Merge branch 'tracing/sysprof' into auto-ftrace-next

Ingo Molnar
2 parents 5373fdbdc1 37f5d732f3
Showing 6 changed files Side-by-side Diff
kernel/trace/Kconfig
kernel/trace/Makefile
kernel/trace/trace.c
kernel/trace/trace.h
kernel/trace/trace_selftest.c
kernel/trace/trace_sysprof.c
@@ -75,6 +75,14 @@
 	  enabled. This option and the irqs-off timing option can be
 	  used together or separately.)
  
+config SYSPROF_TRACER
+	bool "Sysprof Tracer"
+	depends on X86
+	select TRACING
+	help
+	  This tracer provides the trace needed by the 'Sysprof' userspace
+	  tool.
+
 config SCHED_TRACER
 	bool "Scheduling Latency Tracer"
 	depends on HAVE_FTRACE
@@ -14,6 +14,7 @@
  
 obj-$(CONFIG_TRACING) += trace.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
+obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o
 obj-$(CONFIG_FTRACE) += trace_functions.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
@@ -2913,6 +2913,9 @@
 		pr_warning("Could not create debugfs "
 			   "'dyn_ftrace_total_info' entry\n");
 #endif
+#ifdef CONFIG_SYSPROF_TRACER
+	init_tracer_sysprof_debugfs(d_tracer);
+#endif
 }
  
 static int trace_alloc_page(void)
@@ -193,6 +193,8 @@
 void tracing_reset(struct trace_array_cpu *data);
 int tracing_open_generic(struct inode *inode, struct file *filp);
 struct dentry *tracing_init_dentry(void);
+void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
+
 void ftrace(struct trace_array *tr,
 			    struct trace_array_cpu *data,
 			    unsigned long ip,
@@ -292,6 +294,10 @@
 #endif
 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
+					       struct trace_array *tr);
+#endif
+#ifdef CONFIG_SYSPROF_TRACER
+extern int trace_selftest_startup_sysprof(struct tracer *trace,
 					       struct trace_array *tr);
 #endif
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
@@ -538,4 +538,27 @@
 	return ret;
 }
 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
+
+#ifdef CONFIG_SYSPROF_TRACER
+int
+trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
+{
+	unsigned long count;
+	int ret;
+
+	/* start the tracing */
+	tr->ctrl = 1;
+	trace->init(tr);
+	/* Sleep for a 1/10 of a second */
+	msleep(100);
+	/* stop the tracing. */
+	tr->ctrl = 0;
+	trace->ctrl_update(tr);
+	/* check the trace buffer */
+	ret = trace_test_buffer(tr, &count);
+	trace->reset(tr);
+
+	return ret;
+}
+#endif /* CONFIG_SYSPROF_TRACER */
+/*
+ * trace stack traces
+ *
+ * Copyright (C) 2004-2008, Soeren Sandmann
+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ */
+#include <linux/kallsyms.h>
+#include <linux/debugfs.h>
+#include <linux/hrtimer.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/irq.h>
+#include <linux/fs.h>
+
+#include <asm/stacktrace.h>
+
+#include "trace.h"
+
+static struct trace_array	*sysprof_trace;
+static int __read_mostly	tracer_enabled;
+
+/*
+ * 1 msec sample interval by default:
+ */
+static unsigned long sample_period = 1000000;
+static const unsigned int sample_max_depth = 512;
+
+static DEFINE_MUTEX(sample_timer_lock);
+/*
+ * Per CPU hrtimers that do the profiling:
+ */
+static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
+
+struct stack_frame {
+	const void __user	*next_fp;
+	unsigned long		return_address;
+};
+
+static int copy_stack_frame(const void __user *fp, struct stack_frame *frame)
+{
+	int ret;
+
+	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
+		return 0;
+
+	ret = 1;
+	pagefault_disable();
+	if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
+		ret = 0;
+	pagefault_enable();
+
+	return ret;
+}
+
+struct backtrace_info {
+	struct trace_array_cpu	*data;
+	struct trace_array	*tr;
