Task Control Groups: make cpusets a client of cgroups

Remove the filesystem support logic from the cpusets system and makes cpusets
a cgroup subsystem

The "cpuset" filesystem becomes a dummy filesystem; attempts to mount it get
passed through to the cgroup filesystem with the appropriate options to
emulate the old cpuset filesystem behaviour.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

11 files changed, 277 insertions, 1055 deletions

diff --git a/Documentation/cpusets.txt b/Documentation/cpusets.txt
index ec9de6917f0..85eeab5e7e3 100644
--- a/Documentation/cpusets.txt
+++ b/Documentation/cpusets.txt
@@ -7,6 +7,7 @@ Written by Simon.Derr@bull.net
 Portions Copyright (c) 2004-2006 Silicon Graphics, Inc.
 Modified by Paul Jackson <pj@sgi.com>
 Modified by Christoph Lameter <clameter@sgi.com>
+Modified by Paul Menage <menage@google.com>
 
 CONTENTS:
 =========
@@ -16,10 +17,9 @@ CONTENTS:
   1.2 Why are cpusets needed ?
   1.3 How are cpusets implemented ?
   1.4 What are exclusive cpusets ?
-  1.5 What does notify_on_release do ?
-  1.6 What is memory_pressure ?
-  1.7 What is memory spread ?
-  1.8 How do I use cpusets ?
+  1.5 What is memory_pressure ?
+  1.6 What is memory spread ?
+  1.7 How do I use cpusets ?
 2. Usage Examples and Syntax
   2.1 Basic Usage
   2.2 Adding/removing cpus
@@ -44,18 +44,19 @@ hierarchy visible in a virtual file system.  These are the essential
 hooks, beyond what is already present, required to manage dynamic
 job placement on large systems.
 
-Each task has a pointer to a cpuset.  Multiple tasks may reference
-the same cpuset.  Requests by a task, using the sched_setaffinity(2)
-system call to include CPUs in its CPU affinity mask, and using the
-mbind(2) and set_mempolicy(2) system calls to include Memory Nodes
-in its memory policy, are both filtered through that tasks cpuset,
-filtering out any CPUs or Memory Nodes not in that cpuset.  The
-scheduler will not schedule a task on a CPU that is not allowed in
-its cpus_allowed vector, and the kernel page allocator will not
-allocate a page on a node that is not allowed in the requesting tasks
-mems_allowed vector.
-
-User level code may create and destroy cpusets by name in the cpuset
+Cpusets use the generic cgroup subsystem described in
+Documentation/cgroup.txt.
+
+Requests by a task, using the sched_setaffinity(2) system call to
+include CPUs in its CPU affinity mask, and using the mbind(2) and
+set_mempolicy(2) system calls to include Memory Nodes in its memory
+policy, are both filtered through that tasks cpuset, filtering out any
+CPUs or Memory Nodes not in that cpuset.  The scheduler will not
+schedule a task on a CPU that is not allowed in its cpus_allowed
+vector, and the kernel page allocator will not allocate a page on a
+node that is not allowed in the requesting tasks mems_allowed vector.
+
+User level code may create and destroy cpusets by name in the cgroup
 virtual file system, manage the attributes and permissions of these
 cpusets and which CPUs and Memory Nodes are assigned to each cpuset,
 specify and query to which cpuset a task is assigned, and list the
@@ -115,7 +116,7 @@ Cpusets extends these two mechanisms as follows:
  - Cpusets are sets of allowed CPUs and Memory Nodes, known to the
    kernel.
  - Each task in the system is attached to a cpuset, via a pointer
-   in the task structure to a reference counted cpuset structure.
+   in the task structure to a reference counted cgroup structure.
  - Calls to sched_setaffinity are filtered to just those CPUs
    allowed in that tasks cpuset.
  - Calls to mbind and set_mempolicy are filtered to just
@@ -145,15 +146,10 @@ into the rest of the kernel, none in performance critical paths:
  - in page_alloc.c, to restrict memory to allowed nodes.
  - in vmscan.c, to restrict page recovery to the current cpuset.
 
-In addition a new file system, of type "cpuset" may be mounted,
-typically at /dev/cpuset, to enable browsing and modifying the cpusets
-presently known to the kernel.  No new system calls are added for
-cpusets - all support for querying and modifying cpusets is via
-this cpuset file system.
-
-Each task under /proc has an added file named 'cpuset', displaying
-the cpuset name, as the path relative to the root of the cpuset file
-system.
+You should mount the "cgroup" filesystem type in order to enable
+browsing and modifying the cpusets presently known to the kernel.  No
+new system calls are added for cpusets - all support for querying and
+modifying cpusets is via this cpuset file system.
 
 The /proc/<pid>/status file for each task has two added lines,
 displaying the tasks cpus_allowed (on which CPUs it may be scheduled)
@@ -163,16 +159,15 @@ in the format seen in the following example:
   Cpus_allowed:   ffffffff,ffffffff,ffffffff,ffffffff
   Mems_allowed:   ffffffff,ffffffff
 
-Each cpuset is represented by a directory in the cpuset file system
-containing the following files describing that cpuset:
+Each cpuset is represented by a directory in the cgroup file system
+containing (on top of the standard cgroup files) the following
+files describing that cpuset:
 
  - cpus: list of CPUs in that cpuset
  - mems: list of Memory Nodes in that cpuset
  - memory_migrate flag: if set, move pages to cpusets nodes
  - cpu_exclusive flag: is cpu placement exclusive?
  - mem_exclusive flag: is memory placement exclusive?
- - tasks: list of tasks (by pid) attached to that cpuset
- - notify_on_release flag: run /sbin/cpuset_release_agent on exit?
  - memory_pressure: measure of how much paging pressure in cpuset
 
 In addition, the root cpuset only has the following file:
@@ -237,21 +232,7 @@ such as requests from interrupt handlers, is allowed to be taken
 outside even a mem_exclusive cpuset.
 
 
-1.5 What does notify_on_release do ?
-------------------------------------
-
-If the notify_on_release flag is enabled (1) in a cpuset, then whenever
-the last task in the cpuset leaves (exits or attaches to some other
-cpuset) and the last child cpuset of that cpuset is removed, then
-the kernel runs the command /sbin/cpuset_release_agent, supplying the
-pathname (relative to the mount point of the cpuset file system) of the
-abandoned cpuset.  This enables automatic removal of abandoned cpusets.
-The default value of notify_on_release in the root cpuset at system
-boot is disabled (0).  The default value of other cpusets at creation
-is the current value of their parents notify_on_release setting.
-
-
-1.6 What is memory_pressure ?
+1.5 What is memory_pressure ?
 -----------------------------
 The memory_pressure of a cpuset provides a simple per-cpuset metric
 of the rate that the tasks in a cpuset are attempting to free up in
@@ -308,7 +289,7 @@ the tasks in the cpuset, in units of reclaims attempted per second,
 times 1000.
 
 
-1.7 What is memory spread ?
+1.6 What is memory spread ?
 ---------------------------
 There are two boolean flag files per cpuset that control where the
 kernel allocates pages for the file system buffers and related in
@@ -379,7 +360,7 @@ data set, the memory allocation across the nodes in the jobs cpuset
 can become very uneven.
 
 
-1.8 How do I use cpusets ?
+1.7 How do I use cpusets ?
 --------------------------
 
 In order to minimize the impact of cpusets on critical kernel
@@ -469,7 +450,7 @@ than stress the kernel.
 To start a new job that is to be contained within a cpuset, the steps are:
 
  1) mkdir /dev/cpuset
- 2) mount -t cpuset none /dev/cpuset
+ 2) mount -t cgroup -ocpuset cpuset /dev/cpuset
  3) Create the new cpuset by doing mkdir's and write's (or echo's) in
     the /dev/cpuset virtual file system.
  4) Start a task that will be the "founding father" of the new job.
@@ -481,7 +462,7 @@ For example, the following sequence of commands will setup a cpuset
 named "Charlie", containing just CPUs 2 and 3, and Memory Node 1,
 and then start a subshell 'sh' in that cpuset:
 
-  mount -t cpuset none /dev/cpuset
+  mount -t cgroup -ocpuset cpuset /dev/cpuset
   cd /dev/cpuset
   mkdir Charlie
   cd Charlie
@@ -513,7 +494,7 @@ Creating, modifying, using the cpusets can be done through the cpuset
 virtual filesystem.
 
 To mount it, type:
-# mount -t cpuset none /dev/cpuset
+# mount -t cgroup -o cpuset cpuset /dev/cpuset
 
 Then under /dev/cpuset you can find a tree that corresponds to the
 tree of the cpusets in the system. For instance, /dev/cpuset
@@ -556,6 +537,18 @@ To remove a cpuset, just use rmdir:
 This will fail if the cpuset is in use (has cpusets inside, or has
 processes attached).
 
