20 files changed, 739 insertions, 198 deletions

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 8a0c2f221e6b..53869bef6102 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -368,6 +368,7 @@ struct ftrace_ret_stack {
 	unsigned long ret;
 	unsigned long func;
 	unsigned long long calltime;
+	unsigned long long subtime;
 };
 
 /*
@@ -379,8 +380,6 @@ extern void return_to_handler(void);
 
 extern int
 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth);
-extern void
-ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret);
 
 /*
  * Sometimes we don't want to trace a function with the function
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 2246141bda4d..23b96ebbf893 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -104,6 +104,7 @@ config FUNCTION_GRAPH_TRACER
 	  the return value. This is done by setting the current return 
 	  address on the current task structure into a stack of calls.
 
+
 config IRQSOFF_TRACER
 	bool "Interrupts-off Latency Tracer"
 	default n
@@ -375,6 +376,20 @@ config DYNAMIC_FTRACE
 	 were made. If so, it runs stop_machine (stops all CPUS)
 	 and modifies the code to jump over the call to ftrace.
 
+config FUNCTION_PROFILER
+	bool "Kernel function profiler"
+	depends on FUNCTION_TRACER
+	default n
+	help
+	 This option enables the kernel function profiler. A file is created
+	 in debugfs called function_profile_enabled which defaults to zero.
+	 When a 1 is echoed into this file profiling begins, and when a
+	 zero is entered, profiling stops. A file in the trace_stats
+	 directory called functions, that show the list of functions that
+	 have been hit and their counters.
+
+	 If in doubt, say N
+
 config FTRACE_MCOUNT_RECORD
 	def_bool y
 	depends on DYNAMIC_FTRACE
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index f1ed080406c3..8e6a0b5c9940 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -33,7 +33,8 @@
 
 #include <asm/ftrace.h>
 
-#include "trace.h"
+#include "trace_output.h"
+#include "trace_stat.h"
 
 #define FTRACE_WARN_ON(cond)			\
 	do {					\
@@ -68,7 +69,7 @@ static DEFINE_MUTEX(ftrace_lock);
 
 static struct ftrace_ops ftrace_list_end __read_mostly =
 {
-	.func = ftrace_stub,
+	.func		= ftrace_stub,
 };
 
 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
@@ -240,6 +241,576 @@ static void ftrace_update_pid_func(void)
 #endif
 }
 
