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-rw-r--r--kernel/sched.c354
1 files changed, 134 insertions, 220 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 34bcc5bc120..cfa222a9153 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -75,16 +75,6 @@
#include <asm/irq_regs.h>
/*
- * Scheduler clock - returns current time in nanosec units.
- * This is default implementation.
- * Architectures and sub-architectures can override this.
- */
-unsigned long long __attribute__((weak)) sched_clock(void)
-{
- return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
-}
-
-/*
* Convert user-nice values [ -20 ... 0 ... 19 ]
* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
* and back.
@@ -242,6 +232,12 @@ static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
}
#endif
+/*
+ * sched_domains_mutex serializes calls to arch_init_sched_domains,
+ * detach_destroy_domains and partition_sched_domains.
+ */
+static DEFINE_MUTEX(sched_domains_mutex);
+
#ifdef CONFIG_GROUP_SCHED
#include <linux/cgroup.h>
@@ -308,9 +304,6 @@ static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
*/
static DEFINE_SPINLOCK(task_group_lock);
-/* doms_cur_mutex serializes access to doms_cur[] array */
-static DEFINE_MUTEX(doms_cur_mutex);
-
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_USER_SCHED
# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
@@ -318,7 +311,13 @@ static DEFINE_MUTEX(doms_cur_mutex);
# define INIT_TASK_GROUP_LOAD NICE_0_LOAD
#endif
+/*
+ * A weight of 0, 1 or ULONG_MAX can cause arithmetics problems.
+ * (The default weight is 1024 - so there's no practical
+ * limitation from this.)
+ */
#define MIN_SHARES 2
+#define MAX_SHARES (ULONG_MAX - 1)
static int init_task_group_load = INIT_TASK_GROUP_LOAD;
#endif
@@ -358,21 +357,9 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
#endif
}
-static inline void lock_doms_cur(void)
-{
- mutex_lock(&doms_cur_mutex);
-}
-
-static inline void unlock_doms_cur(void)
-{
- mutex_unlock(&doms_cur_mutex);
-}
-
#else
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
-static inline void lock_doms_cur(void) { }
-static inline void unlock_doms_cur(void) { }
#endif /* CONFIG_GROUP_SCHED */
@@ -560,13 +547,7 @@ struct rq {
unsigned long next_balance;
struct mm_struct *prev_mm;
- u64 clock, prev_clock_raw;
- s64 clock_max_delta;
-
- unsigned int clock_warps, clock_overflows, clock_underflows;
- u64 idle_clock;
- unsigned int clock_deep_idle_events;
- u64 tick_timestamp;
+ u64 clock;
atomic_t nr_iowait;
@@ -631,82 +612,6 @@ static inline int cpu_of(struct rq *rq)
#endif
}
-#ifdef CONFIG_NO_HZ
-static inline bool nohz_on(int cpu)
-{
- return tick_get_tick_sched(cpu)->nohz_mode != NOHZ_MODE_INACTIVE;
-}
-
-static inline u64 max_skipped_ticks(struct rq *rq)
-{
- return nohz_on(cpu_of(rq)) ? jiffies - rq->last_tick_seen + 2 : 1;
-}
-
-static inline void update_last_tick_seen(struct rq *rq)
-{
- rq->last_tick_seen = jiffies;
-}
-#else
-static inline u64 max_skipped_ticks(struct rq *rq)
-{
- return 1;
-}
-
-static inline void update_last_tick_seen(struct rq *rq)
-{
-}
-#endif
-
-/*
- * Update the per-runqueue clock, as finegrained as the platform can give
- * us, but without assuming monotonicity, etc.:
- */
-static void __update_rq_clock(struct rq *rq)
-{
- u64 prev_raw = rq->prev_clock_raw;
- u64 now = sched_clock();
- s64 delta = now - prev_raw;
- u64 clock = rq->clock;
-
-#ifdef CONFIG_SCHED_DEBUG
- WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
-#endif
- /*
- * Protect against sched_clock() occasionally going backwards:
- */
- if (unlikely(delta < 0)) {
- clock++;
- rq->clock_warps++;
- } else {
- /*
- * Catch too large forward jumps too:
- */
- u64 max_jump = max_skipped_ticks(rq) * TICK_NSEC;
- u64 max_time = rq->tick_timestamp + max_jump;
-
- if (unlikely(clock + delta > max_time)) {
- if (clock < max_time)
- clock = max_time;
- else
- clock++;
- rq->clock_overflows++;
- } else {
- if (unlikely(delta > rq->clock_max_delta))
- rq->clock_max_delta = delta;
- clock += delta;
- }
- }
-
- rq->prev_clock_raw = now;
- rq->clock = clock;
-}
-
-static void update_rq_clock(struct rq *rq)
-{
- if (likely(smp_processor_id() == cpu_of(rq)))
- __update_rq_clock(rq);
-}
-
/*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition.
