mm: thp: add split tail pages to shrink page list in page reclaim

[deliverable/linux.git] / mm / huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 45eaae03062805899f559399691b42ca9554d829..2ed1a160a85ba5c1351fbe2122b6380689b22e95 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1559,7 +1559,8 @@ static int __split_huge_page_splitting(struct page *page,
        return ret;
 }
 
-static void __split_huge_page_refcount(struct page *page)
+static void __split_huge_page_refcount(struct page *page,
+                                      struct list_head *list)
 {
        int i;
        struct zone *zone = page_zone(page);
@@ -1645,7 +1646,7 @@ static void __split_huge_page_refcount(struct page *page)
                BUG_ON(!PageDirty(page_tail));
                BUG_ON(!PageSwapBacked(page_tail));
 
-               lru_add_page_tail(page, page_tail, lruvec);
+               lru_add_page_tail(page, page_tail, lruvec, list);
        }
        atomic_sub(tail_count, &page->_count);
        BUG_ON(atomic_read(&page->_count) <= 0);
@@ -1752,7 +1753,8 @@ static int __split_huge_page_map(struct page *page,
 
 /* must be called with anon_vma->root->rwsem held */
 static void __split_huge_page(struct page *page,
-                             struct anon_vma *anon_vma)
+                             struct anon_vma *anon_vma,
+                             struct list_head *list)
 {
        int mapcount, mapcount2;
        pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -1783,7 +1785,7 @@ static void __split_huge_page(struct page *page,
                       mapcount, page_mapcount(page));
        BUG_ON(mapcount != page_mapcount(page));
 
-       __split_huge_page_refcount(page);
+       __split_huge_page_refcount(page, list);
 
        mapcount2 = 0;
        anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) {
@@ -1798,7 +1800,14 @@ static void __split_huge_page(struct page *page,
        BUG_ON(mapcount != mapcount2);
 }
 
-int split_huge_page(struct page *page)
+/*
+ * Split a hugepage into normal pages. This doesn't change the position of head
+ * page. If @list is null, tail pages will be added to LRU list, otherwise, to
+ * @list. Both head page and tail pages will inherit mapping, flags, and so on
+ * from the hugepage.
+ * Return 0 if the hugepage is split successfully otherwise return 1.
+ */
+int split_huge_page_to_list(struct page *page, struct list_head *list)
 {
        struct anon_vma *anon_vma;
        int ret = 1;
@@ -1823,7 +1832,7 @@ int split_huge_page(struct page *page)
                goto out_unlock;
 
        BUG_ON(!PageSwapBacked(page));
-       __split_huge_page(page, anon_vma);
+       __split_huge_page(page, anon_vma, list);
        count_vm_event(THP_SPLIT);
 
        BUG_ON(PageCompound(page));