diff options
| author | Marco Crivellari <marco.crivellari@suse.com> | 2025-10-31 10:56:42 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2025-11-12 21:28:26 -0500 |
| commit | afad6b34defed8ca19f8593b692024e8e296287f (patch) | |
| tree | 51d91e9c306ce9c99d0b3a61f48d37c90f72b6d7 | |
| parent | 5ca003bb438197791f6394d5c05e5abf403ada24 (diff) | |
scsi: scsi_dh_alua: WQ_PERCPU added to alloc_workqueue() users
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.
This lack of consistentcy cannot be addressed without refactoring the API.
alloc_workqueue() treats all queues as per-CPU by default, while unbound
workqueues must opt-in via WQ_UNBOUND.
This default is suboptimal: most workloads benefit from unbound queues,
allowing the scheduler to place worker threads where they’re needed and
reducing noise when CPUs are isolated.
This change adds a new WQ_PERCPU flag to explicitly request
alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified.
With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU.
Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://patch.msgid.link/20251031095643.74246-4-marco.crivellari@suse.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/scsi/device_handler/scsi_dh_alua.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c index 1bf5948d1188..6fd89ae33059 100644 --- a/drivers/scsi/device_handler/scsi_dh_alua.c +++ b/drivers/scsi/device_handler/scsi_dh_alua.c @@ -1300,7 +1300,7 @@ static int __init alua_init(void) { int r; - kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM, 0); + kaluad_wq = alloc_workqueue("kaluad", WQ_MEM_RECLAIM | WQ_PERCPU, 0); if (!kaluad_wq) return -ENOMEM; |