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Commit 45ad21ca authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
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tracing: Have trace_array keep track if snapshot buffer is allocated 



The snapshot buffer belongs to the trace array not the tracer that is
running. The trace array should be the data structure that keeps track
of whether or not the snapshot buffer is allocated, not the tracer
desciptor. Having the trace array keep track of it makes modifications
so much easier.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 6de58e62

kernel/trace/trace.c

+15 −17
Original line number Diff line number Diff line
@@ -667,7 +667,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) 


	WARN_ON_ONCE(!irqs_disabled());



	if (!tr->current_trace->allocated_snapshot) {

	if (!tr->allocated_snapshot) {

		/* Only the nop tracer should hit this when disabling */

		WARN_ON_ONCE(tr->current_trace != &nop_trace);

		return;
@@ -700,7 +700,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) 
		return;



	WARN_ON_ONCE(!irqs_disabled());

	if (WARN_ON_ONCE(!tr->current_trace->allocated_snapshot))

	if (WARN_ON_ONCE(!tr->allocated_snapshot))

		return;



	arch_spin_lock(&ftrace_max_lock);
@@ -802,7 +802,7 @@ int register_tracer(struct tracer *type) 
			if (ring_buffer_expanded)

				ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,

						   RING_BUFFER_ALL_CPUS);

			type->allocated_snapshot = true;

			tr->allocated_snapshot = true;

		}

#endif
@@ -822,7 +822,7 @@ int register_tracer(struct tracer *type) 


#ifdef CONFIG_TRACER_MAX_TRACE

		if (type->use_max_tr) {

			type->allocated_snapshot = false;

			tr->allocated_snapshot = false;



			/* Shrink the max buffer again */

			if (ring_buffer_expanded)
@@ -2463,7 +2463,7 @@ static void show_snapshot_percpu_help(struct seq_file *m) 


static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)

{

	if (iter->trace->allocated_snapshot)

	if (iter->tr->allocated_snapshot)

		seq_printf(m, "#\n# * Snapshot is allocated *\n#\n");

	else

		seq_printf(m, "#\n# * Snapshot is freed *\n#\n");
@@ -3364,12 +3364,12 @@ static int tracing_set_tracer(const char *buf) 
	if (tr->current_trace->reset)

		tr->current_trace->reset(tr);



#ifdef CONFIG_TRACER_MAX_TRACE

	had_max_tr = tr->current_trace->allocated_snapshot;



	/* Current trace needs to be nop_trace before synchronize_sched */

	tr->current_trace = &nop_trace;



#ifdef CONFIG_TRACER_MAX_TRACE

	had_max_tr = tr->allocated_snapshot;



	if (had_max_tr && !t->use_max_tr) {

		/*

		 * We need to make sure that the update_max_tr sees that
@@ -3387,10 +3387,8 @@ static int tracing_set_tracer(const char *buf) 
		ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);

		set_buffer_entries(&tr->max_buffer, 1);

		tracing_reset_online_cpus(&tr->max_buffer);

		tr->current_trace->allocated_snapshot = false;

		tr->allocated_snapshot = false;

	}

#else

	tr->current_trace = &nop_trace;

#endif

	destroy_trace_option_files(topts);
@@ -3403,7 +3401,7 @@ static int tracing_set_tracer(const char *buf) 
						   RING_BUFFER_ALL_CPUS);

		if (ret < 0)

			goto out;

		t->allocated_snapshot = true;

		tr->allocated_snapshot = true;

	}

#endif
@@ -4275,13 +4273,13 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
			ret = -EINVAL;

			break;

		}

		if (tr->current_trace->allocated_snapshot) {

		if (tr->allocated_snapshot) {

			/* free spare buffer */

			ring_buffer_resize(tr->max_buffer.buffer, 1,

					   RING_BUFFER_ALL_CPUS);

			set_buffer_entries(&tr->max_buffer, 1);

			tracing_reset_online_cpus(&tr->max_buffer);

			tr->current_trace->allocated_snapshot = false;

			tr->allocated_snapshot = false;

		}

		break;

	case 1:
@@ -4292,13 +4290,13 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
			break;

		}

#endif

		if (!tr->current_trace->allocated_snapshot) {

		if (!tr->allocated_snapshot) {

			/* allocate spare buffer */

			ret = resize_buffer_duplicate_size(&tr->max_buffer,

					&tr->trace_buffer, RING_BUFFER_ALL_CPUS);

			if (ret < 0)

				break;

			tr->current_trace->allocated_snapshot = true;

			tr->allocated_snapshot = true;

		}

		local_irq_disable();

		/* Now, we're going to swap */
@@ -4309,7 +4307,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
		local_irq_enable();

		break;

	default:

		if (tr->current_trace->allocated_snapshot) {

		if (tr->allocated_snapshot) {

			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)

				tracing_reset_online_cpus(&tr->max_buffer);

			else

kernel/trace/trace.h

+1 −1
Original line number Diff line number Diff line
@@ -197,6 +197,7 @@ struct trace_array { 
	 * the trace_buffer so the tracing can continue.

	 */

	struct trace_buffer	max_buffer;

	bool			allocated_snapshot;

#endif

	int			buffer_disabled;

	struct trace_cpu	trace_cpu;	/* place holder */
@@ -367,7 +368,6 @@ struct tracer { 
	bool			enabled;

#ifdef CONFIG_TRACER_MAX_TRACE

	bool			use_max_tr;

	bool			allocated_snapshot;

#endif

};