+#ifdef CONFIG_FUNCTION_PROFILER
+struct ftrace_profile {
+	struct hlist_node		node;
+	unsigned long			ip;
+	unsigned long			counter;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	unsigned long long		time;
+#endif
+};
+
+struct ftrace_profile_page {
+	struct ftrace_profile_page	*next;
+	unsigned long			index;
+	struct ftrace_profile		records[];
+};
+
+struct ftrace_profile_stat {
+	atomic_t			disabled;
+	struct hlist_head		*hash;
+	struct ftrace_profile_page	*pages;
+	struct ftrace_profile_page	*start;
+	struct tracer_stat		stat;
+};
+
+#define PROFILE_RECORDS_SIZE						\
+	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
+
+#define PROFILES_PER_PAGE					\
+	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
+
+static int ftrace_profile_bits __read_mostly;
+static int ftrace_profile_enabled __read_mostly;
+
+/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
+static DEFINE_MUTEX(ftrace_profile_lock);
+
+static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
+
+#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
+
+static void *
+function_stat_next(void *v, int idx)
+{
+	struct ftrace_profile *rec = v;
+	struct ftrace_profile_page *pg;
+
+	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
+
+ again:
+	rec++;
+	if ((void *)rec >= (void *)&pg->records[pg->index]) {
+		pg = pg->next;
+		if (!pg)
+			return NULL;
+		rec = &pg->records[0];
+		if (!rec->counter)
+			goto again;
+	}
+
+	return rec;
+}
+
+static void *function_stat_start(struct tracer_stat *trace)
+{
+	struct ftrace_profile_stat *stat =
+		container_of(trace, struct ftrace_profile_stat, stat);
+
+	if (!stat || !stat->start)
+		return NULL;
+
+	return function_stat_next(&stat->start->records[0], 0);
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+/* function graph compares on total time */
+static int function_stat_cmp(void *p1, void *p2)
+{
+	struct ftrace_profile *a = p1;
+	struct ftrace_profile *b = p2;
+
+	if (a->time < b->time)
+		return -1;
+	if (a->time > b->time)
+		return 1;
+	else
+		return 0;
+}
+#else
+/* not function graph compares against hits */
+static int function_stat_cmp(void *p1, void *p2)
+{
+	struct ftrace_profile *a = p1;
+	struct ftrace_profile *b = p2;
+
+	if (a->counter < b->counter)
+		return -1;
+	if (a->counter > b->counter)
+		return 1;
+	else
+		return 0;
+}
+#endif
+
+static int function_stat_headers(struct seq_file *m)
+{
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	seq_printf(m, "  Function                               "
+		   "Hit    Time            Avg\n"
+		      "  --------                               "
+		   "---    ----            ---\n");
+#else
+	seq_printf(m, "  Function                               Hit\n"
+		      "  --------                               ---\n");
+#endif
+	return 0;
+}
+
+static int function_stat_show(struct seq_file *m, void *v)
+{
+	struct ftrace_profile *rec = v;
+	char str[KSYM_SYMBOL_LEN];
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	static DEFINE_MUTEX(mutex);
+	static struct trace_seq s;
+	unsigned long long avg;
+#endif
+
+	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
+	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	seq_printf(m, "    ");
+	avg = rec->time;
+	do_div(avg, rec->counter);
+
+	mutex_lock(&mutex);
+	trace_seq_init(&s);
+	trace_print_graph_duration(rec->time, &s);
+	trace_seq_puts(&s, "    ");
+	trace_print_graph_duration(avg, &s);
+	trace_print_seq(m, &s);
+	mutex_unlock(&mutex);
+#endif
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
+{
+	struct ftrace_profile_page *pg;
+
+	pg = stat->pages = stat->start;
+
+	while (pg) {
+		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
+		pg->index = 0;
+		pg = pg->next;
+	}
+
+	memset(stat->hash, 0,
+	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
+}
+
+int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
+{
+	struct ftrace_profile_page *pg;
+	int functions;
+	int pages;
+	int i;
+
+	/* If we already allocated, do nothing */
+	if (stat->pages)
+		return 0;
+
+	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
+	if (!stat->pages)
+		return -ENOMEM;
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	functions = ftrace_update_tot_cnt;
+#else
+	/*
+	 * We do not know the number of functions that exist because
+	 * dynamic tracing is what counts them. With past experience
+	 * we have around 20K functions. That should be more than enough.
+	 * It is highly unlikely we will execute every function in
+	 * the kernel.
+	 */
+	functions = 20000;
+#endif
+
+	pg = stat->start = stat->pages;
+
+	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
+
+	for (i = 0; i < pages; i++) {
+		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!pg->next)
+			goto out_free;
+		pg = pg->next;
+	}
+
+	return 0;
+
+ out_free:
+	pg = stat->start;
+	while (pg) {
+		unsigned long tmp = (unsigned long)pg;
+
+		pg = pg->next;
+		free_page(tmp);
+	}
+
+	free_page((unsigned long)stat->pages);
+	stat->pages = NULL;
+	stat->start = NULL;
+
+	return -ENOMEM;
+}
+
+static int ftrace_profile_init_cpu(int cpu)
+{
+	struct ftrace_profile_stat *stat;
+	int size;
+
+	stat = &per_cpu(ftrace_profile_stats, cpu);
+
+	if (stat->hash) {
+		/* If the profile is already created, simply reset it */
+		ftrace_profile_reset(stat);
+		return 0;
+	}
+
+	/*
+	 * We are profiling all functions, but usually only a few thousand
+	 * functions are hit. We'll make a hash of 1024 items.
+	 */
+	size = FTRACE_PROFILE_HASH_SIZE;
+
+	stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
+
+	if (!stat->hash)
+		return -ENOMEM;
+
+	if (!ftrace_profile_bits) {
+		size--;
+
+		for (; size; size >>= 1)
+			ftrace_profile_bits++;
+	}
+
+	/* Preallocate the function profiling pages */
+	if (ftrace_profile_pages_init(stat) < 0) {
+		kfree(stat->hash);
+		stat->hash = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int ftrace_profile_init(void)
+{
+	int cpu;
+	int ret = 0;
+
+	for_each_online_cpu(cpu) {
+		ret = ftrace_profile_init_cpu(cpu);
+		if (ret)
+			break;
+	}
+
+	return ret;
+}
+
+/* interrupts must be disabled */
+static struct ftrace_profile *
+ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
+{
+	struct ftrace_profile *rec;
+	struct hlist_head *hhd;
