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cgroup: introduce cgroup_subsys->legacy_name

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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 <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
This commit is contained in:
Tejun Heo 2015-08-18 13:58:16 -07:00
parent d98817d496
commit 3e1d2eed39
2 changed files with 21 additions and 11 deletions
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3
include/linux/cgroup-defs.h
View file

@ -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;

29
kernel/cgroup.c
View file

@ -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;