From 7be421510b91491d5aa5a29fa1005712039b95af Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Thu, 5 Feb 2009 01:13:37 -0500
Subject: trace: Remove unused trace_array_cpu parameter

Impact: cleanup

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/trace/trace_sched_switch.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index df175cb4564..c4f9add5ec9 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -43,7 +43,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 	data = ctx_trace->data[cpu];
 
 	if (likely(!atomic_read(&data->disabled)))
-		tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
+		tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc);
 
 	local_irq_restore(flags);
 }
@@ -66,7 +66,7 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 	data = ctx_trace->data[cpu];
 
 	if (likely(!atomic_read(&data->disabled)))
-		tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
+		tracing_sched_wakeup_trace(ctx_trace, wakee, current,
 					   flags, pc);
 
 	local_irq_restore(flags);
-- 
cgit v1.2.3-70-g09d2


From b6f11df26fdc28324cf9c9e3b77f2dc985c1bb13 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Thu, 5 Feb 2009 18:02:00 -0200
Subject: trace: Call tracing_reset_online_cpus before tracer->init()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Impact: cleanup

To make it easy for ftrace plugin writers, as this was open coded in
the existing plugins

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 block/blktrace.c                     |  2 --
 kernel/trace/trace.c                 |  8 +++++++-
 kernel/trace/trace.h                 |  1 +
 kernel/trace/trace_branch.c          |  1 -
 kernel/trace/trace_functions.c       | 17 +++--------------
 kernel/trace/trace_functions_graph.c |  1 -
 kernel/trace/trace_hw_branches.c     |  1 -
 kernel/trace/trace_nop.c             |  1 -
 kernel/trace/trace_sched_switch.c    |  8 +-------
 kernel/trace/trace_selftest.c        | 18 +++++++++---------
 kernel/trace/trace_sysprof.c         | 14 ++++----------
 11 files changed, 25 insertions(+), 47 deletions(-)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/block/blktrace.c b/block/blktrace.c
index 834cd84037b..ca6d32061e4 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -1086,8 +1086,6 @@ static void blk_tracer_print_header(struct seq_file *m)
 
 static void blk_tracer_start(struct trace_array *tr)
 {
-	tracing_reset_online_cpus(tr);
-
 	mutex_lock(&blk_probe_mutex);
 	if (atomic_add_return(1, &blk_probes_ref) == 1)
 		if (blk_register_tracepoints())
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8fad3776e84..ef4dbac9556 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2171,6 +2171,12 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 
+int tracer_init(struct tracer *t, struct trace_array *tr)
+{
+	tracing_reset_online_cpus(tr);
+	return t->init(tr);
+}
+
 static int tracing_set_tracer(const char *buf)
 {
 	struct trace_array *tr = &global_trace;
@@ -2195,7 +2201,7 @@ static int tracing_set_tracer(const char *buf)
 
 	current_trace = t;
 	if (t->init) {
-		ret = t->init(tr);
+		ret = tracer_init(t, tr);
 		if (ret)
 			goto out;
 	}
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e03f157c772..f2742fb1575 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -395,6 +395,7 @@ struct trace_iterator {
 	cpumask_var_t		started;
 };
 
+int tracer_init(struct tracer *t, struct trace_array *tr);
 int tracing_is_enabled(void);
 void trace_wake_up(void);
 void tracing_reset(struct trace_array *tr, int cpu);
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 48b2196abe3..f8ae2c50e01 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -131,7 +131,6 @@ static void stop_branch_trace(struct trace_array *tr)
 
 static int branch_trace_init(struct trace_array *tr)
 {
-	tracing_reset_online_cpus(tr);
 	start_branch_trace(tr);
 	return 0;
 }
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index d067cea2ccc..36bf9568ccd 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -24,32 +24,21 @@ static struct trace_array	*func_trace;
 static void tracing_start_function_trace(void);
 static void tracing_stop_function_trace(void);
 
-static void start_function_trace(struct trace_array *tr)
+static int function_trace_init(struct trace_array *tr)
 {
 	func_trace = tr;
 	tr->cpu = get_cpu();
-	tracing_reset_online_cpus(tr);
 	put_cpu();
 
 	tracing_start_cmdline_record();
 	tracing_start_function_trace();
-}
-
-static void stop_function_trace(struct trace_array *tr)
-{
-	tracing_stop_function_trace();
-	tracing_stop_cmdline_record();
-}
-
-static int function_trace_init(struct trace_array *tr)
-{
-	start_function_trace(tr);
 	return 0;
 }
 
