Re: [PATCH][v2] blktrace: conversion to tracepoints

Mathieu Desnoyers
2008-10-29T15:18:12Z

* Arnaldo Carvalho de Melo (acme@redhat.com) wrote:
> Hi Jens,
>
> Now that the tracepoints infrastructure is merged I updated the
> patch, please take a look.
>
> One suggestion I got was to have things like:
>
> trace_block_unplug_io(q, q->rq.count[READ] + q->rq.count[WRITE]);
>
> That was:
>
> blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
> q->rq.count[READ] + q->rq.count[WRITE]);
>
> To be:
>
> trace_block_unplug_io(q, q->rq.count[READ], q->rq.count[WRITE]);
>
> Or even:
>
> trace_block_unplug_io(q);
>

Hi Arnaldo,

The quick answer to this is : look at the assembly generated by these
alternatives. You will notice that some calculation required to populate
the stack required for the tracepoint function call might fall outside
of the if (unlikely()) check. This wasn't the case with markers because
I could embed it in a macro, but I really have to use an inline function
for tracepoints.

Therefore, the way to make sure no calculation whatsoever is done when
tracepoints are disabled is to simply pass "q" as parameter. But feel
free to compare the assembly output of the different alternatives.

Regards,

Mathieu

> And on blk_add_trace_unplug_io tracepoint do the math and feed
> it to __blk_add_trace.
>
> So that the information on the number of types of requests
> instead of the sum, what do you think? Overengineering? For blktrace it
> would end up being preserved as is in, say:
>
> static void blk_add_trace_unplug_io(struct request_queue *q,
> unsigned int rd, unsigned int wr)
> {
> struct blk_trace *bt = q->blk_trace;
>
> if (bt) {
> __be64 rpdu = cpu_to_be64(rd + wr);
>
> __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
> sizeof(rpdu), &rpdu);
> }
> }
>
> Perhaps doing it as 'trace_block_unplug_io(q)' would be the best
> scenario, as the tracepoint user can look at struct_request queue at
> will anyway and the code gets cleaner :-)
>
> Feel free to point any disgusting aspect, perhaps there is at
> least one to warn me about fixing 8-)
>
> Regards,
>
> - Arnaldo
>
> commit c9dafb929ce719ead4b030e7d19c06719e97c3a1
> Author: Arnaldo Carvalho de Melo <acme@redhat.com>
> Date: Wed Oct 29 10:05:09 2008 -0200
>
> blktrace: port to tracepoints
>
> This was a forward port of work done by Mathieu Desnoyers, I changed it to
> encode the 'what' parameter on the tracepoint name, so that one can register
> interest in specific events and not on classes of events to then check the
> 'what' parameter.
>
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
>
> diff --git a/block/Kconfig b/block/Kconfig
> index 1ab7c15..290b219 100644
> --- a/block/Kconfig
> +++ b/block/Kconfig
> @@ -47,6 +47,7 @@ config BLK_DEV_IO_TRACE
> depends on SYSFS
> select RELAY
> select DEBUG_FS
> + select TRACEPOINTS
> 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
> diff --git a/block/blk-core.c b/block/blk-core.c
> index c3df30c..bfd3083 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -28,6 +28,7 @@
> #include <linux/task_io_accounting_ops.h>
> #include <linux/blktrace_api.h>
> #include <linux/fault-inject.h>
> +#include <trace/block.h>
>
> #include "blk.h"
>
> @@ -205,7 +206,7 @@ void blk_plug_device(struct request_queue *q)
>
> if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) {
> mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
> - blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
> + trace_block_plug(q);
> }
> }
> EXPORT_SYMBOL(blk_plug_device);
> @@ -292,8 +293,7 @@ void blk_unplug_work(struct work_struct *work)
> struct request_queue *q =
> container_of(work, struct request_queue, unplug_work);
>
> - blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
> - q->rq.count[READ] + q->rq.count[WRITE]);
