branches/zip: Introduce the constant BUF_BUDDY_HIGH.

include/buf0buddy.ic

@@ -39,7 +39,7 @@ buf_buddy_get_offset(
 {
 	ut_ad(ut_is_2pow(size));
 	ut_ad(size >= BUF_BUDDY_LOW);
-	ut_ad(size < BUF_BUDDY_LOW << BUF_BUDDY_SIZES);
+	ut_ad(size < BUF_BUDDY_HIGH);
 
 	if (((ulint) page) & size) {
 		return(-(lint) size);

include/buf0buf.h

@@ -1171,8 +1171,8 @@ struct buf_pool_struct{
 					/* unmodified compressed pages */
 	UT_LIST_BASE_NODE_T(buf_page_t) zip_free[BUF_BUDDY_SIZES];
 					/* buddy free lists */
-#if BUF_BUDDY_LOW << BUF_BUDDY_SIZES != UNIV_PAGE_SIZE
-# error "BUF_BUDDY_LOW << BUF_BUDDY_SIZES != UNIV_PAGE_SIZE"
+#if BUF_BUDDY_HIGH != UNIV_PAGE_SIZE
+# error "BUF_BUDDY_HIGH != UNIV_PAGE_SIZE"
 #endif
 #if BUF_BUDDY_LOW > PAGE_ZIP_MIN_SIZE
 # error "BUF_BUDDY_LOW > PAGE_ZIP_MIN_SIZE"

include/buf0types.h

@@ -43,5 +43,10 @@ enum buf_io_fix {
 # define BUF_BUDDY_SIZES	7
 #endif
 
+/* twice the maximum block size of the buddy system;
+the underlying memory is aligned by this amount:
+this must be equal to UNIV_PAGE_SIZE */
+#define BUF_BUDDY_HIGH	(BUF_BUDDY_LOW << BUF_BUDDY_SIZES)
+
 #endif