+Note that for legacy reasons, the "cpuset" filesystem exists as a
+wrapper around the cgroup filesystem.
+
+The command
+
+mount -t cpuset X /dev/cpuset
+
+is equivalent to
+
+mount -t cgroup -ocpuset X /dev/cpuset
+echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent
+
 2.2 Adding/removing cpus
 ------------------------
 
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 0e9a9aa9df6..fbff900fd5a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2131,7 +2131,7 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_SCHEDSTATS
 	INF("schedstat",  S_IRUGO, pid_schedstat),
 #endif
-#ifdef CONFIG_CPUSETS
+#ifdef CONFIG_PROC_PID_CPUSET
 	REG("cpuset",     S_IRUGO, cpuset),
 #endif
 #ifdef CONFIG_CGROUPS
@@ -2420,7 +2420,7 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_SCHEDSTATS
 	INF("schedstat", S_IRUGO, pid_schedstat),
 #endif
-#ifdef CONFIG_CPUSETS
+#ifdef CONFIG_PROC_PID_CPUSET
 	REG("cpuset",    S_IRUGO, cpuset),
 #endif
 #ifdef CONFIG_CGROUPS
diff --git a/include/linux/cgroup_subsys.h b/include/linux/cgroup_subsys.h
index f8eddbbcad9..b152b51a436 100644
--- a/include/linux/cgroup_subsys.h
+++ b/include/linux/cgroup_subsys.h
@@ -7,4 +7,10 @@
 
 /* */
 
+#ifdef CONFIG_CPUSETS
+SUBSYS(cpuset)
+#endif
+
+/* */
+
 /* */
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index ea44d2e768a..31adfde1c95 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -11,6 +11,7 @@
 #include <linux/sched.h>
 #include <linux/cpumask.h>
 #include <linux/nodemask.h>
+#include <linux/cgroup.h>
 
 #ifdef CONFIG_CPUSETS
 
@@ -19,8 +20,6 @@ extern int number_of_cpusets;	/* How many cpusets are defined in system? */
 extern int cpuset_init_early(void);
 extern int cpuset_init(void);
 extern void cpuset_init_smp(void);
-extern void cpuset_fork(struct task_struct *p);
-extern void cpuset_exit(struct task_struct *p);
 extern cpumask_t cpuset_cpus_allowed(struct task_struct *p);
 extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
 #define cpuset_current_mems_allowed (current->mems_allowed)
@@ -76,13 +75,13 @@ static inline int cpuset_do_slab_mem_spread(void)
 
 extern void cpuset_track_online_nodes(void);
 
+extern int current_cpuset_is_being_rebound(void);
+
 #else /* !CONFIG_CPUSETS */
 
 static inline int cpuset_init_early(void) { return 0; }
 static inline int cpuset_init(void) { return 0; }
 static inline void cpuset_init_smp(void) {}
-static inline void cpuset_fork(struct task_struct *p) {}
-static inline void cpuset_exit(struct task_struct *p) {}
 
 static inline cpumask_t cpuset_cpus_allowed(struct task_struct *p)
 {
@@ -148,6 +147,11 @@ static inline int cpuset_do_slab_mem_spread(void)
 
 static inline void cpuset_track_online_nodes(void) {}
 
+static inline int current_cpuset_is_being_rebound(void)
+{
+	return 0;
+}
+
 #endif /* !CONFIG_CPUSETS */
 
 #endif /* _LINUX_CPUSET_H */
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 38c04d61ee0..59c4865bc85 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -148,14 +148,6 @@ extern void mpol_rebind_task(struct task_struct *tsk,
 					const nodemask_t *new);
 extern void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new);
 extern void mpol_fix_fork_child_flag(struct task_struct *p);
-#define set_cpuset_being_rebound(x) (cpuset_being_rebound = (x))
-
-#ifdef CONFIG_CPUSETS
-#define current_cpuset_is_being_rebound() \
-				(cpuset_being_rebound == current->cpuset)
-#else
-#define current_cpuset_is_being_rebound() 0
-#endif
 
 extern struct mempolicy default_policy;
 extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
@@ -173,8 +165,6 @@ static inline void check_highest_zone(enum zone_type k)
 int do_migrate_pages(struct mm_struct *mm,
 	const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags);
 
-extern void *cpuset_being_rebound;	/* Trigger mpol_copy vma rebind */
-
 #else
 
 struct mempolicy {};
@@ -248,8 +238,6 @@ static inline void mpol_fix_fork_child_flag(struct task_struct *p)
 {
 }
 
-#define set_cpuset_being_rebound(x) do {} while (0)
-
 static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma,
  		unsigned long addr, gfp_t gfp_flags, struct mempolicy **mpol)
 {
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1aa1cfa63b3..93a55f2e5ef 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -756,8 +756,6 @@ static inline int above_background_load(void)
 }
 
 struct io_context;			/* See blkdev.h */
-struct cpuset;
-
 #define NGROUPS_SMALL		32
 #define NGROUPS_PER_BLOCK	((int)(PAGE_SIZE / sizeof(gid_t)))
 struct group_info {
@@ -1125,7 +1123,6 @@ struct task_struct {
 	short il_next;
 #endif
 #ifdef CONFIG_CPUSETS
-	struct cpuset *cpuset;
 	nodemask_t mems_allowed;
 	int cpuset_mems_generation;
 	int cpuset_mem_spread_rotor;
diff --git a/init/Kconfig b/init/Kconfig
index 51b3d14f44f..18b1abc677d 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -280,7 +280,7 @@ config CGROUPS
 
 config CPUSETS
 	bool "Cpuset support"
-	depends on SMP
+	depends on SMP && CGROUPS
 	help
 	  This option will let you create and manage CPUSETs which
 	  allow dynamically partitioning a system into sets of CPUs and
@@ -330,6 +330,11 @@ config SYSFS_DEPRECATED
 	  If you are using a distro that was released in 2006 or later,
 	  it should be safe to say N here.
 
+config PROC_PID_CPUSET
+	bool "Include legacy /proc/<pid>/cpuset file"
+	depends on CPUSETS
+	default y
+
 config RELAY
 	bool "Kernel->user space relay support (formerly relayfs)"
 	help
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index a40a2c4384b..1133062395e 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -5,6 +5,7 @@
  *
  *  Copyright (C) 2003 BULL SA.
  *  Copyright (C) 2004-2006 Silicon Graphics, Inc.
+ *  Copyright (C) 2006 Google, Inc
  *
  *  Portions derived from Patrick Mochel's sysfs code.
  *  sysfs is Copyright (c) 2001-3 Patrick Mochel
@@ -12,6 +13,7 @@
  *  2003-10-10 Written by Simon Derr.
  *  2003-10-22 Updates by Stephen Hemminger.
  *  2004 May-July Rework by Paul Jackson.
+ *  2006 Rework by Paul Menage to use generic cgroups
  *
  *  This file is subject to the terms and conditions of the GNU General Public
  *  License.  See the file COPYING in the main directory of the Linux
@@ -53,8 +55,6 @@
 #include <asm/atomic.h>
 #include <linux/mutex.h>
 
-#define CPUSET_SUPER_MAGIC		0x27e0eb
-
 /*
  * Tracks how many cpusets are currently defined in system.
  * When there is only one cpuset (the root cpuset) we can
@@ -62,6 +62,10 @@
  */
 int number_of_cpusets __read_mostly;
 
+/* Retrieve the cpuset from a cgroup */
+struct cgroup_subsys cpuset_subsys;
+struct cpuset;
+
 /* See "Frequency meter" comments, below. */
 
 struct fmeter {
@@ -72,24 +76,13 @@ struct fmeter {
 };
 
 struct cpuset {
+	struct cgroup_subsys_state css;
+
 	unsigned long flags;		/* "unsigned long" so bitops work */
 	cpumask_t cpus_allowed;		/* CPUs allowed to tasks in cpuset */
 	nodemask_t mems_allowed;	/* Memory Nodes allowed to tasks */
 
-	/*
-	 * Count is atomic so can incr (fork) or decr (exit) without a lock.
-	 */
-	atomic_t count;			/* count tasks using this cpuset */
-
-	/*
-	 * We link our 'sibling' struct into our parents 'children'.
-	 * Our children link their 'sibling' into our 'children'.
-	 */
-	struct list_head sibling;	/* my parents children */
-	struct list_head children;	/* my children */
-
 	struct cpuset *parent;		/* my parent */
-	struct dentry *dentry;		/* cpuset fs entry */
 
 	/*
 	 * Copy of global cpuset_mems_generation as of the most
@@ -100,13 +93,26 @@ struct cpuset {
 	struct fmeter fmeter;		/* memory_pressure filter */
 };
 
+/* Retrieve the cpuset for a cgroup */
+static inline struct cpuset *cgroup_cs(struct cgroup *cont)
+{
+	return container_of(cgroup_subsys_state(cont, cpuset_subsys_id),
+			    struct cpuset, css);
+}
+
+/* Retrieve the cpuset for a task */
+static inline struct cpuset *task_cs(struct task_struct *task)
+{
+	return container_of(task_subsys_state(task, cpuset_subsys_id),
+			    struct cpuset, css);
+}
+
+
 /* bits in struct cpuset flags field */
 typedef enum {
 	CS_CPU_EXCLUSIVE,
 	CS_MEM_EXCLUSIVE,
 	CS_MEMORY_MIGRATE,
-	CS_REMOVED,
-	CS_NOTIFY_ON_RELEASE,
 	CS_SPREAD_PAGE,
 	CS_SPREAD_SLAB,
 } cpuset_flagbits_t;
@@ -122,16 +128,6 @@ static inline int is_mem_exclusive(const struct cpuset *cs)
 	return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
 }
 
-static inline int is_removed(const struct cpuset *cs)
-{
-	return test_bit(CS_REMOVED, &cs->flags);
-}
-
-static inline int notify_on_release(const struct cpuset *cs)
-{
-	return test_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
-}
-
 static inline int is_memory_migrate(const struct cpuset *cs)
 {
 	return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
@@ -172,14 +168,8 @@ static struct cpuset top_cpuset = {
 	.flags = ((1 << CS_CPU_EXCLUSIVE) | (1 << CS_MEM_EXCLUSIVE)),
 	.cpus_allowed = CPU_MASK_ALL,
 	.mems_allowed = NODE_MASK_ALL,
-	.count = ATOMIC_INIT(0),
-	.sibling = LIST_HEAD_INIT(top_cpuset.sibling),
-	.children = LIST_HEAD_INIT(top_cpuset.children),
 };
 
