The next patch will use it to determine if a cgroup is newly created
while we're iterating the cgroup hierarchy.
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
---
These two patches are based on the fixes I just sent.
---
kernel/cgroup.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index e8a40e3..b1d98f2 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. It guarantees
+ * cgroups with bigger numbers are newer than those with smaller
+ * numbers. Also with the list appending, it guarantees that sibling
+ * cgroups are always sorted in the ascending serial number order on
+ * the parent's ->children.
+ */
+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
@@ -4212,7 +4221,6 @@ 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;
@@ -4305,7 +4313,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
* 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);
--
1.8.0.2
--
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