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-rw-r--r--mm/page_alloc.c41
1 files changed, 14 insertions, 27 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9f689f16b5aa..fd11b913779e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -467,29 +467,6 @@ static inline void rmv_page_order(struct page *page)
}
/*
- * Locate the struct page for both the matching buddy in our
- * pair (buddy1) and the combined O(n+1) page they form (page).
- *
- * 1) Any buddy B1 will have an order O twin B2 which satisfies
- * the following equation:
- * B2 = B1 ^ (1 << O)
- * For example, if the starting buddy (buddy2) is #8 its order
- * 1 buddy is #10:
- * B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
- *
- * 2) Any buddy B will have an order O+1 parent P which
- * satisfies the following equation:
- * P = B & ~(1 << O)
- *
- * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
- */
-static inline unsigned long
-__find_buddy_index(unsigned long page_idx, unsigned int order)
-{
- return page_idx ^ (1 << order);
-}
-
-/*
* This function checks whether a page is free && is the buddy
* we can do coalesce a page and its buddy if
* (a) the buddy is not in a hole &&
@@ -569,6 +546,7 @@ static inline void __free_one_page(struct page *page,
unsigned long combined_idx;
unsigned long uninitialized_var(buddy_idx);
struct page *buddy;
+ int max_order = MAX_ORDER;
VM_BUG_ON(!zone_is_initialized(zone));
@@ -577,15 +555,24 @@ static inline void __free_one_page(struct page *page,
return;
VM_BUG_ON(migratetype == -1);
- if (!is_migrate_isolate(migratetype))
+ if (is_migrate_isolate(migratetype)) {
+ /*
+ * We restrict max order of merging to prevent merge
+ * between freepages on isolate pageblock and normal
+ * pageblock. Without this, pageblock isolation
+ * could cause incorrect freepage accounting.
+ */
+ max_order = min(MAX_ORDER, pageblock_order + 1);
+ } else {
__mod_zone_freepage_state(zone, 1 << order, migratetype);
+ }
- page_idx = pfn & ((1 << MAX_ORDER) - 1);
+ page_idx = pfn & ((1 << max_order) - 1);
VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
VM_BUG_ON_PAGE(bad_range(zone, page), page);
- while (order < MAX_ORDER-1) {
+ while (order < max_order - 1) {
buddy_idx = __find_buddy_index(page_idx, order);
buddy = page + (buddy_idx - page_idx);
if (!page_is_buddy(page, buddy, order))
@@ -1486,7 +1473,7 @@ void split_page(struct page *page, unsigned int order)
}
EXPORT_SYMBOL_GPL(split_page);
-static int __isolate_free_page(struct page *page, unsigned int order)
+int __isolate_free_page(struct page *page, unsigned int order)
{
unsigned long watermark;
struct zone *zone;