Commit 3209cff4 authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
Browse files

tracing: Add alloc/free_snapshot() to replace duplicate code 



Add alloc_snapshot() and free_snapshot() to allocate and free the
snapshot buffer respectively, and use these to remove duplicate
code.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent e1df4cb6

kernel/trace/trace.c

+42 −37
Original line number Diff line number Diff line
@@ -149,14 +149,14 @@ static int __init set_ftrace_dump_on_oops(char *str) 
}

__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);



static int __init alloc_snapshot(char *str)

static int __init boot_alloc_snapshot(char *str)

{

	allocate_snapshot = true;

	/* We also need the main ring buffer expanded */

	ring_buffer_expanded = true;

	return 1;

}

__setup("alloc_snapshot", alloc_snapshot);

__setup("alloc_snapshot", boot_alloc_snapshot);





static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
@@ -470,6 +470,38 @@ EXPORT_SYMBOL_GPL(tracing_snapshot); 


static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,

					struct trace_buffer *size_buf, int cpu_id);

static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);



static int alloc_snapshot(struct trace_array *tr)

{

	int ret;



	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)

			return ret;



		tr->allocated_snapshot = true;

	}



	return 0;

}



void free_snapshot(struct trace_array *tr)

{

	/*

	 * We don't free the ring buffer. instead, resize it because

	 * The max_tr ring buffer has some state (e.g. ring->clock) and

	 * we want preserve it.

	 */

	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->allocated_snapshot = false;

}



/**

 * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
@@ -487,17 +519,10 @@ void tracing_snapshot_alloc(void) 
	struct trace_array *tr = &global_trace;

	int ret;



	if (!tr->allocated_snapshot) {



		/* allocate spare buffer */

		ret = resize_buffer_duplicate_size(&tr->max_buffer,

				   &tr->trace_buffer, RING_BUFFER_ALL_CPUS);

	ret = alloc_snapshot(tr);

	if (WARN_ON(ret < 0))

		return;



		tr->allocated_snapshot = true;

	}



	tracing_snapshot();

}

EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
@@ -3581,15 +3606,7 @@ static int tracing_set_tracer(const char *buf) 
		 * so a synchronized_sched() is sufficient.

		 */

		synchronize_sched();

		/*

		 * We don't free the ring buffer. instead, resize it because

		 * The max_tr ring buffer has some state (e.g. ring->clock) and

		 * we want preserve it.

		 */

		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->allocated_snapshot = false;

		free_snapshot(tr);

	}

#endif

	destroy_trace_option_files(topts);
@@ -3598,12 +3615,9 @@ static int tracing_set_tracer(const char *buf) 


#ifdef CONFIG_TRACER_MAX_TRACE

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

		/* we need to make per cpu buffer sizes equivalent */

		ret = resize_buffer_duplicate_size(&tr->max_buffer, &tr->trace_buffer,

						   RING_BUFFER_ALL_CPUS);

		ret = alloc_snapshot(tr);

		if (ret < 0)

			goto out;

		tr->allocated_snapshot = true;

	}

#endif
@@ -4475,14 +4489,8 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
			ret = -EINVAL;

			break;

		}

		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->allocated_snapshot = false;

		}

		if (tr->allocated_snapshot)

			free_snapshot(tr);

		break;

	case 1:

/* Only allow per-cpu swap if the ring buffer supports it */
@@ -4493,12 +4501,9 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, 
		}

#endif

		if (!tr->allocated_snapshot) {

			/* allocate spare buffer */

			ret = resize_buffer_duplicate_size(&tr->max_buffer,

					&tr->trace_buffer, RING_BUFFER_ALL_CPUS);

			ret = alloc_snapshot(tr);

			if (ret < 0)

				break;

			tr->allocated_snapshot = true;

		}

		local_irq_disable();

		/* Now, we're going to swap */