sched: Add a check for cpu unbound deferrable timers
Add a check for cpu unbound deferrable timer expiry and raise
softirq for handling the expired timers so that the CPU can
process the cpu unbound deferrable times as early as possible
when a cpu tries to enter/exit idle loop.
Change-Id: Ieffa74fa22a4d25493f5590b5ac1e0d784fcbbad
Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index adede73..3a2dd86 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -207,6 +207,7 @@
static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]);
struct timer_base timer_base_deferrable;
+static atomic_t deferrable_pending;
#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON)
unsigned int sysctl_timer_migration = 1;
@@ -1460,6 +1461,31 @@
return DIV_ROUND_UP_ULL(nextevt, TICK_NSEC) * TICK_NSEC;
}
+
+#ifdef CONFIG_SMP
+/*
+ * check_pending_deferrable_timers - Check for unbound deferrable timer expiry
+ * @cpu - Current CPU
+ *
+ * The function checks whether any global deferrable pending timers
+ * are exipired or not. This function does not check cpu bounded
+ * diferrable pending timers expiry.
+ *
+ * The function returns true when a cpu unbounded deferrable timer is expired.
+ */
+bool check_pending_deferrable_timers(int cpu)
+{
+ if (cpu == tick_do_timer_cpu ||
+ tick_do_timer_cpu == TICK_DO_TIMER_NONE) {
+ if (time_after_eq(jiffies, timer_base_deferrable.clk)
+ && !atomic_cmpxchg(&deferrable_pending, 0, 1)) {
+ return true;
+ }
+ }
+ return false;
+}
+#endif
+
/**
* get_next_timer_interrupt - return the time (clock mono) of the next timer
* @basej: base time jiffies
@@ -1619,10 +1645,13 @@
struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_STD]);
__run_timers(base);
- if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active) {
- __run_timers(&timer_base_deferrable);
+ if (IS_ENABLED(CONFIG_NO_HZ_COMMON) && base->nohz_active)
__run_timers(this_cpu_ptr(&timer_bases[BASE_DEF]));
- }
+
+ if ((atomic_cmpxchg(&deferrable_pending, 1, 0) &&
+ tick_do_timer_cpu == TICK_DO_TIMER_NONE) ||
+ tick_do_timer_cpu == smp_processor_id())
+ __run_timers(&timer_base_deferrable);
}
/*