[Devel] Playing with namespaces and bloat-o-meeter

Pavel Emelyanov xemul at openvz.org
Wed Sep 26 05:37:32 PDT 2007


Hi, guys!

I've noticed that compiling out all the core related to
cloning and cleaning the new namespace saves us more than
a Kbyte (!) from the vmlinux.

add/remove: 19/0 grow/shrink: 6/6 up/down: 1532/-336 (1196)
function                                     old     new   delta
copy_user_ns                                   -     181    +181
copy_ipcs                                      -     149    +149
copy_utsname                                   -     120    +120
shm_exit_ns                                    -     106    +106
sem_exit_ns                                    -     106    +106
msg_exit_ns                                    -     106    +106
freeary                                        -     100    +100
release_uids                                   -      95     +95
freeque                                        -      92     +92
free_nsproxy                                  48      99     +51
__sem_init_ns                                  -      45     +45
shm_init_ns                                    -      42     +42
sem_init_ns                                    -      42     +42
msg_init_ns                                    -      42     +42
__shm_init_ns                                  -      38     +38
create_new_namespaces                        300     335     +35
__msg_init_ns                                  -      31     +31
sysvipc_proc_release                           5      35     +30
free_ipc_ns                                    -      30     +30
do_shm_rmid                                    -      29     +29
shm_release                                   18      39     +21
free_user_ns                                   -      16     +16
sysvipc_proc_open                            100     111     +11
do_shmat                                     778     787      +9
free_uts_ns                                    -       5      +5
sys_shmctl                                  1934    1907     -27
msg_init                                      82      47     -35
shm_init                                      92      47     -45
sem_init                                      99      44     -55
sys_msgctl                                  1394    1311     -83
sys_semctl                                  2123    2032     -91

Since there already were some questions like "do I need it
on my cellphone?" in reply to pid namespaces patches and 
so on, why don't we make ALL the namespaces cloning code 
under the config option to make those people happy?

Here's the proposed patch.

Signed-off-by: Pavel Emelyanov <xemul at openvz.org>

---

diff --git a/include/linux/ipc.h b/include/linux/ipc.h
index 96988d1..b882610 100644
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -100,56 +100,6 @@ struct kern_ipc_perm
 	void		*security;
 };
 
-struct ipc_ids;
-struct ipc_namespace {
-	struct kref	kref;
-	struct ipc_ids	*ids[3];
-
-	int		sem_ctls[4];
-	int		used_sems;
-
-	int		msg_ctlmax;
-	int		msg_ctlmnb;
-	int		msg_ctlmni;
-
-	size_t		shm_ctlmax;
-	size_t		shm_ctlall;
-	int		shm_ctlmni;
-	int		shm_tot;
-};
-
-extern struct ipc_namespace init_ipc_ns;
-
-#ifdef CONFIG_SYSVIPC
-#define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
-extern void free_ipc_ns(struct kref *kref);
-extern struct ipc_namespace *copy_ipcs(unsigned long flags,
-						struct ipc_namespace *ns);
-#else
-#define INIT_IPC_NS(ns)
-static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
-						struct ipc_namespace *ns)
-{
-	return ns;
-}
-#endif
-
-static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
-{
-#ifdef CONFIG_SYSVIPC
-	if (ns)
-		kref_get(&ns->kref);
-#endif
-	return ns;
-}
-
-static inline void put_ipc_ns(struct ipc_namespace *ns)
-{
-#ifdef CONFIG_SYSVIPC
-	kref_put(&ns->kref, free_ipc_ns);
-#endif
-}
-
 #endif /* __KERNEL__ */
 
