4.1 System-wide settings
4.2 Task interface
4.3 Default behavior
+ 4.4 Behavior of sched_yield()
5. Tasks CPU affinity
5.1 SCHED_DEADLINE and cpusets HOWTO
6. Future plans
Finally, notice that in order not to jeopardize the admission control a
-deadline task cannot fork.
+
+4.4 Behavior of sched_yield()
+-----------------------------
+
+ When a SCHED_DEADLINE task calls sched_yield(), it gives up its
+ remaining runtime and is immediately throttled, until the next
+ period, when its runtime will be replenished (a special flag
+ dl_yielded is set and used to handle correctly throttling and runtime
+ replenishment after a call to sched_yield()).
+
+ This behavior of sched_yield() allows the task to wake-up exactly at
+ the beginning of the next period. Also, this may be useful in the
+ future with bandwidth reclaiming mechanisms, where sched_yield() will
+ make the leftoever runtime available for reclamation by other
+ SCHED_DEADLINE tasks.
+
+
5. Tasks CPU affinity
=====================
extern struct atomic_notifier_head panic_notifier_list;
extern long (*panic_blink)(int state);
__printf(1, 2)
-void panic(const char *fmt, ...)
- __noreturn __cold;
+void panic(const char *fmt, ...) __noreturn __cold;
void nmi_panic(struct pt_regs *regs, const char *msg);
extern void oops_enter(void);
extern void oops_exit(void);
void print_oops_end_marker(void);
extern int oops_may_print(void);
-void do_exit(long error_code)
- __noreturn;
-void complete_and_exit(struct completion *, long)
- __noreturn;
+void do_exit(long error_code) __noreturn;
+void complete_and_exit(struct completion *, long) __noreturn;
/* Internal, do not use. */
int __must_check _kstrtoul(const char *s, unsigned int base, unsigned long *res);
io_schedule_timeout(MAX_SCHEDULE_TIMEOUT);
}
+void __noreturn do_task_dead(void);
+
struct nsproxy;
struct user_namespace;
#define SD_BALANCE_FORK 0x0008 /* Balance on fork, clone */
#define SD_BALANCE_WAKE 0x0010 /* Balance on wakeup */
#define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */
-#define SD_SHARE_CPUCAPACITY 0x0080 /* Domain members share cpu power */
+#define SD_ASYM_CPUCAPACITY 0x0040 /* Groups have different max cpu capacities */
+#define SD_SHARE_CPUCAPACITY 0x0080 /* Domain members share cpu capacity */
#define SD_SHARE_POWERDOMAIN 0x0100 /* Domain members share power domain */
#define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share cpu pkg resources */
#define SD_SERIALIZE 0x0400 /* Only a single load balancing instance */
* cond_resched_lock() will drop the spinlock before scheduling,
* cond_resched_softirq() will enable bhs before scheduling.
*/
+#ifndef CONFIG_PREEMPT
extern int _cond_resched(void);
+#else
+static inline int _cond_resched(void) { return 0; }
+#endif
#define cond_resched() ({ \
___might_sleep(__FILE__, __LINE__, 0); \
#endif
}
+static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+ return p->preempt_disable_ip;
+#else
+ return 0;
+#endif
+}
+
/*
* Does a critical section need to be broken due to another
* task waiting?: (technically does not depend on CONFIG_PREEMPT,
static inline void check_stack_usage(void) {}
#endif
-void do_exit(long code)
+void __noreturn do_exit(long code)
{
struct task_struct *tsk = current;
int group_dead;
exit_rcu();
TASKS_RCU(__srcu_read_unlock(&tasks_rcu_exit_srcu, tasks_rcu_i));
- /*
- * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
- * when the following two conditions become true.
- * - There is race condition of mmap_sem (It is acquired by
- * exit_mm()), and
- * - SMI occurs before setting TASK_RUNINNG.
- * (or hypervisor of virtual machine switches to other guest)
- * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
- *
- * To avoid it, we have to wait for releasing tsk->pi_lock which
- * is held by try_to_wake_up()
- */
- smp_mb();
- raw_spin_unlock_wait(&tsk->pi_lock);
-
- /* causes final put_task_struct in finish_task_switch(). */
- tsk->state = TASK_DEAD;
- tsk->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
- schedule();
- BUG();
- /* Avoid "noreturn function does return". */
- for (;;)
- cpu_relax(); /* For when BUG is null */
+ do_task_dead();
}
EXPORT_SYMBOL_GPL(do_exit);
* holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
* we're holding p->pi_lock.
*/
- if (task_rq(p) == rq && task_on_rq_queued(p))
- rq = __migrate_task(rq, p, arg->dest_cpu);
+ if (task_rq(p) == rq) {
+ if (task_on_rq_queued(p))
+ rq = __migrate_task(rq, p, arg->dest_cpu);
+ else
+ p->wake_cpu = arg->dest_cpu;
+ }
raw_spin_unlock(&rq->lock);
raw_spin_unlock(&p->pi_lock);
/*
* Task isn't running anymore; make it appear like we migrated
* it before it went to sleep. This means on wakeup we make the
- * previous cpu our targer instead of where it really is.
+ * previous cpu our target instead of where it really is.
*/
p->wake_cpu = cpu;
}
static void
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
{
-#ifdef CONFIG_SCHEDSTATS
- struct rq *rq = this_rq();
+ struct rq *rq;
-#ifdef CONFIG_SMP
- int this_cpu = smp_processor_id();
+ if (!schedstat_enabled())
+ return;
- if (cpu == this_cpu) {
- schedstat_inc(rq, ttwu_local);
- schedstat_inc(p, se.statistics.nr_wakeups_local);
+ rq = this_rq();
+
+#ifdef CONFIG_SMP
+ if (cpu == rq->cpu) {
+ schedstat_inc(rq->ttwu_local);
+ schedstat_inc(p->se.statistics.nr_wakeups_local);
} else {
struct sched_domain *sd;
- schedstat_inc(p, se.statistics.nr_wakeups_remote);
+ schedstat_inc(p->se.statistics.nr_wakeups_remote);
rcu_read_lock();
- for_each_domain(this_cpu, sd) {
+ for_each_domain(rq->cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
- schedstat_inc(sd, ttwu_wake_remote);
+ schedstat_inc(sd->ttwu_wake_remote);
break;
}
}
}
if (wake_flags & WF_MIGRATED)
- schedstat_inc(p, se.statistics.nr_wakeups_migrate);
-
+ schedstat_inc(p->se.statistics.nr_wakeups_migrate);
#endif /* CONFIG_SMP */
- schedstat_inc(rq, ttwu_count);
- schedstat_inc(p, se.statistics.nr_wakeups);
+ schedstat_inc(rq->ttwu_count);
+ schedstat_inc(p->se.statistics.nr_wakeups);
if (wake_flags & WF_SYNC)
- schedstat_inc(p, se.statistics.nr_wakeups_sync);
-
-#endif /* CONFIG_SCHEDSTATS */
+ schedstat_inc(p->se.statistics.nr_wakeups_sync);
}
static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags)
ttwu_queue(p, cpu, wake_flags);
stat:
- if (schedstat_enabled())
- ttwu_stat(p, cpu, wake_flags);
+ ttwu_stat(p, cpu, wake_flags);
out:
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
/**
* try_to_wake_up_local - try to wake up a local task with rq lock held
* @p: the thread to be awakened
+ * @cookie: context's cookie for pinning
*
* Put @p on the run-queue if it's not already there. The caller must
* ensure that this_rq() is locked, @p is bound to this_rq() and not
ttwu_activate(rq, p, ENQUEUE_WAKEUP);
ttwu_do_wakeup(rq, p, 0, cookie);
- if (schedstat_enabled())
- ttwu_stat(p, smp_processor_id(), 0);
+ ttwu_stat(p, smp_processor_id(), 0);
out:
raw_spin_unlock(&p->pi_lock);
}
*/
static noinline void __schedule_bug(struct task_struct *prev)
{
+ /* Save this before calling printk(), since that will clobber it */
+ unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
+
if (oops_in_progress)
return;
print_modules();
if (irqs_disabled())
print_irqtrace_events(prev);
-#ifdef CONFIG_DEBUG_PREEMPT
- if (in_atomic_preempt_off()) {
+ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+ && in_atomic_preempt_off()) {
pr_err("Preemption disabled at:");
- print_ip_sym(current->preempt_disable_ip);
+ print_ip_sym(preempt_disable_ip);
pr_cont("\n");
}
-#endif
if (panic_on_warn)
panic("scheduling while atomic\n");
profile_hit(SCHED_PROFILING, __builtin_return_address(0));
- schedstat_inc(this_rq(), sched_count);
+ schedstat_inc(this_rq()->sched_count);
}
/*
rq = cpu_rq(cpu);
prev = rq->curr;
- /*
- * do_exit() calls schedule() with preemption disabled as an exception;
- * however we must fix that up, otherwise the next task will see an
- * inconsistent (higher) preempt count.
