diff --git a/sys/vm/vm_zone.c b/sys/vm/vm_zone.c
index 503e536..fe4faf9 100644
--- a/sys/vm/vm_zone.c
+++ b/sys/vm/vm_zone.c
@@ -31,7 +31,9 @@
 #include <vm/vm_kern.h>
 #include <vm/vm_extern.h>
 #include <vm/vm_zone.h>
-#include <sys/spinlock2.h>		/* XXX */
+
+#include <sys/spinlock2.h>
+#include <sys/mplock2.h>
 
 static MALLOC_DEFINE(M_ZONE, "ZONE", "Zone header");
 
@@ -39,8 +41,6 @@ static MALLOC_DEFINE(M_ZONE, "ZONE", "Zone header");
 #define	ZONE_ERROR_NOTFREE 1
 #define	ZONE_ERROR_ALREADYFREE 2
 
-#define	ZONE_ROUNDING	32
-
 #define	ZENTRY_FREE	0x12342378
 
 static void *zget(vm_zone_t z);
@@ -159,7 +159,7 @@ zinitna(vm_zone_t z, vm_object_t obj, char *name, int size,
 		panic("zinitna: can't create destroyable zone");
 
 	if ((z->zflags & ZONE_BOOT) == 0) {
-		z->zsize = (size + ZONE_ROUNDING - 1) & ~(ZONE_ROUNDING - 1);
+		z->zsize = size;
 		spin_init(&z->zlock);
 		z->zfreecnt = 0;
 		z->ztotal = 0;
@@ -372,6 +372,7 @@ zget(vm_zone_t z)
 		 * Interrupt zones do not mess with the kernel_map, they
 		 * simply populate an existing mapping.
 		 */
+		get_mplock();
 		nbytes = z->zpagecount * PAGE_SIZE;
 		nbytes -= nbytes % z->zsize;
 		item = (char *) z->zkva + nbytes;
@@ -401,6 +402,7 @@ zget(vm_zone_t z)
 			vmstats.v_wire_count++;
 		}
 		nitems = ((z->zpagecount * PAGE_SIZE) - nbytes) / z->zsize;
+		rel_mplock();
 	} else if (z->zflags & ZONE_SPECIAL) {
 		/*
 		 * The special zone is the one used for vm_map_entry_t's.