sched/fair: Fix the min_vruntime update logic in dequeue_entity()
authorSong Muchun <smuchun@gmail.com>
Sun, 14 Oct 2018 11:26:12 +0000 (19:26 +0800)
committerIngo Molnar <mingo@kernel.org>
Tue, 16 Oct 2018 07:36:01 +0000 (09:36 +0200)
The comment and the code around the update_min_vruntime() call in
dequeue_entity() are not in agreement.

From commit:

  b60205c7c558 ("sched/fair: Fix min_vruntime tracking")

I think that we want to update min_vruntime when a task is sleeping/migrating.
So, the check is inverted there - fix it.

Signed-off-by: Song Muchun <smuchun@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: b60205c7c558 ("sched/fair: Fix min_vruntime tracking")
Link: http://lkml.kernel.org/r/20181014112612.2614-1-smuchun@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
kernel/sched/fair.c

index f88e007..908c9cd 100644 (file)
@@ -4001,7 +4001,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
         * put back on, and if we advance min_vruntime, we'll be placed back
         * further than we started -- ie. we'll be penalized.
         */
-       if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
+       if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE)
                update_min_vruntime(cfs_rq);
 }