From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/page_isolation: drop WARN_ON_ONCE() in set_migratetype_isolate() Inside has_unmovable_pages(), we have a comment describing how unmovable data could end up in ZONE_MOVABLE - via "movablecore". Also, besides checking if the first page in the pageblock is reserved, we don't perform any further checks in case of ZONE_MOVABLE. In case of memory offlining, we set REPORT_FAILURE, properly dump_page() the page and handle the error gracefully. alloc_contig_pages() users currently never allocate from ZONE_MOVABLE. E.g., hugetlb uses alloc_contig_pages() for the allocation of gigantic pages only, which will never end up on the MOVABLE zone (see htlb_alloc_mask()). Link: http://lkml.kernel.org/r/20200816125333.7434-4-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Michael S. Tsirkin <mst@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx> Cc: Jason Wang <jasowang@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_isolation.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) --- a/mm/page_isolation.c~mm-page_isolation-drop-warn_on_once-in-set_migratetype_isolate +++ a/mm/page_isolation.c @@ -57,15 +57,12 @@ static int set_migratetype_isolate(struc spin_unlock_irqrestore(&zone->lock, flags); if (!ret) { drain_all_pages(zone); - } else { - WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE); - - if ((isol_flags & REPORT_FAILURE) && unmovable) - /* - * printk() with zone->lock held will likely trigger a - * lockdep splat, so defer it here. - */ - dump_page(unmovable, "unmovable page"); + } else if ((isol_flags & REPORT_FAILURE) && unmovable) { + /* + * printk() with zone->lock held will likely trigger a + * lockdep splat, so defer it here. + */ + dump_page(unmovable, "unmovable page"); } return ret; _
