Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758499AbbLCEp1 (ORCPT ); Wed, 2 Dec 2015 23:45:27 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52205 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758174AbbLCEp0 (ORCPT ); Wed, 2 Dec 2015 23:45:26 -0500 From: Xunlei Pang To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Steven Rostedt , Xunlei Pang Subject: [PATCH v2 1/3] sched/core: Clear the root_domain cpumasks in init_rootdomain() Date: Thu, 3 Dec 2015 12:44:59 +0800 Message-Id: <1449117901-9561-1-git-send-email-xlpang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2081 Lines: 55 root_domain::rto_mask allocated through alloc_cpumask_var() contains garbage data with CONFIG_CPUMASK_OFFSTACK set, this may cause problems. For instance, When doing pull_rt_task(), it may do useless iterations if rto_mask retains some extra garbage bits. Worse still, this can violate the isolated domain rule for clustered scheduling using cpuset, because the tasks (with all the cpus allowed) which belongs to one root domain can be pulled away into another root domain. The patch cleans the garbage by passing alloc_cpumask_var() with an extra __GFP_ZERO for root_domain::rto_mask allocation, thereby addressing the issues. Do the same thing for root_domain's other cpumask memembers: dlo_mask, span, and online. Signed-off-by: Xunlei Pang --- v1->v2: Use alloc_cpumask_var() with __GFP_ZERO instead of zalloc_cpumask_var() to avoid duplicate clean for systems without CONFIG_CPUMASK_OFFSTACK set. kernel/sched/core.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5b420d2..c11e11e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5858,13 +5858,13 @@ static int init_rootdomain(struct root_domain *rd) { memset(rd, 0, sizeof(*rd)); - if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) + if (!alloc_cpumask_var(&rd->span, GFP_KERNEL | __GFP_ZERO)) goto out; - if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) + if (!alloc_cpumask_var(&rd->online, GFP_KERNEL | __GFP_ZERO)) goto free_span; - if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) + if (!alloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL | __GFP_ZERO)) goto free_online; - if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) + if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL | __GFP_ZERO)) goto free_dlo_mask; init_dl_bw(&rd->dl_bw); -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/