* [PATCH 0/2] Remove improper workqueue usage
@ 2016-07-16 9:10 Bhaktipriya Shridhar
2016-07-16 9:11 ` [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue Bhaktipriya Shridhar
2016-07-16 9:13 ` [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
0 siblings, 2 replies; 5+ messages in thread
From: Bhaktipriya Shridhar @ 2016-07-16 9:10 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Geunyoung Kim, Junghak Sung, Hans Verkuil,
Inki Dae
Cc: linux-media, linux-kernel, Tejun Heo
This patch set fixes the improper usage of the workqueue API.
This includes dropping the freeing of workqueue and removing the deprecated
create_singlethread_workqueue instance.
Bhaktipriya Shridhar (2):
[media] cx25821: Drop Freeing of Workqueue
[media] cx25821: Remove deprecated create_singlethread_workqueue
drivers/media/pci/cx25821/cx25821-audio-upstream.c | 13 ++-----------
drivers/media/pci/cx25821/cx25821.h | 1 -
2 files changed, 2 insertions(+), 12 deletions(-)
--
2.1.4
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue
2016-07-16 9:10 [PATCH 0/2] Remove improper workqueue usage Bhaktipriya Shridhar
@ 2016-07-16 9:11 ` Bhaktipriya Shridhar
2016-07-18 23:55 ` Tejun Heo
2016-07-16 9:13 ` [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
1 sibling, 1 reply; 5+ messages in thread
From: Bhaktipriya Shridhar @ 2016-07-16 9:11 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Geunyoung Kim, Junghak Sung, Hans Verkuil,
Inki Dae
Cc: linux-media, linux-kernel, Tejun Heo
Workqueues shouldn't be freed. destroy_workqueue should be used instead.
destroy_workqueue safely destroys a workqueue and ensures that all pending
work items are done before destroying the workqueue.
Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
---
drivers/media/pci/cx25821/cx25821-audio-upstream.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/pci/cx25821/cx25821-audio-upstream.c b/drivers/media/pci/cx25821/cx25821-audio-upstream.c
index 68dbc2d..05bd957 100644
--- a/drivers/media/pci/cx25821/cx25821-audio-upstream.c
+++ b/drivers/media/pci/cx25821/cx25821-audio-upstream.c
@@ -242,7 +242,7 @@ void cx25821_stop_upstream_audio(struct cx25821_dev *dev)
dev->_audioframe_count = 0;
dev->_audiofile_status = END_OF_FILE;
- kfree(dev->_irq_audio_queues);
+ destroy_workqueue(dev->_irq_audio_queues);
dev->_irq_audio_queues = NULL;
kfree(dev->_audiofilename);
--
2.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue
2016-07-16 9:10 [PATCH 0/2] Remove improper workqueue usage Bhaktipriya Shridhar
2016-07-16 9:11 ` [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue Bhaktipriya Shridhar
@ 2016-07-16 9:13 ` Bhaktipriya Shridhar
2016-07-18 23:56 ` Tejun Heo
1 sibling, 1 reply; 5+ messages in thread
From: Bhaktipriya Shridhar @ 2016-07-16 9:13 UTC (permalink / raw)
To: Mauro Carvalho Chehab, Geunyoung Kim, Junghak Sung, Hans Verkuil,
Inki Dae
Cc: linux-media, linux-kernel, Tejun Heo
The workqueue "_irq_audio_queues" runs the audio upstream handler.
