cgroup: don't print subsystems for the default hierarchy (d98817d4) · Commits · 戴 / test

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:

Tejun Heo <tj@kernel.org> Acked-by:

Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: cgroups@vger.kernel.org

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);

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