diff options
| -rw-r--r-- | mm/page_alloc.c | 95 |
1 files changed, 59 insertions, 36 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2ca3e9bd739c..b09ce5fe0cd2 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1008,6 +1008,52 @@ static void change_pageblock_range(struct page *pageblock_page, } } +/* + * If breaking a large block of pages, move all free pages to the preferred + * allocation list. If falling back for a reclaimable kernel allocation, be + * more aggressive about taking ownership of free pages. + * + * On the other hand, never change migration type of MIGRATE_CMA pageblocks + * nor move CMA pages to different free lists. We don't want unmovable pages + * to be allocated from MIGRATE_CMA areas. + * + * Returns the new migratetype of the pageblock (or the same old migratetype + * if it was unchanged). + */ +static int try_to_steal_freepages(struct zone *zone, struct page *page, + int start_type, int fallback_type) +{ + int current_order = page_order(page); + + if (is_migrate_cma(fallback_type)) + return fallback_type; + + /* Take ownership for orders >= pageblock_order */ + if (current_order >= pageblock_order) { + change_pageblock_range(page, current_order, start_type); + return start_type; + } + + if (current_order >= pageblock_order / 2 || + start_type == MIGRATE_RECLAIMABLE || + page_group_by_mobility_disabled) { + int pages; + + pages = move_freepages_block(zone, page, start_type); + + /* Claim the whole block if over half of it is free */ + if (pages >= (1 << (pageblock_order-1)) || + page_group_by_mobility_disabled) { + + set_pageblock_migratetype(page, start_type); + return start_type; + } + + } + + return fallback_type; +} + /* Remove an element from the buddy allocator from the fallback list */ static inline struct page * __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) @@ -1015,7 +1061,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) struct free_area *area; int current_order; struct page *page; - int migratetype, i; + int migratetype, new_type, i; /* Find the largest possible block of pages in the other list */ for (current_order = MAX_ORDER-1; current_order >= order; @@ -1035,51 +1081,28 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype) struct page, lru); area->nr_free--; - /* - * If breaking a large block of pages, move all free - * pages to the preferred allocation list. If falling - * back for a reclaimable kernel allocation, be more - * aggressive about taking ownership of free pages - * - * On the other hand, never change migration - * type of MIGRATE_CMA pageblocks nor move CMA - * pages on different free lists. We don't - * want unmovable pages to be allocated from - * MIGRATE_CMA areas. - */ - if (!is_migrate_cma(migratetype) && - (current_order >= pageblock_order / 2 || - start_migratetype == MIGRATE_RECLAIMABLE || - page_group_by_mobility_disabled)) { - int pages; - pages = move_freepages_block(zone, page, - start_migratetype); - - /* Claim the whole block if over half of it is free */ - if (pages >= (1 << (pageblock_order-1)) || - page_group_by_mobility_disabled) - set_pageblock_migratetype(page, - start_migratetype); - - migratetype = start_migratetype; - } + new_type = try_to_steal_freepages(zone, page, + start_migratetype, + migratetype); /* Remove the page from the freelists */ list_del(&page->lru); rmv_page_order(page); - /* Take ownership for orders >= pageblock_order */ - if (current_order >= pageblock_order && - !is_migrate_cma(migratetype)) - change_pageblock_range(page, current_order, - start_migratetype); - + /* + * Borrow the excess buddy pages as well, irrespective + * of whether we stole freepages, or took ownership of + * the pageblock or not. + * + * Exception: When borrowing from MIGRATE_CMA, release + * the excess buddy pages to CMA itself. + */ expand(zone, page, order, current_order, area, is_migrate_cma(migratetype) ? migratetype : start_migratetype); trace_mm_page_alloc_extfrag(page, order, current_order, - start_migratetype, migratetype); + start_migratetype, new_type); return page; } |