> + trace_block_unplug_io(q, q->rq.count[READ] + q->rq.count[WRITE]);
>
> q->unplug_fn(q);
> }
> @@ -302,8 +302,7 @@ void blk_unplug_timeout(unsigned long data)
> {
> struct request_queue *q = (struct request_queue *)data;
>
> - blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
> - q->rq.count[READ] + q->rq.count[WRITE]);
> + trace_block_unplug_timer(q, q->rq.count[READ] + q->rq.count[WRITE]);
>
> kblockd_schedule_work(q, &q->unplug_work);
> }
> @@ -314,8 +313,8 @@ void blk_unplug(struct request_queue *q)
> * devices don't necessarily have an ->unplug_fn defined
> */
> if (q->unplug_fn) {
> - blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
> - q->rq.count[READ] + q->rq.count[WRITE]);
> + trace_block_unplug_io(q, (q->rq.count[READ] +
> + q->rq.count[WRITE]));
>
> q->unplug_fn(q);
> }
> @@ -822,7 +821,7 @@ rq_starved:
> if (ioc_batching(q, ioc))
> ioc->nr_batch_requests--;
>
> - blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
> + trace_block_getrq(q, bio, rw);
> out:
> return rq;
> }
> @@ -848,7 +847,7 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
> prepare_to_wait_exclusive(&rl->wait[rw], &wait,
> TASK_UNINTERRUPTIBLE);
>
> - blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
> + trace_block_sleeprq(q, bio, rw);
>
> __generic_unplug_device(q);
> spin_unlock_irq(q->queue_lock);
> @@ -928,7 +927,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
> {
> blk_delete_timer(rq);
> blk_clear_rq_complete(rq);
> - blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
> + trace_block_rq_requeue(q, rq);
>
> if (blk_rq_tagged(rq))
> blk_queue_end_tag(q, rq);
> @@ -1167,7 +1166,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
> if (!ll_back_merge_fn(q, req, bio))
> break;
>
> - blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
> + trace_block_bio_backmerge(q, bio);
>
> req->biotail->bi_next = bio;
> req->biotail = bio;
> @@ -1186,7 +1185,7 @@ static int __make_request(struct request_queue *q, struct bio *bio)
> if (!ll_front_merge_fn(q, req, bio))
> break;
>
> - blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
> + trace_block_bio_frontmerge(q, bio);
>
> bio->bi_next = req->bio;
> req->bio = bio;
> @@ -1269,7 +1268,7 @@ static inline void blk_partition_remap(struct bio *bio)
> bio->bi_sector += p->start_sect;
> bio->bi_bdev = bdev->bd_contains;
>
> - blk_add_trace_remap(bdev_get_queue(bio->bi_bdev), bio,
> + trace_block_remap(bdev_get_queue(bio->bi_bdev), bio,
> bdev->bd_dev, bio->bi_sector,
> bio->bi_sector - p->start_sect);
> }
> @@ -1441,10 +1440,10 @@ end_io:
> goto end_io;
>
> if (old_sector != -1)
> - blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
> + trace_block_remap(q, bio, old_dev, bio->bi_sector,
> old_sector);
>
> - blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
> + trace_block_bio_queue(q, bio);
>
> old_sector = bio->bi_sector;
> old_dev = bio->bi_bdev->bd_dev;
> @@ -1656,7 +1655,7 @@ static int __end_that_request_first(struct request *req, int error,
> int total_bytes, bio_nbytes, next_idx = 0;
> struct bio *bio;
>
> - blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
> + trace_block_rq_complete(req->q, req);
>
> /*
> * for a REQ_TYPE_BLOCK_PC request, we want to carry any eventual
> diff --git a/block/blktrace.c b/block/blktrace.c
> index 85049a7..7f41123 100644
> --- a/block/blktrace.c
> +++ b/block/blktrace.c
> @@ -23,10 +23,18 @@
> #include <linux/mutex.h>
> #include <linux/debugfs.h>
> #include <linux/time.h>
> +#include <trace/block.h>
> #include <asm/uaccess.h>
>
> static unsigned int blktrace_seq __read_mostly = 1;
>
> +/* Global reference count of probes */
> +static DEFINE_MUTEX(blk_probe_mutex);
> +static int blk_probes_ref;
> +
> +static int blk_register_tracepoints(void);
> +static void blk_unregister_tracepoints(void);
> +
> /*
> * Send out a notify message.
