Index: sys/kern/subr_blist.c
===================================================================
--- sys/kern/subr_blist.c
+++ sys/kern/subr_blist.c
@@ -121,7 +121,7 @@
 #define free(a,b)	free(a)
 #define ummin(a,b)	((a) < (b) ? (a) : (b))
 
-#include <sys/blist.h>
+#include "../sys/blist.h"
 
 void panic(const char *ctl, ...);
 
@@ -1042,23 +1042,76 @@
 main(int ac, char **av)
 {
 	int size = BLIST_META_RADIX * BLIST_BMAP_RADIX;
+	int histAlloc, histSize, evCount, nEvents;
 	int i;
 	blist_t bl;
 	struct sbuf *s;
 
+	histAlloc = 0;
+	nEvents = 0;
 	for (i = 1; i < ac; ++i) {
 		const char *ptr = av[i];
 		if (*ptr != '-') {
 			size = strtol(ptr, NULL, 0);
 			continue;
 		}
-		ptr += 2;
-		fprintf(stderr, "Bad option: %s\n", ptr - 2);
-		exit(1);
+		switch (*++ptr) {
+		case 'r':
+		  srandom(strtol(av[++i], NULL, 0));
+		  break;
+		case 'h':
+		  histAlloc = strtol(av[++i], NULL, 0);
+		  break;
+		case 'n':
+		  nEvents = strtol(av[++i], NULL, 0);
+		  break;
+		default:
+		  fprintf(stderr, "Bad option: %s. \n"
+			  "Usage: -r <random seed> "
+			  "-h <history size> -n <num events>\n",
+			  ptr);
+		  exit(1);
+		}
 	}
 	bl = blist_create(size, M_WAITOK);
 	blist_free(bl, 0, size);
 
+	/*
+	 * Initialize with nEvents random allocation and free events.
+	 * Maintain a history of active allocations so that one can
+	 * be selected randomly for freeing.  On average, there are
+	 * histAlloc/2 outstanding allocations after startup, if
+	 * memory is big enough.
+	 */
+	struct {
+		daddr_t addr;
+		long long size;
+	} *history;
+	history = malloc(histAlloc * sizeof(history[0]), 0, 0);
+	histSize = 0;
+	for (evCount = 0; evCount < nEvents; ++evCount) {
+		long r = random();
+		int ev = r % histAlloc;
+		if (ev >= histSize) {
+			r /= histAlloc;
+			long long hsize = 1 + r % BLIST_MAX_ALLOC;
+			history[histSize].size = hsize;
+			history[histSize].addr = blist_alloc(bl, hsize);
+			if (history[histSize].addr != SWAPBLK_NONE)
+				++histSize;
+			else {
+			  blist_fill(bl, 0, size);
+			  blist_free(bl, 0, size);
+			  histSize = 0;
+			}
+		}
+		else {
+			blist_free(bl, history[ev].addr, history[ev].size);
+			history[ev] = history[--histSize];
+		}
+	}
+	free(history, 0);
+		
 	for (;;) {
 		char buf[1024];
 		long long da = 0;