When we free a page whose order is very close to MAX_ORDER and greater than pageblock_order, it wastes some CPU cycles to increase max_order to MAX_ORDER one by one and check the pageblock migratetype of that page repeatedly especially when MAX_ORDER is much larger than pageblock_order.
Signed-off-by: Muchun Song <[email protected]> --- mm/page_alloc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 141f12e5142c..959541234e1d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1041,7 +1041,7 @@ static inline void __free_one_page(struct page *page, pfn = combined_pfn; order++; } - if (max_order < MAX_ORDER) { + if (max_order < MAX_ORDER && order < MAX_ORDER - 1) { /* 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 @@ -1062,6 +1062,8 @@ static inline void __free_one_page(struct page *page, is_migrate_isolate(buddy_mt))) goto done_merging; } + if (unlikely(order != max_order - 1)) + max_order = order + 1; max_order++; goto continue_merging; } -- 2.11.0
