Merge branch 'PHP-7.1'

* PHP-7.1:
  Fixded bug #72736 (Slow performance when fetching large dataset with mysqli / PDO)

1 files changed, 11 insertions, 0 deletions

diff --git a/Zend/zend_alloc.c b/Zend/zend_alloc.c
index f52ce7985e..a3003a457a 100644
--- a/Zend/zend_alloc.c
+++ b/Zend/zend_alloc.c
@@ -851,6 +851,7 @@ static void *zend_mm_alloc_pages(zend_mm_heap *heap, uint32_t pages_count ZEND_F
 {
 	zend_mm_chunk *chunk = heap->main_chunk;
 	uint32_t page_num, len;
+	int steps = 0;
 
 	while (1) {
 		if (UNEXPECTED(chunk->free_pages < pages_count)) {
@@ -1027,10 +1028,20 @@ get_chunk:
 			goto found;
 		} else {
 			chunk = chunk->next;
+			steps++;
 		}
 	}
 
 found:
+	if (steps > 2 && pages_count < 8) {
+		/* move chunk into the head of the linked-list */
+		chunk->prev->next = chunk->next;
+		chunk->next->prev = chunk->prev;
+		chunk->next = heap->main_chunk->next;
+		chunk->prev = heap->main_chunk;
+		chunk->prev->next = chunk;
+		chunk->next->prev = chunk;
+	}
 	/* mark run as allocated */
 	chunk->free_pages -= pages_count;
 	zend_mm_bitset_set_range(chunk->free_map, page_num, pages_count);