+	struct hlist_node *n;
+	unsigned long key;
+
+	key = hash_long(ip, ftrace_profile_bits);
+	hhd = &stat->hash[key];
+
+	if (hlist_empty(hhd))
+		return NULL;
+
+	hlist_for_each_entry_rcu(rec, n, hhd, node) {
+		if (rec->ip == ip)
+			return rec;
+	}
+
+	return NULL;
+}
+
+static void ftrace_add_profile(struct ftrace_profile_stat *stat,
+			       struct ftrace_profile *rec)
+{
+	unsigned long key;
+
+	key = hash_long(rec->ip, ftrace_profile_bits);
+	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
+}
+
+/*
+ * The memory is already allocated, this simply finds a new record to use.
+ */
+static struct ftrace_profile *
+ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
+{
+	struct ftrace_profile *rec = NULL;
+
+	/* prevent recursion (from NMIs) */
+	if (atomic_inc_return(&stat->disabled) != 1)
+		goto out;
+
+	/*
+	 * Try to find the function again since an NMI
+	 * could have added it
+	 */
+	rec = ftrace_find_profiled_func(stat, ip);
+	if (rec)
+		goto out;
+
+	if (stat->pages->index == PROFILES_PER_PAGE) {
+		if (!stat->pages->next)
+			goto out;
+		stat->pages = stat->pages->next;
+	}
+
+	rec = &stat->pages->records[stat->pages->index++];
+	rec->ip = ip;
+	ftrace_add_profile(stat, rec);
+
+ out:
+	atomic_dec(&stat->disabled);
+
+	return rec;
+}
+
+static void
+function_profile_call(unsigned long ip, unsigned long parent_ip)
+{
+	struct ftrace_profile_stat *stat;
+	struct ftrace_profile *rec;
+	unsigned long flags;
+
+	if (!ftrace_profile_enabled)
+		return;
+
+	local_irq_save(flags);
+
+	stat = &__get_cpu_var(ftrace_profile_stats);
+	if (!stat->hash)
+		goto out;
+
+	rec = ftrace_find_profiled_func(stat, ip);
+	if (!rec) {
+		rec = ftrace_profile_alloc(stat, ip);
+		if (!rec)
+			goto out;
+	}
+
+	rec->counter++;
+ out:
+	local_irq_restore(flags);
+}
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+static int profile_graph_entry(struct ftrace_graph_ent *trace)
+{
+	function_profile_call(trace->func, 0);
+	return 1;
+}
+
+static void profile_graph_return(struct ftrace_graph_ret *trace)
+{
+	struct ftrace_profile_stat *stat;
+	unsigned long long calltime;
+	struct ftrace_profile *rec;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	stat = &__get_cpu_var(ftrace_profile_stats);
+	if (!stat->hash)
+		goto out;
+
+	calltime = trace->rettime - trace->calltime;
+
+	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
+		int index;
+
+		index = trace->depth;
+
+		/* Append this call time to the parent time to subtract */
+		if (index)
+			current->ret_stack[index - 1].subtime += calltime;
+
+		if (current->ret_stack[index].subtime < calltime)
+			calltime -= current->ret_stack[index].subtime;
+		else
+			calltime = 0;
+	}
+
+	rec = ftrace_find_profiled_func(stat, trace->func);
+	if (rec)
+		rec->time += calltime;
+
+ out:
+	local_irq_restore(flags);
+}
+
+static int register_ftrace_profiler(void)
+{
+	return register_ftrace_graph(&profile_graph_return,
+				     &profile_graph_entry);
+}
+
+static void unregister_ftrace_profiler(void)
+{
+	unregister_ftrace_graph();
+}
+#else
+static struct ftrace_ops ftrace_profile_ops __read_mostly =
+{
+	.func		= function_profile_call,
+};
+
+static int register_ftrace_profiler(void)
+{
+	return register_ftrace_function(&ftrace_profile_ops);
+}
+
+static void unregister_ftrace_profiler(void)
+{
+	unregister_ftrace_function(&ftrace_profile_ops);
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
+static ssize_t
+ftrace_profile_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	char buf[64];		/* big enough to hold a number */
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	val = !!val;
+
+	mutex_lock(&ftrace_profile_lock);
+	if (ftrace_profile_enabled ^ val) {
+		if (val) {
+			ret = ftrace_profile_init();
+			if (ret < 0) {
+				cnt = ret;
+				goto out;
+			}
+
+			ret = register_ftrace_profiler();
+			if (ret < 0) {
+				cnt = ret;
+				goto out;
+			}
+			ftrace_profile_enabled = 1;
+		} else {
+			ftrace_profile_enabled = 0;
+			unregister_ftrace_profiler();
+		}
+	}
+ out:
+	mutex_unlock(&ftrace_profile_lock);
+
+	filp->f_pos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+ftrace_profile_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	char buf[64];		/* big enough to hold a number */
+	int r;
+
+	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static const struct file_operations ftrace_profile_fops = {
+	.open		= tracing_open_generic,
+	.read		= ftrace_profile_read,
+	.write		= ftrace_profile_write,
+};
+
+/* used to initialize the real stat files */
+static struct tracer_stat function_stats __initdata = {
+	.name		= "functions",
+	.stat_start	= function_stat_start,
+	.stat_next	= function_stat_next,
+	.stat_cmp	= function_stat_cmp,
+	.stat_headers	= function_stat_headers,
+	.stat_show	= function_stat_show
+};
+
+static void ftrace_profile_debugfs(struct dentry *d_tracer)
+{
+	struct ftrace_profile_stat *stat;
+	struct dentry *entry;
+	char *name;
+	int ret;
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		stat = &per_cpu(ftrace_profile_stats, cpu);
+
+		/* allocate enough for function name + cpu number */
+		name = kmalloc(32, GFP_KERNEL);
+		if (!name) {
+			/*
+			 * The files created are permanent, if something happens
+			 * we still do not free memory.
+			 */
+			kfree(stat);
+			WARN(1,
+			     "Could not allocate stat file for cpu %d\n",
+			     cpu);
+			return;
+		}
+		stat->stat = function_stats;
+		snprintf(name, 32, "function%d", cpu);
+		stat->stat.name = name;
+		ret = register_stat_tracer(&stat->stat);
+		if (ret) {
+			WARN(1,
+			     "Could not register function stat for cpu %d\n",
+			     cpu);
+			kfree(name);
+			return;
+		}
+	}
+
+	entry = debugfs_create_file("function_profile_enabled", 0644,
+				    d_tracer, NULL, &ftrace_profile_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'function_profile_enabled' entry\n");
+}
+
+#else /* CONFIG_FUNCTION_PROFILER */
+static void ftrace_profile_debugfs(struct dentry *d_tracer)
+{
+}
+#endif /* CONFIG_FUNCTION_PROFILER */
+
 /* set when tracing only a pid */
 struct pid *ftrace_pid_trace;
 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
@@ -261,7 +832,6 @@ struct ftrace_func_probe {
 	struct rcu_head		rcu;
 };
 
