* [PATCH] s390/cio/chp : Remove deprecated create_singlethread_workqueue
@ 2016-07-16 8:48 Bhaktipriya Shridhar
2016-07-16 10:35 ` Sebastian Ott
0 siblings, 1 reply; 2+ messages in thread
From: Bhaktipriya Shridhar @ 2016-07-16 8:48 UTC (permalink / raw)
To: Sebastian Ott, Peter Oberparleiter, Martin Schwidefsky, Heiko Carstens
Cc: linux-s390, linux-kernel, Tejun Heo
The workqueue "chp_wq" is involved in performing pending
configure tasks for channel paths.
It has a single work item(&cfg_work) and hence doesn't require
ordering. Also, it is not being used on a memory reclaim path.
Hence, the singlethreaded workqueue has been replaced with the use of
system_wq.
System workqueues have been able to handle high level of concurrency
for a long time now and hence it's not required to have a singlethreaded
workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
created with create_singlethread_workqueue(), system_wq allows multiple
work items to overlap executions even on the same CPU; however, a
per-cpu workqueue doesn't have any CPU locality or global ordering
guarantee unless the target CPU is explicitly specified and thus the
increase of local concurrency shouldn't make any difference.
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
---
drivers/s390/cio/chp.c | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
index 50597f9..92413c4 100644
--- a/drivers/s390/cio/chp.c
+++ b/drivers/s390/cio/chp.c
@@ -47,8 +47,6 @@ static DEFINE_MUTEX(info_lock);
/* Time after which channel-path status may be outdated. */
static unsigned long chp_info_expires;
-/* Workqueue to perform pending configure tasks. */
-static struct workqueue_struct *chp_wq;
static struct work_struct cfg_work;
/* Wait queue for configure completion events. */
@@ -714,7 +712,7 @@ static void cfg_func(struct work_struct *work)
wake_up_interruptible(&cfg_wait_queue);
return;
}
- queue_work(chp_wq, &cfg_work);
+ schedule_work(&cfg_work);
}
/**
@@ -732,7 +730,7 @@ void chp_cfg_schedule(struct chp_id chpid, int configure)
cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
cfg_busy = 1;
mutex_unlock(&cfg_lock);
- queue_work(chp_wq, &cfg_work);
+ schedule_work(&cfg_work);
}
/**
@@ -766,11 +764,6 @@ static int __init chp_init(void)
ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
if (ret)
return ret;
- chp_wq = create_singlethread_workqueue("cio_chp");
- if (!chp_wq) {
- crw_unregister_handler(CRW_RSC_CPATH);
- return -ENOMEM;
- }
INIT_WORK(&cfg_work, cfg_func);
init_waitqueue_head(&cfg_wait_queue);
if (info_update())
--
2.1.4
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] s390/cio/chp : Remove deprecated create_singlethread_workqueue
2016-07-16 8:48 [PATCH] s390/cio/chp : Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
@ 2016-07-16 10:35 ` Sebastian Ott
0 siblings, 0 replies; 2+ messages in thread
From: Sebastian Ott @ 2016-07-16 10:35 UTC (permalink / raw)
To: Bhaktipriya Shridhar
Cc: Peter Oberparleiter, Martin Schwidefsky, Heiko Carstens,
linux-s390, linux-kernel, Tejun Heo
On Sat, 16 Jul 2016, Bhaktipriya Shridhar wrote:
> The workqueue "chp_wq" is involved in performing pending
> configure tasks for channel paths.
>
> It has a single work item(&cfg_work) and hence doesn't require
> ordering. Also, it is not being used on a memory reclaim path.
> Hence, the singlethreaded workqueue has been replaced with the use of
> system_wq.
>
> System workqueues have been able to handle high level of concurrency
> for a long time now and hence it's not required to have a singlethreaded
> workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
> created with create_singlethread_workqueue(), system_wq allows multiple
> work items to overlap executions even on the same CPU; however, a
> per-cpu workqueue doesn't have any CPU locality or global ordering
> guarantee unless the target CPU is explicitly specified and thus the
> increase of local concurrency shouldn't make any difference.
>
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Applied, thanks!
Sebastian
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2016-07-16 8:48 [PATCH] s390/cio/chp : Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
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