Re: [PATCH] sched/fair: remove the spin_lock operations

From: Benjamin Segall
Date: Fri Oct 30 2020 - 14:48:07 EST


Hui Su <sh_def@xxxxxxx> writes:

> Since 'ab93a4bc955b ("sched/fair: Remove
> distribute_running fromCFS bandwidth")',there is
> nothing to protect between raw_spin_lock_irqsave/store()
> in do_sched_cfs_slack_timer().
>
> So remove it.

Reviewed-by: Ben Segall <bsegall@xxxxxxxxxx>

(I might nitpick the subject to be clear that it should be trivial
because the lock area is empty, or call them dead or something, but it's
not all that important)

>
> Signed-off-by: Hui Su <sh_def@xxxxxxx>
> ---
> kernel/sched/fair.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 290f9e38378c..5ecbf5e63198 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -5105,9 +5105,6 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
> return;
>
> distribute_cfs_runtime(cfs_b);
> -
> - raw_spin_lock_irqsave(&cfs_b->lock, flags);
> - raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
> }
>
> /*