when we test the pages in a range is free or not, there is a little chance we encounter some page which is not in buddy but page_count is 0. That means that page could be in the page-freeing path but not in the buddy freelist, such as in pcplist or wait for the zone->lock which the tester is holding.
Back to the freepage_migratetype, we use it for a cached value for decide which free-list the page go when freeing page. If the pageblock is isolated the page will go to free-list[MIGRATE_ISOLATE] even if the cached type is not MIGRATE_ISOLATE, the commit ad53f92e(fix incorrect isolation behavior by rechecking migratetype) patch series have ensure this. So the freepage_migratetype check for page_count==0 page in __test_page_isolated_in_pageblock() is meaningless. This patch removes the unnecessary freepage_migratetype check. Signed-off-by: Weijie Yang <weijie.y...@samsung.com> --- mm/page_isolation.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 6e5174d..f7c9183 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -223,8 +223,7 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, page = pfn_to_page(pfn); if (PageBuddy(page)) pfn += 1 << page_order(page); - else if (page_count(page) == 0 && - get_freepage_migratetype(page) == MIGRATE_ISOLATE) + else if (page_count(page) == 0) pfn += 1; else if (skip_hwpoisoned_pages && PageHWPoison(page)) { /* -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/