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block: queue work on power efficient wq

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Block layer uses workqueues for multiple purposes. 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 the
scheduler believes to be the most appropriate one.

This patch replaces normal workqueues with power efficient versions.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Viresh Kumar 2013-04-24 17:12:56 +05:30 committed by Tejun Heo
parent bbb47bdeae
commit 695588f945
3 changed files with 12 additions and 6 deletions
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3
block/blk-core.c
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@ -3180,7 +3180,8 @@ int __init blk_dev_init(void)
/* used for unplugging and affects IO latency/throughput - HIGHPRI */
kblockd_workqueue = alloc_workqueue("kblockd",
WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
WQ_MEM_RECLAIM | WQ_HIGHPRI |
WQ_POWER_EFFICIENT, 0);
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");

3
block/blk-ioc.c
View file

@ -144,7 +144,8 @@ void put_io_context(struct io_context *ioc)
if (atomic_long_dec_and_test(&ioc->refcount)) {
spin_lock_irqsave(&ioc->lock, flags);
if (!hlist_empty(&ioc->icq_list))
schedule_work(&ioc->release_work);
queue_work(system_power_efficient_wq,
&ioc->release_work);
else
free_ioc = true;
spin_unlock_irqrestore(&ioc->lock, flags);

12
block/genhd.c
View file

@ -1489,9 +1489,11 @@ static void __disk_unblock_events(struct gendisk *disk, bool check_now)
intv = disk_events_poll_jiffies(disk);
set_timer_slack(&ev->dwork.timer, intv / 4);
if (check_now)
queue_delayed_work(system_freezable_wq, &ev->dwork, 0);
queue_delayed_work(system_freezable_power_efficient_wq,
&ev->dwork, 0);
else if (intv)
queue_delayed_work(system_freezable_wq, &ev->dwork, intv);
queue_delayed_work(system_freezable_power_efficient_wq,
&ev->dwork, intv);
out_unlock:
spin_unlock_irqrestore(&ev->lock, flags);
}
@ -1534,7 +1536,8 @@ void disk_flush_events(struct gendisk *disk, unsigned int mask)
spin_lock_irq(&ev->lock);
ev->clearing |= mask;
if (!ev->block)
mod_delayed_work(system_freezable_wq, &ev->dwork, 0);
mod_delayed_work(system_freezable_power_efficient_wq,
&ev->dwork, 0);
spin_unlock_irq(&ev->lock);
}
@ -1627,7 +1630,8 @@ static void disk_check_events(struct disk_events *ev,
intv = disk_events_poll_jiffies(disk);
if (!ev->block && intv)
queue_delayed_work(system_freezable_wq, &ev->dwork, intv);
queue_delayed_work(system_freezable_power_efficient_wq,
&ev->dwork, intv);
spin_unlock_irq(&ev->lock);