- *
- * It also avoids the below schedule_debug() test from complaining
- * about this.
- */
- if (unlikely(prev->state == TASK_DEAD))
- preempt_enable_no_resched_notrace();
-
schedule_debug(prev);
if (sched_feat(HRTICK))
}
STACK_FRAME_NON_STANDARD(__schedule); /* switch_to() */
+void __noreturn do_task_dead(void)
+{
+ /*
+ * The setting of TASK_RUNNING by try_to_wake_up() may be delayed
+ * when the following two conditions become true.
+ * - There is race condition of mmap_sem (It is acquired by
+ * exit_mm()), and
+ * - SMI occurs before setting TASK_RUNINNG.
+ * (or hypervisor of virtual machine switches to other guest)
+ * As a result, we may become TASK_RUNNING after becoming TASK_DEAD
+ *
+ * To avoid it, we have to wait for releasing tsk->pi_lock which
+ * is held by try_to_wake_up()
+ */
+ smp_mb();
+ raw_spin_unlock_wait(¤t->pi_lock);
+
+ /* causes final put_task_struct in finish_task_switch(). */
+ __set_current_state(TASK_DEAD);
+ current->flags |= PF_NOFREEZE; /* tell freezer to ignore us */
+ __schedule(false);
+ BUG();
+ /* Avoid "noreturn function does return". */
+ for (;;)
+ cpu_relax(); /* For when BUG is null */
+}
+
static inline void sched_submit_work(struct task_struct *tsk)
{
if (!tsk->state || tsk_is_pi_blocked(tsk))
{
struct rq *rq = this_rq_lock();
- schedstat_inc(rq, yld_count);
+ schedstat_inc(rq->yld_count);
current->sched_class->yield_task(rq);
/*
return 0;
}
+#ifndef CONFIG_PREEMPT
int __sched _cond_resched(void)
{
if (should_resched(0)) {
return 0;
}
EXPORT_SYMBOL(_cond_resched);
+#endif
/*
* __cond_resched_lock() - if a reschedule is pending, drop the given lock,
yielded = curr->sched_class->yield_to_task(rq, p, preempt);
if (yielded) {
- schedstat_inc(rq, yld_count);
+ schedstat_inc(rq->yld_count);
/*
* Make p's CPU reschedule; pick_next_entity takes care of
* fairness.
}
}
#else /* !CONFIG_SCHED_DEBUG */
+
+# define sched_debug_enabled 0
# define sched_domain_debug(sd, cpu) do { } while (0)
static inline bool sched_debug(void)
{
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
SD_SHARE_CPUCAPACITY |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_SHARE_POWERDOMAIN)) {
if (sd->groups != sd->groups->next)
SD_BALANCE_NEWIDLE |
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_PREFER_SIBLING |
/*
* SD_flags allowed in topology descriptions.
*
- * SD_SHARE_CPUCAPACITY - describes SMT topologies
- * SD_SHARE_PKG_RESOURCES - describes shared caches
- * SD_NUMA - describes NUMA topologies
- * SD_SHARE_POWERDOMAIN - describes shared power domain
+ * These flags are purely descriptive of the topology and do not prescribe
+ * behaviour. Behaviour is artificial and mapped in the below sd_init()
+ * function:
*
- * Odd one out:
- * SD_ASYM_PACKING - describes SMT quirks
+ * SD_SHARE_CPUCAPACITY - describes SMT topologies
+ * SD_SHARE_PKG_RESOURCES - describes shared caches
+ * SD_NUMA - describes NUMA topologies
+ * SD_SHARE_POWERDOMAIN - describes shared power domain
+ * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies
+ *
+ * Odd one out, which beside describing the topology has a quirk also
+ * prescribes the desired behaviour that goes along with it:
+ *
+ * SD_ASYM_PACKING - describes SMT quirks
*/
#define TOPOLOGY_SD_FLAGS \
(SD_SHARE_CPUCAPACITY | \
SD_SHARE_PKG_RESOURCES | \
SD_NUMA | \
SD_ASYM_PACKING | \
+ SD_ASYM_CPUCAPACITY | \
SD_SHARE_POWERDOMAIN)
static struct sched_domain *
-sd_init(struct sched_domain_topology_level *tl, int cpu)
+sd_init(struct sched_domain_topology_level *tl,
+ struct sched_domain *child, int cpu)
{
struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu);
int sd_weight, sd_flags = 0;
.smt_gain = 0,
.max_newidle_lb_cost = 0,
.next_decay_max_lb_cost = jiffies,
+ .child = child,
#ifdef CONFIG_SCHED_DEBUG
.name = tl->name,
#endif
* Convert topological properties into behaviour.
*/
+ if (sd->flags & SD_ASYM_CPUCAPACITY) {
+ struct sched_domain *t = sd;
+
+ for_each_lower_domain(t)
+ t->flags |= SD_BALANCE_WAKE;
+ }
+
if (sd->flags & SD_SHARE_CPUCAPACITY) {
sd->flags |= SD_PREFER_SIBLING;
sd->imbalance_pct = 110;
const struct cpumask *cpu_map, struct sched_domain_attr *attr,
struct sched_domain *child, int cpu)
{
- struct sched_domain *sd = sd_init(tl, cpu);
- if (!sd)
- return child;
+ struct sched_domain *sd = sd_init(tl, child, cpu);
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
sd->level = child->level + 1;
sched_domain_level_max = max(sched_domain_level_max, sd->level);
child->parent = sd;
- sd->child = child;
if (!cpumask_subset(sched_domain_span(child),
sched_domain_span(sd))) {
enum s_alloc alloc_state;
struct sched_domain *sd;
struct s_data d;
+ struct rq *rq = NULL;
int i, ret = -ENOMEM;
alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
/* Attach the domains */
rcu_read_lock();
for_each_cpu(i, cpu_map) {
+ rq = cpu_rq(i);
sd = *per_cpu_ptr(d.sd, i);
+
+ /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */
+ if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity))
+ WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig);
+
cpu_attach_domain(sd, d.rd, i);
}
rcu_read_unlock();
+ if (rq && sched_debug_enabled) {
+ pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
+ cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
+ }
+
ret = 0;
error:
__free_domain_allocs(&d, alloc_state, cpu_map);
set_load_weight(&init_task);
-#ifdef CONFIG_PREEMPT_NOTIFIERS
- INIT_HLIST_HEAD(&init_task.preempt_notifiers);
-#endif
-
/*
* The boot idle thread does lazy MMU switching as well:
*/
atomic_inc(&init_mm.mm_count);
enter_lazy_tlb(&init_mm, current);
- /*
- * During early bootup we pretend to be a normal task:
- */
- current->sched_class = &fair_sched_class;
-
/*
* Make us the idle thread. Technically, schedule() should not be
* called from this thread, however somewhere below it might be,
void ___might_sleep(const char *file, int line, int preempt_offset)
{
static unsigned long prev_jiffy; /* ratelimiting */
+ unsigned long preempt_disable_ip;
rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
return;
prev_jiffy = jiffies;
+ /* Save this before calling printk(), since that will clobber it */
+ preempt_disable_ip = get_preempt_disable_ip(current);
+
printk(KERN_ERR
"BUG: sleeping function called from invalid context at %s:%d\n",
file, line);
debug_show_held_locks(current);
if (irqs_disabled())
print_irqtrace_events(current);
-#ifdef CONFIG_DEBUG_PREEMPT
- if (!preempt_count_equals(preempt_offset)) {
+ if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+ && !preempt_count_equals(preempt_offset)) {
pr_err("Preemption disabled at:");
- print_ip_sym(current->preempt_disable_ip);
+ print_ip_sym(preempt_disable_ip);
pr_cont("\n");
}
-#endif
dump_stack();
+ add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
}
EXPORT_SYMBOL(___might_sleep);
#endif
if (p->flags & PF_KTHREAD)
continue;
- p->se.exec_start = 0;
