diff options
Diffstat (limited to 'mm/page_isolation.c')
| -rw-r--r-- | mm/page_isolation.c | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 1fa4a4d72ecc..c8778f7e208e 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -76,17 +76,54 @@ void unset_migratetype_isolate(struct page *page, unsigned migratetype) { struct zone *zone; unsigned long flags, nr_pages; + struct page *isolated_page = NULL; + unsigned int order; + unsigned long page_idx, buddy_idx; + struct page *buddy; zone = page_zone(page); spin_lock_irqsave(&zone->lock, flags); if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) goto out; - nr_pages = move_freepages_block(zone, page, migratetype); - __mod_zone_freepage_state(zone, nr_pages, migratetype); + + /* + * Because freepage with more than pageblock_order on isolated + * pageblock is restricted to merge due to freepage counting problem, + * it is possible that there is free buddy page. + * move_freepages_block() doesn't care of merge so we need other + * approach in order to merge them. Isolation and free will make + * these pages to be merged. + */ + if (PageBuddy(page)) { + order = page_order(page); + if (order >= pageblock_order) { + page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1); + buddy_idx = __find_buddy_index(page_idx, order); + buddy = page + (buddy_idx - page_idx); + + if (!is_migrate_isolate_page(buddy)) { + __isolate_free_page(page, order); + set_page_refcounted(page); + isolated_page = page; + } + } + } + + /* + * If we isolate freepage with more than pageblock_order, there + * should be no freepage in the range, so we could avoid costly + * pageblock scanning for freepage moving. + */ + if (!isolated_page) { + nr_pages = move_freepages_block(zone, page, migratetype); + __mod_zone_freepage_state(zone, nr_pages, migratetype); + } set_pageblock_migratetype(page, migratetype); zone->nr_isolate_pageblock--; out: spin_unlock_irqrestore(&zone->lock, flags); + if (isolated_page) + __free_pages(isolated_page, order); } static inline struct page * |