Messages in this thread Patch in this message |  | | From | Tianchen Ding <> | | Subject | [PATCH v3] sched/eevdf: Force propagating min_slice of cfs_rq when {en,de}queue tasks | | Date | Tue, 11 Feb 2025 14:36:59 +0800 |
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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> --- v3: I modified some descriptions in commit log, and rebased to the latest tip branch. The old version of patch can be found in [1].
The original patchset wants to add a feature. As the 2nd patch may be hard to be accepted, I think at least the bugfix should be applied.
The issue about this patch was described detailly in [2].
[1]https://lore.kernel.org/all/20241031094822.30531-1-dtcccc@linux.alibaba.com/ [2]https://lore.kernel.org/all/a903d0dc-1d88-4ae7-ac81-3eed0445654d@linux.alibaba.com/ --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1e78caa21436..0d479b92633a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6970,6 +6970,8 @@ 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_runnable += h_nr_runnable; @@ -7099,6 +7101,8 @@ 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_runnable -= h_nr_runnable; -- 2.39.3
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