The freepage_migratetype is a temporary cached value which represents the free page's pageblock migratetype. Now we use it in two scenarios:
1. Use it as a cached value in page freeing path. This cached value is temporary and non-100% update, which help us decide which pcp freelist and buddy freelist the page should go rather than using get_pfnblock_migratetype() to save some instructions. When there is race between page isolation and free path, we need use additional method to get a accurate value to put the free pages to the correct freelist and get a precise free pages statistics. 2. Use it in page alloc path to update NR_FREE_CMA_PAGES statistics. This patch aims at the scenario 1 and removes two redundant set_freepage_migratetype() calls, which will make sense in the hot path. Signed-off-by: Weijie Yang <[email protected]> --- mm/page_alloc.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 616a2c9..99af01a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -775,7 +775,6 @@ static void __free_pages_ok(struct page *page, unsigned int order) migratetype = get_pfnblock_migratetype(page, pfn); local_irq_save(flags); __count_vm_events(PGFREE, 1 << order); - set_freepage_migratetype(page, migratetype); free_one_page(page_zone(page), page, pfn, order, migratetype); local_irq_restore(flags); } @@ -1024,7 +1023,6 @@ int move_freepages(struct zone *zone, order = page_order(page); list_move(&page->lru, &zone->free_area[order].free_list[migratetype]); - set_freepage_migratetype(page, migratetype); page += 1 << order; pages_moved += 1 << order; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
