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[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23

Browse source 
Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
Jens Axboe 2006-03-23 20:00:26 +01:00
parent 6dac40a7ce
commit 2056a782f8
17 changed files with 916 additions and 3 deletions
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12
block/Kconfig
View file

@ -11,4 +11,16 @@ config LBD
your machine, or if you want to have a raid or loopback device
bigger than 2TB. Otherwise say N.
config BLK_DEV_IO_TRACE
bool "Support for tracing block io actions"
select RELAY
select DEBUG_FS
help
Say Y here, if you want to be able to trace the block layer actions
on a given queue. Tracing allows you to see any traffic happening
on a block device queue. For more information (and the user space
support tools needed), fetch the blktrace app from:
git://brick.kernel.dk/data/git/blktrace.git
source block/Kconfig.iosched

2
block/Makefile
View file

@ -8,3 +8,5 @@ obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
obj-$(CONFIG_IOSCHED_AS) += as-iosched.o
obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
obj-$(CONFIG_BLK_DEV_IO_TRACE) += blktrace.o

538
block/blktrace.c Normal file
View file

@ -0,0 +1,538 @@
/*
* Copyright (C) 2006 Jens Axboe <axboe@suse.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/blktrace_api.h>
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
#include <asm/uaccess.h>
static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
static unsigned int blktrace_seq __read_mostly = 1;
/*
* Send out a notify for this process, if we haven't done so since a trace
* started
*/
static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
{
struct blk_io_trace *t;
t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm));
if (t) {
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->device = bt->dev;
t->action = BLK_TC_ACT(BLK_TC_NOTIFY);
t->pid = tsk->pid;
t->cpu = smp_processor_id();
t->pdu_len = sizeof(tsk->comm);
memcpy((void *) t + sizeof(*t), tsk->comm, t->pdu_len);
tsk->btrace_seq = blktrace_seq;
}
}
static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
pid_t pid)
{
if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
return 1;
if (sector < bt->start_lba || sector > bt->end_lba)
return 1;
if (bt->pid && pid != bt->pid)
return 1;
return 0;
}
/*
* Data direction bit lookup
*/
static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
/*
* Bio action bits of interest
*/
static u32 bio_act[3] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC) };
/*
* More could be added as needed, taking care to increment the decrementer
* to get correct indexing
*/
#define trace_barrier_bit(rw) \
(((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))
#define trace_sync_bit(rw) \
(((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))
/*
* The worker for the various blk_add_trace*() types. Fills out a
* blk_io_trace structure and places it in a per-cpu subbuffer.
*/
void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
int rw, u32 what, int error, int pdu_len, void *pdu_data)
{
struct task_struct *tsk = current;
struct blk_io_trace *t;
unsigned long flags;
unsigned long *sequence;
pid_t pid;
int cpu;
if (unlikely(bt->trace_state != Blktrace_running))
return;
what |= ddir_act[rw & WRITE];
what |= bio_act[trace_barrier_bit(rw)];
what |= bio_act[trace_sync_bit(rw)];
pid = tsk->pid;
if (unlikely(act_log_check(bt, what, sector, pid)))
return;
/*
* A word about the locking here - we disable interrupts to reserve
* some space in the relay per-cpu buffer, to prevent an irq
* from coming in and stepping on our toes. Once reserved, it's
* enough to get preemption disabled to prevent read of this data
* before we are through filling it. get_cpu()/put_cpu() does this
* for us
*/
local_irq_save(flags);
if (unlikely(tsk->btrace_seq != blktrace_seq))
trace_note_tsk(bt, tsk);