-static struct vfsmount *cpuset_mount;
-static struct super_block *cpuset_sb;
-
 /*
  * We have two global cpuset mutexes below.  They can nest.
  * It is ok to first take manage_mutex, then nest callback_mutex.  We also
@@ -263,297 +253,33 @@ static struct super_block *cpuset_sb;
  * the routine cpuset_update_task_memory_state().
  */
 
-static DEFINE_MUTEX(manage_mutex);
 static DEFINE_MUTEX(callback_mutex);
 
-/*
- * A couple of forward declarations required, due to cyclic reference loop:
- *  cpuset_mkdir -> cpuset_create -> cpuset_populate_dir -> cpuset_add_file
- *  -> cpuset_create_file -> cpuset_dir_inode_operations -> cpuset_mkdir.
- */
-
-static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode);
-static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry);
-
-static struct backing_dev_info cpuset_backing_dev_info = {
-	.ra_pages = 0,		/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
-};
-
-static struct inode *cpuset_new_inode(mode_t mode)
-{
-	struct inode *inode = new_inode(cpuset_sb);
-
-	if (inode) {
-		inode->i_mode = mode;
-		inode->i_uid = current->fsuid;
-		inode->i_gid = current->fsgid;
-		inode->i_blocks = 0;
-		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-		inode->i_mapping->backing_dev_info = &cpuset_backing_dev_info;
-	}
-	return inode;
-}
-
-static void cpuset_diput(struct dentry *dentry, struct inode *inode)
-{
-	/* is dentry a directory ? if so, kfree() associated cpuset */
-	if (S_ISDIR(inode->i_mode)) {
-		struct cpuset *cs = dentry->d_fsdata;
-		BUG_ON(!(is_removed(cs)));
-		kfree(cs);
-	}
-	iput(inode);
-}
-
-static struct dentry_operations cpuset_dops = {
-	.d_iput = cpuset_diput,
-};
-
-static struct dentry *cpuset_get_dentry(struct dentry *parent, const char *name)
-{
-	struct dentry *d = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(d))
-		d->d_op = &cpuset_dops;
-	return d;
-}
-
-static void remove_dir(struct dentry *d)
-{
-	struct dentry *parent = dget(d->d_parent);
-
-	d_delete(d);
-	simple_rmdir(parent->d_inode, d);
-	dput(parent);
-}
-
-/*
- * NOTE : the dentry must have been dget()'ed
- */
-static void cpuset_d_remove_dir(struct dentry *dentry)
-{
-	struct list_head *node;
-
-	spin_lock(&dcache_lock);
-	node = dentry->d_subdirs.next;
-	while (node != &dentry->d_subdirs) {
-		struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
-		list_del_init(node);
-		if (d->d_inode) {
-			d = dget_locked(d);
-			spin_unlock(&dcache_lock);
-			d_delete(d);
-			simple_unlink(dentry->d_inode, d);
-			dput(d);
-			spin_lock(&dcache_lock);
-		}
-		node = dentry->d_subdirs.next;
-	}
-	list_del_init(&dentry->d_u.d_child);
-	spin_unlock(&dcache_lock);
-	remove_dir(dentry);
-}
-
-static struct super_operations cpuset_ops = {
-	.statfs = simple_statfs,
-	.drop_inode = generic_delete_inode,
-};
-
-static int cpuset_fill_super(struct super_block *sb, void *unused_data,
-							int unused_silent)
-{
-	struct inode *inode;
-	struct dentry *root;
-
-	sb->s_blocksize = PAGE_CACHE_SIZE;
-	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
-	sb->s_magic = CPUSET_SUPER_MAGIC;
-	sb->s_op = &cpuset_ops;
-	cpuset_sb = sb;
-
-	inode = cpuset_new_inode(S_IFDIR | S_IRUGO | S_IXUGO | S_IWUSR);
-	if (inode) {
-		inode->i_op = &simple_dir_inode_operations;
-		inode->i_fop = &simple_dir_operations;
-		/* directories start off with i_nlink == 2 (for "." entry) */
-		inc_nlink(inode);
-	} else {
-		return -ENOMEM;
-	}
-
-	root = d_alloc_root(inode);
-	if (!root) {
-		iput(inode);
-		return -ENOMEM;
-	}
-	sb->s_root = root;
-	return 0;
-}
-
+/* This is ugly, but preserves the userspace API for existing cpuset
+ * users. If someone tries to mount the "cpuset" filesystem, we
+ * silently switch it to mount "cgroup" instead */
 static int cpuset_get_sb(struct file_system_type *fs_type,
 			 int flags, const char *unused_dev_name,
 			 void *data, struct vfsmount *mnt)
 {
-	return get_sb_single(fs_type, flags, data, cpuset_fill_super, mnt);
+	struct file_system_type *cgroup_fs = get_fs_type("cgroup");
+	int ret = -ENODEV;
+	if (cgroup_fs) {
+		char mountopts[] =
+			"cpuset,noprefix,"
+			"release_agent=/sbin/cpuset_release_agent";
+		ret = cgroup_fs->get_sb(cgroup_fs, flags,
+					   unused_dev_name, mountopts, mnt);
+		put_filesystem(cgroup_fs);
+	}
+	return ret;
 }
 
 static struct file_system_type cpuset_fs_type = {
 	.name = "cpuset",
 	.get_sb = cpuset_get_sb,
-	.kill_sb = kill_litter_super,
 };
 
-/* struct cftype:
- *
- * The files in the cpuset filesystem mostly have a very simple read/write
- * handling, some common function will take care of it. Nevertheless some cases
- * (read tasks) are special and therefore I define this structure for every
- * kind of file.
- *
- *
- * When reading/writing to a file:
- *	- the cpuset to use in file->f_path.dentry->d_parent->d_fsdata
- *	- the 'cftype' of the file is file->f_path.dentry->d_fsdata
- */
-
-struct cftype {
-	char *name;
-	int private;
-	int (*open) (struct inode *inode, struct file *file);
-	ssize_t (*read) (struct file *file, char __user *buf, size_t nbytes,
-							loff_t *ppos);
-	int (*write) (struct file *file, const char __user *buf, size_t nbytes,
-							loff_t *ppos);
-	int (*release) (struct inode *inode, struct file *file);
-};
-
-static inline struct cpuset *__d_cs(struct dentry *dentry)
-{
-	return dentry->d_fsdata;
-}
-
-static inline struct cftype *__d_cft(struct dentry *dentry)
-{
-	return dentry->d_fsdata;
-}
-
-/*
- * Call with manage_mutex held.  Writes path of cpuset into buf.
- * Returns 0 on success, -errno on error.
- */
-
-static int cpuset_path(const struct cpuset *cs, char *buf, int buflen)
-{
-	char *start;
-
-	start = buf + buflen;
-
-	*--start = '\0';
-	for (;;) {
-		int len = cs->dentry->d_name.len;
-		if ((start -= len) < buf)
-			return -ENAMETOOLONG;
-		memcpy(start, cs->dentry->d_name.name, len);
-		cs = cs->parent;
-		if (!cs)
-			break;
-		if (!cs->parent)
-			continue;
-		if (--start < buf)
-			return -ENAMETOOLONG;
-		*start = '/';
-	}
-	memmove(buf, start, buf + buflen - start);
-	return 0;
-}
-
-/*
- * Notify userspace when a cpuset is released, by running
- * /sbin/cpuset_release_agent with the name of the cpuset (path
- * relative to the root of cpuset file system) as the argument.
- *
- * Most likely, this user command will try to rmdir this cpuset.
- *
- * This races with the possibility that some other task will be
- * attached to this cpuset before it is removed, or that some other
- * user task will 'mkdir' a child cpuset of this cpuset.  That's ok.
- * The presumed 'rmdir' will fail quietly if this cpuset is no longer
- * unused, and this cpuset will be reprieved from its death sentence,
- * to continue to serve a useful existence.  Next time it's released,
- * we will get notified again, if it still has 'notify_on_release' set.
- *
- * The final arg to call_usermodehelper() is 0, which means don't
- * wait.  The separate /sbin/cpuset_release_agent task is forked by
- * call_usermodehelper(), then control in this thread returns here,
- * without waiting for the release agent task.  We don't bother to
- * wait because the caller of this routine has no use for the exit
- * status of the /sbin/cpuset_release_agent task, so no sense holding
- * our caller up for that.
- *
- * When we had only one cpuset mutex, we had to call this
- * without holding it, to avoid deadlock when call_usermodehelper()
- * allocated memory.  With two locks, we could now call this while
- * holding manage_mutex, but we still don't, so as to minimize
- * the time manage_mutex is held.
- */
-
-static void cpuset_release_agent(const char *pathbuf)
-{
-	char *argv[3], *envp[3];
-	int i;
-
-	if (!pathbuf)
-		return;
-
-	i = 0;
-	argv[i++] = "/sbin/cpuset_release_agent";
-	argv[i++] = (char *)pathbuf;
-	argv[i] = NULL;
-
-	i = 0;
-	/* minimal command environment */
-	envp[i++] = "HOME=/";
-	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
-	envp[i] = NULL;
-
-	call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
-	kfree(pathbuf);
-}
-
-/*
- * Either cs->count of using tasks transitioned to zero, or the
- * cs->children list of child cpusets just became empty.  If this
- * cs is notify_on_release() and now both the user count is zero and
- * the list of children is empty, prepare cpuset path in a kmalloc'd
- * buffer, to be returned via ppathbuf, so that the caller can invoke
- * cpuset_release_agent() with it later on, once manage_mutex is dropped.
- * Call here with manage_mutex held.
- *
- * This check_for_release() routine is responsible for kmalloc'ing
- * pathbuf.  The above cpuset_release_agent() is responsible for
- * kfree'ing pathbuf.  The caller of these routines is responsible
- * for providing a pathbuf pointer, initialized to NULL, then
- * calling check_for_release() with manage_mutex held and the address
- * of the pathbuf pointer, then dropping manage_mutex, then calling
- * cpuset_release_agent() with pathbuf, as set by check_for_release().
- */
-
-static void check_for_release(struct cpuset *cs, char **ppathbuf)
-{
-	if (notify_on_release(cs) && atomic_read(&cs->count) == 0 &&
-	    list_empty(&cs->children)) {
-		char *buf;
-
-		buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-		if (!buf)
-			return;
-		if (cpuset_path(cs, buf, PAGE_SIZE) < 0)
-			kfree(buf);
-		else
-			*ppathbuf = buf;
-	}
-}
-
 /*
  * Return in *pmask the portion of a cpusets's cpus_allowed that
  * are online.  If none are online, walk up the cpuset hierarchy
@@ -653,20 +379,19 @@ void cpuset_update_task_memory_state(void)
 	struct task_struct *tsk = current;
 	struct cpuset *cs;
 
