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Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c46
1 files changed, 33 insertions, 13 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a762be57e46e..59de90d5d3a3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -692,34 +692,28 @@ static inline void __free_one_page(struct page *page,
unsigned long combined_idx;
unsigned long uninitialized_var(buddy_idx);
struct page *buddy;
- unsigned int max_order = MAX_ORDER;
+ unsigned int max_order;
+
+ max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1);
VM_BUG_ON(!zone_is_initialized(zone));
VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
VM_BUG_ON(migratetype == -1);
- 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_t(unsigned int, MAX_ORDER, pageblock_order + 1);
- } else {
+ if (likely(!is_migrate_isolate(migratetype)))
__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);
+continue_merging:
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))
- break;
+ goto done_merging;
/*
* Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
* merge with it and move up one order.
@@ -736,6 +730,32 @@ static inline void __free_one_page(struct page *page,
page_idx = combined_idx;
order++;
}
+ if (max_order < MAX_ORDER) {
+ /* If we are here, it means order is >= pageblock_order.
+ * We want to prevent merge between freepages on isolate
+ * pageblock and normal pageblock. Without this, pageblock
+ * isolation could cause incorrect freepage or CMA accounting.
+ *
+ * We don't want to hit this code for the more frequent
+ * low-order merging.
+ */
+ if (unlikely(has_isolate_pageblock(zone))) {
+ int buddy_mt;
+
+ buddy_idx = __find_buddy_index(page_idx, order);
+ buddy = page + (buddy_idx - page_idx);
+ buddy_mt = get_pageblock_migratetype(buddy);
+
+ if (migratetype != buddy_mt
+ && (is_migrate_isolate(migratetype) ||
+ is_migrate_isolate(buddy_mt)))
+ goto done_merging;
+ }
+ max_order++;
+ goto continue_merging;
+ }
+
+done_merging:
set_page_order(page, order);
/*