diff options
| author | Oleg Nesterov <oleg@redhat.com> | 2015-06-11 14:46:44 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-06-19 00:09:56 +0200 |
| commit | c04dca02bc73096435a5c36efd5ccb2171edcbe1 (patch) | |
| tree | 6875551d63882ac926b68a964c9629f45d0c4f7d | |
| parent | selftest: Timers: Avoid signal deadlock in leap-a-day (diff) | |
| download | linux-c04dca02bc73096435a5c36efd5ccb2171edcbe1.tar.xz linux-c04dca02bc73096435a5c36efd5ccb2171edcbe1.zip | |
hrtimer: Remove HRTIMER_STATE_MIGRATE
I do not understand HRTIMER_STATE_MIGRATE. Unless I am totally
confused it looks buggy and simply unneeded.
migrate_hrtimer_list() sets it to keep hrtimer_active() == T, but this
is not enough: this can fool, say, hrtimer_is_queued() in
dequeue_signal().
Can't migrate_hrtimer_list() simply use HRTIMER_STATE_ENQUEUED?
This fixes the race and we can kill STATE_MIGRATE.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124743.072387650@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | include/linux/hrtimer.h | 6 | ||||
| -rw-r--r-- | kernel/time/hrtimer.c | 7 |
2 files changed, 3 insertions, 10 deletions
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 3f82a7edc03d..2f9e57d3d126 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -70,17 +70,13 @@ enum hrtimer_restart { * the handling of the timer. * * The HRTIMER_STATE_ENQUEUED bit is always or'ed to the current state - * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. This - * also affects HRTIMER_STATE_MIGRATE where the preservation is not - * necessary. HRTIMER_STATE_MIGRATE is cleared after the timer is - * enqueued on the new cpu. + * to preserve the HRTIMER_STATE_CALLBACK in the above scenario. * * All state transitions are protected by cpu_base->lock. */ #define HRTIMER_STATE_INACTIVE 0x00 #define HRTIMER_STATE_ENQUEUED 0x01 #define HRTIMER_STATE_CALLBACK 0x02 -#define HRTIMER_STATE_MIGRATE 0x04 /** * struct hrtimer - the basic hrtimer structure diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 278d4b36fd94..b1b795e5e0b1 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -1508,11 +1508,11 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, debug_deactivate(timer); /* - * Mark it as STATE_MIGRATE not INACTIVE otherwise the + * Mark it as ENQUEUED not INACTIVE otherwise the * timer could be seen as !active and just vanish away * under us on another CPU */ - __remove_hrtimer(timer, old_base, HRTIMER_STATE_MIGRATE, 0); + __remove_hrtimer(timer, old_base, HRTIMER_STATE_ENQUEUED, 0); timer->base = new_base; /* * Enqueue the timers on the new cpu. This does not @@ -1523,9 +1523,6 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base, * event device. */ enqueue_hrtimer(timer, new_base); - - /* Clear the migration state bit */ - timer->state &= ~HRTIMER_STATE_MIGRATE; } } |