+	int			pos;
+};
+
+static void
+backtrace_warning_symbol(void *data, char *msg, unsigned long symbol)
+{
+	/* Ignore warnings */
+}
+
+static void backtrace_warning(void *data, char *msg)
+{
+	/* Ignore warnings */
+}
+
+static int backtrace_stack(void *data, char *name)
+{
+	/* Don't bother with IRQ stacks for now */
+	return -1;
+}
+
+static void backtrace_address(void *data, unsigned long addr, int reliable)
+{
+	struct backtrace_info *info = data;
+
+	if (info->pos < sample_max_depth && reliable) {
+		__trace_special(info->tr, info->data, 1, addr, 0);
+
+		info->pos++;
+	}
+}
+
+const static struct stacktrace_ops backtrace_ops = {
+	.warning		= backtrace_warning,
+	.warning_symbol		= backtrace_warning_symbol,
+	.stack			= backtrace_stack,
+	.address		= backtrace_address,
+};
+
+static int
+trace_kernel(struct pt_regs *regs, struct trace_array *tr,
+	     struct trace_array_cpu *data)
+{
+	struct backtrace_info info;
+	unsigned long bp;
+	char *stack;
+
+	info.tr = tr;
+	info.data = data;
+	info.pos = 1;
+
+	__trace_special(info.tr, info.data, 1, regs->ip, 0);
+
+	stack = ((char *)regs + sizeof(struct pt_regs));
+#ifdef CONFIG_FRAME_POINTER
+	bp = regs->bp;
+#else
+	bp = 0;
+#endif
+
+	dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
+
+	return info.pos;
+}
+
+static void timer_notify(struct pt_regs *regs, int cpu)
+{
+	struct trace_array_cpu *data;
+	struct stack_frame frame;
+	struct trace_array *tr;
+	const void __user *fp;
+	int is_user;
+	int i;
+
+	if (!regs)
+		return;
+
+	tr = sysprof_trace;
+	data = tr->data[cpu];
+	is_user = user_mode(regs);
+
+	if (!current || current->pid == 0)
+		return;
+
+	if (is_user && current->state != TASK_RUNNING)
+		return;
+
+	__trace_special(tr, data, 0, 0, current->pid);
+
+	if (!is_user)
+		i = trace_kernel(regs, tr, data);
+	else
+		i = 0;
+
+	/*
+	 * Trace user stack if we are not a kernel thread
+	 */
+	if (current->mm && i < sample_max_depth) {
+		regs = (struct pt_regs *)current->thread.sp0 - 1;
+
+		fp = (void __user *)regs->bp;
+
+		__trace_special(tr, data, 2, regs->ip, 0);
+
+		while (i < sample_max_depth) {
+			frame.next_fp = 0;
+			frame.return_address = 0;
+			if (!copy_stack_frame(fp, &frame))
+				break;
+			if ((unsigned long)fp < regs->sp)
+				break;
+
+			__trace_special(tr, data, 2, frame.return_address,
+					(unsigned long)fp);
+			fp = frame.next_fp;
+
+			i++;
+		}
+
+	}
+
+	/*
+	 * Special trace entry if we overflow the max depth:
+	 */
+	if (i == sample_max_depth)
+		__trace_special(tr, data, -1, -1, -1);
+
+	__trace_special(tr, data, 3, current->pid, i);
+}
+
+static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
+{
+	/* trace here */
+	timer_notify(get_irq_regs(), smp_processor_id());
+
+	hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
+
+	return HRTIMER_RESTART;
+}
+
+static void start_stack_timer(int cpu)
+{
+	struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+
+	hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer->function = stack_trace_timer_fn;
+	hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
+
+	hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
+}
+
+static void start_stack_timers(void)
+{
+	cpumask_t saved_mask = current->cpus_allowed;
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
+		start_stack_timer(cpu);
+	}
+	set_cpus_allowed_ptr(current, &saved_mask);
+}
+
+static void stop_stack_timer(int cpu)
+{
+	struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+
+	hrtimer_cancel(hrtimer);
+}
+
+static void stop_stack_timers(void)
+{
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		stop_stack_timer(cpu);