* See detach_destroy_domains: synchronize_sched for details.
@@ -722,6 +627,11 @@ static void update_rq_clock(struct rq *rq)
#define task_rq(p) cpu_rq(task_cpu(p))
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
+static inline void update_rq_clock(struct rq *rq)
+{
+ rq->clock = sched_clock_cpu(cpu_of(rq));
+}
+
/*
* Tunables that become constants when CONFIG_SCHED_DEBUG is off:
*/
@@ -757,14 +667,14 @@ const_debug unsigned int sysctl_sched_features =
#define SCHED_FEAT(name, enabled) \
#name ,
-__read_mostly char *sched_feat_names[] = {
+static __read_mostly char *sched_feat_names[] = {
#include "sched_features.h"
NULL
};
#undef SCHED_FEAT
-int sched_feat_open(struct inode *inode, struct file *filp)
+static int sched_feat_open(struct inode *inode, struct file *filp)
{
filp->private_data = inode->i_private;
return 0;
@@ -899,7 +809,7 @@ static inline u64 global_rt_runtime(void)
return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
}
-static const unsigned long long time_sync_thresh = 100000;
+unsigned long long time_sync_thresh = 100000;
static DEFINE_PER_CPU(unsigned long long, time_offset);
static DEFINE_PER_CPU(unsigned long long, prev_cpu_time);
@@ -913,11 +823,14 @@ static DEFINE_PER_CPU(unsigned long long, prev_cpu_time);
static DEFINE_SPINLOCK(time_sync_lock);
static unsigned long long prev_global_time;
-static unsigned long long __sync_cpu_clock(cycles_t time, int cpu)
+static unsigned long long __sync_cpu_clock(unsigned long long time, int cpu)
{
- unsigned long flags;
-
- spin_lock_irqsave(&time_sync_lock, flags);
+ /*
+ * We want this inlined, to not get tracer function calls
+ * in this critical section:
+ */
+ spin_acquire(&time_sync_lock.dep_map, 0, 0, _THIS_IP_);
+ __raw_spin_lock(&time_sync_lock.raw_lock);
if (time < prev_global_time) {
per_cpu(time_offset, cpu) += prev_global_time - time;
@@ -926,7 +839,8 @@ static unsigned long long __sync_cpu_clock(cycles_t time, int cpu)
prev_global_time = time;
}
- spin_unlock_irqrestore(&time_sync_lock, flags);
+ __raw_spin_unlock(&time_sync_lock.raw_lock);
+ spin_release(&time_sync_lock.dep_map, 1, _THIS_IP_);
return time;
}
@@ -934,8 +848,6 @@ static unsigned long long __sync_cpu_clock(cycles_t time, int cpu)
static unsigned long long __cpu_clock(int cpu)
{
unsigned long long now;
- unsigned long flags;
- struct rq *rq;
/*
* Only call sched_clock() if the scheduler has already been
@@ -944,11 +856,7 @@ static unsigned long long __cpu_clock(int cpu)
if (unlikely(!scheduler_running))
return 0;
- local_irq_save(flags);
- rq = cpu_rq(cpu);
- update_rq_clock(rq);
- now = rq->clock;
- local_irq_restore(flags);
+ now = sched_clock_cpu(cpu);
return now;
}
@@ -960,13 +868,18 @@ static unsigned long long __cpu_clock(int cpu)
unsigned long long cpu_clock(int cpu)
{
unsigned long long prev_cpu_time, time, delta_time;
+ unsigned long flags;
+ local_irq_save(flags);
prev_cpu_time = per_cpu(prev_cpu_time, cpu);
time = __cpu_clock(cpu) + per_cpu(time_offset, cpu);
delta_time = time-prev_cpu_time;
- if (unlikely(delta_time > time_sync_thresh))
+ if (unlikely(delta_time > time_sync_thresh)) {
time = __sync_cpu_clock(time, cpu);
+ per_cpu(prev_cpu_time, cpu) = time;
+ }
+ local_irq_restore(flags);
return time;
}
@@ -1117,43 +1030,6 @@ static struct rq *this_rq_lock(void)
return rq;
}
-/*
- * We are going deep-idle (irqs are disabled):
- */
-void sched_clock_idle_sleep_event(void)
-{
- struct rq *rq = cpu_rq(smp_processor_id());
-
- spin_lock(&rq->lock);
