sched/eevdf: Force propagating min_slice of cfs_rq when {en,de}queue tasks

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

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 17847527aa20225cb9c6544b43ea06997ada2b13..9279bfb740406a5d93aa75719605c667512713d6 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7002,6 +7002,8 @@ 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;
@@ -7131,6 +7133,8 @@ 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;