cpu_rq(this_cpu);
new_cpu = prev_cpu;
do {
unsigned long load, avg_load;
int local_group;
int i;
/*
* 'this_sd' is the first domain that both
* this_cpu and prev_cpu are present in:
*/
for_each_domain(this_cpu, sd) {
if (cpumask_test_cpu(prev_cpu, sched_domain_span(sd))) {
this_sd = sd;
break;
/* Skip over this group if it has no CPUs allowed */
if (!cpumask_intersects(sched_group_cpus(group),
&p->cpus_allowed))
continue;
local_group = cpumask_test_cpu(this_cpu,
sched_group_cpus(group));
/* Tally up the load of all CPUs in the group */
avg_load = 0;
for_each_cpu(i, sched_group_cpus(group)) {
/* Bias balancing toward cpus of our domain */
if (local_group)
load = source_load(i, load_idx);
else
load = target_load(i, load_idx);
avg_load += load;
}
/* Adjust by relative CPU power of the group */
avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
if (local_group) {
this_load = avg_load;
this = group;
} else if (avg_load < min_load) {
min_load = avg_load;
idlest = group;
}
} while (group = group->next, group != sd->groups);
if (!idlest || 100*this_load < imbalance*min_load)
return NULL;
return idlest;
}
/*
* find_idlest_cpu - find the idlest cpu among the cpus in group.
*/
static int
find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
{
unsigned long load, min_load = ULONG_MAX;
int idlest = -1;
int i;
/* Traverse only the allowed CPUs */
for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {
load = weighted_cpuload(i);
if (load < min_load || (load == min_load && i == this_cpu)) {
min_load = load;
idlest = i;
}
}
if (unlikely(!cpumask_test_cpu(this_cpu, &p->cpus_allowed)))
goto out;
return idlest;
}
/*
* Check for affine wakeup and passive balancing possibilities.
*/
if (!this_sd)
goto out;
/*
* sched_balance_self: balance the current task (running on cpu) in domains
* that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
* SD_BALANCE_EXEC.
*
* Balance, ie. select the least loaded group.
*
* Returns the target CPU number, or the same CPU if no balancing is needed.
*
* preempt must be disabled.
*/
static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags)
{
struct sched_domain *tmp, *affine_sd = NULL, *sd = NULL;
int cpu = smp_processor_id();
int prev_cpu = task_cpu(p);
int new_cpu = cpu;
int want_affine = 0;
int want_sd = 1;
int sync = wake_flags & WF_SYNC;
idx = this_sd->wake_idx;
if (sd_flag & SD_BALANCE_WAKE) {
if (sched_feat(AFFINE_WAKEUPS))
want_affine = 1;
new_cpu = prev_cpu;
}
imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
rcu_read_lock();
for_each_domain(cpu, tmp) {
/*
* If power savings logic is enabled for a domain, see if we
* are not overloaded, if so, don't balance wider.
*/
if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) {
unsigned long power = 0;
unsigned long nr_running = 0;
unsigned long capacity;
int i;
load = source_load(prev_cpu, idx);
this_load = target_load(this_cpu, idx);
for_each_cpu(i, sched_domain_span(tmp)) {
power += power_of(i);
nr_running += cpu_rq(i)->cfs.nr_running;
}
if (wake_affine(this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
load, this_load, imbalance))
return this_cpu;
capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);
/*
* Start passive balancing when half the imbalance_pct
* limit is reached.
*/
if (this_sd->flags & SD_WAKE_BALANCE) {
if (imbalance*this_load <= 100*load) {
schedstat_inc(this_sd, ttwu_move_balance);
schedstat_inc(p, se.nr_wakeups_passive);
return this_cpu;
