4 files changed, 36 insertions, 21 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 8dff2ffab82c..4c4a2d4d289e 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -85,7 +85,18 @@ static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma,
  */
 int page_referenced(struct page *, int is_locked,
                         struct mem_cgroup *cnt, unsigned long *vm_flags);
-int try_to_unmap(struct page *, int ignore_refs);
+enum ttu_flags {
+        TTU_UNMAP = 0,                  /* unmap mode */
+        TTU_MIGRATION = 1,              /* migration mode */
+        TTU_MUNLOCK = 2,                /* munlock mode */
+        TTU_ACTION_MASK = 0xff,
+
+        TTU_IGNORE_MLOCK = (1 << 8),    /* ignore mlock */
+        TTU_IGNORE_ACCESS = (1 << 9),   /* don't age */
+};
+#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
+
+int try_to_unmap(struct page *, enum ttu_flags flags);
 
 /*
  * Called from mm/filemap_xip.c to unmap empty zero page
diff --git a/mm/migrate.c b/mm/migrate.c
index 939888f9ddab..e3a0cd3859a9 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -669,7 +669,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
         }
 
         /* Establish migration ptes or remove ptes */
-        try_to_unmap(page, 1);
+        try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
 
         if (!page_mapped(page))
                 rc = move_to_new_page(newpage, page);
diff --git a/mm/rmap.c b/mm/rmap.c
index 5a35c030e779..08c112a776a7 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -774,7 +774,7 @@ void page_remove_rmap(struct page *page)
  * repeatedly from either try_to_unmap_anon or try_to_unmap_file.
  */
 static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
-                                int migration)
+                                enum ttu_flags flags)
 {
         struct mm_struct *mm = vma->vm_mm;
         unsigned long address;
@@ -796,11 +796,13 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
          * If it's recently referenced (perhaps page_referenced
          * skipped over this mm) then we should reactivate it.
          */
-        if (!migration) {
+        if (!(flags & TTU_IGNORE_MLOCK)) {
                 if (vma->vm_flags & VM_LOCKED) {
                         ret = SWAP_MLOCK;
                         goto out_unmap;
                 }
+        }
+        if (!(flags & TTU_IGNORE_ACCESS)) {
                 if (ptep_clear_flush_young_notify(vma, address, pte)) {
                         ret = SWAP_FAIL;
                         goto out_unmap;
@@ -840,12 +842,12 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                          * pte. do_swap_page() will wait until the migration
                          * pte is removed and then restart fault handling.
                          */
-                        BUG_ON(!migration);
+                        BUG_ON(TTU_ACTION(flags) != TTU_MIGRATION);
                         entry = make_migration_entry(page, pte_write(pteval));
                 }
                 set_pte_at(mm, address, pte, swp_entry_to_pte(entry));
                 BUG_ON(pte_file(*pte));
-        } else if (PAGE_MIGRATION && migration) {
+        } else if (PAGE_MIGRATION && (TTU_ACTION(flags) == TTU_MIGRATION)) {
                 /* Establish migration entry for a file page */
                 swp_entry_t entry;
                 entry = make_migration_entry(page, pte_write(pteval));
@@ -1014,12 +1016,13 @@ static int try_to_mlock_page(struct page *page, struct vm_area_struct *vma)
  * vm_flags for that VMA.  That should be OK, because that vma shouldn't be
  * 'LOCKED.
  */
-static int try_to_unmap_anon(struct page *page, int unlock, int migration)
+static int try_to_unmap_anon(struct page *page, enum ttu_flags flags)
 {
         struct anon_vma *anon_vma;
         struct vm_area_struct *vma;
         unsigned int mlocked = 0;
         int ret = SWAP_AGAIN;
+        int unlock = TTU_ACTION(flags) == TTU_MUNLOCK;
 
