Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Low , Zefan Li , Tejun Heo , Serge Hallyn Subject: [PATCH 3.19 056/123] cpuset: Fix cpuset sched_relax_domain_level Date: Tue, 24 Mar 2015 16:46:05 +0100 Message-Id: <20150324154426.617717222@linuxfoundation.org> In-Reply-To: <20150324154423.655554012@linuxfoundation.org> References: <20150324154423.655554012@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Low commit 283cb41f426b723a0255702b761b0fc5d1b53a81 upstream. The cpuset.sched_relax_domain_level can control how far we do immediate load balancing on a system. However, it was found on recent kernels that echo'ing a value into cpuset.sched_relax_domain_level did not reduce any immediate load balancing. The reason this occurred was because the update_domain_attr_tree() traversal did not update for the "top_cpuset". This resulted in nothing being changed when modifying the sched_relax_domain_level parameter. This patch is able to address that problem by having update_domain_attr_tree() allow updates for the root in the cpuset traversal. Fixes: fc560a26acce ("cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()") Signed-off-by: Jason Low Signed-off-by: Zefan Li Signed-off-by: Tejun Heo Tested-by: Serge Hallyn Signed-off-by: Greg Kroah-Hartman --- kernel/cpuset.c | 3 --- 1 file changed, 3 deletions(-) --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -548,9 +548,6 @@ static void update_domain_attr_tree(stru rcu_read_lock(); cpuset_for_each_descendant_pre(cp, pos_css, root_cs) { - if (cp == root_cs) - continue; - /* skip the whole subtree if @cp doesn't have any CPU */ if (cpumask_empty(cp->cpus_allowed)) { pos_css = css_rightmost_descendant(pos_css);