Messages in this thread | | | Date | Thu, 14 Jul 2022 21:03:20 +0800 | Subject | Re: [External] Re: [PATCH v2 03/10] sched/fair: maintain task se depth in set_task_rq() | From | Chengming Zhou <> |
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On 2022/7/14 20:30, Dietmar Eggemann wrote: > On 13/07/2022 06:04, Chengming Zhou wrote: >> Previously we only maintain task se depth in task_move_group_fair(), >> if a !fair task change task group, its se depth will not be updated, >> so commit eb7a59b2c888 ("sched/fair: Reset se-depth when task switched to FAIR") >> fix the problem by updating se depth in switched_to_fair() too. > > Maybe it's worth mentioning how the se.depth setting from > task_move_group_fair() and switched_to_fair() went into > attach_task_cfs_rq() with commit daa59407b558 ("sched/fair: Unify > switched_{from,to}_fair() and task_move_group_fair()"} and further into > attach_entity_cfs_rq() with commit df217913e72e ("sched/fair: Factorize > attach/detach entity"). >
Good point, I will add this part in the next version.
Thanks for your review!
>> This patch move task se depth maintainence to set_task_rq(), which will be >> called when CPU/cgroup change, so its depth will always be correct. >> >> This patch is preparation for the next patch. >> >> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> > > Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> > >> --- >> kernel/sched/fair.c | 8 -------- >> kernel/sched/sched.h | 1 + >> 2 files changed, 1 insertion(+), 8 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 2a3e12ead144..bf595b622656 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -11539,14 +11539,6 @@ static void attach_entity_cfs_rq(struct sched_entity *se) >> { >> struct cfs_rq *cfs_rq = cfs_rq_of(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 >> - >> /* Synchronize entity with its cfs_rq */ >> update_load_avg(cfs_rq, se, sched_feat(ATTACH_AGE_LOAD) ? 0 : SKIP_AGE_LOAD); >> attach_entity_load_avg(cfs_rq, se); >> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h >> index aad7f5ee9666..8cc3eb7b86cd 100644 >> --- a/kernel/sched/sched.h >> +++ b/kernel/sched/sched.h >> @@ -1940,6 +1940,7 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) >> set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]); >> p->se.cfs_rq = tg->cfs_rq[cpu]; >> p->se.parent = tg->se[cpu]; >> + p->se.depth = tg->se[cpu] ? tg->se[cpu]->depth + 1 : 0; >> #endif >> >> #ifdef CONFIG_RT_GROUP_SCHED >
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