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authorHugh Dickins <hughd@google.com>2018-06-01 16:50:50 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-05 11:46:14 +0200
commit4f6597fb03344ced4a8ca4931f3026e3eb76cada (patch)
tree272ffbafadc7aed296b1c738a39cb159b879aa38
parent3035e187f397edaf81de0d859bff7c6bc26057c8 (diff)
mm: fix the NULL mapping case in __isolate_lru_page()
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>
-rw-r--r--mm/vmscan.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a47621fa8496..f9ae07ef5ce8 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1392,7 +1392,7 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
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;