[PATCH] sched/eevdf: Update se->vprot in reweight_entity()

[Wang Tao <wangtao554@huawei.com>]

In the EEVDF framework with Run-to-Parity protection, `se->vprot` is an
independent variable defining the virtual protection timestamp.

When `reweight_entity()` is called (e.g., via nice/renice), it performs
the following actions to preserve Lag consistency:
1. Scales `se->vlag` based on the new weight.
2. Calls `place_entity()`, which recalculates `se->vruntime` based on
   the new weight and scaled lag.

However, the current implementation fails to update `se->vprot`, leading
to mismatches between the task's actual runtime and its expected duration.

This patch fixes the issue by calling `set_protect_slice()` at the end of
`reweight_entity()`. This ensures that a new, valid protection slice is
committed based on the updated `vruntime` and the new weight, restoring
Run-to-Parity consistency immediately after a weight change.

Fixes: 63304558ba5d ("sched/eevdf: Curb wakeup-preemption")
Suggested-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Wang Tao <wangtao554@huawei.com>
---
 kernel/sched/fair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e71302282671..bdd8c4e688ae 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3792,6 +3792,8 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
 		if (!curr)
 			__enqueue_entity(cfs_rq, se);
 		cfs_rq->nr_queued++;
+		if (curr)
+			set_protect_slice(cfs_rq, se);
 	}
 }
 
-- 
2.34.1