diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 24e69ebdbb3b958a7ca2408487d60a60f875c2fd..cdf444111f8c49c09068d1ff5d576c82a1e42d9c 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -41,8 +41,8 @@
  * MaxFSMRequestSize, exclusive.
  *
  * MaxFSMRequestSize depends on the architecture and BLCKSZ, but assuming
- * default 8k BLCKSZ, and that MaxFSMRequestSize is 24 bytes, the categories
- * look like this
+ * default 8k BLCKSZ, and that MaxFSMRequestSize is 8164 bytes, the
+ * categories look like this:
  *
  *
  * Range	 Category