[RFC v4 11/15] vfs,hot_track: add debugfs support

From: zwu . kernel
Date: Thu Oct 25 2012 - 11:12:08 EST

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From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>

Add a /sys/kernel/debug/hot_track/<device_name>/ directory for each
volume that contains two files. The first, `inode_stats', contains the
heat information for inodes that have been brought into the hot data map
structures. The second, `range_stats', contains similar information for
subfile ranges.

Signed-off-by: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
---
fs/debugfs/inode.c | 26 +++
fs/hot_tracking.c | 458 ++++++++++++++++++++++++++++++++++++++++++
fs/hot_tracking.h | 5 +
include/linux/debugfs.h | 9 +
include/linux/hot_tracking.h | 1 +
5 files changed, 499 insertions(+), 0 deletions(-)

diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index b607d92..c6291bc 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -354,6 +354,32 @@ exit:
return dentry;
}

+struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len)
+{
+ struct dentry *dentry = NULL;
+ int error = 0;
+
+ error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
+ &debugfs_mount_count);
+ if (error)
+ return NULL;
+
+ if (!parent)
+ parent = debugfs_mount->mnt_root;
+
+ mutex_lock(&parent->d_inode->i_mutex);
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (!IS_ERR(dentry)) {
+ mutex_unlock(&parent->d_inode->i_mutex);
+ return dentry;
+ }
+ mutex_unlock(&parent->d_inode->i_mutex);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(debugfs_get_dentry);
+
/**
* debugfs_create_file - create a file in the debugfs filesystem
* @name: a pointer to a string containing the name of the file to create.
diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
index 7d2c53d..18a64ee 100644
--- a/fs/hot_tracking.c
+++ b/fs/hot_tracking.c
@@ -21,6 +21,7 @@
#include <linux/blkdev.h>
#include <linux/types.h>
#include <linux/list_sort.h>
+#include <linux/debugfs.h>
#include <linux/limits.h>
#include "hot_tracking.h"

