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authorLi Zefan <lizefan@huawei.com>2013-06-18 18:53:53 +0800
committerTejun Heo <tj@kernel.org>2013-06-18 11:14:21 -0700
commit794611a1dfcb055d7d41ce133378dd8197d73e38 (patch)
treec89867196b18237422fddf6c62862de08038838a /kernel/cgroup.c
parentf57947d27711451a7739a25bba6cddc8a385e438 (diff)
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>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 1d4f471de8d5..e6571ca822a0 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -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);