From afae8002b4fd3560c8f5f1567f3c3202c30a70fa Mon Sep 17 00:00:00 2001 From: Tianchen Ding Date: Wed, 6 Mar 2024 10:21:33 +0800 Subject: sched/eevdf: Fix miscalculation in reweight_entity() when se is not curr reweight_eevdf() only keeps V unchanged inside itself. When se != cfs_rq->curr, it would be dequeued from rb tree first. So that V is changed and the result is wrong. Pass the original V to reweight_eevdf() to fix this issue. Fixes: eab03c23c2a1 ("sched/eevdf: Fix vruntime adjustment on reweight") Signed-off-by: Tianchen Ding [peterz: flip if() condition for clarity] Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Abel Wu Link: https://lkml.kernel.org/r/20240306022133.81008-3-dtcccc@linux.alibaba.com --- kernel/sched/fair.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 5551ce2af73e7e..6d266917d38d7f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -3676,11 +3676,10 @@ static inline void dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { } #endif -static void reweight_eevdf(struct cfs_rq *cfs_rq, struct sched_entity *se, +static void reweight_eevdf(struct sched_entity *se, u64 avruntime, unsigned long weight) { unsigned long old_weight = se->load.weight; - u64 avruntime = avg_vruntime(cfs_rq); s64 vlag, vslice; /* @@ -3787,24 +3786,26 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, unsigned long weight) { bool curr = cfs_rq->curr == se; + u64 avruntime; if (se->on_rq) { /* commit outstanding execution time */ update_curr(cfs_rq); + avruntime = avg_vruntime(cfs_rq); if (!curr) __dequeue_entity(cfs_rq, se); update_load_sub(&cfs_rq->load, se->load.weight); } dequeue_load_avg(cfs_rq, se); - if (!se->on_rq) { + if (se->on_rq) { + reweight_eevdf(se, avruntime, weight); + } else { /* * Because we keep se->vlag = V - v_i, while: lag_i = w_i*(V - v_i), * we need to scale se->vlag when w_i changes. */ se->vlag = div_s64(se->vlag * se->load.weight, weight); - } else { - reweight_eevdf(cfs_rq, se, weight); } update_load_set(&se->load, weight); -- cgit 1.2.3-korg