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Commit 915a0b575fdb2376135ed9334b3ccb1eb51db622

Authored by Ingo Molnar 2010-03-11 20:39:33 +0800

Exists in master and in 7 other branches

Merge branch 'tip/tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git…

…/rostedt/linux-2.6-trace into tracing/urgent

Showing 4 changed files Inline Diff

kernel/trace/ftrace.c
kernel/trace/trace.c
kernel/trace/trace.h
kernel/trace/trace_functions_graph.c

kernel/trace/ftrace.c

Diff comments View file @ 915a0b5

 /*
  * Infrastructure for profiling code inserted by 'gcc -pg'.
  *
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
  *
  * Originally ported from the -rt patch by:
  *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  *
  * Based on code in the latency_tracer, that is:
  *
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 William Lee Irwin III
  */
 #include <linux/stop_machine.h>
 #include <linux/clocksource.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
 #include <linux/suspend.h>
 #include <linux/debugfs.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/sysctl.h>
 #include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/hash.h>
 #include <trace/events/sched.h>
 #include <asm/ftrace.h>
 #include <asm/setup.h>
 #include "trace_output.h"
 #include "trace_stat.h"
 #define FTRACE_WARN_ON(cond)			\
 	do {					\
 		if (WARN_ON(cond))		\
 			ftrace_kill();		\
 	} while (0)
 #define FTRACE_WARN_ON_ONCE(cond)		\
 	do {					\
 		if (WARN_ON_ONCE(cond))		\
 			ftrace_kill();		\
 	} while (0)
 /* hash bits for specific function selection */
 #define FTRACE_HASH_BITS 7
 #define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
 /* ftrace_enabled is a method to turn ftrace on or off */
 int ftrace_enabled __read_mostly;
 static int last_ftrace_enabled;
 /* Quick disabling of function tracer. */
 int function_trace_stop;
 /* List for set_ftrace_pid's pids. */
 LIST_HEAD(ftrace_pids);
 struct ftrace_pid {
 	struct list_head list;
 	struct pid *pid;
 };
 /*
  * ftrace_disabled is set when an anomaly is discovered.
  * ftrace_disabled is much stronger than ftrace_enabled.
  */
 static int ftrace_disabled __read_mostly;
 static DEFINE_MUTEX(ftrace_lock);
 static struct ftrace_ops ftrace_list_end __read_mostly =
 {
 	.func		= ftrace_stub,
 };
 static struct ftrace_ops *ftrace_list __read_mostly = &ftrace_list_end;
 ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
-#endif
 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
 {
 	struct ftrace_ops *op = ftrace_list;
 	/* in case someone actually ports this to alpha! */
 	read_barrier_depends();
 	while (op != &ftrace_list_end) {
 		/* silly alpha */
 		read_barrier_depends();
 		op->func(ip, parent_ip);
 		op = op->next;
 	};
 }
 static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 {
 	if (!test_tsk_trace_trace(current))
 		return;
 	ftrace_pid_function(ip, parent_ip);
 }
 static void set_ftrace_pid_function(ftrace_func_t func)
 {
 	/* do not set ftrace_pid_function to itself! */
 	if (func != ftrace_pid_func)
 		ftrace_pid_function = func;
 }
 /**
  * clear_ftrace_function - reset the ftrace function
  *
  * This NULLs the ftrace function and in essence stops
  * tracing.  There may be lag
  */
 void clear_ftrace_function(void)
 {
 	ftrace_trace_function = ftrace_stub;
 	__ftrace_trace_function = ftrace_stub;
 	ftrace_pid_function = ftrace_stub;
 }
 #ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 /*
  * For those archs that do not test ftrace_trace_stop in their
  * mcount call site, we need to do it from C.
  */
 static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 {
 	if (function_trace_stop)
 		return;
 	__ftrace_trace_function(ip, parent_ip);
 }
 #endif
 static int __register_ftrace_function(struct ftrace_ops *ops)
 {
 	ops->next = ftrace_list;
 	/*
 	 * We are entering ops into the ftrace_list but another
 	 * CPU might be walking that list. We need to make sure
 	 * the ops->next pointer is valid before another CPU sees
 	 * the ops pointer included into the ftrace_list.
 	 */
 	smp_wmb();
 	ftrace_list = ops;
 	if (ftrace_enabled) {
 		ftrace_func_t func;
 		if (ops->next == &ftrace_list_end)
 			func = ops->func;
 		else
 			func = ftrace_list_func;
 		if (!list_empty(&ftrace_pids)) {
 			set_ftrace_pid_function(func);
 			func = ftrace_pid_func;
 		}
 		/*
 		 * For one func, simply call it directly.
 		 * For more than one func, call the chain.
 		 */
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 		ftrace_trace_function = func;
 #else
 		__ftrace_trace_function = func;
 		ftrace_trace_function = ftrace_test_stop_func;
 #endif
 	}
 	return 0;
 }
 static int __unregister_ftrace_function(struct ftrace_ops *ops)
 {
 	struct ftrace_ops **p;
 	/*
 	 * If we are removing the last function, then simply point
 	 * to the ftrace_stub.
 	 */
 	if (ftrace_list == ops && ops->next == &ftrace_list_end) {
 		ftrace_trace_function = ftrace_stub;
 		ftrace_list = &ftrace_list_end;
 		return 0;
 	}
 	for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
 		if (*p == ops)
 			break;
 	if (*p != ops)
 		return -1;
 	*p = (*p)->next;
 	if (ftrace_enabled) {
 		/* If we only have one func left, then call that directly */
 		if (ftrace_list->next == &ftrace_list_end) {
 			ftrace_func_t func = ftrace_list->func;
 			if (!list_empty(&ftrace_pids)) {
 				set_ftrace_pid_function(func);
 				func = ftrace_pid_func;
 			}
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 			ftrace_trace_function = func;
 #else
 			__ftrace_trace_function = func;
 #endif
 		}
 	}
 	return 0;
 }
 static void ftrace_update_pid_func(void)
 {
 	ftrace_func_t func;
 	if (ftrace_trace_function == ftrace_stub)
 		return;
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	func = ftrace_trace_function;
 #else
 	func = __ftrace_trace_function;
 #endif
 	if (!list_empty(&ftrace_pids)) {
 		set_ftrace_pid_function(func);
 		func = ftrace_pid_func;
 	} else {
 		if (func == ftrace_pid_func)
 			func = ftrace_pid_function;
 	}
 #ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	ftrace_trace_function = func;
 #else
 	__ftrace_trace_function = func;
 #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:
 	if (idx != 0)
 		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 || !ftrace_profile_enabled)
 		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 || !ftrace_profile_enabled)
 		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 calls stop_machine
 			 * so this acts like an synchronize_sched.
 			 */
 			unregister_ftrace_profiler();
 		}
 	}
  out:
 	mutex_unlock(&ftrace_profile_lock);
 	*ppos += 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 __init 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.
 			 */
 			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 __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 {
 }
 #endif /* CONFIG_FUNCTION_PROFILER */
 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 #ifdef CONFIG_DYNAMIC_FTRACE
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
 # error Dynamic ftrace depends on MCOUNT_RECORD
 #endif
 static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 struct ftrace_func_probe {
 	struct hlist_node	node;
 	struct ftrace_probe_ops	*ops;
 	unsigned long		flags;
 	unsigned long		ip;
 	void			*data;
 	struct rcu_head		rcu;
 };
 enum {
 	FTRACE_ENABLE_CALLS		= (1 << 0),
 	FTRACE_DISABLE_CALLS		= (1 << 1),
 	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
 	FTRACE_ENABLE_MCOUNT		= (1 << 3),
 	FTRACE_DISABLE_MCOUNT		= (1 << 4),
 	FTRACE_START_FUNC_RET		= (1 << 5),
 	FTRACE_STOP_FUNC_RET		= (1 << 6),
 };
 static int ftrace_filtered;
 static struct dyn_ftrace *ftrace_new_addrs;
 static DEFINE_MUTEX(ftrace_regex_lock);
 struct ftrace_page {
 	struct ftrace_page	*next;
 	int			index;
 	struct dyn_ftrace	records[];
 };
 #define ENTRIES_PER_PAGE \
   ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 /* estimate from running different kernels */
 #define NR_TO_INIT		10000
 static struct ftrace_page	*ftrace_pages_start;
 static struct ftrace_page	*ftrace_pages;
 static struct dyn_ftrace *ftrace_free_records;
 /*
  * This is a double for. Do not use 'break' to break out of the loop,
  * you must use a goto.
  */
 #define do_for_each_ftrace_rec(pg, rec)					\
 	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
 		int _____i;						\
 		for (_____i = 0; _____i < pg->index; _____i++) {	\
 			rec = &pg->records[_____i];
 #define while_for_each_ftrace_rec()		\
 		}				\
 	}
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
 	rec->freelist = ftrace_free_records;
 	ftrace_free_records = rec;
 	rec->flags |= FTRACE_FL_FREE;
 }
 static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 {
 	struct dyn_ftrace *rec;
 	/* First check for freed records */
 	if (ftrace_free_records) {
 		rec = ftrace_free_records;
 		if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
 			FTRACE_WARN_ON_ONCE(1);
 			ftrace_free_records = NULL;
 			return NULL;
 		}
 		ftrace_free_records = rec->freelist;
 		memset(rec, 0, sizeof(*rec));
 		return rec;
 	}
 	if (ftrace_pages->index == ENTRIES_PER_PAGE) {
 		if (!ftrace_pages->next) {
 			/* allocate another page */
 			ftrace_pages->next =
 				(void *)get_zeroed_page(GFP_KERNEL);
 			if (!ftrace_pages->next)
 				return NULL;
 		}
 		ftrace_pages = ftrace_pages->next;
 	}
 	return &ftrace_pages->records[ftrace_pages->index++];
 }
 static struct dyn_ftrace *
 ftrace_record_ip(unsigned long ip)
 {
 	struct dyn_ftrace *rec;
 	if (ftrace_disabled)
 		return NULL;
 	rec = ftrace_alloc_dyn_node(ip);
 	if (!rec)
 		return NULL;
 	rec->ip = ip;
 	rec->newlist = ftrace_new_addrs;
 	ftrace_new_addrs = rec;
 	return rec;
 }
 static void print_ip_ins(const char *fmt, unsigned char *p)
 {
 	int i;
 	printk(KERN_CONT "%s", fmt);
 	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
 		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
 }
 static void ftrace_bug(int failed, unsigned long ip)
 {
 	switch (failed) {
 	case -EFAULT:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on modifying ");
 		print_ip_sym(ip);
 		break;
 	case -EINVAL:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace failed to modify ");
 		print_ip_sym(ip);
 		print_ip_ins(" actual: ", (unsigned char *)ip);
 		printk(KERN_CONT "\n");
 		break;
 	case -EPERM:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on writing ");
 		print_ip_sym(ip);
 		break;
 	default:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on unknown error ");
 		print_ip_sym(ip);
 	}
 }
 /* Return 1 if the address range is reserved for ftrace */
 int ftrace_text_reserved(void *start, void *end)
 {
 	struct dyn_ftrace *rec;
 	struct ftrace_page *pg;
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->ip <= (unsigned long)end &&
 		    rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
 			return 1;
 	} while_for_each_ftrace_rec();
 	return 0;
 }
 static int
 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 {
 	unsigned long ftrace_addr;
 	unsigned long flag = 0UL;
 	ftrace_addr = (unsigned long)FTRACE_ADDR;
 	/*
 	 * If this record is not to be traced or we want to disable it,
 	 * then disable it.
 	 *
 	 * If we want to enable it and filtering is off, then enable it.
 	 *
 	 * If we want to enable it and filtering is on, enable it only if
 	 * it's filtered
 	 */
 	if (enable && !(rec->flags & FTRACE_FL_NOTRACE)) {
 		if (!ftrace_filtered || (rec->flags & FTRACE_FL_FILTER))
 			flag = FTRACE_FL_ENABLED;
 	}
 	/* If the state of this record hasn't changed, then do nothing */
 	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
 		return 0;
 	if (flag) {
 		rec->flags |= FTRACE_FL_ENABLED;
 		return ftrace_make_call(rec, ftrace_addr);
 	}
 	rec->flags &= ~FTRACE_FL_ENABLED;
 	return ftrace_make_nop(NULL, rec, ftrace_addr);
 }
 static void ftrace_replace_code(int enable)
 {
 	struct dyn_ftrace *rec;
 	struct ftrace_page *pg;
 	int failed;
 	do_for_each_ftrace_rec(pg, rec) {
 		/*
 		 * Skip over free records, records that have
 		 * failed and not converted.
 		 */
 		if (rec->flags & FTRACE_FL_FREE ||
 		    rec->flags & FTRACE_FL_FAILED ||
 		    !(rec->flags & FTRACE_FL_CONVERTED))
 			continue;
 		failed = __ftrace_replace_code(rec, enable);
 		if (failed) {
 			rec->flags |= FTRACE_FL_FAILED;
 			ftrace_bug(failed, rec->ip);
 			/* Stop processing */
 			return;
 		}
 	} while_for_each_ftrace_rec();
 }
 static int
 ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
 {
 	unsigned long ip;
 	int ret;
 	ip = rec->ip;
 	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
 	if (ret) {
 		ftrace_bug(ret, ip);
 		rec->flags |= FTRACE_FL_FAILED;
 		return 0;
 	}
 	return 1;
 }
 /*
  * archs can override this function if they must do something
  * before the modifying code is performed.
  */
 int __weak ftrace_arch_code_modify_prepare(void)
 {
 	return 0;
 }
 /*
  * archs can override this function if they must do something
  * after the modifying code is performed.
  */
 int __weak ftrace_arch_code_modify_post_process(void)
 {
 	return 0;
 }
 static int __ftrace_modify_code(void *data)
 {
 	int *command = data;
 	if (*command & FTRACE_ENABLE_CALLS)
 		ftrace_replace_code(1);
 	else if (*command & FTRACE_DISABLE_CALLS)
 		ftrace_replace_code(0);
 	if (*command & FTRACE_UPDATE_TRACE_FUNC)
 		ftrace_update_ftrace_func(ftrace_trace_function);
 	if (*command & FTRACE_START_FUNC_RET)
 		ftrace_enable_ftrace_graph_caller();
 	else if (*command & FTRACE_STOP_FUNC_RET)
 		ftrace_disable_ftrace_graph_caller();
 	return 0;
 }
 static void ftrace_run_update_code(int command)
 {
 	int ret;
 	ret = ftrace_arch_code_modify_prepare();
 	FTRACE_WARN_ON(ret);
 	if (ret)
 		return;
 	stop_machine(__ftrace_modify_code, &command, NULL);
 	ret = ftrace_arch_code_modify_post_process();
 	FTRACE_WARN_ON(ret);
 }
 static ftrace_func_t saved_ftrace_func;
 static int ftrace_start_up;
 static void ftrace_startup_enable(int command)
 {
 	if (saved_ftrace_func != ftrace_trace_function) {
 		saved_ftrace_func = ftrace_trace_function;
 		command |= FTRACE_UPDATE_TRACE_FUNC;
 	}
 	if (!command || !ftrace_enabled)
 		return;
 	ftrace_run_update_code(command);
 }
 static void ftrace_startup(int command)
 {
 	if (unlikely(ftrace_disabled))
 		return;
 	ftrace_start_up++;
 	command |= FTRACE_ENABLE_CALLS;
 	ftrace_startup_enable(command);
 }
 static void ftrace_shutdown(int command)
 {
 	if (unlikely(ftrace_disabled))
 		return;
 	ftrace_start_up--;
 	/*
 	 * Just warn in case of unbalance, no need to kill ftrace, it's not
 	 * critical but the ftrace_call callers may be never nopped again after
 	 * further ftrace uses.
 	 */
 	WARN_ON_ONCE(ftrace_start_up < 0);
 	if (!ftrace_start_up)
 		command |= FTRACE_DISABLE_CALLS;
 	if (saved_ftrace_func != ftrace_trace_function) {
 		saved_ftrace_func = ftrace_trace_function;
 		command |= FTRACE_UPDATE_TRACE_FUNC;
 	}
 	if (!command || !ftrace_enabled)
 		return;
 	ftrace_run_update_code(command);
 }
 static void ftrace_startup_sysctl(void)
 {
 	int command = FTRACE_ENABLE_MCOUNT;
 	if (unlikely(ftrace_disabled))
 		return;
 	/* Force update next time */
 	saved_ftrace_func = NULL;
 	/* ftrace_start_up is true if we want ftrace running */
 	if (ftrace_start_up)
 		command |= FTRACE_ENABLE_CALLS;
 	ftrace_run_update_code(command);
 }
 static void ftrace_shutdown_sysctl(void)
 {
 	int command = FTRACE_DISABLE_MCOUNT;
 	if (unlikely(ftrace_disabled))
 		return;
 	/* ftrace_start_up is true if ftrace is running */
 	if (ftrace_start_up)
 		command |= FTRACE_DISABLE_CALLS;
 	ftrace_run_update_code(command);
 }
 static cycle_t		ftrace_update_time;
 static unsigned long	ftrace_update_cnt;
 unsigned long		ftrace_update_tot_cnt;
 static int ftrace_update_code(struct module *mod)
 {
 	struct dyn_ftrace *p;
 	cycle_t start, stop;
 	start = ftrace_now(raw_smp_processor_id());
 	ftrace_update_cnt = 0;
 	while (ftrace_new_addrs) {
 		/* If something went wrong, bail without enabling anything */
 		if (unlikely(ftrace_disabled))
 			return -1;
 		p = ftrace_new_addrs;
 		ftrace_new_addrs = p->newlist;
 		p->flags = 0L;
 		/*
 		 * Do the initial record convertion from mcount jump
 		 * to the NOP instructions.
 		 */
 		if (!ftrace_code_disable(mod, p)) {
 			ftrace_free_rec(p);
 			continue;
 		}
 		p->flags |= FTRACE_FL_CONVERTED;
 		ftrace_update_cnt++;
 		/*
 		 * If the tracing is enabled, go ahead and enable the record.
 		 *
 		 * The reason not to enable the record immediatelly is the
 		 * inherent check of ftrace_make_nop/ftrace_make_call for
 		 * correct previous instructions.  Making first the NOP
 		 * conversion puts the module to the correct state, thus
 		 * passing the ftrace_make_call check.
 		 */
 		if (ftrace_start_up) {
 			int failed = __ftrace_replace_code(p, 1);
 			if (failed) {
 				ftrace_bug(failed, p->ip);
 				ftrace_free_rec(p);
 			}
 		}
 	}
 	stop = ftrace_now(raw_smp_processor_id());
 	ftrace_update_time = stop - start;
 	ftrace_update_tot_cnt += ftrace_update_cnt;
 	return 0;
 }
 static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
 {
 	struct ftrace_page *pg;
 	int cnt;
 	int i;
 	/* allocate a few pages */
 	ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
 	if (!ftrace_pages_start)
 		return -1;
 	/*
 	 * Allocate a few more pages.
 	 *
 	 * TODO: have some parser search vmlinux before
 	 *   final linking to find all calls to ftrace.
 	 *   Then we can:
 	 *    a) know how many pages to allocate.
 	 *     and/or
 	 *    b) set up the table then.
 	 *
 	 *  The dynamic code is still necessary for
 	 *  modules.
 	 */
 	pg = ftrace_pages = ftrace_pages_start;
 	cnt = num_to_init / ENTRIES_PER_PAGE;
 	pr_info("ftrace: allocating %ld entries in %d pages\n",
 		num_to_init, cnt + 1);
 	for (i = 0; i < cnt; i++) {
 		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 		/* If we fail, we'll try later anyway */
 		if (!pg->next)
 			break;
 		pg = pg->next;
 	}
 	return 0;
 }
 enum {
 	FTRACE_ITER_FILTER	= (1 << 0),
 	FTRACE_ITER_NOTRACE	= (1 << 1),
 	FTRACE_ITER_FAILURES	= (1 << 2),
 	FTRACE_ITER_PRINTALL	= (1 << 3),
 	FTRACE_ITER_HASH	= (1 << 4),
 };
 #define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
 struct ftrace_iterator {
 	struct ftrace_page	*pg;
 	int			hidx;
 	int			idx;
 	unsigned		flags;
 	struct trace_parser	parser;
 };
 static void *
 t_hash_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	struct hlist_node *hnd = v;
 	struct hlist_head *hhd;
 	WARN_ON(!(iter->flags & FTRACE_ITER_HASH));
 	(*pos)++;
  retry:
 	if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
 		return NULL;
 	hhd = &ftrace_func_hash[iter->hidx];
 	if (hlist_empty(hhd)) {
 		iter->hidx++;
 		hnd = NULL;
 		goto retry;
 	}
 	if (!hnd)
 		hnd = hhd->first;
 	else {
 		hnd = hnd->next;
 		if (!hnd) {
 			iter->hidx++;
 			goto retry;
 		}
 	}
 	return hnd;
 }
 static void *t_hash_start(struct seq_file *m, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	void *p = NULL;
 	loff_t l;
 	if (!(iter->flags & FTRACE_ITER_HASH))
 		*pos = 0;
 	iter->flags |= FTRACE_ITER_HASH;
 	iter->hidx = 0;
 	for (l = 0; l <= *pos; ) {
 		p = t_hash_next(m, p, &l);
 		if (!p)
 			break;
 	}
 	return p;
 }
 static int t_hash_show(struct seq_file *m, void *v)
 {
 	struct ftrace_func_probe *rec;
 	struct hlist_node *hnd = v;
 	rec = hlist_entry(hnd, struct ftrace_func_probe, node);
 	if (rec->ops->print)
 		return rec->ops->print(m, rec->ip, rec->ops, rec->data);
 	seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
 	if (rec->data)
 		seq_printf(m, ":%p", rec->data);
 	seq_putc(m, '\n');
 	return 0;
 }
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	struct dyn_ftrace *rec = NULL;
 	if (iter->flags & FTRACE_ITER_HASH)
 		return t_hash_next(m, v, pos);
 	(*pos)++;
 	if (iter->flags & FTRACE_ITER_PRINTALL)
 		return NULL;
  retry:
 	if (iter->idx >= iter->pg->index) {
 		if (iter->pg->next) {
 			iter->pg = iter->pg->next;
 			iter->idx = 0;
 			goto retry;
 		}
 	} else {
 		rec = &iter->pg->records[iter->idx++];
 		if ((rec->flags & FTRACE_FL_FREE) ||
 		    (!(iter->flags & FTRACE_ITER_FAILURES) &&
 		     (rec->flags & FTRACE_FL_FAILED)) ||
 		    ((iter->flags & FTRACE_ITER_FAILURES) &&
 		     !(rec->flags & FTRACE_FL_FAILED)) ||
 		    ((iter->flags & FTRACE_ITER_FILTER) &&
 		     !(rec->flags & FTRACE_FL_FILTER)) ||
 		    ((iter->flags & FTRACE_ITER_NOTRACE) &&