 #endif /* _LINUX_IPC_H */
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
new file mode 100644
index 0000000..89f51f8
--- /dev/null
+++ b/include/linux/ipc_namespace.h
@@ -0,0 +1,67 @@
+#ifndef __IPC_NAMESPACE_H__
+#define __IPC_NAMESPACE_H__
+
+#include <linux/err.h>
+
+struct ipc_ids;
+struct ipc_namespace {
+	struct kref	kref;
+	struct ipc_ids	*ids[3];
+
+	int		sem_ctls[4];
+	int		used_sems;
+
+	int		msg_ctlmax;
+	int		msg_ctlmnb;
+	int		msg_ctlmni;
+
+	size_t		shm_ctlmax;
+	size_t		shm_ctlall;
+	int		shm_ctlmni;
+	int		shm_tot;
+};
+
+extern struct ipc_namespace init_ipc_ns;
+
+#ifdef CONFIG_SYSVIPC
+#define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,
+#else
+#define INIT_IPC_NS(ns)
+#endif
+
+#ifdef CONFIG_NS_IPC
+extern void free_ipc_ns(struct kref *kref);
+extern struct ipc_namespace *copy_ipcs(unsigned long flags,
+						struct ipc_namespace *ns);
+
+static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
+{
+	if (ns)
+		kref_get(&ns->kref);
+	return ns;
+}
+
+static inline void put_ipc_ns(struct ipc_namespace *ns)
+{
+	kref_put(&ns->kref, free_ipc_ns);
+}
+#else
+static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
+		struct ipc_namespace *ns)
+{
+	if (flags & CLONE_NEWIPC)
+		return ERR_PTR(-EINVAL);
+
+	return ns;
+}
+
+static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
+{
+	return ns;
+}
+
+static inline void put_ipc_ns(struct ipc_namespace *ns)
+{
+}
+#endif
+#endif
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 4817c66..ac1b47f 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -122,7 +122,6 @@ extern struct pid *find_ge_pid(int nr, s
 
 extern struct pid *alloc_pid(struct pid_namespace *ns);
 extern void FASTCALL(free_pid(struct pid *pid));
-extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
 
 /*
  * the helpers to get the pid's id seen from different namespaces
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 0135c76..1f5f915 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -6,6 +6,7 @@
 #include <linux/threads.h>
 #include <linux/nsproxy.h>
 #include <linux/kref.h>
+#include <linux/err.h>
 
 struct pidmap {
        atomic_t nr_free;
@@ -29,6 +30,7 @@ struct pid_namespace {
 
 extern struct pid_namespace init_pid_ns;
 
+#ifdef CONFIG_NS_PID
 static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
 {
 	if (ns != &init_pid_ns)
@@ -38,12 +40,37 @@ static inline struct pid_namespace *get_
 
 extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);
 extern void free_pid_ns(struct kref *kref);
+extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
 
 static inline void put_pid_ns(struct pid_namespace *ns)
 {
 	if (ns != &init_pid_ns)
 		kref_put(&ns->kref, free_pid_ns);
 }
+#else
+static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
+{
+	return ns;
+}
+
+static inline void put_pid_ns(struct pid_namespace *ns)
+{
+}
+
+static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
+		struct pid_namespace *ns)
+{
+	if (flags & CLONE_NEWPID)
+		return ERR_PTR(-EINVAL);
+
+	return ns;
+}
+
+static inline void zap_pid_ns_processes(struct pid_namespace *ns)
+{
+	BUG();
+}
+#endif
 
 static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
 {
diff --git a/include/linux/sched.h b/include/linux/sched.h
diff --git a/include/linux/sem.h b/include/linux/sem.h
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index b5f41d4..d73080c 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -17,7 +17,7 @@ struct user_namespace {
 
 extern struct user_namespace init_user_ns;
 
-#ifdef CONFIG_USER_NS
+#ifdef CONFIG_NS_UID
 
 static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
 {
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 923db99..cea08a9 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -35,6 +35,7 @@ struct new_utsname {
 #include <linux/sched.h>
 #include <linux/kref.h>
 #include <linux/nsproxy.h>
+#include <linux/err.h>
 #include <asm/atomic.h>
 
 struct uts_namespace {
@@ -43,6 +44,7 @@ struct uts_namespace {
 };
 extern struct uts_namespace init_uts_ns;
 