- __update_rq_clock(rq);
- spin_unlock(&rq->lock);
- rq->clock_deep_idle_events++;
-}
-EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
-
-/*
- * We just idled delta nanoseconds (called with irqs disabled):
- */
-void sched_clock_idle_wakeup_event(u64 delta_ns)
-{
- struct rq *rq = cpu_rq(smp_processor_id());
- u64 now = sched_clock();
-
- rq->idle_clock += delta_ns;
- /*
- * Override the previous timestamp and ignore all
- * sched_clock() deltas that occured while we idled,
- * and use the PM-provided delta_ns to advance the
- * rq clock:
- */
- spin_lock(&rq->lock);
- rq->prev_clock_raw = now;
- rq->clock += delta_ns;
- spin_unlock(&rq->lock);
- touch_softlockup_watchdog();
-}
-EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
-
static void __resched_task(struct task_struct *p, int tif_bit);
static inline void resched_task(struct task_struct *p)
@@ -1189,6 +1065,7 @@ static inline void resched_rq(struct rq *rq)
enum {
HRTICK_SET, /* re-programm hrtick_timer */
HRTICK_RESET, /* not a new slice */
+ HRTICK_BLOCK, /* stop hrtick operations */
};
/*
@@ -1200,6 +1077,8 @@ static inline int hrtick_enabled(struct rq *rq)
{
if (!sched_feat(HRTICK))
return 0;
+ if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
+ return 0;
return hrtimer_is_hres_active(&rq->hrtick_timer);
}
@@ -1275,14 +1154,70 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
spin_lock(&rq->lock);
- __update_rq_clock(rq);
+ update_rq_clock(rq);
rq->curr->sched_class->task_tick(rq, rq->curr, 1);
spin_unlock(&rq->lock);
return HRTIMER_NORESTART;
}
-static inline void init_rq_hrtick(struct rq *rq)
+static void hotplug_hrtick_disable(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rq->lock, flags);
+ rq->hrtick_flags = 0;
+ __set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
+ spin_unlock_irqrestore(&rq->lock, flags);
+
+ hrtick_clear(rq);
+}
+
+static void hotplug_hrtick_enable(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
+
+ spin_lock_irqsave(&rq->lock, flags);
+ __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
+ spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+static int
+hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+ int cpu = (int)(long)hcpu;
+
+ switch (action) {
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
+ hotplug_hrtick_disable(cpu);
+ return NOTIFY_OK;
+
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ case CPU_DOWN_FAILED:
+ case CPU_DOWN_FAILED_FROZEN:
+ case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
+ hotplug_hrtick_enable(cpu);
+ return NOTIFY_OK;
+ }
+
+ return NOTIFY_DONE;
+}
+
+static void init_hrtick(void)
+{
+ hotcpu_notifier(hotplug_hrtick, 0);
+}
+
+static void init_rq_hrtick(struct rq *rq)
{
rq->hrtick_flags = 0;
hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
@@ -1319,6 +1254,10 @@ static inline void init_rq_hrtick(struct rq *rq)
void hrtick_resched(void)
{
}
+
+static inline void init_hrtick(void)
+{
+}
#endif
/*
@@ -1438,8 +1377,8 @@ calc_delta_mine(unsigned long delta_exec, unsigned long weight,
{
u64 tmp;
- if (unlikely(!lw->inv_weight))
- lw->inv_weight = (WMULT_CONST-lw->weight/2) / (lw->weight+1);
+ if (!lw->inv_weight)
+ lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)/(lw->weight+1);
tmp = (u64)delta_exec * weight;
/*
@@ -1748,6 +1687,8 @@ __update_group_shares_cpu(struct task_group *tg, struct sched_domain *sd,
if (shares < MIN_SHARES)
shares = MIN_SHARES;
+ else if (shares > MAX_SHARES)
+ shares = MAX_SHARES;
