Subject: sched: Move blk_schedule_flush_plug() out of __schedule() From: Thomas Gleixner Date: Wed, 22 Jun 2011 19:47:01 +0200 There is no real reason to run blk_schedule_flush_plug() with interrupts and preemption disabled. Move it into schedule() and call it when the task is going voluntarily to sleep. There might be false positives when the task is woken between that call and actually scheduling, but that's not really different from being woken immediately after switching away. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Tejun Heo Cc: Jens Axboe Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20110622174918.917236198@linutronix.de Signed-off-by: Thomas Gleixner --- kernel/sched.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -4253,16 +4253,6 @@ need_resched: if (to_wakeup) try_to_wake_up_local(to_wakeup); } - - /* - * If we are going to sleep and we have plugged IO - * queued, make sure to submit it to avoid deadlocks. - */ - if (blk_needs_flush_plug(prev)) { - raw_spin_unlock(&rq->lock); - blk_schedule_flush_plug(prev); - raw_spin_lock(&rq->lock); - } } switch_count = &prev->nvcsw; } @@ -4301,8 +4291,23 @@ need_resched: goto need_resched; } +static inline void sched_submit_work(struct task_struct *tsk) +{ + if (!tsk->state) + return; + /* + * If we are going to sleep and we have plugged IO queued, + * make sure to submit it to avoid deadlocks. + */ + if (blk_needs_flush_plug(tsk)) + blk_schedule_flush_plug(tsk); +} + asmlinkage void schedule(void) { + struct task_struct *tsk = current; + + sched_submit_work(tsk); __schedule(); } EXPORT_SYMBOL(schedule);