t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
if (t) {
cpu = smp_processor_id();
sequence = per_cpu_ptr(bt->sequence, cpu);
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->sequence = ++(*sequence);
t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
t->sector = sector;
t->bytes = bytes;
t->action = what;
t->pid = pid;
t->device = bt->dev;
t->cpu = cpu;
t->error = error;
t->pdu_len = pdu_len;
if (pdu_len)
memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
}
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(__blk_add_trace);
static struct dentry *blk_tree_root;
static struct mutex blk_tree_mutex;
static unsigned int root_users;
static inline void blk_remove_root(void)
{
if (blk_tree_root) {
debugfs_remove(blk_tree_root);
blk_tree_root = NULL;
}
}
static void blk_remove_tree(struct dentry *dir)
{
mutex_lock(&blk_tree_mutex);
debugfs_remove(dir);
if (--root_users == 0)
blk_remove_root();
mutex_unlock(&blk_tree_mutex);
}
static struct dentry *blk_create_tree(const char *blk_name)
{
struct dentry *dir = NULL;
mutex_lock(&blk_tree_mutex);
if (!blk_tree_root) {
blk_tree_root = debugfs_create_dir("block", NULL);
if (!blk_tree_root)
goto err;
}
dir = debugfs_create_dir(blk_name, blk_tree_root);
if (dir)
root_users++;
else
blk_remove_root();
err:
mutex_unlock(&blk_tree_mutex);
return dir;
}
static void blk_trace_cleanup(struct blk_trace *bt)
{
relay_close(bt->rchan);
debugfs_remove(bt->dropped_file);
blk_remove_tree(bt->dir);
free_percpu(bt->sequence);
kfree(bt);
}
static int blk_trace_remove(request_queue_t *q)
{
struct blk_trace *bt;
bt = xchg(&q->blk_trace, NULL);
if (!bt)
return -EINVAL;
if (bt->trace_state == Blktrace_setup ||
bt->trace_state == Blktrace_stopped)
blk_trace_cleanup(bt);
return 0;
}
static int blk_dropped_open(struct inode *inode, struct file *filp)
{
filp->private_data = inode->u.generic_ip;
return 0;
}
static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
size_t count, loff_t *ppos)
{
struct blk_trace *bt = filp->private_data;
char buf[16];
snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
}
static struct file_operations blk_dropped_fops = {
.owner = THIS_MODULE,
.open = blk_dropped_open,
.read = blk_dropped_read,
};
/*
* Keep track of how many times we encountered a full subbuffer, to aid
* the user space app in telling how many lost events there were.
*/
static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
void *prev_subbuf, size_t prev_padding)
{
struct blk_trace *bt;
if (!relay_buf_full(buf))
return 1;
bt = buf->chan->private_data;
atomic_inc(&bt->dropped);
return 0;
}
static int blk_remove_buf_file_callback(struct dentry *dentry)
{
debugfs_remove(dentry);
return 0;
}
static struct dentry *blk_create_buf_file_callback(const char *filename,
struct dentry *parent,
int mode,
struct rchan_buf *buf,
int *is_global)
{
return debugfs_create_file(filename, mode, parent, buf,
&relay_file_operations);
}
static struct rchan_callbacks blk_relay_callbacks = {
.subbuf_start = blk_subbuf_start_callback,
.create_buf_file = blk_create_buf_file_callback,
.remove_buf_file = blk_remove_buf_file_callback,
};
/*
* Setup everything required to start tracing
*/
static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
char __user *arg)
{
struct blk_user_trace_setup buts;
struct blk_trace *old_bt, *bt = NULL;
struct dentry *dir = NULL;
char b[BDEVNAME_SIZE];
int ret, i;
if (copy_from_user(&buts, arg, sizeof(buts)))
return -EFAULT;
if (!buts.buf_size || !buts.buf_nr)
return -EINVAL;
strcpy(buts.name, bdevname(bdev, b));
/*
* some device names have larger paths - convert the slashes
* to underscores for this to work as expected
*/
for (i = 0; i < strlen(buts.name); i++)
if (buts.name[i] == '/')
buts.name[i] = '_';
if (copy_to_user(arg, &buts, sizeof(buts)))
return -EFAULT;
ret = -ENOMEM;
bt = kzalloc(sizeof(*bt), GFP_KERNEL);
if (!bt)
goto err;
bt->sequence = alloc_percpu(unsigned long);
if (!bt->sequence)
goto err;
