From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx185.postini.com [74.125.245.185]) by kanga.kvack.org (Postfix) with SMTP id 88E3D6B0068 for ; Fri, 29 Jun 2012 14:58:30 -0400 (EDT) Message-ID: <4FEDFAB1.8050305@redhat.com> Date: Fri, 29 Jun 2012 14:57:53 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 21/40] autonuma: avoid CFS select_task_rq_fair to return -1 References: <1340888180-15355-1-git-send-email-aarcange@redhat.com> <1340888180-15355-22-git-send-email-aarcange@redhat.com> In-Reply-To: <1340888180-15355-22-git-send-email-aarcange@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Hillf Danton , Dan Smith , Peter Zijlstra , Linus Torvalds , Andrew Morton , Thomas Gleixner , Ingo Molnar , Paul Turner , Suresh Siddha , Mike Galbraith , "Paul E. McKenney" , Lai Jiangshan , Bharata B Rao , Lee Schermerhorn , Johannes Weiner , Srivatsa Vaddagiri , Christoph Lameter , Alex Shi , Mauricio Faria de Oliveira , Konrad Rzeszutek Wilk , Don Morris , Benjamin Herrenschmidt On 06/28/2012 08:56 AM, Andrea Arcangeli wrote: > Fix to avoid -1 retval. > > Includes fixes from Hillf Danton. > > Signed-off-by: Andrea Arcangeli > --- > kernel/sched/fair.c | 4 ++++ > 1 files changed, 4 insertions(+), 0 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index c099cc6..fa96810 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2789,6 +2789,9 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) > if (new_cpu == -1 || new_cpu == cpu) { > /* Now try balancing at a lower domain level of cpu */ > sd = sd->child; > + if (new_cpu< 0) > + /* Return prev_cpu is find_idlest_cpu failed */ > + new_cpu = prev_cpu; > continue; > } > > @@ -2807,6 +2810,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) > unlock: > rcu_read_unlock(); > > + BUG_ON(new_cpu< 0); > return new_cpu; > } > #endif /* CONFIG_SMP */ Wait, what? Either this is a scheduler bugfix, in which case you are better off submitting it separately and reducing the size of your autonuma patch queue, or this is a behaviour change in the scheduler that needs better arguments than a 1-line changelog. -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org