Index: kern/subr_pool.c
===================================================================
RCS file: /cvsroot/src/sys/kern/subr_pool.c,v
retrieving revision 1.275
diff -p -u -r1.275 subr_pool.c
--- kern/subr_pool.c	19 Dec 2020 23:38:21 -0000	1.275
+++ kern/subr_pool.c	23 Feb 2021 05:30:54 -0000
@@ -3096,9 +3096,14 @@ pool_redzone_init(struct pool *pp, size_
 	/*
 	 * No space in the natural padding; check if we can extend a
 	 * bit the size of the pool.
+	 *
+	 * Avoid using redzone for allocations half of a page or larger.
+	 * For pagesize items, we'd waste a whole new page (could be
+	 * unmapped?), and for half pagesize items, approximately half
+	 * the space is lost (eg, 4K pages, you get one 2K allocation.)
 	 */
 	nsz = roundup(pp->pr_size + redzsz, pp->pr_align);
-	if (nsz <= pp->pr_alloc->pa_pagesz) {
+	if (nsz <= (pp->pr_alloc->pa_pagesz / 2)) {
 		/* Ok, we can */
 		pp->pr_size = nsz;
 		pp->pr_reqsize_with_redzone = requested_size + redzsz;