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wifi: rtw88: add WQ_UNBOUND to alloc_workqueue users

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Currently if a user enqueues 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 consistency cannot be addressed without refactoring the API.
For more details see the Link tag below.

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 continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

commit 128ea9f6cc ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566 ("workqueue: Add new WQ_PERCPU flag")

This change adds the WQ_UNBOUND flag to explicitly request
alloc_workqueue() to be unbound, because this specific workload has no
benefit being per-cpu.

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://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20251118102032.54375-3-marco.crivellari@suse.com
This commit is contained in:
Marco Crivellari
2025-11-18 11:20:32 +01:00
committed by Ping-Ke Shih
parent 7cbec00dc7
commit 9c194fe462
1 changed files with 2 additions and 1 deletions
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3
drivers/net/wireless/realtek/rtw88/usb.c
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@@ -965,7 +965,8 @@ static int rtw_usb_init_rx(struct rtw_dev *rtwdev)
struct sk_buff *rx_skb;
int i;
rtwusb->rxwq = alloc_workqueue("rtw88_usb: rx wq", WQ_BH, 0);
rtwusb->rxwq = alloc_workqueue("rtw88_usb: rx wq", WQ_BH | WQ_UNBOUND,
0);
if (!rtwusb->rxwq) {
rtw_err(rtwdev, "failed to create RX work queue\n");
return -ENOMEM;