cgroup: mark "tasks" cgroup file as insane

Some resources controlled by cgroup aren't per-task and cgroup core
allowing threads of a single thread_group to be in different cgroups
forced memcg do explicitly find the group leader and use it.  This is
gonna be nasty when transitioning to unified hierarchy and in general
we don't want and won't support granularity finer than processes.

Mark "tasks" with CFTYPE_INSANE.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: cgroups@vger.kernel.org
Cc: Vivek Goyal <vgoyal@redhat.com>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fefc41c1a147fa6a3ff64c185aaf045974dfadb3..1e0f445b5b887750e8a39d07ca164fc4e0b51ed9 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4037,6 +4037,7 @@ static int cgroup_clone_children_write(struct cgroup *cgrp,
 static struct cftype files[] = {
        {
                .name = "tasks",
+               .flags = CFTYPE_INSANE,         /* use "procs" instead */
                .open = cgroup_tasks_open,
                .write_u64 = cgroup_tasks_write,
                .release = cgroup_pidlist_release,