Re: [PATCH v2 2/2] workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t

From: Tejun Heo
Date: Fri May 29 2020 - 10:04:26 EST


On Wed, May 27, 2020 at 09:46:33PM +0200, Sebastian Andrzej Siewior wrote:
> The workqueue code has it's internal spinlocks (pool::lock), which
> are acquired on most workqueue operations. These spinlocks are
> converted to 'sleeping' spinlocks on a RT-kernel.
>
> Workqueue functions can be invoked from contexts which are truly atomic
> even on a PREEMPT_RT enabled kernel. Taking sleeping locks from such
> contexts is forbidden.
>
> The pool::lock hold times are bound and the code sections are
> relatively short, which allows to convert pool::lock and as a
> consequence wq_mayday_lock to raw spinlocks which are truly spinning
> locks even on a PREEMPT_RT kernel.
>
> With the previous conversion of the manager waitqueue to a simple
> waitqueue workqueues are now fully RT compliant.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

Applied 1-2 to wq/for-5.8.

Thanks.

--
tejun