[PATCH v6 05/11] VFS hot tracking: Add an ioctl to get hot tracking information

Zhi Yong Wu
2013-11-06T13:48:27Z

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

FS_IOC_GET_HEAT_INFO: return a struct containing the various
metrics collected in hot_freq_data structs, and also return a
calculated data temperature based on those metrics.

Optionally, retrieve the temperature from the hot data hash list
instead of recalculating it.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
fs/compat_ioctl.c | 5 +++
fs/ioctl.c | 71 +++++++++++++++++++++++++++++++++++++++
include/linux/hot_tracking.h | 10 +++++-
include/uapi/linux/hot_tracking.h | 33 ++++++++++++++++++
4 files changed, 118 insertions(+), 1 deletion(-)
create mode 100644 include/uapi/linux/hot_tracking.h

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index 5d19acf..9026b8a 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -57,6 +57,7 @@
#include <linux/i2c-dev.h>
#include <linux/atalk.h>
#include <linux/gfp.h>
+#include <linux/hot_tracking.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci.h>
@@ -1399,6 +1400,9 @@ COMPATIBLE_IOCTL(TIOCSTART)
COMPATIBLE_IOCTL(TIOCSTOP)
#endif

+/*Hot data tracking*/
+COMPATIBLE_IOCTL(FS_IOC_GET_HEAT_INFO)
+
/* fat 'r' ioctls. These are handled by fat with ->compat_ioctl,
but we don't want warnings on other file systems. So declare
them as compatible here. */
@@ -1578,6 +1582,7 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
case FIBMAP:
case FIGETBSZ:
case FIONREAD:
+ case FS_IOC_GET_HEAT_INFO:
if (S_ISREG(file_inode(f.file)->i_mode))
break;
/*FALL THROUGH*/
diff --git a/fs/ioctl.c b/fs/ioctl.c
index fd507fb..b3693ea 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -15,6 +15,7 @@
#include <linux/writeback.h>
#include <linux/buffer_head.h>
#include <linux/falloc.h>
+#include "hot_tracking.h"

#include <asm/ioctls.h>

@@ -537,6 +538,73 @@ static int ioctl_fsthaw(struct file *filp)
}

/*
+ * Retrieve information about access frequency for the given inode.
+ *
+ * The temperature that is returned can be "live" -- that is, recalculated when
+ * the ioctl is called -- or it can be returned from the map list, reflecting
+ * the (possibly old) value that the system will use when considering files
+ * for migration. This behavior is determined by hot_heat_info->live.
+ */
+static int ioctl_heat_info(struct file *file, void __user *argp)
+{
+ struct inode *inode = file_inode(file);
+ struct hot_info *root = inode->i_sb->s_hot_root;
+ struct hot_heat_info heat_info;
+ struct hot_inode_item *he;
+ int ret = 0;
+
+ /* The 'live' field need to be read from the user space */
+ if (copy_from_user((void *)&heat_info,
+ argp,
+ sizeof(struct hot_heat_info)) != 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ he = hot_inode_item_lookup(root, inode->i_ino);
+ if (IS_ERR(he)) {
+ /* we don't have any info on this file yet */
+ ret = -ENODATA;
+ goto err;
+ }
+
+ heat_info.avg_delta_reads =
+ (__u64) he->freq.avg_delta_reads;
+ heat_info.avg_delta_writes =
+ (__u64) he->freq.avg_delta_writes;
+ heat_info.last_read_time =
+ (__u64) timespec_to_ns(&he->freq.last_read_time);
+ heat_info.last_write_time =
+ (__u64) timespec_to_ns(&he->freq.last_write_time);
+ heat_info.num_reads = (__u32) he->freq.nr_reads;
+ heat_info.num_writes = (__u32) he->freq.nr_writes;
+
+ if (heat_info.live > 0) {
+ /*
+ * got a request for live temperature,
+ * call hot_calc_temp() to recalculate
+ */
+ heat_info.temp = hot_temp_calc(&he->freq);
+ } else {
+ /* not live temperature, get it from the map list */
+ heat_info.temp = he->freq.last_temp;
+ }
+
+ spin_lock(&root->t_lock);
+ hot_inode_item_put(he);
+ spin_unlock(&root->t_lock);
+
+ if (copy_to_user(argp, (void *)&heat_info,
+ sizeof(struct hot_heat_info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+err:
+ return ret;
+}
+
+/*
* When you add any new common ioctls to the switches above and below
* please update compat_sys_ioctl() too.
*
@@ -591,6 +659,9 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
case FIGETBSZ:
return put_user(inode->i_sb->s_blocksize, argp);

+ case FS_IOC_GET_HEAT_INFO:
+ return ioctl_heat_info(filp, argp);
+
default:
if (S_ISREG(inode->i_mode))
error = file_ioctl(filp, cmd, arg);
diff --git a/include/linux/hot_tracking.h b/include/linux/hot_tracking.h
index 67468a51..0ee9ca2 100644
--- a/include/linux/hot_tracking.h
+++ b/include/linux/hot_tracking.h
@@ -15,11 +15,11 @@
#ifndef _LINUX_HOTTRACK_H
#define _LINUX_HOTTRACK_H

-#include <linux/types.h>
#include <linux/slab.h>
#include <linux/rbtree.h>
#include <linux/kref.h>
#include <linux/fs.h>
+#include <uapi/linux/hot_tracking.h>

#define MAP_BITS 8
#define MAP_SIZE (1 << MAP_BITS)
@@ -85,6 +85,14 @@ struct hot_info {
struct shrinker hot_shrink;
};

+/*
+ * Hot data tracking ioctls:
+ *
+ * HOT_INFO - retrieve info on frequency of access
+ */
+#define FS_IOC_GET_HEAT_INFO _IOR('f', 17, \
+ struct hot_heat_info)
+
extern int hot_track_init(struct super_block *sb);
extern void hot_track_exit(struct super_block *sb);
extern void hot_freqs_update(struct inode *inode, loff_t start,
diff --git a/include/uapi/linux/hot_tracking.h b/include/uapi/linux/hot_tracking.h
new file mode 100644
index 0000000..09dfc00
--- /dev/null
+++ b/include/uapi/linux/hot_tracking.h
@@ -0,0 +1,33 @@
+/*
+ * include/uapi/linux/hot_tracking.h
+ *
+ * This file has definitions for VFS hot tracking
+ * structures etc.
+ *
+ * Copyright (C) 2013 IBM Corp. All rights reserved.
+ * Written by Zhi Yong Wu <wuzhy@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 _UAPI_HOTTRACK_H
+#define _UAPI_HOTTRACK_H
+
+#include <linux/types.h>
+
+struct hot_heat_info {
+ __u8 live;
+ __u8 resv[3];
+ __u32 temp;
+ __u64 avg_delta_reads;
+ __u64 avg_delta_writes;
+ __u64 last_read_time;
+ __u64 last_write_time;
+ __u32 num_reads;
+ __u32 num_writes;
+ __u64 future[4]; /* For future expansions */
+};
+
+#endif /* _UAPI_HOTTRACK_H */
--
1.7.11.7