4.4-stable review patch. If anyone has any objections, please let me know.
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From: Hugh Dickins hughd@google.com
commit 145e1a71e090575c74969e3daa8136d1e5b99fc8 upstream.
George Boole would have noticed a slight error in 4.16 commit 69d763fc6d3a ("mm: pin address_space before dereferencing it while isolating an LRU page"). Fix it, to match both the comment above it, and the original behaviour.
Although anonymous pages are not marked PageDirty at first, we have an old habit of calling SetPageDirty when a page is removed from swap cache: so there's a category of ex-swap pages that are easily migratable, but were inadvertently excluded from compaction's async migration in 4.16.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1805302014001.12558@eggly.anvils Fixes: 69d763fc6d3a ("mm: pin address_space before dereferencing it while isolating an LRU page") Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Minchan Kim minchan@kernel.org Acked-by: Mel Gorman mgorman@techsingularity.net Reported-by: Ivan Kalvachev ikalvachev@gmail.com Cc: "Huang, Ying" ying.huang@intel.com Cc: Jan Kara jack@suse.cz Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1331,7 +1331,7 @@ int __isolate_lru_page(struct page *page return ret;
mapping = page_mapping(page); - migrate_dirty = mapping && mapping->a_ops->migratepage; + migrate_dirty = !mapping || mapping->a_ops->migratepage; unlock_page(page); if (!migrate_dirty) return ret;