2023-09-13 20:15:49

by Chengming Zhou

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

From: Chengming Zhou <[email protected]>

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 <[email protected]>
Closes: https://lore.kernel.org/all/ZN87UsqkWcFLDxea@swlinux02/
Tested-by: Leo Yu-Chi Liang <[email protected]>
Reviewed-by: Vincent Guittot <[email protected]>
Signed-off-by: Chengming Zhou <[email protected]>
---
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


Subject: [tip: sched/core] sched/fair: Fix cfs_rq_is_decayed() on !SMP

The following commit has been merged into the sched/core branch of tip:

Commit-ID: c0490bc9bb62d9376f3dd4ec28e03ca0fef97152
Gitweb: https://git.kernel.org/tip/c0490bc9bb62d9376f3dd4ec28e03ca0fef97152
Author: Chengming Zhou <[email protected]>
AuthorDate: Wed, 13 Sep 2023 13:20:31
Committer: Ingo Molnar <[email protected]>
CommitterDate: Fri, 15 Sep 2023 14:24:00 +02:00

sched/fair: Fix cfs_rq_is_decayed() on !SMP

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

But sched debug interface uses it to print per-cfs_rq stats.

This patch fixes the !SMP version of 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 <[email protected]>
Signed-off-by: Chengming Zhou <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Leo Yu-Chi Liang <[email protected]>
Reviewed-by: Vincent Guittot <[email protected]>
Closes: https://lore.kernel.org/all/ZN87UsqkWcFLDxea@swlinux02/
Link: https://lore.kernel.org/r/[email protected]
---
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 41cfd61..c893721 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4866,7 +4866,7 @@ 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