branches/zip: buf_buddy_alloc_clean(): Remove, as it violates the LRU policy.

buf/buf0buddy.c

@@ -269,134 +269,6 @@ buf_buddy_alloc_from(
 	return(buf);
 }
 
-/**************************************************************************
-Try to allocate a block by freeing an unmodified page. */
-static
-void*
-buf_buddy_alloc_clean(
-/*==================*/
-			/* out: allocated block, or NULL */
-	ulint	i,	/* in: index of buf_pool->zip_free[] */
-	ibool*	lru)	/* in: pointer to a variable that will be assigned
-			TRUE if storage was allocated from the LRU list
-			and buf_pool_mutex was temporarily released */
-{
-	buf_page_t*	bpage;
-
-	ut_ad(buf_pool_mutex_own());
-	ut_ad(!mutex_own(&buf_pool_zip_mutex));
-
-	if (buf_buddy_n_frames < buf_buddy_max_n_frames) {
-
-		goto free_LRU;
-	}
-
-	if (BUF_BUDDY_LOW << i >= PAGE_ZIP_MIN_SIZE
-	    && i < BUF_BUDDY_SIZES) {
-		/* Try to find a clean compressed-only page
-		of the same size. */
-
-		page_zip_des_t	dummy_zip;
-		ulint		j;
-
-		page_zip_set_size(&dummy_zip, BUF_BUDDY_LOW << i);
-
-		j = ut_min(UT_LIST_GET_LEN(buf_pool->zip_clean), 100);
-		bpage = UT_LIST_GET_FIRST(buf_pool->zip_clean);
-
-		mutex_enter(&buf_pool_zip_mutex);
-
-		for (; j--; bpage = UT_LIST_GET_NEXT(list, bpage)) {
-			if (bpage->zip.ssize != dummy_zip.ssize
-			    || !buf_LRU_free_block(bpage, FALSE, lru)) {
-
-				continue;
-			}
-
-			/* Reuse the block. */
-
-			mutex_exit(&buf_pool_zip_mutex);
-			bpage = buf_buddy_alloc_zip(i);
-
-			/* bpage may be NULL if buf_buddy_free()
-			[invoked by buf_LRU_free_block() via
-			buf_LRU_block_remove_hashed_page()]
-			recombines blocks and invokes
-			buf_buddy_block_free().  Because
-			buf_pool_mutex will not be released
-			after buf_buddy_block_free(), there will
-			be at least one block available in the
-			buffer pool, and thus it does not make sense
-			to deallocate any further compressed blocks. */
-
-			return(bpage);
-		}
-
-		mutex_exit(&buf_pool_zip_mutex);
-	}
-
-	/* Free blocks from the end of the LRU list until enough space
-	is available. */
-
-free_LRU:
-	for (bpage = UT_LIST_GET_LAST(buf_pool->LRU); bpage;
-	     bpage = UT_LIST_GET_PREV(LRU, bpage)) {
-
-		void*		ret;
-		mutex_t*	block_mutex = buf_page_get_mutex(bpage);
-
-		if (UNIV_UNLIKELY(!buf_page_in_file(bpage))) {
-
-			/* This is most likely BUF_BLOCK_REMOVE_HASH,
-			that is, the block is already being freed. */
-			continue;
-		}
-
-		mutex_enter(block_mutex);
-
-		/* Keep the compressed pages of uncompressed blocks. */
-		if (!buf_LRU_free_block(bpage, FALSE, lru)) {
-
-			mutex_exit(block_mutex);
-			continue;
-		}
-
-		mutex_exit(block_mutex);
-
-		/* The block was successfully freed.
-		Attempt to allocate memory. */
-
-		if (i < BUF_BUDDY_SIZES) {
-
-			ret = buf_buddy_alloc_zip(i);
-
-			if (ret) {
-
-				return(ret);
-			}
-		} else {
-			buf_block_t*	block = buf_LRU_get_free_only();
-
-			if (block) {
-				buf_buddy_block_register(block);
-				return(block->frame);
-			}
-		}
-
-		/* A successful buf_LRU_free_block() may release and
-		reacquire buf_pool_mutex, and thus bpage->LRU of
-		an uncompressed page may point to garbage.  Furthermore,
-		if bpage were a compressed page descriptor, it would
-		have been deallocated by buf_LRU_free_block().
-
-		Thus, we must restart the traversal of the LRU list. */
-
-		goto free_LRU;
-	}
-
-	return(NULL);
-}
-
 /**************************************************************************
 Allocate a block.  The thread calling this function must hold
 buf_pool_mutex and must not hold buf_pool_zip_mutex or any block->mutex.
@@ -442,15 +314,6 @@ buf_buddy_alloc_low(
 		return(NULL);
 	}
 
-	/* Try replacing a clean page in the buffer pool. */
-
-	block = buf_buddy_alloc_clean(i, lru);
-
-	if (block) {
-
-		goto func_exit;
-	}
-
 	/* Try replacing an uncompressed page in the buffer pool. */
 	buf_pool_mutex_exit();
 	block = buf_LRU_get_free_block(0);