@@ -654,6 +655,451 @@ static void hot_update_worker(struct work_struct *work)
}

/*
+ * take the inode, find ranges associated with inode
+ * and print each range data struct
+ */
+static struct hot_range_item
+*hot_range_tree_walk(struct hot_inode_item *he,
+ loff_t *pos, u32 start, bool flag)
+{
+ struct hot_range_item *hr_nodes[8];
+ loff_t l = *pos;
+ int i, n;
+
+ /* Walk the hot_range_tree for inode */
+ while (1) {
+ spin_lock(&he->lock);
+ n = radix_tree_gang_lookup(&he->hot_range_tree,
+ (void **)hr_nodes, start,
+ ARRAY_SIZE(hr_nodes));
+ if (!n) {
+ spin_unlock(&he->lock);
+ break;
+ }
+ spin_unlock(&he->lock);
+
+ start = hr_nodes[n - 1]->start + 1;
+ for (i = 0; i < n; i++) {
+ if ((!flag && !l--) || (flag)) {
+ if (flag)
+ (*pos)++;
+ kref_get(&hr_nodes[i]->hot_range.refs);
+ return hr_nodes[i];
+ }
+ }
+ }
+
+ return NULL;
+}
+
+static void
+*hot_inode_tree_walk(u64 ino, loff_t *pos, bool type, bool flag)
+{
+ struct hot_inode_item *hi_nodes[8];
+ struct hot_range_item *hr;
+ loff_t l = *pos;
+ int i, n;
+
+ while (1) {
+ spin_lock(&hot_root->lock);
+ n = radix_tree_gang_lookup(&hot_root->hot_inode_tree,
+ (void **)hi_nodes, ino,
+ ARRAY_SIZE(hi_nodes));
+ if (!n) {
+ spin_unlock(&hot_root->lock);
+ break;
+ }
+ spin_unlock(&hot_root->lock);
+
+ ino = hi_nodes[n - 1]->i_ino + 1;
+ for (i = 0; i < n; i++) {
+ if (!type) {
+ hr = hot_range_tree_walk(hi_nodes[i],
+ pos, 0, flag);
+ if (hr)
+ return hr;
+ } else {
+ if ((!flag && !l--) || (flag)) {
+ if (flag)
+ (*pos)++;
+ kref_get(&hi_nodes[i]->hot_inode.refs);
+ return hi_nodes[i];
+ }
+ }
+ }
+ }
+
+ return NULL;
+}
+
+static void *hot_range_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ return hot_inode_tree_walk(0, pos, false, false);
+}
+
+static void *hot_range_seq_next(struct seq_file *seq,
+ void *v, loff_t *pos)
+{
+ struct hot_range_item *hr_next, *hr = v;
+ u32 start = hr->start + 1;
+
+ /* Walk the hot_range_tree for inode */
+ hr_next = hot_range_tree_walk(hr->hot_inode, pos, start, true);
+ if (hr_next)
+ return hr_next;
+
+ return hot_inode_tree_walk(hr->hot_inode->i_ino + 1,
+ pos, false, true);
+}
+
+static void hot_range_seq_stop(struct seq_file *seq, void *v)
+{
+ struct hot_range_item *hr = v;
+
+ if (hr)
+ hot_range_item_put(hr);
+}
+
+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 " \
+ "%llu (range len %u) reads %u, writes %u, "
+ "avg read time %llu, avg write time %llu, temp %u\n",
+ 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 void *hot_inode_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ return hot_inode_tree_walk(0, pos, true, false);
+}
+
+static void *hot_inode_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct hot_inode_item *he = v;
+ u64 ino = he->i_ino + 1;
+
+ hot_inode_item_put(he);
+
+ return hot_inode_tree_walk(ino, pos, true, true);
+}
+
+static void hot_inode_seq_stop(struct seq_file *seq, void *v)
+{
+ struct hot_inode_item *he = v;
+
+ if (he)
+ hot_inode_item_put(he);
+}
+
+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",
+ 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_start(struct seq_file *seq, loff_t *pos)
+{
+ struct hot_range_item *hr;
+ struct hot_comm_item *comm_item;
+ struct list_head *n_list;
+ int i;
+
+ for (i = HEAT_MAP_SIZE - 1; i >= 0; i--) {
+ n_list = seq_list_start(
+ &hot_root->heat_range_map[i].node_list, *pos);
+ if (n_list) {
+ comm_item = container_of(n_list,
+ struct hot_comm_item, n_list);
+ hr = container_of(comm_item,
+ struct hot_range_item, hot_range);
+ kref_get(&hr->hot_range.refs);
+ return hr;
+ }
+ }
+
+ return NULL;
+}
+
+static void *hot_spot_range_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ 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);
+
+ n_list = seq_list_next(&hr->hot_range.n_list,
+ &hot_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(&hot_root->heat_range_map[i].node_list,
+ &hot_root->heat_range_map[i].node_list, pos);
+ goto next;
+ }
+
+ return NULL;
+}
+
+static void *hot_spot_inode_seq_start(struct seq_file *seq, loff_t *pos)
+{
+ struct hot_inode_item *he;
+ struct hot_comm_item *comm_item;
+ struct list_head *n_list;
+ int i;
+
+ for (i = HEAT_MAP_SIZE - 1; i >= 0; i--) {
+ n_list = seq_list_start(
+ &hot_root->heat_inode_map[i].node_list, *pos);
+ if (n_list) {
+ comm_item = container_of(n_list,
+ struct hot_comm_item, n_list);
+ he = container_of(comm_item,
+ struct hot_inode_item, hot_inode);
+ kref_get(&he->hot_inode.refs);
+ return he;
+ }
+ }
+
+ return NULL;
+}
+
+static void *hot_spot_inode_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct hot_inode_item *he_next, *he = v;
+ struct hot_comm_item *comm_item;
+ struct list_head *n_list;
+ int i =
