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-rw-r--r--kernel/sched.c71
1 files changed, 62 insertions, 9 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index d1ad69b..8dcdec6 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -594,18 +594,14 @@ enum {
SCHED_FEAT_NEW_FAIR_SLEEPERS = 1,
SCHED_FEAT_WAKEUP_PREEMPT = 2,
SCHED_FEAT_START_DEBIT = 4,
- SCHED_FEAT_TREE_AVG = 8,
- SCHED_FEAT_APPROX_AVG = 16,
- SCHED_FEAT_HRTICK = 32,
- SCHED_FEAT_DOUBLE_TICK = 64,
+ SCHED_FEAT_HRTICK = 8,
+ SCHED_FEAT_DOUBLE_TICK = 16,
};
const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 |
SCHED_FEAT_WAKEUP_PREEMPT * 1 |
SCHED_FEAT_START_DEBIT * 1 |
- SCHED_FEAT_TREE_AVG * 0 |
- SCHED_FEAT_APPROX_AVG * 0 |
SCHED_FEAT_HRTICK * 1 |
SCHED_FEAT_DOUBLE_TICK * 0;
@@ -1056,6 +1052,49 @@ static void resched_cpu(int cpu)
resched_task(cpu_curr(cpu));
spin_unlock_irqrestore(&rq->lock, flags);
}
+
+#ifdef CONFIG_NO_HZ
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+void wake_up_idle_cpu(int cpu)
+{
+ struct rq *rq = cpu_rq(cpu);
+
+ if (cpu == smp_processor_id())
+ return;
+
+ /*
+ * This is safe, as this function is called with the timer
+ * wheel base lock of (cpu) held. When the CPU is on the way
+ * to idle and has not yet set rq->curr to idle then it will
+ * be serialized on the timer wheel base lock and take the new
+ * timer into account automatically.
+ */
+ if (rq->curr != rq->idle)
+ return;
+
+ /*
+ * We can set TIF_RESCHED on the idle task of the other CPU
+ * lockless. The worst case is that the other CPU runs the
+ * idle task through an additional NOOP schedule()
+ */
+ set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
+
+ /* NEED_RESCHED must be visible before we test polling */
+ smp_mb();
+ if (!tsk_is_polling(rq->idle))
+ smp_send_reschedule(cpu);
+}
+#endif
+
#else
static void __resched_task(struct task_struct *p, int tif_bit)
{
@@ -1396,6 +1435,12 @@ task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
{
s64 delta;
+ /*
+ * Buddy candidates are cache hot:
+ */
+ if (&p->se == cfs_rq_of(&p->se)->next)
+ return 1;
+
if (p->sched_class != &fair_sched_class)
return 0;
@@ -1855,10 +1900,11 @@ out_activate:
schedstat_inc(p, se.nr_wakeups_remote);
update_rq_clock(rq);
activate_task(rq, p, 1);
- check_preempt_curr(rq, p);
success = 1;
out_running:
+ check_preempt_curr(rq, p);
+
p->state = TASK_RUNNING;
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
@@ -1892,6 +1938,8 @@ static void __sched_fork(struct task_struct *p)
p->se.exec_start = 0;
p->se.sum_exec_runtime = 0;
p->se.prev_sum_exec_runtime = 0;
+ p->se.last_wakeup = 0;
+ p->se.avg_overlap = 0;
#ifdef CONFIG_SCHEDSTATS
p->se.wait_start = 0;
@@ -3877,7 +3925,7 @@ need_resched_nonpreemptible:
if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
- unlikely(signal_pending(prev)))) {
+ signal_pending(prev))) {
prev->state = TASK_RUNNING;
} else {
deactivate_task(rq, prev, 1);
@@ -6802,6 +6850,10 @@ static int ndoms_cur; /* number of sched domains in 'doms_cur' */
*/
static cpumask_t fallback_doms;
+void __attribute__((weak)) arch_update_cpu_topology(void)
+{
+}
+
/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
* For now this just excludes isolated cpus, but could be used to
@@ -6811,6 +6863,7 @@ static int arch_init_sched_domains(const cpumask_t *cpu_map)
{
int err;
+ arch_update_cpu_topology();
ndoms_cur = 1;
doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
if (!doms_cur)
@@ -6915,7 +6968,7 @@ match2:
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
-static int arch_reinit_sched_domains(void)
+int arch_reinit_sched_domains(void)
{
int err;
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