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>
This commit is contained in:
Richard Cochran 2016-07-13 17:16:59 +00:00 committed by Ingo Molnar
parent 27590dc17b
commit 24f73b9971
4 changed files with 14 additions and 23 deletions

View file

@ -1195,6 +1195,11 @@ static struct cpuhp_step cpuhp_bp_states[] = {
.startup = hrtimers_prepare_cpu,
.teardown = hrtimers_dead_cpu,
},
[CPUHP_TIMERS_DEAD] = {
.name = "timers dead",
.startup = NULL,
.teardown = timers_dead_cpu,
},
/*
* Preparatory and dead notifiers. Will be replaced once the notifiers
* are converted to states.