From: Jens Axboe <axboe@suse.de>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>,
"Chen, Kenneth W" <kenneth.w.chen@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [patch] use cheaper elv_queue_empty when unplug a device
Date: Tue, 29 Mar 2005 12:19:47 +0200 [thread overview]
Message-ID: <20050329101947.GL16636@suse.de> (raw)
In-Reply-To: <1112091026.6282.43.camel@laptopd505.fenrus.org>
On Tue, Mar 29 2005, Arjan van de Ven wrote:
> On Tue, 2005-03-29 at 19:19 +1000, Nick Piggin wrote:
> > - removes the relock/retry merge mechanism in __make_request if we
> > aren't able to get the GFP_ATOMIC allocation. Just fall through
> > and assume the chances of getting a merge will be small (is this
> > a valid assumption? Should measure it I guess).
>
> this may have a potential problem; if the vm gets in trouble, you
> suddenly start to generate worse IO patterns, which means IO performance
> goes down right when it's most needed.....
>
> of course we need to figure if this actually ever hits in practice,
> because if it doesn't I'm all for simpler code.
Precisely, see my response as well. If the noretry flag works, that
should be fine.
--
Jens Axboe
next prev parent reply other threads:[~2005-03-29 10:20 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-29 2:53 [patch] use cheaper elv_queue_empty when unplug a device Chen, Kenneth W
2005-03-29 8:06 ` Jens Axboe
2005-03-29 9:19 ` Nick Piggin
2005-03-29 9:21 ` Nick Piggin
2005-03-29 9:28 ` Jens Axboe
2005-03-29 9:50 ` Nick Piggin
2005-03-29 10:06 ` Nick Piggin
2005-03-30 0:57 ` Nick Piggin
2005-03-30 8:11 ` Jens Axboe
2005-04-08 9:45 ` Jens Axboe
2005-04-08 9:55 ` Nick Piggin
2005-04-08 10:02 ` Jens Axboe
2005-04-08 10:22 ` Nick Piggin
2005-03-29 10:10 ` Arjan van de Ven
2005-03-29 10:19 ` Jens Axboe [this message]
2005-03-29 10:23 ` Nick Piggin
2005-03-29 13:15 ` Jens Axboe
2005-03-30 0:07 ` Nick Piggin
2005-03-29 19:02 ` Chen, Kenneth W
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