diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index f23f7c58dc1c..82a95500c5d7 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_exit.c,v 1.198 2008/01/02 11:48:49 ad Exp $	*/
+/*	$NetBSD: kern_exit.c,v 1.199 2008/01/28 12:22:46 yamt Exp $	*/
 
 /*-
  * Copyright (c) 1998, 1999, 2006, 2007 The NetBSD Foundation, Inc.
@@ -74,7 +74,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.198 2008/01/02 11:48:49 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.199 2008/01/28 12:22:46 yamt Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_perfctrs.h"
@@ -308,9 +308,6 @@ exit1(struct lwp *l, int rv)
 	if (p->p_emul->e_proc_exit)
 		(*p->p_emul->e_proc_exit)(p);
 
-	/* Collect child u-areas. */
-	uvm_uarea_drain(false);
-
 	/*
 	 * Free the VM resources we're still holding on to.
 	 * We must do this from a valid thread because doing
@@ -1001,11 +998,6 @@ proc_free(struct proc *p, struct rusage *ru)
 	rw_destroy(&p->p_reflock);
 
 	proc_free_mem(p);
-
-	/*
-	 * Collect child u-areas.
-	 */
-	uvm_uarea_drain(false);
 }
 
 /*
diff --git a/sys/sys/cpu_data.h b/sys/sys/cpu_data.h
index eb7228867d45..42ddca77e534 100644
--- a/sys/sys/cpu_data.h
+++ b/sys/sys/cpu_data.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: cpu_data.h,v 1.15 2008/01/14 12:40:02 yamt Exp $	*/
+/*	$NetBSD: cpu_data.h,v 1.16 2008/01/28 12:22:46 yamt Exp $	*/
 
 /*-
  * Copyright (c) 2004, 2006, 2007 The NetBSD Foundation, Inc.
@@ -88,9 +88,6 @@ struct cpu_data {
 	void		*cpu_softcpu;		/* soft interrupt table */
 	TAILQ_HEAD(,buf) cpu_biodone;		/* finished block xfers */
 	u_int		cpu_softints;		/* pending (slow) softints */
-	kmutex_t	cpu_uarea_lock;		/* uarea alloc lock */
-	u_int		cpu_uarea_cnt;		/* count of free uareas */
-	vaddr_t		cpu_uarea_list;		/* free uareas */
 	percpu_cpu_t	cpu_percpu;		/* per-cpu data */
 };
 
diff --git a/sys/uvm/uvm_extern.h b/sys/uvm/uvm_extern.h
index ac6804b76f98..5566c36ecb68 100644
--- a/sys/uvm/uvm_extern.h
+++ b/sys/uvm/uvm_extern.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_extern.h,v 1.143 2008/01/02 11:49:16 ad Exp $	*/
+/*	$NetBSD: uvm_extern.h,v 1.144 2008/01/28 12:22:47 yamt Exp $	*/
 
 /*
  *
@@ -590,7 +590,6 @@ void			uvm_kick_scheduler(void);
 void			uvm_swapin(struct lwp *);
 bool			uvm_uarea_alloc(vaddr_t *);
 void			uvm_uarea_free(vaddr_t, struct cpu_info *);
-void			uvm_uarea_drain(bool);
 int			uvm_vslock(struct vmspace *, void *, size_t, vm_prot_t);
 void			uvm_vsunlock(struct vmspace *, void *, size_t);
 void			uvm_lwp_hold(struct lwp *);
diff --git a/sys/uvm/uvm_glue.c b/sys/uvm/uvm_glue.c
index f21219085cfc..986eecd2c75d 100644
--- a/sys/uvm/uvm_glue.c
+++ b/sys/uvm/uvm_glue.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_glue.c,v 1.114 2008/01/02 11:49:16 ad Exp $	*/
+/*	$NetBSD: uvm_glue.c,v 1.115 2008/01/28 12:22:47 yamt Exp $	*/
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.114 2008/01/02 11:49:16 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.115 2008/01/28 12:22:47 yamt Exp $");
 
 #include "opt_coredump.h"
 #include "opt_kgdb.h"
@@ -285,9 +285,71 @@ void
 uvm_cpu_attach(struct cpu_info *ci)
 {
 
