From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758160Ab3EBLCy (ORCPT ); Thu, 2 May 2013 07:02:54 -0400 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:40697 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750878Ab3EBLCw (ORCPT ); Thu, 2 May 2013 07:02:52 -0400 Date: Thu, 2 May 2013 13:01:08 +0200 From: Peter Zijlstra To: Alex Shi Cc: mingo@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, morten.rasmussen@arm.com, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org, len.brown@intel.com, rafael.j.wysocki@intel.com, jkosina@suse.cz, clark.williams@gmail.com, tony.luck@intel.com, keescook@chromium.org, mgorman@suse.de, riel@redhat.com Subject: Re: [PATCH v4 2/6] sched: set initial value of runnable avg for new forked task Message-ID: <20130502110108.GA13494@dyad.programming.kicks-ass.net> References: <1367040344-14485-1-git-send-email-alex.shi@intel.com> <1367040344-14485-3-git-send-email-alex.shi@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1367040344-14485-3-git-send-email-alex.shi@intel.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 27, 2013 at 01:25:40PM +0800, Alex Shi wrote: > We need initialize the se.avg.{decay_count, load_avg_contrib} for a > new forked task. > Otherwise random values of above variables cause mess when do new task > enqueue: > enqueue_task_fair > enqueue_entity > enqueue_entity_load_avg > > and make forking balancing imbalance since incorrect load_avg_contrib. > > set avg.decay_count = 0, and avg.load_avg_contrib = se->load.weight to > resolve such issues. > > Signed-off-by: Alex Shi This patch seems sensible enough.. Acked-by: Peter Zijlstra > --- > kernel/sched/core.c | 6 ++++++ > kernel/sched/fair.c | 4 ++++ > 2 files changed, 10 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 86e87f1..e0c003a 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > + /* New forked task assumed with full utilization */ > +#if defined(CONFIG_SMP) > + p->se.avg.load_avg_contrib = p->se.load.weight; > +#endif We'd typically write: #ifdef CONFIG_SMP we only use the #if defined() form for multiple CONFIG tests.