[PATCH v1 hot_track 09/16] vfs: add one work queue

From: zwu . kernel
Date: Fri Nov 16 2012 - 04:52:00 EST


From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>

Add a per-superblock workqueue and a delayed_work
to run periodic work to update map info on each superblock.

Signed-off-by: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
---
fs/hot_tracking.c | 81 ++++++++++++++++++++++++++++++++++++++++++
fs/hot_tracking.h | 3 ++
include/linux/hot_tracking.h | 3 ++
3 files changed, 87 insertions(+), 0 deletions(-)

diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 304028d..873d234 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -15,9 +15,12 @@
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/hardirq.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/types.h>
+#include <linux/list_sort.h>
#include <linux/limits.h>
#include "hot_tracking.h"

@@ -539,6 +542,63 @@ static void hot_map_exit(struct hot_info *root)
}
}

+/* Temperature compare function*/
+static int hot_temp_cmp(void *priv, struct list_head *a,
+ struct list_head *b)
+{
+ struct hot_comm_item *ap =
+ container_of(a, struct hot_comm_item, n_list);
+ struct hot_comm_item *bp =
+ container_of(b, struct hot_comm_item, n_list);
+
+ int diff = ap->hot_freq_data.last_temp
+ - bp->hot_freq_data.last_temp;
+ if (diff > 0)
+ return -1;
+ if (diff < 0)
+ return 1;
+ return 0;
+}
+
+/*
+ * Every sync period we update temperatures for
+ * each hot inode item and hot range item for aging
+ * purposes.
+ */
+static void hot_update_worker(struct work_struct *work)
+{
+ struct hot_info *root = container_of(to_delayed_work(work),
+ struct hot_info, update_work);
+ struct rb_node *node;
+ struct hot_comm_item *ci;
+ struct hot_inode_item *he;
+ int i;
+
+ node = rb_first(&root->hot_inode_tree.map);
+ while (node) {
+ ci = rb_entry(node, struct hot_comm_item, rb_node);
+ he = container_of(ci, struct hot_inode_item, hot_inode);
+ kref_get(&he->hot_inode.refs);
+ hot_map_update(
+ &he->hot_inode.hot_freq_data, root);
+ hot_range_update(he, root);
+ node = rb_next(node);
+ hot_inode_item_put(he);
+ }
+
+ /* Sort temperature map info */
+ for (i = 0; i < HEAT_MAP_SIZE; i++) {
+ list_sort(NULL, &root->heat_inode_map[i].node_list,
+ hot_temp_cmp);
+ list_sort(NULL, &root->heat_range_map[i].node_list,
+ hot_temp_cmp);
+ }
+
+ /* Instert next delayed work */
+ queue_delayed_work(root->update_wq, &root->update_work,
+ msecs_to_jiffies(HEAT_UPDATE_DELAY * MSEC_PER_SEC));
+}
+
/*
* Initialize kmem cache for hot_inode_item and hot_range_item.
*/
@@ -632,11 +692,30 @@ int hot_track_init(struct super_block *sb)
hot_inode_tree_init(root);
hot_map_init(root);

+ root->update_wq = alloc_workqueue(
+ "hot_update_wq", WQ_NON_REENTRANT, 0);
+ if (!root->update_wq) {
+ printk(KERN_ERR "%s: Failed to create "
+ "hot update workqueue\n", __func__);
+ goto failed_wq;
+ }
+
+ /* Initialize hot tracking wq and arm one delayed work */
+ INIT_DELAYED_WORK(&root->update_work, hot_update_worker);
+ queue_delayed_work(root->update_wq, &root->update_work,
+ msecs_to_jiffies(HEAT_UPDATE_DELAY * MSEC_PER_SEC));
+
sb->s_hot_root = root;

printk(KERN_INFO "VFS: Turning on hot data tracking\n");

return 0;
+
+failed_wq:
+ hot_map_exit(root);
+ hot_inode_tree_exit(root);
+ kfree(root);
+ return ret;
}
EXPORT_SYMBOL_GPL(hot_track_init);

@@ -644,6 +723,8 @@ void hot_track_exit(struct super_block *sb)
{
struct hot_info *root = sb->s_hot_root;

+ cancel_delayed_work_sync(&root->update_work);
+ destroy_workqueue(root->update_wq);
hot_map_exit(root);
hot_inode_tree_exit(root);
sb->s_hot_root = NULL;
diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
index 46d068a..96379a6 100644
--- a/fs/hot_tracking.h
+++ b/fs/hot_tracking.h
@@ -30,6 +30,9 @@
*/
#define TIME_TO_KICK 300

+/* set how often to update temperatures (seconds) */
+#define HEAT_UPDATE_DELAY 300
+
/* NRR/NRW heat unit = 2^X accesses */
#define NRR_MULTIPLIER_POWER 20 /* NRR - number of reads since mount */
#define NRR_COEFF_POWER 0
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 34a0530..ef12748 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -88,6 +88,9 @@ struct hot_info {
/* map of range temperature */
struct hot_map_head heat_range_map[HEAT_MAP_SIZE];
unsigned int hot_map_nr;
+
+ struct workqueue_struct *update_wq;
+ struct delayed_work update_work;
};

extern void __init hot_cache_init(void);
--
1.7.6.5

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