1 files changed, 38 insertions, 27 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index ebee81688736..869aaa3206a2 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -49,6 +49,7 @@
 #include <linux/swapops.h>
 #include <linux/slab.h>
 #include <linux/init.h>
+#include <linux/ksm.h>
 #include <linux/rmap.h>
 #include <linux/rcupdate.h>
 #include <linux/module.h>
@@ -336,9 +337,9 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
  * Subfunctions of page_referenced: page_referenced_one called
  * repeatedly from either page_referenced_anon or page_referenced_file.
  */
-static int page_referenced_one(struct page *page, struct vm_area_struct *vma,
-                               unsigned long address, unsigned int *mapcount,
-                               unsigned long *vm_flags)
+int page_referenced_one(struct page *page, struct vm_area_struct *vma,
+                        unsigned long address, unsigned int *mapcount,
+                        unsigned long *vm_flags)
 {
         struct mm_struct *mm = vma->vm_mm;
         pte_t *pte;
@@ -507,28 +508,33 @@ int page_referenced(struct page *page,
                     unsigned long *vm_flags)
 {
         int referenced = 0;
+        int we_locked = 0;
 
         if (TestClearPageReferenced(page))
                 referenced++;
 
         *vm_flags = 0;
         if (page_mapped(page) && page_rmapping(page)) {
-                if (PageAnon(page))
+                if (!is_locked && (!PageAnon(page) || PageKsm(page))) {
+                        we_locked = trylock_page(page);
+                        if (!we_locked) {
+                                referenced++;
+                                goto out;
+                        }
+                }
+                if (unlikely(PageKsm(page)))
+                        referenced += page_referenced_ksm(page, mem_cont,
+                                                                vm_flags);
+                else if (PageAnon(page))
                         referenced += page_referenced_anon(page, mem_cont,
                                                                 vm_flags);
-                else if (is_locked)
+                else if (page->mapping)
                         referenced += page_referenced_file(page, mem_cont,
                                                                 vm_flags);
-                else if (!trylock_page(page))
-                        referenced++;
-                else {
-                        if (page->mapping)
-                                referenced += page_referenced_file(page,
-                                                        mem_cont, vm_flags);
+                if (we_locked)
                         unlock_page(page);
-                }
         }
-
+out:
         if (page_test_and_clear_young(page))
                 referenced++;
 
@@ -620,14 +626,7 @@ static void __page_set_anon_rmap(struct page *page,
         BUG_ON(!anon_vma);
         anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
         page->mapping = (struct address_space *) anon_vma;
-
         page->index = linear_page_index(vma, address);
-
-        /*
-         * nr_mapped state can be updated without turning off
-         * interrupts because it is not modified via interrupt.
-         */
-        __inc_zone_page_state(page, NR_ANON_PAGES);
 }
 
 /**
@@ -665,14 +664,21 @@ static void __page_check_anon_rmap(struct page *page,
  * @vma:        the vm area in which the mapping is added
  * @address:    the user virtual address mapped
  *
- * The caller needs to hold the pte lock and the page must be locked.
+ * The caller needs to hold the pte lock, and the page must be locked in
+ * the anon_vma case: to serialize mapping,index checking after setting.
  */
 void page_add_anon_rmap(struct page *page,
         struct vm_area_struct *vma, unsigned long address)
 {
+        int first = atomic_inc_and_test(&page->_mapcount);
+        if (first)
+                __inc_zone_page_state(page, NR_ANON_PAGES);
+        if (unlikely(PageKsm(page)))
+                return;
+
         VM_BUG_ON(!PageLocked(page));
         VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
-        if (atomic_inc_and_test(&page->_mapcount))
+        if (first)
                 __page_set_anon_rmap(page, vma, address);
         else
                 __page_check_anon_rmap(page, vma, address);
@@ -694,6 +700,7 @@ void page_add_new_anon_rmap(struct page *page,
         VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
         SetPageSwapBacked(page);
         atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */
+        __inc_zone_page_state(page, NR_ANON_PAGES);
         __page_set_anon_rmap(page, vma, address);
         if (page_evictable(page, vma))
                 lru_cache_add_lru(page, LRU_ACTIVE_ANON);
@@ -760,8 +767,8 @@ void page_remove_rmap(struct page *page)
  * Subfunctions of try_to_unmap: try_to_unmap_one called
  * 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,
-                            unsigned long address, enum ttu_flags flags)
+int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
+                     unsigned long address, enum ttu_flags flags)
 {
         struct mm_struct *mm = vma->vm_mm;
         pte_t *pte;
@@ -1156,7 +1163,9 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
 
         BUG_ON(!PageLocked(page));
 
-        if (PageAnon(page))
+        if (unlikely(PageKsm(page)))
+                ret = try_to_unmap_ksm(page, flags);
+        else if (PageAnon(page))
                 ret = try_to_unmap_anon(page, flags);
         else
                 ret = try_to_unmap_file(page, flags);
@@ -1177,15 +1186,17 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
  *
  * SWAP_AGAIN   - no vma is holding page mlocked, or,
  * SWAP_AGAIN   - page mapped in mlocked vma -- couldn't acquire mmap sem
+ * SWAP_FAIL    - page cannot be located at present
  * SWAP_MLOCK   - page is now mlocked.
  */
 int try_to_munlock(struct page *page)
 {
         VM_BUG_ON(!PageLocked(page) || PageLRU(page));
 
-        if (PageAnon(page))
+        if (unlikely(PageKsm(page)))
+                return try_to_unmap_ksm(page, TTU_MUNLOCK);
+        else if (PageAnon(page))
                 return try_to_unmap_anon(page, TTU_MUNLOCK);
         else
                 return try_to_unmap_file(page, TTU_MUNLOCK);
 }
-