From: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
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.
Signed-off-by: Chandra Seetharaman <sekha...@us.ibm.com>
Signed-off-by: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
---
fs/Makefile | 2 +-
fs/dcache.c | 2 +
fs/hot_tracking.c | 209 +++++++++++++++++++++++++++++++++++++++++++
fs/hot_tracking.h | 17 ++++
include/linux/fs.h | 4 +
include/linux/hot_tracking.h | 103 +++++++++++++++++++++
6 files changed, 336 insertions(+), 1 deletion(-)
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 199c880..d0fc704 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -13,7 +13,7 @@ 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 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/dcache.c b/fs/dcache.c
index f09b908..9d7c2af 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -37,6 +37,7 @@
#include <linux/rculist_bl.h>
#include <linux/prefetch.h>
#include <linux/ratelimit.h>
+#include <linux/hot_tracking.h>
#include "internal.h"
#include "mount.h"
@@ -3094,4 +3095,5 @@ void __init vfs_caches_init(unsigned long mempages)
mnt_init();
bdev_cache_init();
chrdev_init();
+ hot_cache_init();
}
diff --git a/fs/hot_tracking.c b/fs/hot_tracking.c
new file mode 100644
index 0000000..6bf4229
--- /dev/null
+++ b/fs/hot_tracking.c
@@ -0,0 +1,209 @@
+/*
+ * fs/hot_tracking.c
+ *
+ * Copyright (C) 2013 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wu...@linux.vnet.ibm.com>
+ *
+ * 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/fs.h>
+#include <linux/types.h>
+#include <linux/list_sort.h>
+#include <linux/limits.h>
+#include "hot_tracking.h"
+
+/* 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;
+
+static void hot_inode_item_free(struct kref *kref);
+
+static void hot_comm_item_free_cb(struct rcu_head *head)
+{
+ struct hot_comm_item *ci = container_of(head,
+ struct hot_comm_item, c_rcu);
+
+ if (ci->hot_freq_data.flags == TYPE_RANGE) {
+ struct hot_range_item *hr = container_of(ci,
+ struct hot_range_item, hot_range);
+ kmem_cache_free(hot_range_item_cachep, hr);
+ } else {
+ struct hot_inode_item *he = container_of(ci,
+ struct hot_inode_item, hot_inode);
+ kmem_cache_free(hot_inode_item_cachep, he);
+ }
+}
+
+static void hot_range_item_free(struct kref *kref)
+{
+ struct hot_comm_item *ci = container_of(kref,
+ struct hot_comm_item, refs);
+ struct hot_range_item *hr = container_of(ci,
+ struct hot_range_item, hot_range);
+
+ hr->hot_inode = NULL;
+
+ call_rcu(&hr->hot_range.c_rcu, hot_comm_item_free_cb);
+}
+
+/*
+ * Drops the reference out on hot_comm_item by one
+ * and free the structure if the reference count hits zero
+ */
+void hot_comm_item_put(struct hot_comm_item *ci)
+{
+ kref_put(&ci->refs, (ci->hot_freq_data.flags == TYPE_RANGE) ?
+ hot_range_item_free : hot_inode_item_free);
+}
+EXPORT_SYMBOL_GPL(hot_comm_item_put);
+
+static void hot_comm_item_unlink(struct hot_info *root,
+ struct hot_comm_item *ci)
+{
+ if (!test_and_set_bit(HOT_DELETING, &ci->delete_flag)) {
+ hot_comm_item_put(ci);
+ }
+}
+
+/*
+ * Frees the entire hot_range_tree.
+ */
+static void hot_range_tree_free(struct hot_inode_item *he)
+{
+ struct hot_info *root = he->hot_root;
+ struct rb_node *node;
+ struct hot_comm_item *ci;
+
+ /* Free hot inode and range trees on fs root */
+ rcu_read_lock();
+ node = rb_first(&he->hot_range_tree);
+ while (node) {
+ ci = rb_entry(node, struct hot_comm_item, rb_node);
+ node = rb_next(node);
+ hot_comm_item_unlink(root, ci);
+ }
+ rcu_read_unlock();
+
+}
+
+static void hot_inode_item_free(struct kref *kref)
+{
+ struct hot_comm_item *ci = container_of(kref,
+ struct hot_comm_item, refs);
+ struct hot_inode_item *he = container_of(ci,
+ struct hot_inode_item, hot_inode);
+
+ hot_range_tree_free(he);
+ he->hot_root = NULL;
+
+ call_rcu(&he->hot_inode.c_rcu, hot_comm_item_free_cb);
+}
+
+/*
+ * Initialize kmem cache for hot_inode_item and hot_range_item.
+ */
+void __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)
+ return;
+
+ 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)
+ kmem_cache_destroy(hot_inode_item_cachep);
+}
+EXPORT_SYMBOL_GPL(hot_cache_init);
+
+static struct hot_info *hot_tree_init(struct super_block *sb)
+{
+ struct hot_info *root;
+ int i, j;
+
+ root = kzalloc(sizeof(struct hot_info), GFP_NOFS);
+ if (!root) {
+ printk(KERN_ERR "%s: Failed to malloc memory for "
+ "hot_info\n", __func__);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ root->hot_inode_tree = RB_ROOT;
+ spin_lock_init(&root->t_lock);
+ spin_lock_init(&root->m_lock);
+
+ for (i = 0; i < MAP_SIZE; i++) {
+ for (j = 0; j < MAX_TYPES; j++)
+ INIT_LIST_HEAD(&root->hot_map[j][i]);
+ }
+
+ return root;
+}
+
+/*
+ * Frees the entire hot tree.
