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authorRichard Cochran <rcochran@linutronix.de>2016-07-13 17:16:59 +0000
committerIngo Molnar <mingo@kernel.org>2016-07-15 10:41:42 +0200
commit24f73b99716a9cd8cbb345c41ced6b3b5ed94006 (patch)
tree382df7b88299425d8f3af5b050b7ba26273ea0c5 /kernel/time
parent27590dc17b34aedc4f3e14bd107ee59b9db9b0a6 (diff)
downloadlinux-24f73b99716a9cd8cbb345c41ced6b3b5ed94006.tar.bz2
timers/core: Convert to hotplug state machine
When tearing down, call timers_dead_cpu() before notify_dead(). There is a hidden dependency between: - timers - block multiqueue - rcutree If timers_dead_cpu() comes later than blk_mq_queue_reinit_notify() that latter function causes a RCU stall. Signed-off-by: Richard Cochran <rcochran@linutronix.de> Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: John Stultz <john.stultz@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: rt@linutronix.de Link: http://lkml.kernel.org/r/20160713153337.566790058@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/timer.c25
1 files changed, 2 insertions, 23 deletions
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index cb9ab401e2d9..555670a5143c 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1804,7 +1804,7 @@ static void migrate_timer_list(struct timer_base *new_base, struct hlist_head *h
}
}
-static void migrate_timers(int cpu)
+int timers_dead_cpu(unsigned int cpu)
{
struct timer_base *old_base;
struct timer_base *new_base;
@@ -1831,29 +1831,9 @@ static void migrate_timers(int cpu)
spin_unlock_irq(&new_base->lock);
put_cpu_ptr(&timer_bases);
}
+ return 0;
}
-static int timer_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- switch (action) {
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- migrate_timers((long)hcpu);
- break;
- default:
- break;
- }
-
- return NOTIFY_OK;
-}
-
-static inline void timer_register_cpu_notifier(void)
-{
- cpu_notifier(timer_cpu_notify, 0);
-}
-#else
-static inline void timer_register_cpu_notifier(void) { }
#endif /* CONFIG_HOTPLUG_CPU */
static void __init init_timer_cpu(int cpu)
@@ -1881,7 +1861,6 @@ void __init init_timers(void)
{
init_timer_cpus();
init_timer_stats();
- timer_register_cpu_notifier();
open_softirq(TIMER_SOFTIRQ, run_timer_softirq);
}