The patch titled Subject: mm/vmscan.c: add warn on inadvertently reclaiming mapped page has been removed from the -mm tree. Its filename was mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page.patch This patch was dropped because it was nacked ------------------------------------------------------ From: Hillf Danton <hdanton@xxxxxxxx> Subject: mm/vmscan.c: add warn on inadvertently reclaiming mapped page In isolate_lru_pages(), we check scan_control::may_unmap and set isolation mode accordingly in order to not isolate from the lru list any page that does not match the isolation mode. For example, we should skip all sill mapped pages if isolation mode is set to be ISOLATE_UNMAPPED. So complain, while scanning the isolated pages, about the very unlikely event that we hit a mapped page that we should never have isolated. Note no change is added in the current scanning behavior without VM debug configured. And cut off one line of comment that goes stale. Link: http://lkml.kernel.org/r/20190526062353.14684-1-hdanton@xxxxxxxx Signed-off-by: Hillf Danton <hdanton@xxxxxxxx> Reviewed-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/mm/vmscan.c~mm-vmscan-add-warn-on-inadvertently-reclaiming-mapped-page +++ a/mm/vmscan.c @@ -1138,8 +1138,10 @@ static unsigned long shrink_page_list(st if (unlikely(!page_evictable(page))) goto activate_locked; - if (!sc->may_unmap && page_mapped(page)) + if (!sc->may_unmap && page_mapped(page)) { + VM_WARN_ON(true); goto keep_locked; + } may_enter_fs = (sc->gfp_mask & __GFP_FS) || (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO)); @@ -1657,7 +1659,6 @@ static __always_inline void update_lru_s * @dst: The temp list to put pages on to. * @nr_scanned: The number of pages that were scanned. * @sc: The scan_control struct for this reclaim session - * @mode: One of the LRU isolation modes * @lru: LRU list id for isolating * * returns how many pages were moved onto *@dst. _ Patches currently in -mm which might be from hdanton@xxxxxxxx are