bitmap: Don't allocate excessive memory.

ROUND_UP rounds up to a multiple of a given value.  That means that
bitmap_allocate() was allocating one byte for each bit in the bitmap,
which is clearly excessive.

Instead, just allocate one bit for every bit in the bitmap.

diff --git a/lib/bitmap.h b/lib/bitmap.h
index 9c420eb64d23719ea8260ed7b6a737ff6108bec9..204281030e2b8e7a04a275084d047692789188fc 100644 (file)
--- a/lib/bitmap.h
+++ b/lib/bitmap.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008 Nicira Networks.
+ * Copyright (c) 2008, 2009 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -38,7 +38,8 @@ bitmap_bit__(size_t offset)
 static inline unsigned long *
 bitmap_allocate(size_t n_bits)
 {
-    return xcalloc(1, ROUND_UP(n_bits, BITMAP_ULONG_BITS));
+    size_t n_longs = DIV_ROUND_UP(n_bits, BITMAP_ULONG_BITS);
+    return xcalloc(sizeof(unsigned long int), n_longs);
 }
 
 static inline void

diff --git a/lib/util.h b/lib/util.h
index a945eb2757baafef582ddb259b71c42b73554cbb..dad7b7c4047523f9cb71653e29260ee16272a533 100644 (file)
--- a/lib/util.h
+++ b/lib/util.h
@@ -53,7 +53,8 @@
 extern const char *program_name;
 
 #define ARRAY_SIZE(ARRAY) (sizeof ARRAY / sizeof *ARRAY)
-#define ROUND_UP(X, Y) (((X) + ((Y) - 1)) / (Y) * (Y))
+#define DIV_ROUND_UP(X, Y) (((X) + ((Y) - 1)) / (Y))
+#define ROUND_UP(X, Y) (DIV_ROUND_UP(X, Y) * (Y))
 #define ROUND_DOWN(X, Y) ((X) / (Y) * (Y))
 #define IS_POW2(X) ((X) && !((X) & ((X) - 1)))