It has a single work item(&dev->_audio_work_entry) 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/media/pci/cx25821/cx25821-audio-upstream.c | 11 +----------
drivers/media/pci/cx25821/cx25821.h | 1 -
2 files changed, 1 insertion(+), 11 deletions(-)
diff --git a/drivers/media/pci/cx25821/cx25821-audio-upstream.c b/drivers/media/pci/cx25821/cx25821-audio-upstream.c
index 05bd957..1a86dff 100644
--- a/drivers/media/pci/cx25821/cx25821-audio-upstream.c
+++ b/drivers/media/pci/cx25821/cx25821-audio-upstream.c
@@ -446,8 +446,7 @@ static int cx25821_audio_upstream_irq(struct cx25821_dev *dev, int chan_num,
dev->_audioframe_index = dev->_last_index_irq;
- queue_work(dev->_irq_audio_queues,
- &dev->_audio_work_entry);
+ schedule_work(&dev->_audio_work_entry);
}
if (dev->_is_first_audio_frame) {
@@ -639,14 +638,6 @@ int cx25821_audio_upstream_init(struct cx25821_dev *dev, int channel_select)
/* Work queue */
INIT_WORK(&dev->_audio_work_entry, cx25821_audioups_handler);
- dev->_irq_audio_queues =
- create_singlethread_workqueue("cx25821_audioworkqueue");
-
- if (!dev->_irq_audio_queues) {
- printk(KERN_DEBUG
- pr_fmt("ERROR: create_singlethread_workqueue() for Audio FAILED!\n"));
- return -ENOMEM;
- }
dev->_last_index_irq = 0;
dev->_audio_is_running = 0;
diff --git a/drivers/media/pci/cx25821/cx25821.h b/drivers/media/pci/cx25821/cx25821.h
index a513b68..c813d88 100644
--- a/drivers/media/pci/cx25821/cx25821.h
+++ b/drivers/media/pci/cx25821/cx25821.h
@@ -294,7 +294,6 @@ struct cx25821_dev {
u32 audio_upstream_riscbuf_size;
u32 audio_upstream_databuf_size;
int _audioframe_index;
- struct workqueue_struct *_irq_audio_queues;
struct work_struct _audio_work_entry;
char *input_audiofilename;
--
2.1.4
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue
2016-07-16 9:11 ` [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue Bhaktipriya Shridhar
@ 2016-07-18 23:55 ` Tejun Heo
0 siblings, 0 replies; 5+ messages in thread
From: Tejun Heo @ 2016-07-18 23:55 UTC (permalink / raw)
To: Bhaktipriya Shridhar
Cc: Mauro Carvalho Chehab, Geunyoung Kim, Junghak Sung, Hans Verkuil,
Inki Dae, linux-media, linux-kernel
On Sat, Jul 16, 2016 at 02:41:49PM +0530, Bhaktipriya Shridhar wrote:
> Workqueues shouldn't be freed. destroy_workqueue should be used instead.
> destroy_workqueue safely destroys a workqueue and ensures that all pending
> work items are done before destroying the workqueue.
>
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
This needs to be marked for stable.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue
2016-07-16 9:13 ` [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
@ 2016-07-18 23:56 ` Tejun Heo
0 siblings, 0 replies; 5+ messages in thread
From: Tejun Heo @ 2016-07-18 23:56 UTC (permalink / raw)
To: Bhaktipriya Shridhar
Cc: Mauro Carvalho Chehab, Geunyoung Kim, Junghak Sung, Hans Verkuil,
Inki Dae, linux-media, linux-kernel
On Sat, Jul 16, 2016 at 02:43:20PM +0530, Bhaktipriya Shridhar wrote:
> The workqueue "_irq_audio_queues" runs the audio upstream handler.
> It has a single work item(&dev->_audio_work_entry) 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.
The patch seems to be missing update to wq destruction path.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2016-07-18 23:56 UTC | newest]
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2016-07-16 9:10 [PATCH 0/2] Remove improper workqueue usage Bhaktipriya Shridhar
2016-07-16 9:11 ` [PATCH 1/2] [media] cx25821: Drop Freeing of Workqueue Bhaktipriya Shridhar
2016-07-18 23:55 ` Tejun Heo
2016-07-16 9:13 ` [PATCH 2/2] [media] cx25821: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
2016-07-18 23:56 ` Tejun Heo
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