From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
One root structure hot_info is defined, is hooked
up in super_block, and will be used to hold radix tree
root, hash list root and some other information, etc.
Adds hot_inode_tree struct to keep track of
frequently accessed files, and be keyed by {inode, offset}.
Trees contain hot_inode_items representing those files
and ranges.
Having these trees means that vfs can quickly determine the
temperature of some data by doing some calculations on the
hot_freq_data struct that hangs off of the tree item.
Define two items hot_inode_item and hot_range_item,
one of them represents one tracked file
to keep track of its access frequency and the tree of
ranges in this file, while the latter represents
a file range of one inode.
Each of the two structures contains a hot_freq_data
struct with its frequency of access metrics (number of
{reads, writes}, last {read,write} time, frequency of
{reads,writes}).
Also, each hot_inode_item contains one hot_range_tree
struct which is keyed by {inode, offset, length}
and used to keep track of all the ranges in this file.
Signed-off-by: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
---
fs/Makefile | 2 +-
fs/hot_tracking.c | 138 ++++++++++++++++++++++++++++++++++++++++++
fs/hot_tracking.h | 26 ++++++++
include/linux/hot_tracking.h | 74 ++++++++++++++++++++++
4 files changed, 239 insertions(+), 1 deletions(-)
create mode 100644 fs/hot_tracking.c
create mode 100644 fs/hot_tracking.h
create mode 100644 include/linux/hot_tracking.h
diff --git a/fs/Makefile b/fs/Makefile
index 1d7af79..f966dea 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -11,7 +11,7 @@ obj-y := open.o read_write.o file_table.o super.o \
attr.o bad_inode.o file.o filesystems.o namespace.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o drop_caches.o splice.o sync.o utimes.o \
- stack.o fs_struct.o statfs.o
+ stack.o fs_struct.o statfs.o hot_tracking.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o bio.o block_dev.o direct-io.o mpage.o ioprio.o
diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
new file mode 100644
index 0000000..634ec03
--- /dev/null
+++ b/fs/hot_tracking.c
@@ -0,0 +1,138 @@
+/*
+ * fs/hot_tracking.c
+ *
+ * Copyright (C) 2012 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ */
+
+#include <linux/list.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+#include <linux/hardirq.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include <linux/types.h>
+#include <linux/limits.h>
+#include "hot_tracking.h"
+
+/* kmem_cache pointers for slab caches */
+static struct kmem_cache *hot_inode_item_cachep;
+static struct kmem_cache *hot_range_item_cachep;
+
+/*
+ * Initialize the inode tree. Should be called for each new inode
+ * access or other user of the hot_inode interface.
+ */
+static void hot_inode_tree_init(struct hot_info *root)
+{
+ INIT_RADIX_TREE(&root->hot_inode_tree, GFP_ATOMIC);
+ spin_lock_init(&root->lock);
+}
+
+/*
+ * Initialize the hot range tree. Should be called for each new inode
+ * access or other user of the hot_range interface.
+ */
+void hot_range_tree_init(struct hot_inode_item *he)
+{
+ INIT_RADIX_TREE(&he->hot_range_tree, GFP_ATOMIC);
+ spin_lock_init(&he->lock);
+}
+
+/*
+ * Initialize a new hot_range_item structure. The new structure is
+ * returned with a reference count of one and needs to be
+ * freed using free_range_item()
+ */
+static void hot_range_item_init(struct hot_range_item *hr, u32 start,
+ struct hot_inode_item *he)
+{
+ hr->start = start;
+ hr->len = RANGE_SIZE;
+ hr->hot_inode = he;
+ kref_init(&hr->hot_range.refs);
+ spin_lock_init(&hr->hot_range.lock);
+ 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;
+}
+
+/*
+ * Initialize a new hot_inode_item structure. The new structure is
+ * returned with a reference count of one and needs to be
+ * freed using hot_free_inode_item()
+ */
+static void hot_inode_item_init(struct hot_inode_item *he, u64 ino,
+ struct radix_tree_root *hot_inode_tree)
+{
+ he->i_ino = ino;
+ he->hot_inode_tree = hot_inode_tree;
+ kref_init(&he->hot_inode.refs);
+ spin_lock_init(&he->hot_inode.lock);
+ 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;
+ hot_range_tree_init(he);
+}
+
+/*
+ * Initialize kmem cache for hot_inode_item and hot_range_item.
