4 files changed, 125 insertions, 18 deletions

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 44e7ded33448..5e028870ee8a 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -454,21 +454,27 @@ And if you want disable it again:
 8.2 Type of charges which can be move
 
 Each bits of move_charge_at_immigrate has its own meaning about what type of
-charges should be moved.
+charges should be moved. But in any cases, it must be noted that an account of
+a page or a swap can be moved only when it is charged to the task's current(old)
+memory cgroup.
 
   bit | what type of charges would be moved ?
  -----+------------------------------------------------------------------------
    0  | A charge of an anonymous page(or swap of it) used by the target task.
       | Those pages and swaps must be used only by the target task. You must
       | enable Swap Extension(see 2.4) to enable move of swap charges.
-
-Note: Those pages and swaps must be charged to the old cgroup.
-Note: More type of pages(e.g. file cache, shmem,) will be supported by other
-      bits in future.
+ -----+------------------------------------------------------------------------
+   1  | A charge of file pages(normal file, tmpfs file(e.g. ipc shared memory)
+      | and swaps of tmpfs file) mmaped by the target task. Unlike the case of
+      | anonymous pages, file pages(and swaps) in the range mmapped by the task
+      | will be moved even if the task hasn't done page fault, i.e. they might
+      | not be the task's "RSS", but other task's "RSS" that maps the same file.
+      | And mapcount of the page is ignored(the page can be moved even if
+      | page_mapcount(page) > 1). You must enable Swap Extension(see 2.4) to
+      | enable move of swap charges.
 
 8.3 TODO
 
-- Add support for other types of pages(e.g. file cache, shmem, etc.).
 - Implement madvise(2) to let users decide the vma to be moved or not to be
   moved.
 - All of moving charge operations are done under cgroup_mutex. It's not good
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b6b614364dd8..ff4acea9bbdb 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -282,6 +282,11 @@ extern void kswapd_stop(int nid);
 extern int shmem_unuse(swp_entry_t entry, struct page *page);
 #endif /* CONFIG_MMU */
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+                                        struct page **pagep, swp_entry_t *ent);
+#endif
+
 extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
 
 #ifdef CONFIG_SWAP
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e5277e8a42a8..be5f478351bd 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -250,6 +250,7 @@ struct mem_cgroup {
  */
 enum move_type {
         MOVE_CHARGE_TYPE_ANON,  /* private anonymous page and swap of it */
+        MOVE_CHARGE_TYPE_FILE,  /* file page(including tmpfs) and swap of it */
         NR_MOVE_TYPE,
 };
 
@@ -272,6 +273,12 @@ static bool move_anon(void)
                                         &mc.to->move_charge_at_immigrate);
 }
 
+static bool move_file(void)
+{
+        return test_bit(MOVE_CHARGE_TYPE_FILE,
+                                        &mc.to->move_charge_at_immigrate);
+}
+
 /*
  * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
  * limit reclaim to prevent infinite loops, if they ever occur.
@@ -4179,11 +4186,8 @@ static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
                 /* we don't move shared anon */
                 if (!move_anon() || page_mapcount(page) > 2)
                         return NULL;
-        } else
-                /*
-                 * TODO: We don't move charges of file(including shmem/tmpfs)
-                 * pages for now.
-                 */
+        } else if (!move_file())
+                /* we ignore mapcount for file pages */
                 return NULL;
         if (!get_page_unless_zero(page))
                 return NULL;
@@ -4212,6 +4216,39 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
         return page;
 }
 