ret = -ENOENT;
dir = blk_create_tree(buts.name);
if (!dir)
goto err;
bt->dir = dir;
bt->dev = bdev->bd_dev;
atomic_set(&bt->dropped, 0);
ret = -EIO;
bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
if (!bt->dropped_file)
goto err;
bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks);
if (!bt->rchan)
goto err;
bt->rchan->private_data = bt;
bt->act_mask = buts.act_mask;
if (!bt->act_mask)
bt->act_mask = (u16) -1;
bt->start_lba = buts.start_lba;
bt->end_lba = buts.end_lba;
if (!bt->end_lba)
bt->end_lba = -1ULL;
bt->pid = buts.pid;
bt->trace_state = Blktrace_setup;
ret = -EBUSY;
old_bt = xchg(&q->blk_trace, bt);
if (old_bt) {
(void) xchg(&q->blk_trace, old_bt);
goto err;
}
return 0;
err:
if (dir)
blk_remove_tree(dir);
if (bt) {
if (bt->dropped_file)
debugfs_remove(bt->dropped_file);
if (bt->sequence)
free_percpu(bt->sequence);
if (bt->rchan)
relay_close(bt->rchan);
kfree(bt);
}
return ret;
}
static int blk_trace_startstop(request_queue_t *q, int start)
{
struct blk_trace *bt;
int ret;
if ((bt = q->blk_trace) == NULL)
return -EINVAL;
/*
* For starting a trace, we can transition from a setup or stopped
* trace. For stopping a trace, the state must be running
*/
ret = -EINVAL;
if (start) {
if (bt->trace_state == Blktrace_setup ||
bt->trace_state == Blktrace_stopped) {
blktrace_seq++;
smp_mb();
bt->trace_state = Blktrace_running;
ret = 0;
}
} else {
if (bt->trace_state == Blktrace_running) {
bt->trace_state = Blktrace_stopped;
relay_flush(bt->rchan);
ret = 0;
}
}
return ret;
}
/**
* blk_trace_ioctl: - handle the ioctls associated with tracing
* @bdev: the block device
* @cmd: the ioctl cmd
* @arg: the argument data, if any
*
**/
int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
{
request_queue_t *q;
int ret, start = 0;
q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
mutex_lock(&bdev->bd_mutex);
switch (cmd) {
case BLKTRACESETUP:
ret = blk_trace_setup(q, bdev, arg);
break;
case BLKTRACESTART:
start = 1;
case BLKTRACESTOP:
ret = blk_trace_startstop(q, start);
break;
case BLKTRACETEARDOWN:
ret = blk_trace_remove(q);
break;
default:
ret = -ENOTTY;
break;
}
mutex_unlock(&bdev->bd_mutex);
return ret;
}
/**
* blk_trace_shutdown: - stop and cleanup trace structures
* @q: the request queue associated with the device
*
**/
void blk_trace_shutdown(request_queue_t *q)
{
blk_trace_startstop(q, 0);
blk_trace_remove(q);
}
/*
* Average offset over two calls to sched_clock() with a gettimeofday()
* in the middle
*/
static void blk_check_time(unsigned long long *t)
{
unsigned long long a, b;
struct timeval tv;
a = sched_clock();
do_gettimeofday(&tv);
b = sched_clock();
*t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
*t -= (a + b) / 2;
}
static void blk_trace_check_cpu_time(void *data)
{
unsigned long long *t;
int cpu = get_cpu();
t = &per_cpu(blk_trace_cpu_offset, cpu);
/*
* Just call it twice, hopefully the second call will be cache hot
* and a little more precise
*/
blk_check_time(t);
blk_check_time(t);
put_cpu();
}
/*
* Call blk_trace_check_cpu_time() on each CPU to calibrate our inter-CPU
* timings
*/
static void blk_trace_calibrate_offsets(void)
{
unsigned long flags;
smp_call_function(blk_trace_check_cpu_time, NULL, 1, 1);
local_irq_save(flags);
blk_trace_check_cpu_time(NULL);
local_irq_restore(flags);
}
static void blk_trace_set_ht_offsets(void)
{
#if defined(CONFIG_SCHED_SMT)
int cpu, i;
/*
* now make sure HT siblings have the same time offset
*/
preempt_disable();
for_each_online_cpu(cpu) {
unsigned long long *cpu_off, *sibling_off;
for_each_cpu_mask(i, cpu_sibling_map[cpu]) {
if (i == cpu)
continue;
cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
sibling_off = &per_cpu(blk_trace_cpu_offset, i);
*sibling_off = *cpu_off;
}
}
preempt_enable();
#endif
}
static __init int blk_trace_init(void)
{
mutex_init(&blk_tree_mutex);
blk_trace_calibrate_offsets();
blk_trace_set_ht_offsets();
return 0;
}
module_init(blk_trace_init);

