Merge branch 'tip/perf/core' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core

kernel/trace/ring_buffer.c

@@ -443,6 +443,7 @@ int ring_buffer_print_page_header(struct trace_seq *s)
  */
 struct ring_buffer_per_cpu {
 	int				cpu;
+	atomic_t			record_disabled;
 	struct ring_buffer		*buffer;
 	spinlock_t			reader_lock;	/* serialize readers */
 	arch_spinlock_t			lock;
@@ -462,7 +463,6 @@ struct ring_buffer_per_cpu {
 	unsigned long			read;
 	u64				write_stamp;
 	u64				read_stamp;
-	atomic_t			record_disabled;
 };
 
 struct ring_buffer {

kernel/trace/trace.c

@@ -344,7 +344,7 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
 /* trace_flags holds trace_options default values */
 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
 	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
-	TRACE_ITER_GRAPH_TIME;
+	TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD;
 
 static int trace_stop_count;
 static DEFINE_SPINLOCK(tracing_start_lock);
@@ -428,6 +428,7 @@ static const char *trace_options[] = {
 	"latency-format",
 	"sleep-time",
 	"graph-time",
+	"record-cmd",
 	NULL
 };
 
@@ -659,6 +660,10 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
+	if (!current_trace->use_max_tr) {
+		WARN_ON_ONCE(1);
+		return;
+	}
 	arch_spin_lock(&ftrace_max_lock);
 
 	tr->buffer = max_tr.buffer;
@@ -685,6 +690,11 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 		return;
 
 	WARN_ON_ONCE(!irqs_disabled());
+	if (!current_trace->use_max_tr) {
+		WARN_ON_ONCE(1);
+		return;
+	}
+
 	arch_spin_lock(&ftrace_max_lock);
 
 	ftrace_disable_cpu();
@@ -729,7 +739,7 @@ __acquires(kernel_lock)
 		return -1;
 	}
 
-	if (strlen(type->name) > MAX_TRACER_SIZE) {
+	if (strlen(type->name) >= MAX_TRACER_SIZE) {
 		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
 		return -1;
 	}
@@ -2508,6 +2518,9 @@ static void set_tracer_flags(unsigned int mask, int enabled)
 		trace_flags |= mask;
 	else
 		trace_flags &= ~mask;
+
+	if (mask == TRACE_ITER_RECORD_CMD)
+		trace_event_enable_cmd_record(enabled);
 }
 
 static ssize_t
@@ -2746,6 +2759,9 @@ static int tracing_resize_ring_buffer(unsigned long size)
 	if (ret < 0)
 		return ret;
 
+	if (!current_trace->use_max_tr)
+		goto out;
+
 	ret = ring_buffer_resize(max_tr.buffer, size);
 	if (ret < 0) {
 		int r;
@@ -2773,11 +2789,14 @@ static int tracing_resize_ring_buffer(unsigned long size)
 		return ret;
 	}
 
+	max_tr.entries = size;
+ out:
 	global_trace.entries = size;
 
 	return ret;
 }
 
+
 /**
  * tracing_update_buffers - used by tracing facility to expand ring buffers
  *
@@ -2838,12 +2857,26 @@ static int tracing_set_tracer(const char *buf)
 	trace_branch_disable();
 	if (current_trace && current_trace->reset)
 		current_trace->reset(tr);
-
+	if (current_trace && current_trace->use_max_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(max_tr.buffer, 1);
+		max_tr.entries = 1;
+	}
 	destroy_trace_option_files(topts);
 
 	current_trace = t;
 
 	topts = create_trace_option_files(current_trace);
+	if (current_trace->use_max_tr) {
+		ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
+		if (ret < 0)
+			goto out;
+		max_tr.entries = global_trace.entries;
+	}
 
 	if (t->init) {
 		ret = tracer_init(t, tr);
@@ -3426,7 +3459,6 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
 	}
 
 	tracing_start();
-	max_tr.entries = global_trace.entries;
 	mutex_unlock(&trace_types_lock);
 
 	return cnt;
@@ -4531,16 +4563,14 @@ __init static int tracer_alloc_buffers(void)
 
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-	max_tr.buffer = ring_buffer_alloc(ring_buf_size,
-					     TRACE_BUFFER_FLAGS);
+	max_tr.buffer = ring_buffer_alloc(1, TRACE_BUFFER_FLAGS);
 	if (!max_tr.buffer) {
 		printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
 		WARN_ON(1);
 		ring_buffer_free(global_trace.buffer);
 		goto out_free_cpumask;
 	}
-	max_tr.entries = ring_buffer_size(max_tr.buffer);
-	WARN_ON(max_tr.entries != global_trace.entries);
+	max_tr.entries = 1;
 #endif
 
