From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754655Ab1EJHXI (ORCPT ); Tue, 10 May 2011 03:23:08 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:49895 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752181Ab1EJHXG (ORCPT ); Tue, 10 May 2011 03:23:06 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4DC8E7C2.5080402@jp.fujitsu.com> Date: Tue, 10 May 2011 16:22:42 +0900 From: Hidetoshi Seto User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; ja; rv:1.9.2.17) Gecko/20110414 Thunderbird/3.1.10 MIME-Version: 1.0 To: Paul Turner CC: linux-kernel@vger.kernel.org, Peter Zijlstra , Bharata B Rao , Dhaval Giani , Balbir Singh , Vaidyanathan Srinivasan , Srivatsa Vaddagiri , Kamalesh Babulal , Ingo Molnar , Pavel Emelyanov Subject: Re: [patch 07/15] sched: expire invalid runtime References: <20110503092846.022272244@google.com> <20110503092905.075386331@google.com> In-Reply-To: <20110503092905.075386331@google.com> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2011/05/03 18:28), Paul Turner wrote: > With the global quota pool, one challenge is determining when the runtime we > have received from it is still valid. Fortunately we can take advantage of > sched_clock synchronization around the jiffy to do this cheaply. > > The one catch is that we don't know whether our local clock is behind or ahead > of the cpu setting the expiration time (relative to its own clock). > > Fortunately we can detect which of these is the case by determining whether the > global deadline has advanced. If it has not, then we assume we are behind, and > advance our local expiration; otherwise, we know the deadline has truly passed > and we expire our local runtime. > > Signed-off-by: Paul Turner > > --- Reviewed-by: Hidetoshi Seto Thanks, H.Seto