Re: [PATCH] sched/fair: update comments in enqueue/dequeue_entity()

From: Vincent Guittot
Date: Fri Jun 03 2022 - 08:08:49 EST


On Wed, 1 Jun 2022 at 05:55, Chengming Zhou <zhouchengming@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>

Acked-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>

> ---
> 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
>