__set_se_shares(tg->se[tcpu], shares);
}
@@ -4339,8 +4280,10 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
struct rq *rq = this_rq();
cputime64_t tmp;
- if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0))
- return account_guest_time(p, cputime);
+ if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
+ account_guest_time(p, cputime);
+ return;
+ }
p->stime = cputime_add(p->stime, cputime);
@@ -4404,19 +4347,11 @@ void scheduler_tick(void)
int cpu = smp_processor_id();
struct rq *rq = cpu_rq(cpu);
struct task_struct *curr = rq->curr;
- u64 next_tick = rq->tick_timestamp + TICK_NSEC;
+
+ sched_clock_tick();
spin_lock(&rq->lock);
- __update_rq_clock(rq);
- /*
- * Let rq->clock advance by at least TICK_NSEC:
- */
- if (unlikely(rq->clock < next_tick)) {
- rq->clock = next_tick;
- rq->clock_underflows++;
- }
- rq->tick_timestamp = rq->clock;
- update_last_tick_seen(rq);
+ update_rq_clock(rq);
update_cpu_load(rq);
curr->sched_class->task_tick(rq, curr, 0);
spin_unlock(&rq->lock);
@@ -4570,7 +4505,7 @@ need_resched_nonpreemptible:
* Do the rq-clock update outside the rq lock:
*/
local_irq_disable();
- __update_rq_clock(rq);
+ update_rq_clock(rq);
spin_lock(&rq->lock);
clear_tsk_need_resched(prev);
@@ -4595,9 +4530,9 @@ need_resched_nonpreemptible:
prev->sched_class->put_prev_task(rq, prev);
next = pick_next_task(rq, prev);
- sched_info_switch(prev, next);
-
if (likely(prev != next)) {
+ sched_info_switch(prev, next);
+
rq->nr_switches++;
rq->curr = next;
++*switch_count;
@@ -4632,8 +4567,6 @@ EXPORT_SYMBOL(schedule);
asmlinkage void __sched preempt_schedule(void)
{
struct thread_info *ti = current_thread_info();
- struct task_struct *task = current;
- int saved_lock_depth;
/*
* If there is a non-zero preempt_count or interrupts are disabled,
@@ -4644,16 +4577,7 @@ asmlinkage void __sched preempt_schedule(void)
do {
add_preempt_count(PREEMPT_ACTIVE);
-
- /*
- * We keep the big kernel semaphore locked, but we
- * clear ->lock_depth so that schedule() doesnt
- * auto-release the semaphore:
- */
- saved_lock_depth = task->lock_depth;
- task->lock_depth = -1;
schedule();
- task->lock_depth = saved_lock_depth;
sub_preempt_count(PREEMPT_ACTIVE);
/*
@@ -4674,26 +4598,15 @@ EXPORT_SYMBOL(preempt_schedule);
asmlinkage void __sched preempt_schedule_irq(void)
{
struct thread_info *ti = current_thread_info();
- struct task_struct *task = current;
- int saved_lock_depth;
/* Catch callers which need to be fixed */
BUG_ON(ti->preempt_count || !irqs_disabled());
do {
add_preempt_count(PREEMPT_ACTIVE);
-
- /*
- * We keep the big kernel semaphore locked, but we
- * clear ->lock_depth so that schedule() doesnt
- * auto-release the semaphore:
- */
- saved_lock_depth = task->lock_depth;
- task->lock_depth = -1;
local_irq_enable();
schedule();
local_irq_disable();
- task->lock_depth = saved_lock_depth;
sub_preempt_count(PREEMPT_ACTIVE);
/*
@@ -5612,7 +5525,6 @@ static void __cond_resched(void)
} while (need_resched());
}
-#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY)
int __sched _cond_resched(void)
{
if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
@@ -5623,7 +5535,6 @@ int __sched _cond_resched(void)
return 0;
}
EXPORT_SYMBOL(_cond_resched);
-#endif
/*
* cond_resched_lock() - if a reschedule is pending, drop the given lock,
@@ -5918,8 +5829,11 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
spin_unlock_irqrestore(&rq->lock, flags);
/* Set the preempt count _outside_ the spinlocks! */
+#if defined(CONFIG_PREEMPT)
