From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751704AbdHBBJX (ORCPT ); Tue, 1 Aug 2017 21:09:23 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:10816 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbdHBBJW (ORCPT ); Tue, 1 Aug 2017 21:09:22 -0400 Subject: Re: [PATCH 3/3] cpuset: make nr_cpusets private To: Paolo Bonzini , References: <1501601046-35683-1-git-send-email-pbonzini@redhat.com> <1501601046-35683-4-git-send-email-pbonzini@redhat.com> CC: Peter Zijlstra From: Zefan Li Message-ID: <598125FA.1080900@huawei.com> Date: Wed, 2 Aug 2017 09:08:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1501601046-35683-4-git-send-email-pbonzini@redhat.com> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.19.236] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.59812619.005F,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 750839c726d803539b80c04dc143824c Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/8/1 23:24, Paolo Bonzini wrote: > Any use of key->enabled (that is static_key_enabled and static_key_count) > outside jump_label_lock should handle its own serialization. In the case > of cpusets_enabled_key, the key is always incremented/decremented under > cpuset_mutex, and hence the same rule applies to nr_cpusets. The rule > *is* respected currently, but the mutex is static so nr_cpusets should > be static too. > > Cc: Peter Zijlstra > Cc: Zefan Li > Signed-off-by: Paolo Bonzini Acked-by: Zefan Li > --- > include/linux/cpuset.h | 6 ------ > kernel/cgroup/cpuset.c | 7 +++++++ > 2 files changed, 7 insertions(+), 6 deletions(-) > > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h > index 119a3f9604b0..cedcc910b7a7 100644 > --- a/include/linux/cpuset.h > +++ b/include/linux/cpuset.h > @@ -24,12 +24,6 @@ static inline bool cpusets_enabled(void) > return static_branch_unlikely(&cpusets_enabled_key); > } > > -static inline int nr_cpusets(void) > -{ > - /* jump label reference count + the top-level cpuset */ > - return static_key_count(&cpusets_enabled_key.key) + 1; > -} > - > static inline void cpuset_inc(void) > { > static_branch_inc(&cpusets_enabled_key); > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index ae643412948a..f65db17e9e23 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -576,6 +576,13 @@ static void update_domain_attr_tree(struct sched_domain_attr *dattr, > rcu_read_unlock(); > } > > +/* Must be called with cpuset_mutex held. */ > +static inline int nr_cpusets(void) > +{ > + /* jump label reference count + the top-level cpuset */ > + return static_key_count(&cpusets_enabled_key.key) + 1; > +} > + > /* > * generate_sched_domains() > * >