On Mon, Oct 29, 2012 at 12:30:56PM +0800, zwu.kernel@gmail.com wrote:

+static int hot_range_seq_show(struct seq_file *seq, void *v)
+{
+	struct hot_range_item *hr = v;
+	struct hot_inode_item *he = hr->hot_inode;
+	struct hot_freq_data *freq_data = &hr->hot_range.hot_freq_data;
+
+	/* Always lock hot_inode_item first */
+	spin_lock(&he->hot_inode.lock);
+	spin_lock(&hr->hot_range.lock);
+	seq_printf(seq, "inode #%llu, range start " \

the # seems unnecessary to me

+			"%llu (range len %u) reads %u, writes %u, "
+			"avg read time %llu, avg write time %llu, temp %u\n",

compiler will complain if it sees a %llu format and not the expected
type of 'unsigned long long'

+			he->i_ino,

			(unsigned long long)he->i_ino,

+			(u64)hr->start * RANGE_SIZE,
+			hr->len,
+			freq_data->nr_reads,
+			freq_data->nr_writes,
+			freq_data->avg_delta_reads / NSEC_PER_MSEC,
+			freq_data->avg_delta_writes / NSEC_PER_MSEC,
+			freq_data->last_temp >> (32 - HEAT_MAP_BITS));
+	spin_unlock(&hr->hot_range.lock);
+	spin_unlock(&he->hot_inode.lock);
+
+	return 0;
+}
+
+static int hot_inode_seq_show(struct seq_file *seq, void *v)
+{
+	struct hot_inode_item *he = v;
+	struct hot_freq_data *freq_data = &he->hot_inode.hot_freq_data;
+
+	spin_lock(&he->hot_inode.lock);
+	seq_printf(seq, "inode #%llu, reads %u, writes %u, " \
+		"avg read time %llu, avg write time %llu, temp %u\n",

(same here)

+		he->i_ino,
+		freq_data->nr_reads,
+		freq_data->nr_writes,
+		freq_data->avg_delta_reads / NSEC_PER_MSEC,
+		freq_data->avg_delta_writes / NSEC_PER_MSEC,
+		freq_data->last_temp >> (32 - HEAT_MAP_BITS));
+	spin_unlock(&he->hot_inode.lock);
+
+	return 0;
+}

+static void *hot_spot_range_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct hot_info *root = seq->private;
+	struct hot_range_item *hr_next, *hr = v;
+	struct hot_comm_item *comm_item;
+	struct list_head *n_list;
+	int i =
+	 hr->hot_range.hot_freq_data.last_temp >> (32 - HEAT_MAP_BITS);

now I have noticed that I've seen the ... (32 - HEAT_MAP_BITS)
expression so many times that it tend to think it deserves a helper
function

+
+	n_list = seq_list_next(&hr->hot_range.n_list,
+		&root->heat_range_map[i].node_list, pos);
+	hot_range_item_put(hr);
+next:
+	if (n_list) {
+		comm_item = container_of(n_list,
+			struct hot_comm_item, n_list);
+		hr_next = container_of(comm_item,
+			struct hot_range_item, hot_range);
+		kref_get(&hr_next->hot_range.refs);
+		return hr_next;
+	} else if (--i >= 0) {
+		n_list = seq_list_next(&root->heat_range_map[i].node_list,
+				&root->heat_range_map[i].node_list, pos);
+		goto next;
+	}
+
+	return NULL;
+}
+
+static void hot_debugfs_exit(struct super_block *sb)
+{
+	struct dentry *vol_dentry;
+
+	vol_dentry = debugfs_get_dentry(sb->s_id,
+				sb->s_hot_root->debugfs_root, strlen(sb->s_id));
+	/* remove all debugfs entries recursively from the volume root */
+	if (vol_dentry)
+		debugfs_remove_recursive(vol_dentry);
+	else
+		BUG_ON(1);

		BUG()

+
+	if (list_empty(&sb->s_hot_root->debugfs_root->d_subdirs))
+		debugfs_remove(sb->s_hot_root->debugfs_root);
+}
+
+/*

david