Messages in this thread | | | Date | Mon, 8 Apr 2024 11:16:05 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 5/5] sched/fair: Rename set_next_buddy() to set_next_pick() |
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On Sun, Apr 07, 2024 at 10:43:19AM +0200, Ingo Molnar wrote: > This is a mechanism to set the next task_pick target, > 'buddy' is too ambiguous and refers to a historic feature we > don't have anymore. > > Signed-off-by: Ingo Molnar <mingo@kernel.org> > --- > kernel/sched/fair.c | 28 +++++++++++++--------------- > 1 file changed, 13 insertions(+), 15 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 93ea653065f5..fe730f232ffd 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -3200,7 +3200,16 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) > hrtick_update(rq); > } > > -static void set_next_buddy(struct sched_entity *se); > +static void set_next_pick(struct sched_entity *se) > +{ > + for_each_sched_entity(se) { > + if (SCHED_WARN_ON(!se->on_rq)) > + return; > + if (se_is_idle(se)) > + return; > + cfs_rq_of(se)->next = se; > + } > +} > > /* > * The dequeue_task method is called before nr_running is > @@ -3240,7 +3249,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) > * p is sleeping when it is within its sched_slice. > */ > if (task_sleep && se && !throttled_hierarchy(cfs_rq)) > - set_next_buddy(se); > + set_next_pick(se); > break; > } > flags |= DEQUEUE_SLEEP; > @@ -4631,17 +4640,6 @@ balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) > static inline void set_task_max_allowed_capacity(struct task_struct *p) {} > #endif /* CONFIG_SMP */ > > -static void set_next_buddy(struct sched_entity *se) > -{ > - for_each_sched_entity(se) { > - if (SCHED_WARN_ON(!se->on_rq)) > - return; > - if (se_is_idle(se)) > - return; > - cfs_rq_of(se)->next = se; > - } > -} > -
Hurmmm.. afaict the only actual user of cfs_rq->next left is task_hot(), no? Is that thing worth it?
That is, should we not totally nuke the thing?
> /* > * Preempt the current task with a newly woken task if needed: > */ > @@ -4769,7 +4767,7 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf > goto simple; > > /* > - * Because of the set_next_buddy() in dequeue_task_fair() it is rather > + * Because of the set_next_pick() in dequeue_task_fair() it is rather > * likely that a next task is from the same cgroup as the current. > *
So, given you killed the ->next consideration in pick, isn't this comment 'misleading' at best?
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