-#ifdef CONFIG_SCHEDSTATS
- p->se.statistics.wait_start = 0;
- p->se.statistics.sleep_start = 0;
- p->se.statistics.block_start = 0;
-#endif
+ p->se.exec_start = 0;
+ schedstat_set(p->se.statistics.wait_start, 0);
+ schedstat_set(p->se.statistics.sleep_start, 0);
+ schedstat_set(p->se.statistics.block_start, 0);
if (!dl_task(p) && !rt_task(p)) {
/*
return (i << 1) + 2;
}
-static void cpudl_exchange(struct cpudl *cp, int a, int b)
+static void cpudl_heapify_down(struct cpudl *cp, int idx)
{
- int cpu_a = cp->elements[a].cpu, cpu_b = cp->elements[b].cpu;
+ int l, r, largest;
- swap(cp->elements[a].cpu, cp->elements[b].cpu);
- swap(cp->elements[a].dl , cp->elements[b].dl );
+ int orig_cpu = cp->elements[idx].cpu;
+ u64 orig_dl = cp->elements[idx].dl;
- swap(cp->elements[cpu_a].idx, cp->elements[cpu_b].idx);
-}
-
-static void cpudl_heapify(struct cpudl *cp, int idx)
-{
- int l, r, largest;
+ if (left_child(idx) >= cp->size)
+ return;
/* adapted from lib/prio_heap.c */
while(1) {
+ u64 largest_dl;
l = left_child(idx);
r = right_child(idx);
largest = idx;
+ largest_dl = orig_dl;
- if ((l < cp->size) && dl_time_before(cp->elements[idx].dl,
- cp->elements[l].dl))
+ if ((l < cp->size) && dl_time_before(orig_dl,
+ cp->elements[l].dl)) {
largest = l;
- if ((r < cp->size) && dl_time_before(cp->elements[largest].dl,
- cp->elements[r].dl))
+ largest_dl = cp->elements[l].dl;
+ }
+ if ((r < cp->size) && dl_time_before(largest_dl,
+ cp->elements[r].dl))
largest = r;
+
if (largest == idx)
break;
- /* Push idx down the heap one level and bump one up */
- cpudl_exchange(cp, largest, idx);
+ /* pull largest child onto idx */
+ cp->elements[idx].cpu = cp->elements[largest].cpu;
+ cp->elements[idx].dl = cp->elements[largest].dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
idx = largest;
}
+ /* actual push down of saved original values orig_* */
+ cp->elements[idx].cpu = orig_cpu;
+ cp->elements[idx].dl = orig_dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
}
-static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
+static void cpudl_heapify_up(struct cpudl *cp, int idx)
{
- WARN_ON(idx == IDX_INVALID || !cpu_present(idx));
+ int p;
- if (dl_time_before(new_dl, cp->elements[idx].dl)) {
- cp->elements[idx].dl = new_dl;
- cpudl_heapify(cp, idx);
- } else {
- cp->elements[idx].dl = new_dl;
- while (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
- cp->elements[idx].dl)) {
- cpudl_exchange(cp, idx, parent(idx));
- idx = parent(idx);
- }
- }
+ int orig_cpu = cp->elements[idx].cpu;
+ u64 orig_dl = cp->elements[idx].dl;
+
+ if (idx == 0)
+ return;
+
+ do {
+ p = parent(idx);
+ if (dl_time_before(orig_dl, cp->elements[p].dl))
+ break;
+ /* pull parent onto idx */
+ cp->elements[idx].cpu = cp->elements[p].cpu;
+ cp->elements[idx].dl = cp->elements[p].dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
+ idx = p;
+ } while (idx != 0);
+ /* actual push up of saved original values orig_* */
+ cp->elements[idx].cpu = orig_cpu;
+ cp->elements[idx].dl = orig_dl;
+ cp->elements[cp->elements[idx].cpu].idx = idx;
+}
+
+static void cpudl_heapify(struct cpudl *cp, int idx)
+{
+ if (idx > 0 && dl_time_before(cp->elements[parent(idx)].dl,
+ cp->elements[idx].dl))
+ cpudl_heapify_up(cp, idx);
+ else
+ cpudl_heapify_down(cp, idx);
}
static inline int cpudl_maximum(struct cpudl *cp)
}
/*
- * cpudl_set - update the cpudl max-heap
+ * cpudl_clear - remove a cpu from the cpudl max-heap
* @cp: the cpudl max-heap context
* @cpu: the target cpu
- * @dl: the new earliest deadline for this cpu
*
* Notes: assumes cpu_rq(cpu)->lock is locked
*
* Returns: (void)
*/
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
+void cpudl_clear(struct cpudl *cp, int cpu)
{
int old_idx, new_cpu;
unsigned long flags;
WARN_ON(!cpu_present(cpu));
raw_spin_lock_irqsave(&cp->lock, flags);
+
old_idx = cp->elements[cpu].idx;
- if (!is_valid) {
- /* remove item */
- if (old_idx == IDX_INVALID) {
- /*
- * Nothing to remove if old_idx was invalid.
- * This could happen if a rq_offline_dl is
- * called for a CPU without -dl tasks running.
- */
- goto out;
- }
+ if (old_idx == IDX_INVALID) {
+ /*
+ * Nothing to remove if old_idx was invalid.
+ * This could happen if a rq_offline_dl is
+ * called for a CPU without -dl tasks running.
+ */
+ } else {
new_cpu = cp->elements[cp->size - 1].cpu;
cp->elements[old_idx].dl = cp->elements[cp->size - 1].dl;
cp->elements[old_idx].cpu = new_cpu;
cp->size--;
cp->elements[new_cpu].idx = old_idx;
cp->elements[cpu].idx = IDX_INVALID;
- while (old_idx > 0 && dl_time_before(
- cp->elements[parent(old_idx)].dl,
- cp->elements[old_idx].dl)) {
- cpudl_exchange(cp, old_idx, parent(old_idx));
- old_idx = parent(old_idx);
- }
- cpumask_set_cpu(cpu, cp->free_cpus);
- cpudl_heapify(cp, old_idx);
+ cpudl_heapify(cp, old_idx);
- goto out;
+ cpumask_set_cpu(cpu, cp->free_cpus);
}
+ raw_spin_unlock_irqrestore(&cp->lock, flags);
+}
+
+/*
+ * cpudl_set - update the cpudl max-heap
+ * @cp: the cpudl max-heap context
+ * @cpu: the target cpu
+ * @dl: the new earliest deadline for this cpu
+ *
+ * Notes: assumes cpu_rq(cpu)->lock is locked
+ *
+ * Returns: (void)
+ */
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl)
+{
+ int old_idx;
+ unsigned long flags;
+ WARN_ON(!cpu_present(cpu));
+
+ raw_spin_lock_irqsave(&cp->lock, flags);
+
+ old_idx = cp->elements[cpu].idx;
if (old_idx == IDX_INVALID) {
- cp->size++;
- cp->elements[cp->size - 1].dl = dl;
- cp->elements[cp->size - 1].cpu = cpu;
- cp->elements[cpu].idx = cp->size - 1;
- cpudl_change_key(cp, cp->size - 1, dl);
+ int new_idx = cp->size++;
+ cp->elements[new_idx].dl = dl;
+ cp->elements[new_idx].cpu = cpu;
+ cp->elements[cpu].idx = new_idx;
+ cpudl_heapify_up(cp, new_idx);
cpumask_clear_cpu(cpu, cp->free_cpus);
} else {
- cpudl_change_key(cp, old_idx, dl);
+ cp->elements[old_idx].dl = dl;
+ cpudl_heapify(cp, old_idx);
}
-out:
raw_spin_unlock_irqrestore(&cp->lock, flags);
}
#ifdef CONFIG_SMP
int cpudl_find(struct cpudl *cp, struct task_struct *p,
struct cpumask *later_mask);
-void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid);
+void cpudl_set(struct cpudl *cp, int cpu, u64 dl);
+void cpudl_clear(struct cpudl *cp, int cpu);
int cpudl_init(struct cpudl *cp);
void cpudl_set_freecpu(struct cpudl *cp, int cpu);
void cpudl_clear_freecpu(struct cpudl *cp, int cpu);
return accounted;
}
+#ifdef CONFIG_64BIT
+static inline u64 read_sum_exec_runtime(struct task_struct *t)
+{
+ return t->se.sum_exec_runtime;
+}
+#else
+static u64 read_sum_exec_runtime(struct task_struct *t)
+{
+ u64 ns;
+ struct rq_flags rf;
+ struct rq *rq;
+
+ rq = task_rq_lock(t, &rf);
+ ns = t->se.sum_exec_runtime;
+ task_rq_unlock(rq, t, &rf);
+
+ return ns;
+}
+#endif
+
/*
* Accumulate raw cputime values of dead tasks (sig->[us]time) and live
* tasks (sum on group iteration) belonging to @tsk's group.
