Buddy allocator: track size of buddy_returns

src/buddy.c

@@ -2010,8 +2010,10 @@ BUDDYF(return)(struct buddy_returns *rets)
 	map = buddy->map;
 	CHECK_OBJ_NOTNULL(map, BUDDY_MAP_MAGIC);
 
-	if (rets->n == 0)
+	if (rets->n == 0) {
+		AZ(rets->size);
 		return;
+	}
 
 	for (u = 0, a = rets->i_return; u < rets->n; u++, a++) {
 		CHECK_OBJ(a, I_RETURN_MAGIC);
@@ -2036,6 +2038,7 @@ BUDDYF(return)(struct buddy_returns *rets)
 
 	memset(rets->i_return, 0, rets->n * sizeof *rets->i_return);
 	rets->n = 0;
+	rets->size = 0;
 }
 
 /*

src/buddy.h

@@ -333,6 +333,7 @@ struct buddy_returns {
 	uint8_t		n;	// how many requests
 
 	buddy_t		*buddy;
+	size_t			size;
 	struct i_return		*i_return;
 };
 
@@ -722,6 +723,8 @@ BUDDYF(return_off_page)(struct buddy_returns *rets, struct buddy_off_page *page)
 	a->size = (size_t)1 << page->bits;
 	a->page = ipageof(buddy, page->off, page->bits);
 
+	rets->size += a->size;
+
 	*page = buddy_off_page_nil;
 
 	if (rets->n == rets->space)
@@ -775,6 +778,8 @@ BUDDYF(return_off_extent)(struct buddy_returns *rets,
 	a->size = extent->size;
 	a->page = ipageof(buddy, extent->off, a->bits);
 
+	rets->size += a->size;
+
 	*extent = buddy_off_extent_nil;
 
 	if (rets->n == rets->space)