6.12-stable review patch. If anyone has any objections, please let me know.
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From: Tianchen Ding dtcccc@linux.alibaba.com
[ Upstream commit 563bc2161b94571ea425bbe2cf69fd38e24cdedf ]
When a task is enqueued and its parent cgroup se is already on_rq, this parent cgroup se will not be enqueued again, and hence the root->min_slice leaves unchanged. The same issue happens when a task is dequeued and its parent cgroup se has other runnable entities, and the parent cgroup se will not be dequeued.
Force propagating min_slice when se doesn't need to be enqueued or dequeued. Ensure the se hierarchy always get the latest min_slice.
Fixes: aef6987d8954 ("sched/eevdf: Propagate min_slice up the cgroup hierarchy") Signed-off-by: Tianchen Ding dtcccc@linux.alibaba.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://lkml.kernel.org/r/20250211063659.7180-1-dtcccc@linux.alibaba.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 49e340f9fa71b..ceb023629d48d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7103,6 +7103,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) update_cfs_group(se);
se->slice = slice; + if (se != cfs_rq->curr) + min_vruntime_cb_propagate(&se->run_node, NULL); slice = cfs_rq_min_slice(cfs_rq);
cfs_rq->h_nr_running++; @@ -7232,6 +7234,8 @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags) update_cfs_group(se);
se->slice = slice; + if (se != cfs_rq->curr) + min_vruntime_cb_propagate(&se->run_node, NULL); slice = cfs_rq_min_slice(cfs_rq);
cfs_rq->h_nr_running -= h_nr_running;