From: Zhi Yong Wu <wu...@linux.vnet.ibm.com>

  Adds two map arrays which contains
a lot of list and is used to efficiently
look up the data temperature of a file or its
ranges.
  In each list of map arrays, the array node
will keep track of temperature info.

Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
---
 fs/hot_tracking.c            |   60 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/hot_tracking.h |   16 +++++++++++
 2 files changed, 76 insertions(+), 0 deletions(-)

diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 1142ef1..7101b73 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -58,6 +58,7 @@ static void hot_range_item_init(struct hot_range_item *hr, 
loff_t start,
        hr->hot_inode = he;
        kref_init(&hr->hot_range.refs);
        spin_lock_init(&hr->hot_range.lock);
+       INIT_LIST_HEAD(&hr->hot_range.n_list);
        hr->hot_range.hot_freq_data.avg_delta_reads = (u64) -1;
        hr->hot_range.hot_freq_data.avg_delta_writes = (u64) -1;
        hr->hot_range.hot_freq_data.flags = FREQ_DATA_TYPE_RANGE;
@@ -89,6 +90,16 @@ static void hot_range_item_free(struct kref *kref)
                struct hot_comm_item, refs);
        struct hot_range_item *hr = container_of(comm_item,
                struct hot_range_item, hot_range);
+       struct hot_info *root = container_of(
+                       hr->hot_inode->hot_inode_tree,
+               struct hot_info, hot_inode_tree);
+
+       spin_lock(&hr->hot_range.lock);
+       if (!list_empty(&hr->hot_range.n_list)) {
+               list_del_init(&hr->hot_range.n_list);
+               root->hot_map_nr--;
+       }
+       spin_unlock(&hr->hot_range.lock);
 
        radix_tree_delete(&hr->hot_inode->hot_range_tree, hr->start);
        kmem_cache_free(hot_range_item_cachep, hr);
@@ -133,6 +144,15 @@ static void hot_inode_item_free(struct kref *kref)
                        struct hot_comm_item, refs);
        struct hot_inode_item *he = container_of(comm_item,
                        struct hot_inode_item, hot_inode);
+       struct hot_info *root = container_of(he->hot_inode_tree,
+               struct hot_info, hot_inode_tree);
+
+       spin_lock(&he->hot_inode.lock);
+       if (!list_empty(&he->hot_inode.n_list)) {
+               list_del_init(&he->hot_inode.n_list);
+               root->hot_map_nr--;
+       }
+       spin_unlock(&he->hot_inode.lock);
 
        hot_range_tree_free(he);
        radix_tree_delete(he->hot_inode_tree, he->i_ino);
@@ -299,6 +319,44 @@ static void hot_freq_data_update(struct hot_freq_data 
*freq_data, bool write)
 }
 
 /*
+ * Initialize inode and range map info.
+ */
+static void hot_map_init(struct hot_info *root)
+{
+       int i;
+       for (i = 0; i < HEAT_MAP_SIZE; i++) {
+               INIT_LIST_HEAD(&root->heat_inode_map[i].node_list);
+               INIT_LIST_HEAD(&root->heat_range_map[i].node_list);
+               root->heat_inode_map[i].temp = i;
+               root->heat_range_map[i].temp = i;
+       }
+}
+
+static void hot_map_list_free(struct list_head *node_list,
+                               struct hot_info *root)
+{
+       struct list_head *pos, *next;
+       struct hot_comm_item *node;
+
+       list_for_each_safe(pos, next, node_list) {
+               node = list_entry(pos, struct hot_comm_item, n_list);
+               list_del_init(&node->n_list);
+               root->hot_map_nr--;
+       }
+
+}
+
+/* Free inode and range map info */
+static void hot_map_exit(struct hot_info *root)
+{
+       int i;
+       for (i = 0; i < HEAT_MAP_SIZE; i++) {
+               hot_map_list_free(&root->heat_inode_map[i].node_list, root);
+               hot_map_list_free(&root->heat_range_map[i].node_list, root);
+       }
+}
+
+/*
  * Initialize kmem cache for hot_inode_item and hot_range_item.
  */
 void __init hot_cache_init(void)
@@ -390,6 +448,7 @@ int hot_track_init(struct super_block *sb)
 
        sb->s_hot_root = root;
        hot_inode_tree_init(root);
+       hot_map_init(root);
 
        printk(KERN_INFO "VFS: Turning on hot data tracking\n");
 
@@ -401,6 +460,7 @@ void hot_track_exit(struct super_block *sb)
 {
        struct hot_info *root = sb->s_hot_root;
 
+       hot_map_exit(root);
        hot_inode_tree_exit(root);
        kfree(root);
 }
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 3797cf0..5227e89 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -20,6 +20,9 @@
 #include <linux/kref.h>
 #include <linux/fs.h>
 
+#define HEAT_MAP_BITS 8
+#define HEAT_MAP_SIZE (1 << HEAT_MAP_BITS)
+
 /*
  * A frequency data struct holds values that are used to
  * determine temperature of files and file ranges. These structs
@@ -36,11 +39,18 @@ struct hot_freq_data {
        u32 last_temp;
 };
 
+/* List heads in hot map array */
+struct hot_map_head {
+       struct list_head node_list;
+       u8 temp;
+};
+
 /* The common info for both following structures */
 struct hot_comm_item {
        struct hot_freq_data hot_freq_data;  /* frequency data */
        spinlock_t lock; /* protects object data */
        struct kref refs;  /* prevents kfree */
+       struct list_head n_list; /* list node index */
 };
 
 /* An item representing an inode and its access frequency */
@@ -66,6 +76,12 @@ struct hot_range_item {
 struct hot_info {
        struct radix_tree_root hot_inode_tree;
        spinlock_t lock; /*protect inode tree */
+
+       /* map of inode temperature */
+       struct hot_map_head heat_inode_map[HEAT_MAP_SIZE];
+       /* map of range temperature */
+       struct hot_map_head heat_range_map[HEAT_MAP_SIZE];
+       unsigned int hot_map_nr;
 };
 
 extern void __init hot_cache_init(void);
-- 
1.7.6.5

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