* [PATCH] sched/fair: update comments in enqueue/dequeue_entity()
@ 2022-06-01 3:55 Chengming Zhou
2022-06-03 12:08 ` Vincent Guittot
0 siblings, 1 reply; 3+ messages in thread
From: Chengming Zhou @ 2022-06-01 3:55 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, bristot, vschneid
Cc: linux-kernel, Chengming Zhou
When reading the sched_avg related code, I found the comments in
enqueue/dequeue_entity() are not updated with the current code.
We don't add/subtract entity's runnable_avg from cfs_rq->runnable_avg
during enqueue/dequeue_entity(), those are done only for attach/detach.
This patch updates the comments to reflect the current code working.
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
kernel/sched/fair.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index b3371fa40548..e0cd4052e32f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4348,7 +4348,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
/*
* When enqueuing a sched_entity, we must:
* - Update loads to have both entity and cfs_rq synced with now.
- * - Add its load to cfs_rq->runnable_avg
+ * - For group_entity, update its runnable_weight to reflect the new
+ * h_nr_running of its group cfs_rq.
* - For group_entity, update its weight to reflect the new share of
* its group cfs_rq
* - Add its new weight to cfs_rq->load.weight
@@ -4433,7 +4434,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
/*
* When dequeuing a sched_entity, we must:
* - Update loads to have both entity and cfs_rq synced with now.
- * - Subtract its load from the cfs_rq->runnable_avg.
+ * - For group_entity, update its runnable_weight to reflect the new
+ * h_nr_running of its group cfs_rq.
* - Subtract its previous weight from cfs_rq->load.weight.
* - For group entity, update its weight to reflect the new share
* of its group cfs_rq.
--
2.36.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] sched/fair: update comments in enqueue/dequeue_entity()
2022-06-01 3:55 [PATCH] sched/fair: update comments in enqueue/dequeue_entity() Chengming Zhou
@ 2022-06-03 12:08 ` Vincent Guittot
2022-06-15 14:41 ` [External] " Chengming Zhou
0 siblings, 1 reply; 3+ messages in thread
From: Vincent Guittot @ 2022-06-03 12:08 UTC (permalink / raw)
To: Chengming Zhou
Cc: mingo, peterz, juri.lelli, dietmar.eggemann, rostedt, bsegall,
mgorman, bristot, vschneid, linux-kernel
On Wed, 1 Jun 2022 at 05:55, Chengming Zhou <zhouchengming@bytedance.com> wrote:
>
> When reading the sched_avg related code, I found the comments in
> enqueue/dequeue_entity() are not updated with the current code.
>
> We don't add/subtract entity's runnable_avg from cfs_rq->runnable_avg
> during enqueue/dequeue_entity(), those are done only for attach/detach.
>
> This patch updates the comments to reflect the current code working.
>
> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
> ---
> kernel/sched/fair.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index b3371fa40548..e0cd4052e32f 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4348,7 +4348,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
> /*
> * When enqueuing a sched_entity, we must:
> * - Update loads to have both entity and cfs_rq synced with now.
> - * - Add its load to cfs_rq->runnable_avg
> + * - For group_entity, update its runnable_weight to reflect the new
> + * h_nr_running of its group cfs_rq.
> * - For group_entity, update its weight to reflect the new share of
> * its group cfs_rq
> * - Add its new weight to cfs_rq->load.weight
> @@ -4433,7 +4434,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
> /*
> * When dequeuing a sched_entity, we must:
> * - Update loads to have both entity and cfs_rq synced with now.
> - * - Subtract its load from the cfs_rq->runnable_avg.
> + * - For group_entity, update its runnable_weight to reflect the new
> + * h_nr_running of its group cfs_rq.
> * - Subtract its previous weight from cfs_rq->load.weight.
> * - For group entity, update its weight to reflect the new share
> * of its group cfs_rq.
> --
> 2.36.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [External] Re: [PATCH] sched/fair: update comments in enqueue/dequeue_entity()
2022-06-03 12:08 ` Vincent Guittot
@ 2022-06-15 14:41 ` Chengming Zhou
0 siblings, 0 replies; 3+ messages in thread
From: Chengming Zhou @ 2022-06-15 14:41 UTC (permalink / raw)
To: peterz
Cc: Vincent Guittot, mingo, dietmar.eggemann, rostedt, bsegall,
mgorman, linux-kernel
On 2022/6/3 20:08, Vincent Guittot wrote:
> On Wed, 1 Jun 2022 at 05:55, Chengming Zhou <zhouchengming@bytedance.com> wrote:
>>
>> When reading the sched_avg related code, I found the comments in
>> enqueue/dequeue_entity() are not updated with the current code.
>>
>> We don't add/subtract entity's runnable_avg from cfs_rq->runnable_avg
>> during enqueue/dequeue_entity(), those are done only for attach/detach.
>>
>> This patch updates the comments to reflect the current code working.
>>
>> Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
>
> Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Hello Peter, would you mind picking up this little patch too?
Thanks.
>
>> ---
>> kernel/sched/fair.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index b3371fa40548..e0cd4052e32f 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -4348,7 +4348,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
>> /*
>> * When enqueuing a sched_entity, we must:
>> * - Update loads to have both entity and cfs_rq synced with now.
>> - * - Add its load to cfs_rq->runnable_avg
>> + * - For group_entity, update its runnable_weight to reflect the new
>> + * h_nr_running of its group cfs_rq.
>> * - For group_entity, update its weight to reflect the new share of
>> * its group cfs_rq
>> * - Add its new weight to cfs_rq->load.weight
>> @@ -4433,7 +4434,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
>> /*
>> * When dequeuing a sched_entity, we must:
>> * - Update loads to have both entity and cfs_rq synced with now.
>> - * - Subtract its load from the cfs_rq->runnable_avg.
>> + * - For group_entity, update its runnable_weight to reflect the new
>> + * h_nr_running of its group cfs_rq.
>> * - Subtract its previous weight from cfs_rq->load.weight.
>> * - For group entity, update its weight to reflect the new share
>> * of its group cfs_rq.
>> --
>> 2.36.1
>>
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2022-06-01 3:55 [PATCH] sched/fair: update comments in enqueue/dequeue_entity() Chengming Zhou
2022-06-03 12:08 ` Vincent Guittot
2022-06-15 14:41 ` [External] " Chengming Zhou
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