cpuset: remove fast exit path from remove_tasks_in_empty_cpuset()

The function isn't that hot, the overhead of missing the fast exit is
low, the test itself depends heavily on cgroup internals, and it's
gonna be a hindrance when trying to decouple cpuset locking from
cgroup core.  Remove the fast exit path.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 854b8bfbc15c0c7edf159bab527972ad9b3aab16..5372b6f5e5b3ed91224b55f41ab4d0a2ded1557c 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -1967,14 +1967,6 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
 {
        struct cpuset *parent;
 
-       /*
-        * The cgroup's css_sets list is in use if there are tasks
-        * in the cpuset; the list is empty if there are none;
-        * the cs->css.refcnt seems always 0.
-        */
-       if (list_empty(&cs->css.cgroup->css_sets))
-               return;
-
        /*
         * Find its next-highest non-empty parent, (top cpuset
         * has online cpus, so can't be empty).