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authorTejun Heo <tj@kernel.org>2017-07-23 08:18:26 -0400
committerTejun Heo <tj@kernel.org>2017-07-25 13:15:29 -0400
commit918a8c2c4ea4fab8b7855b8da48bbaf0a733ebb0 (patch)
tree55b740ec2319dc2a358e86a6b0323a6a71786a5c /kernel/cgroup
parent7a0cf0e74ab6cfd8e561f5f12860d4ff8844905a (diff)
downloadlinux-918a8c2c4ea4fab8b7855b8da48bbaf0a733ebb0.tar.bz2
cgroup: remove unnecessary empty check when enabling threaded mode
cgroup_enable_threaded() checks that the cgroup doesn't have any tasks or children and fails the operation if so. This test is unnecessary because the first part is already checked by cgroup_can_be_thread_root() and the latter is unnecessary. The latter actually cause a behavioral oddity. Please consider the following hierarchy. All cgroups are domains. A / \ B C \ D If B is made threaded, C and D becomes invalid domains. Due to the no children restriction, threaded mode can't be enabled on C. For C and D, the only thing the user can do is removal. There is no reason for this restriction. Remove it. Acked-by: Waiman Long <longman@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/cgroup')
-rw-r--r--kernel/cgroup/cgroup.c7
1 files changed, 0 insertions, 7 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index e9a377dc5bdb..e0a558c4d358 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -3147,13 +3147,6 @@ static int cgroup_enable_threaded(struct cgroup *cgrp)
return -EOPNOTSUPP;
/*
- * Allow enabling thread mode only on empty cgroups to avoid
- * implicit migrations and recursive operations.
- */
- if (cgroup_has_tasks(cgrp) || css_has_online_children(&cgrp->self))
- return -EBUSY;
-
- /*
* The following shouldn't cause actual migrations and should
* always succeed.
*/