evie/android_kernel_oneplus_msm8998
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timer: Ensure timers are not running before migrating

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This is needed to support migration of timers during cpu isolation. A
timer might be running on the CPU that we want to isolate so we are
unable to migrate the timers at this point. We are adding a spin-loop to
wait for the timer to finish before migrating the timers.

Change-Id: I24d6e91b6dff468c640c2fe3a37a7f31b6f0c79a
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
This commit is contained in:
Olav Haugan 2016-07-08 10:59:08 -07:00
parent 9e2d528dc4
commit 6cc98f03ad
1 changed files with 14 additions and 3 deletions
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17
kernel/time/timer.c
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@ -1635,7 +1635,7 @@ static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *he
}
}
static void migrate_timers(int cpu)
static void migrate_timers(int cpu, bool wait)
{
struct tvec_base *old_base;
struct tvec_base *new_base;
@ -1651,7 +1651,18 @@ static void migrate_timers(int cpu)
spin_lock_irq(&new_base->lock);
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
BUG_ON(old_base->running_timer);
if (wait) {
/* Ensure timers are done running before continuing */
while (old_base->running_timer) {
spin_unlock(&old_base->lock);
spin_unlock_irq(&new_base->lock);
cpu_relax();
spin_lock_irq(&new_base->lock);
spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
}
} else {
BUG_ON(old_base->running_timer);
}
for (i = 0; i < TVR_SIZE; i++)
migrate_timer_list(new_base, old_base->tv1.vec + i);
@ -1676,7 +1687,7 @@ static int timer_cpu_notify(struct notifier_block *self,
switch (action) {
case CPU_DEAD:
case CPU_DEAD_FROZEN:
migrate_timers((long)hcpu);
migrate_timers((long)hcpu, false);
break;
default:
break;