[PATCH cgroup/for-4.21 2/2] cgroup: Add .__DEBUG__. prefix to debug file names

[Tejun Heo]

>From c1bbd933e5fae83f96acd3f748bb01a0300b315d Mon Sep 17 00:00:00 2001
From: Tejun Heo <t...@kernel.org>
Date: Tue, 13 Nov 2018 12:06:41 -0800

Clearly mark the debug files and hide them by default by prefixing
".__DEBUG__.".

Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Waiman Long <long...@redhat.com>
---
 kernel/cgroup/cgroup.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index ed7f0bfe6429..e06994fd4e34 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1400,12 +1400,15 @@ static char *cgroup_file_name(struct cgroup *cgrp, 
const struct cftype *cft,
        struct cgroup_subsys *ss = cft->ss;
 
        if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
-           !(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
-               snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
-                        cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
+           !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
+               const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : 
"";
+
+               snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
+                        dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
                         cft->name);
-       else
+       } else {
                strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
+       }
        return buf;
 }
 
-- 
2.17.1