This is preparation of vmscan for file huge pages. We cannot write out
huge pages, so we need to split them on the way out.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/vmscan.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index c72032dbe8db..9fa9e15594e9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -473,12 +473,14 @@ void drop_slab(void)
static inline int is_page_cache_freeable(struct page *page)
{
+ int radix_tree_pins = PageTransHuge(page) ? HPAGE_PMD_NR : 1;
+
/*
* A freeable page cache page is referenced only by the caller
* that isolated the page, the page cache radix tree and
* optional buffer heads at page->private.
*/
- return page_count(page) - page_has_private(page) == 2;
+ return page_count(page) - page_has_private(page) == 1 + radix_tree_pins;
}
static int may_write_to_inode(struct inode *inode, struct scan_control *sc)
@@ -548,8 +550,6 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
* swap_backing_dev_info is bust: it doesn't reflect the
* congestion state of the swapdevs. Easy to fix, if needed.
*/
- if (!is_page_cache_freeable(page))
- return PAGE_KEEP;
if (!mapping) {
/*
* Some data journaling orphaned pages can have
@@ -1112,6 +1112,15 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* starts and then write it out here.
*/
try_to_unmap_flush_dirty();
+
+ if (!is_page_cache_freeable(page))
+ goto keep_locked;
+
+ if (unlikely(PageTransHuge(page))) {
+ if (split_huge_page_to_list(page, page_list))
+ goto keep_locked;
+ }
+
switch (pageout(page, mapping, sc)) {
case PAGE_KEEP:
goto keep_locked;
--
2.7.0
--
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