4
block/elevator.c
View file

@ -33,6 +33,7 @@
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/delay.h>
#include <linux/blktrace_api.h>
#include <asm/uaccess.h>
@ -333,6 +334,8 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
struct list_head *pos;
unsigned ordseq;
blk_add_trace_rq(q, rq, BLK_TA_INSERT);
rq->q = q;
switch (where) {
@ -499,6 +502,7 @@ struct request *elv_next_request(request_queue_t *q)
* not be passed by new incoming requests
*/
rq->flags |= REQ_STARTED;
blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
}
if (!q->boundary_rq || q->boundary_rq == rq) {

6
block/ioctl.c
View file

@ -5,6 +5,7 @@
#include <linux/backing-dev.h>
#include <linux/buffer_head.h>
#include <linux/smp_lock.h>
#include <linux/blktrace_api.h>
#include <asm/uaccess.h>
static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
@ -189,6 +190,11 @@ static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
return put_ulong(arg, bdev->bd_inode->i_size >> 9);
case BLKGETSIZE64:
return put_u64(arg, bdev->bd_inode->i_size);
case BLKTRACESTART:
case BLKTRACESTOP:
case BLKTRACESETUP:
case BLKTRACETEARDOWN:
return blk_trace_ioctl(bdev, cmd, (char __user *) arg);
}
return -ENOIOCTLCMD;
}

44
block/ll_rw_blk.c
View file

@ -28,6 +28,7 @@
#include <linux/writeback.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
/*
* for max sense size
@ -1556,8 +1557,10 @@ void blk_plug_device(request_queue_t *q)
if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
return;
if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
}
}
EXPORT_SYMBOL(blk_plug_device);
@ -1621,14 +1624,21 @@ static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
/*
* devices don't necessarily have an ->unplug_fn defined
*/
if (q->unplug_fn)
if (q->unplug_fn) {
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
q->rq.count[READ] + q->rq.count[WRITE]);
q->unplug_fn(q);
}
}
static void blk_unplug_work(void *data)
{
request_queue_t *q = data;
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
q->rq.count[READ] + q->rq.count[WRITE]);
q->unplug_fn(q);
}
@ -1636,6 +1646,9 @@ static void blk_unplug_timeout(unsigned long data)
{
request_queue_t *q = (request_queue_t *)data;
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
q->rq.count[READ] + q->rq.count[WRITE]);
kblockd_schedule_work(&q->unplug_work);
}
@ -1753,6 +1766,9 @@ static void blk_release_queue(struct kobject *kobj)
if (q->queue_tags)
__blk_queue_free_tags(q);
if (q->blk_trace)
blk_trace_shutdown(q);
kmem_cache_free(requestq_cachep, q);
}
@ -2129,6 +2145,8 @@ static struct request *get_request(request_queue_t *q, int rw, struct bio *bio,
rq_init(q, rq);
rq->rl = rl;
blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
out:
return rq;
}
@ -2157,6 +2175,8 @@ static struct request *get_request_wait(request_queue_t *q, int rw,
if (!rq) {
struct io_context *ioc;
blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
__generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
io_schedule();
@ -2210,6 +2230,8 @@ EXPORT_SYMBOL(blk_get_request);
*/
void blk_requeue_request(request_queue_t *q, struct request *rq)
{
blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
if (blk_rq_tagged(rq))
blk_queue_end_tag(q, rq);
@ -2844,6 +2866,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
if (!q->back_merge_fn(q, req, bio))
break;
blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
req->biotail->bi_next = bio;
req->biotail = bio;
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
@ -2859,6 +2883,8 @@ static int __make_request(request_queue_t *q, struct bio *bio)
if (!q->front_merge_fn(q, req, bio))
break;
blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
bio->bi_next = req->bio;
req->bio = bio;
@ -2976,6 +3002,7 @@ void generic_make_request(struct bio *bio)
request_queue_t *q;
sector_t maxsector;
int ret, nr_sectors = bio_sectors(bio);
dev_t old_dev;
might_sleep();
/* Test device or partition size, when known. */
@ -3002,6 +3029,8 @@ void generic_make_request(struct bio *bio)
* NOTE: we don't repeat the blk_size check for each new device.
* Stacking drivers are expected to know what they are doing.
*/
maxsector = -1;
old_dev = 0;
do {
char b[BDEVNAME_SIZE];
@ -3034,6 +3063,15 @@ void generic_make_request(struct bio *bio)
*/
blk_partition_remap(bio);
if (maxsector != -1)
blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
maxsector);
blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
maxsector = bio->bi_sector;
old_dev = bio->bi_bdev->bd_dev;
ret = q->make_request_fn(q, bio);
} while (ret);
}
@ -3153,6 +3191,8 @@ static int __end_that_request_first(struct request *req, int uptodate,
int total_bytes, bio_nbytes, error, next_idx = 0;
struct bio *bio;
blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
/*
* extend uptodate bool to allow < 0 value to be direct io error
*/

