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| author | Peter Zijlstra <peterz@infradead.org> | 2024-10-04 14:46:58 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2024-11-05 12:55:38 +0100 |
| commit | 7c70cb94d29cd325fabe4a818c18613e3b9919a1 (patch) | |
| tree | 2c4d6b58f7e284778060e2aff70db2b87d7a977c /kernel/sched/fair.c | |
| parent | 26baa1f1c4bdc34b8d698c1900b407d863ad0e69 (diff) | |
| download | linux-next-7c70cb94d29cd325fabe4a818c18613e3b9919a1.tar.gz linux-next-7c70cb94d29cd325fabe4a818c18613e3b9919a1.zip | |
sched: Add Lazy preemption model
Change fair to use resched_curr_lazy(), which, when the lazy
preemption model is selected, will set TIF_NEED_RESCHED_LAZY.
This LAZY bit will be promoted to the full NEED_RESCHED bit on tick.
As such, the average delay between setting LAZY and actually
rescheduling will be TICK_NSEC/2.
In short, Lazy preemption will delay preemption for fair class but
will function as Full preemption for all the other classes, most
notably the realtime (RR/FIFO/DEADLINE) classes.
The goal is to bridge the performance gap with Voluntary, such that we
might eventually remove that option entirely.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org
Diffstat (limited to 'kernel/sched/fair.c')
| -rw-r--r-- | kernel/sched/fair.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6512258dc71f..3356315d7e64 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1251,7 +1251,7 @@ static void update_curr(struct cfs_rq *cfs_rq) return; if (resched || did_preempt_short(cfs_rq, curr)) { - resched_curr(rq); + resched_curr_lazy(rq); clear_buddies(cfs_rq, curr); } } @@ -5677,7 +5677,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued) * validating it and just reschedule. */ if (queued) { - resched_curr(rq_of(cfs_rq)); + resched_curr_lazy(rq_of(cfs_rq)); return; } #endif @@ -8829,7 +8829,7 @@ static void check_preempt_wakeup_fair(struct rq *rq, struct task_struct *p, int return; preempt: - resched_curr(rq); + resched_curr_lazy(rq); } static struct task_struct *pick_task_fair(struct rq *rq) |