Commit-ID: c04dca02bc73096435a5c36efd5ccb2171edcbe1 Gitweb: http://git.kernel.org/tip/c04dca02bc73096435a5c36efd5ccb2171edcbe1 Author: Oleg Nesterov <o...@redhat.com> AuthorDate: Thu, 11 Jun 2015 14:46:44 +0200 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Fri, 19 Jun 2015 00:09:56 +0200
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 <o...@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: ktk...@parallels.com Cc: rost...@goodmis.org Cc: juri.le...@gmail.com Cc: pang.xun...@linaro.org Cc: wanpeng...@linux.intel.com Cc: umgwanakikb...@gmail.com Link: http://lkml.kernel.org/r/20150611124743.072387...@infradead.org Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- include/linux/hrtimer.h | 6 +----- 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 3f82a7e..2f9e57d 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 278d4b3..b1b795e 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; } } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
