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Commit 794611a1 authored by Li Zefan's avatar Li Zefan Committed by Tejun Heo
Browse files

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: default avatarLi Zefan <lizefan@huawei.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent f57947d2

kernel/cgroup.c

+10 −8
Original line number Diff line number Diff line
@@ -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);