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 11:34:38 +0800 [thread overview]
Message-ID: <1325820878.22361.518.camel@sli10-conroe> (raw)
In-Reply-To: <20120106030406.GD6276@google.com>
On Thu, 2012-01-05 at 19:04 -0800, Tejun Heo wrote:
> Hello,
>
> On Fri, Jan 06, 2012 at 11:14:15AM +0800, Shaohua Li wrote:
> > > So, yeah, the right fix would be using elv_former/latter_request()
> > > instead. Maybe we should strip out rqhash altogether and change
> > > elevator handle everything? I don't know. I'll prepare a different
> > > fix patch soon.
> >
> > So not allow merge from two cfq queues strictly? This will impact
> > performance. I don't know how important the strict isolation is. we even
> > allow two cfq queues merge to improve performance.
>
> 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.
Thanks,
Shaohua
next prev parent reply other threads:[~2012-01-06 3:19 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111221174733.9ba0861e762e8d96844b060b@canb.auug.org.au>
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 ` Shaohua Li [this message]
2012-01-06 3:22 ` [PATCH block:for-3.3/core] cfq: merged request shouldn't jump to a different cfqq Tejun Heo
2012-01-06 4:15 ` Shaohua Li
2012-01-06 4:40 ` Tejun Heo
2012-01-06 2:47 ` Shaohua Li
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