[PATCH] fontswap thp fix

[Huang Ying]

---
 mm/page_io.c |  2 +-
 mm/vmscan.c  | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/mm/page_io.c b/mm/page_io.c
index b41cf9644585..6dca817ae7a0 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -250,7 +250,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
 		unlock_page(page);
 		goto out;
 	}
-	if (frontswap_store(page) == 0) {
+	if (!PageTransHuge(page) && frontswap_store(page) == 0) {
 		set_page_writeback(page);
 		unlock_page(page);
 		end_page_writeback(page);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bee53495a829..d1c1e00b08bb 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -55,6 +55,7 @@
 
 #include <linux/swapops.h>
 #include <linux/balloon_compaction.h>
+#include <linux/frontswap.h>
 
 #include "internal.h"
 
@@ -1063,14 +1064,23 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 					/* cannot split THP, skip it */
 					if (!can_split_huge_page(page, NULL))
 						goto activate_locked;
+					/*
+					 * Split THP if frontswap enabled,
+					 * because it cannot process THP
+					 */
+					if (frontswap_enabled()) {
+						if (split_huge_page_to_list(
+							page, page_list))
+							goto activate_locked;
+					}
 					/*
 					 * Split pages without a PMD map right
 					 * away. Chances are some or all of the
 					 * tail pages can be freed without IO.
 					 */
-					if (!compound_mapcount(page) &&
-					    split_huge_page_to_list(page,
-								    page_list))
+					else if (!compound_mapcount(page) &&
+						 split_huge_page_to_list(page,
+							page_list))
 						goto activate_locked;
 				}
 				if (!add_to_swap(page)) {
-- 
2.15.1