-
 enum {
 	FTRACE_ENABLE_CALLS		= (1 << 0),
 	FTRACE_DISABLE_CALLS		= (1 << 1),
@@ -1408,7 +1978,7 @@ function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
 
 static struct ftrace_ops trace_probe_ops __read_mostly =
 {
-	.func = function_trace_probe_call,
+	.func		= function_trace_probe_call,
 };
 
 static int ftrace_probe_registered;
@@ -2128,38 +2698,23 @@ static const struct file_operations ftrace_graph_fops = {
 
 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 {
-	struct dentry *entry;
 
-	entry = debugfs_create_file("available_filter_functions", 0444,
-				    d_tracer, NULL, &ftrace_avail_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'available_filter_functions' entry\n");
+	trace_create_file("available_filter_functions", 0444,
+			d_tracer, NULL, &ftrace_avail_fops);
 
-	entry = debugfs_create_file("failures", 0444,
-				    d_tracer, NULL, &ftrace_failures_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'failures' entry\n");
+	trace_create_file("failures", 0444,
+			d_tracer, NULL, &ftrace_failures_fops);
 
-	entry = debugfs_create_file("set_ftrace_filter", 0644, d_tracer,
-				    NULL, &ftrace_filter_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'set_ftrace_filter' entry\n");
+	trace_create_file("set_ftrace_filter", 0644, d_tracer,
+			NULL, &ftrace_filter_fops);
 
-	entry = debugfs_create_file("set_ftrace_notrace", 0644, d_tracer,
+	trace_create_file("set_ftrace_notrace", 0644, d_tracer,
 				    NULL, &ftrace_notrace_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'set_ftrace_notrace' entry\n");
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	entry = debugfs_create_file("set_graph_function", 0444, d_tracer,
+	trace_create_file("set_graph_function", 0444, d_tracer,
 				    NULL,
 				    &ftrace_graph_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'set_graph_function' entry\n");
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
 	return 0;
@@ -2417,7 +2972,6 @@ static const struct file_operations ftrace_pid_fops = {
 static __init int ftrace_init_debugfs(void)
 {
 	struct dentry *d_tracer;
-	struct dentry *entry;
 
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
@@ -2425,11 +2979,11 @@ static __init int ftrace_init_debugfs(void)
 
 	ftrace_init_dyn_debugfs(d_tracer);
 
-	entry = debugfs_create_file("set_ftrace_pid", 0644, d_tracer,
-				    NULL, &ftrace_pid_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'set_ftrace_pid' entry\n");
+	trace_create_file("set_ftrace_pid", 0644, d_tracer,
+			    NULL, &ftrace_pid_fops);
+
+	ftrace_profile_debugfs(d_tracer);
+
 	return 0;
 }
 fs_initcall(ftrace_init_debugfs);
@@ -2538,7 +3092,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
-static atomic_t ftrace_graph_active;
+static int ftrace_graph_active;
 static struct notifier_block ftrace_suspend_notifier;
 
 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
@@ -2690,7 +3244,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 	mutex_lock(&ftrace_lock);
 
 	/* we currently allow only one tracer registered at a time */
-	if (atomic_read(&ftrace_graph_active)) {
+	if (ftrace_graph_active) {
 		ret = -EBUSY;
 		goto out;
 	}
@@ -2698,10 +3252,10 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
 	register_pm_notifier(&ftrace_suspend_notifier);
 
-	atomic_inc(&ftrace_graph_active);
+	ftrace_graph_active++;
 	ret = start_graph_tracing();
 	if (ret) {
-		atomic_dec(&ftrace_graph_active);
+		ftrace_graph_active--;
 		goto out;
 	}
 
@@ -2719,10 +3273,10 @@ void unregister_ftrace_graph(void)
 {
 	mutex_lock(&ftrace_lock);
 
-	if (!unlikely(atomic_read(&ftrace_graph_active)))
+	if (unlikely(!ftrace_graph_active))
 		goto out;
 
-	atomic_dec(&ftrace_graph_active);
+	ftrace_graph_active--;
 	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
 	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
 	ftrace_graph_entry = ftrace_graph_entry_stub;
@@ -2736,7 +3290,7 @@ void unregister_ftrace_graph(void)
 /* Allocate a return stack for newly created task */
 void ftrace_graph_init_task(struct task_struct *t)
 {
-	if (atomic_read(&ftrace_graph_active)) {
+	if (ftrace_graph_active) {
 		t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
 				* sizeof(struct ftrace_ret_stack),
 				GFP_KERNEL);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 960cbf44c844..74a11808c282 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2845,14 +2845,11 @@ static const struct file_operations rb_simple_fops = {
 static __init int rb_init_debugfs(void)
 {
 	struct dentry *d_tracer;
-	struct dentry *entry;
 
 	d_tracer = tracing_init_dentry();
 
-	entry = debugfs_create_file("tracing_on", 0644, d_tracer,
-				    &ring_buffer_flags, &rb_simple_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'tracing_on' entry\n");
+	trace_create_file("tracing_on", 0644, d_tracer,
+			    &ring_buffer_flags, &rb_simple_fops);
 
 	return 0;
 }
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1ce5dc6372b8..4865459f609f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -255,7 +255,8 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
 