2
drivers/block/cciss.c
View file

@ -38,6 +38,7 @@
#include <linux/hdreg.h>
#include <linux/spinlock.h>
#include <linux/compat.h>
#include <linux/blktrace_api.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@ -2331,6 +2332,7 @@ static inline void complete_command( ctlr_info_t *h, CommandList_struct *cmd,
cmd->rq->completion_data = cmd;
cmd->rq->errors = status;
blk_add_trace_rq(cmd->rq->q, cmd->rq, BLK_TA_COMPLETE);
blk_complete_request(cmd->rq);
}

13
drivers/md/dm.c
View file

@ -17,6 +17,7 @@
#include <linux/mempool.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/blktrace_api.h>
static const char *_name = DM_NAME;
@ -334,6 +335,8 @@ static void dec_pending(struct dm_io *io, int error)
/* nudge anyone waiting on suspend queue */
wake_up(&io->md->wait);
blk_add_trace_bio(io->md->queue, io->bio, BLK_TA_COMPLETE);
bio_endio(io->bio, io->bio->bi_size, io->error);
free_io(io->md, io);
}
@ -392,6 +395,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
struct target_io *tio)
{
int r;
sector_t sector;
/*
* Sanity checks.
@ -407,10 +411,17 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
* this io.
*/
atomic_inc(&tio->io->io_count);
sector = clone->bi_sector;
r = ti->type->map(ti, clone, &tio->info);
if (r > 0)
if (r > 0) {
/* the bio has been remapped so dispatch it */
blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
tio->io->bio->bi_bdev->bd_dev, sector,
clone->bi_sector);
generic_make_request(clone);
}
else if (r < 0) {
/* error the io and bail out */

4
fs/bio.c
View file

@ -25,6 +25,7 @@
#include <linux/module.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
#include <linux/blktrace_api.h>
#include <scsi/sg.h> /* for struct sg_iovec */
#define BIO_POOL_SIZE 256
@ -1095,6 +1096,9 @@ struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
if (!bp)
return bp;
blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
bi->bi_sector + first_sectors);
BUG_ON(bi->bi_vcnt != 1);
BUG_ON(bi->bi_idx != 0);
atomic_set(&bp->cnt, 3);

1
fs/compat_ioctl.c
View file

@ -72,6 +72,7 @@
#include <linux/i2c-dev.h>
#include <linux/wireless.h>
#include <linux/atalk.h>
#include <linux/blktrace_api.h>
#include <net/sock.h> /* siocdevprivate_ioctl */
#include <net/bluetooth/bluetooth.h>