unsigned int seq, nextseq;
unsigned long flags;
+ /*
+ * Update current task runtime to account pending time since last
+ * scheduler action or thread_group_cputime() call. This thread group
+ * might have other running tasks on different CPUs, but updating
+ * their runtime can affect syscall performance, so we skip account
+ * those pending times and rely only on values updated on tick or
+ * other scheduler action.
+ */
+ if (same_thread_group(current, tsk))
+ (void) task_sched_runtime(current);
+
rcu_read_lock();
/* Attempt a lockless read on the first round. */
nextseq = 0;
task_cputime(t, &utime, &stime);
times->utime += utime;
times->stime += stime;
- times->sum_exec_runtime += task_sched_runtime(t);
+ times->sum_exec_runtime += read_sum_exec_runtime(t);
}
/* If lockless access failed, take the lock. */
nextseq = 1;
static struct rq *dl_task_offline_migration(struct rq *rq, struct task_struct *p)
{
struct rq *later_rq = NULL;
- bool fallback = false;
later_rq = find_lock_later_rq(p, rq);
-
if (!later_rq) {
int cpu;
* If we cannot preempt any rq, fall back to pick any
* online cpu.
*/
- fallback = true;
cpu = cpumask_any_and(cpu_active_mask, tsk_cpus_allowed(p));
if (cpu >= nr_cpu_ids) {
/*
double_lock_balance(rq, later_rq);
}
- /*
- * By now the task is replenished and enqueued; migrate it.
- */
- deactivate_task(rq, p, 0);
set_task_cpu(p, later_rq->cpu);
- activate_task(later_rq, p, 0);
-
- if (!fallback)
- resched_curr(later_rq);
-
double_unlock_balance(later_rq, rq);
return later_rq;
* one, and to (try to!) reconcile itself with its own scheduling
* parameters.
*/
-static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se,
- struct sched_dl_entity *pi_se)
+static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
{
struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
struct rq *rq = rq_of_dl_rq(dl_rq);
+ WARN_ON(dl_se->dl_boosted);
WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
/*
* future; in fact, we must consider execution overheads (time
* spent on hardirq context, etc.).
*/
- dl_se->deadline = rq_clock(rq) + pi_se->dl_deadline;
- dl_se->runtime = pi_se->dl_runtime;
+ dl_se->deadline = rq_clock(rq) + dl_se->dl_deadline;
+ dl_se->runtime = dl_se->dl_runtime;
}
/*
goto unlock;
}
- enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
- if (dl_task(rq->curr))
- check_preempt_curr_dl(rq, p, 0);
- else
- resched_curr(rq);
-
#ifdef CONFIG_SMP
- /*
- * Perform balancing operations here; after the replenishments. We
- * cannot drop rq->lock before this, otherwise the assertion in
- * start_dl_timer() about not missing updates is not true.
- *
- * If we find that the rq the task was on is no longer available, we
- * need to select a new rq.
- *
- * XXX figure out if select_task_rq_dl() deals with offline cpus.
- */
if (unlikely(!rq->online)) {
+ /*
+ * If the runqueue is no longer available, migrate the
+ * task elsewhere. This necessarily changes rq.
+ */
lockdep_unpin_lock(&rq->lock, rf.cookie);
rq = dl_task_offline_migration(rq, p);
rf.cookie = lockdep_pin_lock(&rq->lock);
+
+ /*
+ * Now that the task has been migrated to the new RQ and we
+ * have that locked, proceed as normal and enqueue the task
+ * there.
+ */
}
+#endif
+
+ enqueue_task_dl(rq, p, ENQUEUE_REPLENISH);
+ if (dl_task(rq->curr))
+ check_preempt_curr_dl(rq, p, 0);
+ else
+ resched_curr(rq);
+#ifdef CONFIG_SMP
/*
* Queueing this task back might have overloaded rq, check if we need
* to kick someone away.
if (dl_rq->earliest_dl.curr == 0 ||
dl_time_before(deadline, dl_rq->earliest_dl.curr)) {
dl_rq->earliest_dl.curr = deadline;
- cpudl_set(&rq->rd->cpudl, rq->cpu, deadline, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, deadline);
}
}
if (!dl_rq->dl_nr_running) {
dl_rq->earliest_dl.curr = 0;
dl_rq->earliest_dl.next = 0;
- cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+ cpudl_clear(&rq->rd->cpudl, rq->cpu);
} else {
struct rb_node *leftmost = dl_rq->rb_leftmost;
struct sched_dl_entity *entry;
entry = rb_entry(leftmost, struct sched_dl_entity, rb_node);
dl_rq->earliest_dl.curr = entry->deadline;
- cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, entry->deadline);
}
}
cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);
if (rq->dl.dl_nr_running > 0)
- cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr, 1);
+ cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr);
}
/* Assumes rq->lock is held */
if (rq->dl.overloaded)
dl_clear_overload(rq);
- cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);
+ cpudl_clear(&rq->rd->cpudl, rq->cpu);
cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);
}
*/
static void switched_to_dl(struct rq *rq, struct task_struct *p)
{
+
+ /* If p is not queued we will update its parameters at next wakeup. */
+ if (!task_on_rq_queued(p))
+ return;
+
+ /*
+ * If p is boosted we already updated its params in
+ * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
+ * p's deadline being now already after rq_clock(rq).