-	if (tsk->cpuset == &top_cpuset) {
+	if (task_cs(tsk) == &top_cpuset) {
 		/* Don't need rcu for top_cpuset.  It's never freed. */
 		my_cpusets_mem_gen = top_cpuset.mems_generation;
 	} else {
 		rcu_read_lock();
-		cs = rcu_dereference(tsk->cpuset);
-		my_cpusets_mem_gen = cs->mems_generation;
+		my_cpusets_mem_gen = task_cs(current)->mems_generation;
 		rcu_read_unlock();
 	}
 
 	if (my_cpusets_mem_gen != tsk->cpuset_mems_generation) {
 		mutex_lock(&callback_mutex);
 		task_lock(tsk);
-		cs = tsk->cpuset;	/* Maybe changed when task not locked */
+		cs = task_cs(tsk); /* Maybe changed when task not locked */
 		guarantee_online_mems(cs, &tsk->mems_allowed);
 		tsk->cpuset_mems_generation = cs->mems_generation;
 		if (is_spread_page(cs))
@@ -721,11 +446,12 @@ static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
 
 static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
 {
+	struct cgroup *cont;
 	struct cpuset *c, *par;
 
 	/* Each of our child cpusets must be a subset of us */
-	list_for_each_entry(c, &cur->children, sibling) {
-		if (!is_cpuset_subset(c, trial))
+	list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
+		if (!is_cpuset_subset(cgroup_cs(cont), trial))
 			return -EBUSY;
 	}
 
@@ -740,7 +466,8 @@ static int validate_change(const struct cpuset *cur, const struct cpuset *trial)
 		return -EACCES;
 
 	/* If either I or some sibling (!= me) is exclusive, we can't overlap */
-	list_for_each_entry(c, &par->children, sibling) {
+	list_for_each_entry(cont, &par->css.cgroup->children, sibling) {
+		c = cgroup_cs(cont);
 		if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
 		    c != cur &&
 		    cpus_intersects(trial->cpus_allowed, c->cpus_allowed))
@@ -783,7 +510,8 @@ static int update_cpumask(struct cpuset *cs, char *buf)
 	}
 	cpus_and(trialcs.cpus_allowed, trialcs.cpus_allowed, cpu_online_map);
 	/* cpus_allowed cannot be empty for a cpuset with attached tasks. */
-	if (atomic_read(&cs->count) && cpus_empty(trialcs.cpus_allowed))
+	if (cgroup_task_count(cs->css.cgroup) &&
+	    cpus_empty(trialcs.cpus_allowed))
 		return -ENOSPC;
 	retval = validate_change(cs, &trialcs);
 	if (retval < 0)
@@ -839,7 +567,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
 	do_migrate_pages(mm, from, to, MPOL_MF_MOVE_ALL);
 
 	mutex_lock(&callback_mutex);
-	guarantee_online_mems(tsk->cpuset, &tsk->mems_allowed);
+	guarantee_online_mems(task_cs(tsk),&tsk->mems_allowed);
 	mutex_unlock(&callback_mutex);
 }
 
@@ -857,16 +585,19 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
  * their mempolicies to the cpusets new mems_allowed.
  */
 
+static void *cpuset_being_rebound;
+
 static int update_nodemask(struct cpuset *cs, char *buf)
 {
 	struct cpuset trialcs;
 	nodemask_t oldmem;
-	struct task_struct *g, *p;
+	struct task_struct *p;
 	struct mm_struct **mmarray;
 	int i, n, ntasks;
 	int migrate;
 	int fudge;
 	int retval;
+	struct cgroup_iter it;
 
 	/*
 	 * top_cpuset.mems_allowed tracks node_stats[N_HIGH_MEMORY];
@@ -909,7 +640,8 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 		goto done;
 	}
 	/* mems_allowed cannot be empty for a cpuset with attached tasks. */
-	if (atomic_read(&cs->count) && nodes_empty(trialcs.mems_allowed)) {
+	if (cgroup_task_count(cs->css.cgroup) &&
+	    nodes_empty(trialcs.mems_allowed)) {
 		retval = -ENOSPC;
 		goto done;
 	}
@@ -922,7 +654,7 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 	cs->mems_generation = cpuset_mems_generation++;
 	mutex_unlock(&callback_mutex);
 
-	set_cpuset_being_rebound(cs);		/* causes mpol_copy() rebind */
+	cpuset_being_rebound = cs;		/* causes mpol_copy() rebind */
 
 	fudge = 10;				/* spare mmarray[] slots */
 	fudge += cpus_weight(cs->cpus_allowed);	/* imagine one fork-bomb/cpu */
@@ -936,13 +668,13 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 	 * enough mmarray[] w/o using GFP_ATOMIC.
 	 */
 	while (1) {
-		ntasks = atomic_read(&cs->count);	/* guess */
+		ntasks = cgroup_task_count(cs->css.cgroup);  /* guess */
 		ntasks += fudge;
 		mmarray = kmalloc(ntasks * sizeof(*mmarray), GFP_KERNEL);
 		if (!mmarray)
 			goto done;
 		read_lock(&tasklist_lock);		/* block fork */
-		if (atomic_read(&cs->count) <= ntasks)
+		if (cgroup_task_count(cs->css.cgroup) <= ntasks)
 			break;				/* got enough */
 		read_unlock(&tasklist_lock);		/* try again */
 		kfree(mmarray);
@@ -951,21 +683,21 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 	n = 0;
 
 	/* Load up mmarray[] with mm reference for each task in cpuset. */
-	do_each_thread(g, p) {
+	cgroup_iter_start(cs->css.cgroup, &it);
+	while ((p = cgroup_iter_next(cs->css.cgroup, &it))) {
 		struct mm_struct *mm;
 
 		if (n >= ntasks) {
 			printk(KERN_WARNING
 				"Cpuset mempolicy rebind incomplete.\n");
-			continue;
+			break;
 		}
-		if (p->cpuset != cs)
-			continue;
 		mm = get_task_mm(p);
 		if (!mm)
 			continue;
 		mmarray[n++] = mm;
-	} while_each_thread(g, p);
+	}
+	cgroup_iter_end(cs->css.cgroup, &it);
 	read_unlock(&tasklist_lock);
 
 	/*
@@ -993,12 +725,17 @@ static int update_nodemask(struct cpuset *cs, char *buf)
 
 	/* We're done rebinding vma's to this cpusets new mems_allowed. */
 	kfree(mmarray);
-	set_cpuset_being_rebound(NULL);
+	cpuset_being_rebound = NULL;
 	retval = 0;
 done:
 	return retval;
 }
 
+int current_cpuset_is_being_rebound(void)
+{
+	return task_cs(current) == cpuset_being_rebound;
+}
+
 /*
  * Call with manage_mutex held.
  */
@@ -1145,85 +882,34 @@ static int fmeter_getrate(struct fmeter *fmp)
 	return val;
 }
 
-/*
- * Attack task specified by pid in 'pidbuf' to cpuset 'cs', possibly
- * writing the path of the old cpuset in 'ppathbuf' if it needs to be
- * notified on release.
- *
- * Call holding manage_mutex.  May take callback_mutex and task_lock of
- * the task 'pid' during call.
- */
-
-static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
+static int cpuset_can_attach(struct cgroup_subsys *ss,
+			     struct cgroup *cont, struct task_struct *tsk)
 {
-	pid_t pid;
-	struct task_struct *tsk;
-	struct cpuset *oldcs;
-	cpumask_t cpus;
-	nodemask_t from, to;
-	struct mm_struct *mm;
-	int retval;
+	struct cpuset *cs = cgroup_cs(cont);
 
-	if (sscanf(pidbuf, "%d", &pid) != 1)
-		return -EIO;
 	if (cpus_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
 		return -ENOSPC;
 
-	if (pid) {
-		read_lock(&tasklist_lock);
-
-		tsk = find_task_by_pid(pid);
-		if (!tsk || tsk->flags & PF_EXITING) {
-			read_unlock(&tasklist_lock);
-			return -ESRCH;
-		}
-
-		get_task_struct(tsk);
-		read_unlock(&tasklist_lock);
-
-		if ((current->euid) && (current->euid != tsk->uid)
-		    && (current->euid != tsk->suid)) {
-			put_task_struct(tsk);
-			return -EACCES;
-		}
-	} else {
-		tsk = current;
-		get_task_struct(tsk);
-	}
+	return security_task_setscheduler(tsk, 0, NULL);
+}
 