 	/* Allocate the first page for all buffers */

kernel/trace/trace.h

@@ -274,6 +274,7 @@ struct tracer {
 	struct tracer		*next;
 	int			print_max;
 	struct tracer_flags	*flags;
+	int			use_max_tr;
 };
 
 
@@ -581,6 +582,7 @@ enum trace_iterator_flags {
 	TRACE_ITER_LATENCY_FMT		= 0x20000,
 	TRACE_ITER_SLEEP_TIME		= 0x40000,
 	TRACE_ITER_GRAPH_TIME		= 0x80000,
+	TRACE_ITER_RECORD_CMD		= 0x100000,
 };
 
 /*
@@ -713,6 +715,8 @@ filter_check_discard(struct ftrace_event_call *call, void *rec,
 	return 0;
 }
 
+extern void trace_event_enable_cmd_record(bool enable);
+
 extern struct mutex event_mutex;
 extern struct list_head ftrace_events;
 

kernel/trace/trace_events.c

@@ -170,6 +170,26 @@ int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
 }
 EXPORT_SYMBOL_GPL(ftrace_event_reg);
 
+void trace_event_enable_cmd_record(bool enable)
+{
+	struct ftrace_event_call *call;
+
+	mutex_lock(&event_mutex);
+	list_for_each_entry(call, &ftrace_events, list) {
+		if (!(call->flags & TRACE_EVENT_FL_ENABLED))
+			continue;
+
+		if (enable) {
+			tracing_start_cmdline_record();
+			call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
+		} else {
+			tracing_stop_cmdline_record();
+			call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
+		}
+	}
+	mutex_unlock(&event_mutex);
+}
+
 static int ftrace_event_enable_disable(struct ftrace_event_call *call,
 					int enable)
 {
@@ -179,13 +199,19 @@ static int ftrace_event_enable_disable(struct ftrace_event_call *call,
 	case 0:
 		if (call->flags & TRACE_EVENT_FL_ENABLED) {
 			call->flags &= ~TRACE_EVENT_FL_ENABLED;
-			tracing_stop_cmdline_record();
+			if (call->flags & TRACE_EVENT_FL_RECORDED_CMD) {
+				tracing_stop_cmdline_record();
+				call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
+			}
 			call->class->reg(call, TRACE_REG_UNREGISTER);
 		}
 		break;
 	case 1:
 		if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
-			tracing_start_cmdline_record();
+			if (trace_flags & TRACE_ITER_RECORD_CMD) {
+				tracing_start_cmdline_record();
+				call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
+			}
 			ret = call->class->reg(call, TRACE_REG_REGISTER);
 			if (ret) {
 				tracing_stop_cmdline_record();

kernel/trace/trace_irqsoff.c

@@ -649,6 +649,7 @@ static struct tracer irqsoff_tracer __read_mostly =
 #endif
 	.open           = irqsoff_trace_open,
 	.close          = irqsoff_trace_close,
+	.use_max_tr	= 1,
 };
 # define register_irqsoff(trace) register_tracer(&trace)
 #else
@@ -681,6 +682,7 @@ static struct tracer preemptoff_tracer __read_mostly =
 #endif
 	.open		= irqsoff_trace_open,
 	.close		= irqsoff_trace_close,
+	.use_max_tr	= 1,
 };
 # define register_preemptoff(trace) register_tracer(&trace)
 #else
@@ -715,6 +717,7 @@ static struct tracer preemptirqsoff_tracer __read_mostly =
 #endif
 	.open		= irqsoff_trace_open,
 	.close		= irqsoff_trace_close,
+	.use_max_tr	= 1,
 };
 
 # define register_preemptirqsoff(trace) register_tracer(&trace)

kernel/trace/trace_output.c

@@ -16,9 +16,6 @@
 
 DECLARE_RWSEM(trace_event_mutex);
 
-DEFINE_PER_CPU(struct trace_seq, ftrace_event_seq);
-EXPORT_PER_CPU_SYMBOL(ftrace_event_seq);
-
 static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
 
 static int next_event_type = __TRACE_LAST_TYPE + 1;

kernel/trace/trace_sched_wakeup.c

@@ -382,6 +382,7 @@ static struct tracer wakeup_tracer __read_mostly =
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest    = trace_selftest_startup_wakeup,
 #endif
+	.use_max_tr	= 1,
 };
 
 static struct tracer wakeup_rt_tracer __read_mostly =
@@ -396,6 +397,7 @@ static struct tracer wakeup_rt_tracer __read_mostly =
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest    = trace_selftest_startup_wakeup,
 #endif
+	.use_max_tr	= 1,
 };
 
 __init static int init_wakeup_tracer(void)