3
include/linux/blkdev.h
View file

@ -22,6 +22,7 @@ typedef struct request_queue request_queue_t;
struct elevator_queue;
typedef struct elevator_queue elevator_t;
struct request_pm_state;
struct blk_trace;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
@ -416,6 +417,8 @@ struct request_queue
unsigned int sg_reserved_size;
int node;
struct blk_trace *blk_trace;
/*
* reserved for flush operations
*/

277
include/linux/blktrace_api.h Normal file
View file

@ -0,0 +1,277 @@
#ifndef BLKTRACE_H
#define BLKTRACE_H
#include <linux/config.h>
#include <linux/blkdev.h>
#include <linux/relay.h>
/*
* Trace categories
*/
enum blktrace_cat {
BLK_TC_READ = 1 << 0, /* reads */
BLK_TC_WRITE = 1 << 1, /* writes */
BLK_TC_BARRIER = 1 << 2, /* barrier */
BLK_TC_SYNC = 1 << 3, /* barrier */
BLK_TC_QUEUE = 1 << 4, /* queueing/merging */
BLK_TC_REQUEUE = 1 << 5, /* requeueing */
BLK_TC_ISSUE = 1 << 6, /* issue */
BLK_TC_COMPLETE = 1 << 7, /* completions */
BLK_TC_FS = 1 << 8, /* fs requests */
BLK_TC_PC = 1 << 9, /* pc requests */
BLK_TC_NOTIFY = 1 << 10, /* special message */
BLK_TC_END = 1 << 15, /* only 16-bits, reminder */
};
#define BLK_TC_SHIFT (16)
#define BLK_TC_ACT(act) ((act) << BLK_TC_SHIFT)
/*
* Basic trace actions
*/
enum blktrace_act {
__BLK_TA_QUEUE = 1, /* queued */
__BLK_TA_BACKMERGE, /* back merged to existing rq */
__BLK_TA_FRONTMERGE, /* front merge to existing rq */
__BLK_TA_GETRQ, /* allocated new request */
__BLK_TA_SLEEPRQ, /* sleeping on rq allocation */
__BLK_TA_REQUEUE, /* request requeued */
__BLK_TA_ISSUE, /* sent to driver */
__BLK_TA_COMPLETE, /* completed by driver */
__BLK_TA_PLUG, /* queue was plugged */
__BLK_TA_UNPLUG_IO, /* queue was unplugged by io */
__BLK_TA_UNPLUG_TIMER, /* queue was unplugged by timer */
__BLK_TA_INSERT, /* insert request */
__BLK_TA_SPLIT, /* bio was split */
__BLK_TA_BOUNCE, /* bio was bounced */
__BLK_TA_REMAP, /* bio was remapped */
};
/*
* Trace actions in full. Additionally, read or write is masked
*/
#define BLK_TA_QUEUE (__BLK_TA_QUEUE | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_BACKMERGE (__BLK_TA_BACKMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_FRONTMERGE (__BLK_TA_FRONTMERGE | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_GETRQ (__BLK_TA_GETRQ | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_SLEEPRQ (__BLK_TA_SLEEPRQ | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_REQUEUE (__BLK_TA_REQUEUE | BLK_TC_ACT(BLK_TC_REQUEUE))
#define BLK_TA_ISSUE (__BLK_TA_ISSUE | BLK_TC_ACT(BLK_TC_ISSUE))
#define BLK_TA_COMPLETE (__BLK_TA_COMPLETE| BLK_TC_ACT(BLK_TC_COMPLETE))
#define BLK_TA_PLUG (__BLK_TA_PLUG | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_UNPLUG_IO (__BLK_TA_UNPLUG_IO | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_UNPLUG_TIMER (__BLK_TA_UNPLUG_TIMER | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_INSERT (__BLK_TA_INSERT | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_TA_SPLIT (__BLK_TA_SPLIT)
#define BLK_TA_BOUNCE (__BLK_TA_BOUNCE)
#define BLK_TA_REMAP (__BLK_TA_REMAP | BLK_TC_ACT(BLK_TC_QUEUE))
#define BLK_IO_TRACE_MAGIC 0x65617400
#define BLK_IO_TRACE_VERSION 0x07
/*
* The trace itself
*/
struct blk_io_trace {
u32 magic; /* MAGIC << 8 | version */
u32 sequence; /* event number */
u64 time; /* in microseconds */
u64 sector; /* disk offset */
u32 bytes; /* transfer length */
u32 action; /* what happened */
u32 pid; /* who did it */
u32 device; /* device number */
u32 cpu; /* on what cpu did it happen */
u16 error; /* completion error */
u16 pdu_len; /* length of data after this trace */
};
/*
* The remap event
*/
struct blk_io_trace_remap {
u32 device;
u32 __pad;
u64 sector;
};
enum {
Blktrace_setup = 1,
Blktrace_running,
Blktrace_stopped,
};
struct blk_trace {
int trace_state;
struct rchan *rchan;
unsigned long *sequence;
u16 act_mask;
u64 start_lba;
u64 end_lba;
u32 pid;
u32 dev;
struct dentry *dir;
struct dentry *dropped_file;
atomic_t dropped;
};
/*
