From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752633AbeCPOgD (ORCPT ); Fri, 16 Mar 2018 10:36:03 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:55904 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751445AbeCPOgC (ORCPT ); Fri, 16 Mar 2018 10:36:02 -0400 Date: Fri, 16 Mar 2018 15:35:50 +0100 From: Peter Zijlstra To: Rohit Jain Cc: linux-kernel@vger.kernel.org, mingo@redhat.com, steven.sistare@oracle.com, joelaf@google.com, jbacik@fb.com, juri.lelli@redhat.com, dhaval.giani@oracle.com, efault@gmx.de, riel@surriel.com Subject: Re: [RESEND PATCH v2] sched/fair: Remove check in idle_balance against migration_cost Message-ID: <20180316143550.GH4064@hirez.programming.kicks-ass.net> References: <1521052607-24622-1-git-send-email-rohit.k.jain@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1521052607-24622-1-git-send-email-rohit.k.jain@oracle.com> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 14, 2018 at 11:36:47AM -0700, Rohit Jain wrote: > Signed-off-by: Rohit Jain > > Signed-off-by: Rohit Jain Surely you only need a single on of those. > --- > kernel/sched/fair.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 5eb3ffc..569ea83 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -8804,8 +8804,7 @@ static int idle_balance(struct rq *this_rq, struct rq_flags *rf) > */ > rq_unpin_lock(this_rq, rf); > > - if (this_rq->avg_idle < sysctl_sched_migration_cost || > - !this_rq->rd->overload) { > + if (!this_rq->rd->overload) { > rcu_read_lock(); > sd = rcu_dereference_check_sched_domain(this_rq->sd); > if (sd) I don't think that actually works right on the current tree. In particular look at commit: 31e77c93e432 ("sched/fair: Update blocked load when newly idle")