+ */
if (dl_time_before(p->dl.deadline, rq_clock(rq)))
- setup_new_dl_entity(&p->dl, &p->dl);
+ setup_new_dl_entity(&p->dl);
- if (task_on_rq_queued(p) && rq->curr != p) {
+ if (rq->curr != p) {
#ifdef CONFIG_SMP
if (tsk_nr_cpus_allowed(p) > 1 && rq->dl.overloaded)
queue_push_tasks(rq);
#define P(F) \
SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)F)
+#define P_SCHEDSTAT(F) \
+ SEQ_printf(m, " .%-30s: %lld\n", #F, (long long)schedstat_val(F))
#define PN(F) \
SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)F))
+#define PN_SCHEDSTAT(F) \
+ SEQ_printf(m, " .%-30s: %lld.%06ld\n", #F, SPLIT_NS((long long)schedstat_val(F)))
if (!se)
return;
PN(se->exec_start);
PN(se->vruntime);
PN(se->sum_exec_runtime);
-#ifdef CONFIG_SCHEDSTATS
if (schedstat_enabled()) {
- PN(se->statistics.wait_start);
- PN(se->statistics.sleep_start);
- PN(se->statistics.block_start);
- PN(se->statistics.sleep_max);
- PN(se->statistics.block_max);
- PN(se->statistics.exec_max);
- PN(se->statistics.slice_max);
- PN(se->statistics.wait_max);
- PN(se->statistics.wait_sum);
- P(se->statistics.wait_count);
+ PN_SCHEDSTAT(se->statistics.wait_start);
+ PN_SCHEDSTAT(se->statistics.sleep_start);
+ PN_SCHEDSTAT(se->statistics.block_start);
+ PN_SCHEDSTAT(se->statistics.sleep_max);
+ PN_SCHEDSTAT(se->statistics.block_max);
+ PN_SCHEDSTAT(se->statistics.exec_max);
+ PN_SCHEDSTAT(se->statistics.slice_max);
+ PN_SCHEDSTAT(se->statistics.wait_max);
+ PN_SCHEDSTAT(se->statistics.wait_sum);
+ P_SCHEDSTAT(se->statistics.wait_count);
}
-#endif
P(se->load.weight);
#ifdef CONFIG_SMP
P(se->avg.load_avg);
P(se->avg.util_avg);
#endif
+
+#undef PN_SCHEDSTAT
#undef PN
+#undef P_SCHEDSTAT
#undef P
}
#endif
p->prio);
SEQ_printf(m, "%9Ld.%06ld %9Ld.%06ld %9Ld.%06ld",
- SPLIT_NS(schedstat_val(p, se.statistics.wait_sum)),
+ SPLIT_NS(schedstat_val_or_zero(p->se.statistics.wait_sum)),
SPLIT_NS(p->se.sum_exec_runtime),
- SPLIT_NS(schedstat_val(p, se.statistics.sum_sleep_runtime)));
+ SPLIT_NS(schedstat_val_or_zero(p->se.statistics.sum_sleep_runtime)));
#ifdef CONFIG_NUMA_BALANCING
SEQ_printf(m, " %d %d", task_node(p), task_numa_group_id(p));
#undef P64
#endif
-#ifdef CONFIG_SCHEDSTATS
-#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, rq->n);
-
+#define P(n) SEQ_printf(m, " .%-30s: %d\n", #n, schedstat_val(rq->n));
if (schedstat_enabled()) {
P(yld_count);
P(sched_count);
P(ttwu_count);
P(ttwu_local);
}
-
#undef P
-#endif
+
spin_lock_irqsave(&sched_debug_lock, flags);
print_cfs_stats(m, cpu);
print_rt_stats(m, cpu);
SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)F)
#define P(F) \
SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)p->F)
+#define P_SCHEDSTAT(F) \
+ SEQ_printf(m, "%-45s:%21Ld\n", #F, (long long)schedstat_val(p->F))
#define __PN(F) \
SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)F))
#define PN(F) \
SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)p->F))
+#define PN_SCHEDSTAT(F) \
+ SEQ_printf(m, "%-45s:%14Ld.%06ld\n", #F, SPLIT_NS((long long)schedstat_val(p->F)))
PN(se.exec_start);
PN(se.vruntime);
P(se.nr_migrations);
-#ifdef CONFIG_SCHEDSTATS
if (schedstat_enabled()) {
u64 avg_atom, avg_per_cpu;
- PN(se.statistics.sum_sleep_runtime);
- PN(se.statistics.wait_start);
- PN(se.statistics.sleep_start);
- PN(se.statistics.block_start);
- PN(se.statistics.sleep_max);
- PN(se.statistics.block_max);
- PN(se.statistics.exec_max);
- PN(se.statistics.slice_max);
- PN(se.statistics.wait_max);
- PN(se.statistics.wait_sum);
- P(se.statistics.wait_count);
- PN(se.statistics.iowait_sum);
- P(se.statistics.iowait_count);
- P(se.statistics.nr_migrations_cold);
- P(se.statistics.nr_failed_migrations_affine);
- P(se.statistics.nr_failed_migrations_running);
- P(se.statistics.nr_failed_migrations_hot);
- P(se.statistics.nr_forced_migrations);
- P(se.statistics.nr_wakeups);
- P(se.statistics.nr_wakeups_sync);
- P(se.statistics.nr_wakeups_migrate);
- P(se.statistics.nr_wakeups_local);
- P(se.statistics.nr_wakeups_remote);
- P(se.statistics.nr_wakeups_affine);
- P(se.statistics.nr_wakeups_affine_attempts);
- P(se.statistics.nr_wakeups_passive);
- P(se.statistics.nr_wakeups_idle);
+ PN_SCHEDSTAT(se.statistics.sum_sleep_runtime);
+ PN_SCHEDSTAT(se.statistics.wait_start);
+ PN_SCHEDSTAT(se.statistics.sleep_start);
+ PN_SCHEDSTAT(se.statistics.block_start);
+ PN_SCHEDSTAT(se.statistics.sleep_max);
+ PN_SCHEDSTAT(se.statistics.block_max);
+ PN_SCHEDSTAT(se.statistics.exec_max);
+ PN_SCHEDSTAT(se.statistics.slice_max);
+ PN_SCHEDSTAT(se.statistics.wait_max);
+ PN_SCHEDSTAT(se.statistics.wait_sum);
+ P_SCHEDSTAT(se.statistics.wait_count);
+ PN_SCHEDSTAT(se.statistics.iowait_sum);
+ P_SCHEDSTAT(se.statistics.iowait_count);
+ P_SCHEDSTAT(se.statistics.nr_migrations_cold);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_affine);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_running);
+ P_SCHEDSTAT(se.statistics.nr_failed_migrations_hot);
+ P_SCHEDSTAT(se.statistics.nr_forced_migrations);
+ P_SCHEDSTAT(se.statistics.nr_wakeups);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_sync);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_migrate);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_local);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_remote);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_affine);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_affine_attempts);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_passive);
+ P_SCHEDSTAT(se.statistics.nr_wakeups_idle);
avg_atom = p->se.sum_exec_runtime;
if (nr_switches)
__PN(avg_atom);
__PN(avg_per_cpu);
}
-#endif
+
__P(nr_switches);
SEQ_printf(m, "%-45s:%21Ld\n",
"nr_voluntary_switches", (long long)p->nvcsw);
#endif
P(policy);
P(prio);
+#undef PN_SCHEDSTAT
#undef PN
#undef __PN
+#undef P_SCHEDSTAT
#undef P
#undef __P
unsigned int sysctl_sched_cfs_bandwidth_slice = 5000UL;
#endif
+/*
+ * The margin used when comparing utilization with CPU capacity:
+ * util * 1024 < capacity * margin
+ */
+unsigned int capacity_margin = 1280; /* ~20% */
+
static inline void update_load_add(struct load_weight *lw, unsigned long inc)
{
lw->weight += inc;
}
#ifdef CONFIG_SMP
-static int select_idle_sibling(struct task_struct *p, int cpu);
+static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
static unsigned long task_h_load(struct task_struct *p);
/*
struct sched_avg *sa = &se->avg;
long cap = (long)(SCHED_CAPACITY_SCALE - cfs_rq->avg.util_avg) / 2;
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
if (cap > 0) {
if (cfs_rq->avg.util_avg != 0) {
}
}
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
attach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
}
#else /* !CONFIG_SMP */
max(delta_exec, curr->statistics.exec_max));
curr->sum_exec_runtime += delta_exec;
- schedstat_add(cfs_rq, exec_clock, delta_exec);
+ schedstat_add(cfs_rq->exec_clock, delta_exec);
curr->vruntime += calc_delta_fair(delta_exec, curr);
update_min_vruntime(cfs_rq);
update_curr(cfs_rq_of(&rq->curr->se));
}
-#ifdef CONFIG_SCHEDSTATS
static inline void
update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- u64 wait_start = rq_clock(rq_of(cfs_rq));
+ u64 wait_start, prev_wait_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ wait_start = rq_clock(rq_of(cfs_rq));
+ prev_wait_start = schedstat_val(se->statistics.wait_start);
if (entity_is_task(se) && task_on_rq_migrating(task_of(se)) &&
- likely(wait_start > se->statistics.wait_start))
- wait_start -= se->statistics.wait_start;
+ likely(wait_start > prev_wait_start))
+ wait_start -= prev_wait_start;
- se->statistics.wait_start = wait_start;
+ schedstat_set(se->statistics.wait_start, wait_start);
}
-static void
+static inline void
update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
struct task_struct *p;
u64 delta;
- delta = rq_clock(rq_of(cfs_rq)) - se->statistics.wait_start;
+ if (!schedstat_enabled())
+ return;
+
+ delta = rq_clock(rq_of(cfs_rq)) - schedstat_val(se->statistics.wait_start);
if (entity_is_task(se)) {
p = task_of(se);
* time stamp can be adjusted to accumulate wait time
* prior to migration.