+ he->hot_inode.hot_freq_data.last_temp >> (32 - HEAT_MAP_BITS);
+
+ n_list = seq_list_next(&he->hot_inode.n_list,
+ &hot_root->heat_inode_map[i].node_list, pos);
+ hot_inode_item_put(he);
+next:
+ if (n_list) {
+ comm_item = container_of(n_list,
+ struct hot_comm_item, n_list);
+ he_next = container_of(comm_item,
+ struct hot_inode_item, hot_inode);
+ kref_get(&he_next->hot_inode.refs);
+ return he_next;
+ } else if (--i >= 0) {
+ n_list = seq_list_next(&hot_root->heat_inode_map[i].node_list,
+ &hot_root->heat_inode_map[i].node_list, pos);
+ goto next;
+ }
+
+ return NULL;
+}
+
+static const struct seq_operations hot_range_seq_ops = {
+ .start = hot_range_seq_start,
+ .next = hot_range_seq_next,
+ .stop = hot_range_seq_stop,
+ .show = hot_range_seq_show
+};
+
+static const struct seq_operations hot_inode_seq_ops = {
+ .start = hot_inode_seq_start,
+ .next = hot_inode_seq_next,
+ .stop = hot_inode_seq_stop,
+ .show = hot_inode_seq_show
+};
+
+static const struct seq_operations hot_spot_range_seq_ops = {
+ .start = hot_spot_range_seq_start,
+ .next = hot_spot_range_seq_next,
+ .stop = hot_range_seq_stop,
+ .show = hot_range_seq_show
+};
+
+static const struct seq_operations hot_spot_inode_seq_ops = {
+ .start = hot_spot_inode_seq_start,
+ .next = hot_spot_inode_seq_next,
+ .stop = hot_inode_seq_stop,
+ .show = hot_inode_seq_show
+};
+
+static int hot_range_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &hot_range_seq_ops);
+}
+
+static int hot_inode_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &hot_inode_seq_ops);
+}
+
+static int hot_spot_range_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &hot_spot_range_seq_ops);
+}
+
+static int hot_spot_inode_seq_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &hot_spot_inode_seq_ops);
+}
+
+/* fops to override for printing range data */
+static const struct file_operations hot_debugfs_range_fops = {
+ .open = hot_range_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/* fops to override for printing inode data */
+static const struct file_operations hot_debugfs_inode_fops = {
+ .open = hot_inode_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/* fops to override for printing temperature data */
+static const struct file_operations hot_debugfs_spot_range_fops = {
+ .open = hot_spot_range_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static const struct file_operations hot_debugfs_spot_inode_fops = {
+ .open = hot_spot_inode_seq_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static const struct hot_debugfs hot_debugfs[] = {
+ {
+ .name = "rt_stats_range",
+ .fops = &hot_debugfs_range_fops,
+ },
+ {
+ .name = "rt_stats_inode",
+ .fops = &hot_debugfs_inode_fops,
+ },
+ {
+ .name = "hot_spots_range",
+ .fops = &hot_debugfs_spot_range_fops,
+ },
+ {
+ .name = "hot_spots_inode",
+ .fops = &hot_debugfs_spot_inode_fops,
+ },
+};
+
+/* initialize debugfs */
+static int hot_debugfs_init(struct super_block *sb)
+{
+ static const char hot_name[] = "hot_track";
+ struct dentry *vol_dentry, *dentry;
+ int i, ret = 0;
+
+ /* Determine if hot debufs root has existed */
+ sb->s_hot_root->debugfs_root =
+ debugfs_get_dentry(hot_name, NULL, strlen(hot_name));
+ if (IS_ERR_OR_NULL(sb->s_hot_root->debugfs_root)
+ || !sb->s_hot_root->debugfs_root->d_inode) {
+ sb->s_hot_root->debugfs_root =
+ debugfs_create_dir(hot_name, NULL);
+ if (IS_ERR(sb->s_hot_root->debugfs_root)) {
+ ret = PTR_ERR(sb->s_hot_root->debugfs_root);
+ return ret;
+ }
+ }
+
+ if (!S_ISDIR(sb->s_hot_root->debugfs_root->d_inode->i_mode))
+ return -ENOTDIR;
+
+ /* create debugfs folder for this volume by mounted dev name */
+ vol_dentry = debugfs_create_dir(sb->s_id, sb->s_hot_root->debugfs_root);
+ if (IS_ERR(vol_dentry)) {
+ ret = PTR_ERR(vol_dentry);
+ goto err;
+ }
+
+ /* create debugfs hot data files */
+ for (i = 0; i < ARRAY_SIZE(hot_debugfs); i++) {
+ dentry = debugfs_create_file(hot_debugfs[i].name,
+ S_IFREG | S_IRUSR | S_IWUSR,
+ vol_dentry,
+ NULL,
+ hot_debugfs[i].fops);
+ if (IS_ERR(dentry)) {
+ ret = PTR_ERR(dentry);
+ goto err;
+ }
+ }
+
+ return 0;
+
+err:
+ debugfs_remove_recursive(vol_dentry);
+
+ if (list_empty(&sb->s_hot_root->debugfs_root->d_subdirs))
+ debugfs_remove(sb->s_hot_root->debugfs_root);
+
+ return ret;
+}
+
+/* remove dentries for debugsfs */
+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);
+
+ if (list_empty(&sb->s_hot_root->debugfs_root->d_subdirs))
+ debugfs_remove(sb->s_hot_root->debugfs_root);
+}
+
+/*
* Initialize kmem cache for hot_inode_item and hot_range_item.
*/
void __init hot_cache_init(void)
@@ -818,10 +1264,21 @@ int hot_track_init(struct super_block *sb)
root->hot_shrink.seeks = DEFAULT_SEEKS;
register_shrinker(&root->hot_shrink);

