6 files changed, 39 insertions, 16 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index ee1c244a62a1..528454c2caa9 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -99,7 +99,11 @@ extern int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 extern int handle_pte_fault(struct mm_struct *mm,
                             struct vm_area_struct *vma, unsigned long address,
                             pte_t *pte, pmd_t *pmd, unsigned int flags);
-extern int split_huge_page(struct page *page);
+extern int split_huge_page_to_list(struct page *page, struct list_head *list);
+static inline int split_huge_page(struct page *page)
+{
+        return split_huge_page_to_list(page, NULL);
+}
 extern void __split_huge_page_pmd(struct vm_area_struct *vma,
                 unsigned long address, pmd_t *pmd);
 #define split_huge_page_pmd(__vma, __address, __pmd)                    \
@@ -186,6 +190,11 @@ extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vm
 #define transparent_hugepage_enabled(__vma) 0
 
 #define transparent_hugepage_flags 0UL
+static inline int
+split_huge_page_to_list(struct page *page, struct list_head *list)
+{
+        return 0;
+}
 static inline int split_huge_page(struct page *page)
 {
         return 0;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b5b12c71a2af..1701ce4be746 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -236,7 +236,7 @@ extern unsigned long nr_free_pagecache_pages(void);
 extern void __lru_cache_add(struct page *, enum lru_list lru);
 extern void lru_cache_add_lru(struct page *, enum lru_list lru);
 extern void lru_add_page_tail(struct page *page, struct page *page_tail,
-                              struct lruvec *lruvec);
+                         struct lruvec *lruvec, struct list_head *head);
 extern void activate_page(struct page *);
 extern void mark_page_accessed(struct page *);
 extern void lru_add_drain(void);
@@ -346,7 +346,7 @@ extern struct address_space swapper_spaces[];
 #define swap_address_space(entry) (&swapper_spaces[swp_type(entry)])
 extern unsigned long total_swapcache_pages(void);
 extern void show_swap_cache_info(void);
-extern int add_to_swap(struct page *);
+extern int add_to_swap(struct page *, struct list_head *list);
 extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
 extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
 extern void __delete_from_swap_cache(struct page *);
@@ -465,7 +465,7 @@ static inline struct page *lookup_swap_cache(swp_entry_t swp)
         return NULL;
 }
 
-static inline int add_to_swap(struct page *page)
+static inline int add_to_swap(struct page *page, struct list_head *list)
 {
         return 0;
 }
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 45eaae030628..2ed1a160a85b 100644
--- 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));
diff --git a/mm/swap.c b/mm/swap.c
index 8a529a01e8fc..acd40bfffa82 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -737,7 +737,7 @@ EXPORT_SYMBOL(__pagevec_release);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 /* used by __split_huge_page_refcount() */
 void lru_add_page_tail(struct page *page, struct page *page_tail,
-                       struct lruvec *lruvec)
+                       struct lruvec *lruvec, struct list_head *list)
 {
         int uninitialized_var(active);
         enum lru_list lru;
@@ -749,7 +749,8 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
         VM_BUG_ON(NR_CPUS != 1 &&
                   !spin_is_locked(&lruvec_zone(lruvec)->lru_lock));
 
-        SetPageLRU(page_tail);
+        if (!list)
+                SetPageLRU(page_tail);
 
         if (page_evictable(page_tail)) {
                 if (PageActive(page)) {
@@ -767,7 +768,11 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
 
         if (likely(PageLRU(page)))
                 list_add_tail(&page_tail->lru, &page->lru);
-        else {
+        else if (list) {
+                /* page reclaim is reclaiming a huge page */
+                get_page(page_tail);
+                list_add_tail(&page_tail->lru, list);
+        } else {
                 struct list_head *list_head;
                 /*
                  * Head page has not yet been counted, as an hpage,
diff --git a/mm/swap_state.c b/mm/swap_state.c
index fe43fd5578cf..b3d40dcf3624 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -160,7 +160,7 @@ void __delete_from_swap_cache(struct page *page)
  * Allocate swap space for the page and add the page to the
  * swap cache.  Caller needs to hold the page lock. 
  */
-int add_to_swap(struct page *page)
+int add_to_swap(struct page *page, struct list_head *list)
 {
         swp_entry_t entry;
         int err;
@@ -173,7 +173,7 @@ int add_to_swap(struct page *page)
                 return 0;
 
         if (unlikely(PageTransHuge(page)))
-                if (unlikely(split_huge_page(page))) {
+                if (unlikely(split_huge_page_to_list(page, list))) {
                         swapcache_free(entry, NULL);
                         return 0;
                 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e53e49584cf3..fa6a85378ee4 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -781,7 +781,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                 if (PageAnon(page) && !PageSwapCache(page)) {
                         if (!(sc->gfp_mask & __GFP_IO))
                                 goto keep_locked;
-                        if (!add_to_swap(page))
+                        if (!add_to_swap(page, page_list))
                                 goto activate_locked;
                         may_enter_fs = 1;
                 }