From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753882AbYKFBsT (ORCPT ); Wed, 5 Nov 2008 20:48:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752407AbYKFBsL (ORCPT ); Wed, 5 Nov 2008 20:48:11 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:49777 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752299AbYKFBsK (ORCPT ); Wed, 5 Nov 2008 20:48:10 -0500 Message-ID: <49124C2C.9080300@cn.fujitsu.com> Date: Thu, 06 Nov 2008 09:45:16 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Ingo Molnar CC: Peter Zijlstra , LKML , suresh.b.siddha@intel.com Subject: [PATCH] sched: fix a bug in sched domain degenerate Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (1) on i386 with SCHED_SMT and SCHED_MC enabled # mount -t cgroup -o cpuset xxx /mnt # echo 0 > /mnt/cpuset.sched_load_balance # mkdir /mnt/0 # echo 0 > /mnt/0/cpuset.cpus # dmesg CPU0 attaching sched-domain: domain 0: span 0 level CPU groups: 0 (2) on i386 with SCHED_MC enabled but SCHED_SMT disabled # same with (1) # dmesg CPU0 attaching NULL sched-domain. The bug is some sched domains may be skipped unintentionally when doing sched domain degenerating. Signed-off-by: Li Zefan --- kernel/sched.c | 6 ++++-- 1 files changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index dee79ad..b13f45a 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -6875,15 +6875,17 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) struct sched_domain *tmp; /* Remove the sched domains which do not contribute to scheduling. */ - for (tmp = sd; tmp; tmp = tmp->parent) { + for (tmp = sd; tmp; ) { struct sched_domain *parent = tmp->parent; if (!parent) break; + if (sd_parent_degenerate(tmp, parent)) { tmp->parent = parent->parent; if (parent->parent) parent->parent->child = tmp; - } + } else + tmp = tmp->parent; } if (sd && sd_degenerate(sd)) { -- 1.5.4.rc3