Re: [PATCH V3 5/7] mmc: queue work on any cpu

[Chris Ball <cjb@laptop.org>]

Hi,

On Mon, Mar 18 2013, Viresh Kumar wrote:
> mmc uses workqueues for running mmc_rescan(). There is no real dependency of
> scheduling these on the cpu which scheduled them.
>
> On a idle system, it is observed that and idle cpu wakes up many times just to
> service this work. It would be better if we can schedule it on a cpu which isn't
> idle to save on power.
>
> By idle cpu (from scheduler's perspective) we mean:
> - Current task is idle task
> - nr_running == 0
> - wake_list is empty
>
> This patch replaces the queue_delayed_work() with
> queue_delayed_work_on_any_cpu() siblings.
>
> This routine would look for the closest (via scheduling domains) non-idle cpu
> (non-idle from schedulers perspective). If the current cpu is not idle or all
> cpus are idle, work will be scheduled on local cpu.
>
> Cc: Chris Ball <cjb@laptop.org>
> Cc: linux-mmc@vger.kernel.org
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  drivers/mmc/core/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 9290bb5..adf331a 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -85,7 +85,7 @@ MODULE_PARM_DESC(
>  static int mmc_schedule_delayed_work(struct delayed_work *work,
>  				     unsigned long delay)
>  {
> -	return queue_delayed_work(workqueue, work, delay);
> +	return queue_delayed_work_on_any_cpu(workqueue, work, delay);
>  }
>  
>  /*

Thanks, pushed to mmc-next for 3.10.

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child