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sched/fair: Fixup wake_up_sync() vs DELAYED_DEQUEUE

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[ Upstream commit aa3ee4f0b7541382c9f6f43f7408d73a5d4f4042 ]

Delayed dequeued feature keeps a sleeping task enqueued until its
lag has elapsed. As a result, it stays also visible in rq->nr_running.
So when in wake_affine_idle(), we should use the real running-tasks
in rq to check whether we should place the wake-up task to
current cpu.
On the other hand, add a helper function to return the nr-delayed.

Fixes: 152e11f6df ("sched/fair: Implement delayed dequeue")
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Reviewed-and-tested-by: Tianchen Ding <dtcccc@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20250303105241.17251-2-xuewen.yan@unisoc.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xuewen Yan
2025-03-03 18:52:39 +08:00
committed by Greg Kroah-Hartman
parent 3edcabcfc2
commit a2562bdd35
1 changed files with 11 additions and 2 deletions
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13
kernel/sched/fair.c
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@@ -7313,6 +7313,11 @@ static bool dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
return true;
}
static inline unsigned int cfs_h_nr_delayed(struct rq *rq)
{
return (rq->cfs.h_nr_queued - rq->cfs.h_nr_runnable);
}
#ifdef CONFIG_SMP
/* Working cpumask for: sched_balance_rq(), sched_balance_newidle(). */
@@ -7474,8 +7479,12 @@ wake_affine_idle(int this_cpu, int prev_cpu, int sync)
if (available_idle_cpu(this_cpu) && cpus_share_cache(this_cpu, prev_cpu))
return available_idle_cpu(prev_cpu) ? prev_cpu : this_cpu;
if (sync && cpu_rq(this_cpu)->nr_running == 1)
return this_cpu;
if (sync) {
struct rq *rq = cpu_rq(this_cpu);
if ((rq->nr_running - cfs_h_nr_delayed(rq)) == 1)
return this_cpu;
}
if (available_idle_cpu(prev_cpu))
return prev_cpu;