 static void function_trace_reset(struct trace_array *tr)
 {
-	stop_function_trace(tr);
+	tracing_stop_function_trace();
+	tracing_stop_cmdline_record();
 }
 
 static void function_trace_start(struct trace_array *tr)
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index c97594d826b..222f97d336a 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -56,7 +56,6 @@ static int graph_trace_init(struct trace_array *tr)
 					&trace_graph_entry);
 	if (ret)
 		return ret;
-	tracing_reset_online_cpus(tr);
 	tracing_start_cmdline_record();
 
 	return 0;
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index 2aa1c9f4c7d..ca4bbcfb9e2 100644
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -132,7 +132,6 @@ static int bts_trace_init(struct trace_array *tr)
 	hw_branch_trace = tr;
 
 	register_hotcpu_notifier(&bts_hotcpu_notifier);
-	tracing_reset_online_cpus(tr);
 	bts_trace_start(tr);
 
 	return 0;
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index 087b6cbf4ea..9aa84bde23c 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -48,7 +48,6 @@ static void stop_nop_trace(struct trace_array *tr)
 static int nop_trace_init(struct trace_array *tr)
 {
 	ctx_trace = tr;
-	tracing_reset_online_cpus(tr);
 	start_nop_trace(tr);
 	return 0;
 }
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index c4f9add5ec9..30e14fe8589 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -185,12 +185,6 @@ void tracing_sched_switch_assign_trace(struct trace_array *tr)
 	ctx_trace = tr;
 }
 
-static void start_sched_trace(struct trace_array *tr)
-{
-	tracing_reset_online_cpus(tr);
-	tracing_start_sched_switch_record();
-}
-
 static void stop_sched_trace(struct trace_array *tr)
 {
 	tracing_stop_sched_switch_record();
@@ -199,7 +193,7 @@ static void stop_sched_trace(struct trace_array *tr)
 static int sched_switch_trace_init(struct trace_array *tr)
 {
 	ctx_trace = tr;
-	start_sched_trace(tr);
+	tracing_start_sched_switch_record();
 	return 0;
 }
 
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 5013812578b..445700e51f6 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -115,7 +115,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 	ftrace_set_filter(func_name, strlen(func_name), 1);
 
 	/* enable tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		goto out;
@@ -189,7 +189,7 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
 	ftrace_enabled = 1;
 	tracer_enabled = 1;
 
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		goto out;
@@ -236,7 +236,7 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
 	int ret;
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return ret;
@@ -290,7 +290,7 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
 	}
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return ret;
@@ -344,7 +344,7 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
 	}
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		goto out;
@@ -476,7 +476,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
 	wait_for_completion(&isrt);
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return ret;
@@ -537,7 +537,7 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr
 	int ret;
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return ret;
@@ -569,7 +569,7 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
 	int ret;
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return 0;
@@ -596,7 +596,7 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
 	int ret;
 
 	/* start the tracing */
-	ret = trace->init(tr);
+	ret = tracer_init(trace, tr);
 	if (ret) {
 		warn_failed_init_tracer(trace, ret);
 		return ret;
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index eaca5ad803f..84ca9d81e74 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -226,15 +226,6 @@ static void stop_stack_timers(void)
 		stop_stack_timer(cpu);
 }
 
-static void start_stack_trace(struct trace_array *tr)
-{
-	mutex_lock(&sample_timer_lock);
-	tracing_reset_online_cpus(tr);
-	start_stack_timers();
-	tracer_enabled = 1;
-	mutex_unlock(&sample_timer_lock);
-}
-
 static void stop_stack_trace(struct trace_array *tr)
 {
 	mutex_lock(&sample_timer_lock);
@@ -247,7 +238,10 @@ static int stack_trace_init(struct trace_array *tr)
 {
 	sysprof_trace = tr;
 
-	start_stack_trace(tr);
+	mutex_lock(&sample_timer_lock);
+	start_stack_timers();
+	tracer_enabled = 1;
+	mutex_unlock(&sample_timer_lock);
 	return 0;
 }
 
-- 
cgit v1.2.3-70-g09d2


From 73d8b8bc4f24a97a406d09c8268ac019f4ac661e Mon Sep 17 00:00:00 2001
From: Wenji Huang <wenji.huang@oracle.com>
Date: Tue, 17 Feb 2009 01:10:02 -0500
Subject: tracing: fix typing mistake in hint message and comments

Impact: cleanup

Fix incorrect hint message in code and typos in comments.

Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
 kernel/trace/trace_irqsoff.c      | 2 +-
 kernel/trace/trace_sched_switch.c | 2 +-
 kernel/trace/trace_sched_wakeup.c | 2 +-
 kernel/trace/trace_selftest.c     | 4 ++--
 kernel/trace/trace_stat.c         | 2 +-
 kernel/trace/trace_sysprof.c      | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index c6b442d88de..9e5ebd84415 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -1,5 +1,5 @@
 /*
- * trace irqs off criticall timings
+ * trace irqs off critical timings
  *
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 30e14fe8589..82fbb5a2df8 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -93,7 +93,7 @@ static int tracing_sched_register(void)
 	ret = register_trace_sched_switch(probe_sched_switch);
 	if (ret) {
 		pr_info("sched trace: Couldn't activate tracepoint"
-			" probe to kernel_sched_schedule\n");
+			" probe to kernel_sched_switch\n");
 		goto fail_deprobe_wake_new;
 	}
 
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 96d71648589..276c51aaf31 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -284,7 +284,7 @@ static void start_wakeup_tracer(struct trace_array *tr)
 	ret = register_trace_sched_switch(probe_wakeup_sched_switch);
 	if (ret) {
 		pr_info("sched trace: Couldn't activate tracepoint"
-			" probe to kernel_sched_schedule\n");
+			" probe to kernel_sched_switch\n");
 		goto fail_deprobe_wake_new;
 	}
 
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index c72e749bcbe..01415f4edaa 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -107,9 +107,9 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
 	func();
 
 	/*
-	 * Some archs *cough*PowerPC*cough* add charachters to the
+	 * Some archs *cough*PowerPC*cough* add characters to the
 	 * start of the function names. We simply put a '*' to
-	 * accomodate them.
+	 * accommodate them.
 	 */
 	func_name = "*" STR(DYN_FTRACE_TEST_NAME);
 
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index eae9cef3929..39310e3434e 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -30,7 +30,7 @@ struct tracer_stat_session {
 	struct dentry		*file;
 };
 
-/* All of the sessions currently in use. Each stat file embeed one session */
+/* All of the sessions currently in use. Each stat file embed one session */
 static LIST_HEAD(all_stat_sessions);
 static DEFINE_MUTEX(all_stat_sessions_mutex);
 
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index 7c9a2d82a7d..c771af4e8f1 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -327,5 +327,5 @@ void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
 			d_tracer, NULL, &sysprof_sample_fops);
 	if (entry)
 		return;
-	pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");
+	pr_warning("Could not create debugfs 'sysprof_sample_period' entry\n");
 }
-- 
cgit v1.2.3-70-g09d2


From 6eaaa5d57e76c454479833fc8594cd7c3b75c789 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Wed, 11 Feb 2009 02:25:00 +0100
Subject: tracing/core: use appropriate waiting on trace_pipe

Impact: api and pipe waiting change

Currently, the waiting used in tracing_read_pipe() is done through a
100 msecs schedule_timeout() loop which periodically check if there
are traces on the buffer.

This can cause small latencies for programs which are reading the incoming
events.

This patch makes the reader waiting for the trace_wait waitqueue except
for few tracers such as the sched and functions tracers which might be
already hold the runqueue lock while waking up the reader.

This is performed through a new callback wait_pipe() on struct tracer.
If none is implemented on a specific tracer, the default waiting for
trace_wait queue is attached.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/trace/trace.c                 | 62 ++++++++++++++++++++++++------------
 kernel/trace/trace.h                 | 25 +++++++++++++--
 kernel/trace/trace_functions.c       |  1 +
 kernel/trace/trace_functions_graph.c |  1 +
 kernel/trace/trace_sched_switch.c    |  1 +
 kernel/trace/trace_sched_wakeup.c    |  1 +
 6 files changed, 67 insertions(+), 24 deletions(-)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dc61e82faad..881a94474d7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -499,6 +499,9 @@ __acquires(kernel_lock)
 	else
 		if (!type->flags->opts)
 			type->flags->opts = dummy_tracer_opt;
+	if (!type->wait_pipe)
+		type->wait_pipe = default_wait_pipe;
+
 
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 	if (type->selftest && !tracing_selftest_disabled) {
@@ -1064,7 +1067,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
 	entry->next_prio		= wakee->prio;
 	entry->next_state		= wakee->state;
 	entry->next_cpu			= task_cpu(wakee);
-	trace_buffer_unlock_commit(tr, event, flags, pc);
+
+	ring_buffer_unlock_commit(tr->buffer, event);
+	ftrace_trace_stack(tr, flags, 6, pc);
+	ftrace_trace_userstack(tr, flags, pc);
 }
 
 void
@@ -2392,6 +2398,38 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
 	}
 }
 
