Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752033Ab2BQLjy (ORCPT ); Fri, 17 Feb 2012 06:39:54 -0500 Received: from mail-vx0-f174.google.com ([209.85.220.174]:39794 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751097Ab2BQLjw convert rfc822-to-8bit (ORCPT ); Fri, 17 Feb 2012 06:39:52 -0500 MIME-Version: 1.0 In-Reply-To: <1329408142.2293.241.camel@twins> References: <20120202013825.20844.26081.stgit@kitami.mtv.corp.google.com> <20120202013826.20844.47587.stgit@kitami.mtv.corp.google.com> <1329408142.2293.241.camel@twins> From: Paul Turner Date: Fri, 17 Feb 2012 03:39:22 -0800 Message-ID: Subject: Re: [RFC PATCH 05/14] sched: account for blocked load waking back up To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Venki Pallipadi , Srivatsa Vaddagiri , Mike Galbraith , Kamalesh Babulal , Ben Segall , Ingo Molnar , Vaidyanathan Srinivasan Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1070 Lines: 29 On Thu, Feb 16, 2012 at 8:02 AM, Peter Zijlstra wrote: > On Wed, 2012-02-01 at 17:38 -0800, Paul Turner wrote: > >> ? ? ? ? u64 last_runnable_update, decay_count; > >> + ? ? ? /* we track migrations using entity decay_count == 0 */ >> + ? ? ? if (unlikely(se->avg.decay_count <= 0)) { > > !sleep dequeue isn't migrate only, Well they mostly are these days; but in the == 0 case we're either a load-balancer migration or someone doing a dequeue/enqueue pair on an entity about some sort of update. The key is that when it is an load-balancer move we'll resync appropriately on enqueue (which we need to do). We will essentially sync with ourselves in the other cases, but they have no bearing on why we do this. > also, <= 0 on an unsigned is weird. Yeah that should be a s64 not u64 (fixed). > -- 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/