+#ifdef CONFIG_NS_UTS
 static inline void get_uts_ns(struct uts_namespace *ns)
 {
 	kref_get(&ns->kref);
@@ -56,6 +58,25 @@ static inline void put_uts_ns(struct uts
 {
 	kref_put(&ns->kref, free_uts_ns);
 }
+#else
+static inline void get_uts_ns(struct uts_namespace *ns)
+{
+}
+
+static inline void put_uts_ns(struct uts_namespace *ns)
+{
+}
+
+static inline struct uts_namespace *copy_utsname(unsigned long flags,
+					struct uts_namespace *ns)
+{
+	if (flags & CLONE_NEWUTS)
+		return ERR_PTR(-EINVAL);
+
+	return ns;
+}
+#endif
+
 static inline struct new_utsname *utsname(void)
 {
 	return &current->nsproxy->uts_ns->name;
diff --git a/init/Kconfig b/init/Kconfig
index 684ccfb..ccb1575 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -206,15 +206,6 @@ config TASK_IO_ACCOUNTING
 
 	  Say N if unsure.
 
-config USER_NS
-	bool "User Namespaces (EXPERIMENTAL)"
-	default n
-	depends on EXPERIMENTAL
-	help
-	  Support user namespaces.  This allows containers, i.e.
-	  vservers, to use user namespaces to provide different
-	  user info for different servers.  If unsure, say N.
-
 config AUDIT
 	bool "Auditing support"
 	depends on NET
@@ -369,6 +360,39 @@ config RELAY
 
 	  If unsure, say N.
 
+config NAMESPACES
+	bool "The namespaces support"
+	help
+	  Provides the way to make tasks work with different objects using
+	  the same id
+
+config NS_UTS
+	bool "Uname namespace"
+	depends on NAMESPACES
+	help
+	  The utsname namespace
+
+config NS_IPC
+	bool "IPC namespace"
+	depends on NAMESPACES && SYSVIPC
+	help
+	  The SYSVIPC ids namespaces
+
+config NS_PIDS
+	bool "PID namespace"
+	depends on NAMESPACES
+	help
+	  Tasks see only the pids living in the same namespace and in the
+	  child namespaces
+
+config NS_UID
+	bool "UID namespace"
+	depends on NAMESPACES && EXPERIMENTAL
+	help
+	  Support user namespaces.  This allows containers, i.e.
+	  vservers, to use user namespaces to provide different
+	  user info for different servers.  If unsure, say N.
+
 config BLK_DEV_INITRD
 	bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
 	depends on BROKEN || !FRV
diff --git a/init/main.c b/init/main.c
diff --git a/ipc/Makefile b/ipc/Makefile
index b93bba6..b051636 100644
--- a/ipc/Makefile
+++ b/ipc/Makefile
@@ -7,4 +7,5 @@ obj-$(CONFIG_SYSVIPC) += util.o msgutil.
 obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o
 obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
+obj-$(CONFIG_NS_IPC) += namespace.o
 
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 79e24e8..7f4235b 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -14,6 +14,7 @@
 #include <linux/nsproxy.h>
 #include <linux/sysctl.h>
 #include <linux/uaccess.h>
+#include <linux/ipc_namespace.h>
 
 static void *get_ipc(ctl_table *table)
 {
diff --git a/ipc/msg.c b/ipc/msg.c
index b7274db..9406030 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -36,6 +36,7 @@
 #include <linux/seq_file.h>
 #include <linux/mutex.h>
 #include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
 
 #include <asm/current.h>
 #include <asm/uaccess.h>
@@ -92,6 +93,7 @@ static void __msg_init_ns(struct ipc_nam
 	ipc_init_ids(ids);
 }
 