+ */
+static int __init hot_cache_init(void)
+{
+ hot_inode_item_cachep = kmem_cache_create("hot_inode_item",
+ sizeof(struct hot_inode_item), 0,
+ SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+ NULL);
+ if (!hot_inode_item_cachep)
+ goto inode_err;
+
+ hot_range_item_cachep = kmem_cache_create("hot_range_item",
+ sizeof(struct hot_range_item), 0,
+ SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+ NULL);
+ if (!hot_range_item_cachep)
+ goto range_err;
+
+ return 0;
+
+range_err:
+ kmem_cache_destroy(hot_inode_item_cachep);
+inode_err:
+ return -ENOMEM;
+}
+
+static inline void hot_cache_exit(void)
+{
+ if (hot_range_item_cachep)
+ kmem_cache_destroy(hot_range_item_cachep);
+
+ if (hot_inode_item_cachep)
+ kmem_cache_destroy(hot_inode_item_cachep);
+}
+
+/*
+ * Initialize the data structures for hot data tracking.
+ */
+void hot_track_init(struct super_block *sb)
+{
+ int err;
+
+ err = hot_cache_init();
+ if (err) {
+ printk(KERN_ERR "%s: hot_track_cache_init error: %d\n",
+ __func__, err);
+ return;
+ }
+}
+
+void hot_track_exit(struct super_block *sb)
+{
+ hot_cache_exit();
+}
diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
new file mode 100644
index 0000000..4e8aa77
--- /dev/null
+++ b/fs/hot_tracking.h
@@ -0,0 +1,26 @@
+/*
+ * fs/hot_tracking.h
+ *
+ * Copyright (C) 2012 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ */
+
+#ifndef __HOT_TRACKING__
+#define __HOT_TRACKING__
+
+#include <linux/radix-tree.h>
+#include <linux/workqueue.h>
+#include <linux/hot_tracking.h>
+
+/* values for hot_freq_data flags */
+#define FREQ_DATA_TYPE_INODE (1 << 0)
+#define FREQ_DATA_TYPE_RANGE (1 << 1)
+
+void hot_track_init(struct super_block *sb);
+void hot_track_exit(struct super_block *sb);
+
+#endif /* __HOT_TRACKING__ */
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
new file mode 100644
index 0000000..78adb0d
--- /dev/null
+++ b/include/linux/hot_tracking.h
@@ -0,0 +1,74 @@
+/*
+ * include/linux/hot_tracking.h
+ *
+ * This file has definitions for VFS hot data tracking
+ * structures etc.
+ *
+ * Copyright (C) 2012 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_HOTTRACK_H
+#define _LINUX_HOTTRACK_H
+
+#include <linux/types.h>
+#include <linux/rbtree.h>
+#include <linux/kref.h>
+#include <linux/fs.h>
+
+/*
+ * A frequency data struct holds values that are used to
+ * determine temperature of files and file ranges. These structs
+ * are members of hot_inode_item and hot_range_item
+ */
+struct hot_freq_data {
+ struct timespec last_read_time;
+ struct timespec last_write_time;
+ u32 nr_reads;
+ u32 nr_writes;
+ u64 avg_delta_reads;
+ u64 avg_delta_writes;
+ u32 flags;
+ u32 last_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 */
+};
+
+/* An item representing an inode and its access frequency */
+struct hot_inode_item {
+ struct hot_comm_item hot_inode; /* node in hot_inode_tree */
+ struct radix_tree_root hot_range_tree; /* tree of ranges */
+ spinlock_t lock; /* protect range tree */
+ struct radix_tree_root *hot_inode_tree;
+ u64 i_ino; /* inode number from inode */
+};
+
+/*
+ * An item representing a range inside of
+ * an inode whose frequency is being tracked
+ */
+struct hot_range_item {
+ struct hot_comm_item hot_range;
+ struct hot_inode_item *hot_inode; /* associated hot_inode_item */
+ u32 start; /* item index in hot_range_tree */
+ u32 len; /* length in bytes */
+};
+
+struct hot_info {
+ struct radix_tree_root hot_inode_tree;
+ spinlock_t lock; /*protect inode tree */
+};
+
+extern void hot_track_init(struct super_block *sb);
+extern void hot_track_exit(struct super_block *sb);
+
+#endif /* _LINUX_HOTTRACK_H */
--
1.7.6.5
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