-	retval = security_task_setscheduler(tsk, 0, NULL);
-	if (retval) {
-		put_task_struct(tsk);
-		return retval;
-	}
+static void cpuset_attach(struct cgroup_subsys *ss,
+			  struct cgroup *cont, struct cgroup *oldcont,
+			  struct task_struct *tsk)
+{
+	cpumask_t cpus;
+	nodemask_t from, to;
+	struct mm_struct *mm;
+	struct cpuset *cs = cgroup_cs(cont);
+	struct cpuset *oldcs = cgroup_cs(oldcont);
 
 	mutex_lock(&callback_mutex);
-
-	task_lock(tsk);
-	oldcs = tsk->cpuset;
-	/*
-	 * After getting 'oldcs' cpuset ptr, be sure still not exiting.
-	 * If 'oldcs' might be the top_cpuset due to the_top_cpuset_hack
-	 * then fail this attach_task(), to avoid breaking top_cpuset.count.
-	 */
-	if (tsk->flags & PF_EXITING) {
-		task_unlock(tsk);
-		mutex_unlock(&callback_mutex);
-		put_task_struct(tsk);
-		return -ESRCH;
-	}
-	atomic_inc(&cs->count);
-	rcu_assign_pointer(tsk->cpuset, cs);
-	task_unlock(tsk);
-
 	guarantee_online_cpus(cs, &cpus);
 	set_cpus_allowed(tsk, cpus);
+	mutex_unlock(&callback_mutex);
 
 	from = oldcs->mems_allowed;
 	to = cs->mems_allowed;
-
-	mutex_unlock(&callback_mutex);
-
 	mm = get_task_mm(tsk);
 	if (mm) {
 		mpol_rebind_mm(mm, &to);
@@ -1232,40 +918,31 @@ static int attach_task(struct cpuset *cs, char *pidbuf, char **ppathbuf)
 		mmput(mm);
 	}
 
-	put_task_struct(tsk);
-	synchronize_rcu();
-	if (atomic_dec_and_test(&oldcs->count))
-		check_for_release(oldcs, ppathbuf);
-	return 0;
 }
 
 /* The various types of files and directories in a cpuset file system */
 
 typedef enum {
-	FILE_ROOT,
-	FILE_DIR,
 	FILE_MEMORY_MIGRATE,
 	FILE_CPULIST,
 	FILE_MEMLIST,
 	FILE_CPU_EXCLUSIVE,
 	FILE_MEM_EXCLUSIVE,
-	FILE_NOTIFY_ON_RELEASE,
 	FILE_MEMORY_PRESSURE_ENABLED,
 	FILE_MEMORY_PRESSURE,
 	FILE_SPREAD_PAGE,
 	FILE_SPREAD_SLAB,
-	FILE_TASKLIST,
 } cpuset_filetype_t;
 
-static ssize_t cpuset_common_file_write(struct file *file,
+static ssize_t cpuset_common_file_write(struct cgroup *cont,
+					struct cftype *cft,
+					struct file *file,
 					const char __user *userbuf,
 					size_t nbytes, loff_t *unused_ppos)
 {
-	struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
-	struct cftype *cft = __d_cft(file->f_path.dentry);
+	struct cpuset *cs = cgroup_cs(cont);
 	cpuset_filetype_t type = cft->private;
 	char *buffer;
-	char *pathbuf = NULL;
 	int retval = 0;
 
 	/* Crude upper limit on largest legitimate cpulist user might write. */
@@ -1282,9 +959,9 @@ static ssize_t cpuset_common_file_write(struct file *file,
 	}
 	buffer[nbytes] = 0;	/* nul-terminate */
 
-	mutex_lock(&manage_mutex);
+	cgroup_lock();
 
-	if (is_removed(cs)) {
+	if (cgroup_is_removed(cont)) {
 		retval = -ENODEV;
 		goto out2;
 	}
@@ -1302,9 +979,6 @@ static ssize_t cpuset_common_file_write(struct file *file,
 	case FILE_MEM_EXCLUSIVE:
 		retval = update_flag(CS_MEM_EXCLUSIVE, cs, buffer);
 		break;
-	case FILE_NOTIFY_ON_RELEASE:
-		retval = update_flag(CS_NOTIFY_ON_RELEASE, cs, buffer);
-		break;
 	case FILE_MEMORY_MIGRATE:
 		retval = update_flag(CS_MEMORY_MIGRATE, cs, buffer);
 		break;
@@ -1322,9 +996,6 @@ static ssize_t cpuset_common_file_write(struct file *file,
 		retval = update_flag(CS_SPREAD_SLAB, cs, buffer);
 		cs->mems_generation = cpuset_mems_generation++;
 		break;
-	case FILE_TASKLIST:
-		retval = attach_task(cs, buffer, &pathbuf);
-		break;
 	default:
 		retval = -EINVAL;
 		goto out2;
@@ -1333,30 +1004,12 @@ static ssize_t cpuset_common_file_write(struct file *file,
 	if (retval == 0)
 		retval = nbytes;
 out2:
-	mutex_unlock(&manage_mutex);
-	cpuset_release_agent(pathbuf);
+	cgroup_unlock();
 out1:
 	kfree(buffer);
 	return retval;
 }
 
-static ssize_t cpuset_file_write(struct file *file, const char __user *buf,
-						size_t nbytes, loff_t *ppos)
-{
-	ssize_t retval = 0;
-	struct cftype *cft = __d_cft(file->f_path.dentry);
-	if (!cft)
-		return -ENODEV;
-
-	/* special function ? */
-	if (cft->write)
-		retval = cft->write(file, buf, nbytes, ppos);
-	else
-		retval = cpuset_common_file_write(file, buf, nbytes, ppos);
-
-	return retval;
-}
-
 /*
  * These ascii lists should be read in a single call, by using a user
  * buffer large enough to hold the entire map.  If read in smaller
@@ -1391,11 +1044,13 @@ static int cpuset_sprintf_memlist(char *page, struct cpuset *cs)
 	return nodelist_scnprintf(page, PAGE_SIZE, mask);
 }
 
-static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
-				size_t nbytes, loff_t *ppos)
+static ssize_t cpuset_common_file_read(struct cgroup *cont,
+				       struct cftype *cft,
+				       struct file *file,
+				       char __user *buf,
+				       size_t nbytes, loff_t *ppos)
 {
-	struct cftype *cft = __d_cft(file->f_path.dentry);
-	struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
+	struct cpuset *cs = cgroup_cs(cont);
 	cpuset_filetype_t type = cft->private;
 	char *page;
 	ssize_t retval = 0;
@@ -1419,9 +1074,6 @@ static ssize_t cpuset_common_file_read(struct file *file, char __user *buf,
 	case FILE_MEM_EXCLUSIVE:
 		*s++ = is_mem_exclusive(cs) ? '1' : '0';
 		break;
-	case FILE_NOTIFY_ON_RELEASE:
-		*s++ = notify_on_release(cs) ? '1' : '0';
-		break;
 	case FILE_MEMORY_MIGRATE:
 		*s++ = is_memory_migrate(cs) ? '1' : '0';
 		break;
@@ -1449,390 +1101,141 @@ out:
 	return retval;
 }
 
-static ssize_t cpuset_file_read(struct file *file, char __user *buf, size_t nbytes,
-								loff_t *ppos)
-{
-	ssize_t retval = 0;
-	struct cftype *cft = __d_cft(file->f_path.dentry);
-	if (!cft)
-		return -ENODEV;
 
-	/* special function ? */
-	if (cft->read)
-		retval = cft->read(file, buf, nbytes, ppos);
-	else
-		retval = cpuset_common_file_read(file, buf, nbytes, ppos);
 
