From 3e1d2eed39d804e48282931835c7203fa47fe1d9 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 18 Aug 2015 13:58:16 -0700 Subject: [PATCH] cgroup: introduce cgroup_subsys->legacy_name This allows cgroup subsystems to use a different name on the unified hierarchy. cgroup_subsys->name is used on the unified hierarchy, ->legacy_name elsewhere. If ->legacy_name is not explicitly set, it's automatically set to ->name and the userland visible behavior remains unchanged. v2: Make parse_cgroupfs_options() only consider ->legacy_name as mount options are used only on legacy hierarchies. Suggested by Li Zefan. Signed-off-by: Tejun Heo Acked-by: Li Zefan Cc: Johannes Weiner Cc: cgroups@vger.kernel.org --- include/linux/cgroup-defs.h | 3 +++ kernel/cgroup.c | 29 ++++++++++++++++++----------- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 8f5770a7d85a..7d0bb53e4553 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -434,6 +434,9 @@ struct cgroup_subsys { int id; const char *name; + /* optional, initialized automatically during boot if not set */ + const char *legacy_name; + /* link to parent, protected by cgroup_lock() */ struct cgroup_root *root; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index d9f854defa78..9c8eb17d593a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1028,10 +1028,13 @@ static const struct file_operations proc_cgroupstats_operations; static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft, char *buf) { + 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", - cft->ss->name, cft->name); + cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name, + cft->name); else strncpy(buf, cft->name, CGROUP_FILE_NAME_MAX); return buf; @@ -1336,7 +1339,7 @@ static int cgroup_show_options(struct seq_file *seq, if (root != &cgrp_dfl_root) for_each_subsys(ss, ssid) if (root->subsys_mask & (1 << ssid)) - seq_printf(seq, ",%s", ss->name); + seq_printf(seq, ",%s", ss->legacy_name); if (root->flags & CGRP_ROOT_NOPREFIX) seq_puts(seq, ",noprefix"); if (root->flags & CGRP_ROOT_XATTR) @@ -1449,7 +1452,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) } for_each_subsys(ss, i) { - if (strcmp(token, ss->name)) + if (strcmp(token, ss->legacy_name)) continue; if (ss->disabled) continue; @@ -4995,6 +4998,8 @@ int __init cgroup_init_early(void) ss->id = i; ss->name = cgroup_subsys_name[i]; + if (!ss->legacy_name) + ss->legacy_name = cgroup_subsys_name[i]; if (ss->early_init) cgroup_init_subsys(ss, true); @@ -5142,7 +5147,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns, for_each_subsys(ss, ssid) if (root->subsys_mask & (1 << ssid)) seq_printf(m, "%s%s", count++ ? "," : "", - ss->name); + ss->legacy_name); if (strlen(root->name)) seq_printf(m, "%sname=%s", count ? "," : "", root->name); @@ -5182,7 +5187,7 @@ static int proc_cgroupstats_show(struct seq_file *m, void *v) for_each_subsys(ss, i) seq_printf(m, "%s\t%d\t%d\t%d\n", - ss->name, ss->root->hierarchy_id, + ss->legacy_name, ss->root->hierarchy_id, atomic_read(&ss->root->nr_cgrps), !ss->disabled); mutex_unlock(&cgroup_mutex); @@ -5404,12 +5409,14 @@ static int __init cgroup_disable(char *str) continue; for_each_subsys(ss, i) { - if (!strcmp(token, ss->name)) { - ss->disabled = 1; - printk(KERN_INFO "Disabling %s control group" - " subsystem\n", ss->name); - break; - } + if (strcmp(token, ss->name) && + strcmp(token, ss->legacy_name)) + continue; + + ss->disabled = 1; + printk(KERN_INFO "Disabling %s control group subsystem\n", + ss->name); + break; } } return 1; -- 2.20.1