+}
+
+static void stack_reset(struct trace_array *tr)
+{
+	int cpu;
+
+	tr->time_start = ftrace_now(tr->cpu);
+
+	for_each_online_cpu(cpu)
+		tracing_reset(tr->data[cpu]);
+}
+
+static void start_stack_trace(struct trace_array *tr)
+{
+	mutex_lock(&sample_timer_lock);
+	stack_reset(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);
+	stop_stack_timers();
+	tracer_enabled = 0;
+	mutex_unlock(&sample_timer_lock);
+}
+
+static void stack_trace_init(struct trace_array *tr)
+{
+	sysprof_trace = tr;
+
+	if (tr->ctrl)
+		start_stack_trace(tr);
+}
+
+static void stack_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_stack_trace(tr);
+}
+
+static void stack_trace_ctrl_update(struct trace_array *tr)
+{
+	/* When starting a new trace, reset the buffers */
+	if (tr->ctrl)
+		start_stack_trace(tr);
+	else
+		stop_stack_trace(tr);
+}
+
+static struct tracer stack_trace __read_mostly =
+{
+	.name		= "sysprof",
+	.init		= stack_trace_init,
+	.reset		= stack_trace_reset,
+	.ctrl_update	= stack_trace_ctrl_update,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_sysprof,
+#endif
+};
+
+__init static int init_stack_trace(void)
+{
+	return register_tracer(&stack_trace);
+}
+device_initcall(init_stack_trace);
+
+#define MAX_LONG_DIGITS 22
+
+static ssize_t
+sysprof_sample_read(struct file *filp, char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	char buf[MAX_LONG_DIGITS];
+	int r;
+
+	r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+sysprof_sample_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	char buf[MAX_LONG_DIGITS];
+	unsigned long val;
+
+	if (cnt > MAX_LONG_DIGITS-1)
+		cnt = MAX_LONG_DIGITS-1;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	val = simple_strtoul(buf, NULL, 10);
+	/*
+	 * Enforce a minimum sample period of 100 usecs:
+	 */
+	if (val < 100)
+		val = 100;
+
+	mutex_lock(&sample_timer_lock);
+	stop_stack_timers();
+	sample_period = val * 1000;
+	start_stack_timers();
+	mutex_unlock(&sample_timer_lock);
+
+	return cnt;
+}
+
+static struct file_operations sysprof_sample_fops = {
+	.read		= sysprof_sample_read,
+	.write		= sysprof_sample_write,
+};
+
+void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
+{
+	struct dentry *entry;
+
+	entry = debugfs_create_file("sysprof_sample_period", 0644,
+			d_tracer, NULL, &sysprof_sample_fops);
+	if (entry)
+		return;
+	pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");
+}
...	...	@@ -75,6 +75,14 @@
75	75	enabled. This option and the irqs-off timing option can be
76	76	used together or separately.)
77	77
	78	+config SYSPROF_TRACER
	79	+ bool "Sysprof Tracer"
	80	+ depends on X86
	81	+ select TRACING
	82	+ help
	83	+ This tracer provides the trace needed by the 'Sysprof' userspace
	84	+ tool.
	85	+
78	86	config SCHED_TRACER
79	87	bool "Scheduling Latency Tracer"
80	88	depends on HAVE_FTRACE
...	...	@@ -14,6 +14,7 @@
14	14
15	15	obj-$(CONFIG_TRACING) += trace.o
16	16	obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
	17	+obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o
17	18	obj-$(CONFIG_FTRACE) += trace_functions.o
18	19	obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
19	20	obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
...	...	@@ -2913,6 +2913,9 @@
2913	2913	pr_warning("Could not create debugfs "
2914	2914	"'dyn_ftrace_total_info' entry\n");
2915	2915	#endif
	2916	+#ifdef CONFIG_SYSPROF_TRACER
	2917	+ init_tracer_sysprof_debugfs(d_tracer);
	2918	+#endif
2916	2919	}
2917	2920
2918	2921	static int trace_alloc_page(void)
...	...	@@ -193,6 +193,8 @@
193	193	void tracing_reset(struct trace_array_cpu *data);
