From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 2/9] cgroup: Use rculist ops for cgroup->children Date: Sat, 3 Nov 2012 01:38:28 -0700 Message-ID: <1351931915-1701-3-git-send-email-tj@kernel.org> References: <1351931915-1701-1-git-send-email-tj@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1351931915-1701-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, mhocko-AlSwsSmVLrQ@public.gmane.org, rjw-KKrjLPT3xs0@public.gmane.org Cc: linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-pm@vger.kernel.org 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 --- 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