From: Jens Axboe <axboe@kernel.dk>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Justin TerAvest <teravest@google.com>,
Chad Talbott <ctalbott@google.com>,
Nauman Rafique <nauman@google.com>,
Divyesh Shah <dpshah@google.com>,
lkml <linux-kernel@vger.kernel.org>,
Gui Jianfeng <guijianfeng@cn.fujitsu.com>,
Corrado Zoccolo <czoccolo@gmail.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Greg Thelen <gthelen@google.com>
Subject: Re: Per iocontext request descriptor limits (Was: Re: RFC: default group_isolation to 1, remove option)
Date: Fri, 04 Mar 2011 22:34:23 +0100 [thread overview]
Message-ID: <4D715ADF.10509@kernel.dk> (raw)
In-Reply-To: <20110304213147.GH5466@redhat.com>
On 2011-03-04 22:31, Vivek Goyal wrote:
> On Fri, Mar 04, 2011 at 12:01:41PM +0100, Jens Axboe wrote:
>> On 2011-03-03 19:03, Vivek Goyal wrote:
>>> On Thu, Mar 03, 2011 at 11:57:17AM -0500, Vivek Goyal wrote:
>>>
>>> [..]
>>>>> For now it's not a complicated effort, I already have a patch for this.
>>>>> If page tracking needs extra complexity, it'll have to remain in the
>>>>> page tracking code.
>>>>
>>>> Great. I am hoping once you get some free time, you will cleanup and post
>>>> that patch.
>>>
>>> Hmmm..., Now I got interested in this stuff. In case you would like to see
>>> your patch to be in and finding it hard to find time to clean it up, I can
>>> do that and repost and also fix any bugs.
>>
>> I did an initial run on the plane:
>>
>> http://git.kernel.dk/?p=linux-2.6-block.git;a=shortlog;h=refs/heads/for-2.6.39/ioc-rq-alloc
>>
>> Not tested at all, so there are likely a few bugs. Congestion is gone,
>> we'll need to consider that. Before the device was either congested or
>> not congested, now the question to ask would be "is the device congested
>> for ME" as the answer will depend on who is asking.
>
>
> Thanks Jens. I was having a quick look and noticed that ioc->count[] state
> is global across queues. I guess what we want is to keep track of ioc
> state per queue (something like cfq_io_context). By maintaining per device
> state in ioc, we can also tell whether a particular ioc is congested or
> not on a specific device.
Indeed, similar to how we setup cfq_io_contexts would be useful there...
Requires a bit of thinking.
I updated the patchset btw, found some silly errors in it. But yes, we
definitely need some better ->count[] tracking.
--
Jens Axboe
next prev parent reply other threads:[~2011-03-04 21:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-01 0:19 RFC: default group_isolation to 1, remove option Justin TerAvest
2011-03-01 14:20 ` Vivek Goyal
2011-03-01 18:44 ` Justin TerAvest
2011-03-02 21:28 ` Vivek Goyal
2011-03-06 16:06 ` Andrea Righi
2011-03-03 3:45 ` Jens Axboe
2011-03-03 15:30 ` Per iocontext request descriptor limits (Was: Re: RFC: default group_isolation to 1, remove option) Vivek Goyal
2011-03-03 15:44 ` Jens Axboe
2011-03-03 16:57 ` Vivek Goyal
2011-03-03 18:03 ` Vivek Goyal
2011-03-04 11:01 ` Jens Axboe
2011-03-04 21:31 ` Vivek Goyal
2011-03-04 21:34 ` Jens Axboe [this message]
2011-03-07 18:20 ` RFC: default group_isolation to 1, remove option Justin TerAvest
2011-03-07 19:39 ` Jens Axboe
2011-03-07 20:24 ` Vivek Goyal
2011-03-07 20:32 ` Jens Axboe
2011-03-07 20:46 ` Vivek Goyal
2011-03-07 20:47 ` Jens Axboe
2011-03-07 23:41 ` Justin TerAvest
2011-03-08 0:05 ` Vivek Goyal
2011-03-07 20:34 ` Vivek Goyal
2011-03-07 20:36 ` Jens Axboe
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