194	194	int tracing_open_generic(struct inode inode, struct file filp);
195	195	struct dentry *tracing_init_dentry(void);
	196	+void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
	197	+
196	198	void ftrace(struct trace_array *tr,
197	199	struct trace_array_cpu *data,
198	200	unsigned long ip,
...	...	@@ -292,6 +294,10 @@
292	294	#endif
293	295	#ifdef CONFIG_CONTEXT_SWITCH_TRACER
294	296	extern int trace_selftest_startup_sched_switch(struct tracer *trace,
	297	+ struct trace_array *tr);
	298	+#endif
	299	+#ifdef CONFIG_SYSPROF_TRACER
	300	+extern int trace_selftest_startup_sysprof(struct tracer *trace,
295	301	struct trace_array *tr);
296	302	#endif
297	303	#endif /* CONFIG_FTRACE_STARTUP_TEST */
...	...	@@ -538,4 +538,27 @@
538	538	return ret;
539	539	}
540	540	#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
	541	+
	542	+#ifdef CONFIG_SYSPROF_TRACER
	543	+int
	544	+trace_selftest_startup_sysprof(struct tracer trace, struct trace_array tr)
	545	+{
	546	+ unsigned long count;
	547	+ int ret;
	548	+
	549	+ /* start the tracing */
	550	+ tr->ctrl = 1;
	551	+ trace->init(tr);
	552	+ /* Sleep for a 1/10 of a second */
	553	+ msleep(100);
	554	+ /* stop the tracing. */
	555	+ tr->ctrl = 0;
	556	+ trace->ctrl_update(tr);
	557	+ /* check the trace buffer */
	558	+ ret = trace_test_buffer(tr, &count);
	559	+ trace->reset(tr);
	560	+
	561	+ return ret;
	562	+}
	563	+#endif /* CONFIG_SYSPROF_TRACER */
	1	+/*
	2	+ * trace stack traces
	3	+ *
	4	+ * Copyright (C) 2004-2008, Soeren Sandmann
	5	+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
	6	+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
	7	+ */
	8	+#include <linux/kallsyms.h>
	9	+#include <linux/debugfs.h>
	10	+#include <linux/hrtimer.h>
	11	+#include <linux/uaccess.h>
	12	+#include <linux/ftrace.h>
	13	+#include <linux/module.h>
	14	+#include <linux/irq.h>
	15	+#include <linux/fs.h>
	16	+
	17	+#include <asm/stacktrace.h>
	18	+
	19	+#include "trace.h"
	20	+
	21	+static struct trace_array *sysprof_trace;
	22	+static int __read_mostly tracer_enabled;
	23	+
	24	+/*
	25	+ * 1 msec sample interval by default:
	26	+ */
	27	+static unsigned long sample_period = 1000000;
	28	+static const unsigned int sample_max_depth = 512;
	29	+
	30	+static DEFINE_MUTEX(sample_timer_lock);
	31	+/*
	32	+ * Per CPU hrtimers that do the profiling:
	33	+ */
	34	+static DEFINE_PER_CPU(struct hrtimer, stack_trace_hrtimer);
	35	+
	36	+struct stack_frame {
	37	+ const void __user *next_fp;
	38	+ unsigned long return_address;
	39	+};
	40	+
	41	+static int copy_stack_frame(const void __user fp, struct stack_frame frame)
	42	+{
	43	+ int ret;
	44	+
	45	+ if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
	46	+ return 0;
	47	+
	48	+ ret = 1;
	49	+ pagefault_disable();
	50	+ if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
	51	+ ret = 0;
	52	+ pagefault_enable();
	53	+
	54	+ return ret;
	55	+}
	56	+
	57	+struct backtrace_info {
	58	+ struct trace_array_cpu *data;
	59	+ struct trace_array *tr;
	60	+ int pos;
	61	+};
	62	+
	63	+static void
	64	+backtrace_warning_symbol(void data, char msg, unsigned long symbol)
	65	+{
	66	+ /* Ignore warnings */
	67	+}
	68	+
	69	+static void backtrace_warning(void data, char msg)
	70	+{
	71	+ /* Ignore warnings */
	72	+}
	73	+
	74	+static int backtrace_stack(void data, char name)
	75	+{
	76	+ /* Don't bother with IRQ stacks for now */
	77	+ return -1;
	78	+}
	79	+
	80	+static void backtrace_address(void *data, unsigned long addr, int reliable)
	81	+{
	82	+ struct backtrace_info *info = data;
	83	+
	84	+ if (info->pos < sample_max_depth && reliable) {