 /* trace_flags holds trace_options default values */
 unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
-	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME;
+	TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | TRACE_ITER_SLEEP_TIME |
+	TRACE_ITER_GRAPH_TIME;
 
 /**
  * trace_wake_up - wake up tasks waiting for trace input
@@ -317,6 +318,7 @@ static const char *trace_options[] = {
 	"latency-format",
 	"global-clock",
 	"sleep-time",
+	"graph-time",
 	NULL
 };
 
@@ -402,17 +404,6 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 	return cnt;
 }
 
-static void
-trace_print_seq(struct seq_file *m, struct trace_seq *s)
-{
-	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
-
-	s->buffer[len] = 0;
-	seq_puts(m, s->buffer);
-
-	trace_seq_init(s);
-}
-
 /**
  * update_max_tr - snapshot all trace buffers from global_trace to max_tr
  * @tr: tracer
@@ -3596,7 +3587,7 @@ struct dentry *tracing_dentry_percpu(void)
 static void tracing_init_debugfs_percpu(long cpu)
 {
 	struct dentry *d_percpu = tracing_dentry_percpu();
-	struct dentry *entry, *d_cpu;
+	struct dentry *d_cpu;
 	/* strlen(cpu) + MAX(log10(cpu)) + '\0' */
 	char cpu_dir[7];
 
@@ -3611,21 +3602,15 @@ static void tracing_init_debugfs_percpu(long cpu)
 	}
 
 	/* per cpu trace_pipe */
-	entry = debugfs_create_file("trace_pipe", 0444, d_cpu,
-				(void *) cpu, &tracing_pipe_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'trace_pipe' entry\n");
+	trace_create_file("trace_pipe", 0444, d_cpu,
+			(void *) cpu, &tracing_pipe_fops);
 
 	/* per cpu trace */
-	entry = debugfs_create_file("trace", 0644, d_cpu,
-				(void *) cpu, &tracing_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'trace' entry\n");
+	trace_create_file("trace", 0644, d_cpu,
+			(void *) cpu, &tracing_fops);
 
-	entry = debugfs_create_file("trace_pipe_raw", 0444, d_cpu,
-				    (void *) cpu, &tracing_buffers_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'trace_pipe_raw' entry\n");
+	trace_create_file("trace_pipe_raw", 0444, d_cpu,
+			(void *) cpu, &tracing_buffers_fops);
 }
 
 #ifdef CONFIG_FTRACE_SELFTEST
@@ -3781,6 +3766,22 @@ static const struct file_operations trace_options_core_fops = {
 	.write = trace_options_core_write,
 };
 
+struct dentry *trace_create_file(const char *name,
+				 mode_t mode,
+				 struct dentry *parent,
+				 void *data,
+				 const struct file_operations *fops)
+{
+	struct dentry *ret;
+
+	ret = debugfs_create_file(name, mode, parent, data, fops);
+	if (!ret)
+		pr_warning("Could not create debugfs '%s' entry\n", name);
+
+	return ret;
+}
+
+
 static struct dentry *trace_options_init_dentry(void)
 {
 	struct dentry *d_tracer;
@@ -3808,7 +3809,6 @@ create_trace_option_file(struct trace_option_dentry *topt,
 			 struct tracer_opt *opt)
 {
 	struct dentry *t_options;
-	struct dentry *entry;
 
 	t_options = trace_options_init_dentry();
 	if (!t_options)
@@ -3817,11 +3817,9 @@ create_trace_option_file(struct trace_option_dentry *topt,
 	topt->flags = flags;
 	topt->opt = opt;
 
-	entry = debugfs_create_file(opt->name, 0644, t_options, topt,
+	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
 				    &trace_options_fops);
 
-	topt->entry = entry;
-
 }
 
 static struct trace_option_dentry *
@@ -3876,123 +3874,81 @@ static struct dentry *
 create_trace_option_core_file(const char *option, long index)
 {
 	struct dentry *t_options;
-	struct dentry *entry;
 
 	t_options = trace_options_init_dentry();
 	if (!t_options)
 		return NULL;
 
-	entry = debugfs_create_file(option, 0644, t_options, (void *)index,
+	return trace_create_file(option, 0644, t_options, (void *)index,
 				    &trace_options_core_fops);
-
-	return entry;
 }
 
 static __init void create_trace_options_dir(void)
 {
 	struct dentry *t_options;
-	struct dentry *entry;
 	int i;
 
 	t_options = trace_options_init_dentry();
 	if (!t_options)
 		return;
 
-	for (i = 0; trace_options[i]; i++) {
-		entry = create_trace_option_core_file(trace_options[i], i);
-		if (!entry)
-			pr_warning("Could not create debugfs %s entry\n",
-				   trace_options[i]);
-	}
+	for (i = 0; trace_options[i]; i++)
+		create_trace_option_core_file(trace_options[i], i);
 }
 
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
-	struct dentry *entry;
 	int cpu;
 
 	d_tracer = tracing_init_dentry();
 
-	entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
-				    &global_trace, &tracing_ctrl_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
+	trace_create_file("tracing_enabled", 0644, d_tracer,
+			&global_trace, &tracing_ctrl_fops);
 
