From d98817d4961b9ef75062d1e129829d283b3dac57 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 13:58:16 -0700 Subject: [PATCH] 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: Tejun Heo Acked-by: Li Zefan Cc: Johannes Weiner Cc: cgroups@vger.kernel.org --- kernel/cgroup.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 3f6641632f73..d9f854defa78 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1333,9 +1333,10 @@ static int cgroup_show_options(struct seq_file *seq, struct cgroup_subsys *ss; int ssid; - for_each_subsys(ss, ssid) - if (root->subsys_mask & (1 << ssid)) - seq_printf(seq, ",%s", ss->name); + if (root != &cgrp_dfl_root) + for_each_subsys(ss, ssid) + if (root->subsys_mask & (1 << ssid)) + seq_printf(seq, ",%s", ss->name); if (root->flags & CGRP_ROOT_NOPREFIX) seq_puts(seq, ",noprefix"); if (root->flags & CGRP_ROOT_XATTR) @@ -5137,9 +5138,11 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, continue; seq_printf(m, "%d:", root->hierarchy_id); - for_each_subsys(ss, ssid) - if (root->subsys_mask & (1 << ssid)) - seq_printf(m, "%s%s", count++ ? "," : "", ss->name); + if (root != &cgrp_dfl_root) + for_each_subsys(ss, ssid) + if (root->subsys_mask & (1 << ssid)) + seq_printf(m, "%s%s", count++ ? "," : "", + ss->name); if (strlen(root->name)) seq_printf(m, "%sname=%s", count ? "," : "", root->name); -- 2.20.1