-	mutex_init(&ci->ci_data.cpu_uarea_lock, MUTEX_DEFAULT, IPL_NONE);
-	ci->ci_data.cpu_uarea_cnt = 0;
-	ci->ci_data.cpu_uarea_list = 0;
+}
+
+static int
+uarea_swapin(vaddr_t addr)
+{
+
+	return uvm_fault_wire(kernel_map, addr, addr + USPACE,
+	    VM_PROT_READ | VM_PROT_WRITE, 0);
+}
+
+static void
+uarea_swapout(vaddr_t addr)
+{
+
+	uvm_fault_unwire(kernel_map, addr, addr + USPACE);
+}
+
+#ifndef USPACE_ALIGN
+#define	USPACE_ALIGN	0
+#endif
+
+static pool_cache_t uvm_uarea_cache;
+
+static int
+uarea_ctor(void *arg, void *obj, int flags)
+{
+
+	KASSERT((flags & PR_WAITOK) != 0);
+	return uarea_swapin((vaddr_t)obj);
+}
+
+static void *
+uarea_poolpage_alloc(struct pool *pp, int flags)
+{
+
+	return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz,
+	    USPACE_ALIGN, UVM_KMF_PAGEABLE |
+	    ((flags & PR_WAITOK) != 0 ? UVM_KMF_WAITVA :
+	    (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK)));
+}
+
+static void
+uarea_poolpage_free(struct pool *pp, void *addr)
+{
+
+	uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz,
+	    UVM_KMF_PAGEABLE);
+}
+
+static struct pool_allocator uvm_uarea_allocator = {
+	.pa_alloc = uarea_poolpage_alloc,
+	.pa_free = uarea_poolpage_free,
+	.pa_pagesz = USPACE,
+};
+
+void
+uvm_uarea_init(void)
+{
+
+	uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0,
+#if USPACE_ALIGN == 0
+	    PR_NOALIGN |
+#endif
+	    PR_NOTOUCH,
+	    "uarea", &uvm_uarea_allocator, IPL_NONE, uarea_ctor, NULL, NULL);
 }
 
 /*
@@ -297,32 +359,9 @@ uvm_cpu_attach(struct cpu_info *ci)
 bool
 uvm_uarea_alloc(vaddr_t *uaddrp)
 {
-	struct cpu_info *ci;
-	vaddr_t uaddr;
 
-#ifndef USPACE_ALIGN
-#define USPACE_ALIGN    0
-#endif
-
-	ci = curcpu();
-
-	if (ci->ci_data.cpu_uarea_cnt > 0) {
-		mutex_enter(&ci->ci_data.cpu_uarea_lock);
-		if (ci->ci_data.cpu_uarea_cnt == 0) {
-			mutex_exit(&ci->ci_data.cpu_uarea_lock);
-		} else {
-			uaddr = ci->ci_data.cpu_uarea_list;
-			ci->ci_data.cpu_uarea_list = UAREA_NEXTFREE(uaddr);
-			ci->ci_data.cpu_uarea_cnt--;
-			mutex_exit(&ci->ci_data.cpu_uarea_lock);
-			*uaddrp = uaddr;
-			return true;
-		}
-	}
-
-	*uaddrp = uvm_km_alloc(kernel_map, USPACE, USPACE_ALIGN,
-	    UVM_KMF_PAGEABLE);
-	return false;
+	*uaddrp = (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK);
+	return true;
 }
 
 /*
@@ -333,63 +372,7 @@ void
 uvm_uarea_free(vaddr_t uaddr, struct cpu_info *ci)
 {
 
-	mutex_enter(&ci->ci_data.cpu_uarea_lock);
-	UAREA_NEXTFREE(uaddr) = ci->ci_data.cpu_uarea_list;
-	ci->ci_data.cpu_uarea_list = uaddr;
-	ci->ci_data.cpu_uarea_cnt++;
-	mutex_exit(&ci->ci_data.cpu_uarea_lock);
-}
-
-/*
- * uvm_uarea_drain: return memory of u-areas over limit
- * back to system
- *
- * => if asked to drain as much as possible, drain all cpus.
- * => if asked to drain to low water mark, drain local cpu only.
- */
-
-void
-uvm_uarea_drain(bool empty)
-{
-	CPU_INFO_ITERATOR cii;
-	struct cpu_info *ci;
-	vaddr_t uaddr, nuaddr;
-	int count;
-
-	if (empty) {
-		for (CPU_INFO_FOREACH(cii, ci)) {
-			mutex_enter(&ci->ci_data.cpu_uarea_lock);
-			count = ci->ci_data.cpu_uarea_cnt;
-			uaddr = ci->ci_data.cpu_uarea_list;
-			ci->ci_data.cpu_uarea_cnt = 0;
-			ci->ci_data.cpu_uarea_list = 0;
-			mutex_exit(&ci->ci_data.cpu_uarea_lock);
-
-			while (count != 0) {
-				nuaddr = UAREA_NEXTFREE(uaddr);
-				uvm_km_free(kernel_map, uaddr, USPACE,
-				    UVM_KMF_PAGEABLE);
-				uaddr = nuaddr;
-				count--;
-			}
-		}
-		return;
-	}
-
-	ci = curcpu();
-	if (ci->ci_data.cpu_uarea_cnt > UVM_NUAREA_HIWAT) {
-		mutex_enter(&ci->ci_data.cpu_uarea_lock);
-		while (ci->ci_data.cpu_uarea_cnt > UVM_NUAREA_LOWAT) {
-			uaddr = ci->ci_data.cpu_uarea_list;
-			ci->ci_data.cpu_uarea_list = UAREA_NEXTFREE(uaddr);
-			ci->ci_data.cpu_uarea_cnt--;
-			mutex_exit(&ci->ci_data.cpu_uarea_lock);
-			uvm_km_free(kernel_map, uaddr, USPACE,
-			    UVM_KMF_PAGEABLE);
-			mutex_enter(&ci->ci_data.cpu_uarea_lock);
-		}
-		mutex_exit(&ci->ci_data.cpu_uarea_lock);
-	}
+	pool_cache_put(uvm_uarea_cache, (void *)uaddr);
 }
 
