[PATCH v6 06/11] VFS hot tracking: Add a /proc interface to make the interval tunable

Zhi Yong Wu
2013-11-06T13:48:34Z

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

Add a /proc interface hot-update-interval under the dir
/proc/sys/fs/ in order to turn HOT_UPDATE_INTERVAL into
a tunable parameter.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
fs/hot_tracking.c | 6 ++++--
fs/hot_tracking.h | 2 --
include/linux/hot_tracking.h | 3 +++
kernel/sysctl.c | 7 +++++++
4 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index ac0cdda..7a9bd4f 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -15,6 +15,8 @@
#include <linux/sched.h>
#include "hot_tracking.h"

+int sysctl_hot_update_interval __read_mostly = 150;
+
/* kmem_cache pointers for slab caches */
static struct kmem_cache *hot_inode_item_cachep __read_mostly;
static struct kmem_cache *hot_range_item_cachep __read_mostly;
@@ -556,7 +558,7 @@ static void hot_update_worker(struct work_struct *work)

/* Instert next delayed work */
queue_delayed_work(root->update_wq, &root->update_work,
- msecs_to_jiffies(HOT_UPDATE_INTERVAL * MSEC_PER_SEC));
+ msecs_to_jiffies(sysctl_hot_update_interval * MSEC_PER_SEC));
}

/*
@@ -696,7 +698,7 @@ static struct hot_info *hot_tree_init(struct super_block *sb)
/* 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(HOT_UPDATE_INTERVAL * MSEC_PER_SEC));
+ msecs_to_jiffies(sysctl_hot_update_interval * MSEC_PER_SEC));

/* Register a shrinker callback */
root->hot_shrink.count_objects = hot_track_shrink_count;
diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
index 4a89fdb..6a6971e 100644
--- a/fs/hot_tracking.h
+++ b/fs/hot_tracking.h
@@ -15,8 +15,6 @@
#include <linux/workqueue.h>
#include <linux/hot_tracking.h>

-#define HOT_UPDATE_INTERVAL 150
-
/* size of sub-file ranges */
#define RANGE_BITS 20
#define FREQ_POWER 4
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 0ee9ca2..43df1b9 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -85,6 +85,9 @@ struct hot_info {
struct shrinker hot_shrink;
};

+/* set how often to update temperatures (seconds) */
+extern int sysctl_hot_update_interval;
+
/*
* Hot data tracking ioctls:
*
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index b2f06f3..e0b062a 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -1631,6 +1631,13 @@ static struct ctl_table fs_table[] = {
.proc_handler = &pipe_proc_fn,
.extra1 = &pipe_min_size,
},
+ {
+ .procname = "hot-update-interval",
+ .data = &sysctl_hot_update_interval,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
{ }
};

--
1.7.11.7