+ ret = hot_debugfs_init(sb);
+ if (ret) {
+ printk(KERN_ERR "%s: hot_debugfs_init error: %d\n",
+ __func__, ret);
+ goto failed_debugfs;
+ }
+
printk(KERN_INFO "VFS: Turning on hot data tracking\n");

return 0;

+failed_debugfs:
+ unregister_shrinker(&root->hot_shrink);
+ cancel_delayed_work_sync(&root->update_work);
+ destroy_workqueue(root->update_wq);
failed_wq:
hot_map_array_exit(root);
hot_inode_tree_exit(root);
@@ -839,6 +1296,7 @@ void hot_track_exit(struct super_block *sb)
destroy_workqueue(root->update_wq);
hot_map_array_exit(root);
hot_inode_tree_exit(root);
+ hot_debugfs_exit(sb);
kfree(root);
}
EXPORT_SYMBOL_GPL(hot_track_exit);
diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
index b9d9717..6eb024f 100644
--- a/fs/hot_tracking.h
+++ b/fs/hot_tracking.h
@@ -87,6 +87,11 @@
#define AVW_DIVIDER_POWER 40
#define AVW_COEFF_POWER 0

+struct hot_debugfs {
+ const char *name;
+ const struct file_operations *fops;
+};
+
struct hot_inode_item
*hot_inode_item_find(struct hot_info *root, u64 ino);
void hot_inode_item_put(struct hot_inode_item *he);
diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index 66c434f..8913a4d 100644
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -46,6 +46,9 @@ extern struct dentry *arch_debugfs_dir;
extern const struct file_operations debugfs_file_operations;
extern const struct inode_operations debugfs_link_operations;

+struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len);
+
struct dentry *debugfs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);
@@ -103,6 +106,12 @@ bool debugfs_initialized(void);

#include <linux/err.h>

+static inline struct dentry *debugfs_get_dentry(const char *name,
+ struct dentry *parent, int len)
+{
+ return ERR_PTR(-ENODEV);
+}
+
/*
* We do not return NULL from these functions if CONFIG_DEBUG_FS is not enabled
* so users have a chance to detect if there was a real error or not. We don't
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index c81c331..7107cfa 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -97,6 +97,7 @@ struct hot_info {
struct workqueue_struct *update_wq;
struct delayed_work update_work;
struct shrinker hot_shrink;
+ struct dentry *debugfs_root;
};

/*
--
1.7.6.5

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