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Commit 7bbc67fb authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'tracing-fixes-for-linus' of... 

Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  ftrace: prevent recursion
  tracing, doc: update mmiotrace documentation
  x86, mmiotrace: fix buffer overrun detection
  function tracing: fix wrong position computing of stack_trace
parents 66a45cc4 4f5a7f40

Documentation/tracers/mmiotrace.txt

+4 −2
Original line number Diff line number Diff line
@@ -37,7 +37,7 @@ $ echo mmiotrace > /debug/tracing/current_tracer 
$ cat /debug/tracing/trace_pipe > mydump.txt &

Start X or whatever.

$ echo "X is up" > /debug/tracing/trace_marker

$ echo none > /debug/tracing/current_tracer

$ echo nop > /debug/tracing/current_tracer

Check for lost events.
@@ -66,7 +66,7 @@ which action. It is recommended to place descriptive markers about what you 
do.



Shut down mmiotrace (requires root privileges):

$ echo none > /debug/tracing/current_tracer

$ echo nop > /debug/tracing/current_tracer

The 'cat' process exits. If it does not, kill it by issuing 'fg' command and

pressing ctrl+c.
@@ -81,7 +81,9 @@ are: 
$ cat /debug/tracing/trace_entries

gives you a number. Approximately double this number and write it back, for

instance:

$ echo 0 > /debug/tracing/tracing_enabled

$ echo 128000 > /debug/tracing/trace_entries

$ echo 1 > /debug/tracing/tracing_enabled

Then start again from the top.



If you are doing a trace for a driver project, e.g. Nouveau, you should also

kernel/trace/ring_buffer.c

+1 −1
Original line number Diff line number Diff line
@@ -1215,7 +1215,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, 


 out:

	if (resched)

		preempt_enable_notrace();

		preempt_enable_no_resched_notrace();

	else

		preempt_enable_notrace();

	return NULL;

kernel/trace/trace_mmiotrace.c

+7 −9
Original line number Diff line number Diff line
@@ -18,12 +18,14 @@ struct header_iter { 


static struct trace_array *mmio_trace_array;

static bool overrun_detected;

static unsigned long prev_overruns;



static void mmio_reset_data(struct trace_array *tr)

{

	int cpu;



	overrun_detected = false;

	prev_overruns = 0;

	tr->time_start = ftrace_now(tr->cpu);



	for_each_online_cpu(cpu)
@@ -128,16 +130,12 @@ static void mmio_close(struct trace_iterator *iter) 


static unsigned long count_overruns(struct trace_iterator *iter)

{

	int cpu;

	unsigned long cnt = 0;

/* FIXME: */

#if 0

	for_each_online_cpu(cpu) {

		cnt += iter->overrun[cpu];

		iter->overrun[cpu] = 0;

	}

#endif

	(void)cpu;

	unsigned long over = ring_buffer_overruns(iter->tr->buffer);



	if (over > prev_overruns)

		cnt = over - prev_overruns;

	prev_overruns = over;

	return cnt;

}

kernel/trace/trace_stack.c

+15 −9
Original line number Diff line number Diff line
@@ -184,11 +184,16 @@ static struct file_operations stack_max_size_fops = { 
static void *

t_next(struct seq_file *m, void *v, loff_t *pos)

{

	long i = (long)m->private;

	long i;



	(*pos)++;



	if (v == SEQ_START_TOKEN)

		i = 0;

	else {

		i = *(long *)v;

		i++;

	}



	if (i >= max_stack_trace.nr_entries ||

	    stack_dump_trace[i] == ULONG_MAX)
@@ -201,12 +206,15 @@ t_next(struct seq_file *m, void *v, loff_t *pos) 


static void *t_start(struct seq_file *m, loff_t *pos)

{

	void *t = &m->private;

	void *t = SEQ_START_TOKEN;

	loff_t l = 0;



	local_irq_disable();

	__raw_spin_lock(&max_stack_lock);



	if (*pos == 0)

		return SEQ_START_TOKEN;



	for (; t && l < *pos; t = t_next(m, t, &l))

		;
@@ -235,10 +243,10 @@ static int trace_lookup_stack(struct seq_file *m, long i) 


static int t_show(struct seq_file *m, void *v)

{

	long i = *(long *)v;

	long i;

	int size;



	if (i < 0) {

	if (v == SEQ_START_TOKEN) {

		seq_printf(m, "        Depth   Size      Location"

			   "    (%d entries)\n"

			   "        -----   ----      --------\n",
@@ -246,6 +254,8 @@ static int t_show(struct seq_file *m, void *v) 
		return 0;

	}



	i = *(long *)v;



	if (i >= max_stack_trace.nr_entries ||

	    stack_dump_trace[i] == ULONG_MAX)

		return 0;
@@ -275,10 +285,6 @@ static int stack_trace_open(struct inode *inode, struct file *file) 
	int ret;



	ret = seq_open(file, &stack_trace_seq_ops);

	if (!ret) {

		struct seq_file *m = file->private_data;

		m->private = (void *)-1;

	}



	return ret;

}