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From: "Richard W.M. Jones" <rjones@redhat.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Damien Le Moal <dlemoal@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, Jeff Moyer <jmoyer@redhat.com>,
	Jiri Jaburek <jjaburek@redhat.com>,
	Christoph Hellwig <hch@lst.de>,
	Bart Van Assche <bvanassche@acm.org>,
	Hannes Reinecke <hare@suse.de>,
	Chaitanya Kulkarni <kch@nvidia.com>
Subject: Re: [PATCH] block: elevator: avoid to load iosched module from this disk
Date: Sat, 7 Sep 2024 12:14:53 +0100	[thread overview]
Message-ID: <20240907111453.GA1450@redhat.com> (raw)
In-Reply-To: <ZtwyxukuaXAscXsz@fedora>

On Sat, Sep 07, 2024 at 07:02:30PM +0800, Ming Lei wrote:
> BTW, the issue can be reproduced 100% by:
> 
> echo "deadlock" > /sys/block/$ROOT_DISK/queue/scheduler

That doesn't reproduce it for me (reliably).  Although I'm not
surprised as this bug has been _very_ tricky to reproduce!  Sometimes
I think I have a definite reproducer, only for it to go away when some
tiny detail changes.

> > This seems like the neatest (or shortest) fix so far, but doesn't it
> > "mix up layers" by checking elv_iosched_store?
> 
> It is just one exception for 'scheduler' sysfs attribute wrt. freezing
> queue for storing, and the check can be done via the attribute
> name("scheduler") too.

Fair enough.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-builder quickly builds VMs from scratch
http://libguestfs.org/virt-builder.1.html


  reply	other threads:[~2024-09-07 11:15 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-07  1:43 [PATCH] block: elevator: avoid to load iosched module from this disk Ming Lei
2024-09-07  7:35 ` Richard W.M. Jones
2024-09-07  7:58   ` Ming Lei
2024-09-07  9:04     ` Damien Le Moal
2024-09-07  9:48       ` Ming Lei
2024-09-07 10:02         ` Richard W.M. Jones
2024-09-07 10:07           ` Ming Lei
2024-09-07 10:36             ` Richard W.M. Jones
2024-09-07 11:01               ` Richard W.M. Jones
2024-09-07 11:02               ` Ming Lei
2024-09-07 11:14                 ` Richard W.M. Jones [this message]
2024-09-08  0:02                   ` Damien Le Moal
2024-09-09  1:00                     ` Ming Lei
2024-09-09  1:01                     ` Ming Lei
2024-09-07  9:53       ` Richard W.M. Jones
2024-09-07 13:50       ` Jens Axboe
2024-09-09  1:24         ` Ming Lei
2024-09-09  1:56           ` Damien Le Moal
2024-09-09  1:59           ` Damien Le Moal
2024-09-09  2:16             ` Ming Lei

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