* User setup structure passed with BLKTRACESTART
*/
struct blk_user_trace_setup {
char name[BDEVNAME_SIZE]; /* output */
u16 act_mask; /* input */
u32 buf_size; /* input */
u32 buf_nr; /* input */
u64 start_lba;
u64 end_lba;
u32 pid;
};
#if defined(CONFIG_BLK_DEV_IO_TRACE)
extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
extern void blk_trace_shutdown(request_queue_t *);
extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
/**
* blk_add_trace_rq - Add a trace for a request oriented action
* @q: queue the io is for
* @rq: the source request
* @what: the action
*
* Description:
* Records an action against a request. Will log the bio offset + size.
*
**/
static inline void blk_add_trace_rq(struct request_queue *q, struct request *rq,
u32 what)
{
struct blk_trace *bt = q->blk_trace;
int rw = rq->flags & 0x07;
if (likely(!bt))
return;
if (blk_pc_request(rq)) {
what |= BLK_TC_ACT(BLK_TC_PC);
__blk_add_trace(bt, 0, rq->data_len, rw, what, rq->errors, sizeof(rq->cmd), rq->cmd);
} else {
what |= BLK_TC_ACT(BLK_TC_FS);
__blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9, rw, what, rq->errors, 0, NULL);
}
}
/**
* blk_add_trace_bio - Add a trace for a bio oriented action
* @q: queue the io is for
* @bio: the source bio
* @what: the action
*
* Description:
* Records an action against a bio. Will log the bio offset + size.
*
**/
static inline void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
u32 what)
{
struct blk_trace *bt = q->blk_trace;
if (likely(!bt))
return;
__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
}
/**
* blk_add_trace_generic - Add a trace for a generic action
* @q: queue the io is for
* @bio: the source bio
* @rw: the data direction
* @what: the action
*
* Description:
* Records a simple trace
*
**/
static inline void blk_add_trace_generic(struct request_queue *q,
struct bio *bio, int rw, u32 what)
{
struct blk_trace *bt = q->blk_trace;
if (likely(!bt))
return;
if (bio)
blk_add_trace_bio(q, bio, what);
else
__blk_add_trace(bt, 0, 0, rw, what, 0, 0, NULL);
}
/**
* blk_add_trace_pdu_int - Add a trace for a bio with an integer payload
* @q: queue the io is for
* @what: the action
* @bio: the source bio
* @pdu: the integer payload
*
* Description:
* Adds a trace with some integer payload. This might be an unplug
* option given as the action, with the depth at unplug time given
* as the payload
*
**/
static inline void blk_add_trace_pdu_int(struct request_queue *q, u32 what,
struct bio *bio, unsigned int pdu)
{
struct blk_trace *bt = q->blk_trace;
u64 rpdu = cpu_to_be64(pdu);
if (likely(!bt))
return;
if (bio)
__blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what, !bio_flagged(bio, BIO_UPTODATE), sizeof(rpdu), &rpdu);
else
__blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu);
}
/**
* blk_add_trace_remap - Add a trace for a remap operation
* @q: queue the io is for
* @bio: the source bio
* @dev: target device
* @from: source sector
* @to: target sector
*
* Description:
* Device mapper or raid target sometimes need to split a bio because
* it spans a stripe (or similar). Add a trace for that action.
*
**/
static inline void blk_add_trace_remap(struct request_queue *q, struct bio *bio,
dev_t dev, sector_t from, sector_t to)
{
struct blk_trace *bt = q->blk_trace;
struct blk_io_trace_remap r;
if (likely(!bt))
return;
r.device = cpu_to_be32(dev);
r.sector = cpu_to_be64(to);
__blk_add_trace(bt, from, bio->bi_size, bio->bi_rw, BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE), sizeof(r), &r);
}
#else /* !CONFIG_BLK_DEV_IO_TRACE */
#define blk_trace_ioctl(bdev, cmd, arg) (-ENOTTY)
#define blk_trace_shutdown(q) do { } while (0)
#define blk_add_trace_rq(q, rq, what) do { } while (0)
#define blk_add_trace_bio(q, rq, what) do { } while (0)
#define blk_add_trace_generic(q, rq, rw, what) do { } while (0)
#define blk_add_trace_pdu_int(q, what, bio, pdu) do { } while (0)
#define blk_add_trace_remap(q, bio, dev, f, t) do {} while (0)
#endif /* CONFIG_BLK_DEV_IO_TRACE */
#endif

