Re: [PATCH 2/9] cgroup: Use rculist ops for cgroup->children
From: Michal Hocko <hidden>
Date: 2012-11-07 15:30:25
Also in:
linux-pm, lkml
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 <tj@kernel.org>
Reviewed-by: Michal Hocko <redacted>
quoted hunk ↗ jump to hunk
--- 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 <linux/cpumask.h> #include <linux/nodemask.h> #include <linux/rcupdate.h> +#include <linux/rculist.h> #include <linux/cgroupstats.h> #include <linux/prio_heap.h> #include <linux/rwsem.h>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