+#ifdef CONFIG_NS_IPC
 int msg_init_ns(struct ipc_namespace *ns)
 {
 	struct ipc_ids *ids;
@@ -127,6 +129,7 @@ void msg_exit_ns(struct ipc_namespace *n
 	kfree(ns->ids[IPC_MSG_IDS]);
 	ns->ids[IPC_MSG_IDS] = NULL;
 }
+#endif
 
 void __init msg_init(void)
 {
diff --git a/ipc/namespace.c b/ipc/namespace.c
new file mode 100644
index 0000000..cef1139
--- /dev/null
+++ b/ipc/namespace.c
@@ -0,0 +1,73 @@
+/*
+ * linux/ipc/namespace.c
+ * Copyright (C) 2006 Pavel Emelyanov <xemul at openvz.org> OpenVZ, SWsoft Inc.
+ */
+
+#include <linux/ipc.h>
+#include <linux/msg.h>
+#include <linux/ipc_namespace.h>
+#include <linux/rcupdate.h>
+#include <linux/nsproxy.h>
+#include <linux/slab.h>
+
+#include "util.h"
+
+static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
+{
+	int err;
+	struct ipc_namespace *ns;
+
+	err = -ENOMEM;
+	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
+	if (ns == NULL)
+		goto err_mem;
+
+	err = sem_init_ns(ns);
+	if (err)
+		goto err_sem;
+	err = msg_init_ns(ns);
+	if (err)
+		goto err_msg;
+	err = shm_init_ns(ns);
+	if (err)
+		goto err_shm;
+
+	kref_init(&ns->kref);
+	return ns;
+
+err_shm:
+	msg_exit_ns(ns);
+err_msg:
+	sem_exit_ns(ns);
+err_sem:
+	kfree(ns);
+err_mem:
+	return ERR_PTR(err);
+}
+
+struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+{
+	struct ipc_namespace *new_ns;
+
+	BUG_ON(!ns);
+	get_ipc_ns(ns);
+
+	if (!(flags & CLONE_NEWIPC))
+		return ns;
+
+	new_ns = clone_ipc_ns(ns);
+
+	put_ipc_ns(ns);
+	return new_ns;
+}
+
+void free_ipc_ns(struct kref *kref)
+{
+	struct ipc_namespace *ns;
+
+	ns = container_of(kref, struct ipc_namespace, kref);
+	sem_exit_ns(ns);
+	msg_exit_ns(ns);
+	shm_exit_ns(ns);
+	kfree(ns);
+}
diff --git a/ipc/sem.c b/ipc/sem.c
index 45c7e57..a12d52e 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -82,6 +82,7 @@
 #include <linux/seq_file.h>
 #include <linux/mutex.h>
 #include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
 
 #include <asm/uaccess.h>
 #include "util.h"
@@ -130,6 +131,7 @@ static void __sem_init_ns(struct ipc_nam
 	ipc_init_ids(ids);
 }
 
+#ifdef CONFIG_NS_IPC
 int sem_init_ns(struct ipc_namespace *ns)
 {
 	struct ipc_ids *ids;
@@ -165,6 +167,7 @@ void sem_exit_ns(struct ipc_namespace *n
 	kfree(ns->ids[IPC_SEM_IDS]);
 	ns->ids[IPC_SEM_IDS] = NULL;
 }
+#endif
 
 void __init sem_init (void)
 {
diff --git a/ipc/shm.c b/ipc/shm.c
index f28f2a3..07db882 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -38,6 +38,7 @@
 #include <linux/mutex.h>
 #include <linux/nsproxy.h>
 #include <linux/mount.h>
+#include <linux/ipc_namespace.h>
 
 #include <asm/uaccess.h>
 
@@ -97,6 +98,7 @@ static void do_shm_rmid(struct ipc_names
 		shm_destroy(ns, shp);
 }
 
