linux-kernel - [PATCH V4 3/4] block: queue work on unbound wq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <91239cde99aaba2715f63db1f88241d9f4a36e13.1364740180.git.viresh.kumar@linaro.org>
Date:	Sun, 31 Mar 2013 20:01:46 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	tj@...nel.org
Cc:	linaro-kernel@...ts.linaro.org, patches@...aro.org,
	robin.randhawa@....com, Steve.Bannister@....com,
	Liviu.Dudau@....com, charles.garcia-tobin@....com,
	arvind.chauhan@....com, davem@...emloft.net, airlied@...hat.com,
	axboe@...nel.dk, tglx@...utronix.de, peterz@...radead.org,
	mingo@...hat.com, rostedt@...dmis.org,
	linux-rt-users@...r.kernel.org, linux-kernel@...r.kernel.org,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH V4 3/4] block: queue work on unbound wq

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 UNBOUND versions.

Cc: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
 block/blk-core.c |  3 ++-
 block/blk-ioc.c  |  2 +-
 block/genhd.c    | 10 ++++++----
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 492242f..91cd486 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3186,7 +3186,8 @@ 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_UNBOUND, 0);
 	if (!kblockd_workqueue)
 		panic("Failed to create kblockd\n");
 
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 9c4bb82..5dd576d 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -144,7 +144,7 @@ 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_unbound_wq, &ioc->release_work);
 		else
 			free_ioc = true;
 		spin_unlock_irqrestore(&ioc->lock, flags);
diff --git a/block/genhd.c b/block/genhd.c
index a1ed52a..0f4470a 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1488,9 +1488,10 @@ 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_unbound_wq, &ev->dwork, 0);
 	else if (intv)
-		queue_delayed_work(system_freezable_wq, &ev->dwork, intv);
+		queue_delayed_work(system_freezable_unbound_wq, &ev->dwork,
+				intv);
 out_unlock:
 	spin_unlock_irqrestore(&ev->lock, flags);
 }
@@ -1533,7 +1534,7 @@ 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_unbound_wq, &ev->dwork, 0);
 	spin_unlock_irq(&ev->lock);
 }
 
@@ -1626,7 +1627,8 @@ 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_unbound_wq, &ev->dwork,
+				intv);
 
 	spin_unlock_irq(&ev->lock);
 
-- 
1.7.12.rc2.18.g61b472e

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/