4
include/linux/compat_ioctl.h
View file

@ -97,6 +97,10 @@ COMPATIBLE_IOCTL(BLKRRPART)
COMPATIBLE_IOCTL(BLKFLSBUF)
COMPATIBLE_IOCTL(BLKSECTSET)
COMPATIBLE_IOCTL(BLKSSZGET)
COMPATIBLE_IOCTL(BLKTRACESTART)
COMPATIBLE_IOCTL(BLKTRACESTOP)
COMPATIBLE_IOCTL(BLKTRACESETUP)
COMPATIBLE_IOCTL(BLKTRACETEARDOWN)
ULONG_IOCTL(BLKRASET)
ULONG_IOCTL(BLKFRASET)
/* RAID */

4
include/linux/fs.h
View file

@ -197,6 +197,10 @@ extern int dir_notify_enable;
#define BLKBSZGET _IOR(0x12,112,size_t)
#define BLKBSZSET _IOW(0x12,113,size_t)
#define BLKGETSIZE64 _IOR(0x12,114,size_t) /* return device size in bytes (u64 *arg) */
#define BLKTRACESETUP _IOWR(0x12,115,struct blk_user_trace_setup)
#define BLKTRACESTART _IO(0x12,116)
#define BLKTRACESTOP _IO(0x12,117)
#define BLKTRACETEARDOWN _IO(0x12,118)
#define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
#define FIBMAP _IO(0x00,1) /* bmap access */

1
include/linux/sched.h
View file

@ -706,6 +706,7 @@ struct task_struct {
prio_array_t *array;
unsigned short ioprio;
unsigned int btrace_seq;
unsigned long sleep_avg;
unsigned long long timestamp, last_ran;

1
kernel/fork.c
View file

@ -181,6 +181,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
/* One for us, one for whoever does the "release_task()" (usually parent) */
atomic_set(&tsk->usage,2);
atomic_set(&tsk->fs_excl, 0);
tsk->btrace_seq = 0;
return tsk;
}

3
mm/highmem.c
View file

@ -26,6 +26,7 @@
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/blktrace_api.h>
#include <asm/tlbflush.h>
static mempool_t *page_pool, *isa_page_pool;
@ -483,6 +484,8 @@ void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig)
pool = isa_page_pool;
}
blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
/*
* slow path
*/