From: Jens Axboe <axboe@suse.de>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Tejun Heo <htejun@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
SCSI Mailing List <linux-scsi@vger.kernel.org>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH scsi-misc-2.6 03/05] scsi: make scsi_queue_insert() use blk_requeue_request()
Date: Fri, 22 Apr 2005 13:37:50 +0200 [thread overview]
Message-ID: <20050422113749.GZ9371@suse.de> (raw)
In-Reply-To: <1114087528.5054.2.camel@mulgrave>
On Thu, Apr 21 2005, James Bottomley wrote:
> On Thu, 2005-04-21 at 08:10 +0200, Jens Axboe wrote:
> > I wondered about this action recently myself. What is the point in
> > requeueing this request, only to call scsi_run_queue() ->
> > blk_run_queue() -> issue same request. If the point really is to reissue
> > the request immediately, I can think of many ways more efficient than
> > this :-)
>
> Well ... that's because the logic that decides whether to plug the queue
> or simply exit is in the scsi_request_fn(). That's what the comment is
> about. We could abstract the check into a function, but (unless you
> have any suggestions on rewording it) I thought the comment made what
> was going on reasonably clear.
>
Looks fine, I just missed enough code context in the patch to see this.
Since requeuing probably isn't all that uncommon, it may make sense to
optimize this a little though.
--
Jens Axboe
next prev parent reply other threads:[~2005-04-22 11:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-19 23:15 [PATCH scsi-misc-2.6 00/05] scsi: change REQ_SPECIAL/REQ_SOFTBARRIER usages Tejun Heo
2005-04-19 23:15 ` [PATCH scsi-misc-2.6 01/05] scsi: make blk layer set REQ_SOFTBARRIER when a request is dispatched Tejun Heo
2005-04-20 6:30 ` Jens Axboe
2005-04-20 6:44 ` Tejun Heo
2005-04-20 7:40 ` Tejun Heo
2005-04-20 7:58 ` Nick Piggin
2005-04-20 8:37 ` Tejun Heo
2005-04-20 8:38 ` Jens Axboe
2005-04-20 9:04 ` Nick Piggin
2005-04-20 9:14 ` Jens Axboe
2005-04-20 9:24 ` Nick Piggin
2005-04-20 9:44 ` Jens Axboe
2005-04-20 22:58 ` Tejun Heo
2005-04-19 23:15 ` [PATCH scsi-misc-2.6 02/05] scsi: remove REQ_SPECIAL in scsi_init_io() Tejun Heo
2005-04-19 23:15 ` [PATCH scsi-misc-2.6 03/05] scsi: make scsi_queue_insert() use blk_requeue_request() Tejun Heo
2005-04-20 23:24 ` James Bottomley
2005-04-21 0:20 ` Tejun Heo
2005-04-21 2:16 ` James Bottomley
2005-04-21 2:29 ` Tejun Heo
2005-04-21 2:43 ` Tejun Heo
2005-04-21 6:10 ` Jens Axboe
2005-04-21 12:45 ` James Bottomley
2005-04-22 11:37 ` Jens Axboe [this message]
2005-04-19 23:15 ` [PATCH scsi-misc-2.6 04/05] scsi: make scsi_requeue_request() " Tejun Heo
2005-04-19 23:16 ` [PATCH scsi-misc-2.6 05/05] scsi: remove requeue feature from blk_insert_request() Tejun Heo
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