Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932833AbdHYNkN (ORCPT ); Fri, 25 Aug 2017 09:40:13 -0400 Received: from mail-it0-f53.google.com ([209.85.214.53]:38158 "EHLO mail-it0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932798AbdHYNkL (ORCPT ); Fri, 25 Aug 2017 09:40:11 -0400 MIME-Version: 1.0 In-Reply-To: <20170825101632.28065-4-brendan.jackman@arm.com> References: <20170825101632.28065-1-brendan.jackman@arm.com> <20170825101632.28065-4-brendan.jackman@arm.com> From: Vincent Guittot Date: Fri, 25 Aug 2017 15:39:50 +0200 Message-ID: Subject: Re: [PATCH v2 3/5] sched/fair: Fix find_idlest_group when local group is not allowed To: Brendan Jackman Cc: Ingo Molnar , Peter Zijlstra , linux-kernel , Joel Fernandes , Andres Oportus , Dietmar Eggemann , Josef Bacik , Morten Rasmussen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1760 Lines: 40 On 25 August 2017 at 12:16, Brendan Jackman wrote: > When the local group is not allowed we do not modify this_*_load from > their initial value of 0. That means that the load checks at the end > of find_idlest_group cause us to incorrectly return NULL. Fixing the > initial values to ULONG_MAX means we will instead return the idlest > remote group in that case. > > Signed-off-by: Brendan Jackman > Cc: Dietmar Eggemann > Cc: Vincent Guittot > Cc: Josef Bacik > Cc: Ingo Molnar > Cc: Morten Rasmussen > Cc: Peter Zijlstra Reviewed-by: Vincent Guittot > --- > kernel/sched/fair.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 4ccecbf825bf..0ce75bbcde45 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5387,8 +5387,9 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, > { > struct sched_group *idlest = NULL, *group = sd->groups; > struct sched_group *most_spare_sg = NULL; > - unsigned long min_runnable_load = ULONG_MAX, this_runnable_load = 0; > - unsigned long min_avg_load = ULONG_MAX, this_avg_load = 0; > + unsigned long min_runnable_load = ULONG_MAX; > + unsigned long this_runnable_load = ULONG_MAX; > + unsigned long min_avg_load = ULONG_MAX, this_avg_load = ULONG_MAX; > unsigned long most_spare = 0, this_spare = 0; > int load_idx = sd->forkexec_idx; > int imbalance_scale = 100 + (sd->imbalance_pct-100)/2; > -- > 2.14.1 >