+static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
+                        unsigned long addr, pte_t ptent, swp_entry_t *entry)
+{
+        struct page *page = NULL;
+        struct inode *inode;
+        struct address_space *mapping;
+        pgoff_t pgoff;
+
+        if (!vma->vm_file) /* anonymous vma */
+                return NULL;
+        if (!move_file())
+                return NULL;
+
+        inode = vma->vm_file->f_path.dentry->d_inode;
+        mapping = vma->vm_file->f_mapping;
+        if (pte_none(ptent))
+                pgoff = linear_page_index(vma, addr);
+        else /* pte_file(ptent) is true */
+                pgoff = pte_to_pgoff(ptent);
+
+        /* page is moved even if it's not RSS of this task(page-faulted). */
+        if (!mapping_cap_swap_backed(mapping)) { /* normal file */
+                page = find_get_page(mapping, pgoff);
+        } else { /* shmem/tmpfs file. we should take account of swap too. */
+                swp_entry_t ent;
+                mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent);
+                if (do_swap_account)
+                        entry->val = ent.val;
+        }
+
+        return page;
+}
+
 static int is_target_pte_for_mc(struct vm_area_struct *vma,
                 unsigned long addr, pte_t ptent, union mc_target *target)
 {
@@ -4224,7 +4261,8 @@ static int is_target_pte_for_mc(struct vm_area_struct *vma,
                 page = mc_handle_present_pte(vma, addr, ptent);
         else if (is_swap_pte(ptent))
                 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
-        /* TODO: handle swap of shmes/tmpfs */
+        else if (pte_none(ptent) || pte_file(ptent))
+                page = mc_handle_file_pte(vma, addr, ptent, &ent);
 
         if (!page && !ent.val)
                 return 0;
@@ -4285,9 +4323,6 @@ static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
                 };
                 if (is_vm_hugetlb_page(vma))
                         continue;
-                /* TODO: We don't move charges of shmem/tmpfs pages for now. */
-                if (vma->vm_flags & VM_SHARED)
-                        continue;
                 walk_page_range(vma->vm_start, vma->vm_end,
                                         &mem_cgroup_count_precharge_walk);
         }
@@ -4484,9 +4519,6 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
                 };
                 if (is_vm_hugetlb_page(vma))
                         continue;
-                /* TODO: We don't move charges of shmem/tmpfs pages for now. */
-                if (vma->vm_flags & VM_SHARED)
-                        continue;
                 ret = walk_page_range(vma->vm_start, vma->vm_end,
                                                 &mem_cgroup_move_charge_walk);
                 if (ret)
diff --git a/mm/shmem.c b/mm/shmem.c
index 4ef9797bd430..855eaf5b8d5b 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2559,6 +2559,45 @@ out4:
         return error;
 }
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+/**
+ * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
+ * @inode: the inode to be searched
+ * @pgoff: the offset to be searched
+ * @pagep: the pointer for the found page to be stored
+ * @ent: the pointer for the found swap entry to be stored
+ *
+ * If a page is found, refcount of it is incremented. Callers should handle
+ * these refcount.
+ */
+void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+                                        struct page **pagep, swp_entry_t *ent)
+{
+        swp_entry_t entry = { .val = 0 }, *ptr;
+        struct page *page = NULL;
+        struct shmem_inode_info *info = SHMEM_I(inode);
+
+        if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+                goto out;
+
+        spin_lock(&info->lock);
+        ptr = shmem_swp_entry(info, pgoff, NULL);
+#ifdef CONFIG_SWAP
+        if (ptr && ptr->val) {
+                entry.val = ptr->val;
+                page = find_get_page(&swapper_space, entry.val);
+        } else
+#endif
+                page = find_get_page(inode->i_mapping, pgoff);
+        if (ptr)
+                shmem_swp_unmap(ptr);
+        spin_unlock(&info->lock);
+out:
+        *pagep = page;
+        *ent = entry;
+}
+#endif
+
 #else /* !CONFIG_SHMEM */
 
 /*
@@ -2598,6 +2637,31 @@ int shmem_lock(struct file *file, int lock, struct user_struct *user)
         return 0;
 }
 
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+/**
+ * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file
+ * @inode: the inode to be searched
+ * @pgoff: the offset to be searched
+ * @pagep: the pointer for the found page to be stored
+ * @ent: the pointer for the found swap entry to be stored
+ *
+ * If a page is found, refcount of it is incremented. Callers should handle
+ * these refcount.
+ */
+void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
+                                        struct page **pagep, swp_entry_t *ent)
+{
+        struct page *page = NULL;
+
+        if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
+                goto out;
+        page = find_get_page(inode->i_mapping, pgoff);
+out:
+        *pagep = page;
+        *ent = (swp_entry_t){ .val = 0 };
+}
+#endif
+
 #define shmem_vm_ops                            generic_file_vm_ops
 #define shmem_file_operations                   ramfs_file_operations
 #define shmem_get_inode(sb, dir, mode, dev, flags)      ramfs_get_inode(sb, dir, mode, dev)