ftrace: add traceon traceoff commands to enable/disable the buffers

This patch adds the new function selection commands traceon and traceoff. traceon sets the function to enable the ring buffers while traceoff disables the ring buffers. You can pass in the number of times you want the command to be executed when the function is hit. It will only execute if the state of the buffers are not already in that state. Example: # echo do_fork:traceon:4 Will enable the ring buffers if they are disabled every time it hits do_fork, up to 4 times. # echo sys_close:traceoff This will disable the ring buffers every time (unlimited) when sys_close is called. Signed-off-by: Steven Rostedt <srostedt@redhat.com>

ftrace: add traceon traceoff commands to enable/disable the buffers
This patch adds the new function selection commands traceon and traceoff. traceon sets the function to enable the ring buffers while traceoff disables the ring buffers. You can pass in the number of times you want the command to be executed when the function is hit. It will only execute if the state of the buffers are not already in that state. Example: # echo do_fork:traceon:4 Will enable the ring buffers if they are disabled every time it hits do_fork, up to 4 times. # echo sys_close:traceoff This will disable the ring buffers every time (unlimited) when sys_close is called. Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Steven Rostedt
1 parent 988ae9d6b2
Showing 1 changed file with 135 additions and 0 deletions Side-by-side Diff
kernel/trace/trace_functions.c
@@ -9,6 +9,7 @@
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 William Lee Irwin III
  */
+#include <linux/ring_buffer.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
  
@@ -231,8 +232,141 @@
 #endif
 };
  