-	entry = debugfs_create_file("trace_options", 0644, d_tracer,
-				    NULL, &tracing_iter_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'trace_options' entry\n");
+	trace_create_file("trace_options", 0644, d_tracer,
+			NULL, &tracing_iter_fops);
 
-	create_trace_options_dir();
+	trace_create_file("tracing_cpumask", 0644, d_tracer,
+			NULL, &tracing_cpumask_fops);
+
+	trace_create_file("trace", 0644, d_tracer,
+			(void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
+
+	trace_create_file("available_tracers", 0444, d_tracer,
+			&global_trace, &show_traces_fops);
+
+	trace_create_file("current_tracer", 0444, d_tracer,
+			&global_trace, &set_tracer_fops);
 
-	entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
-				    NULL, &tracing_cpumask_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
-
-	entry = debugfs_create_file("trace", 0644, d_tracer,
-				 (void *) TRACE_PIPE_ALL_CPU, &tracing_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'trace' entry\n");
-
-	entry = debugfs_create_file("available_tracers", 0444, d_tracer,
-				    &global_trace, &show_traces_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'available_tracers' entry\n");
-
-	entry = debugfs_create_file("current_tracer", 0444, d_tracer,
-				    &global_trace, &set_tracer_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'current_tracer' entry\n");
-
-	entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
-				    &tracing_max_latency,
-				    &tracing_max_lat_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'tracing_max_latency' entry\n");
-
-	entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
-				    &tracing_thresh, &tracing_max_lat_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'tracing_thresh' entry\n");
-	entry = debugfs_create_file("README", 0644, d_tracer,
-				    NULL, &tracing_readme_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'README' entry\n");
-
-	entry = debugfs_create_file("trace_pipe", 0444, d_tracer,
+	trace_create_file("tracing_max_latency", 0644, d_tracer,
+			&tracing_max_latency, &tracing_max_lat_fops);
+
+	trace_create_file("tracing_thresh", 0644, d_tracer,
+			&tracing_thresh, &tracing_max_lat_fops);
+
+	trace_create_file("README", 0644, d_tracer,
+			NULL, &tracing_readme_fops);
+
+	trace_create_file("trace_pipe", 0444, d_tracer,
 			(void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'trace_pipe' entry\n");
-
-	entry = debugfs_create_file("buffer_size_kb", 0644, d_tracer,
-				    &global_trace, &tracing_entries_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'buffer_size_kb' entry\n");
-
-	entry = debugfs_create_file("trace_marker", 0220, d_tracer,
-				    NULL, &tracing_mark_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'trace_marker' entry\n");
+
+	trace_create_file("buffer_size_kb", 0644, d_tracer,
+			&global_trace, &tracing_entries_fops);
+
+	trace_create_file("trace_marker", 0220, d_tracer,
+			NULL, &tracing_mark_fops);
 
 #ifdef CONFIG_DYNAMIC_FTRACE
-	entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
-				    &ftrace_update_tot_cnt,
-				    &tracing_dyn_info_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'dyn_ftrace_total_info' entry\n");
+	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
+			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
 #endif
 #ifdef CONFIG_SYSPROF_TRACER
 	init_tracer_sysprof_debugfs(d_tracer);
 #endif
 
+	create_trace_options_dir();
+
 	for_each_tracing_cpu(cpu)
 		tracing_init_debugfs_percpu(cpu);
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e685ac2b2ba1..f76a8f8689d4 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -470,6 +470,12 @@ void trace_wake_up(void);
 void tracing_reset(struct trace_array *tr, int cpu);
 void tracing_reset_online_cpus(struct trace_array *tr);
 int tracing_open_generic(struct inode *inode, struct file *filp);
+struct dentry *trace_create_file(const char *name,
+				 mode_t mode,
+				 struct dentry *parent,
+				 void *data,
+				 const struct file_operations *fops);
+
 struct dentry *tracing_init_dentry(void);
 void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
 
@@ -613,6 +619,8 @@ extern unsigned long trace_flags;
 /* 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);
+extern enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s);
 
 #ifdef CONFIG_DYNAMIC_FTRACE
 /* TODO: make this variable */
@@ -644,7 +652,6 @@ static inline int ftrace_graph_addr(unsigned long addr)
 	return 1;
 }
 #endif /* CONFIG_DYNAMIC_FTRACE */
-
 #else /* CONFIG_FUNCTION_GRAPH_TRACER */
 static inline enum print_line_t
 print_graph_function(struct trace_iterator *iter)
@@ -692,6 +699,7 @@ enum trace_iterator_flags {
 	TRACE_ITER_LATENCY_FMT		= 0x40000,
 	TRACE_ITER_GLOBAL_CLK		= 0x80000,
 	TRACE_ITER_SLEEP_TIME		= 0x100000,
+	TRACE_ITER_GRAPH_TIME		= 0x200000,
 };
 
 /*
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index 7a30fc4c3642..a29ef23ffb47 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -9,6 +9,7 @@
 #include <linux/debugfs.h>
 #include <linux/ftrace.h>
 #include <linux/kallsyms.h>
+#include <linux/time.h>
 