*/
- se->statistics.wait_start = delta;
+ schedstat_set(se->statistics.wait_start, delta);
return;
}
trace_sched_stat_wait(p, delta);
}
- se->statistics.wait_max = max(se->statistics.wait_max, delta);
- se->statistics.wait_count++;
- se->statistics.wait_sum += delta;
- se->statistics.wait_start = 0;
+ schedstat_set(se->statistics.wait_max,
+ max(schedstat_val(se->statistics.wait_max), delta));
+ schedstat_inc(se->statistics.wait_count);
+ schedstat_add(se->statistics.wait_sum, delta);
+ schedstat_set(se->statistics.wait_start, 0);
+}
+
+static inline void
+update_stats_enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ struct task_struct *tsk = NULL;
+ u64 sleep_start, block_start;
+
+ if (!schedstat_enabled())
+ return;
+
+ sleep_start = schedstat_val(se->statistics.sleep_start);
+ block_start = schedstat_val(se->statistics.block_start);
+
+ if (entity_is_task(se))
+ tsk = task_of(se);
+
+ if (sleep_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - sleep_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.sleep_max)))
+ schedstat_set(se->statistics.sleep_max, delta);
+
+ schedstat_set(se->statistics.sleep_start, 0);
+ schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ account_scheduler_latency(tsk, delta >> 10, 1);
+ trace_sched_stat_sleep(tsk, delta);
+ }
+ }
+ if (block_start) {
+ u64 delta = rq_clock(rq_of(cfs_rq)) - block_start;
+
+ if ((s64)delta < 0)
+ delta = 0;
+
+ if (unlikely(delta > schedstat_val(se->statistics.block_max)))
+ schedstat_set(se->statistics.block_max, delta);
+
+ schedstat_set(se->statistics.block_start, 0);
+ schedstat_add(se->statistics.sum_sleep_runtime, delta);
+
+ if (tsk) {
+ if (tsk->in_iowait) {
+ schedstat_add(se->statistics.iowait_sum, delta);
+ schedstat_inc(se->statistics.iowait_count);
+ trace_sched_stat_iowait(tsk, delta);
+ }
+
+ trace_sched_stat_blocked(tsk, delta);
+
+ /*
+ * Blocking time is in units of nanosecs, so shift by
+ * 20 to get a milliseconds-range estimation of the
+ * amount of time that the task spent sleeping:
+ */
+ if (unlikely(prof_on == SLEEP_PROFILING)) {
+ profile_hits(SLEEP_PROFILING,
+ (void *)get_wchan(tsk),
+ delta >> 20);
+ }
+ account_scheduler_latency(tsk, delta >> 10, 0);
+ }
+ }
}
/*
* Task is being enqueued - update stats:
*/
static inline void
-update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
+update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+ if (!schedstat_enabled())
+ return;
+
/*
* Are we enqueueing a waiting task? (for current tasks
* a dequeue/enqueue event is a NOP)
*/
if (se != cfs_rq->curr)
update_stats_wait_start(cfs_rq, se);
+
+ if (flags & ENQUEUE_WAKEUP)
+ update_stats_enqueue_sleeper(cfs_rq, se);
}
static inline void
update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
+
+ if (!schedstat_enabled())
+ return;
+
/*
* Mark the end of the wait period if dequeueing a
* waiting task:
if (se != cfs_rq->curr)
update_stats_wait_end(cfs_rq, se);
- if (flags & DEQUEUE_SLEEP) {
- if (entity_is_task(se)) {
- struct task_struct *tsk = task_of(se);
+ if ((flags & DEQUEUE_SLEEP) && entity_is_task(se)) {
+ struct task_struct *tsk = task_of(se);
- if (tsk->state & TASK_INTERRUPTIBLE)
- se->statistics.sleep_start = rq_clock(rq_of(cfs_rq));
- if (tsk->state & TASK_UNINTERRUPTIBLE)
- se->statistics.block_start = rq_clock(rq_of(cfs_rq));
- }
+ if (tsk->state & TASK_INTERRUPTIBLE)
+ schedstat_set(se->statistics.sleep_start,
+ rq_clock(rq_of(cfs_rq)));
+ if (tsk->state & TASK_UNINTERRUPTIBLE)
+ schedstat_set(se->statistics.block_start,
+ rq_clock(rq_of(cfs_rq)));
}
-
-}
-#else
-static inline void
-update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
}
-static inline void
-update_stats_wait_end(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-}
-
-static inline void
-update_stats_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-}
-
-static inline void
-update_stats_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
-{
-}
-#endif
-
/*
* We are picking a new current task - update its stats:
*/
* Call select_idle_sibling to maybe find a better one.
*/
if (!cur)
- env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu);
+ env->dst_cpu = select_idle_sibling(env->p, env->src_cpu,
+ env->dst_cpu);
assign:
task_numa_assign(env, cur, imp);
}
#ifdef CONFIG_FAIR_GROUP_SCHED
-/*
- * Updating tg's load_avg is necessary before update_cfs_share (which is done)
- * and effective_load (which is not done because it is too costly).
+/**
+ * update_tg_load_avg - update the tg's load avg
+ * @cfs_rq: the cfs_rq whose avg changed
+ * @force: update regardless of how small the difference
+ *
+ * This function 'ensures': tg->load_avg := \Sum tg->cfs_rq[]->avg.load.
+ * However, because tg->load_avg is a global value there are performance
+ * considerations.
+ *
+ * In order to avoid having to look at the other cfs_rq's, we use a
+ * differential update where we store the last value we propagated. This in
+ * turn allows skipping updates if the differential is 'small'.
+ *
+ * Updating tg's load_avg is necessary before update_cfs_share() (which is
+ * done) and effective_load() (which is not done because it is too costly).
*/
static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
{
*
* cfs_rq->avg is used for task_h_load() and update_cfs_share() for example.
*
- * Returns true if the load decayed or we removed utilization. It is expected
- * that one calls update_tg_load_avg() on this condition, but after you've
- * modified the cfs_rq avg (attach/detach), such that we propagate the new
- * avg up.
+ * Returns true if the load decayed or we removed load.
+ *
+ * Since both these conditions indicate a changed cfs_rq->avg.load we should
+ * call update_tg_load_avg() when this function returns true.
*/
static inline int
update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
#endif /* CONFIG_SMP */
-static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
-{
-#ifdef CONFIG_SCHEDSTATS
- struct task_struct *tsk = NULL;
-
- if (entity_is_task(se))
- tsk = task_of(se);
-
- if (se->statistics.sleep_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.sleep_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.sleep_max))
- se->statistics.sleep_max = delta;
-
- se->statistics.sleep_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- account_scheduler_latency(tsk, delta >> 10, 1);
- trace_sched_stat_sleep(tsk, delta);
- }
- }
- if (se->statistics.block_start) {
- u64 delta = rq_clock(rq_of(cfs_rq)) - se->statistics.block_start;
-
- if ((s64)delta < 0)
- delta = 0;
-
- if (unlikely(delta > se->statistics.block_max))
- se->statistics.block_max = delta;
-
- se->statistics.block_start = 0;
- se->statistics.sum_sleep_runtime += delta;
-
- if (tsk) {
- if (tsk->in_iowait) {
- se->statistics.iowait_sum += delta;
- se->statistics.iowait_count++;
- trace_sched_stat_iowait(tsk, delta);
- }
-
- trace_sched_stat_blocked(tsk, delta);
-
- /*
- * Blocking time is in units of nanosecs, so shift by
- * 20 to get a milliseconds-range estimation of the
- * amount of time that the task spent sleeping:
- */
- if (unlikely(prof_on == SLEEP_PROFILING)) {
- profile_hits(SLEEP_PROFILING,
- (void *)get_wchan(tsk),
- delta >> 20);
- }
- account_scheduler_latency(tsk, delta >> 10, 0);
- }
- }
-#endif
-}
-
static void check_spread(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
#ifdef CONFIG_SCHED_DEBUG
d = -d;
if (d > 3*sysctl_sched_latency)
- schedstat_inc(cfs_rq, nr_spread_over);
+ schedstat_inc(cfs_rq->nr_spread_over);
#endif
}
account_entity_enqueue(cfs_rq, se);
update_cfs_shares(cfs_rq);
- if (flags & ENQUEUE_WAKEUP) {
+ if (flags & ENQUEUE_WAKEUP)
place_entity(cfs_rq, se, 0);
- if (schedstat_enabled())
- enqueue_sleeper(cfs_rq, se);
- }
check_schedstat_required();
- if (schedstat_enabled()) {
- update_stats_enqueue(cfs_rq, se);
- check_spread(cfs_rq, se);
- }
+ update_stats_enqueue(cfs_rq, se, flags);
+ check_spread(cfs_rq, se);
if (!curr)
__enqueue_entity(cfs_rq, se);
se->on_rq = 1;
update_curr(cfs_rq);
dequeue_entity_load_avg(cfs_rq, se);
- if (schedstat_enabled())
- update_stats_dequeue(cfs_rq, se, flags);
+ update_stats_dequeue(cfs_rq, se, flags);
clear_buddies(cfs_rq, se);
* a CPU. So account for the time it spent waiting on the
* runqueue.