+
+void default_wait_pipe(struct trace_iterator *iter)
+{
+	DEFINE_WAIT(wait);
+
+	prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
+
+	if (trace_empty(iter))
+		schedule();
+
+	finish_wait(&trace_wait, &wait);
+}
+
+/*
+ * This is a make-shift waitqueue.
+ * A tracer might use this callback on some rare cases:
+ *
+ *  1) the current tracer might hold the runqueue lock when it wakes up
+ *     a reader, hence a deadlock (sched, function, and function graph tracers)
+ *  2) the function tracers, trace all functions, we don't want
+ *     the overhead of calling wake_up and friends
+ *     (and tracing them too)
+ *
+ *     Anyway, this is really very primitive wakeup.
+ */
+void poll_wait_pipe(struct trace_iterator *iter)
+{
+	set_current_state(TASK_INTERRUPTIBLE);
+	/* sleep for 100 msecs, and try again. */
+	schedule_timeout(HZ / 10);
+}
+
 /* Must be called with trace_types_lock mutex held. */
 static int tracing_wait_pipe(struct file *filp)
 {
@@ -2403,30 +2441,14 @@ static int tracing_wait_pipe(struct file *filp)
 			return -EAGAIN;
 		}
 
-		/*
-		 * This is a make-shift waitqueue. The reason we don't use
-		 * an actual wait queue is because:
-		 *  1) we only ever have one waiter
-		 *  2) the tracing, traces all functions, we don't want
-		 *     the overhead of calling wake_up and friends
-		 *     (and tracing them too)
-		 *     Anyway, this is really very primitive wakeup.
-		 */
-		set_current_state(TASK_INTERRUPTIBLE);
-		iter->tr->waiter = current;
-
 		mutex_unlock(&trace_types_lock);
 
-		/* sleep for 100 msecs, and try again. */
-		schedule_timeout(HZ/10);
+		iter->trace->wait_pipe(iter);
 
 		mutex_lock(&trace_types_lock);
 
-		iter->tr->waiter = NULL;
-
-		if (signal_pending(current)) {
+		if (signal_pending(current))
 			return -EINTR;
-		}
 
 		if (iter->trace != current_trace)
 			return 0;
@@ -2442,8 +2464,6 @@ static int tracing_wait_pipe(struct file *filp)
 		 */
 		if (!tracer_enabled && iter->pos)
 			break;
-
-		continue;
 	}
 
 	return 1;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dbff0207b21..eed732c151f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -337,18 +337,34 @@ struct tracer_flags {
 #define TRACER_OPT(s, b)	.name = #s, .bit = b
 
 
-/*
- * A specific tracer, represented by methods that operate on a trace array:
+/**
+ * struct tracer - a specific tracer and its callbacks to interact with debugfs
+ * @name: the name chosen to select it on the available_tracers file
+ * @init: called when one switches to this tracer (echo name > current_tracer)
+ * @reset: called when one switches to another tracer
+ * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
+ * @stop: called when tracing is paused (echo 0 > tracing_enabled)
+ * @open: called when the trace file is opened
+ * @pipe_open: called when the trace_pipe file is opened
+ * @wait_pipe: override how the user waits for traces on trace_pipe
+ * @close: called when the trace file is released
+ * @read: override the default read callback on trace_pipe
+ * @splice_read: override the default splice_read callback on trace_pipe
+ * @selftest: selftest to run on boot (see trace_selftest.c)
+ * @print_headers: override the first lines that describe your columns
+ * @print_line: callback that prints a trace
+ * @set_flag: signals one of your private flags changed (trace_options file)
+ * @flags: your private flags
  */
 struct tracer {
 	const char		*name;
-	/* Your tracer should raise a warning if init fails */
 	int			(*init)(struct trace_array *tr);
 	void			(*reset)(struct trace_array *tr);
 	void			(*start)(struct trace_array *tr);
 	void			(*stop)(struct trace_array *tr);
 	void			(*open)(struct trace_iterator *iter);
 	void			(*pipe_open)(struct trace_iterator *iter);
+	void			(*wait_pipe)(struct trace_iterator *iter);
 	void			(*close)(struct trace_iterator *iter);
 	ssize_t			(*read)(struct trace_iterator *iter,
 					struct file *filp, char __user *ubuf,
@@ -432,6 +448,9 @@ void tracing_generic_entry_update(struct trace_entry *entry,
 				  unsigned long flags,
 				  int pc);
 
