When the caller of buf_flush_list() provides us with the number of

pages that it wants to flush then we should honor that value as in
not going beyond that in our eagerness to flush the neighbors of
the selected victim.

storage/innobase/buf/buf0flu.c

@@ -1248,8 +1248,12 @@ buf_flush_try_neighbors(
 /*====================*/
 	ulint		space,		/*!< in: space id */
 	ulint		offset,		/*!< in: page offset */
-	enum buf_flush	flush_type)	/*!< in: BUF_FLUSH_LRU or
+	enum buf_flush	flush_type,	/*!< in: BUF_FLUSH_LRU or
 					BUF_FLUSH_LIST */
+	ulint		n_flushed,	/*!< in: number of pages
+					flushed so far in this batch */
+	ulint		n_to_flush)	/*!< in: maximum number of pages
+					we are allowed to flush */
 {
 	ulint		i;
 	ulint		low;
@@ -1290,6 +1294,21 @@ buf_flush_try_neighbors(
 
 		buf_page_t*	bpage;
 
+		if ((count + n_flushed) >= n_to_flush) {
+
+			/* We have already flushed enough pages and
+			should call it a day. There is, however, one
+			exception. If the page whose neighbors we
+			are flushing has not been flushed yet then
+			we'll try to flush the victim that we
+			selected originally. */
+			if (i <= offset) {
+				i = offset;
+			} else {
+				break;
+			}
+		}
+
 		buf_pool = buf_pool_get(space, i);
 
 		buf_pool_mutex_enter(buf_pool);
@@ -1357,6 +1376,8 @@ buf_flush_page_and_try_neighbors(
 					buf_page_in_file(bpage) */
 	enum buf_flush	flush_type,	/*!< in: BUF_FLUSH_LRU
 					or BUF_FLUSH_LIST */
+	ulint		n_to_flush,	/*!< in: number of pages to
+					flush */
 	ulint*		count)		/*!< in/out: number of pages
 					flushed */
 {
@@ -1390,7 +1411,11 @@ buf_flush_page_and_try_neighbors(
 		mutex_exit(block_mutex);
 
 		/* Try to flush also all the neighbors */
-		*count += buf_flush_try_neighbors(space, offset, flush_type);
+		*count += buf_flush_try_neighbors(space,
+						  offset,
+						  flush_type,
+						  *count,
+						  n_to_flush);
 
 		buf_pool_mutex_enter(buf_pool);
 		flushed = TRUE;
@@ -1430,7 +1455,7 @@ buf_flush_LRU_list_batch(
 		a page that isn't ready for flushing. */
 		while (bpage != NULL
 		       && !buf_flush_page_and_try_neighbors(
-				bpage, BUF_FLUSH_LRU, &count)) {
+				bpage, BUF_FLUSH_LRU, max, &count)) {
 
 			bpage = UT_LIST_GET_PREV(LRU, bpage);
 		}
@@ -1511,7 +1536,7 @@ buf_flush_flush_list_batch(
 		while (bpage != NULL
 		       && len > 0
 		       && !buf_flush_page_and_try_neighbors(
-				bpage, BUF_FLUSH_LIST, &count)) {
+				bpage, BUF_FLUSH_LIST, min_n, &count)) {
 
 			buf_flush_list_mutex_enter(buf_pool);