 		     !(rec->flags & FTRACE_FL_NOTRACE))) {
 			rec = NULL;
 			goto retry;
 		}
 	}
 	return rec;
 }
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
 	struct ftrace_iterator *iter = m->private;
 	void *p = NULL;
 	loff_t l;
 	mutex_lock(&ftrace_lock);
 	/*
 	 * For set_ftrace_filter reading, if we have the filter
 	 * off, we can short cut and just print out that all
 	 * functions are enabled.
 	 */
 	if (iter->flags & FTRACE_ITER_FILTER && !ftrace_filtered) {
 		if (*pos > 0)
 			return t_hash_start(m, pos);
 		iter->flags |= FTRACE_ITER_PRINTALL;
 		return iter;
 	}
 	if (iter->flags & FTRACE_ITER_HASH)
 		return t_hash_start(m, pos);
 	iter->pg = ftrace_pages_start;
 	iter->idx = 0;
 	for (l = 0; l <= *pos; ) {
 		p = t_next(m, p, &l);
 		if (!p)
 			break;
 	}
 	if (!p && iter->flags & FTRACE_ITER_FILTER)
 		return t_hash_start(m, pos);
 	return p;
 }
 static void t_stop(struct seq_file *m, void *p)
 {
 	mutex_unlock(&ftrace_lock);
 }
 static int t_show(struct seq_file *m, void *v)
 {
 	struct ftrace_iterator *iter = m->private;
 	struct dyn_ftrace *rec = v;
 	if (iter->flags & FTRACE_ITER_HASH)
 		return t_hash_show(m, v);
 	if (iter->flags & FTRACE_ITER_PRINTALL) {
 		seq_printf(m, "#### all functions enabled ####\n");
 		return 0;
 	}
 	if (!rec)
 		return 0;
 	seq_printf(m, "%ps\n", (void *)rec->ip);
 	return 0;
 }
 static const struct seq_operations show_ftrace_seq_ops = {
 	.start = t_start,
 	.next = t_next,
 	.stop = t_stop,
 	.show = t_show,
 };
 static int
 ftrace_avail_open(struct inode *inode, struct file *file)
 {
 	struct ftrace_iterator *iter;
 	int ret;
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (!iter)
 		return -ENOMEM;
 	iter->pg = ftrace_pages_start;
 	ret = seq_open(file, &show_ftrace_seq_ops);
 	if (!ret) {
 		struct seq_file *m = file->private_data;
 		m->private = iter;
 	} else {
 		kfree(iter);
 	}
 	return ret;
 }
 static int
 ftrace_failures_open(struct inode *inode, struct file *file)
 {
 	int ret;
 	struct seq_file *m;
 	struct ftrace_iterator *iter;
 	ret = ftrace_avail_open(inode, file);
 	if (!ret) {
 		m = (struct seq_file *)file->private_data;
 		iter = (struct ftrace_iterator *)m->private;
 		iter->flags = FTRACE_ITER_FAILURES;
 	}
 	return ret;
 }
 static void ftrace_filter_reset(int enable)
 {
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
 	unsigned long type = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	mutex_lock(&ftrace_lock);
 	if (enable)
 		ftrace_filtered = 0;
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->flags & FTRACE_FL_FAILED)
 			continue;
 		rec->flags &= ~type;
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
 }
 static int
 ftrace_regex_open(struct inode *inode, struct file *file, int enable)
 {
 	struct ftrace_iterator *iter;
 	int ret = 0;
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (!iter)
 		return -ENOMEM;
 	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
 		kfree(iter);
 		return -ENOMEM;
 	}
 	mutex_lock(&ftrace_regex_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
 		ftrace_filter_reset(enable);
 	if (file->f_mode & FMODE_READ) {
 		iter->pg = ftrace_pages_start;
 		iter->flags = enable ? FTRACE_ITER_FILTER :
 			FTRACE_ITER_NOTRACE;
 		ret = seq_open(file, &show_ftrace_seq_ops);
 		if (!ret) {
 			struct seq_file *m = file->private_data;
 			m->private = iter;
 		} else {
 			trace_parser_put(&iter->parser);
 			kfree(iter);
 		}
 	} else
 		file->private_data = iter;
 	mutex_unlock(&ftrace_regex_lock);
 	return ret;
 }
 static int
 ftrace_filter_open(struct inode *inode, struct file *file)
 {
 	return ftrace_regex_open(inode, file, 1);
 }
 static int
 ftrace_notrace_open(struct inode *inode, struct file *file)
 {
 	return ftrace_regex_open(inode, file, 0);
 }
 static loff_t
 ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
 {
 	loff_t ret;
 	if (file->f_mode & FMODE_READ)
 		ret = seq_lseek(file, offset, origin);
 	else
 		file->f_pos = ret = 1;
 	return ret;
 }
 static int ftrace_match(char *str, char *regex, int len, int type)
 {
 	int matched = 0;
 	int slen;
 	switch (type) {
 	case MATCH_FULL:
 		if (strcmp(str, regex) == 0)
 			matched = 1;
 		break;
 	case MATCH_FRONT_ONLY:
 		if (strncmp(str, regex, len) == 0)
 			matched = 1;
 		break;
 	case MATCH_MIDDLE_ONLY:
 		if (strstr(str, regex))
 			matched = 1;
 		break;
 	case MATCH_END_ONLY:
 		slen = strlen(str);
 		if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
 			matched = 1;
 		break;
 	}
 	return matched;
 }
 static int
 ftrace_match_record(struct dyn_ftrace *rec, char *regex, int len, int type)
 {
 	char str[KSYM_SYMBOL_LEN];
 	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 	return ftrace_match(str, regex, len, type);
 }
 static int ftrace_match_records(char *buff, int len, int enable)
 {
 	unsigned int search_len;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
 	unsigned long flag;
 	char *search;
 	int type;
 	int not;
 	int found = 0;
 	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	type = filter_parse_regex(buff, len, &search, &not);
 	search_len = strlen(search);
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->flags & FTRACE_FL_FAILED)
 			continue;
 		if (ftrace_match_record(rec, search, search_len, type)) {
 			if (not)
 				rec->flags &= ~flag;
 			else
 				rec->flags |= flag;
 			found = 1;
 		}
 		/*
 		 * Only enable filtering if we have a function that
 		 * is filtered on.
 		 */
 		if (enable && (rec->flags & FTRACE_FL_FILTER))
 			ftrace_filtered = 1;
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
 	return found;
 }
 static int
 ftrace_match_module_record(struct dyn_ftrace *rec, char *mod,
 			   char *regex, int len, int type)
 {
 	char str[KSYM_SYMBOL_LEN];
 	char *modname;
 	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
 	if (!modname || strcmp(modname, mod))
 		return 0;
 	/* blank search means to match all funcs in the mod */
 	if (len)
 		return ftrace_match(str, regex, len, type);
 	else
 		return 1;
 }
 static int ftrace_match_module_records(char *buff, char *mod, int enable)
 {
 	unsigned search_len = 0;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
 	int type = MATCH_FULL;
 	char *search = buff;
 	unsigned long flag;
 	int not = 0;
 	int found = 0;
 	flag = enable ? FTRACE_FL_FILTER : FTRACE_FL_NOTRACE;
 	/* blank or '*' mean the same */
 	if (strcmp(buff, "*") == 0)
 		buff[0] = 0;
 	/* handle the case of 'dont filter this module' */
 	if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
 		buff[0] = 0;
 		not = 1;
 	}
 	if (strlen(buff)) {
 		type = filter_parse_regex(buff, strlen(buff), &search, &not);
 		search_len = strlen(search);
 	}
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->flags & FTRACE_FL_FAILED)
 			continue;
 		if (ftrace_match_module_record(rec, mod,
 					       search, search_len, type)) {
 			if (not)
 				rec->flags &= ~flag;
 			else
 				rec->flags |= flag;
 			found = 1;
 		}
 		if (enable && (rec->flags & FTRACE_FL_FILTER))
 			ftrace_filtered = 1;
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
 	return found;
 }
 /*
  * We register the module command as a template to show others how
  * to register the a command as well.
  */
 static int
 ftrace_mod_callback(char *func, char *cmd, char *param, int enable)
 {
 	char *mod;
 	/*
 	 * cmd == 'mod' because we only registered this func
 	 * for the 'mod' ftrace_func_command.
 	 * But if you register one func with multiple commands,
 	 * you can tell which command was used by the cmd
 	 * parameter.
 	 */
 	/* we must have a module name */
 	if (!param)
 		return -EINVAL;
 	mod = strsep(&param, ":");
 	if (!strlen(mod))
 		return -EINVAL;
 	if (ftrace_match_module_records(func, mod, enable))
 		return 0;
 	return -EINVAL;
 }
 static struct ftrace_func_command ftrace_mod_cmd = {
 	.name			= "mod",
 	.func			= ftrace_mod_callback,
 };
 static int __init ftrace_mod_cmd_init(void)
 {
 	return register_ftrace_command(&ftrace_mod_cmd);
 }
 device_initcall(ftrace_mod_cmd_init);
 static void
 function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
 {
 	struct ftrace_func_probe *entry;
 	struct hlist_head *hhd;
 	struct hlist_node *n;
 	unsigned long key;
 	int resched;
 	key = hash_long(ip, FTRACE_HASH_BITS);
 	hhd = &ftrace_func_hash[key];
 	if (hlist_empty(hhd))
 		return;
 	/*
 	 * Disable preemption for these calls to prevent a RCU grace
 	 * period. This syncs the hash iteration and freeing of items
 	 * on the hash. rcu_read_lock is too dangerous here.
 	 */
 	resched = ftrace_preempt_disable();
 	hlist_for_each_entry_rcu(entry, n, hhd, node) {
 		if (entry->ip == ip)
 			entry->ops->func(ip, parent_ip, &entry->data);
 	}
 	ftrace_preempt_enable(resched);
 }
 static struct ftrace_ops trace_probe_ops __read_mostly =
 {
 	.func		= function_trace_probe_call,
 };
 static int ftrace_probe_registered;
 static void __enable_ftrace_function_probe(void)
 {
 	int i;
 	if (ftrace_probe_registered)
 		return;
 	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
 		struct hlist_head *hhd = &ftrace_func_hash[i];
 		if (hhd->first)
 			break;
 	}
 	/* Nothing registered? */
 	if (i == FTRACE_FUNC_HASHSIZE)
 		return;
 	__register_ftrace_function(&trace_probe_ops);
 	ftrace_startup(0);
 	ftrace_probe_registered = 1;
 }
 static void __disable_ftrace_function_probe(void)
 {
 	int i;
 	if (!ftrace_probe_registered)
 		return;
 	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
 		struct hlist_head *hhd = &ftrace_func_hash[i];
 		if (hhd->first)
 			return;
 	}
 	/* no more funcs left */
 	__unregister_ftrace_function(&trace_probe_ops);
 	ftrace_shutdown(0);
 	ftrace_probe_registered = 0;
 }
 static void ftrace_free_entry_rcu(struct rcu_head *rhp)
 {
 	struct ftrace_func_probe *entry =
 		container_of(rhp, struct ftrace_func_probe, rcu);
 	if (entry->ops->free)
 		entry->ops->free(&entry->data);
 	kfree(entry);
 }
 int
 register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 			      void *data)
 {
 	struct ftrace_func_probe *entry;
 	struct ftrace_page *pg;
 	struct dyn_ftrace *rec;
 	int type, len, not;
 	unsigned long key;
 	int count = 0;
 	char *search;
 	type = filter_parse_regex(glob, strlen(glob), &search, &not);
 	len = strlen(search);
 	/* we do not support '!' for function probes */
 	if (WARN_ON(not))
 		return -EINVAL;
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->flags & FTRACE_FL_FAILED)
 			continue;
 		if (!ftrace_match_record(rec, search, len, type))
 			continue;
 		entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 		if (!entry) {
 			/* If we did not process any, then return error */
 			if (!count)
 				count = -ENOMEM;
 			goto out_unlock;
 		}
 		count++;
 		entry->data = data;
 		/*
 		 * The caller might want to do something special
 		 * for each function we find. We call the callback
 		 * to give the caller an opportunity to do so.
 		 */
 		if (ops->callback) {
 			if (ops->callback(rec->ip, &entry->data) < 0) {
 				/* caller does not like this func */
 				kfree(entry);
 				continue;
 			}
 		}
 		entry->ops = ops;
 		entry->ip = rec->ip;
 		key = hash_long(entry->ip, FTRACE_HASH_BITS);
 		hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
 	} while_for_each_ftrace_rec();
 	__enable_ftrace_function_probe();
  out_unlock:
 	mutex_unlock(&ftrace_lock);
 	return count;
 }
 enum {
 	PROBE_TEST_FUNC		= 1,
 	PROBE_TEST_DATA		= 2
 };
 static void
 __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 				  void *data, int flags)
 {
 	struct ftrace_func_probe *entry;
 	struct hlist_node *n, *tmp;
 	char str[KSYM_SYMBOL_LEN];
 	int type = MATCH_FULL;
 	int i, len = 0;
 	char *search;
 	if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
 		glob = NULL;
 	else if (glob) {
 		int not;
 		type = filter_parse_regex(glob, strlen(glob), &search, &not);
 		len = strlen(search);
 		/* we do not support '!' for function probes */
 		if (WARN_ON(not))
 			return;
 	}
 	mutex_lock(&ftrace_lock);
 	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
 		struct hlist_head *hhd = &ftrace_func_hash[i];
 		hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
 			/* break up if statements for readability */
 			if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
 				continue;
 			if ((flags & PROBE_TEST_DATA) && entry->data != data)
 				continue;
 			/* do this last, since it is the most expensive */
 			if (glob) {
 				kallsyms_lookup(entry->ip, NULL, NULL,
 						NULL, str);
 				if (!ftrace_match(str, glob, len, type))
 					continue;
 			}
 			hlist_del(&entry->node);
 			call_rcu(&entry->rcu, ftrace_free_entry_rcu);
 		}
 	}
 	__disable_ftrace_function_probe();
 	mutex_unlock(&ftrace_lock);
 }
 void
 unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 				void *data)
 {
 	__unregister_ftrace_function_probe(glob, ops, data,
 					  PROBE_TEST_FUNC | PROBE_TEST_DATA);
 }
 void
 unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
 {
 	__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
 }
 void unregister_ftrace_function_probe_all(char *glob)
 {
 	__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
 }
 static LIST_HEAD(ftrace_commands);
 static DEFINE_MUTEX(ftrace_cmd_mutex);
 int register_ftrace_command(struct ftrace_func_command *cmd)
 {
 	struct ftrace_func_command *p;
 	int ret = 0;
 	mutex_lock(&ftrace_cmd_mutex);
 	list_for_each_entry(p, &ftrace_commands, list) {
 		if (strcmp(cmd->name, p->name) == 0) {
 			ret = -EBUSY;
 			goto out_unlock;
 		}
 	}
 	list_add(&cmd->list, &ftrace_commands);
  out_unlock:
 	mutex_unlock(&ftrace_cmd_mutex);
 	return ret;
 }
 int unregister_ftrace_command(struct ftrace_func_command *cmd)
 {
 	struct ftrace_func_command *p, *n;
 	int ret = -ENODEV;
 	mutex_lock(&ftrace_cmd_mutex);
 	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
 		if (strcmp(cmd->name, p->name) == 0) {
 			ret = 0;
 			list_del_init(&p->list);
 			goto out_unlock;
 		}
 	}
  out_unlock:
 	mutex_unlock(&ftrace_cmd_mutex);
 	return ret;
 }
 static int ftrace_process_regex(char *buff, int len, int enable)
 {
 	char *func, *command, *next = buff;
 	struct ftrace_func_command *p;
 	int ret = -EINVAL;
 	func = strsep(&next, ":");
 	if (!next) {
 		if (ftrace_match_records(func, len, enable))
 			return 0;
 		return ret;
 	}
 	/* command found */
 	command = strsep(&next, ":");
 	mutex_lock(&ftrace_cmd_mutex);
 	list_for_each_entry(p, &ftrace_commands, list) {
 		if (strcmp(p->name, command) == 0) {
 			ret = p->func(func, command, next, enable);
 			goto out_unlock;
 		}
 	}
  out_unlock:
 	mutex_unlock(&ftrace_cmd_mutex);
 	return ret;
 }
 static ssize_t
 ftrace_regex_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos, int enable)
 {
 	struct ftrace_iterator *iter;
 	struct trace_parser *parser;
 	ssize_t ret, read;
 	if (!cnt)
 		return 0;
 	mutex_lock(&ftrace_regex_lock);
 	if (file->f_mode & FMODE_READ) {
 		struct seq_file *m = file->private_data;
 		iter = m->private;
 	} else
 		iter = file->private_data;
 	parser = &iter->parser;
 	read = trace_get_user(parser, ubuf, cnt, ppos);
 	if (read >= 0 && trace_parser_loaded(parser) &&
 	    !trace_parser_cont(parser)) {
 		ret = ftrace_process_regex(parser->buffer,
 					   parser->idx, enable);
 		trace_parser_clear(parser);
 		if (ret)
 			goto out_unlock;
 	}
 	ret = read;
 out_unlock:
 	mutex_unlock(&ftrace_regex_lock);
 	return ret;
 }
 static ssize_t
 ftrace_filter_write(struct file *file, const char __user *ubuf,
 		    size_t cnt, loff_t *ppos)
 {
 	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
 }
 static ssize_t
 ftrace_notrace_write(struct file *file, const char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
 	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
 }
 static void
 ftrace_set_regex(unsigned char *buf, int len, int reset, int enable)
 {
 	if (unlikely(ftrace_disabled))
 		return;
 	mutex_lock(&ftrace_regex_lock);
 	if (reset)
 		ftrace_filter_reset(enable);
 	if (buf)
 		ftrace_match_records(buf, len, enable);
 	mutex_unlock(&ftrace_regex_lock);
 }
 /**
  * ftrace_set_filter - set a function to filter on in ftrace
  * @buf - the string that holds the function filter text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Filters denote which functions should be enabled when tracing is enabled.
  * If @buf is NULL and reset is set, all functions will be enabled for tracing.
  */
 void ftrace_set_filter(unsigned char *buf, int len, int reset)
 {
 	ftrace_set_regex(buf, len, reset, 1);
 }
 /**
  * ftrace_set_notrace - set a function to not trace in ftrace
  * @buf - the string that holds the function notrace text.
  * @len - the length of the string.
  * @reset - non zero to reset all filters before applying this filter.
  *
  * Notrace Filters denote which functions should not be enabled when tracing
  * is enabled. If @buf is NULL and reset is set, all functions will be enabled
  * for tracing.
  */
 void ftrace_set_notrace(unsigned char *buf, int len, int reset)
 {
 	ftrace_set_regex(buf, len, reset, 0);
 }
 /*
  * command line interface to allow users to set filters on boot up.
  */
 #define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
 static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
 static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
 static int __init set_ftrace_notrace(char *str)
 {
 	strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_notrace=", set_ftrace_notrace);
 static int __init set_ftrace_filter(char *str)
 {
 	strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_filter=", set_ftrace_filter);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
 static int __init set_graph_function(char *str)
 {
 	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
 	return 1;
 }
 __setup("ftrace_graph_filter=", set_graph_function);
 static void __init set_ftrace_early_graph(char *buf)
 {
 	int ret;
 	char *func;
 	while (buf) {
 		func = strsep(&buf, ",");
 		/* we allow only one expression at a time */
 		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
 				      func);
 		if (ret)
 			printk(KERN_DEBUG "ftrace: function %s not "
 					  "traceable\n", func);
 	}
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 static void __init set_ftrace_early_filter(char *buf, int enable)
 {
 	char *func;
 	while (buf) {
 		func = strsep(&buf, ",");
 		ftrace_set_regex(func, strlen(func), 0, enable);
 	}
 }
 static void __init set_ftrace_early_filters(void)
 {
 	if (ftrace_filter_buf[0])
 		set_ftrace_early_filter(ftrace_filter_buf, 1);
 	if (ftrace_notrace_buf[0])
 		set_ftrace_early_filter(ftrace_notrace_buf, 0);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	if (ftrace_graph_buf[0])
 		set_ftrace_early_graph(ftrace_graph_buf);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 }
 static int
 ftrace_regex_release(struct inode *inode, struct file *file, int enable)
 {
 	struct seq_file *m = (struct seq_file *)file->private_data;
 	struct ftrace_iterator *iter;
 	struct trace_parser *parser;
 	mutex_lock(&ftrace_regex_lock);
 	if (file->f_mode & FMODE_READ) {
 		iter = m->private;
 		seq_release(inode, file);
 	} else
 		iter = file->private_data;
 	parser = &iter->parser;
 	if (trace_parser_loaded(parser)) {
 		parser->buffer[parser->idx] = 0;
 		ftrace_match_records(parser->buffer, parser->idx, enable);
 	}
 	mutex_lock(&ftrace_lock);
 	if (ftrace_start_up && ftrace_enabled)
 		ftrace_run_update_code(FTRACE_ENABLE_CALLS);
 	mutex_unlock(&ftrace_lock);
 	trace_parser_put(parser);
 	kfree(iter);
 	mutex_unlock(&ftrace_regex_lock);
 	return 0;
 }
 static int
 ftrace_filter_release(struct inode *inode, struct file *file)
 {
 	return ftrace_regex_release(inode, file, 1);
 }
 static int
 ftrace_notrace_release(struct inode *inode, struct file *file)
 {
 	return ftrace_regex_release(inode, file, 0);
 }
 static const struct file_operations ftrace_avail_fops = {
 	.open = ftrace_avail_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = seq_release_private,
 };
 static const struct file_operations ftrace_failures_fops = {
 	.open = ftrace_failures_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = seq_release_private,
 };
 static const struct file_operations ftrace_filter_fops = {
 	.open = ftrace_filter_open,
 	.read = seq_read,
 	.write = ftrace_filter_write,
 	.llseek = ftrace_regex_lseek,
 	.release = ftrace_filter_release,
 };