+void default_wait_pipe(struct trace_iterator *iter);
+void poll_wait_pipe(struct trace_iterator *iter);
+
 void ftrace(struct trace_array *tr,
 			    struct trace_array_cpu *data,
 			    unsigned long ip,
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 4c113a8c466..c9a0b7df44f 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -225,6 +225,7 @@ static struct tracer function_trace __read_mostly =
 	.init		= function_trace_init,
 	.reset		= function_trace_reset,
 	.start		= function_trace_start,
+	.wait_pipe	= poll_wait_pipe,
 	.flags		= &func_flags,
 	.set_flag	= func_set_flag,
 #ifdef CONFIG_FTRACE_SELFTEST
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 519a0cab153..0ff5cb66190 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -757,6 +757,7 @@ static struct tracer graph_trace __read_mostly = {
 	.name	     	= "function_graph",
 	.open		= graph_trace_open,
 	.close		= graph_trace_close,
+	.wait_pipe	= poll_wait_pipe,
 	.init	     	= graph_trace_init,
 	.reset	     	= graph_trace_reset,
 	.print_line	= print_graph_function,
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 82fbb5a2df8..77132c2cf3d 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -221,6 +221,7 @@ static struct tracer sched_switch_trace __read_mostly =
 	.reset		= sched_switch_trace_reset,
 	.start		= sched_switch_trace_start,
 	.stop		= sched_switch_trace_stop,
+	.wait_pipe	= poll_wait_pipe,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest    = trace_selftest_startup_sched_switch,
 #endif
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 276c51aaf31..db55f7aaa64 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -380,6 +380,7 @@ static struct tracer wakeup_rt_tracer __read_mostly =
 	.reset		= wakeup_tracer_reset,
 	.start		= wakeup_tracer_start,
 	.stop		= wakeup_tracer_stop,
+	.wait_pipe	= poll_wait_pipe,
 	.print_max	= 1,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest    = trace_selftest_startup_wakeup,
-- 
cgit v1.2.3-70-g09d2


From 5fec6ddcb43a91aa9a254c8ecf174c803de6f07e Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Tue, 17 Mar 2009 19:59:53 -0400
Subject: tracing: make sched_switch stop/start light weight

The stopping and starting of a tracer should be light weight and
be able to be called in all contexts. The sched_switch grabbed
mutexes in the start/stop functions. This patch changes it to a
simple variable, on/off.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
---
 kernel/trace/trace_sched_switch.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 77132c2cf3d..de35f200abd 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -18,6 +18,7 @@ static struct trace_array	*ctx_trace;
 static int __read_mostly	tracer_enabled;
 static int			sched_ref;
 static DEFINE_MUTEX(sched_register_mutex);
+static int			sched_stopped;
 
 static void
 probe_sched_switch(struct rq *__rq, struct task_struct *prev,
@@ -28,7 +29,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 	int cpu;
 	int pc;
 
-	if (!sched_ref)
+	if (!sched_ref || sched_stopped)
 		return;
 
 	tracing_record_cmdline(prev);
@@ -193,6 +194,7 @@ static void stop_sched_trace(struct trace_array *tr)
 static int sched_switch_trace_init(struct trace_array *tr)
 {
 	ctx_trace = tr;
+	tracing_reset_online_cpus(tr);
 	tracing_start_sched_switch_record();
 	return 0;
 }
@@ -205,13 +207,12 @@ static void sched_switch_trace_reset(struct trace_array *tr)
 
 static void sched_switch_trace_start(struct trace_array *tr)
 {
-	tracing_reset_online_cpus(tr);
-	tracing_start_sched_switch();
+	sched_stopped = 0;
 }
 
 static void sched_switch_trace_stop(struct trace_array *tr)
 {
-	tracing_stop_sched_switch();
+	sched_stopped = 1;
 }
 
 static struct tracer sched_switch_trace __read_mostly =
-- 
cgit v1.2.3-70-g09d2


From 8bcae09b93e7f96f700b6bb372c2b3f2b36636dc Mon Sep 17 00:00:00 2001
From: Zhaolei <zhaolei@cn.fujitsu.com>
Date: Tue, 31 Mar 2009 15:24:51 +0800
Subject: ftrace: Add check of sched_stopped for probe_sched_wakeup

The wakeup tracing in sched_switch does not stop when a user
disables tracing. This is because the probe_sched_wakeup() is missing
the check to prevent the wakeup from being traced.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <49D1C543.3010307@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/trace/trace_sched_switch.c | 3 +++
 1 file changed, 3 insertions(+)

(limited to 'kernel/trace/trace_sched_switch.c')

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index de35f200abd..9117cea6f1a 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -62,6 +62,9 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 	pc = preempt_count();
 	tracing_record_cmdline(current);
 
+	if (sched_stopped)
+		return;
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = ctx_trace->data[cpu];
-- 
cgit v1.2.3-70-g09d2