if (tmp->flags & SD_POWERSAVINGS_BALANCE)
nr_running /= 2;
if (nr_running < capacity)
want_sd = 0;
}
if (want_affine && (tmp->flags & SD_WAKE_AFFINE) &&
cpumask_test_cpu(prev_cpu, sched_domain_span(tmp))) {
affine_sd = tmp;
want_affine = 0;
}
if (!want_sd && !want_affine)
break;
if (!(tmp->flags & sd_flag))
continue;
if (want_sd)
sd = tmp;
}
if (sched_feat(LB_SHARES_UPDATE)) {
/*
* Pick the largest domain to update shares over
*/
tmp = sd;
if (affine_sd && (!tmp ||
cpumask_weight(sched_domain_span(affine_sd)) >
cpumask_weight(sched_domain_span(sd))))
tmp = affine_sd;
if (tmp)
update_shares(tmp);
}
if (affine_sd && wake_affine(affine_sd, p, sync)) {
new_cpu = cpu;
goto out;
}
while (sd) {
int load_idx = sd->forkexec_idx;
struct sched_group *group;
int weight;
if (!(sd->flags & sd_flag)) {
sd = sd->child;
continue;
}
if (sd_flag & SD_BALANCE_WAKE)
load_idx = sd->wake_idx;
group = find_idlest_group(sd, p, cpu, load_idx);
if (!group) {
sd = sd->child;
continue;
}
new_cpu = find_idlest_cpu(group, p, cpu);
if (new_cpu == -1 || new_cpu == cpu) {
/* Now try balancing at a lower domain level of cpu */
sd = sd->child;
continue;
}
/* Now try balancing at a lower domain level of new_cpu */
cpu = new_cpu;
weight = cpumask_weight(sched_domain_span(sd));
sd = NULL;
for_each_domain(cpu, tmp) {
if (weight <= cpumask_weight(sched_domain_span(tmp)))
break;
if (tmp->flags & sd_flag)
sd = tmp;
}
/* while loop will break here if sd == NULL */
}
out:
return wake_idle(new_cpu, p);
rcu_read_unlock();
return new_cpu;
}
#endif /* CONFIG_SMP */
@@ -1471,11 +1563,12 @@ static void set_next_buddy(struct sched_entity *se)
/*
* Preempt the current task with a newly woken task if needed:
*/
static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
{
struct task_struct *curr = rq->curr;
struct sched_entity *se = &curr->se, *pse = &p->se;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
int sync = wake_flags & WF_SYNC;
update_curr(cfs_rq);
@@ -1501,7 +1594,8 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
*/
if (sched_feat(LAST_BUDDY) && likely(se->on_rq && curr != rq->idle))
set_last_buddy(se);
set_next_buddy(pse);
if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK))
set_next_buddy(pse);
/*
* We can come here with TIF_NEED_RESCHED already set from new task
@@ -1523,16 +1617,25 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int sync)
return;
}
if (!sched_feat(WAKEUP_PREEMPT))
return;
if (sched_feat(WAKEUP_OVERLAP) && (sync ||
(se->avg_overlap < sysctl_sched_migration_cost &&
pse->avg_overlap < sysctl_sched_migration_cost))) {
if ((sched_feat(WAKEUP_SYNC) && sync) ||
(sched_feat(WAKEUP_OVERLAP) &&
(se->avg_overlap < sysctl_sched_migration_cost &&
pse->avg_overlap < sysctl_sched_migration_cost))) {
resched_task(curr);
return;
}
if (sched_feat(WAKEUP_RUNNING)) {
if (pse->avg_running < se->avg_running) {
set_next_buddy(pse);
resched_task(curr);
return;
}
}
if (!sched_feat(WAKEUP_PREEMPT))
return;
find_matching_se(&se, &pse);
BUG_ON(!pse);
@@ -1555,8 +1658,13 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
/*
* If se was a buddy, clear it so that it will have to earn
* the favour again.
*
* If se was not a buddy, clear the buddies because neither
* was elegible to run, let them earn it again.
*
* IOW. unconditionally clear buddies.
*/
__clear_buddies(cfs_rq, se);
__clear_buddies(cfs_rq, NULL);
set_next_entity(cfs_rq, se);
cfs_rq = group_cfs_rq(se);
} while (cfs_rq);

