Re: [PATCH] thermal: core: Add WQ_PERCPU to alloc_workqueue users

[Rafael J. Wysocki]

On Thu, May 14, 2026 at 3:29 PM Marco Crivellari
<marco.crivellari@xxxxxxxx> wrote:
>
> This continues the effort to refactor workqueue APIs, which began with
> the introduction of new workqueues and a new alloc_workqueue flag in:
>
>    commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
>    commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")
>
> The refactoring is going to alter the default behavior of
> alloc_workqueue() to be unbound by 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. For more details see the Link tag below.
>
> In order to keep alloc_workqueue() behavior identical, explicitly request
> WQ_PERCPU.
>
> Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@xxxxxxxxxxxxx/
> Suggested-by: Tejun Heo <tj@xxxxxxxxxx>
> Signed-off-by: Marco Crivellari <marco.crivellari@xxxxxxxx>
> ---
>  drivers/thermal/thermal_core.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 2f4e2dc46b8f..691c5e749c3e 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -1889,7 +1889,8 @@ static int __init thermal_init(void)
>         if (result)
>                 goto error;
>
> -       thermal_wq = alloc_workqueue("thermal_events", WQ_POWER_EFFICIENT, 0);
> +       thermal_wq = alloc_workqueue("thermal_events",
> +                                    WQ_POWER_EFFICIENT | WQ_PERCPU, 0);

No, we actually don't want that here.  See

26fd03effa94 thermal: core: Adjust thermal_wq allocation flags

>         if (!thermal_wq) {
>                 result = -ENOMEM;
>                 goto unregister_netlink;
> --