From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zefan Li Subject: Re: [PATCH v2] cpuset: Fix cpuset sched_relax_domain_level Date: Sat, 31 Jan 2015 08:31:09 +0800 Message-ID: <54CC224D.80201@huawei.com> References: <1422644094.3365.7.camel@j-VirtualBox> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1422644094.3365.7.camel@j-VirtualBox> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Jason Low Cc: Tejun Heo , Peter Zijlstra , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, aswin-VXdhtT5mjnY@public.gmane.org, scott.norton-VXdhtT5mjnY@public.gmane.org, chegu_vinod-VXdhtT5mjnY@public.gmane.org, stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On 2015/1/31 2:54, Jason Low wrote: > 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()") > Cc: # 3.9+ > Signed-off-by: Jason Low Acked-by: Zefan Li > --- > kernel/cpuset.c | 3 --- > 1 files changed, 0 insertions(+), 3 deletions(-) > > diff --git a/kernel/cpuset.c b/kernel/cpuset.c > index 64b257f..b589e57 100644 > --- a/kernel/cpuset.c > +++ b/kernel/cpuset.c > @@ -548,9 +548,6 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr, > > 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); >