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Commit d98817d4 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: don't print subsystems for the default hierarchy 



It doesn't make sense to print subsystems on mount option or
/proc/PID/cgroup for the default hierarchy.

* cgroup.controllers file at the root of the default hierarchy lists
  the currently attached controllers.

* The default hierarchy is catch-all for unmounted subsystems.

* The default hierarchy doesn't accept any mount options.

Suppress subsystem printing on mount options and /proc/PID/cgroup for
the default hierarchy.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
parent 731a981e

kernel/cgroup.c

+9 −6
Original line number Diff line number Diff line
@@ -1333,6 +1333,7 @@ static int cgroup_show_options(struct seq_file *seq, 
	struct cgroup_subsys *ss;

	int ssid;



	if (root != &cgrp_dfl_root)

		for_each_subsys(ss, ssid)

			if (root->subsys_mask & (1 << ssid))

				seq_printf(seq, ",%s", ss->name);
@@ -5137,9 +5138,11 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, 
			continue;



		seq_printf(m, "%d:", root->hierarchy_id);

		if (root != &cgrp_dfl_root)

			for_each_subsys(ss, ssid)

				if (root->subsys_mask & (1 << ssid))

				seq_printf(m, "%s%s", count++ ? "," : "", ss->name);

					seq_printf(m, "%s%s", count++ ? "," : "",

						   ss->name);

		if (strlen(root->name))

			seq_printf(m, "%sname=%s", count ? "," : "",

				   root->name);