mm: remove SWAP_DIRTY in ttu

If we found lazyfree page is dirty, try_to_unmap_one can just
SetPageSwapBakced in there like PG_mlocked page and just return with
SWAP_FAIL which is very natural because the page is not swappable right
now so that vmscan can activate it.  There is no point to introduce new
return value SWAP_DIRTY in try_to_unmap at the moment.

Link: http://lkml.kernel.org/r/1489555493-14659-3-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 3 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index e54c882d6789..f1fd388454bd 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1147,9 +1147,6 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		if (page_mapped(page)) {
 			switch (ret = try_to_unmap(page,
 				ttu_flags | TTU_BATCH_FLUSH)) {
-			case SWAP_DIRTY:
-				SetPageSwapBacked(page);
-				/* fall through */
 			case SWAP_FAIL:
 				nr_unmap_fail++;
 				goto activate_locked;