From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754225Ab2KGPaZ (ORCPT ); Wed, 7 Nov 2012 10:30:25 -0500 Received: from cantor2.suse.de ([195.135.220.15]:43424 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753075Ab2KGPaY (ORCPT ); Wed, 7 Nov 2012 10:30:24 -0500 Date: Wed, 7 Nov 2012 16:30:23 +0100 From: Michal Hocko To: Tejun Heo Cc: lizefan@huawei.com, rjw@sisk.pl, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, fweisbec@gmail.com Subject: Re: [PATCH 2/9] cgroup: Use rculist ops for cgroup->children Message-ID: <20121107153023.GB4131@dhcp22.suse.cz> References: <1351931915-1701-1-git-send-email-tj@kernel.org> <1351931915-1701-3-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1351931915-1701-3-git-send-email-tj@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 03-11-12 01:38:28, Tejun Heo wrote: > Use RCU safe list operations for cgroup->children. This will be used > to implement cgroup children / descendant walking which can be used by > controllers. > > Note that cgroup_create() now puts a new cgroup at the end of the > ->children list instead of head. This isn't strictly necessary but is > done so that the iteration order is more conventional. > > Signed-off-by: Tejun Heo Reviewed-by: Michal Hocko > --- > include/linux/cgroup.h | 1 + > kernel/cgroup.c | 8 +++----- > 2 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h > index b442122..90c33eb 100644 > --- a/include/linux/cgroup.h > +++ b/include/linux/cgroup.h > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > #include > #include > #include > diff --git a/kernel/cgroup.c b/kernel/cgroup.c > index f05d992..cc5d2a0 100644 > --- a/kernel/cgroup.c > +++ b/kernel/cgroup.c > @@ -1650,7 +1650,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, > > free_cg_links(&tmp_cg_links); > > - BUG_ON(!list_empty(&root_cgrp->sibling)); > BUG_ON(!list_empty(&root_cgrp->children)); > BUG_ON(root->number_of_cgroups != 1); > > @@ -1699,7 +1698,6 @@ static void cgroup_kill_sb(struct super_block *sb) { > > BUG_ON(root->number_of_cgroups != 1); > BUG_ON(!list_empty(&cgrp->children)); > - BUG_ON(!list_empty(&cgrp->sibling)); > > mutex_lock(&cgroup_mutex); > mutex_lock(&cgroup_root_mutex); > @@ -4053,7 +4051,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, > } > } > > - list_add(&cgrp->sibling, &cgrp->parent->children); > + list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children); > root->number_of_cgroups++; > > err = cgroup_create_dir(cgrp, dentry, mode); > @@ -4084,7 +4082,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry, > > err_remove: > > - list_del(&cgrp->sibling); > + list_del_rcu(&cgrp->sibling); > root->number_of_cgroups--; > > err_destroy: > @@ -4210,7 +4208,7 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) > raw_spin_unlock(&release_list_lock); > > /* delete this cgroup from parent->children */ > - list_del_init(&cgrp->sibling); > + list_del_rcu(&cgrp->sibling); > > list_del_init(&cgrp->allcg_node); > > -- > 1.7.11.7 > -- Michal Hocko SUSE Labs