Index: sys/vm/uma_int.h
===================================================================
--- sys/vm/uma_int.h	(revision 249764)
+++ sys/vm/uma_int.h	(working copy)
@@ -332,6 +332,7 @@
 	uint64_t	uz_sleeps;	/* Total number of alloc sleeps */
 	uint16_t	uz_fills;	/* Outstanding bucket fills */
 	uint16_t	uz_count;	/* Highest amount of items in bucket */
+	uint16_t	uz_countcap;	/* Cap on the # of items in bucket */
 
 	/* The next three fields are used to print a rate-limited warnings. */
 	const char	*uz_warning;	/* Warning to print on failure */
Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c	(revision 249764)
+++ sys/vm/uma_core.c	(working copy)
@@ -189,6 +189,9 @@
 #define	BUCKET_MAX	128
 
 struct uma_bucket_zone bucket_zones[] = {
+	{ NULL, "2 Buckets", 2},
+	{ NULL, "4 Buckets", 4},
+	{ NULL, "8 Buckets", 8},
 	{ NULL, "16 Bucket", 16 },
 	{ NULL, "32 Bucket", 32 },
 	{ NULL, "64 Bucket", 64 },
@@ -196,7 +199,7 @@
 	{ NULL, NULL, 0}
 };
 
-#define	BUCKET_SHIFT	4
+#define	BUCKET_SHIFT	1
 #define	BUCKET_ZONES	((BUCKET_MAX >> BUCKET_SHIFT) + 1)
 
 /*
@@ -1463,6 +1466,7 @@
 	uma_zone_t zone = mem;
 	uma_zone_t z;
 	uma_keg_t keg;
+	int i, exp;
 
 	bzero(zone, size);
 	zone->uz_name = arg->name;
@@ -1537,12 +1541,25 @@
 		return (0);
 	}
 
-	if (keg->uk_flags & UMA_ZONE_MAXBUCKET)
-		zone->uz_count = BUCKET_MAX;
-	else if (keg->uk_ipers <= BUCKET_MAX)
-		zone->uz_count = keg->uk_ipers;
+	/*
+	 * Put a cap on the maximum number of items a per-CPU cache
+	 * can hold. This way I can avoid KVA exaustion.
+	 */
+	if (zone->uz_size <= PAGE_SIZE) {
+		exp = zone->uz_size >> 6;
+		zone->uz_countcap = (exp >= 1) ? exp : 1;
+	} else {
+		exp = fls(1 << 17) - fls(zone->uz_size);
+		zone->uz_countcap = (exp > 0) ? 1 << ((uint16_t)exp + 1) : 1;
+	}
+	zone->uz_countcap--;
+	for (i = 1; i <= 16; i *= 2)
+		zone->uz_countcap |= zone->uz_countcap >> i;
+	zone->uz_countcap++;
+	if (keg->uk_ipers & UMA_ZONE_MAXBUCKET)
+		zone->uz_count = zone->uz_countcap;
 	else
-		zone->uz_count = BUCKET_MAX;
+		zone->uz_count = 1;
 	return (0);
 }
 
@@ -2178,7 +2195,7 @@
 	critical_exit();
 
 	/* Bump up our uz_count so we get here less */
-	if (zone->uz_count < BUCKET_MAX)
+	if (zone->uz_count < zone->uz_countcap)
 		zone->uz_count++;
 
 	/*