> */
> @@ -119,7 +127,7 @@ static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK
> * 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,
> +static 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;
> @@ -177,8 +185,6 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
> local_irq_restore(flags);
> }
>
> -EXPORT_SYMBOL_GPL(__blk_add_trace);
> -
> static struct dentry *blk_tree_root;
> static DEFINE_MUTEX(blk_tree_mutex);
> static unsigned int root_users;
> @@ -237,6 +243,10 @@ static void blk_trace_cleanup(struct blk_trace *bt)
> free_percpu(bt->sequence);
> free_percpu(bt->msg_data);
> kfree(bt);
> + mutex_lock(&blk_probe_mutex);
> + if (--blk_probes_ref == 0)
> + blk_unregister_tracepoints();
> + mutex_unlock(&blk_probe_mutex);
> }
>
> int blk_trace_remove(struct request_queue *q)
> @@ -428,6 +438,14 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
> bt->pid = buts->pid;
> bt->trace_state = Blktrace_setup;
>
> + mutex_lock(&blk_probe_mutex);
> + if (!blk_probes_ref++) {
> + ret = blk_register_tracepoints();
> + if (ret)
> + goto probe_err;
> + }
> + mutex_unlock(&blk_probe_mutex);
> +
> ret = -EBUSY;
> old_bt = xchg(&q->blk_trace, bt);
> if (old_bt) {
> @@ -436,6 +454,9 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
> }
>
> return 0;
> +probe_err:
> + --blk_probes_ref;
> + mutex_unlock(&blk_probe_mutex);
> err:
> if (dir)
> blk_remove_tree(dir);
> @@ -562,3 +583,306 @@ void blk_trace_shutdown(struct request_queue *q)
> blk_trace_remove(q);
> }
> }
> +
> +/*
> + * blktrace probes
> + */
> +
> +/**
> + * 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 void blk_add_trace_rq(struct request_queue *q, struct request *rq,
> + u32 what)
> +{
> + struct blk_trace *bt = q->blk_trace;
> + int rw = rq->cmd_flags & 0x03;
> +
> + if (likely(!bt))
> + return;
> +
> + if (blk_discard_rq(rq))
> + rw |= (1 << BIO_RW_DISCARD);
> +
> + 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);
> + }
> +}
> +
> +static void blk_add_trace_rq_abort(struct request_queue *q, struct request *rq)
> +{
> + blk_add_trace_rq(q, rq, BLK_TA_ABORT);
> +}
> +
> +static void blk_add_trace_rq_insert(struct request_queue *q, struct request *rq)
> +{
> + blk_add_trace_rq(q, rq, BLK_TA_INSERT);
> +}
> +
> +static void blk_add_trace_rq_issue(struct request_queue *q, struct request *rq)
> +{
> + blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
> +}
> +
> +static void blk_add_trace_rq_requeue(struct request_queue *q, struct request *rq)
> +{
> + blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
> +}
> +
> +static void blk_add_trace_rq_complete(struct request_queue *q, struct request *rq)
> +{
> + blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
> +}
> +
> +/**
> + * 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 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);
> +}
> +
> +static void blk_add_trace_bio_bounce(struct request_queue *q, struct bio *bio)
> +{
> + blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
> +}
> +
> +static void blk_add_trace_bio_complete(struct request_queue *q, struct bio *bio)
> +{
> + blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
> +}
> +
> +static void blk_add_trace_bio_backmerge(struct request_queue *q, struct bio *bio)
> +{
> + blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
> +}
> +
> +static void blk_add_trace_bio_frontmerge(struct request_queue *q, struct bio *bio)
> +{
> + blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
> +}
> +
> +static void blk_add_trace_bio_queue(struct request_queue *q, struct bio *bio)
> +{
> + blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
> +}
> +
> +static void blk_add_trace_getrq(struct request_queue *q, struct bio *bio, int rw)
> +{
> + if (bio)
> + blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
> + else {
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt)
> + __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
> + }
> +}
> +
> +
> +static void blk_add_trace_sleeprq(struct request_queue *q, struct bio *bio, int rw)
> +{
> + if (bio)
> + blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
> + else {
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt)
> + __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ, 0, 0, NULL);
> + }
> +}
> +
> +static void blk_add_trace_plug(struct request_queue *q)
> +{
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt)
> + __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
> +}
> +
> +static void blk_add_trace_unplug_io(struct request_queue *q, unsigned int pdu)
> +{
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt) {
> + __be64 rpdu = cpu_to_be64(pdu);
> +
> + __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
> + sizeof(rpdu), &rpdu);
> + }
> +}
> +
> +static void blk_add_trace_unplug_timer(struct request_queue *q, unsigned int pdu)
> +{
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt) {
> + __be64 rpdu = cpu_to_be64(pdu);
> +
> + __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
> + sizeof(rpdu), &rpdu);
> + }
> +}
> +
> +static void blk_add_trace_split(struct request_queue *q, struct bio *bio,
> + unsigned int pdu)
> +{
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (bt) {
> + __be64 rpdu = cpu_to_be64(pdu);
> +
> + __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
> + BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
> + 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 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.device_from = cpu_to_be32(bio->bi_bdev->bd_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);
> +}
> +
> +/**
> + * blk_add_driver_data - Add binary message with driver-specific data
> + * @q: queue the io is for
> + * @rq: io request
> + * @data: driver-specific data
> + * @len: length of driver-specific data
> + *
> + * Description:
> + * Some drivers might want to write driver-specific data per request.
> + *
> + **/
> +void blk_add_driver_data(struct request_queue *q,
> + struct request *rq,
> + void *data, size_t len)
> +{
> + struct blk_trace *bt = q->blk_trace;
> +
> + if (likely(!bt))
> + return;
> +
> + if (blk_pc_request(rq))
> + __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
> + rq->errors, len, data);
> + else
> + __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
> + 0, BLK_TA_DRV_DATA, rq->errors, len, data);
> +}
> +EXPORT_SYMBOL_GPL(blk_add_driver_data);
> +
> +static int blk_register_tracepoints(void)
> +{
> + int ret;
> +
> + ret = register_trace_block_rq_abort(blk_add_trace_rq_abort);
> + WARN_ON(ret);
> + ret = register_trace_block_rq_insert(blk_add_trace_rq_insert);
> + WARN_ON(ret);
> + ret = register_trace_block_rq_issue(blk_add_trace_rq_issue);
> + WARN_ON(ret);
> + ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue);
> + WARN_ON(ret);
> + ret = register_trace_block_rq_complete(blk_add_trace_rq_complete);
> + WARN_ON(ret);
> + ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce);
> + WARN_ON(ret);
> + ret = register_trace_block_bio_complete(blk_add_trace_bio_complete);
> + WARN_ON(ret);
> + ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
> + WARN_ON(ret);
> + ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
> + WARN_ON(ret);
> + ret = register_trace_block_bio_queue(blk_add_trace_bio_queue);
> + WARN_ON(ret);
> + ret = register_trace_block_getrq(blk_add_trace_getrq);
> + WARN_ON(ret);
> + ret = register_trace_block_sleeprq(blk_add_trace_sleeprq);
> + WARN_ON(ret);
> + ret = register_trace_block_plug(blk_add_trace_plug);
