From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755814AbaJ1LGb (ORCPT ); Tue, 28 Oct 2014 07:06:31 -0400 Received: from terminus.zytor.com ([198.137.202.10]:51040 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755777AbaJ1LGZ (ORCPT ); Tue, 28 Oct 2014 07:06:25 -0400 Date: Tue, 28 Oct 2014 04:05:29 -0700 From: tip-bot for Rik van Riel Message-ID: Cc: torvalds@linux-foundation.org, peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, riel@redhat.com, chegu_vinod@hp.com, hpa@zytor.com Reply-To: linux-kernel@vger.kernel.org, riel@redhat.com, hpa@zytor.com, chegu_vinod@hp.com, torvalds@linux-foundation.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de In-Reply-To: <20141009172747.0d97c38c@annuminas.surriel.com> References: <20141009172747.0d97c38c@annuminas.surriel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/numa: Check all nodes when placing a pseudo-interleaved group Git-Commit-ID: 9de05d48711cd5314920ed05f873d84eaf66ccf1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 9de05d48711cd5314920ed05f873d84eaf66ccf1 Gitweb: http://git.kernel.org/tip/9de05d48711cd5314920ed05f873d84eaf66ccf1 Author: Rik van Riel AuthorDate: Thu, 9 Oct 2014 17:27:47 -0400 Committer: Ingo Molnar CommitDate: Tue, 28 Oct 2014 10:47:52 +0100 sched/numa: Check all nodes when placing a pseudo-interleaved group In pseudo-interleaved numa_groups, all tasks try to relocate to the group's preferred_nid. When a group is spread across multiple NUMA nodes, this can lead to tasks swapping their location with other tasks inside the same group, instead of swapping location with tasks from other NUMA groups. This can keep NUMA groups from converging. Examining all nodes, when dealing with a task in a pseudo-interleaved NUMA group, avoids this problem. Note that only CPUs in nodes that improve the task or group score are examined, so the loop isn't too bad. Tested-by: Vinod Chegu Signed-off-by: Rik van Riel Signed-off-by: Peter Zijlstra (Intel) Cc: "Vinod Chegu" Cc: mgorman@suse.de Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20141009172747.0d97c38c@annuminas.surriel.com Signed-off-by: Ingo Molnar --- kernel/sched/fair.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7760c2a..ec32c26d 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1436,8 +1436,15 @@ static int task_numa_migrate(struct task_struct *p) /* Try to find a spot on the preferred nid. */ task_numa_find_cpu(&env, taskimp, groupimp); - /* No space available on the preferred nid. Look elsewhere. */ - if (env.best_cpu == -1) { + /* + * Look at other nodes in these cases: + * - there is no space available on the preferred_nid + * - the task is part of a numa_group that is interleaved across + * multiple NUMA nodes; in order to better consolidate the group, + * we need to check other locations. + */ + if (env.best_cpu == -1 || (p->numa_group && + nodes_weight(p->numa_group->active_nodes) > 1)) { for_each_online_node(nid) { if (nid == env.src_nid || nid == p->numa_preferred_nid) continue;