diff options
| -rw-r--r-- | mm/page_alloc.c | 30 |
1 files changed, 25 insertions, 5 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a6326c7..596180f 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++; } |
