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Commit 5079f326 authored by Zhaolei's avatar Zhaolei Committed by Steven Rostedt
Browse files

ftrace: Move setting of clock-source out of options 



There are many clock sources for the tracing system but we can only
enable/disable one at a time with the trace/options file.
We can move the setting of clock-source out of options and add a separate
file for it:
 # cat trace_clock
 [local] global
 # echo global > trace_clock
 # cat trace_clock
 local [global]

Signed-off-by: default avatarZhao Lei <zhaolei@cn.fujitsu.com>
LKML-Reference: <4A939D08.6050604@cn.fujitsu.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 87a342f5

kernel/trace/trace.c

+75 −17
Original line number Diff line number Diff line
@@ -323,12 +323,21 @@ static const char *trace_options[] = { 
	"printk-msg-only",

	"context-info",

	"latency-format",

	"global-clock",

	"sleep-time",

	"graph-time",

	NULL

};



static struct {

	u64 (*func)(void);

	const char *name;

} trace_clocks[] = {

	{ trace_clock_local,	"local" },

	{ trace_clock_global,	"global" },

};



int trace_clock_id;



/*

 * ftrace_max_lock is used to protect the swapping of buffers

 * when taking a max snapshot. The buffers themselves are
@@ -2159,22 +2168,6 @@ static void set_tracer_flags(unsigned int mask, int enabled) 
		trace_flags |= mask;

	else

		trace_flags &= ~mask;



	if (mask == TRACE_ITER_GLOBAL_CLK) {

		u64 (*func)(void);



		if (enabled)

			func = trace_clock_global;

		else

			func = trace_clock_local;



		mutex_lock(&trace_types_lock);

		ring_buffer_set_clock(global_trace.buffer, func);



		if (max_tr.buffer)

			ring_buffer_set_clock(max_tr.buffer, func);

		mutex_unlock(&trace_types_lock);

	}

}



static ssize_t
@@ -3142,6 +3135,62 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, 
	return cnt;

}



static ssize_t tracing_clock_read(struct file *filp, char __user *ubuf,

				  size_t cnt, loff_t *ppos)

{

	char buf[64];

	int bufiter = 0;

	int i;



	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)

		bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter,

			"%s%s%s%s", i ? " " : "",

			i == trace_clock_id ? "[" : "", trace_clocks[i].name,

			i == trace_clock_id ? "]" : "");

	bufiter += snprintf(buf + bufiter, sizeof(buf) - bufiter, "\n");



	return simple_read_from_buffer(ubuf, cnt, ppos, buf, bufiter);

}



static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,

				   size_t cnt, loff_t *fpos)

{

	char buf[64];

	const char *clockstr;

	int i;



	if (cnt >= sizeof(buf))

		return -EINVAL;



	if (copy_from_user(&buf, ubuf, cnt))

		return -EFAULT;



	buf[cnt] = 0;



	clockstr = strstrip(buf);



	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {

		if (strcmp(trace_clocks[i].name, clockstr) == 0)

			break;

	}

	if (i == ARRAY_SIZE(trace_clocks))

		return -EINVAL;



	trace_clock_id = i;



	mutex_lock(&trace_types_lock);



	ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);

	if (max_tr.buffer)

		ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);



	mutex_unlock(&trace_types_lock);



	*fpos += cnt;



	return cnt;

}



static const struct file_operations tracing_max_lat_fops = {

	.open		= tracing_open_generic,

	.read		= tracing_max_lat_read,
@@ -3179,6 +3228,12 @@ static const struct file_operations tracing_mark_fops = { 
	.write		= tracing_mark_write,

};



static const struct file_operations trace_clock_fops = {

	.open		= tracing_open_generic,

	.read		= tracing_clock_read,

	.write		= tracing_clock_write,

};



struct ftrace_buffer_info {

	struct trace_array	*tr;

	void			*spare;
@@ -3918,6 +3973,9 @@ static __init int tracer_init_debugfs(void) 
	trace_create_file("saved_cmdlines", 0444, d_tracer,

			NULL, &tracing_saved_cmdlines_fops);



	trace_create_file("trace_clock", 0644, d_tracer, NULL,

			  &trace_clock_fops);



#ifdef CONFIG_DYNAMIC_FTRACE

	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,

			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);

kernel/trace/trace.h

+4 −3
Original line number Diff line number Diff line
@@ -568,6 +568,8 @@ trace_vprintk(unsigned long ip, const char *fmt, va_list args); 


extern unsigned long trace_flags;



extern int trace_clock_id;



/* Standard output formatting function used for function return traces */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

extern enum print_line_t print_graph_function(struct trace_iterator *iter);
@@ -656,9 +658,8 @@ enum trace_iterator_flags { 
	TRACE_ITER_PRINTK_MSGONLY	= 0x10000,

	TRACE_ITER_CONTEXT_INFO		= 0x20000, /* Print pid/cpu/time */

	TRACE_ITER_LATENCY_FMT		= 0x40000,

	TRACE_ITER_GLOBAL_CLK		= 0x80000,

	TRACE_ITER_SLEEP_TIME		= 0x100000,

	TRACE_ITER_GRAPH_TIME		= 0x200000,

	TRACE_ITER_SLEEP_TIME		= 0x80000,

	TRACE_ITER_GRAPH_TIME		= 0x100000,

};



/*