 /*
@@ -472,16 +455,12 @@ int	swapdebug = 0;
 void
 uvm_swapin(struct lwp *l)
 {
-	vaddr_t addr;
 	int error;
 
 	/* XXXSMP notyet KASSERT(mutex_owned(&l->l_swaplock)); */
 	KASSERT(l != curlwp);
 
-	addr = USER_TO_UAREA(l->l_addr);
-	/* make L_INMEM true */
-	error = uvm_fault_wire(kernel_map, addr, addr + USPACE,
-	    VM_PROT_READ | VM_PROT_WRITE, 0);
+	error = uarea_swapin(USER_TO_UAREA(l->l_addr));
 	if (error) {
 		panic("uvm_swapin: rewiring stack failed: %d", error);
 	}
@@ -758,7 +737,6 @@ uvm_swapout_threads(void)
 static void
 uvm_swapout(struct lwp *l)
 {
-	vaddr_t addr;
 	struct proc *p = l->l_proc;
 
 	KASSERT(mutex_owned(&l->l_swaplock));
@@ -796,8 +774,7 @@ uvm_swapout(struct lwp *l)
 	/*
 	 * Unwire the to-be-swapped process's user struct and kernel stack.
 	 */
-	addr = USER_TO_UAREA(l->l_addr);
-	uvm_fault_unwire(kernel_map, addr, addr + USPACE); /* !L_INMEM */
+	uarea_swapout(USER_TO_UAREA(l->l_addr));
 	pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map));
 }
 
diff --git a/sys/uvm/uvm_glue.h b/sys/uvm/uvm_glue.h
index 56500f022ae1..112d712263e4 100644
--- a/sys/uvm/uvm_glue.h
+++ b/sys/uvm/uvm_glue.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_glue.h,v 1.8 2005/12/11 12:25:29 christos Exp $	*/
+/*	$NetBSD: uvm_glue.h,v 1.9 2008/01/28 12:22:47 yamt Exp $	*/
 
 /*
  *
@@ -45,6 +45,8 @@
 
 void uvm_swapout_threads(void);
 
+void uvm_uarea_init(void);
+
 #endif /* _KERNEL */
 
 #endif /* _UVM_UVM_GLUE_H_ */
diff --git a/sys/uvm/uvm_init.c b/sys/uvm/uvm_init.c
index d0f0e9c257c5..86129b4f7aa1 100644
--- a/sys/uvm/uvm_init.c
+++ b/sys/uvm/uvm_init.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_init.c,v 1.31 2008/01/02 11:49:17 ad Exp $	*/
+/*	$NetBSD: uvm_init.c,v 1.32 2008/01/28 12:22:47 yamt Exp $	*/
 
 /*
  *
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_init.c,v 1.31 2008/01/02 11:49:17 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_init.c,v 1.32 2008/01/28 12:22:47 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -177,6 +177,8 @@ uvm_init(void)
 
 	uvm_anon_init();
 
+	uvm_uarea_init();
+
 	/*
 	 * init readahead module
 	 */
diff --git a/sys/uvm/uvm_pdaemon.c b/sys/uvm/uvm_pdaemon.c
index d0cacf7fede1..7cac2f934785 100644
--- a/sys/uvm/uvm_pdaemon.c
+++ b/sys/uvm/uvm_pdaemon.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_pdaemon.c,v 1.89 2008/01/02 11:49:19 ad Exp $	*/
+/*	$NetBSD: uvm_pdaemon.c,v 1.90 2008/01/28 12:22:47 yamt Exp $	*/
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -71,7 +71,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_pdaemon.c,v 1.89 2008/01/02 11:49:19 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_pdaemon.c,v 1.90 2008/01/28 12:22:47 yamt Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_readahead.h"
@@ -327,11 +327,6 @@ uvm_pageout(void *arg)
 		buf_drain(bufcnt << PAGE_SHIFT);
 		mutex_exit(&bufcache_lock);
 
-		/*
-		 * free any cached u-areas we don't need
-		 */
-		uvm_uarea_drain(true);
-
 		/*
 		 * complete draining the pools.
 		 */