> + WARN_ON(ret);
> + ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer);
> + WARN_ON(ret);
> + ret = register_trace_block_unplug_io(blk_add_trace_unplug_io);
> + WARN_ON(ret);
> + ret = register_trace_block_split(blk_add_trace_split);
> + WARN_ON(ret);
> + ret = register_trace_block_remap(blk_add_trace_remap);
> + WARN_ON(ret);
> + return 0;
> +}
> +
> +static void blk_unregister_tracepoints(void)
> +{
> + unregister_trace_block_remap(blk_add_trace_remap);
> + unregister_trace_block_split(blk_add_trace_split);
> + unregister_trace_block_unplug_io(blk_add_trace_unplug_io);
> + unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer);
> + unregister_trace_block_plug(blk_add_trace_plug);
> + unregister_trace_block_sleeprq(blk_add_trace_sleeprq);
> + unregister_trace_block_getrq(blk_add_trace_getrq);
> + unregister_trace_block_bio_queue(blk_add_trace_bio_queue);
> + unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge);
> + unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge);
> + unregister_trace_block_bio_complete(blk_add_trace_bio_complete);
> + unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce);
> + unregister_trace_block_rq_complete(blk_add_trace_rq_complete);
> + unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue);
> + unregister_trace_block_rq_issue(blk_add_trace_rq_issue);
> + unregister_trace_block_rq_insert(blk_add_trace_rq_insert);
> + unregister_trace_block_rq_insert(blk_add_trace_rq_abort);
> +
> + tracepoint_synchronize_unregister();
> +}
> diff --git a/block/elevator.c b/block/elevator.c
> index 59173a6..e83a1a4 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -33,6 +33,7 @@
> #include <linux/compiler.h>
> #include <linux/delay.h>
> #include <linux/blktrace_api.h>
> +#include <trace/block.h>
> #include <linux/hash.h>
> #include <linux/uaccess.h>
>
> @@ -586,7 +587,7 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
> unsigned ordseq;
> int unplug_it = 1;
>
> - blk_add_trace_rq(q, rq, BLK_TA_INSERT);
> + trace_block_rq_insert(q, rq);
>
> rq->q = q;
>
> @@ -772,7 +773,7 @@ struct request *elv_next_request(struct request_queue *q)
> * not be passed by new incoming requests
> */
> rq->cmd_flags |= REQ_STARTED;
> - blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
> + trace_block_rq_issue(q, rq);
>
> /*
> * We are now handing the request to the hardware,
> @@ -921,7 +922,7 @@ void elv_abort_queue(struct request_queue *q)
> while (!list_empty(&q->queue_head)) {
> rq = list_entry_rq(q->queue_head.next);
> rq->cmd_flags |= REQ_QUIET;
> - blk_add_trace_rq(q, rq, BLK_TA_ABORT);
> + trace_block_rq_abort(q, rq);
> __blk_end_request(rq, -EIO, blk_rq_bytes(rq));
> }
> }
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 6963ad1..f5e79b4 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -21,6 +21,7 @@
> #include <linux/idr.h>
> #include <linux/hdreg.h>
> #include <linux/blktrace_api.h>
> +#include <trace/block.h>
>
> #define DM_MSG_PREFIX "core"
>
> @@ -504,8 +505,7 @@ static void dec_pending(struct dm_io *io, int error)
> wake_up(&io->md->wait);
>
> if (io->error != DM_ENDIO_REQUEUE) {
> - blk_add_trace_bio(io->md->queue, io->bio,
> - BLK_TA_COMPLETE);
> + trace_block_bio_complete(io->md->queue, io->bio);
>
> bio_endio(io->bio, io->error);
> }
> @@ -598,7 +598,7 @@ static void __map_bio(struct dm_target *ti, struct bio *clone,
> if (r == DM_MAPIO_REMAPPED) {
> /* the bio has been remapped so dispatch it */
>
> - blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone,
> + trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
> tio->io->bio->bi_bdev->bd_dev,
> clone->bi_sector, sector);
>
> diff --git a/fs/bio.c b/fs/bio.c
> index 77a55bc..060859c 100644
> --- a/fs/bio.c
> +++ b/fs/bio.c
> @@ -26,6 +26,7 @@