	85	+ __trace_special(info->tr, info->data, 1, addr, 0);
	86	+
	87	+ info->pos++;
	88	+ }
	89	+}
	90	+
	91	+const static struct stacktrace_ops backtrace_ops = {
	92	+ .warning = backtrace_warning,
	93	+ .warning_symbol = backtrace_warning_symbol,
	94	+ .stack = backtrace_stack,
	95	+ .address = backtrace_address,
	96	+};
	97	+
	98	+static int
	99	+trace_kernel(struct pt_regs regs, struct trace_array tr,
	100	+ struct trace_array_cpu *data)
	101	+{
	102	+ struct backtrace_info info;
	103	+ unsigned long bp;
	104	+ char *stack;
	105	+
	106	+ info.tr = tr;
	107	+ info.data = data;
	108	+ info.pos = 1;
	109	+
	110	+ __trace_special(info.tr, info.data, 1, regs->ip, 0);
	111	+
	112	+ stack = ((char *)regs + sizeof(struct pt_regs));
	113	+#ifdef CONFIG_FRAME_POINTER
	114	+ bp = regs->bp;
	115	+#else
	116	+ bp = 0;
	117	+#endif
	118	+
	119	+ dump_trace(NULL, regs, (void *)stack, bp, &backtrace_ops, &info);
	120	+
	121	+ return info.pos;
	122	+}
	123	+
	124	+static void timer_notify(struct pt_regs *regs, int cpu)
	125	+{
	126	+ struct trace_array_cpu *data;
	127	+ struct stack_frame frame;
	128	+ struct trace_array *tr;
	129	+ const void __user *fp;
	130	+ int is_user;
	131	+ int i;
	132	+
	133	+ if (!regs)
	134	+ return;
	135	+
	136	+ tr = sysprof_trace;
	137	+ data = tr->data[cpu];
	138	+ is_user = user_mode(regs);
	139	+
	140	+ if (!current \|\| current->pid == 0)
	141	+ return;
	142	+
	143	+ if (is_user && current->state != TASK_RUNNING)
	144	+ return;
	145	+
	146	+ __trace_special(tr, data, 0, 0, current->pid);
	147	+
	148	+ if (!is_user)
	149	+ i = trace_kernel(regs, tr, data);
	150	+ else
	151	+ i = 0;
	152	+
	153	+ /*
	154	+ * Trace user stack if we are not a kernel thread
	155	+ */
	156	+ if (current->mm && i < sample_max_depth) {
	157	+ regs = (struct pt_regs *)current->thread.sp0 - 1;
	158	+
	159	+ fp = (void __user *)regs->bp;
	160	+
	161	+ __trace_special(tr, data, 2, regs->ip, 0);
	162	+
	163	+ while (i < sample_max_depth) {
	164	+ frame.next_fp = 0;
	165	+ frame.return_address = 0;
	166	+ if (!copy_stack_frame(fp, &frame))
	167	+ break;
	168	+ if ((unsigned long)fp < regs->sp)
	169	+ break;
	170	+
	171	+ __trace_special(tr, data, 2, frame.return_address,
	172	+ (unsigned long)fp);
	173	+ fp = frame.next_fp;
	174	+
	175	+ i++;
	176	+ }
	177	+
	178	+ }
	179	+
	180	+ /*
	181	+ * Special trace entry if we overflow the max depth:
	182	+ */
	183	+ if (i == sample_max_depth)
	184	+ __trace_special(tr, data, -1, -1, -1);
	185	+
	186	+ __trace_special(tr, data, 3, current->pid, i);
	187	+}
	188	+
	189	+static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
	190	+{
	191	+ /* trace here */
	192	+ timer_notify(get_irq_regs(), smp_processor_id());
	193	+
	194	+ hrtimer_forward_now(hrtimer, ns_to_ktime(sample_period));
	195	+
	196	+ return HRTIMER_RESTART;
	197	+}
	198	+
	199	+static void start_stack_timer(int cpu)
	200	+{
	201	+ struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
	202	+
	203	+ hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	204	+ hrtimer->function = stack_trace_timer_fn;
	205	+ hrtimer->cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
	206	+
	207	+ hrtimer_start(hrtimer, ns_to_ktime(sample_period), HRTIMER_MODE_REL);
	208	+}
	209	+
	210	+static void start_stack_timers(void)
	211	+{
	212	+ cpumask_t saved_mask = current->cpus_allowed;
	213	+ int cpu;
	214	+
	215	+ for_each_online_cpu(cpu) {
	216	+ set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
	217	+ start_stack_timer(cpu);
	218	+ }
	219	+ set_cpus_allowed_ptr(current, &saved_mask);
	220	+}
	221	+
	222	+static void stop_stack_timer(int cpu)