-	return retval;
-}
 
-static int cpuset_file_open(struct inode *inode, struct file *file)
-{
-	int err;
-	struct cftype *cft;
-
-	err = generic_file_open(inode, file);
-	if (err)
-		return err;
-
-	cft = __d_cft(file->f_path.dentry);
-	if (!cft)
-		return -ENODEV;
-	if (cft->open)
-		err = cft->open(inode, file);
-	else
-		err = 0;
-
-	return err;
-}
-
-static int cpuset_file_release(struct inode *inode, struct file *file)
-{
-	struct cftype *cft = __d_cft(file->f_path.dentry);
-	if (cft->release)
-		return cft->release(inode, file);
-	return 0;
-}
-
-/*
- * cpuset_rename - Only allow simple rename of directories in place.
- */
-static int cpuset_rename(struct inode *old_dir, struct dentry *old_dentry,
-                  struct inode *new_dir, struct dentry *new_dentry)
-{
-	if (!S_ISDIR(old_dentry->d_inode->i_mode))
-		return -ENOTDIR;
-	if (new_dentry->d_inode)
-		return -EEXIST;
-	if (old_dir != new_dir)
-		return -EIO;
-	return simple_rename(old_dir, old_dentry, new_dir, new_dentry);
-}
-
-static const struct file_operations cpuset_file_operations = {
-	.read = cpuset_file_read,
-	.write = cpuset_file_write,
-	.llseek = generic_file_llseek,
-	.open = cpuset_file_open,
-	.release = cpuset_file_release,
-};
-
-static const struct inode_operations cpuset_dir_inode_operations = {
-	.lookup = simple_lookup,
-	.mkdir = cpuset_mkdir,
-	.rmdir = cpuset_rmdir,
-	.rename = cpuset_rename,
-};
-
-static int cpuset_create_file(struct dentry *dentry, int mode)
-{
-	struct inode *inode;
-
-	if (!dentry)
-		return -ENOENT;
-	if (dentry->d_inode)
-		return -EEXIST;
-
-	inode = cpuset_new_inode(mode);
-	if (!inode)
-		return -ENOMEM;
-
-	if (S_ISDIR(mode)) {
-		inode->i_op = &cpuset_dir_inode_operations;
-		inode->i_fop = &simple_dir_operations;
-
-		/* start off with i_nlink == 2 (for "." entry) */
-		inc_nlink(inode);
-	} else if (S_ISREG(mode)) {
-		inode->i_size = 0;
-		inode->i_fop = &cpuset_file_operations;
-	}
-
-	d_instantiate(dentry, inode);
-	dget(dentry);	/* Extra count - pin the dentry in core */
-	return 0;
-}
-
-/*
- *	cpuset_create_dir - create a directory for an object.
- *	cs:	the cpuset we create the directory for.
- *		It must have a valid ->parent field
- *		And we are going to fill its ->dentry field.
- *	name:	The name to give to the cpuset directory. Will be copied.
- *	mode:	mode to set on new directory.
- */
-
-static int cpuset_create_dir(struct cpuset *cs, const char *name, int mode)
-{
-	struct dentry *dentry = NULL;
-	struct dentry *parent;
-	int error = 0;
-
-	parent = cs->parent->dentry;
-	dentry = cpuset_get_dentry(parent, name);
-	if (IS_ERR(dentry))
-		return PTR_ERR(dentry);
-	error = cpuset_create_file(dentry, S_IFDIR | mode);
-	if (!error) {
-		dentry->d_fsdata = cs;
-		inc_nlink(parent->d_inode);
-		cs->dentry = dentry;
-	}
-	dput(dentry);
-
-	return error;
-}
-
-static int cpuset_add_file(struct dentry *dir, const struct cftype *cft)
-{
-	struct dentry *dentry;
-	int error;
-
-	mutex_lock(&dir->d_inode->i_mutex);
-	dentry = cpuset_get_dentry(dir, cft->name);
-	if (!IS_ERR(dentry)) {
-		error = cpuset_create_file(dentry, 0644 | S_IFREG);
-		if (!error)
-			dentry->d_fsdata = (void *)cft;
-		dput(dentry);
-	} else
-		error = PTR_ERR(dentry);
-	mutex_unlock(&dir->d_inode->i_mutex);
-	return error;
-}
-
-/*
- * Stuff for reading the 'tasks' file.
- *
- * Reading this file can return large amounts of data if a cpuset has
- * *lots* of attached tasks. So it may need several calls to read(),
- * but we cannot guarantee that the information we produce is correct
- * unless we produce it entirely atomically.
- *
- * Upon tasks file open(), a struct ctr_struct is allocated, that
- * will have a pointer to an array (also allocated here).  The struct
- * ctr_struct * is stored in file->private_data.  Its resources will
- * be freed by release() when the file is closed.  The array is used
- * to sprintf the PIDs and then used by read().
- */
-
-/* cpusets_tasks_read array */
-
-struct ctr_struct {
-	char *buf;
-	int bufsz;
-};
-
-/*
- * Load into 'pidarray' up to 'npids' of the tasks using cpuset 'cs'.
- * Return actual number of pids loaded.  No need to task_lock(p)
- * when reading out p->cpuset, as we don't really care if it changes
- * on the next cycle, and we are not going to try to dereference it.
- */
-static int pid_array_load(pid_t *pidarray, int npids, struct cpuset *cs)
-{
-	int n = 0;
-	struct task_struct *g, *p;
-
-	read_lock(&tasklist_lock);
-
-	do_each_thread(g, p) {
-		if (p->cpuset == cs) {
-			pidarray[n++] = p->pid;
-			if (unlikely(n == npids))
-				goto array_full;
-		}
-	} while_each_thread(g, p);
-
-array_full:
-	read_unlock(&tasklist_lock);
-	return n;
-}
-
-static int cmppid(const void *a, const void *b)
-{
-	return *(pid_t *)a - *(pid_t *)b;
-}
-
-/*
- * Convert array 'a' of 'npids' pid_t's to a string of newline separated
- * decimal pids in 'buf'.  Don't write more than 'sz' chars, but return
- * count 'cnt' of how many chars would be written if buf were large enough.
- */
-static int pid_array_to_buf(char *buf, int sz, pid_t *a, int npids)
-{
-	int cnt = 0;
-	int i;
-
-	for (i = 0; i < npids; i++)
-		cnt += snprintf(buf + cnt, max(sz - cnt, 0), "%d\n", a[i]);
-	return cnt;
-}
-
-/*
- * Handle an open on 'tasks' file.  Prepare a buffer listing the
- * process id's of tasks currently attached to the cpuset being opened.
- *
- * Does not require any specific cpuset mutexes, and does not take any.
- */
-static int cpuset_tasks_open(struct inode *unused, struct file *file)
-{
-	struct cpuset *cs = __d_cs(file->f_path.dentry->d_parent);
-	struct ctr_struct *ctr;
-	pid_t *pidarray;
-	int npids;
-	char c;
-
-	if (!(file->f_mode & FMODE_READ))
-		return 0;
-
-	ctr = kmalloc(sizeof(*ctr), GFP_KERNEL);
-	if (!ctr)
-		goto err0;
-
-	/*
-	 * If cpuset gets more users after we read count, we won't have
-	 * enough space - tough.  This race is indistinguishable to the
-	 * caller from the case that the additional cpuset users didn't
-	 * show up until sometime later on.
-	 */
-	npids = atomic_read(&cs->count);
-	pidarray = kmalloc(npids * sizeof(pid_t), GFP_KERNEL);
-	if (!pidarray)
-		goto err1;
-
-	npids = pid_array_load(pidarray, npids, cs);
-	sort(pidarray, npids, sizeof(pid_t), cmppid, NULL);
-
-	/* Call pid_array_to_buf() twice, first just to get bufsz */
-	ctr->bufsz = pid_array_to_buf(&c, sizeof(c), pidarray, npids) + 1;
-	ctr->buf = kmalloc(ctr->bufsz, GFP_KERNEL);
-	if (!ctr->buf)
-		goto err2;
-	ctr->bufsz = pid_array_to_buf(ctr->buf, ctr->bufsz, pidarray, npids);
-
-	kfree(pidarray);
-	file->private_data = ctr;
-	return 0;
-
-err2:
-	kfree(pidarray);
-err1:
-	kfree(ctr);
-err0:
-	return -ENOMEM;
-}
-
-static ssize_t cpuset_tasks_read(struct file *file, char __user *buf,
-						size_t nbytes, loff_t *ppos)
-{
-	struct ctr_struct *ctr = file->private_data;
-
-	return simple_read_from_buffer(buf, nbytes, ppos, ctr->buf, ctr->bufsz);
-}
-
-static int cpuset_tasks_release(struct inode *unused_inode, struct file *file)
-{
-	struct ctr_struct *ctr;
-
-	if (file->f_mode & FMODE_READ) {
-		ctr = file->private_data;
-		kfree(ctr->buf);
-		kfree(ctr);
-	}
-	return 0;
-}
 
 /*
  * for the common functions, 'private' gives the type of file
  */
 
-static struct cftype cft_tasks = {
-	.name = "tasks",
-	.open = cpuset_tasks_open,
-	.read = cpuset_tasks_read,
-	.release = cpuset_tasks_release,
-	.private = FILE_TASKLIST,
-};
-
 static struct cftype cft_cpus = {
 	.name = "cpus",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_CPULIST,
 };
 
 static struct cftype cft_mems = {
 	.name = "mems",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_MEMLIST,
 };
 
 static struct cftype cft_cpu_exclusive = {
 	.name = "cpu_exclusive",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_CPU_EXCLUSIVE,
 };
 
 static struct cftype cft_mem_exclusive = {
 	.name = "mem_exclusive",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_MEM_EXCLUSIVE,
 };
 
-static struct cftype cft_notify_on_release = {
-	.name = "notify_on_release",
-	.private = FILE_NOTIFY_ON_RELEASE,
-};
-
 static struct cftype cft_memory_migrate = {
 	.name = "memory_migrate",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_MEMORY_MIGRATE,
 };
 
 static struct cftype cft_memory_pressure_enabled = {
 	.name = "memory_pressure_enabled",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_MEMORY_PRESSURE_ENABLED,
 };
 
 static struct cftype cft_memory_pressure = {
 	.name = "memory_pressure",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_MEMORY_PRESSURE,
 };
 
 static struct cftype cft_spread_page = {
 	.name = "memory_spread_page",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_SPREAD_PAGE,
 };
 
 static struct cftype cft_spread_slab = {
 	.name = "memory_spread_slab",
+	.read = cpuset_common_file_read,
+	.write = cpuset_common_file_write,
 	.private = FILE_SPREAD_SLAB,
 };
 
-static int cpuset_populate_dir(struct dentry *cs_dentry)
+static int cpuset_populate(struct cgroup_subsys *ss, struct cgroup *cont)
 {
 	int err;
 
-	if ((err = cpuset_add_file(cs_dentry, &cft_cpus)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_cpus)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_mems)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_mems)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_cpu_exclusive)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_cpu_exclusive)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_mem_exclusive)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_mem_exclusive)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_notify_on_release)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_memory_migrate)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_memory_migrate)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_memory_pressure)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_memory_pressure)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_spread_page)) < 0)
 		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_spread_page)) < 0)
-		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_spread_slab)) < 0)
-		return err;
-	if ((err = cpuset_add_file(cs_dentry, &cft_tasks)) < 0)
+	if ((err = cgroup_add_file(cont, ss, &cft_spread_slab)) < 0)
 		return err;
+	/* memory_pressure_enabled is in root cpuset only */
+	if (err == 0 && !cont->parent)
+		err = cgroup_add_file(cont, ss,
+					 &cft_memory_pressure_enabled);
 	return 0;
 }
 
