6.12-stable review patch. If anyone has any objections, please let me know.
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From: Xuewen Yan xuewen.yan@unisoc.com
[ 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: 152e11f6df29 ("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 --- kernel/sched/fair.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 47ff4856561ea..7280ed04c96ce 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -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;