Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755351Ab0LHOqP (ORCPT ); Wed, 8 Dec 2010 09:46:15 -0500 Received: from mx1.fusionio.com ([64.244.102.30]:39112 "EHLO mx1.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755285Ab0LHOqO (ORCPT ); Wed, 8 Dec 2010 09:46:14 -0500 X-ASG-Debug-ID: 1291819572-6da320170001-xx1T2L X-Barracuda-Envelope-From: JAxboe@fusionio.com Message-ID: <4CFF9A2C.1070401@fusionio.com> Date: Wed, 8 Dec 2010 22:46:04 +0800 From: Jens Axboe MIME-Version: 1.0 To: Satoru Takeuchi CC: Linus Torvalds , Yasuaki Ishimatsu , "vgoyal@redhat.com" , "jmarchan@redhat.com" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2] Don't merge different partition's IOs References: <4CFCB08F.4010509@jp.fujitsu.com> <4CFDDFC3.2070107@jp.fujitsu.com> <4CFF34E7.2030401@fusionio.com> <4CFF3AD6.6010904@jp.fujitsu.com> <4CFF3C86.2070504@fusionio.com> <4CFF3DA4.5060705@jp.fujitsu.com> X-ASG-Orig-Subj: Re: [PATCH 1/2] Don't merge different partition's IOs In-Reply-To: <4CFF3DA4.5060705@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Barracuda-Connect: mail1.int.fusionio.com[10.101.1.21] X-Barracuda-Start-Time: 1291819572 X-Barracuda-URL: http://10.101.1.180:8000/cgi-mod/mark.cgi X-Barracuda-Bayes: INNOCENT GLOBAL 0.4122 1.0000 0.0000 X-Barracuda-Spam-Score: 0.41 X-Barracuda-Spam-Status: No, SCORE=0.41 using global scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests=SUBJECT_FUZZY_TION X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.48835 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.41 SUBJECT_FUZZY_TION Attempt to obfuscate words in Subject: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1594 Lines: 44 On 2010-12-08 16:11, Satoru Takeuchi wrote: > Hi Jens, > > (2010/12/08 17:06), Jens Axboe wrote: >>>>> I hit on another approach. Although it doesn'tprevent any merge as Linus >>>>> preferred, it can fix the problem anyway. In this idea, in_flight is >>>>> incremented and decremented for the partition which the request belonged >>>>> to in its creation. It has the following merits. >>> >>> Revert is already finished. 2.6.37-rc-5 and latest stable kernel doesn't >>> contain Yasuaki's former logic. >>> >>> https://lkml.org/lkml/2010/10/24/118 >> >> Yes I know, that is why I said: >> >>>> I really would prefer if we fixed up the patchset we ended up reverting.. >>>> At least that had a purpose with growing struct request, since we saved >>>> on doing the partition lookups. >> >> That I prefer we fix that code up, since I think it's the best solution >> to the problem. >> > > I already postedit. > > https://lkml.org/lkml/2010/12/8/12 > > I think it is OK without mail subject :-) No, that's not it at all. What I mean (and what was reverted) was caching the partition lookup, and using that for the stats. The problem with that approach turned out to be the elevator queiscing logic not being fully correct. One easier way to fix that would be to reference count the part stats, instead of having to drain the queue. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/