All of lore.kernel.org
 help / color / mirror / Atom feed
* [PATCH] tracing/events: add trace_event boot option
@ 2009-07-01  2:47 Li Zefan
  2009-07-01 14:01 ` [tip:tracing/core] tracing/events: Add " tip-bot for Li Zefan
  0 siblings, 1 reply; 2+ messages in thread
From: Li Zefan @ 2009-07-01  2:47 UTC (permalink / raw)
  To: Ingo Molnar; +Cc: Steven Rostedt, Frederic Weisbecker, LKML

We already have ftrace= boot option, and this adds a similar
boot option for trace events, so allow trace events to be
enabled at boot, for boot debugging purpose.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 Documentation/kernel-parameters.txt |    5 ++++
 Documentation/trace/events.txt      |    9 ++++++++
 kernel/trace/trace.c                |    4 +-
 kernel/trace/trace.h                |    3 ++
 kernel/trace/trace_events.c         |   37 +++++++++++++++++++++++++++++++---
 5 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index d77fbd8..6f98ed7 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2476,6 +2476,11 @@ and is between 256 and 4096 characters. It is defined in the file
 	trace_buf_size=nn[KMG]
 			[FTRACE] will set tracing buffer size.
 
+	trace_event=[event-list]
+			[FTRACE] Set and start specified trace events in order
+			to facilitate early boot debugging.
+			See also Documentation/trace/events.txt
+
 	trix=		[HW,OSS] MediaTrix AudioTrix Pro
 			Format:
 			<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
index f157d75..2bcc8d4 100644
--- a/Documentation/trace/events.txt
+++ b/Documentation/trace/events.txt
@@ -83,6 +83,15 @@ When reading one of these enable files, there are four results:
  X - there is a mixture of events enabled and disabled
  ? - this file does not affect any event
 
+2.3 Boot option
+---------------
+
+In order to facilitate early boot debugging, use boot option:
+
+	trace_event=[event-list]
+
+The format of this boot option is the same as described in section 2.1.
+
 3. Defining an event-enabled tracepoint
 =======================================
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 3aa0a0d..bdb3afc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -49,7 +49,7 @@ unsigned long __read_mostly	tracing_thresh;
  * On boot up, the ring buffer is set to the minimum size, so that
  * we do not waste memory on systems that are not using tracing.
  */
-static int ring_buffer_expanded;
+int ring_buffer_expanded;
 
 /*
  * We need to change this state when a selftest is running.
@@ -63,7 +63,7 @@ static bool __read_mostly tracing_selftest_running;
 /*
  * If a tracer is running, we do not want to run SELFTEST.
  */
-static bool __read_mostly tracing_selftest_disabled;
+bool __read_mostly tracing_selftest_disabled;
 
 /* For tracers that don't implement custom flags */
 static struct tracer_opt dummy_tracer_opt[] = {
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 206cb7d..61b4e94 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -538,6 +538,9 @@ extern unsigned long ftrace_update_tot_cnt;
 extern int DYN_FTRACE_TEST_NAME(void);
 #endif
 
+extern int ring_buffer_expanded;
+extern bool tracing_selftest_disabled;
+
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 extern int trace_selftest_startup_function(struct tracer *trace,
 					   struct trace_array *tr);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53c8fd3..fecac13 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -17,6 +17,8 @@
 #include <linux/ctype.h>
 #include <linux/delay.h>
 
+#include <asm/setup.h>
+
 #include "trace_output.h"
 
 #define TRACE_SYSTEM "TRACE_SYSTEM"
@@ -1133,6 +1135,18 @@ struct notifier_block trace_module_nb = {
 extern struct ftrace_event_call __start_ftrace_events[];
 extern struct ftrace_event_call __stop_ftrace_events[];
 
+static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata;
+
+static __init int setup_trace_event(char *str)
+{
+	strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
+	ring_buffer_expanded = 1;
+	tracing_selftest_disabled = 1;
+
+	return 1;
+}
+__setup("trace_event=", setup_trace_event);
+
 static __init int event_trace_init(void)
 {
 	struct ftrace_event_call *call;
@@ -1140,6 +1154,8 @@ static __init int event_trace_init(void)
 	struct dentry *entry;
 	struct dentry *d_events;
 	int ret;
+	char *buf = bootup_event_buf;
+	char *token;
 
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
@@ -1185,6 +1201,19 @@ static __init int event_trace_init(void)
 				 &ftrace_event_format_fops);
 	}
 
+	while (true) {
+		token = strsep(&buf, ",");
+
+		if (!token)
+			break;
+		if (!*token)
+			continue;
+
+		ret = ftrace_set_clr_event(token, 1);
+		if (ret)
+			pr_warning("Failed to enable trace event: %s\n", token);
+	}
+
 	ret = register_module_notifier(&trace_module_nb);
 	if (ret)
 		pr_warning("Failed to register trace events module notifier\n");
@@ -1392,10 +1421,10 @@ static __init void event_trace_self_test_with_function(void)
 
 static __init int event_trace_self_tests_init(void)
 {
-
-	event_trace_self_tests();
-
-	event_trace_self_test_with_function();
+	if (!tracing_selftest_disabled) {
+		event_trace_self_tests();
+		event_trace_self_test_with_function();
+	}
 
 	return 0;
 }
-- 
1.5.4.rc3


^ permalink raw reply related	[flat|nested] 2+ messages in thread
end of thread, other threads:[~2009-07-01 14:01 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-07-01  2:47 [PATCH] tracing/events: add trace_event boot option Li Zefan
2009-07-01 14:01 ` [tip:tracing/core] tracing/events: Add " tip-bot for Li Zefan

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.