 static const struct file_operations ftrace_notrace_fops = {
 	.open = ftrace_notrace_open,
 	.read = seq_read,
 	.write = ftrace_notrace_write,
 	.llseek = ftrace_regex_lseek,
 	.release = ftrace_notrace_release,
 };
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static DEFINE_MUTEX(graph_lock);
 int ftrace_graph_count;
 int ftrace_graph_filter_enabled;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 static void *
 __g_next(struct seq_file *m, loff_t *pos)
 {
 	if (*pos >= ftrace_graph_count)
 		return NULL;
 	return &ftrace_graph_funcs[*pos];
 }
 static void *
 g_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	(*pos)++;
 	return __g_next(m, pos);
 }
 static void *g_start(struct seq_file *m, loff_t *pos)
 {
 	mutex_lock(&graph_lock);
 	/* Nothing, tell g_show to print all functions are enabled */
 	if (!ftrace_graph_filter_enabled && !*pos)
 		return (void *)1;
 	return __g_next(m, pos);
 }
 static void g_stop(struct seq_file *m, void *p)
 {
 	mutex_unlock(&graph_lock);
 }
 static int g_show(struct seq_file *m, void *v)
 {
 	unsigned long *ptr = v;
 	if (!ptr)
 		return 0;
 	if (ptr == (unsigned long *)1) {
 		seq_printf(m, "#### all functions enabled ####\n");
 		return 0;
 	}
 	seq_printf(m, "%ps\n", (void *)*ptr);
 	return 0;
 }
 static const struct seq_operations ftrace_graph_seq_ops = {
 	.start = g_start,
 	.next = g_next,
 	.stop = g_stop,
 	.show = g_show,
 };
 static int
 ftrace_graph_open(struct inode *inode, struct file *file)
 {
 	int ret = 0;
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 	mutex_lock(&graph_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC)) {
 		ftrace_graph_filter_enabled = 0;
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}
 	mutex_unlock(&graph_lock);
 	if (file->f_mode & FMODE_READ)
 		ret = seq_open(file, &ftrace_graph_seq_ops);
 	return ret;
 }
 static int
 ftrace_graph_release(struct inode *inode, struct file *file)
 {
 	if (file->f_mode & FMODE_READ)
 		seq_release(inode, file);
 	return 0;
 }
 static int
 ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 {
 	struct dyn_ftrace *rec;
 	struct ftrace_page *pg;
 	int search_len;
 	int fail = 1;
 	int type, not;
 	char *search;
 	bool exists;
 	int i;
 	if (ftrace_disabled)
 		return -ENODEV;
 	/* decode regex */
 	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
 	if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
 		return -EBUSY;
 	search_len = strlen(search);
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 		if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
 			continue;
 		if (ftrace_match_record(rec, search, search_len, type)) {
 			/* if it is in the array */
 			exists = false;
 			for (i = 0; i < *idx; i++) {
 				if (array[i] == rec->ip) {
 					exists = true;
 					break;
 				}
 			}
 			if (!not) {
 				fail = 0;
 				if (!exists) {
 					array[(*idx)++] = rec->ip;
 					if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
 						goto out;
 				}
 			} else {
 				if (exists) {
 					array[i] = array[--(*idx)];
 					array[*idx] = 0;
 					fail = 0;
 				}
 			}
 		}
 	} while_for_each_ftrace_rec();
 out:
 	mutex_unlock(&ftrace_lock);
 	if (fail)
 		return -EINVAL;
 	ftrace_graph_filter_enabled = 1;
 	return 0;
 }
 static ssize_t
 ftrace_graph_write(struct file *file, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
 	struct trace_parser parser;
 	ssize_t read, ret;
 	if (!cnt)
 		return 0;
 	mutex_lock(&graph_lock);
 	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
 		ret = -ENOMEM;
 		goto out_unlock;
 	}
 	read = trace_get_user(&parser, ubuf, cnt, ppos);
 	if (read >= 0 && trace_parser_loaded((&parser))) {
 		parser.buffer[parser.idx] = 0;
 		/* we allow only one expression at a time */
 		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
 					parser.buffer);
 		if (ret)
 			goto out_free;
 	}
 	ret = read;
 out_free:
 	trace_parser_put(&parser);
 out_unlock:
 	mutex_unlock(&graph_lock);
 	return ret;
 }
 static const struct file_operations ftrace_graph_fops = {
 	.open		= ftrace_graph_open,
 	.read		= seq_read,
 	.write		= ftrace_graph_write,
 	.release	= ftrace_graph_release,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 {
 	trace_create_file("available_filter_functions", 0444,
 			d_tracer, NULL, &ftrace_avail_fops);
 	trace_create_file("failures", 0444,
 			d_tracer, NULL, &ftrace_failures_fops);
 	trace_create_file("set_ftrace_filter", 0644, d_tracer,
 			NULL, &ftrace_filter_fops);
 	trace_create_file("set_ftrace_notrace", 0644, d_tracer,
 				    NULL, &ftrace_notrace_fops);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	trace_create_file("set_graph_function", 0444, d_tracer,
 				    NULL,
 				    &ftrace_graph_fops);
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 	return 0;
 }
 static int ftrace_process_locs(struct module *mod,
 			       unsigned long *start,
 			       unsigned long *end)
 {
 	unsigned long *p;
 	unsigned long addr;
 	unsigned long flags;
 	mutex_lock(&ftrace_lock);
 	p = start;
 	while (p < end) {
 		addr = ftrace_call_adjust(*p++);
 		/*
 		 * Some architecture linkers will pad between
 		 * the different mcount_loc sections of different
 		 * object files to satisfy alignments.
 		 * Skip any NULL pointers.
 		 */
 		if (!addr)
 			continue;
 		ftrace_record_ip(addr);
 	}
 	/* disable interrupts to prevent kstop machine */
 	local_irq_save(flags);
 	ftrace_update_code(mod);
 	local_irq_restore(flags);
 	mutex_unlock(&ftrace_lock);
 	return 0;
 }
 #ifdef CONFIG_MODULES
 void ftrace_release_mod(struct module *mod)
 {
 	struct dyn_ftrace *rec;
 	struct ftrace_page *pg;
 	if (ftrace_disabled)
 		return;
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 		if (within_module_core(rec->ip, mod)) {
 			/*
 			 * rec->ip is changed in ftrace_free_rec()
 			 * It should not between s and e if record was freed.
 			 */
 			FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
 			ftrace_free_rec(rec);
 		}
 	} while_for_each_ftrace_rec();
 	mutex_unlock(&ftrace_lock);
 }
 static void ftrace_init_module(struct module *mod,
 			       unsigned long *start, unsigned long *end)
 {
 	if (ftrace_disabled || start == end)
 		return;
 	ftrace_process_locs(mod, start, end);
 }
 static int ftrace_module_notify(struct notifier_block *self,
 				unsigned long val, void *data)
 {
 	struct module *mod = data;
 	switch (val) {
 	case MODULE_STATE_COMING:
 		ftrace_init_module(mod, mod->ftrace_callsites,
 				   mod->ftrace_callsites +
 				   mod->num_ftrace_callsites);
 		break;
 	case MODULE_STATE_GOING:
 		ftrace_release_mod(mod);
 		break;
 	}
 	return 0;
 }
 #else
 static int ftrace_module_notify(struct notifier_block *self,
 				unsigned long val, void *data)
 {
 	return 0;
 }
 #endif /* CONFIG_MODULES */
 struct notifier_block ftrace_module_nb = {
 	.notifier_call = ftrace_module_notify,
 	.priority = 0,
 };
 extern unsigned long __start_mcount_loc[];
 extern unsigned long __stop_mcount_loc[];
 void __init ftrace_init(void)
 {
 	unsigned long count, addr, flags;
 	int ret;
 	/* Keep the ftrace pointer to the stub */
 	addr = (unsigned long)ftrace_stub;
 	local_irq_save(flags);
 	ftrace_dyn_arch_init(&addr);
 	local_irq_restore(flags);
 	/* ftrace_dyn_arch_init places the return code in addr */
 	if (addr)
 		goto failed;
 	count = __stop_mcount_loc - __start_mcount_loc;
 	ret = ftrace_dyn_table_alloc(count);
 	if (ret)
 		goto failed;
 	last_ftrace_enabled = ftrace_enabled = 1;
 	ret = ftrace_process_locs(NULL,
 				  __start_mcount_loc,
 				  __stop_mcount_loc);
 	ret = register_module_notifier(&ftrace_module_nb);
 	if (ret)
 		pr_warning("Failed to register trace ftrace module notifier\n");
 	set_ftrace_early_filters();
 	return;
  failed:
 	ftrace_disabled = 1;
 }
 #else
 static int __init ftrace_nodyn_init(void)
 {
 	ftrace_enabled = 1;
 	return 0;
 }
 device_initcall(ftrace_nodyn_init);
 static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
 static inline void ftrace_startup_enable(int command) { }
 /* Keep as macros so we do not need to define the commands */
 # define ftrace_startup(command)	do { } while (0)
 # define ftrace_shutdown(command)	do { } while (0)
 # define ftrace_startup_sysctl()	do { } while (0)
 # define ftrace_shutdown_sysctl()	do { } while (0)
 #endif /* CONFIG_DYNAMIC_FTRACE */
 static void clear_ftrace_swapper(void)
 {
 	struct task_struct *p;
 	int cpu;
 	get_online_cpus();
 	for_each_online_cpu(cpu) {
 		p = idle_task(cpu);
 		clear_tsk_trace_trace(p);
 	}
 	put_online_cpus();
 }
 static void set_ftrace_swapper(void)
 {
 	struct task_struct *p;
 	int cpu;
 	get_online_cpus();
 	for_each_online_cpu(cpu) {
 		p = idle_task(cpu);
 		set_tsk_trace_trace(p);
 	}
 	put_online_cpus();
 }
 static void clear_ftrace_pid(struct pid *pid)
 {
 	struct task_struct *p;
 	rcu_read_lock();
 	do_each_pid_task(pid, PIDTYPE_PID, p) {
 		clear_tsk_trace_trace(p);
 	} while_each_pid_task(pid, PIDTYPE_PID, p);
 	rcu_read_unlock();
 	put_pid(pid);
 }
 static void set_ftrace_pid(struct pid *pid)
 {
 	struct task_struct *p;
 	rcu_read_lock();
 	do_each_pid_task(pid, PIDTYPE_PID, p) {
 		set_tsk_trace_trace(p);
 	} while_each_pid_task(pid, PIDTYPE_PID, p);
 	rcu_read_unlock();
 }
 static void clear_ftrace_pid_task(struct pid *pid)
 {
 	if (pid == ftrace_swapper_pid)
 		clear_ftrace_swapper();
 	else
 		clear_ftrace_pid(pid);
 }
 static void set_ftrace_pid_task(struct pid *pid)
 {
 	if (pid == ftrace_swapper_pid)
 		set_ftrace_swapper();
 	else
 		set_ftrace_pid(pid);
 }
 static int ftrace_pid_add(int p)
 {
 	struct pid *pid;
 	struct ftrace_pid *fpid;
 	int ret = -EINVAL;
 	mutex_lock(&ftrace_lock);
 	if (!p)
 		pid = ftrace_swapper_pid;
 	else
 		pid = find_get_pid(p);
 	if (!pid)
 		goto out;
 	ret = 0;
 	list_for_each_entry(fpid, &ftrace_pids, list)
 		if (fpid->pid == pid)
 			goto out_put;
 	ret = -ENOMEM;
 	fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
 	if (!fpid)
 		goto out_put;
 	list_add(&fpid->list, &ftrace_pids);
 	fpid->pid = pid;
 	set_ftrace_pid_task(pid);
 	ftrace_update_pid_func();
 	ftrace_startup_enable(0);
 	mutex_unlock(&ftrace_lock);
 	return 0;
 out_put:
 	if (pid != ftrace_swapper_pid)
 		put_pid(pid);
 out:
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
 static void ftrace_pid_reset(void)
 {
 	struct ftrace_pid *fpid, *safe;
 	mutex_lock(&ftrace_lock);
 	list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
 		struct pid *pid = fpid->pid;
 		clear_ftrace_pid_task(pid);
 		list_del(&fpid->list);
 		kfree(fpid);
 	}
 	ftrace_update_pid_func();
 	ftrace_startup_enable(0);
 	mutex_unlock(&ftrace_lock);
 }
 static void *fpid_start(struct seq_file *m, loff_t *pos)
 {
 	mutex_lock(&ftrace_lock);
 	if (list_empty(&ftrace_pids) && (!*pos))
 		return (void *) 1;
 	return seq_list_start(&ftrace_pids, *pos);
 }
 static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	if (v == (void *)1)
 		return NULL;
 	return seq_list_next(v, &ftrace_pids, pos);
 }
 static void fpid_stop(struct seq_file *m, void *p)
 {
 	mutex_unlock(&ftrace_lock);
 }
 static int fpid_show(struct seq_file *m, void *v)
 {
 	const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
 	if (v == (void *)1) {
 		seq_printf(m, "no pid\n");
 		return 0;
 	}
 	if (fpid->pid == ftrace_swapper_pid)
 		seq_printf(m, "swapper tasks\n");
 	else
 		seq_printf(m, "%u\n", pid_vnr(fpid->pid));
 	return 0;
 }
 static const struct seq_operations ftrace_pid_sops = {
 	.start = fpid_start,
 	.next = fpid_next,
 	.stop = fpid_stop,
 	.show = fpid_show,
 };
 static int
 ftrace_pid_open(struct inode *inode, struct file *file)
 {
 	int ret = 0;
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC))
 		ftrace_pid_reset();
 	if (file->f_mode & FMODE_READ)
 		ret = seq_open(file, &ftrace_pid_sops);
 	return ret;
 }
 static ssize_t
 ftrace_pid_write(struct file *filp, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
 	char buf[64], *tmp;
 	long val;
 	int ret;
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;
 	buf[cnt] = 0;
 	/*
 	 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
 	 * to clean the filter quietly.
 	 */
 	tmp = strstrip(buf);
 	if (strlen(tmp) == 0)
 		return 1;
 	ret = strict_strtol(tmp, 10, &val);
 	if (ret < 0)
 		return ret;
 	ret = ftrace_pid_add(val);
 	return ret ? ret : cnt;
 }
 static int
 ftrace_pid_release(struct inode *inode, struct file *file)
 {
 	if (file->f_mode & FMODE_READ)
 		seq_release(inode, file);
 	return 0;
 }
 static const struct file_operations ftrace_pid_fops = {
 	.open		= ftrace_pid_open,
 	.write		= ftrace_pid_write,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= ftrace_pid_release,
 };
 static __init int ftrace_init_debugfs(void)
 {
 	struct dentry *d_tracer;
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
 		return 0;
 	ftrace_init_dyn_debugfs(d_tracer);
 	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);
 /**
  * ftrace_kill - kill ftrace
  *
  * This function should be used by panic code. It stops ftrace
  * but in a not so nice way. If you need to simply kill ftrace
  * from a non-atomic section, use ftrace_kill.
  */
 void ftrace_kill(void)
 {
 	ftrace_disabled = 1;
 	ftrace_enabled = 0;
 	clear_ftrace_function();
 }
 /**
  * register_ftrace_function - register a function for profiling
  * @ops - ops structure that holds the function for profiling.
  *
  * Register a function to be called by all functions in the
  * kernel.
  *
  * Note: @ops->func and all the functions it calls must be labeled
  *       with "notrace", otherwise it will go into a
  *       recursive loop.
  */
 int register_ftrace_function(struct ftrace_ops *ops)
 {
 	int ret;
 	if (unlikely(ftrace_disabled))
 		return -1;
 	mutex_lock(&ftrace_lock);
 	ret = __register_ftrace_function(ops);
 	ftrace_startup(0);
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
 /**
  * unregister_ftrace_function - unregister a function for profiling.
  * @ops - ops structure that holds the function to unregister
  *
  * Unregister a function that was added to be called by ftrace profiling.
  */
 int unregister_ftrace_function(struct ftrace_ops *ops)
 {
 	int ret;
 	mutex_lock(&ftrace_lock);
 	ret = __unregister_ftrace_function(ops);
 	ftrace_shutdown(0);
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
 int
 ftrace_enable_sysctl(struct ctl_table *table, int write,
 		     void __user *buffer, size_t *lenp,
 		     loff_t *ppos)
 {
 	int ret;
 	if (unlikely(ftrace_disabled))
 		return -ENODEV;
 	mutex_lock(&ftrace_lock);
 	ret  = proc_dointvec(table, write, buffer, lenp, ppos);
 	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
 		goto out;
 	last_ftrace_enabled = !!ftrace_enabled;
 	if (ftrace_enabled) {
 		ftrace_startup_sysctl();
 		/* we are starting ftrace again */
 		if (ftrace_list != &ftrace_list_end) {
 			if (ftrace_list->next == &ftrace_list_end)
 				ftrace_trace_function = ftrace_list->func;
 			else
 				ftrace_trace_function = ftrace_list_func;
 		}
 	} else {
 		/* stopping ftrace calls (just send to ftrace_stub) */
 		ftrace_trace_function = ftrace_stub;
 		ftrace_shutdown_sysctl();
 	}
  out:
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static int ftrace_graph_active;
 static struct notifier_block ftrace_suspend_notifier;
 int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
 {
 	return 0;
 }
 /* The callbacks that hook a function */
 trace_func_graph_ret_t ftrace_graph_return =
 			(trace_func_graph_ret_t)ftrace_stub;
 trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
 static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
 {
 	int i;
 	int ret = 0;
 	unsigned long flags;
 	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
 	struct task_struct *g, *t;
 	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
 		ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
 					* sizeof(struct ftrace_ret_stack),
 					GFP_KERNEL);
 		if (!ret_stack_list[i]) {
 			start = 0;
 			end = i;
 			ret = -ENOMEM;
 			goto free;
 		}
 	}
 	read_lock_irqsave(&tasklist_lock, flags);
 	do_each_thread(g, t) {
 		if (start == end) {
 			ret = -EAGAIN;
 			goto unlock;
 		}
 		if (t->ret_stack == NULL) {
 			atomic_set(&t->tracing_graph_pause, 0);
 			atomic_set(&t->trace_overrun, 0);
 			t->curr_ret_stack = -1;
 			/* Make sure the tasks see the -1 first: */
 			smp_wmb();
 			t->ret_stack = ret_stack_list[start++];
 		}
 	} while_each_thread(g, t);
 unlock:
 	read_unlock_irqrestore(&tasklist_lock, flags);
 free:
 	for (i = start; i < end; i++)
 		kfree(ret_stack_list[i]);
 	return ret;
 }
 static void
 ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 				struct task_struct *next)
 {
 	unsigned long long timestamp;
 	int index;
 	/*
 	 * Does the user want to count the time a function was asleep.
 	 * If so, do not update the time stamps.
 	 */
 	if (trace_flags & TRACE_ITER_SLEEP_TIME)
 		return;
 	timestamp = trace_clock_local();
 	prev->ftrace_timestamp = timestamp;
 	/* only process tasks that we timestamped */
 	if (!next->ftrace_timestamp)
 		return;
 	/*
 	 * Update all the counters in next to make up for the
 	 * time next was sleeping.
 	 */
 	timestamp -= next->ftrace_timestamp;
 	for (index = next->curr_ret_stack; index >= 0; index--)
 		next->ret_stack[index].calltime += timestamp;
 }
 /* Allocate a return stack for each task */
 static int start_graph_tracing(void)
 {
 	struct ftrace_ret_stack **ret_stack_list;
 	int ret, cpu;
 	ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
 				sizeof(struct ftrace_ret_stack *),
 				GFP_KERNEL);
 	if (!ret_stack_list)
 		return -ENOMEM;
 	/* The cpu_boot init_task->ret_stack will never be freed */
 	for_each_online_cpu(cpu) {
 		if (!idle_task(cpu)->ret_stack)
 			ftrace_graph_init_task(idle_task(cpu));
 	}
 	do {
 		ret = alloc_retstack_tasklist(ret_stack_list);
 	} while (ret == -EAGAIN);
 	if (!ret) {
 		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
 		if (ret)
 			pr_info("ftrace_graph: Couldn't activate tracepoint"
 				" probe to kernel_sched_switch\n");
 	}
 	kfree(ret_stack_list);
 	return ret;
 }
 /*
  * Hibernation protection.
  * The state of the current task is too much unstable during
  * suspend/restore to disk. We want to protect against that.
  */
 static int
 ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
 							void *unused)
 {
 	switch (state) {
 	case PM_HIBERNATION_PREPARE:
 		pause_graph_tracing();
 		break;
 	case PM_POST_HIBERNATION:
 		unpause_graph_tracing();
 		break;
 	}
 	return NOTIFY_DONE;
 }
 int register_ftrace_graph(trace_func_graph_ret_t retfunc,
 			trace_func_graph_ent_t entryfunc)
 {
 	int ret = 0;
 	mutex_lock(&ftrace_lock);
 	/* we currently allow only one tracer registered at a time */
 	if (ftrace_graph_active) {
 		ret = -EBUSY;
 		goto out;
 	}
 	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
 	register_pm_notifier(&ftrace_suspend_notifier);
 	ftrace_graph_active++;
 	ret = start_graph_tracing();
 	if (ret) {
 		ftrace_graph_active--;
 		goto out;
 	}
 	ftrace_graph_return = retfunc;
 	ftrace_graph_entry = entryfunc;
 	ftrace_startup(FTRACE_START_FUNC_RET);
 out:
 	mutex_unlock(&ftrace_lock);
 	return ret;
 }
 void unregister_ftrace_graph(void)
 {
 	mutex_lock(&ftrace_lock);
 	if (unlikely(!ftrace_graph_active))
 		goto out;
 	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;
 	ftrace_shutdown(FTRACE_STOP_FUNC_RET);
 	unregister_pm_notifier(&ftrace_suspend_notifier);
  out:
 	mutex_unlock(&ftrace_lock);
 }
 /* Allocate a return stack for newly created task */
 void ftrace_graph_init_task(struct task_struct *t)
 {
 	/* Make sure we do not use the parent ret_stack */
 	t->ret_stack = NULL;
 	if (ftrace_graph_active) {
 		struct ftrace_ret_stack *ret_stack;
 		ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
 				* sizeof(struct ftrace_ret_stack),
 				GFP_KERNEL);
 		if (!ret_stack)
 			return;
 		t->curr_ret_stack = -1;
 		atomic_set(&t->tracing_graph_pause, 0);
 		atomic_set(&t->trace_overrun, 0);
 		t->ftrace_timestamp = 0;
 		/* make curr_ret_stack visable before we add the ret_stack */
 		smp_wmb();
 		t->ret_stack = ret_stack;
 	}
 }
 void ftrace_graph_exit_task(struct task_struct *t)
 {
 	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
 	t->ret_stack = NULL;
 	/* NULL must become visible to IRQs before we free it: */
 	barrier();
 	kfree(ret_stack);
 }
 void ftrace_graph_stop(void)
 {
 	ftrace_stop();
 }

