From 67e9c74b8a873408c27ac9a8e4c1d1c8d72c93ff Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 16 Nov 2015 11:13:34 -0500 Subject: [PATCH] cgroup: replace __DEVEL__sane_behavior with cgroup2 fs type 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 The cgroup2 fs has its own magic number - 0x63677270 ("cgrp"). v2: Assign a different magic number to cgroup2 fs. Signed-off-by: Tejun Heo Acked-by: Li Zefan Cc: Johannes Weiner --- Documentation/cgroups/unified-hierarchy.txt | 6 +-- include/linux/cgroup-defs.h | 1 - include/uapi/linux/magic.h | 1 + kernel/cgroup.c | 47 ++++++++++----------- 4 files changed, 26 insertions(+), 29 deletions(-) diff --git a/Documentation/cgroups/unified-hierarchy.txt b/Documentation/cgroups/unified-hierarchy.txt index 781b1d475bcf..c1f0e8780960 100644 --- 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 diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 869fd4a3d28e..80e2ae655208 100644 --- 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 */ }; diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index accb036bbc9c..b283d56c1db9 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -54,6 +54,7 @@ #define SMB_SUPER_MAGIC 0x517B #define CGROUP_SUPER_MAGIC 0x27e0eb +#define CGROUP2_SUPER_MAGIC 0x63677270 #define STACK_END_MAGIC 0x57AC6E9D diff --git a/kernel/cgroup.c b/kernel/cgroup.c index b316debadeb3..af0886262f58 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -211,6 +211,7 @@ static unsigned long have_free_callback __read_mostly; /* 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[]; @@ -1641,10 +1642,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) 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; @@ -1711,15 +1708,6 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts) 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 @@ -1998,6 +1986,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, int flags, const char *unused_dev_name, void *data) { + bool is_v2 = fs_type == &cgroup2_fs_type; struct super_block *pinned_sb = NULL; struct cgroup_subsys *ss; struct cgroup_root *root; @@ -2014,6 +2003,17 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, if (!use_task_css_set_links) cgroup_enable_task_cg_lists(); + if (is_v2) { + 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 */ @@ -2021,15 +2021,6 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, 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 @@ -2140,9 +2131,10 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type, if (ret) return ERR_PTR(ret); - +out_mount: dentry = kernfs_mount(fs_type, flags, root->kf_root, - CGROUP_SUPER_MAGIC, &new_sb); + is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC, + &new_sb); if (IS_ERR(dentry) || !new_sb) cgroup_put(&root->cgrp); @@ -2185,6 +2177,12 @@ static struct file_system_type cgroup_fs_type = { .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 @@ -5315,6 +5313,7 @@ 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; -- GitLab