From: Christoph Hellwig <hch@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Daniel Wagner <dwagner@suse.de>, Mike Galbraith <efault@gmx.de>,
Christoph Hellwig <hch@infradead.org>,
Sagi Grimberg <sagi@grimberg.me>
Subject: Re: [PATCH 1/3] blk-mq: Don't complete on a remote CPU in force threaded mode
Date: Tue, 8 Dec 2020 13:10:49 +0000 [thread overview]
Message-ID: <20201208131049.GA22219@infradead.org> (raw)
In-Reply-To: <20201204191356.2516405-2-bigeasy@linutronix.de>
On Fri, Dec 04, 2020 at 08:13:54PM +0100, Sebastian Andrzej Siewior wrote:
> With force threaded interrupts enabled, raising softirq from an SMP
> function call will always result in waking the ksoftirqd thread. This is
> not optimal given that the thread runs at SCHED_OTHER priority.
>
> Completing the request in hard IRQ-context on PREEMPT_RT (which enforces
> the force threaded mode) is bad because the completion handler may
> acquire sleeping locks which violate the locking context.
>
> Disable request completing on a remote CPU in force threaded mode.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
next prev parent reply other threads:[~2020-12-08 13:11 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-04 19:13 [PATCH 0/3 v2] blk-mq: Don't complete in IRQ, use llist_head Sebastian Andrzej Siewior
2020-12-04 19:13 ` [PATCH 1/3] blk-mq: Don't complete on a remote CPU in force threaded mode Sebastian Andrzej Siewior
2020-12-08 13:10 ` Christoph Hellwig [this message]
2020-12-04 19:13 ` [PATCH 2/3] blk-mq: Always complete remote completions requests in softirq Sebastian Andrzej Siewior
2020-12-07 23:52 ` Jens Axboe
2020-12-08 8:22 ` Sebastian Andrzej Siewior
2020-12-08 8:44 ` Daniel Wagner
2020-12-08 11:36 ` Daniel Wagner
2020-12-08 11:49 ` Sebastian Andrzej Siewior
2020-12-08 12:41 ` Daniel Wagner
2020-12-08 12:52 ` Sebastian Andrzej Siewior
2020-12-08 12:57 ` Sebastian Andrzej Siewior
2020-12-08 13:27 ` Daniel Wagner
2020-12-17 16:45 ` Jens Axboe
2020-12-17 16:49 ` Daniel Wagner
2020-12-17 16:54 ` Jens Axboe
2020-12-08 13:13 ` Christoph Hellwig
2020-12-17 16:43 ` Sebastian Andrzej Siewior
2020-12-17 16:55 ` Jens Axboe
2020-12-17 16:58 ` Sebastian Andrzej Siewior
2020-12-17 17:05 ` Daniel Wagner
2020-12-17 18:16 ` Daniel Wagner
2020-12-17 18:22 ` Jens Axboe
2020-12-17 18:41 ` Daniel Wagner
2020-12-17 18:46 ` Jens Axboe
2020-12-17 19:07 ` Daniel Wagner
2020-12-17 19:13 ` Jens Axboe
2020-12-17 19:15 ` Daniel Wagner
2020-12-04 19:13 ` [PATCH 3/3] blk-mq: Use llist_head for blk_cpu_done Sebastian Andrzej Siewior
2020-12-08 13:20 ` Christoph Hellwig
2020-12-08 13:28 ` Christoph Hellwig
2020-12-14 20:20 ` Sebastian Andrzej Siewior
-- strict thread matches above, loose matches on Subject: below --
2020-10-28 6:56 [PATCH RFC] blk-mq: Don't IPI requests on PREEMPT_RT Christoph Hellwig
2020-10-28 14:12 ` [PATCH 1/3] blk-mq: Don't complete on a remote CPU in force threaded mode Sebastian Andrzej Siewior
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