         if (MLOCK_PAGES && unlikely(unlock))
                 ret = SWAP_SUCCESS;     /* default for try_to_munlock() */
@@ -1035,7 +1038,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
                                 continue;  /* must visit all unlocked vmas */
                         ret = SWAP_MLOCK;  /* saw at least one mlocked vma */
                 } else {
-                        ret = try_to_unmap_one(page, vma, migration);
+                        ret = try_to_unmap_one(page, vma, flags);
                         if (ret == SWAP_FAIL || !page_mapped(page))
                                 break;
                 }
@@ -1059,8 +1062,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
 /**
  * try_to_unmap_file - unmap/unlock file page using the object-based rmap method
  * @page: the page to unmap/unlock
- * @unlock:  request for unlock rather than unmap [unlikely]
- * @migration:  unmapping for migration - ignored if @unlock
+ * @flags: action and flags
  *
  * Find all the mappings of a page using the mapping pointer and the vma chains
  * contained in the address_space struct it points to.
@@ -1072,7 +1074,7 @@ static int try_to_unmap_anon(struct page *page, int unlock, int migration)
  * vm_flags for that VMA.  That should be OK, because that vma shouldn't be
  * 'LOCKED.
  */
-static int try_to_unmap_file(struct page *page, int unlock, int migration)
+static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
 {
         struct address_space *mapping = page->mapping;
         pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -1084,6 +1086,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
         unsigned long max_nl_size = 0;
         unsigned int mapcount;
         unsigned int mlocked = 0;
+        int unlock = TTU_ACTION(flags) == TTU_MUNLOCK;
 
         if (MLOCK_PAGES && unlikely(unlock))
                 ret = SWAP_SUCCESS;     /* default for try_to_munlock() */
@@ -1096,7 +1099,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
                                 continue;       /* must visit all vmas */
                         ret = SWAP_MLOCK;
                 } else {
-                        ret = try_to_unmap_one(page, vma, migration);
+                        ret = try_to_unmap_one(page, vma, flags);
                         if (ret == SWAP_FAIL || !page_mapped(page))
                                 goto out;
                 }
@@ -1121,7 +1124,8 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
                         ret = SWAP_MLOCK;       /* leave mlocked == 0 */
                         goto out;               /* no need to look further */
                 }
-                if (!MLOCK_PAGES && !migration && (vma->vm_flags & VM_LOCKED))
+                if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
+                        (vma->vm_flags & VM_LOCKED))
                         continue;
                 cursor = (unsigned long) vma->vm_private_data;
                 if (cursor > max_nl_cursor)
@@ -1155,7 +1159,7 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration)
         do {
                 list_for_each_entry(vma, &mapping->i_mmap_nonlinear,
                                                 shared.vm_set.list) {
-                        if (!MLOCK_PAGES && !migration &&
+                        if (!MLOCK_PAGES && !(flags & TTU_IGNORE_MLOCK) &&
                             (vma->vm_flags & VM_LOCKED))
                                 continue;
                         cursor = (unsigned long) vma->vm_private_data;
@@ -1195,7 +1199,7 @@ out:
 /**
  * try_to_unmap - try to remove all page table mappings to a page
  * @page: the page to get unmapped
- * @migration: migration flag
+ * @flags: action and flags
  *
  * Tries to remove all the page table entries which are mapping this
  * page, used in the pageout path.  Caller must hold the page lock.
@@ -1206,16 +1210,16 @@ out:
  * SWAP_FAIL    - the page is unswappable
  * SWAP_MLOCK   - page is mlocked.
  */
-int try_to_unmap(struct page *page, int migration)
+int try_to_unmap(struct page *page, enum ttu_flags flags)
 {
         int ret;
 
         BUG_ON(!PageLocked(page));
 
         if (PageAnon(page))
-                ret = try_to_unmap_anon(page, 0, migration);
+                ret = try_to_unmap_anon(page, flags);
         else
-                ret = try_to_unmap_file(page, 0, migration);
+                ret = try_to_unmap_file(page, flags);
         if (ret != SWAP_MLOCK && !page_mapped(page))
                 ret = SWAP_SUCCESS;
         return ret;
@@ -1240,8 +1244,8 @@ int try_to_munlock(struct page *page)
         VM_BUG_ON(!PageLocked(page) || PageLRU(page));
 
         if (PageAnon(page))
-                return try_to_unmap_anon(page, 1, 0);
+                return try_to_unmap_anon(page, TTU_MUNLOCK);
         else
-                return try_to_unmap_file(page, 1, 0);
+                return try_to_unmap_file(page, TTU_MUNLOCK);
 }
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ba8228e0a806..ab3b0ad3ce52 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -659,7 +659,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                  * processes. Try to unmap it here.
                  */
                 if (page_mapped(page) && mapping) {
-                        switch (try_to_unmap(page, 0)) {
+                        switch (try_to_unmap(page, TTU_UNMAP)) {
                         case SWAP_FAIL:
                                 goto activate_locked;
                         case SWAP_AGAIN: