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authorJens Axboe <axboe@suse.de>2006-03-23 20:00:26 +0100
committerJens Axboe <axboe@suse.de>2006-03-23 20:00:26 +0100
commit2056a782f8e7e65fd4bfd027506b4ce1c5e9ccd4 (patch)
treed4fe59a7ca0c110690937085548936a4535c39db
parent6dac40a7ce2483a47b54af07afebeb84131c7228 (diff)
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[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23
Signed-off-by: Jens Axboe <axboe@suse.de>
-rw-r--r--block/Kconfig12
-rw-r--r--block/Makefile2
-rw-r--r--block/blktrace.c538
-rw-r--r--block/elevator.c4
-rw-r--r--block/ioctl.c6
-rw-r--r--block/ll_rw_blk.c44
-rw-r--r--drivers/block/cciss.c2
-rw-r--r--drivers/md/dm.c13
-rw-r--r--fs/bio.c4
-rw-r--r--fs/compat_ioctl.c1
-rw-r--r--include/linux/blkdev.h3
-rw-r--r--include/linux/blktrace_api.h277
-rw-r--r--include/linux/compat_ioctl.h4
-rw-r--r--include/linux/fs.h4
-rw-r--r--include/linux/sched.h1
-rw-r--r--kernel/fork.c1
-rw-r--r--mm/highmem.c3
17 files changed, 916 insertions, 3 deletions
diff --git a/block/Kconfig b/block/Kconfig
index 377f6dd20e1..96783645092 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -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
diff --git a/block/Makefile b/block/Makefile
index 7e4f93e2b44..c05de0e0037 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -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
diff --git a/block/blktrace.c b/block/blktrace.c
new file mode 100644
index 00000000000..36f3a172275
--- /dev/null
+++ b/block/blktrace.c
@@ -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);
+
diff --git a/block/elevator.c b/block/elevator.c
index db3d0d8296a..5e558c4689a 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -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) {
diff --git a/block/ioctl.c b/block/ioctl.c
index 35fdb7dc651..9cfa2e1ecb2 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -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;
}
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 6c793b196aa..062067fa7ea 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -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 @@ rq_starved:
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 @@ end_io:
*/
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
*/
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index e29b8926f80..1f2890989b5 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -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);
}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 26b08ee425c..8c82373f7ff 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -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 */
diff --git a/fs/bio.c b/fs/bio.c
index 8f1d2e815c9..0a8c59cb68f 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -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);
diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index c666769a875..7c031f00fd7 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -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>
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 56bb6a4e15f..c179966f1a2 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -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
*/
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
new file mode 100644
index 00000000000..b34d3e73d5e
--- /dev/null
+++ b/include/linux/blktrace_api.h
@@ -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
diff --git a/include/linux/compat_ioctl.h b/include/linux/compat_ioctl.h
index ae7dfb790df..efb518f16bb 100644
--- a/include/linux/compat_ioctl.h
+++ b/include/linux/compat_ioctl.h
@@ -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 */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index f9c9dea636d..9b34a1b0345 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -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 */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 62e6314382f..e60a91d5b36 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -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;
diff --git a/kernel/fork.c b/kernel/fork.c
index c79ae0b19a4..c21bae8c93b 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -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;
}
diff --git a/mm/highmem.c b/mm/highmem.c
index ce2e7e8bbfa..d0ea1eec6a9 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -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
*/