unset_migratetype_isolate() already validates under zone lock that a given page has already been isolated as MIGRATE_ISOLATE. There is no need for another check before. Hence just drop this redundant validation. Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linux-mm@xxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- Is there any particular reason to do this migratetype pre-check without zone lock before calling unsert_migrate_isolate() ? If not this should be removed. mm/page_isolation.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_isolation.c b/mm/page_isolation.c index e3638a5bafff..f529d250c8a5 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -243,7 +243,7 @@ int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, pfn < end_pfn; pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); - if (!page || !is_migrate_isolate_page(page)) + if (!page) continue; unset_migratetype_isolate(page, migratetype); } -- 2.20.1