124
kernel/sched_features.h
View File

@@ -1,17 +1,123 @@
SCHED_FEAT(NEW_FAIR_SLEEPERS, 0)
/*
* Disregards a certain amount of sleep time (sched_latency_ns) and
* considers the task to be running during that period. This gives it
* a service deficit on wakeup, allowing it to run sooner.
*/
SCHED_FEAT(FAIR_SLEEPERS, 1)
/*
* Only give sleepers 50% of their service deficit. This allows
* them to run sooner, but does not allow tons of sleepers to
* rip the spread apart.
*/
SCHED_FEAT(GENTLE_FAIR_SLEEPERS, 1)
/*
* By not normalizing the sleep time, heavy tasks get an effective
* longer period, and lighter task an effective shorter period they
* are considered running.
*/
SCHED_FEAT(NORMALIZED_SLEEPER, 0)
SCHED_FEAT(ADAPTIVE_GRAN, 1)
SCHED_FEAT(WAKEUP_PREEMPT, 1)
/*
* Place new tasks ahead so that they do not starve already running
* tasks
*/
SCHED_FEAT(START_DEBIT, 1)
SCHED_FEAT(AFFINE_WAKEUPS, 1)
SCHED_FEAT(CACHE_HOT_BUDDY, 1)
/*
* Should wakeups try to preempt running tasks.
*/
SCHED_FEAT(WAKEUP_PREEMPT, 1)
/*
* Compute wakeup_gran based on task behaviour, clipped to
* [0, sched_wakeup_gran_ns]
*/
SCHED_FEAT(ADAPTIVE_GRAN, 1)
/*
* When converting the wakeup granularity to virtual time, do it such
* that heavier tasks preempting a lighter task have an edge.
*/
SCHED_FEAT(ASYM_GRAN, 1)
/*
* Always wakeup-preempt SYNC wakeups, see SYNC_WAKEUPS.
*/
SCHED_FEAT(WAKEUP_SYNC, 0)
/*
* Wakeup preempt based on task behaviour. Tasks that do not overlap
* don't get preempted.
*/
SCHED_FEAT(WAKEUP_OVERLAP, 0)
/*
* Wakeup preemption towards tasks that run short
*/
SCHED_FEAT(WAKEUP_RUNNING, 0)
/*
* Use the SYNC wakeup hint, pipes and the likes use this to indicate
* the remote end is likely to consume the data we just wrote, and
* therefore has cache benefit from being placed on the same cpu, see
* also AFFINE_WAKEUPS.
*/
SCHED_FEAT(SYNC_WAKEUPS, 1)
/*
* Based on load and program behaviour, see if it makes sense to place
* a newly woken task on the same cpu as the task that woke it --
* improve cache locality. Typically used with SYNC wakeups as
* generated by pipes and the like, see also SYNC_WAKEUPS.
*/
SCHED_FEAT(AFFINE_WAKEUPS, 1)
/*
* Weaken SYNC hint based on overlap
*/
SCHED_FEAT(SYNC_LESS, 1)
/*
* Add SYNC hint based on overlap
*/
SCHED_FEAT(SYNC_MORE, 0)
/*
* Prefer to schedule the task we woke last (assuming it failed
* wakeup-preemption), since its likely going to consume data we
* touched, increases cache locality.
*/
SCHED_FEAT(NEXT_BUDDY, 0)
/*
* Prefer to schedule the task that ran last (when we did
* wake-preempt) as that likely will touch the same data, increases
* cache locality.
*/
SCHED_FEAT(LAST_BUDDY, 1)
/*
* Consider buddies to be cache hot, decreases the likelyness of a
* cache buddy being migrated away, increases cache locality.
*/
SCHED_FEAT(CACHE_HOT_BUDDY, 1)
/*
* Use arch dependent cpu power functions
*/
SCHED_FEAT(ARCH_POWER, 0)
SCHED_FEAT(HRTICK, 0)
SCHED_FEAT(DOUBLE_TICK, 0)
SCHED_FEAT(ASYM_GRAN, 1)
SCHED_FEAT(LB_BIAS, 1)
SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
SCHED_FEAT(LB_SHARES_UPDATE, 1)
SCHED_FEAT(ASYM_EFF_LOAD, 1)
SCHED_FEAT(WAKEUP_OVERLAP, 0)
SCHED_FEAT(LAST_BUDDY, 1)
/*
* Spin-wait on mutex acquisition when the mutex owner is running on
* another cpu -- assumes that when the owner is running, it will soon
* release the lock. Decreases scheduling overhead.
*/
SCHED_FEAT(OWNER_SPIN, 1)

4
kernel/sched_idletask.c
View File

@@ -6,7 +6,7 @@
*/
#ifdef CONFIG_SMP
static int select_task_rq_idle(struct task_struct *p, int sync)
static int select_task_rq_idle(struct task_struct *p, int sd_flag, int flags)
{
return task_cpu(p); /* IDLE tasks as never migrated */
}
@@ -14,7 +14,7 @@ static int select_task_rq_idle(struct task_struct *p, int sync)
/*
* Idle tasks are unconditionally rescheduled:
*/
static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int sync)
static void check_preempt_curr_idle(struct rq *rq, struct task_struct *p, int flags)
{
resched_task(rq->idle);
}

7
kernel/sched_rt.c
View File

@@ -938,10 +938,13 @@ static void yield_task_rt(struct rq *rq)
#ifdef CONFIG_SMP
static int find_lowest_rq(struct task_struct *task);
static int select_task_rq_rt(struct task_struct *p, int sync)
static int select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
{
struct rq *rq = task_rq(p);
if (sd_flag != SD_BALANCE_WAKE)
return smp_processor_id();
/*
* If the current task is an RT task, then
* try to see if we can wake this RT task up on another
@@ -999,7 +1002,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
/*
* Preempt the current task with a newly woken task if needed:
*/
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int sync)
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
{
if (p->prio < rq->curr->prio) {
resched_task(rq->curr);