 /*
+ * post_clone() is called at the end of cgroup_clone().
+ * 'cgroup' was just created automatically as a result of
+ * a cgroup_clone(), and the current task is about to
+ * be moved into 'cgroup'.
+ *
+ * Currently we refuse to set up the cgroup - thereby
+ * refusing the task to be entered, and as a result refusing
+ * the sys_unshare() or clone() which initiated it - if any
+ * sibling cpusets have exclusive cpus or mem.
+ *
+ * If this becomes a problem for some users who wish to
+ * allow that scenario, then cpuset_post_clone() could be
+ * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
+ * (and likewise for mems) to the new cgroup.
+ */
+static void cpuset_post_clone(struct cgroup_subsys *ss,
+			      struct cgroup *cgroup)
+{
+	struct cgroup *parent, *child;
+	struct cpuset *cs, *parent_cs;
+
+	parent = cgroup->parent;
+	list_for_each_entry(child, &parent->children, sibling) {
+		cs = cgroup_cs(child);
+		if (is_mem_exclusive(cs) || is_cpu_exclusive(cs))
+			return;
+	}
+	cs = cgroup_cs(cgroup);
+	parent_cs = cgroup_cs(parent);
+
+	cs->mems_allowed = parent_cs->mems_allowed;
+	cs->cpus_allowed = parent_cs->cpus_allowed;
+	return;
+}
+
+/*
  *	cpuset_create - create a cpuset
  *	parent:	cpuset that will be parent of the new cpuset.
  *	name:		name of the new cpuset. Will be strcpy'ed.
@@ -1841,106 +1244,60 @@ static int cpuset_populate_dir(struct dentry *cs_dentry)
  *	Must be called with the mutex on the parent inode held
  */
 
-static long cpuset_create(struct cpuset *parent, const char *name, int mode)
+static struct cgroup_subsys_state *cpuset_create(
+	struct cgroup_subsys *ss,
+	struct cgroup *cont)
 {
 	struct cpuset *cs;
-	int err;
+	struct cpuset *parent;
 
+	if (!cont->parent) {
+		/* This is early initialization for the top cgroup */
+		top_cpuset.mems_generation = cpuset_mems_generation++;
+		return &top_cpuset.css;
+	}
+	parent = cgroup_cs(cont->parent);
 	cs = kmalloc(sizeof(*cs), GFP_KERNEL);
 	if (!cs)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	mutex_lock(&manage_mutex);
 	cpuset_update_task_memory_state();
 	cs->flags = 0;
-	if (notify_on_release(parent))
-		set_bit(CS_NOTIFY_ON_RELEASE, &cs->flags);
 	if (is_spread_page(parent))
 		set_bit(CS_SPREAD_PAGE, &cs->flags);
 	if (is_spread_slab(parent))
 		set_bit(CS_SPREAD_SLAB, &cs->flags);
 	cs->cpus_allowed = CPU_MASK_NONE;
 	cs->mems_allowed = NODE_MASK_NONE;
-	atomic_set(&cs->count, 0);
-	INIT_LIST_HEAD(&cs->sibling);
-	INIT_LIST_HEAD(&cs->children);
 	cs->mems_generation = cpuset_mems_generation++;
 	fmeter_init(&cs->fmeter);
 
 	cs->parent = parent;
-
-	mutex_lock(&callback_mutex);
-	list_add(&cs->sibling, &cs->parent->children);
 	number_of_cpusets++;
-	mutex_unlock(&callback_mutex);
-
-	err = cpuset_create_dir(cs, name, mode);
-	if (err < 0)
-		goto err;
-
-	/*
-	 * Release manage_mutex before cpuset_populate_dir() because it
-	 * will down() this new directory's i_mutex and if we race with
-	 * another mkdir, we might deadlock.
-	 */
-	mutex_unlock(&manage_mutex);
-
-	err = cpuset_populate_dir(cs->dentry);
-	/* If err < 0, we have a half-filled directory - oh well ;) */
-	return 0;
-err:
-	list_del(&cs->sibling);
-	mutex_unlock(&manage_mutex);
-	kfree(cs);
-	return err;
-}
-
-static int cpuset_mkdir(struct inode *dir, struct dentry *dentry, int mode)
-{
-	struct cpuset *c_parent = dentry->d_parent->d_fsdata;
-
-	/* the vfs holds inode->i_mutex already */
-	return cpuset_create(c_parent, dentry->d_name.name, mode | S_IFDIR);
+	return &cs->css ;
 }
 
-static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
+static void cpuset_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
 {
-	struct cpuset *cs = dentry->d_fsdata;
-	struct dentry *d;
-	struct cpuset *parent;
-	char *pathbuf = NULL;
-
-	/* the vfs holds both inode->i_mutex already */
+	struct cpuset *cs = cgroup_cs(cont);
 
-	mutex_lock(&manage_mutex);
 	cpuset_update_task_memory_state();
-	if (atomic_read(&cs->count) > 0) {
-		mutex_unlock(&manage_mutex);
-		return -EBUSY;
-	}
-	if (!list_empty(&cs->children)) {
-		mutex_unlock(&manage_mutex);
-		return -EBUSY;
-	}
-	parent = cs->parent;
-	mutex_lock(&callback_mutex);
-	set_bit(CS_REMOVED, &cs->flags);
-	list_del(&cs->sibling);	/* delete my sibling from parent->children */
-	spin_lock(&cs->dentry->d_lock);
-	d = dget(cs->dentry);
-	cs->dentry = NULL;
-	spin_unlock(&d->d_lock);
-	cpuset_d_remove_dir(d);
-	dput(d);
 	number_of_cpusets--;
-	mutex_unlock(&callback_mutex);
-	if (list_empty(&parent->children))
-		check_for_release(parent, &pathbuf);
-	mutex_unlock(&manage_mutex);
-	cpuset_release_agent(pathbuf);
-	return 0;
+	kfree(cs);
 }
 
+struct cgroup_subsys cpuset_subsys = {
+	.name = "cpuset",
+	.create = cpuset_create,
+	.destroy  = cpuset_destroy,
+	.can_attach = cpuset_can_attach,
+	.attach = cpuset_attach,
+	.populate = cpuset_populate,
+	.post_clone = cpuset_post_clone,
+	.subsys_id = cpuset_subsys_id,
+	.early_init = 1,
+};
+
 /*
  * cpuset_init_early - just enough so that the calls to
  * cpuset_update_task_memory_state() in early init code
@@ -1949,13 +1306,11 @@ static int cpuset_rmdir(struct inode *unused_dir, struct dentry *dentry)
 
 int __init cpuset_init_early(void)
 {
-	struct task_struct *tsk = current;
-
-	tsk->cpuset = &top_cpuset;
-	tsk->cpuset->mems_generation = cpuset_mems_generation++;
+	top_cpuset.mems_generation = cpuset_mems_generation++;
 	return 0;
 }
 
+
 /**
  * cpuset_init - initialize cpusets at system boot
  *
@@ -1964,8 +1319,7 @@ int __init cpuset_init_early(void)
 
 int __init cpuset_init(void)
 {
-	struct dentry *root;
-	int err;
+	int err = 0;
 
 	top_cpuset.cpus_allowed = CPU_MASK_ALL;
 	top_cpuset.mems_allowed = NODE_MASK_ALL;
@@ -1973,30 +1327,12 @@ int __init cpuset_init(void)
 	fmeter_init(&top_cpuset.fmeter);
 	top_cpuset.mems_generation = cpuset_mems_generation++;
 
-	init_task.cpuset = &top_cpuset;
-
 	err = register_filesystem(&cpuset_fs_type);
 	if (err < 0)
-		goto out;
-	cpuset_mount = kern_mount(&cpuset_fs_type);
-	if (IS_ERR(cpuset_mount)) {
-		printk(KERN_ERR "cpuset: could not mount!\n");
-		err = PTR_ERR(cpuset_mount);
-		cpuset_mount = NULL;
-		goto out;
-	}
-	root = cpuset_mount->mnt_sb->s_root;
-	root->d_fsdata = &top_cpuset;
-	inc_nlink(root->d_inode);
-	top_cpuset.dentry = root;
-	root->d_inode->i_op = &cpuset_dir_inode_operations;
+		return err;
+
 	number_of_cpusets = 1;
-	err = cpuset_populate_dir(root);
-	/* memory_pressure_enabled is in root cpuset only */
-	if (err == 0)
-		err = cpuset_add_file(root, &cft_memory_pressure_enabled);
-out:
-	return err;
+	return 0;
 }
 
 /*
@@ -2022,10 +1358,12 @@ out:
 
 static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
 {
+	struct cgroup *cont;
 	struct cpuset *c;
 
 	/* Each of our child cpusets mems must be online */
-	list_for_each_entry(c, &cur->children, sibling) {
+	list_for_each_entry(cont, &cur->css.cgroup->children, sibling) {
+		c = cgroup_cs(cont);
 		guarantee_online_cpus_mems_in_subtree(c);
 		if (!cpus_empty(c->cpus_allowed))
 			guarantee_online_cpus(c, &c->cpus_allowed);
@@ -2053,7 +1391,7 @@ static void guarantee_online_cpus_mems_in_subtree(const struct cpuset *cur)
 
 static void common_cpu_mem_hotplug_unplug(void)
 {
-	mutex_lock(&manage_mutex);
+	cgroup_lock();
 	mutex_lock(&callback_mutex);
 
 	guarantee_online_cpus_mems_in_subtree(&top_cpuset);
@@ -2061,7 +1399,7 @@ static void common_cpu_mem_hotplug_unplug(void)
 	top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
 
 	mutex_unlock(&callback_mutex);
-	mutex_unlock(&manage_mutex);
+	cgroup_unlock();
 }
 
