cgroup: make hierarchy_id use cyclic idr (1a574231) · Commits · 戴 / test

kernel/cgroup.c

+8 −20

Original line number	Diff line number	Diff line
		@@ -194,8 +194,7 @@ static int root_count;
		* rules as other root ops - both cgroup_mutex and cgroup_root_mutex for
		* writes, either for reads.
		*/
		static DEFINE_IDA(hierarchy_ida);
		static int next_hierarchy_id;
		static DEFINE_IDR(cgroup_hierarchy_idr);

		/* dummytop is a shorthand for the dummy hierarchy's top cgroup */
		#define dummytop (&rootnode.top_cgroup)
		@@ -1432,27 +1431,16 @@ static void init_cgroup_root(struct cgroupfs_root *root)

		static int cgroup_init_root_id(struct cgroupfs_root *root)
		{
		int ret;
		int id;

		lockdep_assert_held(&cgroup_mutex);
		lockdep_assert_held(&cgroup_root_mutex);

		do {
		if (!ida_pre_get(&hierarchy_ida, GFP_KERNEL))
		return -ENOMEM;
		/* Try to allocate the next unused ID */
		ret = ida_get_new_above(&hierarchy_ida, next_hierarchy_id,
		&root->hierarchy_id);
		if (ret == -ENOSPC)
		/* Try again starting from 0 */
		ret = ida_get_new(&hierarchy_ida, &root->hierarchy_id);
		if (!ret) {
		next_hierarchy_id = root->hierarchy_id + 1;
		} else if (ret != -EAGAIN) {
		/* Can only get here if the 31-bit IDR is full ... */
		BUG_ON(ret);
		}
		} while (ret);
		id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, 2, 0, GFP_KERNEL);
		if (id < 0)
		return id;

		root->hierarchy_id = id;
		return 0;
		}

		@@ -1462,7 +1450,7 @@ static void cgroup_exit_root_id(struct cgroupfs_root *root)
		lockdep_assert_held(&cgroup_root_mutex);

		if (root->hierarchy_id) {
		ida_remove(&hierarchy_ida, root->hierarchy_id);
		idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
		root->hierarchy_id = 0;
		}
		}