From: chenqiwu <chenqiwu@xxxxxxxxxx>
Simplify page_is_buddy() to reduce the redundant code for better code
readability.
Signed-off-by: chenqiwu <chenqiwu@xxxxxxxxxx>
---
changes in v3:
- exchange the first two condition statements in v2 because the page type
must be checked first.
---
mm/page_alloc.c | 32 +++++++++++++-------------------
1 file changed, 13 insertions(+), 19 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3c4eb75..412f5d5 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -794,29 +794,23 @@ static inline void set_page_order(struct page *page, unsigned int order)
static inline int page_is_buddy(struct page *page, struct page *buddy,
unsigned int order)
{
- if (page_is_guard(buddy) && page_order(buddy) == order) {
- if (page_zone_id(page) != page_zone_id(buddy))
- return 0;
-
- VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
+ if (!page_is_guard(buddy) && !PageBuddy(buddy))
+ return 0;
- return 1;
- }
+ if (page_order(buddy) != order)
+ return 0;
- if (PageBuddy(buddy) && page_order(buddy) == order) {
- /*
- * zone check is done late to avoid uselessly
- * calculating zone/node ids for pages that could
- * never merge.
- */
- if (page_zone_id(page) != page_zone_id(buddy))
- return 0;
+ /*
+ * zone check is done late to avoid uselessly
+ * calculating zone/node ids for pages that could
+ * never merge.
+ */
+ if (page_zone_id(page) != page_zone_id(buddy))
+ return 0;
- VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
+ VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
- return 1;
- }
- return 0;
+ return 1;
}
#ifdef CONFIG_COMPACTION
--
1.9.1