 /*
@@ -2113,109 +1451,7 @@ void __init cpuset_init_smp(void)
 }
 
 /**
- * cpuset_fork - attach newly forked task to its parents cpuset.
- * @tsk: pointer to task_struct of forking parent process.
- *
- * Description: A task inherits its parent's cpuset at fork().
- *
- * A pointer to the shared cpuset was automatically copied in fork.c
- * by dup_task_struct().  However, we ignore that copy, since it was
- * not made under the protection of task_lock(), so might no longer be
- * a valid cpuset pointer.  attach_task() might have already changed
- * current->cpuset, allowing the previously referenced cpuset to
- * be removed and freed.  Instead, we task_lock(current) and copy
- * its present value of current->cpuset for our freshly forked child.
- *
- * At the point that cpuset_fork() is called, 'current' is the parent
- * task, and the passed argument 'child' points to the child task.
- **/
-
-void cpuset_fork(struct task_struct *child)
-{
-	task_lock(current);
-	child->cpuset = current->cpuset;
-	atomic_inc(&child->cpuset->count);
-	task_unlock(current);
-}
-
-/**
- * cpuset_exit - detach cpuset from exiting task
- * @tsk: pointer to task_struct of exiting process
- *
- * Description: Detach cpuset from @tsk and release it.
- *
- * Note that cpusets marked notify_on_release force every task in
- * them to take the global manage_mutex mutex when exiting.
- * This could impact scaling on very large systems.  Be reluctant to
- * use notify_on_release cpusets where very high task exit scaling
- * is required on large systems.
- *
- * Don't even think about derefencing 'cs' after the cpuset use count
- * goes to zero, except inside a critical section guarded by manage_mutex
- * or callback_mutex.   Otherwise a zero cpuset use count is a license to
- * any other task to nuke the cpuset immediately, via cpuset_rmdir().
- *
- * This routine has to take manage_mutex, not callback_mutex, because
- * it is holding that mutex while calling check_for_release(),
- * which calls kmalloc(), so can't be called holding callback_mutex().
- *
- * the_top_cpuset_hack:
- *
- *    Set the exiting tasks cpuset to the root cpuset (top_cpuset).
- *
- *    Don't leave a task unable to allocate memory, as that is an
- *    accident waiting to happen should someone add a callout in
- *    do_exit() after the cpuset_exit() call that might allocate.
- *    If a task tries to allocate memory with an invalid cpuset,
- *    it will oops in cpuset_update_task_memory_state().
- *
- *    We call cpuset_exit() while the task is still competent to
- *    handle notify_on_release(), then leave the task attached to
- *    the root cpuset (top_cpuset) for the remainder of its exit.
- *
- *    To do this properly, we would increment the reference count on
- *    top_cpuset, and near the very end of the kernel/exit.c do_exit()
- *    code we would add a second cpuset function call, to drop that
- *    reference.  This would just create an unnecessary hot spot on
- *    the top_cpuset reference count, to no avail.
- *
- *    Normally, holding a reference to a cpuset without bumping its
- *    count is unsafe.   The cpuset could go away, or someone could
- *    attach us to a different cpuset, decrementing the count on
- *    the first cpuset that we never incremented.  But in this case,
- *    top_cpuset isn't going away, and either task has PF_EXITING set,
- *    which wards off any attach_task() attempts, or task is a failed
- *    fork, never visible to attach_task.
- *
- *    Another way to do this would be to set the cpuset pointer
- *    to NULL here, and check in cpuset_update_task_memory_state()
- *    for a NULL pointer.  This hack avoids that NULL check, for no
- *    cost (other than this way too long comment ;).
- **/
-
-void cpuset_exit(struct task_struct *tsk)
-{
-	struct cpuset *cs;
-
-	task_lock(current);
-	cs = tsk->cpuset;
-	tsk->cpuset = &top_cpuset;	/* the_top_cpuset_hack - see above */
-	task_unlock(current);
-
-	if (notify_on_release(cs)) {
-		char *pathbuf = NULL;
 
-		mutex_lock(&manage_mutex);
-		if (atomic_dec_and_test(&cs->count))
-			check_for_release(cs, &pathbuf);
-		mutex_unlock(&manage_mutex);
-		cpuset_release_agent(pathbuf);
-	} else {
-		atomic_dec(&cs->count);
-	}
-}
-
-/**
  * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
  * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
  *
@@ -2231,7 +1467,7 @@ cpumask_t cpuset_cpus_allowed(struct task_struct *tsk)
 
 	mutex_lock(&callback_mutex);
 	task_lock(tsk);
-	guarantee_online_cpus(tsk->cpuset, &mask);
+	guarantee_online_cpus(task_cs(tsk), &mask);
 	task_unlock(tsk);
 	mutex_unlock(&callback_mutex);
 
@@ -2259,7 +1495,7 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
 
 	mutex_lock(&callback_mutex);
 	task_lock(tsk);
-	guarantee_online_mems(tsk->cpuset, &mask);
+	guarantee_online_mems(task_cs(tsk), &mask);
 	task_unlock(tsk);
 	mutex_unlock(&callback_mutex);
 
@@ -2390,7 +1626,7 @@ int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
 	mutex_lock(&callback_mutex);
 
 	task_lock(current);
-	cs = nearest_exclusive_ancestor(current->cpuset);
+	cs = nearest_exclusive_ancestor(task_cs(current));
 	task_unlock(current);
 
 	allowed = node_isset(node, cs->mems_allowed);
@@ -2550,14 +1786,12 @@ int cpuset_memory_pressure_enabled __read_mostly;
 
 void __cpuset_memory_pressure_bump(void)
 {
-	struct cpuset *cs;
-
 	task_lock(current);
-	cs = current->cpuset;
-	fmeter_markevent(&cs->fmeter);
+	fmeter_markevent(&task_cs(current)->fmeter);
 	task_unlock(current);
 }
 
+#ifdef CONFIG_PROC_PID_CPUSET
 /*
  * proc_cpuset_show()
  *  - Print tasks cpuset path into seq_file.
@@ -2574,6 +1808,7 @@ static int proc_cpuset_show(struct seq_file *m, void *v)
 	struct pid *pid;
 	struct task_struct *tsk;
 	char *buf;
+	struct cgroup_subsys_state *css;
 	int retval;
 
 	retval = -ENOMEM;
@@ -2588,15 +1823,15 @@ static int proc_cpuset_show(struct seq_file *m, void *v)
 		goto out_free;
 
 	retval = -EINVAL;
-	mutex_lock(&manage_mutex);
-
-	retval = cpuset_path(tsk->cpuset, buf, PAGE_SIZE);
+	cgroup_lock();
+	css = task_subsys_state(tsk, cpuset_subsys_id);
+	retval = cgroup_path(css->cgroup, buf, PAGE_SIZE);
 	if (retval < 0)
 		goto out_unlock;
 	seq_puts(m, buf);
 	seq_putc(m, '\n');
 out_unlock:
-	mutex_unlock(&manage_mutex);
+	cgroup_unlock();
 	put_task_struct(tsk);
 out_free:
 	kfree(buf);
@@ -2616,6 +1851,7 @@ const struct file_operations proc_cpuset_operations = {
 	.llseek		= seq_lseek,
 	.release	= single_release,
 };
+#endif /* CONFIG_PROC_PID_CPUSET */
 
 /* Display task cpus_allowed, mems_allowed in /proc/<pid>/status file. */
 char *cpuset_task_status_allowed(struct task_struct *task, char *buffer)
diff --git a/kernel/exit.c b/kernel/exit.c
index 44ff6147556..cf03a52c3a9 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -31,7 +31,6 @@
 #include <linux/taskstats_kern.h>
 #include <linux/delayacct.h>
 #include <linux/freezer.h>
-#include <linux/cpuset.h>
 #include <linux/cgroup.h>
 #include <linux/syscalls.h>
 #include <linux/signal.h>
@@ -973,7 +972,6 @@ fastcall NORET_TYPE void do_exit(long code)
 	__exit_fs(tsk);
 	check_stack_usage();
 	exit_thread();
-	cpuset_exit(tsk);
 	cgroup_exit(tsk, 1);
 	exit_keys(tsk);
 
diff --git a/kernel/fork.c b/kernel/fork.c
index fcac3892924..61516b89cb6 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -29,7 +29,6 @@
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
 #include <linux/cpu.h>
-#include <linux/cpuset.h>
 #include <linux/cgroup.h>
 #include <linux/security.h>
 #include <linux/swap.h>
@@ -1089,7 +1088,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 #endif
 	p->io_context = NULL;
 	p->audit_context = NULL;
-	cpuset_fork(p);
 	cgroup_fork(p);
 #ifdef CONFIG_NUMA
  	p->mempolicy = mpol_copy(p->mempolicy);
@@ -1330,7 +1328,6 @@ bad_fork_cleanup_policy:
 	mpol_free(p->mempolicy);
 bad_fork_cleanup_cgroup:
 #endif
-	cpuset_exit(p);
 	cgroup_exit(p, cgroup_callbacks_done);
 bad_fork_cleanup_delays_binfmt:
 	delayacct_tsk_free(p);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 568152ae6ca..7fef5ebfaf1 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1388,7 +1388,6 @@ EXPORT_SYMBOL(alloc_pages_current);
  * keeps mempolicies cpuset relative after its cpuset moves.  See
  * further kernel/cpuset.c update_nodemask().
  */
-void *cpuset_being_rebound;
 
 /* Slow path of a mempolicy copy */
 struct mempolicy *__mpol_copy(struct mempolicy *old)
@@ -2019,4 +2018,3 @@ out:
 		m->version = (vma != priv->tail_vma) ? vma->vm_start : 0;
 	return 0;
 }
-