s390/cio/chp : Remove deprecated create_singlethread_workqueue
Subsystems (2)
PATCH 1/1 s390/cio/chp : Remove deprecated create_singlethread_workqueue
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.
--- drivers/s390/cio/chp.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-)
drivers/s390/cio/chp.c +2 -9
@@ -47,8 +47,6 @@ static DEFINE_MUTEX(info_lock);/* Time after which channel-path status may be outdated.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
Sebastian Ott
AppliedQuoted 17 lines · Bhaktipriya Shridhar
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 ofsystem_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_wqallows 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.
Quoted 1 line
Signed-off-by Bhaktipriya Shridhar <[email protected]>
Applied, thanks!
Sebastian