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wifi: libertas: 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 add a new WQ_PERCPU flag, to explicitly request the use of
the per-CPU behavior. Both flags coexist for one release cycle to allow
callers to transition their calls.

Once migration is complete, WQ_UNBOUND can be removed and unbound will
become the implicit default.

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.

All existing users have been updated accordingly.

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Link: https://patch.msgid.link/20250922102407.186660-2-marco.crivellari@suse.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
pull/1354/merge
Marco Crivellari 2025-09-22 12:24:07 +02:00 committed by Johannes Berg
parent 17f34ab55a
commit 1e06a13751
3 changed files with 5 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/net/wireless/marvell/libertas/if_sdio.c
View File

@ -1181,7 +1181,8 @@ static int if_sdio_probe(struct sdio_func *func,
spin_lock_init(&card->lock);
INIT_LIST_HEAD(&card->packets);
card->workqueue = alloc_workqueue("libertas_sdio", WQ_MEM_RECLAIM, 0);
card->workqueue = alloc_workqueue("libertas_sdio",
WQ_MEM_RECLAIM | WQ_PERCPU, 0);
if (unlikely(!card->workqueue)) {
ret = -ENOMEM;
goto err_queue;

3
drivers/net/wireless/marvell/libertas/if_spi.c
View File

@ -1153,7 +1153,8 @@ static int if_spi_probe(struct spi_device *spi)
priv->fw_ready = 1;
/* Initialize interrupt handling stuff. */
card->workqueue = alloc_workqueue("libertas_spi", WQ_MEM_RECLAIM, 0);
card->workqueue = alloc_workqueue("libertas_spi",
WQ_MEM_RECLAIM | WQ_PERCPU, 0);
if (!card->workqueue) {
err = -ENOMEM;
goto remove_card;

2
drivers/net/wireless/marvell/libertas_tf/main.c
View File

@ -708,7 +708,7 @@ EXPORT_SYMBOL_GPL(lbtf_bcn_sent);
static int __init lbtf_init_module(void)
{
lbtf_deb_enter(LBTF_DEB_MAIN);
lbtf_wq = alloc_workqueue("libertastf", WQ_MEM_RECLAIM, 0);
lbtf_wq = alloc_workqueue("libertastf", WQ_MEM_RECLAIM | WQ_PERCPU, 0);
if (lbtf_wq == NULL) {
printk(KERN_ERR "libertastf: couldn't create workqueue\n");
return -ENOMEM;