*/
- if (schedstat_enabled())
- update_stats_wait_end(cfs_rq, se);
+ update_stats_wait_end(cfs_rq, se);
__dequeue_entity(cfs_rq, se);
update_load_avg(se, 1);
}
update_stats_curr_start(cfs_rq, se);
cfs_rq->curr = se;
-#ifdef CONFIG_SCHEDSTATS
+
/*
* Track our maximum slice length, if the CPU's load is at
* least twice that of our own weight (i.e. dont track it
* when there are only lesser-weight tasks around):
*/
if (schedstat_enabled() && rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
- se->statistics.slice_max = max(se->statistics.slice_max,
- se->sum_exec_runtime - se->prev_sum_exec_runtime);
+ schedstat_set(se->statistics.slice_max,
+ max((u64)schedstat_val(se->statistics.slice_max),
+ se->sum_exec_runtime - se->prev_sum_exec_runtime));
}
-#endif
+
se->prev_sum_exec_runtime = se->sum_exec_runtime;
}
/* throttle cfs_rqs exceeding runtime */
check_cfs_rq_runtime(cfs_rq);
- if (schedstat_enabled()) {
- check_spread(cfs_rq, prev);
- if (prev->on_rq)
- update_stats_wait_start(cfs_rq, prev);
- }
+ check_spread(cfs_rq, prev);
if (prev->on_rq) {
+ update_stats_wait_start(cfs_rq, prev);
/* Put 'current' back into the tree. */
__enqueue_entity(cfs_rq, prev);
/* in !on_rq case, update occurred at dequeue */
WARN_ON(task_rq(p) != rq);
- if (cfs_rq->nr_running > 1) {
+ if (rq->cfs.h_nr_running > 1) {
u64 slice = sched_slice(cfs_rq, se);
u64 ran = se->sum_exec_runtime - se->prev_sum_exec_runtime;
s64 delta = slice - ran;
return 1;
}
-static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
+static int wake_affine(struct sched_domain *sd, struct task_struct *p,
+ int prev_cpu, int sync)
{
s64 this_load, load;
s64 this_eff_load, prev_eff_load;
- int idx, this_cpu, prev_cpu;
+ int idx, this_cpu;
struct task_group *tg;
unsigned long weight;
int balanced;
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);
balanced = this_eff_load <= prev_eff_load;
- schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
+ schedstat_inc(p->se.statistics.nr_wakeups_affine_attempts);
if (!balanced)
return 0;
- schedstat_inc(sd, ttwu_move_affine);
- schedstat_inc(p, se.statistics.nr_wakeups_affine);
+ schedstat_inc(sd->ttwu_move_affine);
+ schedstat_inc(p->se.statistics.nr_wakeups_affine);
return 1;
}
int shallowest_idle_cpu = -1;
int i;
+ /* Check if we have any choice: */
+ if (group->group_weight == 1)
+ return cpumask_first(sched_group_cpus(group));
+
/* Traverse only the allowed CPUs */
for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
if (idle_cpu(i)) {
/*
* Try and locate an idle CPU in the sched_domain.
*/
-static int select_idle_sibling(struct task_struct *p, int target)
+static int select_idle_sibling(struct task_struct *p, int prev, int target)
{
struct sched_domain *sd;
struct sched_group *sg;
- int i = task_cpu(p);
if (idle_cpu(target))
return target;
/*
* If the prevous cpu is cache affine and idle, don't be stupid.
*/
- if (i != target && cpus_share_cache(i, target) && idle_cpu(i))
- return i;
+ if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev))
+ return prev;
/*
* Otherwise, iterate the domains and find an eligible idle cpu.
for_each_lower_domain(sd) {
sg = sd->groups;
do {
+ int i;
+
if (!cpumask_intersects(sched_group_cpus(sg),
tsk_cpus_allowed(p)))
goto next;
return (util >= capacity) ? capacity : util;
}
+static inline int task_util(struct task_struct *p)
+{
+ return p->se.avg.util_avg;
+}
+
+/*
+ * Disable WAKE_AFFINE in the case where task @p doesn't fit in the
+ * capacity of either the waking CPU @cpu or the previous CPU @prev_cpu.
+ *
+ * In that case WAKE_AFFINE doesn't make sense and we'll let
+ * BALANCE_WAKE sort things out.
+ */
+static int wake_cap(struct task_struct *p, int cpu, int prev_cpu)
+{
+ long min_cap, max_cap;
+
+ min_cap = min(capacity_orig_of(prev_cpu), capacity_orig_of(cpu));
+ max_cap = cpu_rq(cpu)->rd->max_cpu_capacity;
+
+ /* Minimum capacity is close to max, no need to abort wake_affine */
+ if (max_cap - min_cap < max_cap >> 3)
+ return 0;
+
+ return min_cap * 1024 < task_util(p) * capacity_margin;
+}
+
/*
* select_task_rq_fair: Select target runqueue for the waking task in domains
* that have the 'sd_flag' flag set. In practice, this is 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));
+ want_affine = !wake_wide(p) && !wake_cap(p, cpu, prev_cpu)
+ && cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
}
rcu_read_lock();
if (affine_sd) {
sd = NULL; /* Prefer wake_affine over balance flags */
- if (cpu != prev_cpu && wake_affine(affine_sd, p, sync))
+ if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync))
new_cpu = cpu;
}
if (!sd) {
if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
- new_cpu = select_idle_sibling(p, new_cpu);
+ new_cpu = select_idle_sibling(p, prev_cpu, new_cpu);
} else while (sd) {
struct sched_group *group;
*
* The adjacency matrix of the resulting graph is given by:
*
- * log_2 n
+ * log_2 n
* A_i,j = \Union (i % 2^k == 0) && i / 2^(k+1) == j / 2^(k+1) (6)
* k = 0
*
*
* [XXX write more on how we solve this.. _after_ merging pjt's patches that
* rewrite all of this once again.]
- */
+ */
static unsigned long __read_mostly max_load_balance_interval = HZ/10;
if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
int cpu;
- schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_affine);
env->flags |= LBF_SOME_PINNED;
env->flags &= ~LBF_ALL_PINNED;
if (task_running(env->src_rq, p)) {
- schedstat_inc(p, se.statistics.nr_failed_migrations_running);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_running);
return 0;
}
if (tsk_cache_hot <= 0 ||
env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
if (tsk_cache_hot == 1) {
- schedstat_inc(env->sd, lb_hot_gained[env->idle]);
- schedstat_inc(p, se.statistics.nr_forced_migrations);
+ schedstat_inc(env->sd->lb_hot_gained[env->idle]);
+ schedstat_inc(p->se.statistics.nr_forced_migrations);
}
return 1;
}
- schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+ schedstat_inc(p->se.statistics.nr_failed_migrations_hot);
return 0;
}
* so we can safely collect stats here rather than
* inside detach_tasks().
*/
- schedstat_inc(env->sd, lb_gained[env->idle]);
+ schedstat_inc(env->sd->lb_gained[env->idle]);
return p;
}
return NULL;
* so we can safely collect detach_one_task() stats here rather
* than inside detach_one_task().
