From: Lai Jiangshan <jiangshanlai@gmail.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2 2/2] workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t
Date: Thu, 28 May 2020 08:33:03 +0800 [thread overview]
Message-ID: <CAJhGHyCxR2RgvwMQrNT-82qHKJ-Cok4d2sWy4q7mgtZ_CtXA+w@mail.gmail.com> (raw)
In-Reply-To: <20200527194633.1660952-3-bigeasy@linutronix.de>
On Thu, May 28, 2020 at 3:47 AM Sebastian Andrzej Siewior
<bigeasy@linutronix.de> 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@linutronix.de>
> ---
> kernel/workqueue.c | 176 ++++++++++++++++++++++-----------------------
> 1 file changed, 88 insertions(+), 88 deletions(-)
>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
next prev parent reply other threads:[~2020-05-28 0:33 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-27 19:46 [PATCH v2 0/2] workqueue: Make the workqueue code PREEMPT_RT safe Sebastian Andrzej Siewior
2020-05-27 19:46 ` [PATCH v2 1/2] workqueue: Use rcuwait for wq_manager_wait Sebastian Andrzej Siewior
2020-05-28 3:06 ` [PATCH 1/2] workqueue: pin the pool while it is managing Lai Jiangshan
2020-05-28 3:06 ` [PATCH 2/2] workqueue: remove useless POOL_MANAGER_ACTIVE Lai Jiangshan
2020-05-28 8:08 ` [PATCH 1/2] workqueue: pin the pool while it is managing Sebastian Andrzej Siewior
2020-05-28 8:35 ` Lai Jiangshan
2020-05-28 14:35 ` Tejun Heo
2020-05-29 5:33 ` Lai Jiangshan
2020-05-27 19:46 ` [PATCH v2 2/2] workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t Sebastian Andrzej Siewior
2020-05-28 0:33 ` Lai Jiangshan [this message]
2020-05-29 14:04 ` Tejun Heo
2020-05-27 22:57 ` [PATCH v2 0/2] workqueue: Make the workqueue code PREEMPT_RT safe Linus Torvalds
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