| From | Daniel Jordan <> | Subject | [PATCH] sched/fair: Always update_curr() before placing at enqueue | Date | Fri, 6 Oct 2023 12:48:26 -0400 |
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Placing wants current's vruntime and the cfs_rq's min_vruntime up to date so that avg_runtime() is too, and similarly it wants the entity to be re-weighted and lag adjusted so vslice and vlag are fresh, so always do update_curr() and update_cfs_group() beforehand.
There doesn't seem to be a reason to treat the 'curr' case specially after e8f331bcc270 since vruntime doesn't get normalized anymore.
Fixes: e8f331bcc270 ("sched/smp: Use lag to simplify cross-runqueue placement") Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> ---
Not sure what the XXX above place_entity() is for, maybe it can go away?
Based on tip/sched/core.
kernel/sched/fair.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 04fbcbda97d5f..db2ca9bf9cc49 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5047,15 +5047,6 @@ static inline bool cfs_bandwidth_used(void); static void enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) { - bool curr = cfs_rq->curr == se; - - /* - * If we're the current task, we must renormalise before calling - * update_curr(). - */ - if (curr) - place_entity(cfs_rq, se, flags); - update_curr(cfs_rq); /* @@ -5080,8 +5071,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) * XXX now that the entity has been re-weighted, and it's lag adjusted, * we can place the entity. */ - if (!curr) - place_entity(cfs_rq, se, flags); + place_entity(cfs_rq, se, flags); account_entity_enqueue(cfs_rq, se); @@ -5091,7 +5081,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) check_schedstat_required(); update_stats_enqueue_fair(cfs_rq, se, flags); - if (!curr) + if (cfs_rq->curr != se) __enqueue_entity(cfs_rq, se); se->on_rq = 1; -- 2.41.0
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