* [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP
@ 2023-09-13 13:20 chengming.zhou
2023-09-15 12:26 ` [tip: sched/core] " tip-bot2 for Chengming Zhou
0 siblings, 1 reply; 5+ messages in thread
From: chengming.zhou @ 2023-09-13 13:20 UTC (permalink / raw)
To: mingo, peterz
Cc: linux-kernel, chengming.zhou, Chengming Zhou, Leo Yu-Chi Liang,
Vincent Guittot
From: Chengming Zhou <zhouchengming@bytedance.com>
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@andestech.com>
Closes: https://lore.kernel.org/all/ZN87UsqkWcFLDxea@swlinux02/
Tested-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* [tip: sched/core] sched/fair: Fix cfs_rq_is_decayed() on !SMP
2023-09-13 13:20 [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP chengming.zhou
@ 2023-09-15 12:26 ` tip-bot2 for Chengming Zhou
0 siblings, 0 replies; 5+ messages in thread
From: tip-bot2 for Chengming Zhou @ 2023-09-15 12:26 UTC (permalink / raw)
To: linux-tip-commits
Cc: Leo Yu-Chi Liang, Chengming Zhou, Ingo Molnar, Vincent Guittot,
x86, linux-kernel
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 <zhouchengming@bytedance.com>
AuthorDate: Wed, 13 Sep 2023 13:20:31
Committer: Ingo Molnar <mingo@kernel.org>
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 <ycliang@andestech.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Closes: https://lore.kernel.org/all/ZN87UsqkWcFLDxea@swlinux02/
Link: https://lore.kernel.org/r/20230913132031.2242151-1-chengming.zhou@linux.dev
---
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
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP
2023-08-18 13:21 ` [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP chengming.zhou
2023-08-21 1:29 ` Leo Liang
@ 2023-08-21 11:59 ` Vincent Guittot
1 sibling, 0 replies; 5+ messages in thread
From: Vincent Guittot @ 2023-08-21 11:59 UTC (permalink / raw)
To: chengming.zhou
Cc: mingo, peterz, ycliang, juri.lelli, dietmar.eggemann, rostedt,
bsegall, mgorman, bristot, vschneid, zhouchengming, linux-kernel
On Fri, 18 Aug 2023 at 15:22, <chengming.zhou@linux.dev> wrote:
>
> From: Chengming Zhou <zhouchengming@bytedance.com>
>
> 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 Liang <ycliang@andestech.com>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> 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 a80a73909dc2..05e004515fde 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4654,7 +4654,7 @@ 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
> --
> 2.41.0
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP
2023-08-18 13:21 ` [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP chengming.zhou
@ 2023-08-21 1:29 ` Leo Liang
2023-08-21 11:59 ` Vincent Guittot
1 sibling, 0 replies; 5+ messages in thread
From: Leo Liang @ 2023-08-21 1:29 UTC (permalink / raw)
To: chengming.zhou
Cc: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, bristot, vschneid, zhouchengming,
linux-kernel
Hi Chengming,
On Fri, Aug 18, 2023 at 09:21:48PM +0800, chengming.zhou@linux.dev wrote:
> From: Chengming Zhou <zhouchengming@bytedance.com>
>
> 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 Liang <ycliang@andestech.com>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
> ---
> kernel/sched/fair.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Thanks for the quick patch!
Tested-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Best regards,
Leo
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP
2023-08-18 9:35 PROBLEM: LTP cfs_bandwidth01 test bumped into SCHED_WARN_ON after de-selecting CONFIG_SMP Leo Liang
@ 2023-08-18 13:21 ` chengming.zhou
2023-08-21 1:29 ` Leo Liang
2023-08-21 11:59 ` Vincent Guittot
0 siblings, 2 replies; 5+ messages in thread
From: chengming.zhou @ 2023-08-18 13:21 UTC (permalink / raw)
To: mingo, peterz, ycliang
Cc: juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall,
mgorman, bristot, vschneid, zhouchengming, linux-kernel
From: Chengming Zhou <zhouchengming@bytedance.com>
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 Liang <ycliang@andestech.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
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 a80a73909dc2..05e004515fde 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4654,7 +4654,7 @@ 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
--
2.41.0
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-08-18 9:35 PROBLEM: LTP cfs_bandwidth01 test bumped into SCHED_WARN_ON after de-selecting CONFIG_SMP Leo Liang
2023-08-18 13:21 ` [PATCH v2] sched/fair: Fix cfs_rq_is_decayed() on !SMP chengming.zhou
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