From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from outbound-smtp09.blacknight.com ([46.22.139.14]:34857 "EHLO outbound-smtp09.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936434AbdGTVVq (ORCPT ); Thu, 20 Jul 2017 17:21:46 -0400 Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp09.blacknight.com (Postfix) with ESMTPS id 245471C2022 for ; Thu, 20 Jul 2017 22:21:45 +0100 (IST) From: Mel Gorman To: Linux-Stable Cc: Mel Gorman Subject: [PATCH 02/26] sched/topology: Fix building of overlapping sched-groups Date: Thu, 20 Jul 2017 22:21:20 +0100 Message-Id: <20170720212144.18453-3-mgorman@techsingularity.net> In-Reply-To: <20170720212144.18453-1-mgorman@techsingularity.net> References: <20170720212144.18453-1-mgorman@techsingularity.net> Sender: stable-owner@vger.kernel.org List-ID: From: Peter Zijlstra commit 0372dd2736e02672ac6e189c31f7d8c02ad543cd upstream. When building the overlapping groups, we very obviously should start with the previous domain of _this_ @cpu, not CPU-0. This can be readily demonstrated with a topology like: node 0 1 2 3 0: 10 20 30 20 1: 20 10 20 30 2: 30 20 10 20 3: 20 30 20 10 Where (for example) CPU1 ends up generating the following nonsensical groups: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 2 0 [] domain 1: span 0-3 level NUMA [] groups: 1-3 (cpu_capacity = 3072) 0-1,3 (cpu_capacity = 3072) Where the fact that domain 1 doesn't include a group with span 0-2 is the obvious fail. With patch this looks like: [] CPU1 attaching sched-domain: [] domain 0: span 0-2 level NUMA [] groups: 1 0 2 [] domain 1: span 0-3 level NUMA [] groups: 0-2 (cpu_capacity = 3072) 0,2-3 (cpu_capacity = 3072) Debugged-by: Lauro Ramos Venancio Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org Fixes: e3589f6c81e4 ("sched: Allow for overlapping sched_domain spans") Signed-off-by: Ingo Molnar Signed-off-by: Mel Gorman --- kernel/sched/topology.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index d786d45c44d9..921dedde2ee1 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -566,7 +566,7 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) cpumask_clear(covered); - for_each_cpu(i, span) { + for_each_cpu_wrap(i, span, cpu) { struct cpumask *sg_span; if (cpumask_test_cpu(i, covered)) -- 2.13.1