From 7f5a834fdb5f8c61eea21c66db2036c81fdfa302 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Mon, 19 Jan 2015 11:14:04 -0700
Subject: [PATCH] allow weak hash tables to shrink

---
 racket/src/racket/src/hash.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/racket/src/racket/src/hash.c b/racket/src/racket/src/hash.c
index 7436a7a3ff..2001aee756 100644
--- a/racket/src/racket/src/hash.c
+++ b/racket/src/racket/src/hash.c
@@ -795,6 +795,10 @@ get_bucket (Scheme_Bucket_Table *table, const char *key, int add, Scheme_Bucket
       if (actual * FILL_FACTOR < table->count) {
 	/* Decrement size so that the table won't actually grow. */
 	table->size >>= 1;
+        if ((table->size > 64) && (2 * actual * FILL_FACTOR < table->count)) {
+          /* Allow the table to shrink */
+          table->size >>= 1;
+        }
       }
     }