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void
+ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
+{
+	long *count = (long *)data;
+
+	if (tracing_is_on())
+		return;
+
+	if (!*count)
+		return;
+
+	if (*count != -1)
+		(*count)--;
+
+	tracing_on();
+}
+
+static void
+ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
+{
+	long *count = (long *)data;
+
+	if (!tracing_is_on())
+		return;
+
+	if (!*count)
+		return;
+
+	if (*count != -1)
+		(*count)--;
+
+	tracing_off();
+}
+
+static struct ftrace_hook_ops traceon_hook_ops = {
+	.func			= ftrace_traceon,
+};
+
+static struct ftrace_hook_ops traceoff_hook_ops = {
+	.func			= ftrace_traceoff,
+};
+
+static int
+ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param)
+{
+	struct ftrace_hook_ops *ops;
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = &traceon_hook_ops;
+	else
+		ops = &traceoff_hook_ops;
+
+	unregister_ftrace_function_hook_func(glob, ops);
+
+	return 0;
+}
+
+static int
+ftrace_trace_onoff_callback(char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_hook_ops *ops;
+	void *count = (void *)-1;
+	char *number;
+	int ret;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enable)
+		return -EINVAL;
+
+	if (glob[0] == '!')
+		return ftrace_trace_onoff_unreg(glob+1, cmd, param);
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = &traceon_hook_ops;
+	else
+		ops = &traceoff_hook_ops;
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	if (!strlen(number))
+		goto out_reg;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = strict_strtoul(number, 0, (unsigned long *)&count);
+	if (ret)
+		return ret;
+
+ out_reg:
+	ret = register_ftrace_function_hook(glob, ops, count);
+
+	return ret;
+}
+
+static struct ftrace_func_command ftrace_traceon_cmd = {
+	.name			= "traceon",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static struct ftrace_func_command ftrace_traceoff_cmd = {
+	.name			= "traceoff",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static int __init init_func_cmd_traceon(void)
+{
+	int ret;
+
+	ret = register_ftrace_command(&ftrace_traceoff_cmd);
+	if (ret)
+		return ret;
+
+	ret = register_ftrace_command(&ftrace_traceon_cmd);
+	if (ret)
+		unregister_ftrace_command(&ftrace_traceoff_cmd);
+	return ret;
+}
+#else
+static inline int init_func_cmd_traceon(void)
+{
+	return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 static __init int init_function_trace(void)
 {
+	init_func_cmd_traceon();
 	return register_tracer(&function_trace);
 }
...	...	@@ -9,6 +9,7 @@
9	9	* Copyright (C) 2004-2006 Ingo Molnar
10	10	* Copyright (C) 2004 William Lee Irwin III
11	11	*/
	12	+#include <linux/ring_buffer.h>
12	13	#include <linux/debugfs.h>
13	14	#include <linux/uaccess.h>
14	15	#include <linux/ftrace.h>
15	16
...	...	@@ -231,8 +232,141 @@
231	232	#endif
232	233	};
233	234
	235	+#ifdef CONFIG_DYNAMIC_FTRACE
	236	+static void
	237	+ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
	238	+{
	239	+ long count = (long )data;
	240	+
	241	+ if (tracing_is_on())
	242	+ return;
	243	+
	244	+ if (!*count)
	245	+ return;
	246	+
	247	+ if (*count != -1)
	248	+ (*count)--;
	249	+
	250	+ tracing_on();
	251	+}
	252	+
	253	+static void
	254	+ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
	255	+{
	256	+ long count = (long )data;
	257	+
	258	+ if (!tracing_is_on())
	259	+ return;
	260	+
	261	+ if (!*count)
	262	+ return;
	263	+
	264	+ if (*count != -1)
	265	+ (*count)--;
	266	+
	267	+ tracing_off();
	268	+}
	269	+
	270	+static struct ftrace_hook_ops traceon_hook_ops = {
	271	+ .func = ftrace_traceon,
	272	+};
	273	+
	274	+static struct ftrace_hook_ops traceoff_hook_ops = {
	275	+ .func = ftrace_traceoff,
	276	+};
	277	+
	278	+static int
	279	+ftrace_trace_onoff_unreg(char glob, char cmd, char *param)
	280	+{
	281	+ struct ftrace_hook_ops *ops;
	282	+
	283	+ /* we register both traceon and traceoff to this callback */
	284	+ if (strcmp(cmd, "traceon") == 0)
	285	+ ops = &traceon_hook_ops;
	286	+ else
	287	+ ops = &traceoff_hook_ops;
	288	+
	289	+ unregister_ftrace_function_hook_func(glob, ops);
	290	+
	291	+ return 0;
	292	+}
	293	+
	294	+static int
	295	+ftrace_trace_onoff_callback(char glob, char cmd, char *param, int enable)
	296	+{
	297	+ struct ftrace_hook_ops *ops;
	298	+ void count = (void )-1;
	299	+ char *number;
	300	+ int ret;
	301	+
	302	+ /* hash funcs only work with set_ftrace_filter */
	303	+ if (!enable)
	304	+ return -EINVAL;
	305	+
	306	+ if (glob[0] == '!')
	307	+ return ftrace_trace_onoff_unreg(glob+1, cmd, param);
	308	+
	309	+ /* we register both traceon and traceoff to this callback */
	310	+ if (strcmp(cmd, "traceon") == 0)
	311	+ ops = &traceon_hook_ops;
	312	+ else
	313	+ ops = &traceoff_hook_ops;
	314	+
	315	+ if (!param)
	316	+ goto out_reg;
	317	+
	318	+ number = strsep(&param, ":");
	319	+
	320	+ if (!strlen(number))
	321	+ goto out_reg;
	322	+
	323	+ /*
	324	+ * We use the callback data field (which is a pointer)
	325	+ * as our counter.
	326	+ */
	327	+ ret = strict_strtoul(number, 0, (unsigned long *)&count);
	328	+ if (ret)
	329	+ return ret;
	330	+
	331	+ out_reg:
	332	+ ret = register_ftrace_function_hook(glob, ops, count);
	333	+
	334	+ return ret;
	335	+}
	336	+
	337	+static struct ftrace_func_command ftrace_traceon_cmd = {
	338	+ .name = "traceon",
	339	+ .func = ftrace_trace_onoff_callback,
	340	+};
	341	+
	342	+static struct ftrace_func_command ftrace_traceoff_cmd = {
	343	+ .name = "traceoff",
	344	+ .func = ftrace_trace_onoff_callback,
	345	+};
	346	+
	347	+static int __init init_func_cmd_traceon(void)
	348	+{
	349	+ int ret;
	350	+
	351	+ ret = register_ftrace_command(&ftrace_traceoff_cmd);
	352	+ if (ret)
	353	+ return ret;
	354	+
	355	+ ret = register_ftrace_command(&ftrace_traceon_cmd);
	356	+ if (ret)
	357	+ unregister_ftrace_command(&ftrace_traceoff_cmd);
	358	+ return ret;
	359	+}
	360	+#else
	361	+static inline int init_func_cmd_traceon(void)
	362	+{
	363	+ return 0;
	364	+}
	365	+#endif /* CONFIG_DYNAMIC_FTRACE */
	366	+
234	367	static __init int init_function_trace(void)
235	368	{
	369	+ init_func_cmd_traceon();
236	370	return register_tracer(&function_trace);
237	371	}
238	372