2.6.25-git19

 mm

diff --git a/mm/shmem.c b/mm/shmem.c
index f514dd3..e2a6ae1 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -201,7 +201,7 @@ static struct vm_operations_struct shmem_vm_ops;
 
 static struct backing_dev_info shmem_backing_dev_info  __read_mostly = {
    .ra_pages   = 0,   /* No readahead */
-   .capabilities   = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+   .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
    .unplug_io_fn   = default_unplug_io_fn,
 };
 
@@ -1079,104 +1079,47 @@ redirty:
 
 #ifdef CONFIG_NUMA
 #ifdef CONFIG_TMPFS
-static int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes)
+static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
 {
-   char *nodelist = strchr(value, ':');
-   int err = 1;
+   char buffer[64];
 
-   if (nodelist) {
-      /* NUL-terminate policy string */
-      *nodelist++ = '\0';
-      if (nodelist_parse(nodelist, *policy_nodes))
-         goto out;
-      if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY]))
-         goto out;
-   }
-   if (!strcmp(value, "default")) {
-      *policy = MPOL_DEFAULT;
-      /* Don't allow a nodelist */
-      if (!nodelist)
-         err = 0;
-   } else if (!strcmp(value, "prefer")) {
-      *policy = MPOL_PREFERRED;
-      /* Insist on a nodelist of one node only */
-      if (nodelist) {
-         char *rest = nodelist;
-         while (isdigit(*rest))
-            rest++;
-         if (!*rest)
-            err = 0;
-      }
-   } else if (!strcmp(value, "bind")) {
-      *policy = MPOL_BIND;
-      /* Insist on a nodelist */
-      if (nodelist)
-         err = 0;
-   } else if (!strcmp(value, "interleave")) {
-      *policy = MPOL_INTERLEAVE;
-      /*
-       * Default to online nodes with memory if no nodelist
-       */
-      if (!nodelist)
-         *policy_nodes = node_states[N_HIGH_MEMORY];
-      err = 0;
-   }
-out:
-   /* Restore string for error message */
-   if (nodelist)
-      *--nodelist = ':';
-   return err;
-}
-
-static void shmem_show_mpol(struct seq_file *seq, int policy,
-             const nodemask_t policy_nodes)
-{
-   char *policy_string;
+   if (!mpol || mpol->mode == MPOL_DEFAULT)
+      return;      /* show nothing */
 
-   switch (policy) {
-   case MPOL_PREFERRED:
-      policy_string = "prefer";
-      break;
-   case MPOL_BIND:
-      policy_string = "bind";
-      break;
-   case MPOL_INTERLEAVE:
-      policy_string = "interleave";
-      break;
-   default:
-      /* MPOL_DEFAULT */
-      return;
-   }
+   mpol_to_str(buffer, sizeof(buffer), mpol, 1);
 
-   seq_printf(seq, ",mpol=%s", policy_string);
-
-   if (policy != MPOL_INTERLEAVE ||
-       !nodes_equal(policy_nodes, node_states[N_HIGH_MEMORY])) {
-      char buffer[64];
-      int len;
+   seq_printf(seq, ",mpol=%s", buffer);
+}
 
-      len = nodelist_scnprintf(buffer, sizeof(buffer), policy_nodes);
-      if (len < sizeof(buffer))
-         seq_printf(seq, ":%s", buffer);
-      else
-         seq_printf(seq, ":?");
+static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+{
+   struct mempolicy *mpol = NULL;
+   if (sbinfo->mpol) {
+      spin_lock(&sbinfo->stat_lock);   /* prevent replace/use races */
+      mpol = sbinfo->mpol;
+      mpol_get(mpol);
+      spin_unlock(&sbinfo->stat_lock);
    }
+   return mpol;
 }
 #endif /* CONFIG_TMPFS */
 
 static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
          struct shmem_inode_info *info, unsigned long idx)
 {
+   struct mempolicy mpol, *spol;
    struct vm_area_struct pvma;
    struct page *page;
 
+   spol = mpol_cond_copy(&mpol,
+            mpol_shared_policy_lookup(&info->policy, idx));
+
    /* Create a pseudo vma that just contains the policy */
    pvma.vm_start = 0;
    pvma.vm_pgoff = idx;
    pvma.vm_ops = NULL;
-   pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
+   pvma.vm_policy = spol;
    page = swapin_readahead(entry, gfp, &pvma, 0);
-   mpol_free(pvma.vm_policy);
    return page;
 }
 
