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>
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 5a85b34..ad2a1468 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -191,6 +191,8 @@
*/
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
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8f72853..db4319c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -127,6 +127,9 @@
/* 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_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 @@
/* 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 @@
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);
