m_realloc: Account only allocation size difference in total_bytes_allocated.

pfalcon · pfalcon · commit 43f1c8080ae2 · 2014-01-03T18:55:23.000+02:00
diff --git a/py/malloc.c b/py/malloc.c
@@ -41,7 +41,12 @@ void *m_realloc(void *ptr, int old_num_bytes, int new_num_bytes) {
         printf("could not allocate memory, reallocating %d bytes\n", new_num_bytes);
         return NULL;
     }
-    total_bytes_allocated += new_num_bytes;
+    // At first thought, "Total bytes allocated" should only grow,
+    // after all, it's *total*. But consider for example 2K block
+    // shrunk to 1K and then grown to 2K again. It's still 2K
+    // allocated total. If we process only positive increments,
+    // we'll count 3K.
+    total_bytes_allocated += new_num_bytes - old_num_bytes;
     return ptr;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -41,7 +41,12 @@ void m_realloc(void ptr, int old_num_bytes, int new_num_bytes) {`
`41`	`41`	`printf("could not allocate memory, reallocating %d bytes\n", new_num_bytes);`
`42`	`42`	`return NULL;`
`43`	`43`	`}`
`44`		`- total_bytes_allocated += new_num_bytes;`
	`44`	`+ // At first thought, "Total bytes allocated" should only grow,`
	`45`	`+ // after all, it's total. But consider for example 2K block`
	`46`	`+ // shrunk to 1K and then grown to 2K again. It's still 2K`
	`47`	`+ // allocated total. If we process only positive increments,`
	`48`	`+ // we'll count 3K.`
	`49`	`+ total_bytes_allocated += new_num_bytes - old_num_bytes;`
`45`	`50`	`return ptr;`
`46`	`51`	`}`
`47`	`52`