 #include "trace.h"
 #include "trace_output.h"
@@ -67,7 +68,7 @@ initcall_call_print_line(struct trace_iterator *iter)
 	trace_assign_type(field, entry);
 	call = &field->boot_call;
 	ts = iter->ts;
-	nsec_rem = do_div(ts, 1000000000);
+	nsec_rem = do_div(ts, NSEC_PER_SEC);
 
 	ret = trace_seq_printf(s, "[%5ld.%09ld] calling  %s @ %i\n",
 			(unsigned long)ts, nsec_rem, call->func, call->caller);
@@ -92,7 +93,7 @@ initcall_ret_print_line(struct trace_iterator *iter)
 	trace_assign_type(field, entry);
 	init_ret = &field->boot_ret;
 	ts = iter->ts;
-	nsec_rem = do_div(ts, 1000000000);
+	nsec_rem = do_div(ts, NSEC_PER_SEC);
 
 	ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
 			"returned %d after %llu msecs\n",
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index ad8c22efff41..e6e32912ffb8 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -263,7 +263,7 @@ static int branch_stat_show(struct seq_file *m, void *v)
 	return 0;
 }
 
-static void *annotated_branch_stat_start(void)
+static void *annotated_branch_stat_start(struct tracer_stat *trace)
 {
 	return __start_annotated_branch_profile;
 }
@@ -338,7 +338,7 @@ static int all_branch_stat_headers(struct seq_file *m)
 	return 0;
 }
 
-static void *all_branch_stat_start(void)
+static void *all_branch_stat_start(struct tracer_stat *trace)
 {
 	return __start_branch_profile;
 }
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 22cba9970776..199de9c74229 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -28,4 +28,3 @@ void ftrace_profile_disable(int event_id)
 			return event->profile_disable(event);
 	}
 }
-
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index d28687e7b3a7..10f6ad7d85f6 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -78,13 +78,14 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth)
 	current->ret_stack[index].ret = ret;
 	current->ret_stack[index].func = func;
 	current->ret_stack[index].calltime = calltime;
+	current->ret_stack[index].subtime = 0;
 	*depth = index;
 
 	return 0;
 }
 
 /* Retrieve a function return address to the trace stack on thread info.*/
-void
+static void
 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 {
 	int index;
@@ -104,9 +105,6 @@ ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret)
 	trace->calltime = current->ret_stack[index].calltime;
 	trace->overrun = atomic_read(&current->trace_overrun);
 	trace->depth = index;
-	barrier();
-	current->curr_ret_stack--;
-
 }
 
 /*
@@ -121,6 +119,8 @@ unsigned long ftrace_return_to_handler(void)
 	ftrace_pop_return_trace(&trace, &ret);
 	trace.rettime = trace_clock_local();
 	ftrace_graph_return(&trace);
+	barrier();
+	current->curr_ret_stack--;
 
 	if (unlikely(!ret)) {
 		ftrace_graph_stop();
@@ -426,8 +426,8 @@ print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 	return TRACE_TYPE_HANDLED;
 }
 
-static enum print_line_t
-print_graph_duration(unsigned long long duration, struct trace_seq *s)
+enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
 	unsigned long nsecs_rem = do_div(duration, 1000);
 	/* log10(ULONG_MAX) + '\0' */
@@ -464,12 +464,23 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s)
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
+	return TRACE_TYPE_HANDLED;
+}
+
+static enum print_line_t
+print_graph_duration(unsigned long long duration, struct trace_seq *s)
+{
+	int ret;
+
+	ret = trace_print_graph_duration(duration, s);
+	if (ret != TRACE_TYPE_HANDLED)
+		return ret;
 
 	ret = trace_seq_printf(s, "|  ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
-	return TRACE_TYPE_HANDLED;
 
+	return TRACE_TYPE_HANDLED;
 }
 
 /* Case of a leaf function on its call entry */
diff --git a/kernel/trace/trace_mmiotrace.c b/kernel/trace/trace_mmiotrace.c
index 8e37fcddd8b4..d53b45ed0806 100644
--- a/kernel/trace/trace_mmiotrace.c
+++ b/kernel/trace/trace_mmiotrace.c
@@ -9,6 +9,8 @@
 #include <linux/kernel.h>
 #include <linux/mmiotrace.h>
 #include <linux/pci.h>
+#include <linux/time.h>
+
 #include <asm/atomic.h>
 
 #include "trace.h"
@@ -174,7 +176,7 @@ static enum print_line_t mmio_print_rw(struct trace_iterator *iter)
 	struct mmiotrace_rw *rw;
 	struct trace_seq *s	= &iter->seq;
 	unsigned long long t	= ns2usecs(iter->ts);
-	unsigned long usec_rem	= do_div(t, 1000000ULL);
+	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
 	int ret = 1;
 
@@ -221,7 +223,7 @@ static enum print_line_t mmio_print_map(struct trace_iterator *iter)
 	struct mmiotrace_map *m;
 	struct trace_seq *s	= &iter->seq;
 	unsigned long long t	= ns2usecs(iter->ts);
-	unsigned long usec_rem	= do_div(t, 1000000ULL);
+	unsigned long usec_rem	= do_div(t, USEC_PER_SEC);
 	unsigned secs		= (unsigned long)t;
 	int ret;
 
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 64b54a59c55b..0e70fb07ca78 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -19,6 +19,16 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly;
 
 static int next_event_type = __TRACE_LAST_TYPE + 1;
 
