| Message ID | alpine.LSU.2.11.1805302014001.12558@eggly.anvils (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, May 30, 2018 at 08:23:16PM -0700, Hugh Dickins wrote: > 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. > > 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> Thanks, Hugh.
On Wed, May 30, 2018 at 08:23:16PM -0700, Hugh Dickins wrote: > 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. > > Fixes: 69d763fc6d3a ("mm: pin address_space before dereferencing it while isolating an LRU page") > Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mgorman@techsingularity.net>
--- 4.17-rc7/mm/vmscan.c 2018-04-26 10:48:36.027288294 -0700 +++ linux/mm/vmscan.c 2018-05-30 20:08:39.184634029 -0700 @@ -1418,7 +1418,7 @@ 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;
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. Fixes: 69d763fc6d3a ("mm: pin address_space before dereferencing it while isolating an LRU page") Signed-off-by: Hugh Dickins <hughd@google.com> --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)