- Support merging free block which was created by reallocing to smaller

- size. This should fix some performance issues. This code is still not
- thoroughly tested.

diff --git a/Zend/zend_mm.c b/Zend/zend_mm.c
index 7740b224ca86f58ada54f12cc19be87fbc3e3642..7e3511542b4f94d38453979f9509f31ff4e79d14 100644 (file)
--- a/Zend/zend_mm.c
+++ b/Zend/zend_mm.c
@@ -377,15 +377,25 @@ void *zend_mm_realloc(zend_mm_heap *heap, void *p, size_t size)
        zend_mm_block *next_block;
        size_t true_size = MAX(ZEND_MM_ALIGNED_SIZE(size)+ZEND_MM_ALIGNED_HEADER_SIZE, ZEND_MM_ALIGNED_FREE_HEADER_SIZE);
 
+       next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
+
        if (true_size <= mm_block->size) {
                zend_mm_create_new_free_block(heap, mm_block, true_size);
-               /* We don't yet merge this free block with the following one */
 
+               if (next_block->type == ZEND_MM_FREE_BLOCK) {
+                       zend_mm_block *new_next_block;
+
+                       new_next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
+                       if (new_next_block != next_block) { /* A new free block was created */
+                               zend_mm_remove_from_free_list(heap, (zend_mm_free_block *) next_block);
+                               new_next_block->size += next_block->size;
+                               /* update the next block's prev_size */
+                               ZEND_MM_BLOCK_AT(mm_block, new_next_block->size)->prev_size = new_next_block->size;
+                       }
+               }
                return p;
        }
 
-       next_block = ZEND_MM_BLOCK_AT(mm_block, mm_block->size);
-
        if ((mm_block->prev_size == 0) && (next_block->type == ZEND_MM_USED_BLOCK) &&
                (next_block->guard_block)) {
                zend_mm_segment *segment = (zend_mm_segment *) ((char *)mm_block - ZEND_MM_ALIGNED_SEGMENT_SIZE);