Commit 18cea459 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

blktrace: print out BLK_TN_MESSAGE properly 



Impact: improve ftrace plugin output

Before this patch:

 # cat trace
         make-5383  [001]   741.240059:   8,7    P   N [make]
 __trace_note_message: cfq1074

 # echo 1 > options/blk_classic
 # cat trace
   8,7    1     0.692221252     0  C   W 130411392 + 1024 [0]
 Bad pc action 6361
 Bad pc action 283d

 # echo 0 > options/blk_classic
 # echo bin > trace_options
 # cat trace_pipe | blkparse -i -
 (can't parse messages generated by blk_add_trace_msg())

After this patch:
 # cat trace
      <idle>-0     [001]   187.600933:   8,7    C   W 145220224 + 8 [0]
      <idle>-0     [001]   187.600946:   8,7    m   N cfq1076 complete

 # echo 1 > options/blk_classic
 # cat trace
   8,7    1     0.256378996   238  I   W 113190728 + 8 [pdflush]
   8,7    1     0.256378998   238  m   N cfq1076 insert_request

 # echo 0 > options/blk_classic
 # echo bin > trace_options
 # cat trace_pipe | blkparse -i -
  8,7    1        0    22.973250293     0  C   W 102770576 + 8 [0]
  8,7    1        0    22.973259213     0  m   N cfq1076 complete

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarJens Axboe <jens.axboe@oracle.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b6a4b0c3

kernel/trace/blktrace.c

+61 −19
Original line number Diff line number Diff line
@@ -59,22 +59,39 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action, 
		       const void *data, size_t len)

{

	struct blk_io_trace *t;

	struct ring_buffer_event *event = NULL;

	int pc = 0;

	int cpu = smp_processor_id();

	bool blk_tracer = blk_tracer_enabled;



	if (blk_tracer) {

		pc = preempt_count();

		event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,

						  sizeof(*t) + len,

						  0, pc);

		if (!event)

			return;

		t = ring_buffer_event_data(event);

		goto record_it;

	}



	if (!bt->rchan)

		return;



	t = relay_reserve(bt->rchan, sizeof(*t) + len);

	if (t) {

		const int cpu = smp_processor_id();



		t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;

		t->time = ktime_to_ns(ktime_get());

record_it:

		t->device = bt->dev;

		t->action = action;

		t->pid = pid;

		t->cpu = cpu;

		t->pdu_len = len;

		memcpy((void *) t + sizeof(*t), data, len);



		if (blk_tracer)

			trace_buffer_unlock_commit(blk_tr, event, 0, pc);

	}

}
@@ -110,14 +127,8 @@ void __trace_note_message(struct blk_trace *bt, const char *fmt, ...) 
	unsigned long flags;

	char *buf;



	if (blk_tracer_enabled) {

		va_start(args, fmt);

		ftrace_vprintk(fmt, args);

		va_end(args);

		return;

	}



	if (!bt->msg_data)

	if (unlikely(bt->trace_state != Blktrace_running &&

		     !blk_tracer_enabled))

		return;



	local_irq_save(flags);
@@ -168,9 +179,9 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 
	unsigned long *sequence;

	pid_t pid;

	int cpu, pc = 0;

	bool blk_tracer = blk_tracer_enabled;



	if (unlikely(bt->trace_state != Blktrace_running &&

		     !blk_tracer_enabled))

	if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))

		return;



	what |= ddir_act[rw & WRITE];
@@ -185,7 +196,7 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes, 
		return;

	cpu = raw_smp_processor_id();



	if (blk_tracer_enabled) {

	if (blk_tracer) {

		tracing_record_cmdline(current);



		pc = preempt_count();
@@ -235,7 +246,7 @@ record_it: 
		if (pdu_len)

			memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);



		if (blk_tracer_enabled) {

		if (blk_tracer) {

			trace_buffer_unlock_commit(blk_tr, event, 0, pc);

			return;

		}
@@ -922,6 +933,11 @@ static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 
	int i = 0;

	int tc = t->action >> BLK_TC_SHIFT;



	if (t->action == BLK_TN_MESSAGE) {

		rwbs[i++] = 'N';

		goto out;

	}



	if (tc & BLK_TC_DISCARD)

		rwbs[i++] = 'D';

	else if (tc & BLK_TC_WRITE)
@@ -939,7 +955,7 @@ static void fill_rwbs(char *rwbs, const struct blk_io_trace *t) 
		rwbs[i++] = 'S';

	if (tc & BLK_TC_META)

		rwbs[i++] = 'M';



out:

	rwbs[i] = '\0';

}
@@ -1074,6 +1090,17 @@ static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent) 
				get_pdu_int(ent), cmd);

}



static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)

{

	int ret;

	const struct blk_io_trace *t = te_blk_io_trace(ent);



	ret = trace_seq_putmem(s, t + 1, t->pdu_len);

	if (ret)

		return trace_seq_putc(s, '\n');

	return ret;

}



/*

 * struct tracer operations

 */
@@ -1146,6 +1173,13 @@ static enum print_line_t print_one_line(struct trace_iterator *iter, 
	long_act   = !!(trace_flags & TRACE_ITER_VERBOSE);

	log_action = classic ? &blk_log_action_classic : &blk_log_action;



	if (t->action == BLK_TN_MESSAGE) {

		ret = log_action(iter, long_act ? "message" : "m");

		if (ret)

			ret = blk_log_msg(s, iter->ent);

		goto out;

	}



	if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))

		ret = trace_seq_printf(s, "Bad pc action %x\n", what);

	else {
@@ -1153,7 +1187,7 @@ static enum print_line_t print_one_line(struct trace_iterator *iter, 
		if (ret)

			ret = what2act[what].print(s, iter->ent);

	}



out:

	return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;

}
@@ -1253,11 +1287,16 @@ static int blk_trace_remove_queue(struct request_queue *q) 
static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)

{

	struct blk_trace *old_bt, *bt = NULL;

	int ret = -ENOMEM;



	bt = kzalloc(sizeof(*bt), GFP_KERNEL);

	if (!bt)

		return -ENOMEM;



	bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));

	if (!bt->msg_data)

		goto free_bt;



	bt->dev = dev;

	bt->act_mask = (u16)-1;

	bt->end_lba = -1ULL;
@@ -1265,14 +1304,17 @@ static int blk_trace_setup_queue(struct request_queue *q, dev_t dev) 
	old_bt = xchg(&q->blk_trace, bt);

	if (old_bt != NULL) {

		(void)xchg(&q->blk_trace, old_bt);

		kfree(bt);

		return -EBUSY;

		ret = -EBUSY;

		goto free_bt;

	}



	if (atomic_inc_return(&blk_probes_ref) == 1)

		blk_register_tracepoints();



	return 0;



free_bt:

	blk_trace_free(bt);

	return ret;

}



/*

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