> #include <linux/mempool.h>
> #include <linux/workqueue.h>
> #include <linux/blktrace_api.h>
> +#include <trace/block.h>
> #include <scsi/sg.h> /* for struct sg_iovec */
>
> static struct kmem_cache *bio_slab __read_mostly;
> @@ -1263,7 +1264,7 @@ struct bio_pair *bio_split(struct bio *bi, int first_sectors)
> if (!bp)
> return bp;
>
> - blk_add_trace_pdu_int(bdev_get_queue(bi->bi_bdev), BLK_TA_SPLIT, bi,
> + trace_block_split(bdev_get_queue(bi->bi_bdev), bi,
> bi->bi_sector + first_sectors);
>
> BUG_ON(bi->bi_vcnt != 1);
> diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
> index bdf505d..1dba349 100644
> --- a/include/linux/blktrace_api.h
> +++ b/include/linux/blktrace_api.h
> @@ -160,7 +160,6 @@ struct blk_trace {
>
> extern int blk_trace_ioctl(struct block_device *, unsigned, char __user *);
> extern void blk_trace_shutdown(struct request_queue *);
> -extern void __blk_add_trace(struct blk_trace *, sector_t, int, int, u32, int, int, void *);
> extern int do_blk_trace_setup(struct request_queue *q,
> char *name, dev_t dev, struct blk_user_trace_setup *buts);
> extern void __trace_note_message(struct blk_trace *, const char *fmt, ...);
> @@ -186,168 +185,8 @@ extern void __trace_note_message(struct blk_trace *, const char *fmt, ...);
> } while (0)
> #define BLK_TN_MAX_MSG 128
>
> -/**
> - * 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->cmd_flags & 0x03;
> -
> - if (likely(!bt))
> - return;
> -
> - if (blk_discard_rq(rq))
> - rw |= (1 << BIO_RW_DISCARD);
> -
> - 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;
> - __be64 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.device_from = cpu_to_be32(bio->bi_bdev->bd_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);
> -}
> -
> -/**
> - * blk_add_driver_data - Add binary message with driver-specific data
> - * @q: queue the io is for
> - * @rq: io request
> - * @data: driver-specific data
> - * @len: length of driver-specific data
> - *
> - * Description:
> - * Some drivers might want to write driver-specific data per request.
> - *
> - **/
> -static inline void blk_add_driver_data(struct request_queue *q,
> - struct request *rq,
> - void *data, size_t len)
> -{
> - struct blk_trace *bt = q->blk_trace;
> -
> - if (likely(!bt))
> - return;
> -
> - if (blk_pc_request(rq))
> - __blk_add_trace(bt, 0, rq->data_len, 0, BLK_TA_DRV_DATA,
> - rq->errors, len, data);
> - else
> - __blk_add_trace(bt, rq->hard_sector, rq->hard_nr_sectors << 9,
> - 0, BLK_TA_DRV_DATA, rq->errors, len, data);
> -}
> -
> +extern void blk_add_driver_data(struct request_queue *q, struct request *rq,
> + void *data, size_t len);
> extern int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
> char __user *arg);
> extern int blk_trace_startstop(struct request_queue *q, int start);
> @@ -356,13 +195,8 @@ extern int blk_trace_remove(struct request_queue *q);
> #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)
> -#define blk_add_driver_data(q, rq, data, len) do {} while (0)
> #define do_blk_trace_setup(q, name, dev, buts) (-ENOTTY)
> +#define blk_add_driver_data(q, rq, data, len) do {} while (0)
> #define blk_trace_setup(q, name, dev, arg) (-ENOTTY)
> #define blk_trace_startstop(q, start) (-ENOTTY)
> #define blk_trace_remove(q) (-ENOTTY)
> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
> index c5bb39c..3c89de0 100644
> --- a/include/linux/tracepoint.h
> +++ b/include/linux/tracepoint.h
> @@ -134,4 +134,11 @@ static inline void tracepoint_synchronize_unregister(void)
> synchronize_sched();
> }
>
> +/*
> + * tracepoint_synchronize_unregister must be called between the last tracepoint
> + * probe unregistration and the end of module exit to make sure there is no
> + * caller executing a probe when it is freed.
