From: Shaohua Li <shaohua.li@intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>, Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-next@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org,
x86@kernel.org
Subject: Re: [PATCH block:for-3.3/core] cfq: merged request shouldn't jump to a different cfqq
Date: Fri, 06 Jan 2012 12:15:49 +0800 [thread overview]
Message-ID: <1325823349.22361.523.camel@sli10-conroe> (raw)
In-Reply-To: <CAOS58YOcciTFzYU9vsW2pnE=dbNo+rGz2XJ0Qjk4VHriNDw31g@mail.gmail.com>
On Thu, 2012-01-05 at 19:22 -0800, Tejun Heo wrote:
> On Thu, Jan 5, 2012 at 7:34 PM, Shaohua Li <shaohua.li@intel.com> wrote:
> >> That's how cfq has behaved before this recent plug merge breakage and
> >> IIRC why the cooperating queue thing is there. If you want to change
> >> the behavior, that should be an explicit separate patch.
> > My point is both cooperating merge and the plug merge of different cfq
> > are merge, no reason we allow one but disallow the other. plug merge
> > isn't a breakage to me.
>
> Isolation is pretty big deal for cfq and cross cfqq merging happening
> without cfq noticing it isn't gonna be helpful to the cause. Why
> don't we merge bio's across different cfqq's then?
don't know. I don't think a tweak for merge impacts isolation so much.
For rotate disk, request size hasn't impact to request cost, so this
doesn't impact isolation. Even for ssd, big size request is more
efficient to dispatch. And we already have breakage of fairness for SSD,
such as no idle.
next prev parent reply other threads:[~2012-01-06 4:01 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-21 6:47 linux-next: Tree for Dec 21 Stephen Rothwell
2011-12-21 20:11 ` linux-next: Tree for Dec 21 (xen) Randy Dunlap
2011-12-21 19:30 ` Konrad Rzeszutek Wilk
2011-12-21 20:32 ` [PATCH] usb: fix renesas mod_gadget printk format warning Randy Dunlap
2011-12-21 21:16 ` Felipe Balbi
2011-12-21 22:19 ` Randy Dunlap
2011-12-21 21:24 ` Greg KH
2011-12-21 23:15 ` linux-next: Tree for Dec 21 Andrew Morton
2011-12-22 23:08 ` Andrew Morton
2011-12-22 23:20 ` Tejun Heo
2011-12-22 23:24 ` Andrew Morton
2011-12-22 23:38 ` Tejun Heo
2011-12-22 23:44 ` Andrew Morton
2011-12-22 23:46 ` Tejun Heo
2011-12-23 0:42 ` Tejun Heo
2011-12-24 5:13 ` Hugh Dickins
2011-12-25 1:02 ` [PATCH block/for-3.3/core] block: an exiting task should be allowed to create io_context Tejun Heo
2011-12-25 13:29 ` Jens Axboe
2011-12-27 22:07 ` Andrew Morton
2011-12-28 8:33 ` Hugh Dickins
2011-12-28 16:48 ` Tejun Heo
2011-12-28 17:50 ` Hugh Dickins
2011-12-28 17:55 ` Tejun Heo
2011-12-28 21:19 ` Tejun Heo
2012-01-03 17:35 ` Tejun Heo
2012-01-03 17:59 ` Tejun Heo
2012-01-03 20:09 ` Tejun Heo
2012-01-03 20:20 ` Jens Axboe
2012-01-03 22:13 ` Tejun Heo
2012-01-03 22:35 ` Tejun Heo
2012-01-05 1:24 ` Tejun Heo
2012-01-05 18:36 ` Hugh Dickins
2012-01-05 18:38 ` Tejun Heo
2012-01-06 2:17 ` [PATCH block:for-3.3/core] cfq: merged request shouldn't jump to a different cfqq Tejun Heo
2012-01-06 2:36 ` Tejun Heo
2012-01-06 3:14 ` Shaohua Li
2012-01-06 3:04 ` Tejun Heo
2012-01-06 3:30 ` Tejun Heo
2012-01-06 3:52 ` [PATCH block:for-3.3/core] block: disable ELEVATOR_INSERT_SORT_MERGE Tejun Heo
2012-01-06 4:19 ` Shaohua Li
2012-01-06 4:38 ` Tejun Heo
2012-01-06 8:15 ` Shaohua Li
2012-01-06 15:34 ` Tejun Heo
2012-01-06 3:34 ` [PATCH block:for-3.3/core] cfq: merged request shouldn't jump to a different cfqq Shaohua Li
2012-01-06 3:22 ` Tejun Heo
2012-01-06 4:15 ` Shaohua Li [this message]
2012-01-06 4:40 ` Tejun Heo
2012-01-06 2:47 ` Shaohua Li
2011-12-25 16:08 ` linux-next: Tree for Dec 21 Sedat Dilek
2011-12-25 23:55 ` Stephen Rothwell
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