diff options
| author | Marco Crivellari <marco.crivellari@suse.com> | 2025-10-31 10:56:43 +0100 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2025-11-12 21:28:26 -0500 |
| commit | f76e4e1e836df41f602fa4c85f64f09e2a99266e (patch) | |
| tree | 5bc3d46c1e90d6d1a6c0dd811bc405ff2a564095 | |
| parent | afad6b34defed8ca19f8593b692024e8e296287f (diff) | |
scsi: scsi_transport_fc: 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>
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Link: https://patch.msgid.link/20251031095643.74246-5-marco.crivellari@suse.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
| -rw-r--r-- | drivers/scsi/scsi_transport_fc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index 3a821afee9bc..987befb02408 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -441,7 +441,8 @@ static int fc_host_setup(struct transport_container *tc, struct device *dev, fc_host->next_vport_number = 0; fc_host->npiv_vports_inuse = 0; - fc_host->work_q = alloc_workqueue("fc_wq_%d", 0, 0, shost->host_no); + fc_host->work_q = alloc_workqueue("fc_wq_%d", WQ_PERCPU, 0, + shost->host_no); if (!fc_host->work_q) return -ENOMEM; @@ -3088,7 +3089,7 @@ fc_remote_port_create(struct Scsi_Host *shost, int channel, spin_unlock_irqrestore(shost->host_lock, flags); - rport->devloss_work_q = alloc_workqueue("fc_dl_%d_%d", 0, 0, + rport->devloss_work_q = alloc_workqueue("fc_dl_%d_%d", WQ_PERCPU, 0, shost->host_no, rport->number); if (!rport->devloss_work_q) { printk(KERN_ERR "FC Remote Port alloc_workqueue failed\n"); |