+ */
+static void hot_tree_exit(struct hot_info *root)
+{
+ struct rb_node *node;
+ struct hot_comm_item *ci;
+
+ rcu_read_lock();
+ node = rb_first(&root->hot_inode_tree);
+ while (node) {
+ struct hot_inode_item *he;
+ ci = rb_entry(node, struct hot_comm_item, rb_node);
+ he = container_of(ci, struct hot_inode_item, hot_inode);
+ node = rb_next(node);
+ hot_comm_item_unlink(root, &he->hot_inode);
+ }
+ rcu_read_unlock();
+}
+
+/*
+ * Initialize the data structures for hot tracking.
+ * This function will be called by *_fill_super()
+ * when filesystem is mounted.
+ */
+int hot_track_init(struct super_block *sb)
+{
+ struct hot_info *root;
+
+ root = hot_tree_init(sb);
+ if (IS_ERR(root))
+ return PTR_ERR(root);
+
+ sb->s_hot_root = root;
+
+ printk(KERN_INFO "VFS: Turning on hot data tracking\n");
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(hot_track_init);
+
+/*
+ * This function will be called by *_put_super()
+ * when filesystem is umounted, or also by *_fill_super()
+ * in some exceptional cases.
+ */
+void hot_track_exit(struct super_block *sb)
+{
+ struct hot_info *root = sb->s_hot_root;
+
+ hot_tree_exit(root);
+ sb->s_hot_root = NULL;
+ kfree(root);
+}
+EXPORT_SYMBOL_GPL(hot_track_exit);
diff --git a/fs/hot_tracking.h b/fs/hot_tracking.h
new file mode 100644
index 0000000..a2ee95f
--- /dev/null
+++ b/fs/hot_tracking.h
@@ -0,0 +1,17 @@
+/*
+ * fs/hot_tracking.h
+ *
+ * Copyright (C) 2013 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wu...@linux.vnet.ibm.com>
+ *
+ * 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/hot_tracking.h>
+
+#endif /* __HOT_TRACKING__ */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 43db02e..ee2c54f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -27,6 +27,7 @@
#include <linux/lockdep.h>
#include <linux/percpu-rwsem.h>
#include <linux/blk_types.h>
+#include <linux/hot_tracking.h>
#include <asm/byteorder.h>
#include <uapi/linux/fs.h>
@@ -1322,6 +1323,9 @@ struct super_block {
/* Being remounted read-only */
int s_readonly_remount;
+
+ /* Hot data tracking*/
+ struct hot_info *s_hot_root;
};
/* superblock cache pruning functions */
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
new file mode 100644
index 0000000..fa99439
--- /dev/null
+++ b/include/linux/hot_tracking.h
@@ -0,0 +1,103 @@
+/*
+ * include/linux/hot_tracking.h
+ *
+ * This file has definitions for VFS hot data tracking
+ * structures etc.
+ *
+ * Copyright (C) 2013 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wu...@linux.vnet.ibm.com>
+ *
+ * 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>
+
+#ifdef __KERNEL__
+
+#include <linux/rbtree.h>
+#include <linux/kref.h>
+#include <linux/fs.h>
+
+#define MAP_BITS 8
+#define MAP_SIZE (1 << MAP_BITS)
+
+/* values for hot_freq_data flags */
+enum {
+ TYPE_INODE = 0,
+ TYPE_RANGE,
+ MAX_TYPES
+};
+
+enum {
+ HOT_DELETING,
+};
+
+/*
+ * 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_temp;
+};
+
+/* The common info for both following structures */
+struct hot_comm_item {
+ struct hot_freq_data hot_freq_data; /* frequency data */
+ struct kref refs;
+ struct rb_node rb_node; /* rbtree index */
+ unsigned long delete_flag;
+ struct rcu_head c_rcu;
+};
+
+/* 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 rb_root hot_range_tree; /* tree of ranges */
+ spinlock_t i_lock; /* protect above tree */
+};
+
+/*
+ * 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 */
+};
+
+struct hot_info {
+ struct rb_root hot_inode_tree;
+ spinlock_t t_lock; /* protect above tree */
+ struct list_head hot_map[MAX_TYPES][MAP_SIZE]; /* map of inode temp */
+ spinlock_t m_lock;
+};
+
+extern void __init hot_cache_init(void);
+extern int hot_track_init(struct super_block *sb);
+extern void hot_track_exit(struct super_block *sb);
+extern void hot_comm_item_put(struct hot_comm_item *ci);
+
+static inline u64 hot_shift(u64 counter, u32 bits, bool dir)
+{
+ if (dir)
+ return counter << bits;
+ else
+ return counter >> bits;
+}
+
+#endif /* __KERNEL__ */
+
+#endif /* _LINUX_HOTTRACK_H */
--
1.7.11.7
--
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