kernel/trace/trace.c

Diff comments View file @ 915a0b5

 /*
  * ring buffer based function tracer
  *
  * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
  * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
  *
  * Originally taken from the RT patch by:
  *    Arnaldo Carvalho de Melo <acme@redhat.com>
  *
  * Based on code from the latency_tracer, that is:
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 William Lee Irwin III
  */
 #include <linux/ring_buffer.h>
 #include <generated/utsrelease.h>
 #include <linux/stacktrace.h>
 #include <linux/writeback.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
 #include <linux/smp_lock.h>
 #include <linux/notifier.h>
 #include <linux/irqflags.h>
 #include <linux/debugfs.h>
 #include <linux/pagemap.h>
 #include <linux/hardirq.h>
 #include <linux/linkage.h>
 #include <linux/uaccess.h>
 #include <linux/kprobes.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/percpu.h>
 #include <linux/splice.h>
 #include <linux/kdebug.h>
 #include <linux/string.h>
 #include <linux/rwsem.h>
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/poll.h>
 #include <linux/gfp.h>
 #include <linux/fs.h>
 #include "trace.h"
 #include "trace_output.h"
 #define TRACE_BUFFER_FLAGS	(RB_FL_OVERWRITE)
 /*
  * 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.
  */
 int ring_buffer_expanded;
 /*
  * We need to change this state when a selftest is running.
  * A selftest will lurk into the ring-buffer to count the
  * entries inserted during the selftest although some concurrent
  * insertions into the ring-buffer such as trace_printk could occurred
  * at the same time, giving false positive or negative results.
  */
 static bool __read_mostly tracing_selftest_running;
 /*
  * If a tracer is running, we do not want to run SELFTEST.
  */
 bool __read_mostly tracing_selftest_disabled;
 /* For tracers that don't implement custom flags */
 static struct tracer_opt dummy_tracer_opt[] = {
 	{ }
 };
 static struct tracer_flags dummy_tracer_flags = {
 	.val = 0,
 	.opts = dummy_tracer_opt
 };
 static int dummy_set_flag(u32 old_flags, u32 bit, int set)
 {
 	return 0;
 }
 /*
  * Kill all tracing for good (never come back).
  * It is initialized to 1 but will turn to zero if the initialization
  * of the tracer is successful. But that is the only place that sets
  * this back to zero.
  */
 static int tracing_disabled = 1;
 DEFINE_PER_CPU(int, ftrace_cpu_disabled);
 static inline void ftrace_disable_cpu(void)
 {
 	preempt_disable();
 	__this_cpu_inc(per_cpu_var(ftrace_cpu_disabled));
 }
 static inline void ftrace_enable_cpu(void)
 {
 	__this_cpu_dec(per_cpu_var(ftrace_cpu_disabled));
 	preempt_enable();
 }
 static cpumask_var_t __read_mostly	tracing_buffer_mask;
 #define for_each_tracing_cpu(cpu)	\
 	for_each_cpu(cpu, tracing_buffer_mask)
 /*
  * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
  *
  * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
  * is set, then ftrace_dump is called. This will output the contents
  * of the ftrace buffers to the console.  This is very useful for
  * capturing traces that lead to crashes and outputing it to a
  * serial console.
  *
  * It is default off, but you can enable it with either specifying
  * "ftrace_dump_on_oops" in the kernel command line, or setting
  * /proc/sys/kernel/ftrace_dump_on_oops to true.
  */
 int ftrace_dump_on_oops;
 static int tracing_set_tracer(const char *buf);
 #define MAX_TRACER_SIZE		100
 static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
 static char *default_bootup_tracer;
 static int __init set_cmdline_ftrace(char *str)
 {
 	strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
 	default_bootup_tracer = bootup_tracer_buf;
 	/* We are using ftrace early, expand it */
 	ring_buffer_expanded = 1;
 	return 1;
 }
 __setup("ftrace=", set_cmdline_ftrace);
 static int __init set_ftrace_dump_on_oops(char *str)
 {
 	ftrace_dump_on_oops = 1;
 	return 1;
 }
 __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
 unsigned long long ns2usecs(cycle_t nsec)
 {
 	nsec += 500;
 	do_div(nsec, 1000);
 	return nsec;
 }
 /*
  * The global_trace is the descriptor that holds the tracing
  * buffers for the live tracing. For each CPU, it contains
  * a link list of pages that will store trace entries. The
  * page descriptor of the pages in the memory is used to hold
  * the link list by linking the lru item in the page descriptor
  * to each of the pages in the buffer per CPU.
  *
  * For each active CPU there is a data field that holds the
  * pages for the buffer for that CPU. Each CPU has the same number
  * of pages allocated for its buffer.
  */
 static struct trace_array	global_trace;
 static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
 int filter_current_check_discard(struct ring_buffer *buffer,
 				 struct ftrace_event_call *call, void *rec,
 				 struct ring_buffer_event *event)
 {
 	return filter_check_discard(call, rec, buffer, event);
 }
 EXPORT_SYMBOL_GPL(filter_current_check_discard);
 cycle_t ftrace_now(int cpu)
 {
 	u64 ts;
 	/* Early boot up does not have a buffer yet */
 	if (!global_trace.buffer)
 		return trace_clock_local();
 	ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
 	ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
 	return ts;
 }
 /*
  * The max_tr is used to snapshot the global_trace when a maximum
  * latency is reached. Some tracers will use this to store a maximum
  * trace while it continues examining live traces.
  *
  * The buffers for the max_tr are set up the same as the global_trace.
  * When a snapshot is taken, the link list of the max_tr is swapped
  * with the link list of the global_trace and the buffers are reset for
  * the global_trace so the tracing can continue.
  */
 static struct trace_array	max_tr;
 static DEFINE_PER_CPU(struct trace_array_cpu, max_tr_data);
 /* tracer_enabled is used to toggle activation of a tracer */
 static int			tracer_enabled = 1;
 /**
  * tracing_is_enabled - return tracer_enabled status
  *
  * This function is used by other tracers to know the status
  * of the tracer_enabled flag.  Tracers may use this function
  * to know if it should enable their features when starting
  * up. See irqsoff tracer for an example (start_irqsoff_tracer).
  */
 int tracing_is_enabled(void)
 {
 	return tracer_enabled;
 }
 /*
  * trace_buf_size is the size in bytes that is allocated
  * for a buffer. Note, the number of bytes is always rounded
  * to page size.
  *
  * This number is purposely set to a low number of 16384.
  * If the dump on oops happens, it will be much appreciated
  * to not have to wait for all that output. Anyway this can be
  * boot time and run time configurable.
  */
 #define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
 static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
 /* trace_types holds a link list of available tracers. */
 static struct tracer		*trace_types __read_mostly;
 /* current_trace points to the tracer that is currently active */
 static struct tracer		*current_trace __read_mostly;
 /*
  * trace_types_lock is used to protect the trace_types list.
  */
 static DEFINE_MUTEX(trace_types_lock);
 /*
  * serialize the access of the ring buffer
  *
  * ring buffer serializes readers, but it is low level protection.
  * The validity of the events (which returns by ring_buffer_peek() ..etc)
  * are not protected by ring buffer.
  *
  * The content of events may become garbage if we allow other process consumes
  * these events concurrently:
  *   A) the page of the consumed events may become a normal page
  *      (not reader page) in ring buffer, and this page will be rewrited
  *      by events producer.
  *   B) The page of the consumed events may become a page for splice_read,
  *      and this page will be returned to system.
  *
  * These primitives allow multi process access to different cpu ring buffer
  * concurrently.
  *
  * These primitives don't distinguish read-only and read-consume access.
  * Multi read-only access are also serialized.
  */
 #ifdef CONFIG_SMP
 static DECLARE_RWSEM(all_cpu_access_lock);
 static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
 static inline void trace_access_lock(int cpu)
 {
 	if (cpu == TRACE_PIPE_ALL_CPU) {
 		/* gain it for accessing the whole ring buffer. */
 		down_write(&all_cpu_access_lock);
 	} else {
 		/* gain it for accessing a cpu ring buffer. */
 		/* Firstly block other trace_access_lock(TRACE_PIPE_ALL_CPU). */
 		down_read(&all_cpu_access_lock);
 		/* Secondly block other access to this @cpu ring buffer. */
 		mutex_lock(&per_cpu(cpu_access_lock, cpu));
 	}
 }
 static inline void trace_access_unlock(int cpu)
 {
 	if (cpu == TRACE_PIPE_ALL_CPU) {
 		up_write(&all_cpu_access_lock);
 	} else {
 		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
 		up_read(&all_cpu_access_lock);
 	}
 }
 static inline void trace_access_lock_init(void)
 {
 	int cpu;
 	for_each_possible_cpu(cpu)
 		mutex_init(&per_cpu(cpu_access_lock, cpu));
 }
 #else
 static DEFINE_MUTEX(access_lock);
 static inline void trace_access_lock(int cpu)
 {
 	(void)cpu;
 	mutex_lock(&access_lock);
 }
 static inline void trace_access_unlock(int cpu)
 {
 	(void)cpu;
 	mutex_unlock(&access_lock);
 }
 static inline void trace_access_lock_init(void)
 {
 }
 #endif
 /* trace_wait is a waitqueue for tasks blocked on trace_poll */
 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_GRAPH_TIME;
 static int trace_stop_count;
 static DEFINE_SPINLOCK(tracing_start_lock);
 /**
  * trace_wake_up - wake up tasks waiting for trace input
  *
  * Simply wakes up any task that is blocked on the trace_wait
  * queue. These is used with trace_poll for tasks polling the trace.
  */
 void trace_wake_up(void)
 {
 	int cpu;
 	if (trace_flags & TRACE_ITER_BLOCK)
 		return;
 	/*
 	 * The runqueue_is_locked() can fail, but this is the best we
 	 * have for now:
 	 */
 	cpu = get_cpu();
 	if (!runqueue_is_locked(cpu))
 		wake_up(&trace_wait);
 	put_cpu();
 }
 static int __init set_buf_size(char *str)
 {
 	unsigned long buf_size;
 	if (!str)
 		return 0;
 	buf_size = memparse(str, &str);
 	/* nr_entries can not be zero */
 	if (buf_size == 0)
 		return 0;
 	trace_buf_size = buf_size;
 	return 1;
 }
 __setup("trace_buf_size=", set_buf_size);
+static int __init set_tracing_thresh(char *str)
+{
+	unsigned long threshhold;
+	int ret;
+	if (!str)
+		return 0;
+	ret = strict_strtoul(str, 0, &threshhold);
+	if (ret < 0)
+		return 0;
+	tracing_thresh = threshhold * 1000;
+	return 1;
+}
+__setup("tracing_thresh=", set_tracing_thresh);
 unsigned long nsecs_to_usecs(unsigned long nsecs)
 {
 	return nsecs / 1000;
 }
 /* These must match the bit postions in trace_iterator_flags */
 static const char *trace_options[] = {
 	"print-parent",
 	"sym-offset",
 	"sym-addr",
 	"verbose",
 	"raw",
 	"hex",
 	"bin",
 	"block",
 	"stacktrace",
 	"trace_printk",
 	"ftrace_preempt",
 	"branch",
 	"annotate",
 	"userstacktrace",
 	"sym-userobj",
 	"printk-msg-only",
 	"context-info",
 	"latency-format",
 	"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;
 /*
  * trace_parser_get_init - gets the buffer for trace parser
  */
 int trace_parser_get_init(struct trace_parser *parser, int size)
 {
 	memset(parser, 0, sizeof(*parser));
 	parser->buffer = kmalloc(size, GFP_KERNEL);
 	if (!parser->buffer)
 		return 1;
 	parser->size = size;
 	return 0;
 }
 /*
  * trace_parser_put - frees the buffer for trace parser
  */
 void trace_parser_put(struct trace_parser *parser)
 {
 	kfree(parser->buffer);
 }
 /*
  * trace_get_user - reads the user input string separated by  space
  * (matched by isspace(ch))
  *
  * For each string found the 'struct trace_parser' is updated,
  * and the function returns.
  *
  * Returns number of bytes read.
  *
  * See kernel/trace/trace.h for 'struct trace_parser' details.
  */
 int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 	size_t cnt, loff_t *ppos)
 {
 	char ch;
 	size_t read = 0;
 	ssize_t ret;
 	if (!*ppos)
 		trace_parser_clear(parser);
 	ret = get_user(ch, ubuf++);
 	if (ret)
 		goto out;
 	read++;
 	cnt--;
 	/*
 	 * The parser is not finished with the last write,
 	 * continue reading the user input without skipping spaces.
 	 */
 	if (!parser->cont) {
 		/* skip white space */
 		while (cnt && isspace(ch)) {
 			ret = get_user(ch, ubuf++);
 			if (ret)
 				goto out;
 			read++;
 			cnt--;
 		}
 		/* only spaces were written */
 		if (isspace(ch)) {
 			*ppos += read;
 			ret = read;
 			goto out;
 		}
 		parser->idx = 0;
 	}
 	/* read the non-space input */
 	while (cnt && !isspace(ch)) {
 		if (parser->idx < parser->size - 1)
 			parser->buffer[parser->idx++] = ch;
 		else {
 			ret = -EINVAL;
 			goto out;
 		}
 		ret = get_user(ch, ubuf++);
 		if (ret)
 			goto out;
 		read++;
 		cnt--;
 	}
 	/* We either got finished input or we have to wait for another call. */
 	if (isspace(ch)) {
 		parser->buffer[parser->idx] = 0;
 		parser->cont = false;
 	} else {
 		parser->cont = true;
 		parser->buffer[parser->idx++] = ch;
 	}
 	*ppos += read;
 	ret = read;
 out:
 	return ret;
 }
 ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
 {
 	int len;
 	int ret;
 	if (!cnt)
 		return 0;
 	if (s->len <= s->readpos)
 		return -EBUSY;
 	len = s->len - s->readpos;
 	if (cnt > len)
 		cnt = len;
 	ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
 	if (ret == cnt)
 		return -EFAULT;
 	cnt -= ret;
 	s->readpos += cnt;
 	return cnt;
 }
 static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
 {
 	int len;
 	void *ret;
 	if (s->len <= s->readpos)
 		return -EBUSY;
 	len = s->len - s->readpos;
 	if (cnt > len)
 		cnt = len;
 	ret = memcpy(buf, s->buffer + s->readpos, cnt);
 	if (!ret)
 		return -EFAULT;
 	s->readpos += cnt;
 	return cnt;
 }
 /*
  * ftrace_max_lock is used to protect the swapping of buffers
  * when taking a max snapshot. The buffers themselves are
  * protected by per_cpu spinlocks. But the action of the swap
  * needs its own lock.
  *
  * This is defined as a arch_spinlock_t in order to help
  * with performance when lockdep debugging is enabled.
  *
  * It is also used in other places outside the update_max_tr
  * so it needs to be defined outside of the
  * CONFIG_TRACER_MAX_TRACE.
  */
 static arch_spinlock_t ftrace_max_lock =
 	(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+unsigned long __read_mostly	tracing_thresh;
 #ifdef CONFIG_TRACER_MAX_TRACE
 unsigned long __read_mostly	tracing_max_latency;
-unsigned long __read_mostly	tracing_thresh;
 /*
  * Copy the new maximum trace into the separate maximum-trace
  * structure. (this way the maximum trace is permanently saved,
  * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
  */
 static void
 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
 	struct trace_array_cpu *data = tr->data[cpu];
-	struct trace_array_cpu *max_data = tr->data[cpu];
+	struct trace_array_cpu *max_data;
 	max_tr.cpu = cpu;
 	max_tr.time_start = data->preempt_timestamp;
 	max_data = max_tr.data[cpu];
 	max_data->saved_latency = tracing_max_latency;
 	max_data->critical_start = data->critical_start;
 	max_data->critical_end = data->critical_end;
-	memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
+	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
 	max_data->pid = tsk->pid;
 	max_data->uid = task_uid(tsk);
 	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
 	max_data->policy = tsk->policy;
 	max_data->rt_priority = tsk->rt_priority;
 	/* record this tasks comm */
 	tracing_record_cmdline(tsk);
 }
 /**
  * update_max_tr - snapshot all trace buffers from global_trace to max_tr
  * @tr: tracer
  * @tsk: the task with the latency
  * @cpu: The cpu that initiated the trace.
  *
  * Flip the buffers between the @tr and the max_tr and record information
  * about which task was the cause of this latency.
  */
 void
 update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
 	struct ring_buffer *buf = tr->buffer;
 	if (trace_stop_count)
 		return;
 	WARN_ON_ONCE(!irqs_disabled());
 	arch_spin_lock(&ftrace_max_lock);
 	tr->buffer = max_tr.buffer;
 	max_tr.buffer = buf;
 	__update_max_tr(tr, tsk, cpu);
 	arch_spin_unlock(&ftrace_max_lock);
 }
 /**
  * update_max_tr_single - only copy one trace over, and reset the rest
  * @tr - tracer
  * @tsk - task with the latency
  * @cpu - the cpu of the buffer to copy.
  *
  * Flip the trace of a single CPU buffer between the @tr and the max_tr.
  */
 void
 update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 {
 	int ret;
 	if (trace_stop_count)
 		return;
 	WARN_ON_ONCE(!irqs_disabled());
 	arch_spin_lock(&ftrace_max_lock);
 	ftrace_disable_cpu();
 	ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
 	if (ret == -EBUSY) {
 		/*
 		 * We failed to swap the buffer due to a commit taking
 		 * place on this CPU. We fail to record, but we reset
 		 * the max trace buffer (no one writes directly to it)
 		 * and flag that it failed.
 		 */
 		trace_array_printk(&max_tr, _THIS_IP_,
 			"Failed to swap buffers due to commit in progress\n");
 	}
 	ftrace_enable_cpu();
 	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
 	__update_max_tr(tr, tsk, cpu);
 	arch_spin_unlock(&ftrace_max_lock);
 }
 #endif /* CONFIG_TRACER_MAX_TRACE */
 /**
  * register_tracer - register a tracer with the ftrace system.
  * @type - the plugin for the tracer
  *
  * Register a new plugin tracer.
  */
 int register_tracer(struct tracer *type)
 __releases(kernel_lock)
 __acquires(kernel_lock)
 {
 	struct tracer *t;
 	int ret = 0;
 	if (!type->name) {
 		pr_info("Tracer must have a name\n");
 		return -1;
 	}
 	if (strlen(type->name) > MAX_TRACER_SIZE) {
 		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
 		return -1;
 	}
 	/*
 	 * When this gets called we hold the BKL which means that
 	 * preemption is disabled. Various trace selftests however
 	 * need to disable and enable preemption for successful tests.
 	 * So we drop the BKL here and grab it after the tests again.
 	 */
 	unlock_kernel();
 	mutex_lock(&trace_types_lock);
 	tracing_selftest_running = true;
 	for (t = trace_types; t; t = t->next) {
 		if (strcmp(type->name, t->name) == 0) {
 			/* already found */
 			pr_info("Tracer %s already registered\n",
 				type->name);
 			ret = -1;
 			goto out;
 		}
 	}
 	if (!type->set_flag)
 		type->set_flag = &dummy_set_flag;
 	if (!type->flags)
 		type->flags = &dummy_tracer_flags;
 	else
 		if (!type->flags->opts)
 			type->flags->opts = dummy_tracer_opt;
 	if (!type->wait_pipe)
 		type->wait_pipe = default_wait_pipe;
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 	if (type->selftest && !tracing_selftest_disabled) {
 		struct tracer *saved_tracer = current_trace;
 		struct trace_array *tr = &global_trace;
 		/*
 		 * Run a selftest on this tracer.
 		 * Here we reset the trace buffer, and set the current
 		 * tracer to be this tracer. The tracer can then run some
 		 * internal tracing to verify that everything is in order.
 		 * If we fail, we do not register this tracer.
 		 */
 		tracing_reset_online_cpus(tr);
 		current_trace = type;
 		/* the test is responsible for initializing and enabling */
 		pr_info("Testing tracer %s: ", type->name);
 		ret = type->selftest(type, tr);
 		/* the test is responsible for resetting too */
 		current_trace = saved_tracer;
 		if (ret) {
 			printk(KERN_CONT "FAILED!\n");
 			goto out;
 		}
 		/* Only reset on passing, to avoid touching corrupted buffers */
 		tracing_reset_online_cpus(tr);
 		printk(KERN_CONT "PASSED\n");
 	}
 #endif
 	type->next = trace_types;
 	trace_types = type;
  out:
 	tracing_selftest_running = false;
 	mutex_unlock(&trace_types_lock);
 	if (ret || !default_bootup_tracer)
 		goto out_unlock;
 	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
 		goto out_unlock;
 	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
 	/* Do we want this tracer to start on bootup? */
 	tracing_set_tracer(type->name);
 	default_bootup_tracer = NULL;
 	/* disable other selftests, since this will break it. */
 	tracing_selftest_disabled = 1;
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
 	       type->name);
 #endif
  out_unlock:
 	lock_kernel();
 	return ret;
 }
 void unregister_tracer(struct tracer *type)
 {
 	struct tracer **t;
 	mutex_lock(&trace_types_lock);
 	for (t = &trace_types; *t; t = &(*t)->next) {
 		if (*t == type)
 			goto found;
 	}
 	pr_info("Tracer %s not registered\n", type->name);
 	goto out;
  found:
 	*t = (*t)->next;
 	if (type == current_trace && tracer_enabled) {
 		tracer_enabled = 0;
 		tracing_stop();
 		if (current_trace->stop)
 			current_trace->stop(&global_trace);
 		current_trace = &nop_trace;
 	}
 out:
 	mutex_unlock(&trace_types_lock);
 }
 static void __tracing_reset(struct trace_array *tr, int cpu)
 {
 	ftrace_disable_cpu();
 	ring_buffer_reset_cpu(tr->buffer, cpu);
 	ftrace_enable_cpu();
 }
 void tracing_reset(struct trace_array *tr, int cpu)
 {
 	struct ring_buffer *buffer = tr->buffer;
 	ring_buffer_record_disable(buffer);
 	/* Make sure all commits have finished */
 	synchronize_sched();
 	__tracing_reset(tr, cpu);
 	ring_buffer_record_enable(buffer);
 }
 void tracing_reset_online_cpus(struct trace_array *tr)
 {
 	struct ring_buffer *buffer = tr->buffer;
 	int cpu;
 	ring_buffer_record_disable(buffer);
 	/* Make sure all commits have finished */
 	synchronize_sched();
 	tr->time_start = ftrace_now(tr->cpu);
 	for_each_online_cpu(cpu)
 		__tracing_reset(tr, cpu);
 	ring_buffer_record_enable(buffer);
 }
 void tracing_reset_current(int cpu)
 {
 	tracing_reset(&global_trace, cpu);
 }
 void tracing_reset_current_online_cpus(void)
 {
 	tracing_reset_online_cpus(&global_trace);
 }
 #define SAVED_CMDLINES 128
 #define NO_CMDLINE_MAP UINT_MAX
 static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
 static int cmdline_idx;
 static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 /* temporary disable recording */
 static atomic_t trace_record_cmdline_disabled __read_mostly;
 static void trace_init_cmdlines(void)
 {
 	memset(&map_pid_to_cmdline, NO_CMDLINE_MAP, sizeof(map_pid_to_cmdline));
 	memset(&map_cmdline_to_pid, NO_CMDLINE_MAP, sizeof(map_cmdline_to_pid));
 	cmdline_idx = 0;
 }
 int is_tracing_stopped(void)
 {
 	return trace_stop_count;
 }
 /**
  * ftrace_off_permanent - disable all ftrace code permanently
  *
  * This should only be called when a serious anomally has
  * been detected.  This will turn off the function tracing,
  * ring buffers, and other tracing utilites. It takes no
  * locks and can be called from any context.
  */
 void ftrace_off_permanent(void)
 {
 	tracing_disabled = 1;
 	ftrace_stop();
 	tracing_off_permanent();
 }
 /**
  * tracing_start - quick start of the tracer
  *
  * If tracing is enabled but was stopped by tracing_stop,
  * this will start the tracer back up.
  */
 void tracing_start(void)
 {
 	struct ring_buffer *buffer;
 	unsigned long flags;
 	if (tracing_disabled)
 		return;
 	spin_lock_irqsave(&tracing_start_lock, flags);
 	if (--trace_stop_count) {
 		if (trace_stop_count < 0) {
 			/* Someone screwed up their debugging */
 			WARN_ON_ONCE(1);
 			trace_stop_count = 0;
 		}
 		goto out;
 	}
 	buffer = global_trace.buffer;
 	if (buffer)
 		ring_buffer_record_enable(buffer);
 	buffer = max_tr.buffer;
 	if (buffer)
 		ring_buffer_record_enable(buffer);
 	ftrace_start();
  out:
 	spin_unlock_irqrestore(&tracing_start_lock, flags);
 }
 /**
  * tracing_stop - quick stop of the tracer
  *
  * Light weight way to stop tracing. Use in conjunction with
  * tracing_start.
  */
 void tracing_stop(void)
 {
 	struct ring_buffer *buffer;
 	unsigned long flags;
 	ftrace_stop();
 	spin_lock_irqsave(&tracing_start_lock, flags);
 	if (trace_stop_count++)
 		goto out;
 	buffer = global_trace.buffer;
 	if (buffer)
 		ring_buffer_record_disable(buffer);
 	buffer = max_tr.buffer;
 	if (buffer)
 		ring_buffer_record_disable(buffer);
  out:
 	spin_unlock_irqrestore(&tracing_start_lock, flags);
 }
 void trace_stop_cmdline_recording(void);
 static void trace_save_cmdline(struct task_struct *tsk)
 {
 	unsigned pid, idx;
 	if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
 		return;
 	/*
 	 * It's not the end of the world if we don't get
 	 * the lock, but we also don't want to spin
 	 * nor do we want to disable interrupts,
 	 * so if we miss here, then better luck next time.
 	 */
 	if (!arch_spin_trylock(&trace_cmdline_lock))
 		return;
 	idx = map_pid_to_cmdline[tsk->pid];
 	if (idx == NO_CMDLINE_MAP) {
 		idx = (cmdline_idx + 1) % SAVED_CMDLINES;
 		/*
 		 * Check whether the cmdline buffer at idx has a pid
 		 * mapped. We are going to overwrite that entry so we
 		 * need to clear the map_pid_to_cmdline. Otherwise we
 		 * would read the new comm for the old pid.
 		 */
 		pid = map_cmdline_to_pid[idx];
 		if (pid != NO_CMDLINE_MAP)
 			map_pid_to_cmdline[pid] = NO_CMDLINE_MAP;
 		map_cmdline_to_pid[idx] = tsk->pid;
 		map_pid_to_cmdline[tsk->pid] = idx;
 		cmdline_idx = idx;
 	}
 	memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
 	arch_spin_unlock(&trace_cmdline_lock);
 }
 void trace_find_cmdline(int pid, char comm[])
 {
 	unsigned map;
 	if (!pid) {
 		strcpy(comm, "<idle>");
 		return;
 	}
 	if (WARN_ON_ONCE(pid < 0)) {
 		strcpy(comm, "<XXX>");
 		return;
 	}
 	if (pid > PID_MAX_DEFAULT) {
 		strcpy(comm, "<...>");
 		return;
 	}
 	preempt_disable();
 	arch_spin_lock(&trace_cmdline_lock);
 	map = map_pid_to_cmdline[pid];
 	if (map != NO_CMDLINE_MAP)
 		strcpy(comm, saved_cmdlines[map]);
 	else
 		strcpy(comm, "<...>");
 	arch_spin_unlock(&trace_cmdline_lock);
 	preempt_enable();
 }
