diff options
| author | K Prateek Nayak <kprateek.nayak@amd.com> | 2024-11-28 12:59:54 +0530 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-12-09 11:48:09 +0100 |
| commit | 493afbd187c4c9cc1642792c0d9ba400c3d6d90d (patch) | |
| tree | a2be3bced207e135f615b482af71aec9a2a2f239 /kernel | |
| parent | 82f9cc094975240885c93effbca7f4603f5de1bf (diff) | |
sched/fair: Fix NEXT_BUDDY
Adam reports that enabling NEXT_BUDDY insta triggers a WARN in
pick_next_entity().
Moving clear_buddies() up before the delayed dequeue bits ensures
no ->next buddy becomes delayed. Further ensure no new ->next buddy
ever starts as delayed.
Fixes: 152e11f6df29 ("sched/fair: Implement delayed dequeue")
Reported-by: Adam Li <adamli@os.amperecomputing.com>
Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Adam Li <adamli@os.amperecomputing.com>
Link: https://lkml.kernel.org/r/670a0d54-e398-4b1f-8a6e-90784e2fdf89@amd.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 05b8f1eb2c14..9d7a2dd2c260 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5478,6 +5478,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) bool sleep = flags & DEQUEUE_SLEEP; update_curr(cfs_rq); + clear_buddies(cfs_rq, se); if (flags & DEQUEUE_DELAYED) { SCHED_WARN_ON(!se->sched_delayed); @@ -5494,8 +5495,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) if (sched_feat(DELAY_DEQUEUE) && delay && !entity_eligible(cfs_rq, se)) { - if (cfs_rq->next == se) - cfs_rq->next = NULL; update_load_avg(cfs_rq, se, 0); se->sched_delayed = 1; return false; @@ -5520,8 +5519,6 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) update_stats_dequeue_fair(cfs_rq, se, flags); - clear_buddies(cfs_rq, se); - update_entity_lag(cfs_rq, se); if (sched_feat(PLACE_REL_DEADLINE) && !sleep) { se->deadline -= se->vruntime; @@ -8774,7 +8771,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int if (unlikely(throttled_hierarchy(cfs_rq_of(pse)))) return; - if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK)) { + if (sched_feat(NEXT_BUDDY) && !(wake_flags & WF_FORK) && !pse->sched_delayed) { set_next_buddy(pse); } |