[PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP

From: chengming . zhou
Date: Wed Sep 13 2023 - 09:20:52 EST


From: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>

We don't need to maintain per-queue leaf_cfs_rq_list on !SMP, since
it's used for cfs_rq load tracking & balance on SMP.

But sched debug interface use it to print per-cfs_rq stats, which
maybe better to change to use walk_tg_tree_from() instead.

This patch just fix the !SMP version cfs_rq_is_decayed(), so the
per-queue leaf_cfs_rq_list is also maintained correctly on !SMP,
to fix the warning in assert_list_leaf_cfs_rq().

Fixes: 0a00a354644e ("sched/fair: Delete useless condition in tg_unthrottle_up()")
Reported-by: Leo Yu-Chi Liang <ycliang@xxxxxxxxxxxxx>
Closes: https://lore.kernel.org/all/ZN87UsqkWcFLDxea@swlinux02/
Tested-by: Leo Yu-Chi Liang <ycliang@xxxxxxxxxxxxx>
Reviewed-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8dbff6e7ad4f..845d7729320e 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4878,7 +4878,7 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq)

static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
{
- return true;
+ return !(cfs_rq->nr_running);
}

#define UPDATE_TG 0x0
--
2.40.1