 void tracing_record_cmdline(struct task_struct *tsk)
 {
 	if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
 	    !tracing_is_on())
 		return;
 	trace_save_cmdline(tsk);
 }
 void
 tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 			     int pc)
 {
 	struct task_struct *tsk = current;
 	entry->preempt_count		= pc & 0xff;
 	entry->pid			= (tsk) ? tsk->pid : 0;
 	entry->lock_depth		= (tsk) ? tsk->lock_depth : 0;
 	entry->flags =
 #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
 		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
 #else
 		TRACE_FLAG_IRQS_NOSUPPORT |
 #endif
 		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
 		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
 		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
 }
 EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
 struct ring_buffer_event *
 trace_buffer_lock_reserve(struct ring_buffer *buffer,
 			  int type,
 			  unsigned long len,
 			  unsigned long flags, int pc)
 {
 	struct ring_buffer_event *event;
 	event = ring_buffer_lock_reserve(buffer, len);
 	if (event != NULL) {
 		struct trace_entry *ent = ring_buffer_event_data(event);
 		tracing_generic_entry_update(ent, flags, pc);
 		ent->type = type;
 	}
 	return event;
 }
 static inline void
 __trace_buffer_unlock_commit(struct ring_buffer *buffer,
 			     struct ring_buffer_event *event,
 			     unsigned long flags, int pc,
 			     int wake)
 {
 	ring_buffer_unlock_commit(buffer, event);
 	ftrace_trace_stack(buffer, flags, 6, pc);
 	ftrace_trace_userstack(buffer, flags, pc);
 	if (wake)
 		trace_wake_up();
 }
 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
 				struct ring_buffer_event *event,
 				unsigned long flags, int pc)
 {
 	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 }
 struct ring_buffer_event *
 trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
 				  int type, unsigned long len,
 				  unsigned long flags, int pc)
 {
 	*current_rb = global_trace.buffer;
 	return trace_buffer_lock_reserve(*current_rb,
 					 type, len, flags, pc);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
 void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
 					struct ring_buffer_event *event,
 					unsigned long flags, int pc)
 {
 	__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
 void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
 				       struct ring_buffer_event *event,
 				       unsigned long flags, int pc)
 {
 	__trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
 }
 EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
 void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
 					 struct ring_buffer_event *event)
 {
 	ring_buffer_discard_commit(buffer, event);
 }
 EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
 void
 trace_function(struct trace_array *tr,
 	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
 	       int pc)
 {
 	struct ftrace_event_call *call = &event_function;
 	struct ring_buffer *buffer = tr->buffer;
 	struct ring_buffer_event *event;
 	struct ftrace_entry *entry;
 	/* If we are reading the ring buffer, don't trace */
 	if (unlikely(__this_cpu_read(per_cpu_var(ftrace_cpu_disabled))))
 		return;
 	event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
 					  flags, pc);
 	if (!event)
 		return;
 	entry	= ring_buffer_event_data(event);
 	entry->ip			= ip;
 	entry->parent_ip		= parent_ip;
 	if (!filter_check_discard(call, entry, buffer, event))
 		ring_buffer_unlock_commit(buffer, event);
 }
 void
 ftrace(struct trace_array *tr, struct trace_array_cpu *data,
        unsigned long ip, unsigned long parent_ip, unsigned long flags,
        int pc)
 {
 	if (likely(!atomic_read(&data->disabled)))
 		trace_function(tr, ip, parent_ip, flags, pc);
 }
 #ifdef CONFIG_STACKTRACE
 static void __ftrace_trace_stack(struct ring_buffer *buffer,
 				 unsigned long flags,
 				 int skip, int pc)
 {
 	struct ftrace_event_call *call = &event_kernel_stack;
 	struct ring_buffer_event *event;
 	struct stack_entry *entry;
 	struct stack_trace trace;
 	event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
 					  sizeof(*entry), flags, pc);
 	if (!event)
 		return;
 	entry	= ring_buffer_event_data(event);
 	memset(&entry->caller, 0, sizeof(entry->caller));
 	trace.nr_entries	= 0;
 	trace.max_entries	= FTRACE_STACK_ENTRIES;
 	trace.skip		= skip;
 	trace.entries		= entry->caller;
 	save_stack_trace(&trace);
 	if (!filter_check_discard(call, entry, buffer, event))
 		ring_buffer_unlock_commit(buffer, event);
 }
 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
 			int skip, int pc)
 {
 	if (!(trace_flags & TRACE_ITER_STACKTRACE))
 		return;
 	__ftrace_trace_stack(buffer, flags, skip, pc);
 }
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
 		   int pc)
 {
 	__ftrace_trace_stack(tr->buffer, flags, skip, pc);
 }
 /**
  * trace_dump_stack - record a stack back trace in the trace buffer
  */
 void trace_dump_stack(void)
 {
 	unsigned long flags;
 	if (tracing_disabled || tracing_selftest_running)
 		return;
 	local_save_flags(flags);
 	/* skipping 3 traces, seems to get us at the caller of this function */
 	__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
 }
 void
 ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
 {
 	struct ftrace_event_call *call = &event_user_stack;
 	struct ring_buffer_event *event;
 	struct userstack_entry *entry;
 	struct stack_trace trace;
 	if (!(trace_flags & TRACE_ITER_USERSTACKTRACE))
 		return;
 	event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
 					  sizeof(*entry), flags, pc);
 	if (!event)
 		return;
 	entry	= ring_buffer_event_data(event);
 	entry->tgid		= current->tgid;
 	memset(&entry->caller, 0, sizeof(entry->caller));
 	trace.nr_entries	= 0;
 	trace.max_entries	= FTRACE_STACK_ENTRIES;
 	trace.skip		= 0;
 	trace.entries		= entry->caller;
 	save_stack_trace_user(&trace);
 	if (!filter_check_discard(call, entry, buffer, event))
 		ring_buffer_unlock_commit(buffer, event);
 }
 #ifdef UNUSED
 static void __trace_userstack(struct trace_array *tr, unsigned long flags)
 {
 	ftrace_trace_userstack(tr, flags, preempt_count());
 }
 #endif /* UNUSED */
 #endif /* CONFIG_STACKTRACE */
 static void
 ftrace_trace_special(void *__tr,
 		     unsigned long arg1, unsigned long arg2, unsigned long arg3,
 		     int pc)
 {
 	struct ftrace_event_call *call = &event_special;
 	struct ring_buffer_event *event;
 	struct trace_array *tr = __tr;
 	struct ring_buffer *buffer = tr->buffer;
 	struct special_entry *entry;
 	event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL,
 					  sizeof(*entry), 0, pc);
 	if (!event)
 		return;
 	entry	= ring_buffer_event_data(event);
 	entry->arg1			= arg1;
 	entry->arg2			= arg2;
 	entry->arg3			= arg3;
 	if (!filter_check_discard(call, entry, buffer, event))
 		trace_buffer_unlock_commit(buffer, event, 0, pc);
 }
 void
 __trace_special(void *__tr, void *__data,
 		unsigned long arg1, unsigned long arg2, unsigned long arg3)
 {
 	ftrace_trace_special(__tr, arg1, arg2, arg3, preempt_count());
 }
 void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
 {
 	struct trace_array *tr = &global_trace;
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	int cpu;
 	int pc;
 	if (tracing_disabled)
 		return;
 	pc = preempt_count();
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 	if (likely(atomic_inc_return(&data->disabled) == 1))
 		ftrace_trace_special(tr, arg1, arg2, arg3, pc);
 	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 }
 /**
  * trace_vbprintk - write binary msg to tracing buffer
  *
  */
 int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
 {
 	static arch_spinlock_t trace_buf_lock =
 		(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 	static u32 trace_buf[TRACE_BUF_SIZE];
 	struct ftrace_event_call *call = &event_bprint;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
 	struct trace_array *tr = &global_trace;
 	struct trace_array_cpu *data;
 	struct bprint_entry *entry;
 	unsigned long flags;
 	int disable;
 	int resched;
 	int cpu, len = 0, size, pc;
 	if (unlikely(tracing_selftest_running || tracing_disabled))
 		return 0;
 	/* Don't pollute graph traces with trace_vprintk internals */
 	pause_graph_tracing();
 	pc = preempt_count();
 	resched = ftrace_preempt_disable();
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 	disable = atomic_inc_return(&data->disabled);
 	if (unlikely(disable != 1))
 		goto out;
 	/* Lockdep uses trace_printk for lock tracing */
 	local_irq_save(flags);
 	arch_spin_lock(&trace_buf_lock);
 	len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
 	if (len > TRACE_BUF_SIZE || len < 0)
 		goto out_unlock;
 	size = sizeof(*entry) + sizeof(u32) * len;
 	buffer = tr->buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
 					  flags, pc);
 	if (!event)
 		goto out_unlock;
 	entry = ring_buffer_event_data(event);
 	entry->ip			= ip;
 	entry->fmt			= fmt;
 	memcpy(entry->buf, trace_buf, sizeof(u32) * len);
 	if (!filter_check_discard(call, entry, buffer, event)) {
 		ring_buffer_unlock_commit(buffer, event);
 		ftrace_trace_stack(buffer, flags, 6, pc);
 	}
 out_unlock:
 	arch_spin_unlock(&trace_buf_lock);
 	local_irq_restore(flags);
 out:
 	atomic_dec_return(&data->disabled);
 	ftrace_preempt_enable(resched);
 	unpause_graph_tracing();
 	return len;
 }
 EXPORT_SYMBOL_GPL(trace_vbprintk);
 int trace_array_printk(struct trace_array *tr,
 		       unsigned long ip, const char *fmt, ...)
 {
 	int ret;
 	va_list ap;
 	if (!(trace_flags & TRACE_ITER_PRINTK))
 		return 0;
 	va_start(ap, fmt);
 	ret = trace_array_vprintk(tr, ip, fmt, ap);
 	va_end(ap);
 	return ret;
 }
 int trace_array_vprintk(struct trace_array *tr,
 			unsigned long ip, const char *fmt, va_list args)
 {
 	static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 	static char trace_buf[TRACE_BUF_SIZE];
 	struct ftrace_event_call *call = &event_print;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
 	struct trace_array_cpu *data;
 	int cpu, len = 0, size, pc;
 	struct print_entry *entry;
 	unsigned long irq_flags;
 	int disable;
 	if (tracing_disabled || tracing_selftest_running)
 		return 0;
 	pc = preempt_count();
 	preempt_disable_notrace();
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 	disable = atomic_inc_return(&data->disabled);
 	if (unlikely(disable != 1))
 		goto out;
 	pause_graph_tracing();
 	raw_local_irq_save(irq_flags);
 	arch_spin_lock(&trace_buf_lock);
 	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
 	size = sizeof(*entry) + len + 1;
 	buffer = tr->buffer;
 	event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
 					  irq_flags, pc);
 	if (!event)
 		goto out_unlock;
 	entry = ring_buffer_event_data(event);
 	entry->ip = ip;
 	memcpy(&entry->buf, trace_buf, len);
 	entry->buf[len] = '\0';
 	if (!filter_check_discard(call, entry, buffer, event)) {
 		ring_buffer_unlock_commit(buffer, event);
 		ftrace_trace_stack(buffer, irq_flags, 6, pc);
 	}
  out_unlock:
 	arch_spin_unlock(&trace_buf_lock);
 	raw_local_irq_restore(irq_flags);
 	unpause_graph_tracing();
  out:
 	atomic_dec_return(&data->disabled);
 	preempt_enable_notrace();
 	return len;
 }
 int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
 {
 	return trace_array_vprintk(&global_trace, ip, fmt, args);
 }
 EXPORT_SYMBOL_GPL(trace_vprintk);
 enum trace_file_type {
 	TRACE_FILE_LAT_FMT	= 1,
 	TRACE_FILE_ANNOTATE	= 2,
 };
 static void trace_iterator_increment(struct trace_iterator *iter)
 {
 	/* Don't allow ftrace to trace into the ring buffers */
 	ftrace_disable_cpu();
 	iter->idx++;
 	if (iter->buffer_iter[iter->cpu])
 		ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
 	ftrace_enable_cpu();
 }
 static struct trace_entry *
 peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts)
 {
 	struct ring_buffer_event *event;
 	struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
 	/* Don't allow ftrace to trace into the ring buffers */
 	ftrace_disable_cpu();
 	if (buf_iter)
 		event = ring_buffer_iter_peek(buf_iter, ts);
 	else
 		event = ring_buffer_peek(iter->tr->buffer, cpu, ts);
 	ftrace_enable_cpu();
 	return event ? ring_buffer_event_data(event) : NULL;
 }
 static struct trace_entry *
 __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts)
 {
 	struct ring_buffer *buffer = iter->tr->buffer;
 	struct trace_entry *ent, *next = NULL;
 	int cpu_file = iter->cpu_file;
 	u64 next_ts = 0, ts;
 	int next_cpu = -1;
 	int cpu;
 	/*
 	 * If we are in a per_cpu trace file, don't bother by iterating over
 	 * all cpu and peek directly.
 	 */
 	if (cpu_file > TRACE_PIPE_ALL_CPU) {
 		if (ring_buffer_empty_cpu(buffer, cpu_file))
 			return NULL;
 		ent = peek_next_entry(iter, cpu_file, ent_ts);
 		if (ent_cpu)
 			*ent_cpu = cpu_file;
 		return ent;
 	}
 	for_each_tracing_cpu(cpu) {
 		if (ring_buffer_empty_cpu(buffer, cpu))
 			continue;
 		ent = peek_next_entry(iter, cpu, &ts);
 		/*
 		 * Pick the entry with the smallest timestamp:
 		 */
 		if (ent && (!next || ts < next_ts)) {
 			next = ent;
 			next_cpu = cpu;
 			next_ts = ts;
 		}
 	}
 	if (ent_cpu)
 		*ent_cpu = next_cpu;
 	if (ent_ts)
 		*ent_ts = next_ts;
 	return next;
 }
 /* Find the next real entry, without updating the iterator itself */
 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 					  int *ent_cpu, u64 *ent_ts)
 {
 	return __find_next_entry(iter, ent_cpu, ent_ts);
 }
 /* Find the next real entry, and increment the iterator to the next entry */
 static void *find_next_entry_inc(struct trace_iterator *iter)
 {
 	iter->ent = __find_next_entry(iter, &iter->cpu, &iter->ts);
 	if (iter->ent)
 		trace_iterator_increment(iter);
 	return iter->ent ? iter : NULL;
 }
 static void trace_consume(struct trace_iterator *iter)
 {
 	/* Don't allow ftrace to trace into the ring buffers */
 	ftrace_disable_cpu();
 	ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts);
 	ftrace_enable_cpu();
 }
 static void *s_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	struct trace_iterator *iter = m->private;
 	int i = (int)*pos;
 	void *ent;
 	WARN_ON_ONCE(iter->leftover);
 	(*pos)++;
 	/* can't go backwards */
 	if (iter->idx > i)
 		return NULL;
 	if (iter->idx < 0)
 		ent = find_next_entry_inc(iter);
 	else
 		ent = iter;
 	while (ent && iter->idx < i)
 		ent = find_next_entry_inc(iter);
 	iter->pos = *pos;
 	return ent;
 }
 static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
 {
 	struct trace_array *tr = iter->tr;
 	struct ring_buffer_event *event;
 	struct ring_buffer_iter *buf_iter;
 	unsigned long entries = 0;
 	u64 ts;
 	tr->data[cpu]->skipped_entries = 0;
 	if (!iter->buffer_iter[cpu])
 		return;
 	buf_iter = iter->buffer_iter[cpu];
 	ring_buffer_iter_reset(buf_iter);
 	/*
 	 * We could have the case with the max latency tracers
 	 * that a reset never took place on a cpu. This is evident
 	 * by the timestamp being before the start of the buffer.
 	 */
 	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
 		if (ts >= iter->tr->time_start)
 			break;
 		entries++;
 		ring_buffer_read(buf_iter, NULL);
 	}
 	tr->data[cpu]->skipped_entries = entries;
 }
 /*
  * The current tracer is copied to avoid a global locking
  * all around.
  */
 static void *s_start(struct seq_file *m, loff_t *pos)
 {
 	struct trace_iterator *iter = m->private;
 	static struct tracer *old_tracer;
 	int cpu_file = iter->cpu_file;
 	void *p = NULL;
 	loff_t l = 0;
 	int cpu;
 	/* copy the tracer to avoid using a global lock all around */
 	mutex_lock(&trace_types_lock);
 	if (unlikely(old_tracer != current_trace && current_trace)) {
 		old_tracer = current_trace;
 		*iter->trace = *current_trace;
 	}
 	mutex_unlock(&trace_types_lock);
 	atomic_inc(&trace_record_cmdline_disabled);
 	if (*pos != iter->pos) {
 		iter->ent = NULL;
 		iter->cpu = 0;
 		iter->idx = -1;
 		ftrace_disable_cpu();
 		if (cpu_file == TRACE_PIPE_ALL_CPU) {
 			for_each_tracing_cpu(cpu)
 				tracing_iter_reset(iter, cpu);
 		} else
 			tracing_iter_reset(iter, cpu_file);
 		ftrace_enable_cpu();
 		iter->leftover = 0;
 		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
 			;
 	} else {
 		/*
 		 * If we overflowed the seq_file before, then we want
 		 * to just reuse the trace_seq buffer again.
 		 */
 		if (iter->leftover)
 			p = iter;
 		else {
 			l = *pos - 1;
 			p = s_next(m, p, &l);
 		}
 	}
 	trace_event_read_lock();
 	trace_access_lock(cpu_file);
 	return p;
 }
 static void s_stop(struct seq_file *m, void *p)
 {
 	struct trace_iterator *iter = m->private;
 	atomic_dec(&trace_record_cmdline_disabled);
 	trace_access_unlock(iter->cpu_file);
 	trace_event_read_unlock();
 }
 static void print_lat_help_header(struct seq_file *m)
 {
 	seq_puts(m, "#                  _------=> CPU#            \n");
 	seq_puts(m, "#                 / _-----=> irqs-off        \n");
 	seq_puts(m, "#                | / _----=> need-resched    \n");
 	seq_puts(m, "#                || / _---=> hardirq/softirq \n");
 	seq_puts(m, "#                ||| / _--=> preempt-depth   \n");
 	seq_puts(m, "#                |||| /_--=> lock-depth       \n");
 	seq_puts(m, "#                |||||/     delay             \n");
 	seq_puts(m, "#  cmd     pid   |||||| time  |   caller      \n");
 	seq_puts(m, "#     \\   /      ||||||   \\   |   /           \n");
 }
 static void print_func_help_header(struct seq_file *m)
 {
 	seq_puts(m, "#           TASK-PID    CPU#    TIMESTAMP  FUNCTION\n");
 	seq_puts(m, "#              | |       |          |         |\n");
 }
 static void
 print_trace_header(struct seq_file *m, struct trace_iterator *iter)
 {
 	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 	struct trace_array *tr = iter->tr;
 	struct trace_array_cpu *data = tr->data[tr->cpu];
 	struct tracer *type = current_trace;
 	unsigned long entries = 0;
 	unsigned long total = 0;
 	unsigned long count;
 	const char *name = "preemption";
 	int cpu;
 	if (type)
 		name = type->name;
 	for_each_tracing_cpu(cpu) {
 		count = ring_buffer_entries_cpu(tr->buffer, cpu);
 		/*
 		 * If this buffer has skipped entries, then we hold all
 		 * entries for the trace and we need to ignore the
 		 * ones before the time stamp.
 		 */
 		if (tr->data[cpu]->skipped_entries) {
 			count -= tr->data[cpu]->skipped_entries;
 			/* total is the same as the entries */
 			total += count;
 		} else
 			total += count +
 				ring_buffer_overrun_cpu(tr->buffer, cpu);
 		entries += count;
 	}
 	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
 		   name, UTS_RELEASE);
 	seq_puts(m, "# -----------------------------------"
 		 "---------------------------------\n");
 	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
 		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
 		   nsecs_to_usecs(data->saved_latency),
 		   entries,
 		   total,
 		   tr->cpu,
 #if defined(CONFIG_PREEMPT_NONE)
 		   "server",
 #elif defined(CONFIG_PREEMPT_VOLUNTARY)
 		   "desktop",
 #elif defined(CONFIG_PREEMPT)
 		   "preempt",
 #else
 		   "unknown",
 #endif
 		   /* These are reserved for later use */
 		   0, 0, 0, 0);
 #ifdef CONFIG_SMP
 	seq_printf(m, " #P:%d)\n", num_online_cpus());
 #else
 	seq_puts(m, ")\n");
 #endif
 	seq_puts(m, "#    -----------------\n");
 	seq_printf(m, "#    | task: %.16s-%d "
 		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
 		   data->comm, data->pid, data->uid, data->nice,
 		   data->policy, data->rt_priority);
 	seq_puts(m, "#    -----------------\n");
 	if (data->critical_start) {
 		seq_puts(m, "#  => started at: ");
 		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
 		trace_print_seq(m, &iter->seq);
 		seq_puts(m, "\n#  => ended at:   ");
 		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
 		trace_print_seq(m, &iter->seq);
 		seq_puts(m, "\n#\n");
 	}
 	seq_puts(m, "#\n");
 }
 static void test_cpu_buff_start(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	if (!(trace_flags & TRACE_ITER_ANNOTATE))
 		return;
 	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
 		return;
 	if (cpumask_test_cpu(iter->cpu, iter->started))
 		return;
 	if (iter->tr->data[iter->cpu]->skipped_entries)
 		return;
 	cpumask_set_cpu(iter->cpu, iter->started);
 	/* Don't print started cpu buffer for the first entry of the trace */
 	if (iter->idx > 1)
 		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
 				iter->cpu);
 }
 static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 	struct trace_entry *entry;
 	struct trace_event *event;
 	entry = iter->ent;
 	test_cpu_buff_start(iter);
 	event = ftrace_find_event(entry->type);
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
 			if (!trace_print_lat_context(iter))
 				goto partial;
 		} else {
 			if (!trace_print_context(iter))
 				goto partial;
 		}
 	}
 	if (event)
 		return event->trace(iter, sym_flags);
 	if (!trace_seq_printf(s, "Unknown type %d\n", entry->type))
 		goto partial;
 	return TRACE_TYPE_HANDLED;
 partial:
 	return TRACE_TYPE_PARTIAL_LINE;
 }
 static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry;
 	struct trace_event *event;
 	entry = iter->ent;
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		if (!trace_seq_printf(s, "%d %d %llu ",
 				      entry->pid, iter->cpu, iter->ts))
 			goto partial;
 	}
 	event = ftrace_find_event(entry->type);
 	if (event)
 		return event->raw(iter, 0);
 	if (!trace_seq_printf(s, "%d ?\n", entry->type))
 		goto partial;
 	return TRACE_TYPE_HANDLED;
 partial:
 	return TRACE_TYPE_PARTIAL_LINE;
 }
 static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	unsigned char newline = '\n';
 	struct trace_entry *entry;
 	struct trace_event *event;
 	entry = iter->ent;
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
 		SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
 		SEQ_PUT_HEX_FIELD_RET(s, iter->ts);
 	}
 	event = ftrace_find_event(entry->type);
 	if (event) {
 		enum print_line_t ret = event->hex(iter, 0);
 		if (ret != TRACE_TYPE_HANDLED)
 			return ret;
 	}
 	SEQ_PUT_FIELD_RET(s, newline);
 	return TRACE_TYPE_HANDLED;
 }
 static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
 {
 	struct trace_seq *s = &iter->seq;
 	struct trace_entry *entry;
 	struct trace_event *event;
 	entry = iter->ent;
 	if (trace_flags & TRACE_ITER_CONTEXT_INFO) {
 		SEQ_PUT_FIELD_RET(s, entry->pid);
 		SEQ_PUT_FIELD_RET(s, iter->cpu);
 		SEQ_PUT_FIELD_RET(s, iter->ts);
 	}
 	event = ftrace_find_event(entry->type);
 	return event ? event->binary(iter, 0) : TRACE_TYPE_HANDLED;
 }
 static int trace_empty(struct trace_iterator *iter)
 {
 	int cpu;
 	/* If we are looking at one CPU buffer, only check that one */
 	if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
 		cpu = iter->cpu_file;
 		if (iter->buffer_iter[cpu]) {
 			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
 				return 0;
 		} else {
 			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
 				return 0;
 		}
 		return 1;
 	}
 	for_each_tracing_cpu(cpu) {
 		if (iter->buffer_iter[cpu]) {
 			if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
 				return 0;
 		} else {
 			if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
 				return 0;
 		}
 	}
 	return 1;
 }
 /*  Called with trace_event_read_lock() held. */
 static enum print_line_t print_trace_line(struct trace_iterator *iter)
 {
 	enum print_line_t ret;
 	if (iter->trace && iter->trace->print_line) {
 		ret = iter->trace->print_line(iter);
 		if (ret != TRACE_TYPE_UNHANDLED)
 			return ret;
 	}
 	if (iter->ent->type == TRACE_BPRINT &&
 			trace_flags & TRACE_ITER_PRINTK &&
 			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
 		return trace_print_bprintk_msg_only(iter);
 	if (iter->ent->type == TRACE_PRINT &&
 			trace_flags & TRACE_ITER_PRINTK &&
 			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
 		return trace_print_printk_msg_only(iter);
 	if (trace_flags & TRACE_ITER_BIN)
 		return print_bin_fmt(iter);
 	if (trace_flags & TRACE_ITER_HEX)
 		return print_hex_fmt(iter);
 	if (trace_flags & TRACE_ITER_RAW)
 		return print_raw_fmt(iter);
 	return print_trace_fmt(iter);
 }
 static int s_show(struct seq_file *m, void *v)
 {
 	struct trace_iterator *iter = v;
 	int ret;
 	if (iter->ent == NULL) {
 		if (iter->tr) {
 			seq_printf(m, "# tracer: %s\n", iter->trace->name);
 			seq_puts(m, "#\n");
 		}
 		if (iter->trace && iter->trace->print_header)
 			iter->trace->print_header(m);
 		else if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
 			/* print nothing if the buffers are empty */
 			if (trace_empty(iter))
 				return 0;
 			print_trace_header(m, iter);
 			if (!(trace_flags & TRACE_ITER_VERBOSE))
 				print_lat_help_header(m);
 		} else {
 			if (!(trace_flags & TRACE_ITER_VERBOSE))
 				print_func_help_header(m);
 		}
 	} else if (iter->leftover) {
 		/*
 		 * If we filled the seq_file buffer earlier, we
 		 * want to just show it now.
 		 */
 		ret = trace_print_seq(m, &iter->seq);
 		/* ret should this time be zero, but you never know */
 		iter->leftover = ret;
 	} else {
 		print_trace_line(iter);
 		ret = trace_print_seq(m, &iter->seq);
 		/*
 		 * If we overflow the seq_file buffer, then it will
 		 * ask us for this data again at start up.
 		 * Use that instead.
 		 *  ret is 0 if seq_file write succeeded.
 		 *        -1 otherwise.
 		 */
 		iter->leftover = ret;
 	}
 	return 0;
 }
 static const struct seq_operations tracer_seq_ops = {
 	.start		= s_start,
 	.next		= s_next,
 	.stop		= s_stop,
 	.show		= s_show,
 };
 static struct trace_iterator *
 __tracing_open(struct inode *inode, struct file *file)
 {
 	long cpu_file = (long) inode->i_private;
 	void *fail_ret = ERR_PTR(-ENOMEM);
 	struct trace_iterator *iter;
 	struct seq_file *m;
 	int cpu, ret;
 	if (tracing_disabled)
