cgroup: make serial_nr_cursor available throughout cgroup.c

The next patch will use it to determine if a cgroup is newly created
while we're iterating the cgroup hierarchy.

tj: Rephrased the comment on top of cgroup_serial_nr_cursor.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Li Zefan 2013-06-18 18:53:53 +08:00 committed by Tejun Heo
parent f57947d277
commit 794611a1df

View File

@ -198,6 +198,15 @@ static DEFINE_IDR(cgroup_hierarchy_idr);
static struct cgroup_name root_cgroup_name = { .name = "/" };
/*
* Assign a monotonically increasing serial number to cgroups. It
* guarantees cgroups with bigger numbers are newer than those with smaller
* numbers. Also, as cgroups are always appended to the parent's
* ->children list, it guarantees that sibling cgroups are always sorted in
* the ascending serial number order on the list.
*/
static atomic64_t cgroup_serial_nr_cursor = ATOMIC64_INIT(0);
/* This flag indicates whether tasks in the fork and exit paths should
* check for fork/exit handlers to call. This avoids us having to do
* extra work in the fork/exit path if none of the subsystems need to
@ -4222,7 +4231,6 @@ static void offline_css(struct cgroup_subsys *ss, struct cgroup *cgrp)
static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
umode_t mode)
{
static atomic64_t serial_nr_cursor = ATOMIC64_INIT(0);
struct cgroup *cgrp;
struct cgroup_name *name;
struct cgroupfs_root *root = parent->root;
@ -4309,13 +4317,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
goto err_free_all;
lockdep_assert_held(&dentry->d_inode->i_mutex);
/*
* Assign a monotonically increasing serial number. With the list
* appending below, it guarantees that sibling cgroups are always
* sorted in the ascending serial number order on the parent's
* ->children.
*/
cgrp->serial_nr = atomic64_inc_return(&serial_nr_cursor);
cgrp->serial_nr = atomic64_inc_return(&cgroup_serial_nr_cursor);
/* allocation complete, commit to creation */
list_add_tail(&cgrp->allcg_node, &root->allcg_list);