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From: Bart Van Assche <Bart.VanAssche@wdc.com>
To: "snitzer@redhat.com" <snitzer@redhat.com>
Cc: "dm-devel@redhat.com" <dm-devel@redhat.com>,
	"hch@infradead.org" <hch@infradead.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	"axboe@fb.com" <axboe@fb.com>,
	"ming.lei@redhat.com" <ming.lei@redhat.com>,
	"loberman@redhat.com" <loberman@redhat.com>
Subject: Re: [PATCH 2/5] dm-mpath: return DM_MAPIO_REQUEUE in case of rq allocation failure
Date: Fri, 15 Sep 2017 20:48:56 +0000	[thread overview]
Message-ID: <1505508534.2417.9.camel@wdc.com> (raw)
In-Reply-To: <20170915200655.GA28136@redhat.com>

On Fri, 2017-09-15 at 16:06 -0400, Mike Snitzer wrote:
> The problem is that multipath_clone_and_map() is now treated as common
> code (thanks to both blk-mq and old .request_fn now enjoying the use of
> blk_get_request) BUT: Ming please understand that this code is used by
> old .request_fn too.  So it would seem that the use of
> DM_MAPIO_DELAY_REQUEUE vs DM_MAPIO_REQUEUE needs to be based on dm-sq vs
> dm-mq.

Hello Mike,

My proposal is to leave out patches 1 and 2 entirely. Since the SCSI core
calls blk_mq_run_hw_queues() anyway after a request has finished it is not
clear to me what the motivation was behind the development of patches 1 and
2 in this series. If the goal was to rerun a queue after a request has
finished I think the same approach should be taken for dm as for the SCSI
core, namely to run the queue from inside the end_io callback.

Bart.

  reply	other threads:[~2017-09-15 20:48 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-15 16:44 [PATCH 0/5] dm-mpath: improve I/O schedule Ming Lei
2017-09-15 16:44 ` [PATCH 1/5] block: don't call blk_mq_delay_run_hw_queue() in case of BLK_STS_RESOURCE Ming Lei
2017-09-15 17:57   ` Bart Van Assche
2017-09-17 12:40     ` Ming Lei
2017-09-18 15:18       ` Bart Van Assche
2017-09-19  5:43         ` Ming Lei
2017-09-19 15:36           ` Bart Van Assche
2017-09-19 15:56             ` Mike Snitzer
2017-09-19 16:04               ` Ming Lei
2017-09-19 16:49                 ` Bart Van Assche
2017-09-19 16:55                   ` Ming Lei
2017-09-19 18:42                     ` Bart Van Assche
2017-09-19 22:44                       ` Ming Lei
2017-09-19 23:25                         ` Bart Van Assche
2017-09-19 23:50                           ` Mike Snitzer
2017-09-20  1:13                             ` Ming Lei
2017-09-20  1:19                   ` Ming Lei
2017-09-19 15:48           ` Mike Snitzer
2017-09-19 15:52             ` Bart Van Assche
2017-09-19 16:03               ` Mike Snitzer
2017-09-19 16:07             ` Ming Lei
2017-09-15 16:44 ` [PATCH 2/5] dm-mpath: return DM_MAPIO_REQUEUE in case of rq allocation failure Ming Lei
2017-09-15 17:29   ` Bart Van Assche
2017-09-15 20:06     ` Mike Snitzer
2017-09-15 20:48       ` Bart Van Assche [this message]
2017-09-17 13:23       ` Ming Lei
2017-09-19 14:41         ` Mike Snitzer
2017-09-19 15:56           ` Ming Lei
2017-09-17 12:51     ` Ming Lei
2017-09-15 16:44 ` [PATCH 3/5] dm-mpath: remove annoying message of 'blk_get_request() returned -11' Ming Lei
2017-09-15 16:44 ` [PATCH 4/5] block: export blk_update_nr_requests Ming Lei
2017-09-15 16:44 ` [PATCH 5/5] dm-mpath: improve I/O schedule Ming Lei
2017-09-15 20:10   ` Mike Snitzer
2017-09-15 20:56   ` Bart Van Assche
2017-09-15 21:06   ` Bart Van Assche
2017-09-15 21:42   ` Bart Van Assche

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