cgroup: add css_set->dfl_cgrp

To implement the unified hierarchy behavior, we'll need to be able to determine the associated cgroup on the default hierarchy from css_set. Let's add css_set->dfl_cgrp so that it can be accessed conveniently and efficiently. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>

cgroup: add css_set->dfl_cgrp
To implement the unified hierarchy behavior, we'll need to be able to determine the associated cgroup on the default hierarchy from css_set. Let's add css_set->dfl_cgrp so that it can be accessed conveniently and efficiently. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
Tejun Heo
1 parent bd53d617b3
Showing 2 changed files with 7 additions and 0 deletions Side-by-side Diff
include/linux/cgroup.h
kernel/cgroup.c
@@ -354,6 +354,9 @@
 	 */
 	struct list_head cgrp_links;
  
+	/* the default cgroup associated with this css_set */
+	struct cgroup *dfl_cgrp;
+
 	/*
 	 * Set of subsystem states, one for each subsystem. This array is
 	 * immutable after creation apart from the init_css_set during
@@ -651,6 +651,10 @@
 	struct cgrp_cset_link *link;
  
 	BUG_ON(list_empty(tmp_links));
+
+	if (cgroup_on_dfl(cgrp))
+		cset->dfl_cgrp = cgrp;
+
 	link = list_first_entry(tmp_links, struct cgrp_cset_link, cset_link);
 	link->cset = cset;
 	link->cgrp = cgrp;
...	...	@@ -354,6 +354,9 @@
354	354	*/
355	355	struct list_head cgrp_links;
356	356
	357	+ /* the default cgroup associated with this css_set */
	358	+ struct cgroup *dfl_cgrp;
	359	+
357	360	/*
358	361	* Set of subsystem states, one for each subsystem. This array is
359	362	* immutable after creation apart from the init_css_set during
...	...	@@ -651,6 +651,10 @@
651	651	struct cgrp_cset_link *link;
652	652
653	653	BUG_ON(list_empty(tmp_links));
	654	+
	655	+ if (cgroup_on_dfl(cgrp))
	656	+ cset->dfl_cgrp = cgrp;
	657	+
654	658	link = list_first_entry(tmp_links, struct cgrp_cset_link, cset_link);
655	659	link->cset = cset;
656	660	link->cgrp = cgrp;