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 <c...@laptop.org> Cc: linux-...@vger.kernel.org Signed-off-by: Viresh Kumar <viresh.ku...@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); } /* -- 1.7.12.rc2.18.g61b472e -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/