On Wed, Nov 7, 2012 at 6:24 AM, David Sterba [off-list ref] wrote:

On Mon, Oct 29, 2012 at 12:30:44PM +0800, zwu.kernel@gmail.com wrote:

quoted

+/* Frees the entire hot_range_tree. */
+static void hot_inode_item_free(struct kref *kref)
+{
+     struct hot_comm_item *comm_item = container_of(kref,
+                     struct hot_comm_item, refs);
+     struct hot_inode_item *he = container_of(comm_item,
+                     struct hot_inode_item, hot_inode);
+
+     hot_range_tree_free(he);
+     radix_tree_delete(he->hot_inode_tree, he->i_ino);

void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)

and he::i_ino is u64, this will not work when
sizeof(unsigned long) != sizeof(u64) (iirc this is a known limitation of
radix tree implementation). This will work on 64bit only, not sure if
this is intentional.

Fixed, thanks.

quoted

+     kmem_cache_free(hot_inode_item_cachep, he);
+}
+
+/* Frees the entire hot_inode_tree. */
+static void hot_inode_tree_exit(struct hot_info *root)
+{
+     struct hot_inode_item *hi_nodes[8];
+     u64 ino = 0;
+     int i, n;

nitpick, put the declarations on separate lines

quoted

+
+     while (1) {
+             spin_lock(&root->lock);
+             n = radix_tree_gang_lookup(&root->hot_inode_tree,
+                                        (void **)hi_nodes, ino,
+                                        ARRAY_SIZE(hi_nodes));
+             if (!n) {
+                     spin_unlock(&root->lock);
+                     break;
+             }
+
+             ino = hi_nodes[n - 1]->i_ino + 1;
+             for (i = 0; i < n; i++)
+                     hot_inode_item_put(hi_nodes[i]);
+             spin_unlock(&root->lock);
+     }
+}
+
 /*
  * Initialize kmem cache for hot_inode_item and hot_range_item.
  */

@@ -106,3 +197,36 @@ err:
      kmem_cache_destroy(hot_inode_item_cachep);
 }
 EXPORT_SYMBOL_GPL(hot_cache_init);
+
+/*
+ * Initialize the data structures for hot data tracking.
+ */
+int hot_track_init(struct super_block *sb)
+{
+     struct hot_info *root;
+     int ret = -ENOMEM;
+
+     root = kzalloc(sizeof(struct hot_info), GFP_NOFS);
+     if (!root) {
+             printk(KERN_ERR "%s: Failed to malloc memory for "
+                             "hot_info\n", __func__);
+             return ret;

minor: you can drop the variable ret and just reurn ENOMEM here

quoted

+     }
+
+     sb->s_hot_root = root;
+     hot_inode_tree_init(root);
+
+     printk(KERN_INFO "VFS: Turning on hot data tracking\n");
+
+     return 0;
+}
+EXPORT_SYMBOL_GPL(hot_track_init);

david

-- 
Regards,

Zhi Yong Wu