cgroup: build list of all cgroups under a given cgroupfs_root

Build a list of all cgroups anchored at cgroupfs_root->allcg_list and
going through cgroup->allcg_node.  The list is protected by
cgroup_mutex and will be used to improve cgroup file handling.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
This commit is contained in:
Tejun Heo 2012-04-01 12:09:54 -07:00
parent ff4c8d503e
commit b0ca5a84fc
2 changed files with 12 additions and 0 deletions

View File

@ -191,6 +191,8 @@ struct cgroup {
*/
struct list_head css_sets;
struct list_head allcg_node; /* cgroupfs_root->allcg_list */
/*
* Linked list running through all cgroups that can
* potentially be reaped by the release agent. Protected by

View File

@ -127,6 +127,9 @@ struct cgroupfs_root {
/* A list running through the active hierarchies */
struct list_head root_list;
/* All cgroups on this root, cgroup_mutex protected */
struct list_head allcg_list;
/* Hierarchy-specific flags */
unsigned long flags;
@ -1350,11 +1353,14 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
static void init_cgroup_root(struct cgroupfs_root *root)
{
struct cgroup *cgrp = &root->top_cgroup;
INIT_LIST_HEAD(&root->subsys_list);
INIT_LIST_HEAD(&root->root_list);
INIT_LIST_HEAD(&root->allcg_list);
root->number_of_cgroups = 1;
cgrp->root = root;
cgrp->top_cgroup = cgrp;
list_add_tail(&cgrp->allcg_node, &root->allcg_list);
init_cgroup_housekeeping(cgrp);
}
@ -3790,6 +3796,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
/* The cgroup directory was pre-locked for us */
BUG_ON(!mutex_is_locked(&cgrp->dentry->d_inode->i_mutex));
list_add_tail(&cgrp->allcg_node, &root->allcg_list);
err = cgroup_populate_dir(cgrp);
/* If err < 0, we have a half-filled directory - oh well ;) */
@ -3998,6 +4006,8 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
list_del_init(&cgrp->sibling);
cgroup_unlock_hierarchy(cgrp->root);
list_del_init(&cgrp->allcg_node);
d = dget(cgrp->dentry);
cgroup_d_remove_dir(d);