+#ifdef CONFIG_NS_IPC
 int shm_init_ns(struct ipc_namespace *ns)
 {
 	struct ipc_ids *ids;
@@ -132,6 +134,7 @@ void shm_exit_ns(struct ipc_namespace *n
 	kfree(ns->ids[IPC_SHM_IDS]);
 	ns->ids[IPC_SHM_IDS] = NULL;
 }
+#endif
 
 void __init shm_init (void)
 {
diff --git a/ipc/util.c b/ipc/util.c
index fd29246..44fb843 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -32,6 +32,7 @@
 #include <linux/proc_fs.h>
 #include <linux/audit.h>
 #include <linux/nsproxy.h>
+#include <linux/ipc_namespace.h>
 
 #include <asm/unistd.h>
 
@@ -50,66 +51,6 @@ struct ipc_namespace init_ipc_ns = {
 	},
 };
 
-static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
-{
-	int err;
-	struct ipc_namespace *ns;
-
-	err = -ENOMEM;
-	ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
-	if (ns == NULL)
-		goto err_mem;
-
-	err = sem_init_ns(ns);
-	if (err)
-		goto err_sem;
-	err = msg_init_ns(ns);
-	if (err)
-		goto err_msg;
-	err = shm_init_ns(ns);
-	if (err)
-		goto err_shm;
-
-	kref_init(&ns->kref);
-	return ns;
-
-err_shm:
-	msg_exit_ns(ns);
-err_msg:
-	sem_exit_ns(ns);
-err_sem:
-	kfree(ns);
-err_mem:
-	return ERR_PTR(err);
-}
-
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
-{
-	struct ipc_namespace *new_ns;
-
-	BUG_ON(!ns);
-	get_ipc_ns(ns);
-
-	if (!(flags & CLONE_NEWIPC))
-		return ns;
-
-	new_ns = clone_ipc_ns(ns);
-
-	put_ipc_ns(ns);
-	return new_ns;
-}
-
-void free_ipc_ns(struct kref *kref)
-{
-	struct ipc_namespace *ns;
-
-	ns = container_of(kref, struct ipc_namespace, kref);
-	sem_exit_ns(ns);
-	msg_exit_ns(ns);
-	shm_exit_ns(ns);
-	kfree(ns);
-}
-
 /**
  *	ipc_init	-	initialise IPC subsystem
  *
diff --git a/ipc/util.h b/ipc/util.h
index 99414a3..8972402 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -20,6 +20,8 @@ void sem_init (void);
 void msg_init (void);
 void shm_init (void);
 
+struct ipc_namespace;
+
 int sem_init_ns(struct ipc_namespace *ns);
 int msg_init_ns(struct ipc_namespace *ns);
 int shm_init_ns(struct ipc_namespace *ns);
diff --git a/kernel/Makefile b/kernel/Makefile
index 76f782f..299261c 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -4,12 +4,11 @@
 
 obj-y     = sched.o fork.o exec_domain.o panic.o printk.o profile.o \
 	    exit.o itimer.o time.o softirq.o resource.o \
-	    sysctl.o capability.o ptrace.o timer.o user.o user_namespace.o \
+	    sysctl.o capability.o ptrace.o timer.o user.o \
 	    signal.o sys.o kmod.o workqueue.o pid.o \
 	    rcupdate.o extable.o params.o posix-timers.o \
 	    kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
-	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o \
-	    utsname.o notifier.o sysctl.o
+	    hrtimer.o rwsem.o latency.o nsproxy.o srcu.o notifier.o sysctl.o
 
 obj-$(CONFIG_SYSCTL) += sysctl_check.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
@@ -50,6 +49,8 @@ obj-$(CONFIG_AUDITSYSCALL) += auditsc.o
 obj-$(CONFIG_AUDIT_TREE) += audit_tree.o
 obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_KGDB) += kgdb.o
+obj-$(CONFIG_NS_UTS) += utsname.o
+obj-$(CONFIG_NS_UID) += user_namespace.o
 obj-$(CONFIG_SYSFS) += ksysfs.o
 obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
 obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ee68964..5a27426 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -20,6 +20,7 @@
 #include <linux/mnt_namespace.h>
 #include <linux/utsname.h>
 #include <linux/pid_namespace.h>
+#include <linux/ipc_namespace.h>
 