+void trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
+
+	s->buffer[len] = 0;
+	seq_puts(m, s->buffer);
+
+	trace_seq_init(s);
+}
+
 enum print_line_t trace_print_bprintk_msg_only(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h
index e0bde39c2dd9..91630217fb46 100644
--- a/kernel/trace/trace_output.h
+++ b/kernel/trace/trace_output.h
@@ -20,6 +20,8 @@ trace_print_bprintk_msg_only(struct trace_iterator *iter);
 extern enum print_line_t
 trace_print_printk_msg_only(struct trace_iterator *iter);
 
+extern void trace_print_seq(struct seq_file *m, struct trace_seq *s);
+
 extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
 extern int
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index eb81556107fe..9bece9687b62 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -245,17 +245,13 @@ static const struct file_operations ftrace_formats_fops = {
 static __init int init_trace_printk_function_export(void)
 {
 	struct dentry *d_tracer;
-	struct dentry *entry;
 
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
 		return 0;
 
-	entry = debugfs_create_file("printk_formats", 0444, d_tracer,
+	trace_create_file("printk_formats", 0444, d_tracer,
 				    NULL, &ftrace_formats_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs "
-			   "'printk_formats' entry\n");
 
 	return 0;
 }
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 9117cea6f1ae..9d8cccdfaa06 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -29,13 +29,13 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 	int cpu;
 	int pc;
 
-	if (!sched_ref || sched_stopped)
+	if (unlikely(!sched_ref))
 		return;
 
 	tracing_record_cmdline(prev);
 	tracing_record_cmdline(next);
 
-	if (!tracer_enabled)
+	if (!tracer_enabled || sched_stopped)
 		return;
 
 	pc = preempt_count();
@@ -56,15 +56,15 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 	unsigned long flags;
 	int cpu, pc;
 
-	if (!likely(tracer_enabled))
+	if (unlikely(!sched_ref))
 		return;
 
-	pc = preempt_count();
 	tracing_record_cmdline(current);
 
-	if (sched_stopped)
+	if (!tracer_enabled || sched_stopped)
 		return;
 
+	pc = preempt_count();
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = ctx_trace->data[cpu];
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index c750f65f9661..1796f00524e1 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -352,19 +352,14 @@ __setup("stacktrace", enable_stacktrace);
 static __init int stack_trace_init(void)
 {
 	struct dentry *d_tracer;
-	struct dentry *entry;
 
 	d_tracer = tracing_init_dentry();
 
-	entry = debugfs_create_file("stack_max_size", 0644, d_tracer,
-				    &max_stack_size, &stack_max_size_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'stack_max_size' entry\n");
+	trace_create_file("stack_max_size", 0644, d_tracer,
+			&max_stack_size, &stack_max_size_fops);
 
-	entry = debugfs_create_file("stack_trace", 0444, d_tracer,
-				    NULL, &stack_trace_fops);
-	if (!entry)
-		pr_warning("Could not create debugfs 'stack_trace' entry\n");
+	trace_create_file("stack_trace", 0444, d_tracer,
+			NULL, &stack_trace_fops);
 
 	if (stack_tracer_enabled)
 		register_ftrace_function(&trace_ops);
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index acdebd771a93..fdde3a4a94cd 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -85,7 +85,7 @@ static int stat_seq_init(struct tracer_stat_session *session)
 	if (!ts->stat_cmp)
 		ts->stat_cmp = dummy_cmp;
 
-	stat = ts->stat_start();
+	stat = ts->stat_start(ts);
 	if (!stat)
 		goto exit;
 
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
index 202274cf7f3d..f3546a2cd826 100644
--- a/kernel/trace/trace_stat.h
+++ b/kernel/trace/trace_stat.h
@@ -12,7 +12,7 @@ struct tracer_stat {
 	/* The name of your stat file */
 	const char		*name;
 	/* Iteration over statistic entries */
-	void			*(*stat_start)(void);
+	void			*(*stat_start)(struct tracer_stat *trace);
 	void			*(*stat_next)(void *prev, int idx);
 	/* Compare two entries for stats sorting */
 	int			(*stat_cmp)(void *p1, void *p2);
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index 91fd19c2149f..e04b76cc238a 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -321,11 +321,7 @@ static const struct file_operations sysprof_sample_fops = {
 
 void init_tracer_sysprof_debugfs(struct dentry *d_tracer)
 {
-	struct dentry *entry;
 
-	entry = debugfs_create_file("sysprof_sample_period", 0644,
+	trace_create_file("sysprof_sample_period", 0644,
 			d_tracer, NULL, &sysprof_sample_fops);
-	if (entry)
-		return;
-	pr_warning("Could not create debugfs 'sysprof_sample_period' entry\n");
 }
diff --git a/kernel/trace/trace_workqueue.c b/kernel/trace/trace_workqueue.c
index 797201e4a137..984b9175c13d 100644
--- a/kernel/trace/trace_workqueue.c
+++ b/kernel/trace/trace_workqueue.c
@@ -152,7 +152,7 @@ static struct cpu_workqueue_stats *workqueue_stat_start_cpu(int cpu)
 	return ret;
 }
 
-static void *workqueue_stat_start(void)
+static void *workqueue_stat_start(struct tracer_stat *trace)
 {
 	int cpu;
 	void *ret = NULL;