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| author | Byungchul Park <byungchul.park@lge.com> | 2015-08-10 18:02:55 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-08-12 12:06:09 +0200 |
| commit | 7855a35ac07a350e2cd26f09568a6d8e372be358 (patch) | |
| tree | abb27dda433ad9c731f82ac5c4901c0b44457548 /kernel/sched | |
| parent | e237882b8f83dd1a0eece1608bcb689d4f4b221b (diff) | |
| download | linux-7855a35ac07a350e2cd26f09568a6d8e372be358.tar.gz linux-7855a35ac07a350e2cd26f09568a6d8e372be358.tar.bz2 linux-7855a35ac07a350e2cd26f09568a6d8e372be358.zip | |
sched: Ensure a task has a non-normalized vruntime when returning back to CFS
Current code ensures that a task has a normalized vruntime when switching away
from the fair class, but it does not ensure the task has a non-normalized
vruntime when switching back to the fair class.
This is an example breaking this consistency:
1. a task is in fair class and !queued
2. changes its class to RT class (still !queued)
3. changes its class to fair class again (still !queued)
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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>
Link: http://lkml.kernel.org/r/1439197375-27927-1-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/fair.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 858b94ab1bd2..f0950fde1f5b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7930,16 +7930,31 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p) */ static void switched_to_fair(struct rq *rq, struct task_struct *p) { -#ifdef CONFIG_FAIR_GROUP_SCHED struct sched_entity *se = &p->se; + +#ifdef CONFIG_FAIR_GROUP_SCHED /* * Since the real-depth could have been changed (only FAIR * class maintain depth value), reset depth properly. */ se->depth = se->parent ? se->parent->depth + 1 : 0; #endif - if (!task_on_rq_queued(p)) + + if (!task_on_rq_queued(p)) { + + /* + * Ensure the task has a non-normalized vruntime when it is switched + * back to the fair class with !queued, so that enqueue_entity() at + * wake-up time will do the right thing. + * + * If it's queued, then the enqueue_entity(.flags=0) makes the task + * has non-normalized vruntime, if it's !queued, then it still has + * normalized vruntime. + */ + if (p->state != TASK_RUNNING) + se->vruntime += cfs_rq_of(se)->min_vruntime; return; + } /* * We were most likely switched from sched_rt, so |