 static struct kmem_cache *nsproxy_cachep;
 
diff --git a/kernel/pid.c b/kernel/pid.c
index e2e060e..a247fea 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -432,6 +432,7 @@ struct pid *find_ge_pid(int nr, struct p
 }
 EXPORT_SYMBOL_GPL(find_get_pid);
 
+#ifdef CONFIG_NS_PID
 struct pid_cache {
 	int nr_ids;
 	char name[16];
@@ -482,6 +483,11 @@ err_alloc:
 	return NULL;
 }
 
+static __init struct kmem_cache *create_init_pid_cachep(void)
+{
+	return create_pid_cachep(1);
+}
+
 static struct pid_namespace *create_pid_namespace(int level)
 {
 	struct pid_namespace *ns;
@@ -603,6 +609,13 @@ void zap_pid_ns_processes(struct pid_nam
 	pid_ns->child_reaper = NULL;
 	return;
 }
+#else
+static __init struct kmem_cache *create_init_pid_cachep(void)
+{
+	return kmem_cache_create("pid", sizeof(struct pid), 0,
+			SLAB_HWCACHE_ALIGN, NULL);
+}
+#endif
 
 /*
  * The pid hash table is scaled according to the amount of memory in the
@@ -636,7 +649,7 @@ void __init pidmap_init(void)
 	set_bit(0, init_pid_ns.pidmap[0].page);
 	atomic_dec(&init_pid_ns.pidmap[0].nr_free);
 
-	init_pid_ns.pid_cachep = create_pid_cachep(1);
+	init_pid_ns.pid_cachep = create_init_pid_cachep();
 	if (init_pid_ns.pid_cachep == NULL)
 		panic("Can't create pid_1 cachep\n");
 
diff --git a/kernel/user.c b/kernel/user.c
index b45f55f..d9cac1d 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -17,6 +17,15 @@
 #include <linux/module.h>
 #include <linux/user_namespace.h>
 
+struct user_namespace init_user_ns = {
+	.kref = {
+		.refcount	= ATOMIC_INIT(2),
+	},
+	.root_user = &root_user,
+};
+
+EXPORT_SYMBOL_GPL(init_user_ns);
+
 /*
  * UID task count cache, to get fast user lookup in "alloc_uid"
  * when changing user ID's (ie setuid() and friends).
@@ -199,6 +208,7 @@ void switch_uid(struct user_struct *new_
 	suid_keys(current);
 }
 
+#ifdef CONFIG_NS_UID
 void release_uids(struct user_namespace *ns)
 {
 	int i;
@@ -223,6 +233,7 @@ void release_uids(struct user_namespace 
 
 	free_uid(ns->root_user);
 }
+#endif
 
 static int __init uid_cache_init(void)
 {
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 7af90fc..4c90062 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -10,17 +10,6 @@
 #include <linux/nsproxy.h>
 #include <linux/user_namespace.h>
 
-struct user_namespace init_user_ns = {
-	.kref = {
-		.refcount	= ATOMIC_INIT(2),
-	},
-	.root_user = &root_user,
-};
-
-EXPORT_SYMBOL_GPL(init_user_ns);
-
-#ifdef CONFIG_USER_NS
-
 /*
  * Clone a new ns copying an original user ns, setting refcount to 1
  * @old_ns: namespace to clone
@@ -84,5 +73,3 @@ void free_user_ns(struct kref *kref)
 	release_uids(ns);
 	kfree(ns);
 }
-
-#endif /* CONFIG_USER_NS */
diff --git a/kernel/utsname.c b/kernel/utsname.c
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