With major controllers - cpu, memory and io - shaping up for the
unified hierarchy, cgroup2 is about ready to be, gradually, released
into the wild. Replace __DEVEL__sane_behavior flag which was used to
select the unified hierarchy with a separate filesystem type "cgroup2"
so that unified hierarchy can be mounted as follows.
mount -t cgroup2 none $MOUNT_POINT
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Li Zefan <lizefan@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
---
Documentation/cgroups/unified-hierarchy.txt | 6 +--
include/linux/cgroup-defs.h | 1
kernel/cgroup.c | 43 +++++++++++++---------------
3 files changed, 22 insertions(+), 28 deletions(-)
--- a/Documentation/cgroups/unified-hierarchy.txt
+++ b/Documentation/cgroups/unified-hierarchy.txt
@@ -94,11 +94,9 @@ the process.
2-1. Mounting
-Currently, unified hierarchy can be mounted with the following mount
-command. Note that this is still under development and scheduled to
-change soon.
+Unified hierarchy can be mounted with the following mount command.
- mount -t cgroup -o __DEVEL__sane_behavior cgroup $MOUNT_POINT
+ mount -t cgroup2 none $MOUNT_POINT
All controllers which support the unified hierarchy and are not bound
to other hierarchies are automatically bound to unified hierarchy and
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -66,7 +66,6 @@ enum {
/* cgroup_root->flags */
enum {
- CGRP_ROOT_SANE_BEHAVIOR = (1 << 0), /* __DEVEL__sane_behavior specified */
CGRP_ROOT_NOPREFIX = (1 << 1), /* mounted subsystems have no named prefix */
CGRP_ROOT_XATTR = (1 << 2), /* supports extended attributes */
};
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -183,6 +183,7 @@ static unsigned long have_exit_callback
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
+static struct file_system_type cgroup2_fs_type;
static struct cftype cgroup_dfl_base_files[];
static struct cftype cgroup_legacy_base_files[];
@@ -1391,10 +1392,6 @@ static int parse_cgroupfs_options(char *
all_ss = true;
continue;
}
- if (!strcmp(token, "__DEVEL__sane_behavior")) {
- opts->flags |= CGRP_ROOT_SANE_BEHAVIOR;
- continue;
- }
if (!strcmp(token, "noprefix")) {
opts->flags |= CGRP_ROOT_NOPREFIX;
continue;
@@ -1461,15 +1458,6 @@ static int parse_cgroupfs_options(char *
return -ENOENT;
}
- if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) {
- pr_warn("sane_behavior: this is still under development and its behaviors will change, proceed at your own risk\n");
- if (nr_opts != 1) {
- pr_err("sane_behavior: no other mount options allowed\n");
- return -EINVAL;
- }
- return 0;
- }
-
/*
* If the 'all' option was specified select all the subsystems,
* otherwise if 'none', 'name=' and a subsystem name options were
@@ -1765,6 +1753,17 @@ static struct dentry *cgroup_mount(struc
if (!use_task_css_set_links)
cgroup_enable_task_cg_lists();
+ if (fs_type == &cgroup2_fs_type) {
+ if (data) {
+ pr_err("cgroup2: unknown option \"%s\"\n", (char *)data);
+ return ERR_PTR(-EINVAL);
+ }
+ cgrp_dfl_root_visible = true;
+ root = &cgrp_dfl_root;
+ cgroup_get(&root->cgrp);
+ goto out_mount;
+ }
+
mutex_lock(&cgroup_mutex);
/* First find the desired set of subsystems */
@@ -1772,15 +1771,6 @@ static struct dentry *cgroup_mount(struc
if (ret)
goto out_unlock;
- /* look for a matching existing root */
- if (opts.flags & CGRP_ROOT_SANE_BEHAVIOR) {
- cgrp_dfl_root_visible = true;
- root = &cgrp_dfl_root;
- cgroup_get(&root->cgrp);
- ret = 0;
- goto out_unlock;
- }
-
/*
* Destruction of cgroup root is asynchronous, so subsystems may
* still be dying after the previous unmount. Let's drain the
@@ -1891,7 +1881,7 @@ out_free:
if (ret)
return ERR_PTR(ret);
-
+out_mount:
dentry = kernfs_mount(fs_type, flags, root->kf_root,
CGROUP_SUPER_MAGIC, &new_sb);
if (IS_ERR(dentry) || !new_sb)
@@ -1936,6 +1926,12 @@ static struct file_system_type cgroup_fs
.kill_sb = cgroup_kill_sb,
};
+static struct file_system_type cgroup2_fs_type = {
+ .name = "cgroup2",
+ .mount = cgroup_mount,
+ .kill_sb = cgroup_kill_sb,
+};
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -5056,6 +5052,7 @@ int __init cgroup_init(void)
WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup"));
WARN_ON(register_filesystem(&cgroup_fs_type));
+ WARN_ON(register_filesystem(&cgroup2_fs_type));
WARN_ON(!proc_create("cgroups", 0, NULL, &proc_cgroupstats_operations));
return 0;
--
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