branches/zip: When creating a memory heap, set the block size to what

was actually obtained from the buddy allocator.  This should avoid some
internal memory fragmentation in mem_heap_create() and mem_heap_alloc().

mem_area_alloc(): Change the in parameter size to an in/out parameter.
Adjust the size based on what was obtained from pool->free_list[].

mem_heap_create_block(): Adjust block->len to what was obtained from
mem_area_alloc().

include/mem0pool.h

@@ -50,9 +50,11 @@ void*
 mem_area_alloc(
 /*===========*/
 				/* out, own: allocated memory buffer */
-	ulint		size,	/* in: allocated size in bytes; for optimum
+	ulint*		psize,	/* in: requested size in bytes; for optimum
 				space usage, the size should be a power of 2
-				minus MEM_AREA_EXTRA_SIZE */
+				minus MEM_AREA_EXTRA_SIZE;
+				out: allocated size in bytes (greater than
+				or equal to the requested size) */
 	mem_pool_t*	pool);	/* in: memory pool */
 /************************************************************************
 Frees memory to a pool. */

mem/mem0mem.c

@@ -334,7 +334,7 @@ mem_heap_create_block(
 	if (type == MEM_HEAP_DYNAMIC) {
 
 		len = MEM_BLOCK_HEADER_SIZE + MEM_SPACE_NEEDED(n);
-		block = mem_area_alloc(len, mem_comm_pool);
+		block = mem_area_alloc(&len, mem_comm_pool);
 	} else {
 		ut_ad(n <= MEM_MAX_ALLOC_IN_BUF);
 
@@ -342,7 +342,7 @@ mem_heap_create_block(
 
 		if (len < UNIV_PAGE_SIZE / 2) {
 
-			block = mem_area_alloc(len, mem_comm_pool);
+			block = mem_area_alloc(&len, mem_comm_pool);
 		} else {
 			len = UNIV_PAGE_SIZE;
 

mem/mem0pool.c

@@ -324,15 +324,19 @@ void*
 mem_area_alloc(
 /*===========*/
 				/* out, own: allocated memory buffer */
-	ulint		size,	/* in: allocated size in bytes; for optimum
+	ulint*		psize,	/* in: requested size in bytes; for optimum
 				space usage, the size should be a power of 2
-				minus MEM_AREA_EXTRA_SIZE */
+				minus MEM_AREA_EXTRA_SIZE;
+				out: allocated size in bytes (greater than
+				or equal to the requested size) */
 	mem_pool_t*	pool)	/* in: memory pool */
 {
 	mem_area_t*	area;
+	ulint		size;
 	ulint		n;
 	ibool		ret;
 
+	size = *psize;
 	n = ut_2_log(ut_max(size + MEM_AREA_EXTRA_SIZE, MEM_AREA_MIN_SIZE));
 
 	mutex_enter(&(pool->mutex));
@@ -403,8 +407,9 @@ mem_area_alloc(
 	mutex_exit(&(pool->mutex));
 
 	ut_ad(mem_pool_validate(pool));
-	UNIV_MEM_ALLOC(MEM_AREA_EXTRA_SIZE + (byte*)area,
-		       ut_2_exp(n) - MEM_AREA_EXTRA_SIZE);
+
+	*psize = ut_2_exp(n) - MEM_AREA_EXTRA_SIZE;
+	UNIV_MEM_ALLOC(MEM_AREA_EXTRA_SIZE + (byte*)area, *psize);
 
 	return((void*)(MEM_AREA_EXTRA_SIZE + ((byte*)area)));
 }