diff --git a/src/dict.c b/src/dict.c
index 0d4aacb7..77ce90cb 100644
--- a/src/dict.c
+++ b/src/dict.c
@@ -148,14 +148,12 @@ int dictExpand(dict *d, unsigned long size)
     if (dictIsRehashing(d) || d->ht[0].used > size)
         return DICT_ERR;
 
+    /* Allocate the new hashtable and initialize all pointers to NULL */
     n.size = realsize;
     n.sizemask = realsize-1;
-    n.table = zmalloc(realsize*sizeof(dictEntry*));
+    n.table = zcalloc(realsize*sizeof(dictEntry*));
     n.used = 0;
 
-    /* Initialize all the pointers to NULL */
-    memset(n.table, 0, realsize*sizeof(dictEntry*));
-
     /* Is this the first initialization? If so it's not really a rehashing
      * we just set the first hash table so that it can accept keys. */
     if (d->ht[0].table == NULL) {
diff --git a/src/vm.c b/src/vm.c
index 073cace2..0ccc5fe2 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -86,10 +86,9 @@ void vmInit(void) {
     } else {
         redisLog(REDIS_NOTICE,"Swap file allocated with success");
     }
-    server.vm_bitmap = zmalloc((server.vm_pages+7)/8);
+    server.vm_bitmap = zcalloc((server.vm_pages+7)/8);
     redisLog(REDIS_VERBOSE,"Allocated %lld bytes page table for %lld pages",
         (long long) (server.vm_pages+7)/8, server.vm_pages);
-    memset(server.vm_bitmap,0,(server.vm_pages+7)/8);
 
     /* Initialize threaded I/O (used by Virtual Memory) */
     server.io_newjobs = listCreate();
diff --git a/src/zmalloc.c b/src/zmalloc.c
index 8658376a..5c1b5e9a 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -89,6 +89,20 @@ void *zmalloc(size_t size) {
 #endif
 }
 
+void *zcalloc(size_t size) {
+    void *ptr = calloc(1, size+PREFIX_SIZE);
+
+    if (!ptr) zmalloc_oom(size);
+#ifdef HAVE_MALLOC_SIZE
+    increment_used_memory(redis_malloc_size(ptr));
+    return ptr;
+#else
+    *((size_t*)ptr) = size;
+    increment_used_memory(size+PREFIX_SIZE);
+    return (char*)ptr+PREFIX_SIZE;
+#endif
+}
+
 void *zrealloc(void *ptr, size_t size) {
 #ifndef HAVE_MALLOC_SIZE
     void *realptr;
diff --git a/src/zmalloc.h b/src/zmalloc.h
index 193e7eda..db858bba 100644
--- a/src/zmalloc.h
+++ b/src/zmalloc.h
@@ -32,6 +32,7 @@
 #define _ZMALLOC_H
 
 void *zmalloc(size_t size);
+void *zcalloc(size_t size);
 void *zrealloc(void *ptr, size_t size);
 void zfree(void *ptr);
 char *zstrdup(const char *s);