	223	+{
	224	+ struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
	225	+
	226	+ hrtimer_cancel(hrtimer);
	227	+}
	228	+
	229	+static void stop_stack_timers(void)
	230	+{
	231	+ int cpu;
	232	+
	233	+ for_each_online_cpu(cpu)
	234	+ stop_stack_timer(cpu);
	235	+}
	236	+
	237	+static void stack_reset(struct trace_array *tr)
	238	+{
	239	+ int cpu;
	240	+
	241	+ tr->time_start = ftrace_now(tr->cpu);
	242	+
	243	+ for_each_online_cpu(cpu)
	244	+ tracing_reset(tr->data[cpu]);
	245	+}
	246	+
	247	+static void start_stack_trace(struct trace_array *tr)
	248	+{
	249	+ mutex_lock(&sample_timer_lock);
	250	+ stack_reset(tr);
	251	+ start_stack_timers();
	252	+ tracer_enabled = 1;
	253	+ mutex_unlock(&sample_timer_lock);
	254	+}
	255	+
	256	+static void stop_stack_trace(struct trace_array *tr)
	257	+{
	258	+ mutex_lock(&sample_timer_lock);
	259	+ stop_stack_timers();
	260	+ tracer_enabled = 0;
	261	+ mutex_unlock(&sample_timer_lock);
	262	+}
	263	+
	264	+static void stack_trace_init(struct trace_array *tr)
	265	+{
	266	+ sysprof_trace = tr;
	267	+
	268	+ if (tr->ctrl)
	269	+ start_stack_trace(tr);
	270	+}
	271	+
	272	+static void stack_trace_reset(struct trace_array *tr)
	273	+{
	274	+ if (tr->ctrl)
	275	+ stop_stack_trace(tr);
	276	+}
	277	+
	278	+static void stack_trace_ctrl_update(struct trace_array *tr)
	279	+{
	280	+ /* When starting a new trace, reset the buffers */
	281	+ if (tr->ctrl)
	282	+ start_stack_trace(tr);
	283	+ else
	284	+ stop_stack_trace(tr);
	285	+}
	286	+
	287	+static struct tracer stack_trace __read_mostly =
	288	+{
	289	+ .name = "sysprof",
	290	+ .init = stack_trace_init,
	291	+ .reset = stack_trace_reset,
	292	+ .ctrl_update = stack_trace_ctrl_update,
	293	+#ifdef CONFIG_FTRACE_SELFTEST
	294	+ .selftest = trace_selftest_startup_sysprof,
	295	+#endif
	296	+};
	297	+
	298	+__init static int init_stack_trace(void)
	299	+{
	300	+ return register_tracer(&stack_trace);
	301	+}
	302	+device_initcall(init_stack_trace);
	303	+
	304	+#define MAX_LONG_DIGITS 22
	305	+
	306	+static ssize_t
	307	+sysprof_sample_read(struct file filp, char __user ubuf,
	308	+ size_t cnt, loff_t *ppos)
	309	+{
	310	+ char buf[MAX_LONG_DIGITS];
	311	+ int r;
	312	+
	313	+ r = sprintf(buf, "%ld\n", nsecs_to_usecs(sample_period));
	314	+
	315	+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
	316	+}
	317	+
	318	+static ssize_t
	319	+sysprof_sample_write(struct file filp, const char __user ubuf,
	320	+ size_t cnt, loff_t *ppos)
	321	+{
	322	+ char buf[MAX_LONG_DIGITS];
	323	+ unsigned long val;
	324	+
	325	+ if (cnt > MAX_LONG_DIGITS-1)
	326	+ cnt = MAX_LONG_DIGITS-1;
	327	+
	328	+ if (copy_from_user(&buf, ubuf, cnt))
	329	+ return -EFAULT;
	330	+
	331	+ buf[cnt] = 0;
	332	+
	333	+ val = simple_strtoul(buf, NULL, 10);
	334	+ /*
	335	+ * Enforce a minimum sample period of 100 usecs:
	336	+ */
	337	+ if (val < 100)
	338	+ val = 100;
	339	+
	340	+ mutex_lock(&sample_timer_lock);
	341	+ stop_stack_timers();
	342	+ sample_period = val * 1000;
	343	+ start_stack_timers();
	344	+ mutex_unlock(&sample_timer_lock);
	345	+
	346	+ return cnt;
	347	+}
	348	+
	349	+static struct file_operations sysprof_sample_fops = {
	350	+ .read = sysprof_sample_read,
	351	+ .write = sysprof_sample_write,
	352	+};
	353	+
	354	+void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
	355	+{
	356	+ struct dentry *entry;
	357	+
	358	+ entry = debugfs_create_file("sysprof_sample_period", 0644,
	359	+ d_tracer, NULL, &sysprof_sample_fops);
	360	+ if (entry)
	361	+ return;
	362	+ pr_warning("Could not create debugfs 'dyn_ftrace_total_info' entry\n");
	363	+}