From: Mike Snitzer <snitzer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Ming Lei <ming.lei@redhat.com>,
Bart Van Assche <Bart.VanAssche@wdc.com>,
"dm-devel@redhat.com" <dm-devel@redhat.com>,
"hch@infradead.org" <hch@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"osandov@fb.com" <osandov@fb.com>
Subject: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle
Date: Fri, 19 Jan 2018 11:47:22 -0500 [thread overview]
Message-ID: <20180119164722.GA29449@redhat.com> (raw)
In-Reply-To: <26833249-cadf-ba9c-1128-0bcb70ceb9e1@kernel.dk>
On Fri, Jan 19 2018 at 11:41am -0500,
Jens Axboe <axboe@kernel.dk> wrote:
> On 1/19/18 9:37 AM, Ming Lei wrote:
> > On Fri, Jan 19, 2018 at 09:27:46AM -0700, Jens Axboe wrote:
> >> On 1/19/18 9:26 AM, Ming Lei wrote:
> >>> On Fri, Jan 19, 2018 at 09:19:24AM -0700, Jens Axboe wrote:
> >>
> >> There are no pending requests for this case, nothing to restart the
> >> queue. When you fail that blk_get_request(), you are idle, nothing
> >> is pending.
> >
> > I think we needn't worry about that, once a device is attached to
> > dm-rq, it can't be mounted any more, and usually user don't use the device
> > directly and by dm-mpath at the same time.
>
> Even if it doesn't happen for a normal dm setup, it is a case that
> needs to be handled. The request allocation is just one example of
> a wider scope resource that can be unavailable. If the driver returns
> NO_DEV_RESOURCE (or whatever name), it will be a possibility that
> the device itself is currently idle.
How would a driver's resources be exhausted yet the device is idle (so
as not to be able to benefit from RESTART)?
next prev parent reply other threads:[~2018-01-19 16:47 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 2:41 [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Ming Lei
2018-01-18 16:50 ` Bart Van Assche
2018-01-18 17:03 ` Mike Snitzer
2018-01-18 17:03 ` Mike Snitzer
2018-01-18 17:20 ` Bart Van Assche
2018-01-18 17:20 ` Bart Van Assche
2018-01-18 18:30 ` Mike Snitzer
2018-01-18 18:47 ` Bart Van Assche
2018-01-18 18:47 ` Bart Van Assche
2018-01-18 20:11 ` Jens Axboe
2018-01-18 20:11 ` Jens Axboe
2018-01-18 20:48 ` Mike Snitzer
2018-01-18 20:58 ` Bart Van Assche
2018-01-18 20:58 ` Bart Van Assche
2018-01-18 21:23 ` Mike Snitzer
2018-01-18 21:23 ` Mike Snitzer
2018-01-18 21:37 ` Laurence Oberman
2018-01-18 21:39 ` [dm-devel] " Bart Van Assche
2018-01-18 21:39 ` Bart Van Assche
2018-01-18 21:45 ` Laurence Oberman
2018-01-18 21:45 ` Laurence Oberman
2018-01-18 22:01 ` Mike Snitzer
2018-01-18 22:18 ` Laurence Oberman
2018-01-18 22:20 ` Laurence Oberman
2018-01-18 22:20 ` Laurence Oberman
2018-01-18 22:24 ` Bart Van Assche
2018-01-18 22:24 ` Bart Van Assche
2018-01-18 22:35 ` Laurence Oberman
2018-01-18 22:39 ` Jens Axboe
2018-01-18 22:55 ` Bart Van Assche
2018-01-18 22:55 ` Bart Van Assche
2018-01-18 22:20 ` Bart Van Assche
2018-01-18 22:20 ` Bart Van Assche
2018-01-23 9:22 ` [PATCH] block: neutralize blk_insert_cloned_request IO stall regression (was: Re: [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle) Mike Snitzer
2018-01-23 10:53 ` Ming Lei
2018-01-23 12:15 ` Mike Snitzer
2018-01-23 12:17 ` Ming Lei
2018-01-23 12:43 ` Mike Snitzer
2018-01-23 16:43 ` [PATCH] " Bart Van Assche
2018-01-23 16:43 ` Bart Van Assche
2018-01-19 2:32 ` [RFC PATCH] blk-mq: fixup RESTART when queue becomes idle Ming Lei
2018-01-19 4:02 ` Jens Axboe
2018-01-19 7:26 ` Ming Lei
2018-01-19 15:20 ` Bart Van Assche
2018-01-19 15:20 ` Bart Van Assche
2018-01-19 15:25 ` Jens Axboe
2018-01-19 15:33 ` Ming Lei
2018-01-19 16:06 ` Bart Van Assche
2018-01-19 16:06 ` Bart Van Assche
2018-01-19 15:24 ` Jens Axboe
2018-01-19 15:40 ` Ming Lei
2018-01-19 15:40 ` Ming Lei
2018-01-19 15:48 ` Jens Axboe
2018-01-19 16:05 ` Ming Lei
2018-01-19 16:19 ` Jens Axboe
2018-01-19 16:26 ` Ming Lei
2018-01-19 16:27 ` Jens Axboe
2018-01-19 16:37 ` Ming Lei
2018-01-19 16:41 ` Jens Axboe
2018-01-19 16:41 ` Jens Axboe
2018-01-19 16:47 ` Mike Snitzer [this message]
2018-01-19 16:52 ` Jens Axboe
2018-01-19 17:05 ` Ming Lei
2018-01-19 17:09 ` Jens Axboe
2018-01-19 17:20 ` Ming Lei
2018-01-19 17:38 ` Jens Axboe
2018-01-19 18:24 ` Ming Lei
2018-01-19 18:24 ` Ming Lei
2018-01-19 18:33 ` Mike Snitzer
2018-01-19 23:52 ` Ming Lei
2018-01-20 4:27 ` Jens Axboe
2018-01-19 16:13 ` Mike Snitzer
2018-01-19 16:23 ` Jens Axboe
2018-01-19 23:57 ` Ming Lei
2018-01-29 22:37 ` Bart Van Assche
2018-01-19 5:09 ` Bart Van Assche
2018-01-19 5:09 ` Bart Van Assche
2018-01-19 7:34 ` Ming Lei
2018-01-19 19:47 ` Bart Van Assche
2018-01-19 19:47 ` Bart Van Assche
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