diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
index c19c6e21e968..d685f7e39ab7 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c
@@ -5269,7 +5269,7 @@ arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag, boolean_t do_ada
 		 * If we are growing the cache, and we are adding anonymous
 		 * data, and we have outgrown arc_p, update arc_p
 		 */
-		if (aggsum_compare(&arc_size, arc_c) < 0 &&
+		if (aggsum_upper_bound(&arc_size) < arc_c &&
 		    hdr->b_l1hdr.b_state == arc_anon &&
 		    (refcount_count(&arc_anon->arcs_size) +
 		    refcount_count(&arc_mru->arcs_size) > arc_p))