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 ttu at the moment.
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
include/linux/rmap.h | 1 -
mm/rmap.c | 6 +++---
mm/vmscan.c | 3 ---
3 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index fee10d7..b556eef 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -298,6 +298,5 @@ static inline int page_mkclean(struct page *page)
#define SWAP_AGAIN 1
#define SWAP_FAIL 2
#define SWAP_MLOCK 3
-#define SWAP_DIRTY 4
#endif /* _LINUX_RMAP_H */
diff --git a/mm/rmap.c b/mm/rmap.c
index 9dbfa6f..d47af09 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1414,7 +1414,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
*/
if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) {
WARN_ON_ONCE(1);
- ret = SWAP_FAIL;
+ ret = false;
page_vma_mapped_walk_done(&pvmw);
break;
}
@@ -1431,7 +1431,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* discarded. Remap the page to page table.
*/
set_pte_at(mm, address, pvmw.pte, pteval);
- ret = SWAP_DIRTY;
+ SetPageSwapBacked(page);
+ ret = SWAP_FAIL;
page_vma_mapped_walk_done(&pvmw);
break;
}
@@ -1501,7 +1502,6 @@ static int page_mapcount_is_zero(struct page *page)
* SWAP_AGAIN - we missed a mapping, try again later
* SWAP_FAIL - the page is unswappable
* SWAP_MLOCK - page is mlocked.
- * SWAP_DIRTY - page is dirty MADV_FREE page
*/
int try_to_unmap(struct page *page, enum ttu_flags flags)
{
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a3656f9..b8fd656 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1142,9 +1142,6 @@ 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;
--
2.7.4
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