[PATCH 5/7] cgroup: make debug an implicit controller on cgroup2

Tejun Heo
2017-06-14T20:09:11Z

Make debug an implicit controller on cgroup2 which is enabled by
"cgroup_debug" boot param.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
---
kernel/cgroup/debug.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 56 insertions(+), 3 deletions(-)

diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
index 057d9b07f461..d61e692a5338 100644
--- a/kernel/cgroup/debug.c
+++ b/kernel/cgroup/debug.c
@@ -240,7 +240,7 @@ static u64 releasable_read(struct cgroup_subsys_state *css, struct cftype *cft)
!css_has_online_children(&css->cgroup->self));
}

-static struct cftype debug_files[] = {
+static struct cftype debug_legacy_files[] = {
{
.name = "taskcount",
.read_u64 = debug_taskcount_read,
@@ -287,9 +287,62 @@ static struct cftype debug_files[] = {
{ } /* terminate */
};

+static struct cftype debug_files[] = {
+ {
+ .name = "taskcount",
+ .read_u64 = debug_taskcount_read,
+ },
+
+ {
+ .name = "current_css_set",
+ .seq_show = current_css_set_read,
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ },
+
+ {
+ .name = "current_css_set_refcount",
+ .read_u64 = current_css_set_refcount_read,
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ },
+
+ {
+ .name = "current_css_set_cg_links",
+ .seq_show = current_css_set_cg_links_read,
+ .flags = CFTYPE_ONLY_ON_ROOT,
+ },
+
+ {
+ .name = "css_links",
+ .seq_show = cgroup_css_links_read,
+ },
+
+ {
+ .name = "csses",
+ .seq_show = cgroup_subsys_states_read,
+ },
+
+ {
+ .name = "masks",
+ .seq_show = cgroup_masks_read,
+ },
+
+ { } /* terminate */
+};
+
struct cgroup_subsys debug_cgrp_subsys = {
.css_alloc = debug_css_alloc,
.css_free = debug_css_free,
- .legacy_cftypes = debug_files,
- .dfl_cftypes = debug_files,
+ .legacy_cftypes = debug_legacy_files,
};
+
+/*
+ * On v2, debug is an implicit controller enabled by "cgroup_debug" boot
+ * parameter.
+ */
+static int __init enable_cgroup_debug(char *str)
+{
+ debug_cgrp_subsys.dfl_cftypes = debug_files;
+ debug_cgrp_subsys.implicit_on_dfl = true;
+ return 1;
+}
+__setup("cgroup_debug", enable_cgroup_debug);
--
2.13.0