+ task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
+#else
task_thread_info(idle)->preempt_count = 0;
-
+#endif
/*
* The idle tasks have their own, simple scheduling class:
*/
@@ -7755,7 +7669,7 @@ void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
{
int i, j;
- lock_doms_cur();
+ mutex_lock(&sched_domains_mutex);
/* always unregister in case we don't destroy any domains */
unregister_sched_domain_sysctl();
@@ -7804,7 +7718,7 @@ match2:
register_sched_domain_sysctl();
- unlock_doms_cur();
+ mutex_unlock(&sched_domains_mutex);
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
@@ -7813,8 +7727,10 @@ int arch_reinit_sched_domains(void)
int err;
get_online_cpus();
+ mutex_lock(&sched_domains_mutex);
detach_destroy_domains(&cpu_online_map);
err = arch_init_sched_domains(&cpu_online_map);
+ mutex_unlock(&sched_domains_mutex);
put_online_cpus();
return err;
@@ -7932,13 +7848,16 @@ void __init sched_init_smp(void)
BUG_ON(sched_group_nodes_bycpu == NULL);
#endif
get_online_cpus();
+ mutex_lock(&sched_domains_mutex);
arch_init_sched_domains(&cpu_online_map);
cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
if (cpus_empty(non_isolated_cpus))
cpu_set(smp_processor_id(), non_isolated_cpus);
+ mutex_unlock(&sched_domains_mutex);
put_online_cpus();
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
+ init_hrtick();
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
@@ -8025,7 +7944,7 @@ static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
se->my_q = cfs_rq;
se->load.weight = tg->shares;
- se->load.inv_weight = div64_u64(1ULL<<32, se->load.weight);
+ se->load.inv_weight = 0;
se->parent = parent;
}
#endif
@@ -8149,8 +8068,6 @@ void __init sched_init(void)
spin_lock_init(&rq->lock);
lockdep_set_class(&rq->lock, &rq->rq_lock_key);
rq->nr_running = 0;
- rq->clock = 1;
- update_last_tick_seen(rq);
init_cfs_rq(&rq->cfs, rq);
init_rt_rq(&rq->rt, rq);
#ifdef CONFIG_FAIR_GROUP_SCHED
@@ -8294,6 +8211,7 @@ EXPORT_SYMBOL(__might_sleep);
static void normalize_task(struct rq *rq, struct task_struct *p)
{
int on_rq;
+
update_rq_clock(rq);
on_rq = p->se.on_rq;
if (on_rq)
@@ -8325,7 +8243,6 @@ void normalize_rt_tasks(void)
p->se.sleep_start = 0;
p->se.block_start = 0;
#endif
- task_rq(p)->clock = 0;
if (!rt_task(p)) {
/*
@@ -8692,7 +8609,7 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares)
dequeue_entity(cfs_rq, se, 0);
se->load.weight = shares;
- se->load.inv_weight = div64_u64((1ULL<<32), shares);
+ se->load.inv_weight = 0;
if (on_rq)
enqueue_entity(cfs_rq, se, 0);
@@ -8722,13 +8639,10 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
if (!tg->se[0])
return -EINVAL;
- /*
- * A weight of 0 or 1 can cause arithmetics problems.
- * (The default weight is 1024 - so there's no practical
- * limitation from this.)
- */
if (shares < MIN_SHARES)
shares = MIN_SHARES;
+ else if (shares > MAX_SHARES)
+ shares = MAX_SHARES;
mutex_lock(&shares_mutex);
if (tg->shares == shares)
@@ -8753,7 +8667,7 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
* force a rebalance
*/
cfs_rq_set_shares(tg->cfs_rq[i], 0);
- set_se_shares(tg->se[i], shares/nr_cpu_ids);
+ set_se_shares(tg->se[i], shares);
}
/*
@@ -9072,7 +8986,7 @@ static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
#endif
#ifdef CONFIG_RT_GROUP_SCHED
-static ssize_t cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
+static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
s64 val)
{
return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);