*/
- schedstat_add(env->sd, lb_gained[env->idle], detached);
+ schedstat_add(env->sd->lb_gained[env->idle], detached);
return detached;
}
/*
* !SD_OVERLAP domains can assume that child groups
* span the current group.
- */
+ */
group = child->groups;
do {
load_above_capacity = busiest->sum_nr_running * SCHED_CAPACITY_SCALE;
if (load_above_capacity > busiest->group_capacity) {
load_above_capacity -= busiest->group_capacity;
- load_above_capacity *= NICE_0_LOAD;
+ load_above_capacity *= scale_load_down(NICE_0_LOAD);
load_above_capacity /= busiest->group_capacity;
} else
load_above_capacity = ~0UL;
cpumask_copy(cpus, cpu_active_mask);
- schedstat_inc(sd, lb_count[idle]);
+ schedstat_inc(sd->lb_count[idle]);
redo:
if (!should_we_balance(&env)) {
group = find_busiest_group(&env);
if (!group) {
- schedstat_inc(sd, lb_nobusyg[idle]);
+ schedstat_inc(sd->lb_nobusyg[idle]);
goto out_balanced;
}
busiest = find_busiest_queue(&env, group);
if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[idle]);
+ schedstat_inc(sd->lb_nobusyq[idle]);
goto out_balanced;
}
BUG_ON(busiest == env.dst_rq);
- schedstat_add(sd, lb_imbalance[idle], env.imbalance);
+ schedstat_add(sd->lb_imbalance[idle], env.imbalance);
env.src_cpu = busiest->cpu;
env.src_rq = busiest;
}
if (!ld_moved) {
- schedstat_inc(sd, lb_failed[idle]);
+ schedstat_inc(sd->lb_failed[idle]);
/*
* Increment the failure counter only on periodic balance.
* We do not want newidle balance, which can be very
* we can't migrate them. Let the imbalance flag set so parent level
* can try to migrate them.
*/
- schedstat_inc(sd, lb_balanced[idle]);
+ schedstat_inc(sd->lb_balanced[idle]);
sd->nr_balance_failed = 0;
}
static inline void
-update_next_balance(struct sched_domain *sd, int cpu_busy, unsigned long *next_balance)
+update_next_balance(struct sched_domain *sd, unsigned long *next_balance)
{
unsigned long interval, next;
- interval = get_sd_balance_interval(sd, cpu_busy);
+ /* used by idle balance, so cpu_busy = 0 */
+ interval = get_sd_balance_interval(sd, 0);
next = sd->last_balance + interval;
if (time_after(*next_balance, next))
rcu_read_lock();
sd = rcu_dereference_check_sched_domain(this_rq->sd);
if (sd)
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
rcu_read_unlock();
goto out;
continue;
if (this_rq->avg_idle < curr_cost + sd->max_newidle_lb_cost) {
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
break;
}
curr_cost += domain_cost;
}
- update_next_balance(sd, 0, &next_balance);
+ update_next_balance(sd, &next_balance);
/*
* Stop searching for tasks to pull if there are
.idle = CPU_IDLE,
};
- schedstat_inc(sd, alb_count);
+ schedstat_inc(sd->alb_count);
p = detach_one_task(&env);
if (p) {
- schedstat_inc(sd, alb_pushed);
+ schedstat_inc(sd->alb_pushed);
/* Active balancing done, reset the failure counter. */
sd->nr_balance_failed = 0;
} else {
- schedstat_inc(sd, alb_failed);
+ schedstat_inc(sd->alb_failed);
}
}
rcu_read_unlock();
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
if (!vruntime_normalized(p)) {
/*
}
/* Catch up with the cfs_rq and remove our load when we leave */
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
detach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
}
static void attach_task_cfs_rq(struct task_struct *p)
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
u64 now = cfs_rq_clock_task(cfs_rq);
- int tg_update;
#ifdef CONFIG_FAIR_GROUP_SCHED
/*
#endif
/* Synchronize task with its cfs_rq */
- tg_update = update_cfs_rq_load_avg(now, cfs_rq, false);
+ update_cfs_rq_load_avg(now, cfs_rq, false);
attach_entity_load_avg(cfs_rq, se);
- if (tg_update)
- update_tg_load_avg(cfs_rq, false);
+ update_tg_load_avg(cfs_rq, false);
if (!vruntime_normalized(p))
se->vruntime += cfs_rq->min_vruntime;
{
put_prev_task(rq, prev);
- schedstat_inc(rq, sched_goidle);
+ schedstat_inc(rq->sched_goidle);
return rq->idle;
}
*/
cpumask_var_t rto_mask;
struct cpupri cpupri;
+
+ unsigned long max_cpu_capacity;
};
extern struct root_domain def_root_domain;
#ifdef CONFIG_SMP
unsigned long last_load_update_tick;
#endif /* CONFIG_SMP */
- u64 nohz_stamp;
unsigned long nohz_flags;
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
if (rq)
rq->rq_sched_info.run_delay += delta;
}
-# define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
-# define schedstat_inc(rq, field) do { if (schedstat_enabled()) { (rq)->field++; } } while (0)
-# define schedstat_add(rq, field, amt) do { if (schedstat_enabled()) { (rq)->field += (amt); } } while (0)
-# define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
-# define schedstat_val(rq, field) ((schedstat_enabled()) ? (rq)->field : 0)
+#define schedstat_enabled() static_branch_unlikely(&sched_schedstats)
+#define schedstat_inc(var) do { if (schedstat_enabled()) { var++; } } while (0)
+#define schedstat_add(var, amt) do { if (schedstat_enabled()) { var += (amt); } } while (0)
+#define schedstat_set(var, val) do { if (schedstat_enabled()) { var = (val); } } while (0)
+#define schedstat_val(var) (var)
+#define schedstat_val_or_zero(var) ((schedstat_enabled()) ? (var) : 0)
#else /* !CONFIG_SCHEDSTATS */
static inline void
static inline void
rq_sched_info_depart(struct rq *rq, unsigned long long delta)
{}
-# define schedstat_enabled() 0
-# define schedstat_inc(rq, field) do { } while (0)
-# define schedstat_add(rq, field, amt) do { } while (0)
-# define schedstat_set(var, val) do { } while (0)
-# define schedstat_val(rq, field) 0
-#endif
+#define schedstat_enabled() 0
+#define schedstat_inc(var) do { } while (0)
+#define schedstat_add(var, amt) do { } while (0)
+#define schedstat_set(var, val) do { } while (0)
+#define schedstat_val(var) 0
+#define schedstat_val_or_zero(var) 0
+#endif /* CONFIG_SCHEDSTATS */
#ifdef CONFIG_SCHED_INFO
static inline void sched_info_reset_dequeued(struct task_struct *t)
if (kthread_should_park()) {
__set_current_state(TASK_RUNNING);
- preempt_enable();
if (ht->park && td->status == HP_THREAD_ACTIVE) {
BUG_ON(td->cpu != smp_processor_id());
ht->park(td->cpu);
td->status = HP_THREAD_PARKED;
}
+ preempt_enable();
kthread_parkme();
/* We might have been woken for stop */
continue;
cpu_stop_init_done(&done, 1);
if (!cpu_stop_queue_work(cpu, &work))
return -ENOENT;
+ /*
+ * In case @cpu == smp_proccessor_id() we can avoid a sleep+wakeup
+ * cycle by doing a preemption:
+ */
+ cond_resched();
wait_for_completion(&done.completion);
return done.ret;
}
}
/* See similar comment in do_numa_page for explanation */
- if (!(vma->vm_flags & VM_WRITE))
+ if (!pmd_write(pmd))
flags |= TNF_NO_GROUP;
/*
* pte_dirty has unpredictable behaviour between PTE scan updates,
* background writeback, dirty balancing and application behaviour.
*/
- if (!(vma->vm_flags & VM_WRITE))
+ if (!pte_write(pte))
flags |= TNF_NO_GROUP;
/*
"__stack_chk_fail",
"panic",
"do_exit",
+ "do_task_dead",
"__module_put_and_exit",
"complete_and_exit",
"kvm_spurious_fault",
projects / cascardo / linux.git / commitdiff