 		return ERR_PTR(-ENODEV);
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (!iter)
 		return ERR_PTR(-ENOMEM);
 	/*
 	 * We make a copy of the current tracer to avoid concurrent
 	 * changes on it while we are reading.
 	 */
 	mutex_lock(&trace_types_lock);
 	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
 	if (!iter->trace)
 		goto fail;
 	if (current_trace)
 		*iter->trace = *current_trace;
 	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
 		goto fail;
 	if (current_trace && current_trace->print_max)
 		iter->tr = &max_tr;
 	else
 		iter->tr = &global_trace;
 	iter->pos = -1;
 	mutex_init(&iter->mutex);
 	iter->cpu_file = cpu_file;
 	/* Notify the tracer early; before we stop tracing. */
 	if (iter->trace && iter->trace->open)
 		iter->trace->open(iter);
 	/* Annotate start of buffers if we had overruns */
 	if (ring_buffer_overruns(iter->tr->buffer))
 		iter->iter_flags |= TRACE_FILE_ANNOTATE;
 	/* stop the trace while dumping */
 	tracing_stop();
 	if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
 		for_each_tracing_cpu(cpu) {
 			iter->buffer_iter[cpu] =
 				ring_buffer_read_start(iter->tr->buffer, cpu);
 			tracing_iter_reset(iter, cpu);
 		}
 	} else {
 		cpu = iter->cpu_file;
 		iter->buffer_iter[cpu] =
 				ring_buffer_read_start(iter->tr->buffer, cpu);
 		tracing_iter_reset(iter, cpu);
 	}
 	ret = seq_open(file, &tracer_seq_ops);
 	if (ret < 0) {
 		fail_ret = ERR_PTR(ret);
 		goto fail_buffer;
 	}
 	m = file->private_data;
 	m->private = iter;
 	mutex_unlock(&trace_types_lock);
 	return iter;
  fail_buffer:
 	for_each_tracing_cpu(cpu) {
 		if (iter->buffer_iter[cpu])
 			ring_buffer_read_finish(iter->buffer_iter[cpu]);
 	}
 	free_cpumask_var(iter->started);
 	tracing_start();
  fail:
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
 	kfree(iter);
 	return fail_ret;
 }
 int tracing_open_generic(struct inode *inode, struct file *filp)
 {
 	if (tracing_disabled)
 		return -ENODEV;
 	filp->private_data = inode->i_private;
 	return 0;
 }
 static int tracing_release(struct inode *inode, struct file *file)
 {
 	struct seq_file *m = (struct seq_file *)file->private_data;
 	struct trace_iterator *iter;
 	int cpu;
 	if (!(file->f_mode & FMODE_READ))
 		return 0;
 	iter = m->private;
 	mutex_lock(&trace_types_lock);
 	for_each_tracing_cpu(cpu) {
 		if (iter->buffer_iter[cpu])
 			ring_buffer_read_finish(iter->buffer_iter[cpu]);
 	}
 	if (iter->trace && iter->trace->close)
 		iter->trace->close(iter);
 	/* reenable tracing if it was previously enabled */
 	tracing_start();
 	mutex_unlock(&trace_types_lock);
 	seq_release(inode, file);
 	mutex_destroy(&iter->mutex);
 	free_cpumask_var(iter->started);
 	kfree(iter->trace);
 	kfree(iter);
 	return 0;
 }
 static int tracing_open(struct inode *inode, struct file *file)
 {
 	struct trace_iterator *iter;
 	int ret = 0;
 	/* If this file was open for write, then erase contents */
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC)) {
 		long cpu = (long) inode->i_private;
 		if (cpu == TRACE_PIPE_ALL_CPU)
 			tracing_reset_online_cpus(&global_trace);
 		else
 			tracing_reset(&global_trace, cpu);
 	}
 	if (file->f_mode & FMODE_READ) {
 		iter = __tracing_open(inode, file);
 		if (IS_ERR(iter))
 			ret = PTR_ERR(iter);
 		else if (trace_flags & TRACE_ITER_LATENCY_FMT)
 			iter->iter_flags |= TRACE_FILE_LAT_FMT;
 	}
 	return ret;
 }
 static void *
 t_next(struct seq_file *m, void *v, loff_t *pos)
 {
 	struct tracer *t = v;
 	(*pos)++;
 	if (t)
 		t = t->next;
 	return t;
 }
 static void *t_start(struct seq_file *m, loff_t *pos)
 {
 	struct tracer *t;
 	loff_t l = 0;
 	mutex_lock(&trace_types_lock);
 	for (t = trace_types; t && l < *pos; t = t_next(m, t, &l))
 		;
 	return t;
 }
 static void t_stop(struct seq_file *m, void *p)
 {
 	mutex_unlock(&trace_types_lock);
 }
 static int t_show(struct seq_file *m, void *v)
 {
 	struct tracer *t = v;
 	if (!t)
 		return 0;
 	seq_printf(m, "%s", t->name);
 	if (t->next)
 		seq_putc(m, ' ');
 	else
 		seq_putc(m, '\n');
 	return 0;
 }
 static const struct seq_operations show_traces_seq_ops = {
 	.start		= t_start,
 	.next		= t_next,
 	.stop		= t_stop,
 	.show		= t_show,
 };
 static int show_traces_open(struct inode *inode, struct file *file)
 {
 	if (tracing_disabled)
 		return -ENODEV;
 	return seq_open(file, &show_traces_seq_ops);
 }
 static ssize_t
 tracing_write_stub(struct file *filp, const char __user *ubuf,
 		   size_t count, loff_t *ppos)
 {
 	return count;
 }
 static const struct file_operations tracing_fops = {
 	.open		= tracing_open,
 	.read		= seq_read,
 	.write		= tracing_write_stub,
 	.llseek		= seq_lseek,
 	.release	= tracing_release,
 };
 static const struct file_operations show_traces_fops = {
 	.open		= show_traces_open,
 	.read		= seq_read,
 	.release	= seq_release,
 };
 /*
  * Only trace on a CPU if the bitmask is set:
  */
 static cpumask_var_t tracing_cpumask;
 /*
  * The tracer itself will not take this lock, but still we want
  * to provide a consistent cpumask to user-space:
  */
 static DEFINE_MUTEX(tracing_cpumask_update_lock);
 /*
  * Temporary storage for the character representation of the
  * CPU bitmask (and one more byte for the newline):
  */
 static char mask_str[NR_CPUS + 1];
 static ssize_t
 tracing_cpumask_read(struct file *filp, char __user *ubuf,
 		     size_t count, loff_t *ppos)
 {
 	int len;
 	mutex_lock(&tracing_cpumask_update_lock);
 	len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
 	if (count - len < 2) {
 		count = -EINVAL;
 		goto out_err;
 	}
 	len += sprintf(mask_str + len, "\n");
 	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
 out_err:
 	mutex_unlock(&tracing_cpumask_update_lock);
 	return count;
 }
 static ssize_t
 tracing_cpumask_write(struct file *filp, const char __user *ubuf,
 		      size_t count, loff_t *ppos)
 {
 	int err, cpu;
 	cpumask_var_t tracing_cpumask_new;
 	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
 		return -ENOMEM;
 	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
 	if (err)
 		goto err_unlock;
 	mutex_lock(&tracing_cpumask_update_lock);
 	local_irq_disable();
 	arch_spin_lock(&ftrace_max_lock);
 	for_each_tracing_cpu(cpu) {
 		/*
 		 * Increase/decrease the disabled counter if we are
 		 * about to flip a bit in the cpumask:
 		 */
 		if (cpumask_test_cpu(cpu, tracing_cpumask) &&
 				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
 			atomic_inc(&global_trace.data[cpu]->disabled);
 		}
 		if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
 				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
 			atomic_dec(&global_trace.data[cpu]->disabled);
 		}
 	}
 	arch_spin_unlock(&ftrace_max_lock);
 	local_irq_enable();
 	cpumask_copy(tracing_cpumask, tracing_cpumask_new);
 	mutex_unlock(&tracing_cpumask_update_lock);
 	free_cpumask_var(tracing_cpumask_new);
 	return count;
 err_unlock:
 	free_cpumask_var(tracing_cpumask_new);
 	return err;
 }
 static const struct file_operations tracing_cpumask_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_cpumask_read,
 	.write		= tracing_cpumask_write,
 };
 static int tracing_trace_options_show(struct seq_file *m, void *v)
 {
 	struct tracer_opt *trace_opts;
 	u32 tracer_flags;
 	int i;
 	mutex_lock(&trace_types_lock);
 	tracer_flags = current_trace->flags->val;
 	trace_opts = current_trace->flags->opts;
 	for (i = 0; trace_options[i]; i++) {
 		if (trace_flags & (1 << i))
 			seq_printf(m, "%s\n", trace_options[i]);
 		else
 			seq_printf(m, "no%s\n", trace_options[i]);
 	}
 	for (i = 0; trace_opts[i].name; i++) {
 		if (tracer_flags & trace_opts[i].bit)
 			seq_printf(m, "%s\n", trace_opts[i].name);
 		else
 			seq_printf(m, "no%s\n", trace_opts[i].name);
 	}
 	mutex_unlock(&trace_types_lock);
 	return 0;
 }
 static int __set_tracer_option(struct tracer *trace,
 			       struct tracer_flags *tracer_flags,
 			       struct tracer_opt *opts, int neg)
 {
 	int ret;
 	ret = trace->set_flag(tracer_flags->val, opts->bit, !neg);
 	if (ret)
 		return ret;
 	if (neg)
 		tracer_flags->val &= ~opts->bit;
 	else
 		tracer_flags->val |= opts->bit;
 	return 0;
 }
 /* Try to assign a tracer specific option */
 static int set_tracer_option(struct tracer *trace, char *cmp, int neg)
 {
 	struct tracer_flags *tracer_flags = trace->flags;
 	struct tracer_opt *opts = NULL;
 	int i;
 	for (i = 0; tracer_flags->opts[i].name; i++) {
 		opts = &tracer_flags->opts[i];
 		if (strcmp(cmp, opts->name) == 0)
 			return __set_tracer_option(trace, trace->flags,
 						   opts, neg);
 	}
 	return -EINVAL;
 }
 static void set_tracer_flags(unsigned int mask, int enabled)
 {
 	/* do nothing if flag is already set */
 	if (!!(trace_flags & mask) == !!enabled)
 		return;
 	if (enabled)
 		trace_flags |= mask;
 	else
 		trace_flags &= ~mask;
 }
 static ssize_t
 tracing_trace_options_write(struct file *filp, const char __user *ubuf,
 			size_t cnt, loff_t *ppos)
 {
 	char buf[64];
 	char *cmp;
 	int neg = 0;
 	int ret;
 	int i;
 	if (cnt >= sizeof(buf))
 		return -EINVAL;
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;
 	buf[cnt] = 0;
 	cmp = strstrip(buf);
 	if (strncmp(cmp, "no", 2) == 0) {
 		neg = 1;
 		cmp += 2;
 	}
 	for (i = 0; trace_options[i]; i++) {
 		if (strcmp(cmp, trace_options[i]) == 0) {
 			set_tracer_flags(1 << i, !neg);
 			break;
 		}
 	}
 	/* If no option could be set, test the specific tracer options */
 	if (!trace_options[i]) {
 		mutex_lock(&trace_types_lock);
 		ret = set_tracer_option(current_trace, cmp, neg);
 		mutex_unlock(&trace_types_lock);
 		if (ret)
 			return ret;
 	}
 	*ppos += cnt;
 	return cnt;
 }
 static int tracing_trace_options_open(struct inode *inode, struct file *file)
 {
 	if (tracing_disabled)
 		return -ENODEV;
 	return single_open(file, tracing_trace_options_show, NULL);
 }
 static const struct file_operations tracing_iter_fops = {
 	.open		= tracing_trace_options_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 	.write		= tracing_trace_options_write,
 };
 static const char readme_msg[] =
 	"tracing mini-HOWTO:\n\n"
 	"# mount -t debugfs nodev /sys/kernel/debug\n\n"
 	"# cat /sys/kernel/debug/tracing/available_tracers\n"
 	"wakeup preemptirqsoff preemptoff irqsoff function sched_switch nop\n\n"
 	"# cat /sys/kernel/debug/tracing/current_tracer\n"
 	"nop\n"
 	"# echo sched_switch > /sys/kernel/debug/tracing/current_tracer\n"
 	"# cat /sys/kernel/debug/tracing/current_tracer\n"
 	"sched_switch\n"
 	"# cat /sys/kernel/debug/tracing/trace_options\n"
 	"noprint-parent nosym-offset nosym-addr noverbose\n"
 	"# echo print-parent > /sys/kernel/debug/tracing/trace_options\n"
 	"# echo 1 > /sys/kernel/debug/tracing/tracing_enabled\n"
 	"# cat /sys/kernel/debug/tracing/trace > /tmp/trace.txt\n"
 	"# echo 0 > /sys/kernel/debug/tracing/tracing_enabled\n"
 ;
 static ssize_t
 tracing_readme_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
 {
 	return simple_read_from_buffer(ubuf, cnt, ppos,
 					readme_msg, strlen(readme_msg));
 }
 static const struct file_operations tracing_readme_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_readme_read,
 };
 static ssize_t
 tracing_saved_cmdlines_read(struct file *file, char __user *ubuf,
 				size_t cnt, loff_t *ppos)
 {
 	char *buf_comm;
 	char *file_buf;
 	char *buf;
 	int len = 0;
 	int pid;
 	int i;
 	file_buf = kmalloc(SAVED_CMDLINES*(16+TASK_COMM_LEN), GFP_KERNEL);
 	if (!file_buf)
 		return -ENOMEM;
 	buf_comm = kmalloc(TASK_COMM_LEN, GFP_KERNEL);
 	if (!buf_comm) {
 		kfree(file_buf);
 		return -ENOMEM;
 	}
 	buf = file_buf;
 	for (i = 0; i < SAVED_CMDLINES; i++) {
 		int r;
 		pid = map_cmdline_to_pid[i];
 		if (pid == -1 || pid == NO_CMDLINE_MAP)
 			continue;
 		trace_find_cmdline(pid, buf_comm);
 		r = sprintf(buf, "%d %s\n", pid, buf_comm);
 		buf += r;
 		len += r;
 	}
 	len = simple_read_from_buffer(ubuf, cnt, ppos,
 				      file_buf, len);
 	kfree(file_buf);
 	kfree(buf_comm);
 	return len;
 }
 static const struct file_operations tracing_saved_cmdlines_fops = {
     .open       = tracing_open_generic,
     .read       = tracing_saved_cmdlines_read,
 };
 static ssize_t
 tracing_ctrl_read(struct file *filp, char __user *ubuf,
 		  size_t cnt, loff_t *ppos)
 {
 	char buf[64];
 	int r;
 	r = sprintf(buf, "%u\n", tracer_enabled);
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 static ssize_t
 tracing_ctrl_write(struct file *filp, const char __user *ubuf,
 		   size_t cnt, loff_t *ppos)
 {
 	struct trace_array *tr = filp->private_data;
 	char buf[64];
 	unsigned long val;
 	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(&trace_types_lock);
 	if (tracer_enabled ^ val) {
 		if (val) {
 			tracer_enabled = 1;
 			if (current_trace->start)
 				current_trace->start(tr);
 			tracing_start();
 		} else {
 			tracer_enabled = 0;
 			tracing_stop();
 			if (current_trace->stop)
 				current_trace->stop(tr);
 		}
 	}
 	mutex_unlock(&trace_types_lock);
 	*ppos += cnt;
 	return cnt;
 }
 static ssize_t
 tracing_set_trace_read(struct file *filp, char __user *ubuf,
 		       size_t cnt, loff_t *ppos)
 {
 	char buf[MAX_TRACER_SIZE+2];
 	int r;
 	mutex_lock(&trace_types_lock);
 	if (current_trace)
 		r = sprintf(buf, "%s\n", current_trace->name);
 	else
 		r = sprintf(buf, "\n");
 	mutex_unlock(&trace_types_lock);
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 int tracer_init(struct tracer *t, struct trace_array *tr)
 {
 	tracing_reset_online_cpus(tr);
 	return t->init(tr);
 }
 static int tracing_resize_ring_buffer(unsigned long size)
 {
 	int ret;
 	/*
 	 * If kernel or user changes the size of the ring buffer
 	 * we use the size that was given, and we can forget about
 	 * expanding it later.
 	 */
 	ring_buffer_expanded = 1;
 	ret = ring_buffer_resize(global_trace.buffer, size);
 	if (ret < 0)
 		return ret;
 	ret = ring_buffer_resize(max_tr.buffer, size);
 	if (ret < 0) {
 		int r;
 		r = ring_buffer_resize(global_trace.buffer,
 				       global_trace.entries);
 		if (r < 0) {
 			/*
 			 * AARGH! We are left with different
 			 * size max buffer!!!!
 			 * The max buffer is our "snapshot" buffer.
 			 * When a tracer needs a snapshot (one of the
 			 * latency tracers), it swaps the max buffer
 			 * with the saved snap shot. We succeeded to
 			 * update the size of the main buffer, but failed to
 			 * update the size of the max buffer. But when we tried
 			 * to reset the main buffer to the original size, we
 			 * failed there too. This is very unlikely to
 			 * happen, but if it does, warn and kill all
 			 * tracing.
 			 */
 			WARN_ON(1);
 			tracing_disabled = 1;
 		}
 		return ret;
 	}
 	global_trace.entries = size;
 	return ret;
 }
 /**
  * tracing_update_buffers - used by tracing facility to expand ring buffers
  *
  * To save on memory when the tracing is never used on a system with it
  * configured in. The ring buffers are set to a minimum size. But once
  * a user starts to use the tracing facility, then they need to grow
  * to their default size.
  *
  * This function is to be called when a tracer is about to be used.
  */
 int tracing_update_buffers(void)
 {
 	int ret = 0;
 	mutex_lock(&trace_types_lock);
 	if (!ring_buffer_expanded)
 		ret = tracing_resize_ring_buffer(trace_buf_size);
 	mutex_unlock(&trace_types_lock);
 	return ret;
 }
 struct trace_option_dentry;
 static struct trace_option_dentry *
 create_trace_option_files(struct tracer *tracer);
 static void
 destroy_trace_option_files(struct trace_option_dentry *topts);
 static int tracing_set_tracer(const char *buf)
 {
 	static struct trace_option_dentry *topts;
 	struct trace_array *tr = &global_trace;
 	struct tracer *t;
 	int ret = 0;
 	mutex_lock(&trace_types_lock);
 	if (!ring_buffer_expanded) {
 		ret = tracing_resize_ring_buffer(trace_buf_size);
 		if (ret < 0)
 			goto out;
 		ret = 0;
 	}
 	for (t = trace_types; t; t = t->next) {
 		if (strcmp(t->name, buf) == 0)
 			break;
 	}
 	if (!t) {
 		ret = -EINVAL;
 		goto out;
 	}
 	if (t == current_trace)
 		goto out;
 	trace_branch_disable();
 	if (current_trace && current_trace->reset)
 		current_trace->reset(tr);
 	destroy_trace_option_files(topts);
 	current_trace = t;
 	topts = create_trace_option_files(current_trace);
 	if (t->init) {
 		ret = tracer_init(t, tr);
 		if (ret)
 			goto out;
 	}
 	trace_branch_enable(tr);
  out:
 	mutex_unlock(&trace_types_lock);
 	return ret;
 }
 static ssize_t
 tracing_set_trace_write(struct file *filp, const char __user *ubuf,
 			size_t cnt, loff_t *ppos)
 {
 	char buf[MAX_TRACER_SIZE+1];
 	int i;
 	size_t ret;
 	int err;
 	ret = cnt;
 	if (cnt > MAX_TRACER_SIZE)
 		cnt = MAX_TRACER_SIZE;
 	if (copy_from_user(&buf, ubuf, cnt))
 		return -EFAULT;
 	buf[cnt] = 0;
 	/* strip ending whitespace. */
 	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
 		buf[i] = 0;
 	err = tracing_set_tracer(buf);
 	if (err)
 		return err;
 	*ppos += ret;
 	return ret;
 }
 static ssize_t
 tracing_max_lat_read(struct file *filp, char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
 	unsigned long *ptr = filp->private_data;
 	char buf[64];
 	int r;
 	r = snprintf(buf, sizeof(buf), "%ld\n",
 		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
 	if (r > sizeof(buf))
 		r = sizeof(buf);
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 static ssize_t
 tracing_max_lat_write(struct file *filp, const char __user *ubuf,
 		      size_t cnt, loff_t *ppos)
 {
 	unsigned long *ptr = filp->private_data;
 	char buf[64];
 	unsigned long val;
 	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;
 	*ptr = val * 1000;
 	return cnt;
 }
 static int tracing_open_pipe(struct inode *inode, struct file *filp)
 {
 	long cpu_file = (long) inode->i_private;
 	struct trace_iterator *iter;
 	int ret = 0;
 	if (tracing_disabled)
 		return -ENODEV;
 	mutex_lock(&trace_types_lock);
 	/* create a buffer to store the information to pass to userspace */
 	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
 	if (!iter) {
 		ret = -ENOMEM;
 		goto out;
 	}
 	/*
 	 * We make a copy of the current tracer to avoid concurrent
 	 * changes on it while we are reading.
 	 */
 	iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
 	if (!iter->trace) {
 		ret = -ENOMEM;
 		goto fail;
 	}
 	if (current_trace)
 		*iter->trace = *current_trace;
 	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
 		ret = -ENOMEM;
 		goto fail;
 	}
 	/* trace pipe does not show start of buffer */
 	cpumask_setall(iter->started);
 	if (trace_flags & TRACE_ITER_LATENCY_FMT)
 		iter->iter_flags |= TRACE_FILE_LAT_FMT;
 	iter->cpu_file = cpu_file;
 	iter->tr = &global_trace;
 	mutex_init(&iter->mutex);
 	filp->private_data = iter;
 	if (iter->trace->pipe_open)
 		iter->trace->pipe_open(iter);
 out:
 	mutex_unlock(&trace_types_lock);
 	return ret;
 fail:
 	kfree(iter->trace);
 	kfree(iter);
 	mutex_unlock(&trace_types_lock);
 	return ret;
 }
 static int tracing_release_pipe(struct inode *inode, struct file *file)
 {
 	struct trace_iterator *iter = file->private_data;
 	mutex_lock(&trace_types_lock);
 	if (iter->trace->pipe_close)
 		iter->trace->pipe_close(iter);
 	mutex_unlock(&trace_types_lock);
 	free_cpumask_var(iter->started);
 	mutex_destroy(&iter->mutex);
 	kfree(iter->trace);
 	kfree(iter);
 	return 0;
 }
 static unsigned int
 tracing_poll_pipe(struct file *filp, poll_table *poll_table)
 {
 	struct trace_iterator *iter = filp->private_data;
 	if (trace_flags & TRACE_ITER_BLOCK) {
 		/*
 		 * Always select as readable when in blocking mode
 		 */
 		return POLLIN | POLLRDNORM;
 	} else {
 		if (!trace_empty(iter))
 			return POLLIN | POLLRDNORM;
 		poll_wait(filp, &trace_wait, poll_table);
 		if (!trace_empty(iter))
 			return POLLIN | POLLRDNORM;
 		return 0;
 	}
 }
 void default_wait_pipe(struct trace_iterator *iter)
 {
 	DEFINE_WAIT(wait);
 	prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
 	if (trace_empty(iter))
 		schedule();
 	finish_wait(&trace_wait, &wait);
 }
 /*
  * This is a make-shift waitqueue.
  * A tracer might use this callback on some rare cases:
  *
  *  1) the current tracer might hold the runqueue lock when it wakes up
  *     a reader, hence a deadlock (sched, function, and function graph tracers)
  *  2) the function tracers, trace all functions, we don't want
  *     the overhead of calling wake_up and friends
  *     (and tracing them too)
  *
  *     Anyway, this is really very primitive wakeup.
  */
 void poll_wait_pipe(struct trace_iterator *iter)
 {
 	set_current_state(TASK_INTERRUPTIBLE);
 	/* sleep for 100 msecs, and try again. */
 	schedule_timeout(HZ / 10);
 }
 /* Must be called with trace_types_lock mutex held. */
 static int tracing_wait_pipe(struct file *filp)
 {
 	struct trace_iterator *iter = filp->private_data;
 	while (trace_empty(iter)) {
 		if ((filp->f_flags & O_NONBLOCK)) {
 			return -EAGAIN;
 		}
 		mutex_unlock(&iter->mutex);
 		iter->trace->wait_pipe(iter);
 		mutex_lock(&iter->mutex);
 		if (signal_pending(current))
 			return -EINTR;
 		/*
 		 * We block until we read something and tracing is disabled.
 		 * We still block if tracing is disabled, but we have never
 		 * read anything. This allows a user to cat this file, and
 		 * then enable tracing. But after we have read something,
 		 * we give an EOF when tracing is again disabled.
 		 *
 		 * iter->pos will be 0 if we haven't read anything.
 		 */
 		if (!tracer_enabled && iter->pos)
 			break;
 	}
 	return 1;
 }
 /*
  * Consumer reader.
  */
 static ssize_t
 tracing_read_pipe(struct file *filp, char __user *ubuf,
 		  size_t cnt, loff_t *ppos)
 {
 	struct trace_iterator *iter = filp->private_data;
 	static struct tracer *old_tracer;
 	ssize_t sret;
 	/* return any leftover data */
 	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
 	if (sret != -EBUSY)
 		return sret;
 	trace_seq_init(&iter->seq);
 	/* copy the tracer to avoid using a global lock all around */
 	mutex_lock(&trace_types_lock);
 	if (unlikely(old_tracer != current_trace && current_trace)) {
 		old_tracer = current_trace;
 		*iter->trace = *current_trace;
 	}
 	mutex_unlock(&trace_types_lock);
 	/*
 	 * Avoid more than one consumer on a single file descriptor
 	 * This is just a matter of traces coherency, the ring buffer itself
 	 * is protected.
 	 */
 	mutex_lock(&iter->mutex);
 	if (iter->trace->read) {
 		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
 		if (sret)
 			goto out;
 	}
 waitagain:
 	sret = tracing_wait_pipe(filp);
 	if (sret <= 0)
 		goto out;
 	/* stop when tracing is finished */
 	if (trace_empty(iter)) {
 		sret = 0;
 		goto out;
 	}
 	if (cnt >= PAGE_SIZE)
 		cnt = PAGE_SIZE - 1;
 	/* reset all but tr, trace, and overruns */
 	memset(&iter->seq, 0,
 	       sizeof(struct trace_iterator) -
 	       offsetof(struct trace_iterator, seq));
 	iter->pos = -1;
 	trace_event_read_lock();
 	trace_access_lock(iter->cpu_file);
 	while (find_next_entry_inc(iter) != NULL) {
 		enum print_line_t ret;
 		int len = iter->seq.len;
 		ret = print_trace_line(iter);
 		if (ret == TRACE_TYPE_PARTIAL_LINE) {
 			/* don't print partial lines */
 			iter->seq.len = len;
 			break;
 		}
 		if (ret != TRACE_TYPE_NO_CONSUME)
 			trace_consume(iter);
 		if (iter->seq.len >= cnt)
 			break;
 	}
 	trace_access_unlock(iter->cpu_file);
 	trace_event_read_unlock();
 	/* Now copy what we have to the user */
 	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
 	if (iter->seq.readpos >= iter->seq.len)
 		trace_seq_init(&iter->seq);
 	/*
 	 * If there was nothing to send to user, inspite of consuming trace
 	 * entries, go back to wait for more entries.
 	 */
 	if (sret == -EBUSY)
 		goto waitagain;
 out:
 	mutex_unlock(&iter->mutex);
 	return sret;
 }
 static void tracing_pipe_buf_release(struct pipe_inode_info *pipe,
 				     struct pipe_buffer *buf)
 {
 	__free_page(buf->page);
 }
 static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
 				     unsigned int idx)
 {
 	__free_page(spd->pages[idx]);
 }
 static const struct pipe_buf_operations tracing_pipe_buf_ops = {
 	.can_merge		= 0,
 	.map			= generic_pipe_buf_map,
 	.unmap			= generic_pipe_buf_unmap,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= tracing_pipe_buf_release,
 	.steal			= generic_pipe_buf_steal,
 	.get			= generic_pipe_buf_get,
 };
 static size_t
 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
 {
 	size_t count;
 	int ret;
 	/* Seq buffer is page-sized, exactly what we need. */
 	for (;;) {
 		count = iter->seq.len;
 		ret = print_trace_line(iter);
 		count = iter->seq.len - count;
 		if (rem < count) {
 			rem = 0;
 			iter->seq.len -= count;
 			break;
 		}
 		if (ret == TRACE_TYPE_PARTIAL_LINE) {
 			iter->seq.len -= count;
 			break;
 		}
 		if (ret != TRACE_TYPE_NO_CONSUME)
 			trace_consume(iter);
 		rem -= count;
 		if (!find_next_entry_inc(iter))	{
 			rem = 0;
 			iter->ent = NULL;
 			break;
 		}
 	}
 	return rem;
 }
 static ssize_t tracing_splice_read_pipe(struct file *filp,
 					loff_t *ppos,
 					struct pipe_inode_info *pipe,
 					size_t len,
 					unsigned int flags)
 {
 	struct page *pages[PIPE_BUFFERS];
 	struct partial_page partial[PIPE_BUFFERS];
 	struct trace_iterator *iter = filp->private_data;
 	struct splice_pipe_desc spd = {
 		.pages		= pages,
 		.partial	= partial,
 		.nr_pages	= 0, /* This gets updated below. */
 		.flags		= flags,
 		.ops		= &tracing_pipe_buf_ops,
 		.spd_release	= tracing_spd_release_pipe,
 	};
 	static struct tracer *old_tracer;
 	ssize_t ret;
 	size_t rem;
 	unsigned int i;
 	/* copy the tracer to avoid using a global lock all around */
 	mutex_lock(&trace_types_lock);
 	if (unlikely(old_tracer != current_trace && current_trace)) {
 		old_tracer = current_trace;
