1 files changed, 25 insertions, 5 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a6326c71b663..596180fedd3a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -475,6 +475,8 @@ static inline void __free_one_page(struct page *page,
                 int migratetype)
 {
         unsigned long page_idx;
+        unsigned long combined_idx;
+        struct page *buddy;
 
         if (unlikely(PageCompound(page)))
                 if (unlikely(destroy_compound_page(page, order)))
@@ -488,9 +490,6 @@ static inline void __free_one_page(struct page *page,
         VM_BUG_ON(bad_range(zone, page));
 
         while (order < MAX_ORDER-1) {
-                unsigned long combined_idx;
-                struct page *buddy;
-
                 buddy = __page_find_buddy(page, page_idx, order);
                 if (!page_is_buddy(page, buddy, order))
                         break;
@@ -505,8 +504,29 @@ static inline void __free_one_page(struct page *page,
                 order++;
         }
         set_page_order(page, order);
-        list_add(&page->lru,
-                &zone->free_area[order].free_list[migratetype]);
+
+        /*
+         * If this is not the largest possible page, check if the buddy
+         * of the next-highest order is free. If it is, it's possible
+         * that pages are being freed that will coalesce soon. In case,
+         * that is happening, add the free page to the tail of the list
+         * so it's less likely to be used soon and more likely to be merged
+         * as a higher order page
+         */
+        if ((order < MAX_ORDER-1) && pfn_valid_within(page_to_pfn(buddy))) {
+                struct page *higher_page, *higher_buddy;
+                combined_idx = __find_combined_index(page_idx, order);
+                higher_page = page + combined_idx - page_idx;
+                higher_buddy = __page_find_buddy(higher_page, combined_idx, order + 1);
+                if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
+                        list_add_tail(&page->lru,
+                                &zone->free_area[order].free_list[migratetype]);
+                        goto out;
+                }
+        }
+
+        list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
+out:
         zone->free_area[order].nr_free++;
 }