From: Jens Axboe <jens.axboe@oracle.com>
To: Arjan van de Ven <arjan@fenrus.demon.nl>
Cc: Dan Aloni <da-x@monatomic.org>,
Linux Kernel List <linux-kernel@vger.kernel.org>,
linux-scsi@vger.kernel.org, Mike Christie <michaelc@cs.wisc.edu>
Subject: Re: [PATCH] scsi_execute_async() should add to the tail of the queue
Date: Tue, 19 Dec 2006 12:26:49 +0100 [thread overview]
Message-ID: <20061219112649.GG5010@kernel.dk> (raw)
In-Reply-To: <1166522613.3365.1198.camel@laptopd505.fenrus.org>
On Tue, Dec 19 2006, Arjan van de Ven wrote:
> On Tue, 2006-12-19 at 10:35 +0200, Dan Aloni wrote:
> > Hello,
> >
> > scsi_execute_async() has replaced scsi_do_req() a few versions ago,
> > but it also incurred a change of behavior. I noticed that over-queuing
> > a SCSI device using that function causes I/Os to be starved from
> > low-level queuing for no justified reason.
> >
> > I think it makes much more sense to perserve the original behaviour
> > of scsi_do_req() and add the request to the tail of the queue.
>
> Hi,
>
> some things should really be added to the head of the queue, like
> maintenance requests and error handling requests. Are you sure this is
> the right change? At least I'd expect 2 apis, one for a head and one for
> a "normal" queueing...
It does sounds broken - head insertion should only be used for careful
internal commands, not be the default way user issued commands. Looking
at the current users, the patch makes sense to me.
--
Jens Axboe
next prev parent reply other threads:[~2006-12-19 11:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-19 8:35 [PATCH] scsi_execute_async() should add to the tail of the queue Dan Aloni
2006-12-19 10:03 ` Arjan van de Ven
2006-12-19 10:34 ` Dan Aloni
2006-12-20 23:50 ` Jeremy Linton
2006-12-19 11:26 ` Jens Axboe [this message]
2006-12-19 18:34 ` Jon Escombe
2006-12-19 18:44 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2006-12-19 0:02 Dan Aloni
2006-12-20 20:40 ` Steven Hayter
2006-12-21 7:12 ` Dan Aloni
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