From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756890AbcFAB6H (ORCPT ); Tue, 31 May 2016 21:58:07 -0400 Received: from mga04.intel.com ([192.55.52.120]:5570 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbcFAB6F (ORCPT ); Tue, 31 May 2016 21:58:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,398,1459839600"; d="scan'208";a="966230322" Date: Wed, 1 Jun 2016 02:00:30 +0800 From: Yuyang Du To: Peter Zijlstra Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, umgwanakikbuti@gmail.com, bsegall@google.com, pjt@google.com, morten.rasmussen@arm.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com Subject: Re: [RFC PATCH 1/2] sched: Clean up SD_BALANCE_WAKE flags in sched domain build-up Message-ID: <20160531180030.GS18670@intel.com> References: <1464657098-24880-1-git-send-email-yuyang.du@intel.com> <1464657098-24880-2-git-send-email-yuyang.du@intel.com> <20160531092146.GT3192@twins.programming.kicks-ass.net> <20160531013132.GQ18670@intel.com> <20160531104121.GJ3190@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160531104121.GJ3190@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 31, 2016 at 12:41:21PM +0200, Peter Zijlstra wrote: > On Tue, May 31, 2016 at 09:31:32AM +0800, Yuyang Du wrote: > > On Tue, May 31, 2016 at 11:21:46AM +0200, Peter Zijlstra wrote: > > > On Tue, May 31, 2016 at 09:11:37AM +0800, Yuyang Du wrote: > > > > The SD_BALANCE_WAKE is irrelevant in the contexts of these two removals, > > > > and in addition SD_BALANCE_WAKE is not and should not be set in any > > > > sched_domain flags so far. > > > > > > This Changelog doesn't make any sense... > > > > How? SD_BALANCE_WAKE is not in any sched_domain flags (sd->flags), even if > > it is, it is not used anywhere, no? > > It is and it is. See select_task_fair_rq(): > > if (tmp->flags & sd_flags) > > Now, as long as WAKE_AFFINE is also set, its hard to actually get into > the find_idlest_cpu() balancing, but if you clear all that you will > still get there. Well, that is very true, and the next patch (2/2) just makes all this what this is supposed to be: the SD_BALANCE_WAKE is a meaningful sched_domain flag. This particular patch is a pure cleanup, may I amend the changelog to: According to the comment: "turn off/on idle balance on this domain", the SD_BALANCE_WAKE has nothing to do with idle balance, so clean them up.