 		*iter->trace = *current_trace;
 	}
 	mutex_unlock(&trace_types_lock);
 	mutex_lock(&iter->mutex);
 	if (iter->trace->splice_read) {
 		ret = iter->trace->splice_read(iter, filp,
 					       ppos, pipe, len, flags);
 		if (ret)
 			goto out_err;
 	}
 	ret = tracing_wait_pipe(filp);
 	if (ret <= 0)
 		goto out_err;
 	if (!iter->ent && !find_next_entry_inc(iter)) {
 		ret = -EFAULT;
 		goto out_err;
 	}
 	trace_event_read_lock();
 	trace_access_lock(iter->cpu_file);
 	/* Fill as many pages as possible. */
 	for (i = 0, rem = len; i < PIPE_BUFFERS && rem; i++) {
 		pages[i] = alloc_page(GFP_KERNEL);
 		if (!pages[i])
 			break;
 		rem = tracing_fill_pipe_page(rem, iter);
 		/* Copy the data into the page, so we can start over. */
 		ret = trace_seq_to_buffer(&iter->seq,
 					  page_address(pages[i]),
 					  iter->seq.len);
 		if (ret < 0) {
 			__free_page(pages[i]);
 			break;
 		}
 		partial[i].offset = 0;
 		partial[i].len = iter->seq.len;
 		trace_seq_init(&iter->seq);
 	}
 	trace_access_unlock(iter->cpu_file);
 	trace_event_read_unlock();
 	mutex_unlock(&iter->mutex);
 	spd.nr_pages = i;
 	return splice_to_pipe(pipe, &spd);
 out_err:
 	mutex_unlock(&iter->mutex);
 	return ret;
 }
 static ssize_t
 tracing_entries_read(struct file *filp, char __user *ubuf,
 		     size_t cnt, loff_t *ppos)
 {
 	struct trace_array *tr = filp->private_data;
 	char buf[96];
 	int r;
 	mutex_lock(&trace_types_lock);
 	if (!ring_buffer_expanded)
 		r = sprintf(buf, "%lu (expanded: %lu)\n",
 			    tr->entries >> 10,
 			    trace_buf_size >> 10);
 	else
 		r = sprintf(buf, "%lu\n", tr->entries >> 10);
 	mutex_unlock(&trace_types_lock);
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 }
 static ssize_t
 tracing_entries_write(struct file *filp, const char __user *ubuf,
 		      size_t cnt, loff_t *ppos)
 {
 	unsigned long val;
 	char buf[64];
 	int ret, cpu;
 	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;
 	/* must have at least 1 entry */
 	if (!val)
 		return -EINVAL;
 	mutex_lock(&trace_types_lock);
 	tracing_stop();
 	/* disable all cpu buffers */
 	for_each_tracing_cpu(cpu) {
 		if (global_trace.data[cpu])
 			atomic_inc(&global_trace.data[cpu]->disabled);
 		if (max_tr.data[cpu])
 			atomic_inc(&max_tr.data[cpu]->disabled);
 	}
 	/* value is in KB */
 	val <<= 10;
 	if (val != global_trace.entries) {
 		ret = tracing_resize_ring_buffer(val);
 		if (ret < 0) {
 			cnt = ret;
 			goto out;
 		}
 	}
 	*ppos += cnt;
 	/* If check pages failed, return ENOMEM */
 	if (tracing_disabled)
 		cnt = -ENOMEM;
  out:
 	for_each_tracing_cpu(cpu) {
 		if (global_trace.data[cpu])
 			atomic_dec(&global_trace.data[cpu]->disabled);
 		if (max_tr.data[cpu])
 			atomic_dec(&max_tr.data[cpu]->disabled);
 	}
 	tracing_start();
 	max_tr.entries = global_trace.entries;
 	mutex_unlock(&trace_types_lock);
 	return cnt;
 }
 static int mark_printk(const char *fmt, ...)
 {
 	int ret;
 	va_list args;
 	va_start(args, fmt);
 	ret = trace_vprintk(0, fmt, args);
 	va_end(args);
 	return ret;
 }
 static ssize_t
 tracing_mark_write(struct file *filp, const char __user *ubuf,
 					size_t cnt, loff_t *fpos)
 {
 	char *buf;
 	if (tracing_disabled)
 		return -EINVAL;
 	if (cnt > TRACE_BUF_SIZE)
 		cnt = TRACE_BUF_SIZE;
 	buf = kmalloc(cnt + 2, GFP_KERNEL);
 	if (buf == NULL)
 		return -ENOMEM;
 	if (copy_from_user(buf, ubuf, cnt)) {
 		kfree(buf);
 		return -EFAULT;
 	}
 	if (buf[cnt-1] != '\n') {
 		buf[cnt] = '\n';
 		buf[cnt+1] = '\0';
 	} else
 		buf[cnt] = '\0';
 	cnt = mark_printk("%s", buf);
 	kfree(buf);
 	*fpos += cnt;
 	return cnt;
 }
 static int tracing_clock_show(struct seq_file *m, void *v)
 {
 	int i;
 	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
 		seq_printf(m,
 			"%s%s%s%s", i ? " " : "",
 			i == trace_clock_id ? "[" : "", trace_clocks[i].name,
 			i == trace_clock_id ? "]" : "");
 	seq_putc(m, '\n');
 	return 0;
 }
 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 int tracing_clock_open(struct inode *inode, struct file *file)
 {
 	if (tracing_disabled)
 		return -ENODEV;
 	return single_open(file, tracing_clock_show, NULL);
 }
 static const struct file_operations tracing_max_lat_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_max_lat_read,
 	.write		= tracing_max_lat_write,
 };
 static const struct file_operations tracing_ctrl_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_ctrl_read,
 	.write		= tracing_ctrl_write,
 };
 static const struct file_operations set_tracer_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_set_trace_read,
 	.write		= tracing_set_trace_write,
 };
 static const struct file_operations tracing_pipe_fops = {
 	.open		= tracing_open_pipe,
 	.poll		= tracing_poll_pipe,
 	.read		= tracing_read_pipe,
 	.splice_read	= tracing_splice_read_pipe,
 	.release	= tracing_release_pipe,
 };
 static const struct file_operations tracing_entries_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_entries_read,
 	.write		= tracing_entries_write,
 };
 static const struct file_operations tracing_mark_fops = {
 	.open		= tracing_open_generic,
 	.write		= tracing_mark_write,
 };
 static const struct file_operations trace_clock_fops = {
 	.open		= tracing_clock_open,
 	.read		= seq_read,
 	.llseek		= seq_lseek,
 	.release	= single_release,
 	.write		= tracing_clock_write,
 };
 struct ftrace_buffer_info {
 	struct trace_array	*tr;
 	void			*spare;
 	int			cpu;
 	unsigned int		read;
 };
 static int tracing_buffers_open(struct inode *inode, struct file *filp)
 {
 	int cpu = (int)(long)inode->i_private;
 	struct ftrace_buffer_info *info;
 	if (tracing_disabled)
 		return -ENODEV;
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
 		return -ENOMEM;
 	info->tr	= &global_trace;
 	info->cpu	= cpu;
 	info->spare	= NULL;
 	/* Force reading ring buffer for first read */
 	info->read	= (unsigned int)-1;
 	filp->private_data = info;
 	return nonseekable_open(inode, filp);
 }
 static ssize_t
 tracing_buffers_read(struct file *filp, char __user *ubuf,
 		     size_t count, loff_t *ppos)
 {
 	struct ftrace_buffer_info *info = filp->private_data;
 	unsigned int pos;
 	ssize_t ret;
 	size_t size;
 	if (!count)
 		return 0;
 	if (!info->spare)
 		info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
 	if (!info->spare)
 		return -ENOMEM;
 	/* Do we have previous read data to read? */
 	if (info->read < PAGE_SIZE)
 		goto read;
 	info->read = 0;
 	trace_access_lock(info->cpu);
 	ret = ring_buffer_read_page(info->tr->buffer,
 				    &info->spare,
 				    count,
 				    info->cpu, 0);
 	trace_access_unlock(info->cpu);
 	if (ret < 0)
 		return 0;
 	pos = ring_buffer_page_len(info->spare);
 	if (pos < PAGE_SIZE)
 		memset(info->spare + pos, 0, PAGE_SIZE - pos);
 read:
 	size = PAGE_SIZE - info->read;
 	if (size > count)
 		size = count;
 	ret = copy_to_user(ubuf, info->spare + info->read, size);
 	if (ret == size)
 		return -EFAULT;
 	size -= ret;
 	*ppos += size;
 	info->read += size;
 	return size;
 }
 static int tracing_buffers_release(struct inode *inode, struct file *file)
 {
 	struct ftrace_buffer_info *info = file->private_data;
 	if (info->spare)
 		ring_buffer_free_read_page(info->tr->buffer, info->spare);
 	kfree(info);
 	return 0;
 }
 struct buffer_ref {
 	struct ring_buffer	*buffer;
 	void			*page;
 	int			ref;
 };
 static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
 				    struct pipe_buffer *buf)
 {
 	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
 	if (--ref->ref)
 		return;
 	ring_buffer_free_read_page(ref->buffer, ref->page);
 	kfree(ref);
 	buf->private = 0;
 }
 static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
 				 struct pipe_buffer *buf)
 {
 	return 1;
 }
 static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
 				struct pipe_buffer *buf)
 {
 	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
 	ref->ref++;
 }
 /* Pipe buffer operations for a buffer. */
 static const struct pipe_buf_operations buffer_pipe_buf_ops = {
 	.can_merge		= 0,
 	.map			= generic_pipe_buf_map,
 	.unmap			= generic_pipe_buf_unmap,
 	.confirm		= generic_pipe_buf_confirm,
 	.release		= buffer_pipe_buf_release,
 	.steal			= buffer_pipe_buf_steal,
 	.get			= buffer_pipe_buf_get,
 };
 /*
  * Callback from splice_to_pipe(), if we need to release some pages
  * at the end of the spd in case we error'ed out in filling the pipe.
  */
 static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
 {
 	struct buffer_ref *ref =
 		(struct buffer_ref *)spd->partial[i].private;
 	if (--ref->ref)
 		return;
 	ring_buffer_free_read_page(ref->buffer, ref->page);
 	kfree(ref);
 	spd->partial[i].private = 0;
 }
 static ssize_t
 tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 			    struct pipe_inode_info *pipe, size_t len,
 			    unsigned int flags)
 {
 	struct ftrace_buffer_info *info = file->private_data;
 	struct partial_page partial[PIPE_BUFFERS];
 	struct page *pages[PIPE_BUFFERS];
 	struct splice_pipe_desc spd = {
 		.pages		= pages,
 		.partial	= partial,
 		.flags		= flags,
 		.ops		= &buffer_pipe_buf_ops,
 		.spd_release	= buffer_spd_release,
 	};
 	struct buffer_ref *ref;
 	int entries, size, i;
 	size_t ret;
 	if (*ppos & (PAGE_SIZE - 1)) {
 		WARN_ONCE(1, "Ftrace: previous read must page-align\n");
 		return -EINVAL;
 	}
 	if (len & (PAGE_SIZE - 1)) {
 		WARN_ONCE(1, "Ftrace: splice_read should page-align\n");
 		if (len < PAGE_SIZE)
 			return -EINVAL;
 		len &= PAGE_MASK;
 	}
 	trace_access_lock(info->cpu);
 	entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
 	for (i = 0; i < PIPE_BUFFERS && len && entries; i++, len -= PAGE_SIZE) {
 		struct page *page;
 		int r;
 		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
 		if (!ref)
 			break;
 		ref->ref = 1;
 		ref->buffer = info->tr->buffer;
 		ref->page = ring_buffer_alloc_read_page(ref->buffer);
 		if (!ref->page) {
 			kfree(ref);
 			break;
 		}
 		r = ring_buffer_read_page(ref->buffer, &ref->page,
 					  len, info->cpu, 1);
 		if (r < 0) {
 			ring_buffer_free_read_page(ref->buffer,
 						   ref->page);
 			kfree(ref);
 			break;
 		}
 		/*
 		 * zero out any left over data, this is going to
 		 * user land.
 		 */
 		size = ring_buffer_page_len(ref->page);
 		if (size < PAGE_SIZE)
 			memset(ref->page + size, 0, PAGE_SIZE - size);
 		page = virt_to_page(ref->page);
 		spd.pages[i] = page;
 		spd.partial[i].len = PAGE_SIZE;
 		spd.partial[i].offset = 0;
 		spd.partial[i].private = (unsigned long)ref;
 		spd.nr_pages++;
 		*ppos += PAGE_SIZE;
 		entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
 	}
 	trace_access_unlock(info->cpu);
 	spd.nr_pages = i;
 	/* did we read anything? */
 	if (!spd.nr_pages) {
 		if (flags & SPLICE_F_NONBLOCK)
 			ret = -EAGAIN;
 		else
 			ret = 0;
 		/* TODO: block */
 		return ret;
 	}
 	ret = splice_to_pipe(pipe, &spd);
 	return ret;
 }
 static const struct file_operations tracing_buffers_fops = {
 	.open		= tracing_buffers_open,
 	.read		= tracing_buffers_read,
 	.release	= tracing_buffers_release,
 	.splice_read	= tracing_buffers_splice_read,
 	.llseek		= no_llseek,
 };
 static ssize_t
 tracing_stats_read(struct file *filp, char __user *ubuf,
 		   size_t count, loff_t *ppos)
 {
 	unsigned long cpu = (unsigned long)filp->private_data;
 	struct trace_array *tr = &global_trace;
 	struct trace_seq *s;
 	unsigned long cnt;
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (!s)
 		return -ENOMEM;
 	trace_seq_init(s);
 	cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
 	trace_seq_printf(s, "entries: %ld\n", cnt);
 	cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
 	trace_seq_printf(s, "overrun: %ld\n", cnt);
 	cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
 	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
 	count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
 	kfree(s);
 	return count;
 }
 static const struct file_operations tracing_stats_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_stats_read,
 };
 #ifdef CONFIG_DYNAMIC_FTRACE
 int __weak ftrace_arch_read_dyn_info(char *buf, int size)
 {
 	return 0;
 }
 static ssize_t
 tracing_read_dyn_info(struct file *filp, char __user *ubuf,
 		  size_t cnt, loff_t *ppos)
 {
 	static char ftrace_dyn_info_buffer[1024];
 	static DEFINE_MUTEX(dyn_info_mutex);
 	unsigned long *p = filp->private_data;
 	char *buf = ftrace_dyn_info_buffer;
 	int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
 	int r;
 	mutex_lock(&dyn_info_mutex);
 	r = sprintf(buf, "%ld ", *p);
 	r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
 	buf[r++] = '\n';
 	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 	mutex_unlock(&dyn_info_mutex);
 	return r;
 }
 static const struct file_operations tracing_dyn_info_fops = {
 	.open		= tracing_open_generic,
 	.read		= tracing_read_dyn_info,
 };
 #endif
 static struct dentry *d_tracer;
 struct dentry *tracing_init_dentry(void)
 {
 	static int once;
 	if (d_tracer)
 		return d_tracer;
 	if (!debugfs_initialized())
 		return NULL;
 	d_tracer = debugfs_create_dir("tracing", NULL);
 	if (!d_tracer && !once) {
 		once = 1;
 		pr_warning("Could not create debugfs directory 'tracing'\n");
 		return NULL;
 	}
 	return d_tracer;
 }
 static struct dentry *d_percpu;
 struct dentry *tracing_dentry_percpu(void)
 {
 	static int once;
 	struct dentry *d_tracer;
 	if (d_percpu)
 		return d_percpu;
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
 		return NULL;
 	d_percpu = debugfs_create_dir("per_cpu", d_tracer);
 	if (!d_percpu && !once) {
 		once = 1;
 		pr_warning("Could not create debugfs directory 'per_cpu'\n");
 		return NULL;
 	}
 	return d_percpu;
 }
 static void tracing_init_debugfs_percpu(long cpu)
 {
 	struct dentry *d_percpu = tracing_dentry_percpu();
 	struct dentry *d_cpu;
 	/* strlen(cpu) + MAX(log10(cpu)) + '\0' */
 	char cpu_dir[7];
 	if (cpu > 999 || cpu < 0)
 		return;
 	sprintf(cpu_dir, "cpu%ld", cpu);
 	d_cpu = debugfs_create_dir(cpu_dir, d_percpu);
 	if (!d_cpu) {
 		pr_warning("Could not create debugfs '%s' entry\n", cpu_dir);
 		return;
 	}
 	/* per cpu trace_pipe */
 	trace_create_file("trace_pipe", 0444, d_cpu,
 			(void *) cpu, &tracing_pipe_fops);
 	/* per cpu trace */
 	trace_create_file("trace", 0644, d_cpu,
 			(void *) cpu, &tracing_fops);
 	trace_create_file("trace_pipe_raw", 0444, d_cpu,
 			(void *) cpu, &tracing_buffers_fops);
 	trace_create_file("stats", 0444, d_cpu,
 			(void *) cpu, &tracing_stats_fops);
 }
 #ifdef CONFIG_FTRACE_SELFTEST
 /* Let selftest have access to static functions in this file */
 #include "trace_selftest.c"
 #endif
 struct trace_option_dentry {
 	struct tracer_opt		*opt;
 	struct tracer_flags		*flags;
 	struct dentry			*entry;
 };
 static ssize_t
 trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
 			loff_t *ppos)
 {
 	struct trace_option_dentry *topt = filp->private_data;
 	char *buf;
 	if (topt->flags->val & topt->opt->bit)
 		buf = "1\n";
 	else
 		buf = "0\n";
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 }
 static ssize_t
 trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
 			 loff_t *ppos)
 {
 	struct trace_option_dentry *topt = filp->private_data;
 	unsigned long val;
 	char buf[64];
 	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;
 	if (val != 0 && val != 1)
 		return -EINVAL;
 	if (!!(topt->flags->val & topt->opt->bit) != val) {
 		mutex_lock(&trace_types_lock);
 		ret = __set_tracer_option(current_trace, topt->flags,
 					  topt->opt, !val);
 		mutex_unlock(&trace_types_lock);
 		if (ret)
 			return ret;
 	}
 	*ppos += cnt;
 	return cnt;
 }
 static const struct file_operations trace_options_fops = {
 	.open = tracing_open_generic,
 	.read = trace_options_read,
 	.write = trace_options_write,
 };
 static ssize_t
 trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
 			loff_t *ppos)
 {
 	long index = (long)filp->private_data;
 	char *buf;
 	if (trace_flags & (1 << index))
 		buf = "1\n";
 	else
 		buf = "0\n";
 	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
 }
 static ssize_t
 trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
 			 loff_t *ppos)
 {
 	long index = (long)filp->private_data;
 	char buf[64];
 	unsigned long val;
 	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;
 	if (val != 0 && val != 1)
 		return -EINVAL;
 	set_tracer_flags(1 << index, val);
 	*ppos += cnt;
 	return cnt;
 }
 static const struct file_operations trace_options_core_fops = {
 	.open = tracing_open_generic,
 	.read = trace_options_core_read,
 	.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;
 	static struct dentry *t_options;
 	if (t_options)
 		return t_options;
 	d_tracer = tracing_init_dentry();
 	if (!d_tracer)
 		return NULL;
 	t_options = debugfs_create_dir("options", d_tracer);
 	if (!t_options) {
 		pr_warning("Could not create debugfs directory 'options'\n");
 		return NULL;
 	}
 	return t_options;
 }
 static void
 create_trace_option_file(struct trace_option_dentry *topt,
 			 struct tracer_flags *flags,
 			 struct tracer_opt *opt)
 {
 	struct dentry *t_options;
 	t_options = trace_options_init_dentry();
 	if (!t_options)
 		return;
 	topt->flags = flags;
 	topt->opt = opt;
 	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
 				    &trace_options_fops);
 }
 static struct trace_option_dentry *
 create_trace_option_files(struct tracer *tracer)
 {
 	struct trace_option_dentry *topts;
 	struct tracer_flags *flags;
 	struct tracer_opt *opts;
 	int cnt;
 	if (!tracer)
 		return NULL;
 	flags = tracer->flags;
 	if (!flags || !flags->opts)
 		return NULL;
 	opts = flags->opts;
 	for (cnt = 0; opts[cnt].name; cnt++)
 		;
 	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
 	if (!topts)
 		return NULL;
 	for (cnt = 0; opts[cnt].name; cnt++)
 		create_trace_option_file(&topts[cnt], flags,
 					 &opts[cnt]);
 	return topts;
 }
 static void
 destroy_trace_option_files(struct trace_option_dentry *topts)
 {
 	int cnt;
 	if (!topts)
 		return;
 	for (cnt = 0; topts[cnt].opt; cnt++) {
 		if (topts[cnt].entry)
 			debugfs_remove(topts[cnt].entry);
 	}
 	kfree(topts);
 }
 static struct dentry *
 create_trace_option_core_file(const char *option, long index)
 {
 	struct dentry *t_options;
 	t_options = trace_options_init_dentry();
 	if (!t_options)
 		return NULL;
 	return trace_create_file(option, 0644, t_options, (void *)index,
 				    &trace_options_core_fops);
 }
 static __init void create_trace_options_dir(void)
 {
 	struct dentry *t_options;
 	int i;
 	t_options = trace_options_init_dentry();
 	if (!t_options)
 		return;
 	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;
 	int cpu;
 	trace_access_lock_init();
 	d_tracer = tracing_init_dentry();
 	trace_create_file("tracing_enabled", 0644, d_tracer,
 			&global_trace, &tracing_ctrl_fops);
 	trace_create_file("trace_options", 0644, d_tracer,
 			NULL, &tracing_iter_fops);
 	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", 0644, d_tracer,
 			&global_trace, &set_tracer_fops);
 #ifdef CONFIG_TRACER_MAX_TRACE
 	trace_create_file("tracing_max_latency", 0644, d_tracer,
 			&tracing_max_latency, &tracing_max_lat_fops);
+#endif
 	trace_create_file("tracing_thresh", 0644, d_tracer,
 			&tracing_thresh, &tracing_max_lat_fops);
-#endif
 	trace_create_file("README", 0444, d_tracer,
 			NULL, &tracing_readme_fops);
 	trace_create_file("trace_pipe", 0444, d_tracer,
 			(void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
 	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);
 	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);
 #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);
 	return 0;
 }
 static int trace_panic_handler(struct notifier_block *this,
 			       unsigned long event, void *unused)
 {
 	if (ftrace_dump_on_oops)
 		ftrace_dump();
 	return NOTIFY_OK;
 }
 static struct notifier_block trace_panic_notifier = {
 	.notifier_call  = trace_panic_handler,
 	.next           = NULL,
 	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
 };
 static int trace_die_handler(struct notifier_block *self,
 			     unsigned long val,
 			     void *data)
 {
 	switch (val) {
 	case DIE_OOPS:
 		if (ftrace_dump_on_oops)
 			ftrace_dump();
 		break;
 	default:
 		break;
 	}
 	return NOTIFY_OK;
 }
 static struct notifier_block trace_die_notifier = {
 	.notifier_call = trace_die_handler,
 	.priority = 200
 };
 /*
  * printk is set to max of 1024, we really don't need it that big.
  * Nothing should be printing 1000 characters anyway.
  */
 #define TRACE_MAX_PRINT		1000
 /*
  * Define here KERN_TRACE so that we have one place to modify
  * it if we decide to change what log level the ftrace dump
  * should be at.
  */
 #define KERN_TRACE		KERN_EMERG
 static void
 trace_printk_seq(struct trace_seq *s)
 {
 	/* Probably should print a warning here. */
 	if (s->len >= 1000)
 		s->len = 1000;
 	/* should be zero ended, but we are paranoid. */
 	s->buffer[s->len] = 0;
 	printk(KERN_TRACE "%s", s->buffer);
 	trace_seq_init(s);
 }
 static void __ftrace_dump(bool disable_tracing)
 {
 	static arch_spinlock_t ftrace_dump_lock =
 		(arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 	/* use static because iter can be a bit big for the stack */
 	static struct trace_iterator iter;
 	unsigned int old_userobj;
 	static int dump_ran;
 	unsigned long flags;
 	int cnt = 0, cpu;
 	/* only one dump */
 	local_irq_save(flags);
 	arch_spin_lock(&ftrace_dump_lock);
 	if (dump_ran)
 		goto out;
 	dump_ran = 1;
 	tracing_off();
 	if (disable_tracing)
 		ftrace_kill();
 	for_each_tracing_cpu(cpu) {
 		atomic_inc(&global_trace.data[cpu]->disabled);
 	}
 	old_userobj = trace_flags & TRACE_ITER_SYM_USEROBJ;
 	/* don't look at user memory in panic mode */
 	trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
 	printk(KERN_TRACE "Dumping ftrace buffer:\n");
 	/* Simulate the iterator */
 	iter.tr = &global_trace;
 	iter.trace = current_trace;
 	iter.cpu_file = TRACE_PIPE_ALL_CPU;
 	/*
 	 * We need to stop all tracing on all CPUS to read the
 	 * the next buffer. This is a bit expensive, but is
 	 * not done often. We fill all what we can read,
 	 * and then release the locks again.
 	 */
 	while (!trace_empty(&iter)) {
 		if (!cnt)
 			printk(KERN_TRACE "---------------------------------\n");
 		cnt++;
 		/* reset all but tr, trace, and overruns */
 		memset(&iter.seq, 0,
 		       sizeof(struct trace_iterator) -
 		       offsetof(struct trace_iterator, seq));
 		iter.iter_flags |= TRACE_FILE_LAT_FMT;
 		iter.pos = -1;
 		if (find_next_entry_inc(&iter) != NULL) {
 			int ret;
 			ret = print_trace_line(&iter);
 			if (ret != TRACE_TYPE_NO_CONSUME)
 				trace_consume(&iter);
 		}
 		trace_printk_seq(&iter.seq);
 	}
 	if (!cnt)
 		printk(KERN_TRACE "   (ftrace buffer empty)\n");
 	else
 		printk(KERN_TRACE "---------------------------------\n");
 	/* Re-enable tracing if requested */
 	if (!disable_tracing) {
 		trace_flags |= old_userobj;
 		for_each_tracing_cpu(cpu) {
 			atomic_dec(&global_trace.data[cpu]->disabled);
 		}
 		tracing_on();
 	}
  out:
 	arch_spin_unlock(&ftrace_dump_lock);
 	local_irq_restore(flags);
 }
 /* By default: disable tracing after the dump */
 void ftrace_dump(void)
 {
 	__ftrace_dump(true);
 }
 __init static int tracer_alloc_buffers(void)
 {
 	int ring_buf_size;
 	int i;
 	int ret = -ENOMEM;
 	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
 		goto out;
 	if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
 		goto out_free_buffer_mask;
 	/* To save memory, keep the ring buffer size to its minimum */
 	if (ring_buffer_expanded)
 		ring_buf_size = trace_buf_size;
 	else
 		ring_buf_size = 1;
 	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
 	cpumask_copy(tracing_cpumask, cpu_all_mask);
 	/* TODO: make the number of buffers hot pluggable with CPUS */
 	global_trace.buffer = ring_buffer_alloc(ring_buf_size,
 						   TRACE_BUFFER_FLAGS);
 	if (!global_trace.buffer) {
 		printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
 		WARN_ON(1);
 		goto out_free_cpumask;
 	}
 	global_trace.entries = ring_buffer_size(global_trace.buffer);
 #ifdef CONFIG_TRACER_MAX_TRACE
 	max_tr.buffer = ring_buffer_alloc(ring_buf_size,
 					     TRACE_BUFFER_FLAGS);
 	if (!max_tr.buffer) {
 		printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
 		WARN_ON(1);
 		ring_buffer_free(global_trace.buffer);
 		goto out_free_cpumask;
 	}
 	max_tr.entries = ring_buffer_size(max_tr.buffer);
 	WARN_ON(max_tr.entries != global_trace.entries);
 #endif
 	/* Allocate the first page for all buffers */
 	for_each_tracing_cpu(i) {
 		global_trace.data[i] = &per_cpu(global_trace_cpu, i);
 		max_tr.data[i] = &per_cpu(max_tr_data, i);
 	}
 	trace_init_cmdlines();
 	register_tracer(&nop_trace);
 	current_trace = &nop_trace;
 #ifdef CONFIG_BOOT_TRACER
 	register_tracer(&boot_tracer);
 #endif
 	/* All seems OK, enable tracing */
 	tracing_disabled = 0;
 	atomic_notifier_chain_register(&panic_notifier_list,
 				       &trace_panic_notifier);
 	register_die_notifier(&trace_die_notifier);
 	return 0;
 out_free_cpumask:
 	free_cpumask_var(tracing_cpumask);
 out_free_buffer_mask:
 	free_cpumask_var(tracing_buffer_mask);
 out:
 	return ret;
 }
 __init static int clear_boot_tracer(void)
 {
 	/*
 	 * The default tracer at boot buffer is an init section.
 	 * This function is called in lateinit. If we did not
 	 * find the boot tracer, then clear it out, to prevent
 	 * later registration from accessing the buffer that is
 	 * about to be freed.
 	 */
 	if (!default_bootup_tracer)
 		return 0;
 	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
 	       default_bootup_tracer);
 	default_bootup_tracer = NULL;
 	return 0;
 }
 early_initcall(tracer_alloc_buffers);
 fs_initcall(tracer_init_debugfs);

