[RFC v3 05/13] vfs: add two map arrays

From: zwu . kernel
Date: Wed Oct 10 2012 - 06:12:22 EST


From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>

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 <wuzhy@xxxxxxxxxxxxxxxxxx>
---
fs/hot_tracking.c | 50 ++++++++++++++++++++++++++++++++++++++++++
include/linux/hot_tracking.h | 16 +++++++++++++
2 files changed, 66 insertions(+), 0 deletions(-)

diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 86c87c7..08c42c5 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -60,6 +60,7 @@ static void hot_range_item_init(struct hot_range_item *hr, u32 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;
@@ -77,6 +78,7 @@ static void hot_inode_item_init(struct hot_inode_item *he, u64 ino,
he->hot_inode_tree = hot_inode_tree;
kref_init(&he->hot_inode.refs);
spin_lock_init(&he->hot_inode.lock);
+ INIT_LIST_HEAD(&he->hot_inode.n_list);
he->hot_inode.hot_freq_data.avg_delta_reads = (u64) -1;
he->hot_inode.hot_freq_data.avg_delta_writes = (u64) -1;
he->hot_inode.hot_freq_data.flags = FREQ_DATA_TYPE_INODE;
@@ -90,6 +92,11 @@ static void hot_range_item_free(struct kref *kref)
struct hot_range_item *hr = container_of(comm_item,
struct hot_range_item, hot_range);

+ spin_lock(&hr->hot_range.lock);
+ if (!list_empty(&hr->hot_range.n_list))
+ list_del_init(&hr->hot_range.n_list);
+ 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);
}
@@ -135,6 +142,11 @@ static void hot_inode_item_free(struct kref *kref)
struct hot_inode_item *he = container_of(comm_item,
struct hot_inode_item, hot_inode);

+ spin_lock(&he->hot_inode.lock);
+ if (!list_empty(&he->hot_inode.n_list))
+ list_del_init(&he->hot_inode.n_list);
+ spin_unlock(&he->hot_inode.lock);
+
hot_range_tree_free(he);
radix_tree_delete(he->hot_inode_tree, he->i_ino);
kmem_cache_free(hot_inode_item_cachep, he);
@@ -365,6 +377,42 @@ inline void hot_update_freqs(struct hot_info *root,
}

/*
+ * Initialize inode and range map arrays.
+ */
+static void hot_map_array_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].temperature = i;
+ root->heat_range_map[i].temperature = i;
+ }
+}
+
+static void hot_map_list_free(struct list_head *node_list)
+{
+ 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);
+ }
+
+}
+
+/* Free inode and range map arrays */
+static void hot_map_array_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);
+ hot_map_list_free(&root->heat_range_map[i].node_list);
+ }
+}
+
+/*
* Initialize kmem cache for hot_inode_item and hot_range_item.
*/
static int __init hot_cache_init(void)
@@ -426,6 +474,7 @@ void hot_track_init(struct super_block *sb)
global_hot_tracking_info = root;
sb->hot_flags |= MS_HOT_TRACKING;
hot_inode_tree_init(root);
+ hot_map_array_init(root);

printk(KERN_INFO "vfs: turning on hot data tracking\n");

@@ -439,6 +488,7 @@ void hot_track_exit(struct super_block *sb)
{
struct hot_info *root = global_hot_tracking_info;

+ hot_map_array_exit(root);
hot_inode_tree_exit(root);
sb->hot_flags &= ~MS_HOT_TRACKING;
hot_cache_exit();
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 1e0aed5..7114179 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -22,6 +22,9 @@

#define MS_HOT_TRACKING (1<<0)

+#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
@@ -38,11 +41,18 @@ struct hot_freq_data {
u32 last_temperature;
};

+/* List heads in hot map array */
+struct hot_map_head {
+ struct list_head node_list;
+ u32 temperature;
+};
+
/* 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 */
@@ -68,6 +78,12 @@ 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];
};

extern struct hot_info *global_hot_tracking_info;
--
1.7.6.5

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