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authorTejun Heo <tj@kernel.org>2014-05-04 15:09:13 -0400
committerTejun Heo <tj@kernel.org>2014-05-04 15:09:13 -0400
commit7d699ddb2b181a2c76e5ea18b1bdf102c4bebe4b (patch)
tree0811810b37ff735921b689aa1ca273ecf253e29c /kernel/cgroup.c
parent69dfa00ccb72a37f3810687ca110e5a8154c6eed (diff)
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cgroup, memcg: allocate cgroup ID from 1
Currently, cgroup->id is allocated from 0, which is always assigned to the root cgroup; unfortunately, memcg wants to use ID 0 to indicate invalid IDs and ends up incrementing all IDs by one. It's reasonable to reserve 0 for special purposes. This patch updates cgroup core so that ID 0 is not used and the root cgroups get ID 1. The ID incrementing is removed form memcg. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'kernel/cgroup.c')
-rw-r--r--kernel/cgroup.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 21667f396a1e..3fa0463e74bb 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1531,7 +1531,7 @@ static int cgroup_setup_root(struct cgroup_root *root, unsigned int ss_mask)
lockdep_assert_held(&cgroup_tree_mutex);
lockdep_assert_held(&cgroup_mutex);
- ret = idr_alloc(&root->cgroup_idr, root_cgrp, 0, 1, GFP_KERNEL);
+ ret = idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_KERNEL);
if (ret < 0)
goto out;
root_cgrp->id = ret;
@@ -4225,7 +4225,7 @@ static long cgroup_create(struct cgroup *parent, const char *name,
* Temporarily set the pointer to NULL, so idr_find() won't return
* a half-baked cgroup.
*/
- cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 1, 0, GFP_KERNEL);
+ cgrp->id = idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_KERNEL);
if (cgrp->id < 0) {
err = -ENOMEM;
goto err_unlock;