When a task changes slice and its cgroup se is already on_rq, the cgroup se will not be enqueued again, and hence the root->min_slice leaves unchanged. Force propagating it 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> --- kernel/sched/fair.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index XXXXXXX..XXXXXXX 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -XXX,XX +XXX,XX @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) update_cfs_group(se); se->slice = slice; + min_vruntime_cb_propagate(&se->run_node, NULL); slice = cfs_rq_min_slice(cfs_rq); cfs_rq->h_nr_running++; @@ -XXX,XX +XXX,XX @@ static int dequeue_entities(struct rq *rq, struct sched_entity *se, int flags) update_cfs_group(se); se->slice = slice; + min_vruntime_cb_propagate(&se->run_node, NULL); slice = cfs_rq_min_slice(cfs_rq); cfs_rq->h_nr_running -= h_nr_running; -- 2.39.3 When a task changes slice and its cgroup se is already on_rq, the cgroup se will not be enqueued again, and hence the root->min_slice leaves unchanged. Force propagating it 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> --- v2: Add a check about effectiveness of se->run_node. Thanks to the kernel test robot. --- kernel/sched/fair.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index XXXXXXX..XXXXXXX 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -XXX,XX +XXX,XX @@ 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++; @@ -XXX,XX +XXX,XX @@ 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; -- 2.39.3