Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757130AbZCCKmm (ORCPT ); Tue, 3 Mar 2009 05:42:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754106AbZCCKmd (ORCPT ); Tue, 3 Mar 2009 05:42:33 -0500 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:54468 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754054AbZCCKmc (ORCPT ); Tue, 3 Mar 2009 05:42:32 -0500 Message-ID: <2d4a44772433903887651c0bfe74c9cc.squirrel@webmail-b.css.fujitsu.com> In-Reply-To: <1236073236.18955.46.camel@twins> References: <49A65455.4030204@cn.fujitsu.com> <20090226174033.094e4834.kamezawa.hiroyu@jp.fujitsu.com> <344eb09a0902260210y44c0684by9b22f041116d3f7c@mail.gmail.com> <18f6db017e5d44596e828e0753f28e75.squirrel@webmail-b.css.fujitsu.com> <1235645076.4645.4781.camel@laptop> <934198669efa83e838a52284e2c4f8b5.squirrel@webmail-b.css.fujitsu.com> <1235647682.4948.15.camel@laptop> <145d0010d65060bb089d5a87e06cbd0d.squirrel@webmail-b.css.fujitsu.com> <20090226164509.GB6634@linux.vnet.ibm.com> <20090227095856.ef8c1c05.kamezawa.hiroyu@jp.fujitsu.com> <20090227012915.GF6634@linux.vnet.ibm.com> <20090227122239.875a3f56.kamezawa.hiroyu@jp.fujitsu.com> <1236005770.5330.583.camel@laptop> <20090303084218.28010267.kamezawa.hiroyu@jp.fujitsu.com> <1236066689.18955.27.camel@twins> <1236073236.18955.46.camel@twins> Date: Tue, 3 Mar 2009 19:42:24 +0900 (JST) Subject: Re: [RFC][PATCH] remove rq->lock from cpuacct cgroup (Was Re: [PATCH] cpuacct: add a branch prediction From: "KAMEZAWA Hiroyuki" To: "Peter Zijlstra" Cc: "KAMEZAWA Hiroyuki" , paulmck@linux.vnet.ibm.com, "Bharata B Rao" , "Li Zefan" , "Ingo Molnar" , "Paul Menage" , "Balbir Singh" , "LKML" User-Agent: SquirrelMail/1.4.16 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-2022-jp Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1036 Lines: 32 Peter Zijlstra wrote: > On Tue, 2009-03-03 at 18:04 +0900, KAMEZAWA Hiroyuki wrote: >> Peter Zijlstra wrote: >> > On Tue, 2009-03-03 at 08:42 +0900, KAMEZAWA Hiroyuki wrote: >> > >> >> > Furthermore, if you want something like schedule_work_on() for each >> >> cpu, >> >> > there's schedule_on_each_cpu(). >> >> > >> >> It can't pass arguments...Maybe I should use rq->lock here to reset >> >> other cpu's value. >> > >> > Why bother with serializing the reset code at all? >> > >> I don't think reset v.s. read is problem but reset v.s. increment >> (read-modify-write) can't be ? > > Sure, can be, do we care? > If small/easy code allows us to declare "there are any racy case! and you don't have to check whether you successfully reseted", it's worth to do I think. Thanks, -Kame -- 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/