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From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org
Subject: Re: [PATCH 1/2] block: avoid to hold q->limits_lock across APIs for atomic update queue limits
Date: Tue, 17 Dec 2024 15:05:48 +0800	[thread overview]
Message-ID: <Z2EizLh58zjrGUOw@fedora> (raw)
In-Reply-To: <20241217044056.GA15764@lst.de>

On Tue, Dec 17, 2024 at 05:40:56AM +0100, Christoph Hellwig wrote:
> On Tue, Dec 17, 2024 at 09:52:51AM +0800, Ming Lei wrote:
> > The local copy can be updated in any way with any data, so does another
> > concurrent update on q->limits really matter?
> 
> Yes, because that means one of the updates get lost even if it is
> for entirely separate fields.

Right, but the limits are still valid anytime.

Any suggestion for fixing this deadlock?

One idea is to add queue_limits_start_try_update() and apply it in
sysfs ->store(), in which update failure could be tolerable.


Thanks,
Ming


  reply	other threads:[~2024-12-17  7:06 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-16  8:02 [PATCH 0/2] block: fix deadlock caused by atomic limits update Ming Lei
2024-12-16  8:02 ` [PATCH 1/2] block: avoid to hold q->limits_lock across APIs for atomic update queue limits Ming Lei
2024-12-16 15:49   ` Christoph Hellwig
2024-12-17  1:52     ` Ming Lei
2024-12-17  4:40       ` Christoph Hellwig
2024-12-17  7:05         ` Ming Lei [this message]
2024-12-17  7:19           ` Christoph Hellwig
2024-12-17  7:30             ` Ming Lei
2024-12-17 16:07               ` Damien Le Moal
2024-12-18  2:09                 ` Ming Lei
2024-12-18 11:33                   ` Nilay Shroff
2024-12-18 13:40                     ` Ming Lei
2024-12-18 14:05                       ` Nilay Shroff
2024-12-18 14:57                         ` Damien Le Moal
2024-12-19  6:20                           ` Christoph Hellwig
2024-12-19  7:16                             ` Nilay Shroff
2024-12-21 13:03                             ` Nilay Shroff
2024-12-30  9:02                               ` Ming Lei
2024-12-30 23:29                                 ` Damien Le Moal
2025-01-01 11:17                                   ` Nilay Shroff
2024-12-19  6:17                         ` Christoph Hellwig
2024-12-19  6:15                   ` Christoph Hellwig
2024-12-16  8:02 ` [PATCH 2/2] block: remove queue_limits_cancel_update() Ming Lei

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