@@ -1184,27 +1127,21 @@ static struct page *shmem_alloc_page(gfp_t gfp,
          struct shmem_inode_info *info, unsigned long idx)
 {
    struct vm_area_struct pvma;
-   struct page *page;
 
    /* Create a pseudo vma that just contains the policy */
    pvma.vm_start = 0;
    pvma.vm_pgoff = idx;
    pvma.vm_ops = NULL;
    pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
-   page = alloc_page_vma(gfp, &pvma, 0);
-   mpol_free(pvma.vm_policy);
-   return page;
+
+   /*
+    * alloc_page_vma() will drop the shared policy reference
+    */
+   return alloc_page_vma(gfp, &pvma, 0);
 }
 #else /* !CONFIG_NUMA */
 #ifdef CONFIG_TMPFS
-static inline int shmem_parse_mpol(char *value, int *policy,
-                  nodemask_t *policy_nodes)
-{
-   return 1;
-}
-
-static inline void shmem_show_mpol(struct seq_file *seq, int policy,
-             const nodemask_t policy_nodes)
+static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
 {
 }
 #endif /* CONFIG_TMPFS */
@@ -1222,6 +1159,13 @@ static inline struct page *shmem_alloc_page(gfp_t gfp,
 }
 #endif /* CONFIG_NUMA */
 
+#if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
+static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
+{
+   return NULL;
+}
+#endif
+
 /*
  * shmem_getpage - either get the page from swap or allocate a new one
  *
@@ -1576,8 +1520,8 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
       case S_IFREG:
          inode->i_op = &shmem_inode_operations;
          inode->i_fop = &shmem_file_operations;
-         mpol_shared_policy_init(&info->policy, sbinfo->policy,
-                     &sbinfo->policy_nodes);
+         mpol_shared_policy_init(&info->policy,
+                   shmem_get_sbmpol(sbinfo));
          break;
       case S_IFDIR:
          inc_nlink(inode);
@@ -1591,8 +1535,7 @@ shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
           * Must not load anything in the rbtree,
           * mpol_free_shared_policy will not be called.
           */
-         mpol_shared_policy_init(&info->policy, MPOL_DEFAULT,
-                  NULL);
+         mpol_shared_policy_init(&info->policy, NULL);
          break;
       }
    } else
@@ -2207,8 +2150,7 @@ static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
          if (*rest)
             goto bad_val;
       } else if (!strcmp(this_char,"mpol")) {
-         if (shmem_parse_mpol(value, &sbinfo->policy,
-                    &sbinfo->policy_nodes))
+         if (mpol_parse_str(value, &sbinfo->mpol, 1))
             goto bad_val;
       } else {
          printk(KERN_ERR "tmpfs: Bad mount option %s\n",
@@ -2259,8 +2201,9 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
    sbinfo->free_blocks = config.max_blocks - blocks;
    sbinfo->max_inodes  = config.max_inodes;
    sbinfo->free_inodes = config.max_inodes - inodes;
-   sbinfo->policy      = config.policy;
-   sbinfo->policy_nodes = config.policy_nodes;
+
+   mpol_put(sbinfo->mpol);
+   sbinfo->mpol        = config.mpol;   /* transfers initial ref */
 out:
    spin_unlock(&sbinfo->stat_lock);
    return error;
@@ -2281,7 +2224,7 @@ static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
       seq_printf(seq, ",uid=%u", sbinfo->uid);
    if (sbinfo->gid != 0)
       seq_printf(seq, ",gid=%u", sbinfo->gid);
-   shmem_show_mpol(seq, sbinfo->policy, sbinfo->policy_nodes);
+   shmem_show_mpol(seq, sbinfo->mpol);
    return 0;
 }
 #endif /* CONFIG_TMPFS */
@@ -2311,8 +2254,7 @@ static int shmem_fill_super(struct super_block *sb,
    sbinfo->mode = S_IRWXUGO | S_ISVTX;
    sbinfo->uid = current->fsuid;
    sbinfo->gid = current->fsgid;
-   sbinfo->policy = MPOL_DEFAULT;
-   sbinfo->policy_nodes = node_states[N_HIGH_MEMORY];
+   sbinfo->mpol = NULL;
    sb->s_fs_info = sbinfo;
 
 #ifdef CONFIG_TMPFS