cgroup: use rculist ops for cgroup->children

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 <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
This commit is contained in:
Tejun Heo 2012-11-09 09:12:29 -08:00
parent a8638030f6
commit eb6fd5040e
2 changed files with 4 additions and 5 deletions

View File

@ -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>

View File

@ -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);
@ -4052,7 +4050,7 @@ 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);
@ -4083,7 +4081,7 @@ 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:
@ -4209,7 +4207,7 @@ 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);