> + */
> +#define tracepoint_synchronize_unregister() synchronize_sched()
> +
> #endif
> diff --git a/include/trace/block.h b/include/trace/block.h
> new file mode 100644
> index 0000000..da4918b
> --- /dev/null
> +++ b/include/trace/block.h
> @@ -0,0 +1,60 @@
> +#ifndef _TRACE_BLOCK_H
> +#define _TRACE_BLOCK_H
> +
> +#include <linux/blkdev.h>
> +#include <linux/tracepoint.h>
> +
> +DEFINE_TRACE(block_rq_abort,
> + TPPROTO(struct request_queue *q, struct request *rq),
> + TPARGS(q, rq));
> +DEFINE_TRACE(block_rq_insert,
> + TPPROTO(struct request_queue *q, struct request *rq),
> + TPARGS(q, rq));
> +DEFINE_TRACE(block_rq_issue,
> + TPPROTO(struct request_queue *q, struct request *rq),
> + TPARGS(q, rq));
> +DEFINE_TRACE(block_rq_requeue,
> + TPPROTO(struct request_queue *q, struct request *rq),
> + TPARGS(q, rq));
> +DEFINE_TRACE(block_rq_complete,
> + TPPROTO(struct request_queue *q, struct request *rq),
> + TPARGS(q, rq));
> +DEFINE_TRACE(block_bio_bounce,
> + TPPROTO(struct request_queue *q, struct bio *bio),
> + TPARGS(q, bio));
> +DEFINE_TRACE(block_bio_complete,
> + TPPROTO(struct request_queue *q, struct bio *bio),
> + TPARGS(q, bio));
> +DEFINE_TRACE(block_bio_backmerge,
> + TPPROTO(struct request_queue *q, struct bio *bio),
> + TPARGS(q, bio));
> +DEFINE_TRACE(block_bio_frontmerge,
> + TPPROTO(struct request_queue *q, struct bio *bio),
> + TPARGS(q, bio));
> +DEFINE_TRACE(block_bio_queue,
> + TPPROTO(struct request_queue *q, struct bio *bio),
> + TPARGS(q, bio));
> +DEFINE_TRACE(block_getrq,
> + TPPROTO(struct request_queue *q, struct bio *bio, int rw),
> + TPARGS(q, bio, rw));
> +DEFINE_TRACE(block_sleeprq,
> + TPPROTO(struct request_queue *q, struct bio *bio, int rw),
> + TPARGS(q, bio, rw));
> +DEFINE_TRACE(block_plug,
> + TPPROTO(struct request_queue *q),
> + TPARGS(q));
> +DEFINE_TRACE(block_unplug_timer,
> + TPPROTO(struct request_queue *q, unsigned int pdu),
> + TPARGS(q, pdu));
> +DEFINE_TRACE(block_unplug_io,
> + TPPROTO(struct request_queue *q, unsigned int pdu),
> + TPARGS(q, pdu));
> +DEFINE_TRACE(block_split,
> + TPPROTO(struct request_queue *q, struct bio *bio, unsigned int pdu),
> + TPARGS(q, bio, pdu));
> +DEFINE_TRACE(block_remap,
> + TPPROTO(struct request_queue *q, struct bio *bio, dev_t dev,
> + sector_t from, sector_t to),
> + TPARGS(q, bio, dev, from, to));
> +
> +#endif
> diff --git a/mm/bounce.c b/mm/bounce.c
> index 06722c4..bd1caaa 100644
> --- a/mm/bounce.c
> +++ b/mm/bounce.c
> @@ -14,6 +14,7 @@
> #include <linux/hash.h>
> #include <linux/highmem.h>
> #include <linux/blktrace_api.h>
> +#include <trace/block.h>
> #include <asm/tlbflush.h>
>
> #define POOL_SIZE 64
> @@ -222,7 +223,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
> if (!bio)
> return;
>
> - blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
> + trace_block_bio_bounce(q, *bio_orig);
>
> /*
> * at least one page was bounced, fill in possible non-highmem
>

--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68