kernel/trace/trace.h

Diff comments View file @ 915a0b5

 #ifndef _LINUX_KERNEL_TRACE_H
 #define _LINUX_KERNEL_TRACE_H
 #include <linux/fs.h>
 #include <asm/atomic.h>
 #include <linux/sched.h>
 #include <linux/clocksource.h>
 #include <linux/ring_buffer.h>
 #include <linux/mmiotrace.h>
 #include <linux/tracepoint.h>
 #include <linux/ftrace.h>
 #include <trace/boot.h>
 #include <linux/kmemtrace.h>
 #include <linux/hw_breakpoint.h>
 #include <linux/trace_seq.h>
 #include <linux/ftrace_event.h>
 enum trace_type {
 	__TRACE_FIRST_TYPE = 0,
 	TRACE_FN,
 	TRACE_CTX,
 	TRACE_WAKE,
 	TRACE_STACK,
 	TRACE_PRINT,
 	TRACE_BPRINT,
 	TRACE_SPECIAL,
 	TRACE_MMIO_RW,
 	TRACE_MMIO_MAP,
 	TRACE_BRANCH,
 	TRACE_BOOT_CALL,
 	TRACE_BOOT_RET,
 	TRACE_GRAPH_RET,
 	TRACE_GRAPH_ENT,
 	TRACE_USER_STACK,
 	TRACE_HW_BRANCHES,
 	TRACE_KMEM_ALLOC,
 	TRACE_KMEM_FREE,
 	TRACE_BLK,
 	TRACE_KSYM,
 	__TRACE_LAST_TYPE,
 };
 enum kmemtrace_type_id {
 	KMEMTRACE_TYPE_KMALLOC = 0,	/* kmalloc() or kfree(). */
 	KMEMTRACE_TYPE_CACHE,		/* kmem_cache_*(). */
 	KMEMTRACE_TYPE_PAGES,		/* __get_free_pages() and friends. */
 };
 extern struct tracer boot_tracer;
 #undef __field
 #define __field(type, item)		type	item;
 #undef __field_struct
 #define __field_struct(type, item)	__field(type, item)
 #undef __field_desc
 #define __field_desc(type, container, item)
 #undef __array
 #define __array(type, item, size)	type	item[size];
 #undef __array_desc
 #define __array_desc(type, container, item, size)
 #undef __dynamic_array
 #define __dynamic_array(type, item)	type	item[];
 #undef F_STRUCT
 #define F_STRUCT(args...)		args
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(name, struct_name, id, tstruct, print)	\
 	struct struct_name {					\
 		struct trace_entry	ent;			\
 		tstruct						\
 	}
 #undef TP_ARGS
 #define TP_ARGS(args...)	args
 #undef FTRACE_ENTRY_DUP
 #define FTRACE_ENTRY_DUP(name, name_struct, id, tstruct, printk)
 #include "trace_entries.h"
 /*
  * syscalls are special, and need special handling, this is why
  * they are not included in trace_entries.h
  */
 struct syscall_trace_enter {
 	struct trace_entry	ent;
 	int			nr;
 	unsigned long		args[];
 };
 struct syscall_trace_exit {
 	struct trace_entry	ent;
 	int			nr;
 	long			ret;
 };
 struct kprobe_trace_entry {
 	struct trace_entry	ent;
 	unsigned long		ip;
 	int			nargs;
 	unsigned long		args[];
 };
 #define SIZEOF_KPROBE_TRACE_ENTRY(n)			\
 	(offsetof(struct kprobe_trace_entry, args) +	\
 	(sizeof(unsigned long) * (n)))
 struct kretprobe_trace_entry {
 	struct trace_entry	ent;
 	unsigned long		func;
 	unsigned long		ret_ip;
 	int			nargs;
 	unsigned long		args[];
 };
 #define SIZEOF_KRETPROBE_TRACE_ENTRY(n)			\
 	(offsetof(struct kretprobe_trace_entry, args) +	\
 	(sizeof(unsigned long) * (n)))
 /*
  * trace_flag_type is an enumeration that holds different
  * states when a trace occurs. These are:
  *  IRQS_OFF		- interrupts were disabled
  *  IRQS_NOSUPPORT	- arch does not support irqs_disabled_flags
  *  NEED_RESCHED	- reschedule is requested
  *  HARDIRQ		- inside an interrupt handler
  *  SOFTIRQ		- inside a softirq handler
  */
 enum trace_flag_type {
 	TRACE_FLAG_IRQS_OFF		= 0x01,
 	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
 	TRACE_FLAG_NEED_RESCHED		= 0x04,
 	TRACE_FLAG_HARDIRQ		= 0x08,
 	TRACE_FLAG_SOFTIRQ		= 0x10,
 };
 #define TRACE_BUF_SIZE		1024
 /*
  * The CPU trace array - it consists of thousands of trace entries
  * plus some other descriptor data: (for example which task started
  * the trace, etc.)
  */
 struct trace_array_cpu {
 	atomic_t		disabled;
 	void			*buffer_page;	/* ring buffer spare */
 	unsigned long		saved_latency;
 	unsigned long		critical_start;
 	unsigned long		critical_end;
 	unsigned long		critical_sequence;
 	unsigned long		nice;
 	unsigned long		policy;
 	unsigned long		rt_priority;
 	unsigned long		skipped_entries;
 	cycle_t			preempt_timestamp;
 	pid_t			pid;
 	uid_t			uid;
 	char			comm[TASK_COMM_LEN];
 };
 /*
  * The trace array - an array of per-CPU trace arrays. This is the
  * highest level data structure that individual tracers deal with.
  * They have on/off state as well:
  */
 struct trace_array {
 	struct ring_buffer	*buffer;
 	unsigned long		entries;
 	int			cpu;
 	cycle_t			time_start;
 	struct task_struct	*waiter;
 	struct trace_array_cpu	*data[NR_CPUS];
 };
 #define FTRACE_CMP_TYPE(var, type) \
 	__builtin_types_compatible_p(typeof(var), type *)
 #undef IF_ASSIGN
 #define IF_ASSIGN(var, entry, etype, id)		\
 	if (FTRACE_CMP_TYPE(var, etype)) {		\
 		var = (typeof(var))(entry);		\
 		WARN_ON(id && (entry)->type != id);	\
 		break;					\
 	}
 /* Will cause compile errors if type is not found. */
 extern void __ftrace_bad_type(void);
 /*
  * The trace_assign_type is a verifier that the entry type is
  * the same as the type being assigned. To add new types simply
  * add a line with the following format:
  *
  * IF_ASSIGN(var, ent, type, id);
  *
  *  Where "type" is the trace type that includes the trace_entry
  *  as the "ent" item. And "id" is the trace identifier that is
  *  used in the trace_type enum.
  *
  *  If the type can have more than one id, then use zero.
  */
 #define trace_assign_type(var, ent)					\
 	do {								\
 		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
 		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
 		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
 		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_STACK);\
 		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
 		IF_ASSIGN(var, ent, struct bprint_entry, TRACE_BPRINT);	\
 		IF_ASSIGN(var, ent, struct special_entry, 0);		\
 		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
 			  TRACE_MMIO_RW);				\
 		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
 			  TRACE_MMIO_MAP);				\
 		IF_ASSIGN(var, ent, struct trace_boot_call, TRACE_BOOT_CALL);\
 		IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
 		IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
 		IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,	\
 			  TRACE_GRAPH_ENT);		\
 		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
 			  TRACE_GRAPH_RET);		\
 		IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
 		IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,	\
 			  TRACE_KMEM_ALLOC);	\
 		IF_ASSIGN(var, ent, struct kmemtrace_free_entry,	\
 			  TRACE_KMEM_FREE);	\
 		IF_ASSIGN(var, ent, struct ksym_trace_entry, TRACE_KSYM);\
 		__ftrace_bad_type();					\
 	} while (0)
 /*
  * An option specific to a tracer. This is a boolean value.
  * The bit is the bit index that sets its value on the
  * flags value in struct tracer_flags.
  */
 struct tracer_opt {
 	const char	*name; /* Will appear on the trace_options file */
 	u32		bit; /* Mask assigned in val field in tracer_flags */
 };
 /*
  * The set of specific options for a tracer. Your tracer
  * have to set the initial value of the flags val.
  */
 struct tracer_flags {
 	u32			val;
 	struct tracer_opt	*opts;
 };
 /* Makes more easy to define a tracer opt */
 #define TRACER_OPT(s, b)	.name = #s, .bit = b
 /**
  * struct tracer - a specific tracer and its callbacks to interact with debugfs
  * @name: the name chosen to select it on the available_tracers file
  * @init: called when one switches to this tracer (echo name > current_tracer)
  * @reset: called when one switches to another tracer
  * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
  * @stop: called when tracing is paused (echo 0 > tracing_enabled)
  * @open: called when the trace file is opened
  * @pipe_open: called when the trace_pipe file is opened
  * @wait_pipe: override how the user waits for traces on trace_pipe
  * @close: called when the trace file is released
  * @pipe_close: called when the trace_pipe file is released
  * @read: override the default read callback on trace_pipe
  * @splice_read: override the default splice_read callback on trace_pipe
  * @selftest: selftest to run on boot (see trace_selftest.c)
  * @print_headers: override the first lines that describe your columns
  * @print_line: callback that prints a trace
  * @set_flag: signals one of your private flags changed (trace_options file)
  * @flags: your private flags
  */
 struct tracer {
 	const char		*name;
 	int			(*init)(struct trace_array *tr);
 	void			(*reset)(struct trace_array *tr);
 	void			(*start)(struct trace_array *tr);
 	void			(*stop)(struct trace_array *tr);
 	void			(*open)(struct trace_iterator *iter);
 	void			(*pipe_open)(struct trace_iterator *iter);
 	void			(*wait_pipe)(struct trace_iterator *iter);
 	void			(*close)(struct trace_iterator *iter);
 	void			(*pipe_close)(struct trace_iterator *iter);
 	ssize_t			(*read)(struct trace_iterator *iter,
 					struct file *filp, char __user *ubuf,
 					size_t cnt, loff_t *ppos);
 	ssize_t			(*splice_read)(struct trace_iterator *iter,
 					       struct file *filp,
 					       loff_t *ppos,
 					       struct pipe_inode_info *pipe,
 					       size_t len,
 					       unsigned int flags);
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 	int			(*selftest)(struct tracer *trace,
 					    struct trace_array *tr);
 #endif
 	void			(*print_header)(struct seq_file *m);
 	enum print_line_t	(*print_line)(struct trace_iterator *iter);
 	/* If you handled the flag setting, return 0 */
 	int			(*set_flag)(u32 old_flags, u32 bit, int set);
 	struct tracer		*next;
 	int			print_max;
 	struct tracer_flags	*flags;
 };
 #define TRACE_PIPE_ALL_CPU	-1
 int tracer_init(struct tracer *t, struct trace_array *tr);
 int tracing_is_enabled(void);
 void trace_wake_up(void);
 void tracing_reset(struct trace_array *tr, int cpu);
 void tracing_reset_online_cpus(struct trace_array *tr);
 void tracing_reset_current(int cpu);
 void tracing_reset_current_online_cpus(void);
 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);
 struct ring_buffer_event;
 struct ring_buffer_event *
 trace_buffer_lock_reserve(struct ring_buffer *buffer,
 			  int type,
 			  unsigned long len,
 			  unsigned long flags,
 			  int pc);
 void trace_buffer_unlock_commit(struct ring_buffer *buffer,
 				struct ring_buffer_event *event,
 				unsigned long flags, int pc);
 struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
 						struct trace_array_cpu *data);
 struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
 					  int *ent_cpu, u64 *ent_ts);
 void default_wait_pipe(struct trace_iterator *iter);
 void poll_wait_pipe(struct trace_iterator *iter);
 void ftrace(struct trace_array *tr,
 			    struct trace_array_cpu *data,
 			    unsigned long ip,
 			    unsigned long parent_ip,
 			    unsigned long flags, int pc);
 void tracing_sched_switch_trace(struct trace_array *tr,
 				struct task_struct *prev,
 				struct task_struct *next,
 				unsigned long flags, int pc);
 void tracing_sched_wakeup_trace(struct trace_array *tr,
 				struct task_struct *wakee,
 				struct task_struct *cur,
 				unsigned long flags, int pc);
 void trace_special(struct trace_array *tr,
 		   struct trace_array_cpu *data,
 		   unsigned long arg1,
 		   unsigned long arg2,
 		   unsigned long arg3, int pc);
 void trace_function(struct trace_array *tr,
 		    unsigned long ip,
 		    unsigned long parent_ip,
 		    unsigned long flags, int pc);
 void trace_graph_return(struct ftrace_graph_ret *trace);
 int trace_graph_entry(struct ftrace_graph_ent *trace);
 void set_graph_array(struct trace_array *tr);
 void tracing_start_cmdline_record(void);
 void tracing_stop_cmdline_record(void);
 void tracing_sched_switch_assign_trace(struct trace_array *tr);
 void tracing_stop_sched_switch_record(void);
 void tracing_start_sched_switch_record(void);
 int register_tracer(struct tracer *type);
 void unregister_tracer(struct tracer *type);
 int is_tracing_stopped(void);
 extern int process_new_ksym_entry(char *ksymname, int op, unsigned long addr);
 extern unsigned long nsecs_to_usecs(unsigned long nsecs);
+extern unsigned long tracing_thresh;
 #ifdef CONFIG_TRACER_MAX_TRACE
 extern unsigned long tracing_max_latency;
-extern unsigned long tracing_thresh;
 void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
 void update_max_tr_single(struct trace_array *tr,
 			  struct task_struct *tsk, int cpu);
 #endif /* CONFIG_TRACER_MAX_TRACE */
 #ifdef CONFIG_STACKTRACE
 void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
 			int skip, int pc);
 void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
 			    int pc);
 void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
 		   int pc);
 #else
 static inline void ftrace_trace_stack(struct trace_array *tr,
 				      unsigned long flags, int skip, int pc)
 {
 }
 static inline void ftrace_trace_userstack(struct trace_array *tr,
 					  unsigned long flags, int pc)
 {
 }
 static inline void __trace_stack(struct trace_array *tr, unsigned long flags,
 				 int skip, int pc)
 {
 }
 #endif /* CONFIG_STACKTRACE */
 extern cycle_t ftrace_now(int cpu);
 extern void trace_find_cmdline(int pid, char comm[]);
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern unsigned long ftrace_update_tot_cnt;
 #define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
 extern int DYN_FTRACE_TEST_NAME(void);
 #endif
 extern int ring_buffer_expanded;
 extern bool tracing_selftest_disabled;
 DECLARE_PER_CPU(int, ftrace_cpu_disabled);
 #ifdef CONFIG_FTRACE_STARTUP_TEST
 extern int trace_selftest_startup_function(struct tracer *trace,
 					   struct trace_array *tr);
 extern int trace_selftest_startup_function_graph(struct tracer *trace,
 						 struct trace_array *tr);
 extern int trace_selftest_startup_irqsoff(struct tracer *trace,
 					  struct trace_array *tr);
 extern int trace_selftest_startup_preemptoff(struct tracer *trace,
 					     struct trace_array *tr);
 extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
 						 struct trace_array *tr);
 extern int trace_selftest_startup_wakeup(struct tracer *trace,
 					 struct trace_array *tr);
 extern int trace_selftest_startup_nop(struct tracer *trace,
 					 struct trace_array *tr);
 extern int trace_selftest_startup_sched_switch(struct tracer *trace,
 					       struct trace_array *tr);
 extern int trace_selftest_startup_sysprof(struct tracer *trace,
 					       struct trace_array *tr);
 extern int trace_selftest_startup_branch(struct tracer *trace,
 					 struct trace_array *tr);
 extern int trace_selftest_startup_hw_branches(struct tracer *trace,
 					      struct trace_array *tr);
 extern int trace_selftest_startup_ksym(struct tracer *trace,
 					 struct trace_array *tr);
 #endif /* CONFIG_FTRACE_STARTUP_TEST */
 extern void *head_page(struct trace_array_cpu *data);
 extern unsigned long long ns2usecs(cycle_t nsec);
 extern int
 trace_vbprintk(unsigned long ip, const char *fmt, va_list args);
 extern int
 trace_vprintk(unsigned long ip, const char *fmt, va_list args);
 extern int
 trace_array_vprintk(struct trace_array *tr,
 		    unsigned long ip, const char *fmt, va_list args);
 int trace_array_printk(struct trace_array *tr,
 		       unsigned long ip, const char *fmt, ...);
 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);
 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 */
 #define FTRACE_GRAPH_MAX_FUNCS		32
 extern int ftrace_graph_filter_enabled;
 extern int ftrace_graph_count;
 extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
 static inline int ftrace_graph_addr(unsigned long addr)
 {
 	int i;
 	if (!ftrace_graph_filter_enabled)
 		return 1;
 	for (i = 0; i < ftrace_graph_count; i++) {
 		if (addr == ftrace_graph_funcs[i])
 			return 1;
 	}
 	return 0;
 }
 #else
 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)
 {
 	return TRACE_TYPE_UNHANDLED;
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 extern struct list_head ftrace_pids;
 #ifdef CONFIG_FUNCTION_TRACER
 static inline int ftrace_trace_task(struct task_struct *task)
 {
 	if (list_empty(&ftrace_pids))
 		return 1;
 	return test_tsk_trace_trace(task);
 }
 #else
 static inline int ftrace_trace_task(struct task_struct *task)
 {
 	return 1;
 }
 #endif
 /*
  * struct trace_parser - servers for reading the user input separated by spaces
  * @cont: set if the input is not complete - no final space char was found
  * @buffer: holds the parsed user input
  * @idx: user input lenght
  * @size: buffer size
  */
 struct trace_parser {
 	bool		cont;
 	char		*buffer;
 	unsigned	idx;
 	unsigned	size;
 };
 static inline bool trace_parser_loaded(struct trace_parser *parser)
 {
 	return (parser->idx != 0);
 }
 static inline bool trace_parser_cont(struct trace_parser *parser)
 {
 	return parser->cont;
 }
 static inline void trace_parser_clear(struct trace_parser *parser)
 {
 	parser->cont = false;
 	parser->idx = 0;
 }
 extern int trace_parser_get_init(struct trace_parser *parser, int size);
 extern void trace_parser_put(struct trace_parser *parser);
 extern int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 	size_t cnt, loff_t *ppos);
 /*
  * trace_iterator_flags is an enumeration that defines bit
  * positions into trace_flags that controls the output.
  *
  * NOTE: These bits must match the trace_options array in
  *       trace.c.
  */
 enum trace_iterator_flags {
 	TRACE_ITER_PRINT_PARENT		= 0x01,
 	TRACE_ITER_SYM_OFFSET		= 0x02,
 	TRACE_ITER_SYM_ADDR		= 0x04,
 	TRACE_ITER_VERBOSE		= 0x08,
 	TRACE_ITER_RAW			= 0x10,
 	TRACE_ITER_HEX			= 0x20,
 	TRACE_ITER_BIN			= 0x40,
 	TRACE_ITER_BLOCK		= 0x80,
 	TRACE_ITER_STACKTRACE		= 0x100,
 	TRACE_ITER_PRINTK		= 0x200,
 	TRACE_ITER_PREEMPTONLY		= 0x400,
 	TRACE_ITER_BRANCH		= 0x800,
 	TRACE_ITER_ANNOTATE		= 0x1000,
 	TRACE_ITER_USERSTACKTRACE       = 0x2000,
 	TRACE_ITER_SYM_USEROBJ          = 0x4000,
 	TRACE_ITER_PRINTK_MSGONLY	= 0x8000,
 	TRACE_ITER_CONTEXT_INFO		= 0x10000, /* Print pid/cpu/time */
 	TRACE_ITER_LATENCY_FMT		= 0x20000,
 	TRACE_ITER_SLEEP_TIME		= 0x40000,
 	TRACE_ITER_GRAPH_TIME		= 0x80000,
 };
 /*
  * TRACE_ITER_SYM_MASK masks the options in trace_flags that
  * control the output of kernel symbols.
  */
 #define TRACE_ITER_SYM_MASK \
 	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
 extern struct tracer nop_trace;
 /**
  * ftrace_preempt_disable - disable preemption scheduler safe
  *
  * When tracing can happen inside the scheduler, there exists
  * cases that the tracing might happen before the need_resched
  * flag is checked. If this happens and the tracer calls
  * preempt_enable (after a disable), a schedule might take place
  * causing an infinite recursion.
  *
  * To prevent this, we read the need_resched flag before
  * disabling preemption. When we want to enable preemption we
  * check the flag, if it is set, then we call preempt_enable_no_resched.
  * Otherwise, we call preempt_enable.
  *
  * The rational for doing the above is that if need_resched is set
  * and we have yet to reschedule, we are either in an atomic location
  * (where we do not need to check for scheduling) or we are inside
  * the scheduler and do not want to resched.
  */
 static inline int ftrace_preempt_disable(void)
 {
 	int resched;
 	resched = need_resched();
 	preempt_disable_notrace();
 	return resched;
 }
 /**
  * ftrace_preempt_enable - enable preemption scheduler safe
  * @resched: the return value from ftrace_preempt_disable
  *
  * This is a scheduler safe way to enable preemption and not miss
  * any preemption checks. The disabled saved the state of preemption.
  * If resched is set, then we are either inside an atomic or
  * are inside the scheduler (we would have already scheduled
  * otherwise). In this case, we do not want to call normal
  * preempt_enable, but preempt_enable_no_resched instead.
  */
 static inline void ftrace_preempt_enable(int resched)
 {
 	if (resched)
 		preempt_enable_no_resched_notrace();
 	else
 		preempt_enable_notrace();
 }
 #ifdef CONFIG_BRANCH_TRACER
 extern int enable_branch_tracing(struct trace_array *tr);
 extern void disable_branch_tracing(void);
 static inline int trace_branch_enable(struct trace_array *tr)
 {
 	if (trace_flags & TRACE_ITER_BRANCH)
 		return enable_branch_tracing(tr);
 	return 0;
 }
 static inline void trace_branch_disable(void)
 {
 	/* due to races, always disable */
 	disable_branch_tracing();
 }
 #else
 static inline int trace_branch_enable(struct trace_array *tr)
 {
 	return 0;
 }
 static inline void trace_branch_disable(void)
 {
 }
 #endif /* CONFIG_BRANCH_TRACER */
 /* set ring buffers to default size if not already done so */
 int tracing_update_buffers(void);
 /* trace event type bit fields, not numeric */
 enum {
 	TRACE_EVENT_TYPE_PRINTF		= 1,
 	TRACE_EVENT_TYPE_RAW		= 2,
 };
 struct ftrace_event_field {
 	struct list_head	link;
 	char			*name;
 	char			*type;
 	int			filter_type;
 	int			offset;
 	int			size;
 	int			is_signed;
 };
 struct event_filter {
 	int			n_preds;
 	struct filter_pred	**preds;
 	char			*filter_string;
 };
 struct event_subsystem {
 	struct list_head	list;
 	const char		*name;
 	struct dentry		*entry;
 	struct event_filter	*filter;
 	int			nr_events;
 };
 struct filter_pred;
 struct regex;
 typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
 				 int val1, int val2);
 typedef int (*regex_match_func)(char *str, struct regex *r, int len);
 enum regex_type {
 	MATCH_FULL = 0,
 	MATCH_FRONT_ONLY,
 	MATCH_MIDDLE_ONLY,
 	MATCH_END_ONLY,
 };
 struct regex {
 	char			pattern[MAX_FILTER_STR_VAL];
 	int			len;
 	int			field_len;
 	regex_match_func	match;
 };
 struct filter_pred {
 	filter_pred_fn_t 	fn;
 	u64 			val;
 	struct regex		regex;
 	char 			*field_name;
 	int 			offset;
 	int 			not;
 	int 			op;
 	int 			pop_n;
 };
 extern enum regex_type
 filter_parse_regex(char *buff, int len, char **search, int *not);
 extern void print_event_filter(struct ftrace_event_call *call,
 			       struct trace_seq *s);
 extern int apply_event_filter(struct ftrace_event_call *call,
 			      char *filter_string);
 extern int apply_subsystem_event_filter(struct event_subsystem *system,
 					char *filter_string);
 extern void print_subsystem_event_filter(struct event_subsystem *system,
 					 struct trace_seq *s);
 extern int filter_assign_type(const char *type);
 static inline int
 filter_check_discard(struct ftrace_event_call *call, void *rec,
 		     struct ring_buffer *buffer,
 		     struct ring_buffer_event *event)
 {
 	if (unlikely(call->filter_active) &&
 	    !filter_match_preds(call->filter, rec)) {
 		ring_buffer_discard_commit(buffer, event);
 		return 1;
 	}
 	return 0;
 }
 extern struct mutex event_mutex;
 extern struct list_head ftrace_events;
 extern const char *__start___trace_bprintk_fmt[];
 extern const char *__stop___trace_bprintk_fmt[];
 #undef FTRACE_ENTRY
 #define FTRACE_ENTRY(call, struct_name, id, tstruct, print)		\
 	extern struct ftrace_event_call					\
 	__attribute__((__aligned__(4))) event_##call;
 #undef FTRACE_ENTRY_DUP
 #define FTRACE_ENTRY_DUP(call, struct_name, id, tstruct, print)		\
 	FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
 #include "trace_entries.h"
 #endif /* _LINUX_KERNEL_TRACE_H */

kernel/trace/trace_functions_graph.c

Diff comments View file @ 915a0b5

 /*
  *
  * Function graph tracer.
  * Copyright (c) 2008-2009 Frederic Weisbecker <fweisbec@gmail.com>
  * Mostly borrowed from function tracer which
  * is Copyright (c) Steven Rostedt <srostedt@redhat.com>
  *
  */
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/fs.h>
 #include "trace.h"
 #include "trace_output.h"
 struct fgraph_cpu_data {
 	pid_t		last_pid;
 	int		depth;
 	int		ignore;
 	unsigned long	enter_funcs[FTRACE_RETFUNC_DEPTH];
 };
 struct fgraph_data {
 	struct fgraph_cpu_data		*cpu_data;
 	/* Place to preserve last processed entry. */
 	struct ftrace_graph_ent_entry	ent;
 	struct ftrace_graph_ret_entry	ret;
 	int				failed;
 	int				cpu;
 };
 #define TRACE_GRAPH_INDENT	2
 /* Flag options */
 #define TRACE_GRAPH_PRINT_OVERRUN	0x1
 #define TRACE_GRAPH_PRINT_CPU		0x2
 #define TRACE_GRAPH_PRINT_OVERHEAD	0x4
 #define TRACE_GRAPH_PRINT_PROC		0x8
 #define TRACE_GRAPH_PRINT_DURATION	0x10
 #define TRACE_GRAPH_PRINT_ABS_TIME	0X20
 static struct tracer_opt trace_opts[] = {
 	/* Display overruns? (for self-debug purpose) */
 	{ TRACER_OPT(funcgraph-overrun, TRACE_GRAPH_PRINT_OVERRUN) },
 	/* Display CPU ? */
 	{ TRACER_OPT(funcgraph-cpu, TRACE_GRAPH_PRINT_CPU) },
 	/* Display Overhead ? */
 	{ TRACER_OPT(funcgraph-overhead, TRACE_GRAPH_PRINT_OVERHEAD) },
 	/* Display proc name/pid */
 	{ TRACER_OPT(funcgraph-proc, TRACE_GRAPH_PRINT_PROC) },
 	/* Display duration of execution */
 	{ TRACER_OPT(funcgraph-duration, TRACE_GRAPH_PRINT_DURATION) },
 	/* Display absolute time of an entry */
 	{ TRACER_OPT(funcgraph-abstime, TRACE_GRAPH_PRINT_ABS_TIME) },
 	{ } /* Empty entry */
 };
 static struct tracer_flags tracer_flags = {
 	/* Don't display overruns and proc by default */
 	.val = TRACE_GRAPH_PRINT_CPU | TRACE_GRAPH_PRINT_OVERHEAD |
 	       TRACE_GRAPH_PRINT_DURATION,
 	.opts = trace_opts
 };
 static struct trace_array *graph_array;
 /* Add a function return address to the trace stack on thread info.*/
 int
 ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
 			 unsigned long frame_pointer)
 {
 	unsigned long long calltime;
 	int index;
 	if (!current->ret_stack)
 		return -EBUSY;
 	/*
 	 * We must make sure the ret_stack is tested before we read
 	 * anything else.
 	 */
 	smp_rmb();
 	/* The return trace stack is full */
 	if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
 		atomic_inc(&current->trace_overrun);
 		return -EBUSY;
 	}
 	calltime = trace_clock_local();
 	index = ++current->curr_ret_stack;
 	barrier();
 	current->ret_stack[index].ret = ret;
 	current->ret_stack[index].func = func;
 	current->ret_stack[index].calltime = calltime;
 	current->ret_stack[index].subtime = 0;
 	current->ret_stack[index].fp = frame_pointer;
 	*depth = index;
 	return 0;
 }
 /* Retrieve a function return address to the trace stack on thread info.*/
 static void
 ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
 			unsigned long frame_pointer)
 {
 	int index;
 	index = current->curr_ret_stack;
 	if (unlikely(index < 0)) {
 		ftrace_graph_stop();
 		WARN_ON(1);
 		/* Might as well panic, otherwise we have no where to go */
 		*ret = (unsigned long)panic;
 		return;
 	}
 #ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
 	/*
 	 * The arch may choose to record the frame pointer used
 	 * and check it here to make sure that it is what we expect it
 	 * to be. If gcc does not set the place holder of the return
 	 * address in the frame pointer, and does a copy instead, then
 	 * the function graph trace will fail. This test detects this
 	 * case.
 	 *
 	 * Currently, x86_32 with optimize for size (-Os) makes the latest
 	 * gcc do the above.
 	 */
 	if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
 		ftrace_graph_stop();
 		WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
 		     "  from func %ps return to %lx\n",
 		     current->ret_stack[index].fp,
 		     frame_pointer,
 		     (void *)current->ret_stack[index].func,
 		     current->ret_stack[index].ret);
 		*ret = (unsigned long)panic;
 		return;
 	}
 #endif
 	*ret = current->ret_stack[index].ret;
 	trace->func = current->ret_stack[index].func;
 	trace->calltime = current->ret_stack[index].calltime;
 	trace->overrun = atomic_read(&current->trace_overrun);
 	trace->depth = index;
 }
 /*
  * Send the trace to the ring-buffer.
  * @return the original return address.
  */
 unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
 {
 	struct ftrace_graph_ret trace;
 	unsigned long ret;
 	ftrace_pop_return_trace(&trace, &ret, frame_pointer);
 	trace.rettime = trace_clock_local();
 	ftrace_graph_return(&trace);
 	barrier();
 	current->curr_ret_stack--;
 	if (unlikely(!ret)) {
 		ftrace_graph_stop();
 		WARN_ON(1);
 		/* Might as well panic. What else to do? */
 		ret = (unsigned long)panic;
 	}
 	return ret;
 }
 static int __trace_graph_entry(struct trace_array *tr,
 				struct ftrace_graph_ent *trace,
 				unsigned long flags,
 				int pc)
 {
 	struct ftrace_event_call *call = &event_funcgraph_entry;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer = tr->buffer;
 	struct ftrace_graph_ent_entry *entry;
 	if (unlikely(__this_cpu_read(per_cpu_var(ftrace_cpu_disabled))))
 		return 0;
 	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_ENT,
 					  sizeof(*entry), flags, pc);
 	if (!event)
 		return 0;
 	entry	= ring_buffer_event_data(event);
 	entry->graph_ent			= *trace;
 	if (!filter_current_check_discard(buffer, call, entry, event))
 		ring_buffer_unlock_commit(buffer, event);
 	return 1;
 }
 int trace_graph_entry(struct ftrace_graph_ent *trace)
 {
 	struct trace_array *tr = graph_array;
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	long disabled;
 	int ret;
 	int cpu;
 	int pc;
 	if (!ftrace_trace_task(current))
 		return 0;
 	/* trace it when it is-nested-in or is a function enabled. */
 	if (!(trace->depth || ftrace_graph_addr(trace->func)))
 		return 0;
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 	disabled = atomic_inc_return(&data->disabled);
 	if (likely(disabled == 1)) {
 		pc = preempt_count();
 		ret = __trace_graph_entry(tr, trace, flags, pc);
 	} else {
 		ret = 0;
 	}
 	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 	return ret;
 }
+int trace_graph_thresh_entry(struct ftrace_graph_ent *trace)
+{
+	if (tracing_thresh)
+		return 1;
+	else
+		return trace_graph_entry(trace);
+}
 static void __trace_graph_return(struct trace_array *tr,
 				struct ftrace_graph_ret *trace,
 				unsigned long flags,
 				int pc)
 {
 	struct ftrace_event_call *call = &event_funcgraph_exit;
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer = tr->buffer;
 	struct ftrace_graph_ret_entry *entry;
 	if (unlikely(__this_cpu_read(per_cpu_var(ftrace_cpu_disabled))))
 		return;
 	event = trace_buffer_lock_reserve(buffer, TRACE_GRAPH_RET,
 					  sizeof(*entry), flags, pc);
 	if (!event)
 		return;
 	entry	= ring_buffer_event_data(event);
 	entry->ret				= *trace;
 	if (!filter_current_check_discard(buffer, call, entry, event))
 		ring_buffer_unlock_commit(buffer, event);
 }
 void trace_graph_return(struct ftrace_graph_ret *trace)
 {
 	struct trace_array *tr = graph_array;
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	long disabled;
 	int cpu;
 	int pc;
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = tr->data[cpu];
 	disabled = atomic_inc_return(&data->disabled);
 	if (likely(disabled == 1)) {
 		pc = preempt_count();
 		__trace_graph_return(tr, trace, flags, pc);
 	}
 	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 }
 void set_graph_array(struct trace_array *tr)
 {
 	graph_array = tr;
 	/* Make graph_array visible before we start tracing */
 	smp_mb();
 }
+void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
+{
+	if (tracing_thresh &&
+	    (trace->rettime - trace->calltime < tracing_thresh))
+		return;
+	else
+		trace_graph_return(trace);
+}
 static int graph_trace_init(struct trace_array *tr)
 {
 	int ret;
 	set_graph_array(tr);
-	ret = register_ftrace_graph(&trace_graph_return,
+	if (tracing_thresh)
-				    &trace_graph_entry);
+		ret = register_ftrace_graph(&trace_graph_thresh_return,
+					    &trace_graph_thresh_entry);
+	else
+		ret = register_ftrace_graph(&trace_graph_return,
+					    &trace_graph_entry);
 	if (ret)
 		return ret;
 	tracing_start_cmdline_record();
 	return 0;
 }
 static void graph_trace_reset(struct trace_array *tr)
 {
 	tracing_stop_cmdline_record();
 	unregister_ftrace_graph();
 }
 static int max_bytes_for_cpu;
 static enum print_line_t
 print_graph_cpu(struct trace_seq *s, int cpu)
 {
 	int ret;
 	/*
 	 * Start with a space character - to make it stand out
 	 * to the right a bit when trace output is pasted into
 	 * email:
 	 */
 	ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 #define TRACE_GRAPH_PROCINFO_LENGTH	14
 static enum print_line_t
 print_graph_proc(struct trace_seq *s, pid_t pid)
 {
 	char comm[TASK_COMM_LEN];
 	/* sign + log10(MAX_INT) + '\0' */
 	char pid_str[11];
 	int spaces = 0;
 	int ret;
 	int len;
 	int i;
 	trace_find_cmdline(pid, comm);
 	comm[7] = '\0';
 	sprintf(pid_str, "%d", pid);
 	/* 1 stands for the "-" character */
 	len = strlen(comm) + strlen(pid_str) + 1;
 	if (len < TRACE_GRAPH_PROCINFO_LENGTH)
 		spaces = TRACE_GRAPH_PROCINFO_LENGTH - len;
 	/* First spaces to align center */
 	for (i = 0; i < spaces / 2; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	ret = trace_seq_printf(s, "%s-%s", comm, pid_str);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Last spaces to align center */
 	for (i = 0; i < spaces - (spaces / 2); i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	return TRACE_TYPE_HANDLED;
 }
 static enum print_line_t
 print_graph_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
 {
 	if (!trace_seq_putc(s, ' '))
 		return 0;
 	return trace_print_lat_fmt(s, entry);
 }
 /* If the pid changed since the last trace, output this event */
 static enum print_line_t
 verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 {
 	pid_t prev_pid;
 	pid_t *last_pid;
 	int ret;
 	if (!data)
 		return TRACE_TYPE_HANDLED;
 	last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 	if (*last_pid == pid)
 		return TRACE_TYPE_HANDLED;
 	prev_pid = *last_pid;
 	*last_pid = pid;
 	if (prev_pid == -1)
 		return TRACE_TYPE_HANDLED;
 /*
  * Context-switch trace line:
  ------------------------------------------
  | 1)  migration/0--1  =>  sshd-1755
  ------------------------------------------
  */
 	ret = trace_seq_printf(s,
 		" ------------------------------------------\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	ret = print_graph_cpu(s, cpu);
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 	ret = print_graph_proc(s, prev_pid);
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 	ret = trace_seq_printf(s, " => ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	ret = print_graph_proc(s, pid);
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 	ret = trace_seq_printf(s,
 		"\n ------------------------------------------\n\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 static struct ftrace_graph_ret_entry *
 get_return_for_leaf(struct trace_iterator *iter,
 		struct ftrace_graph_ent_entry *curr)
 {
 	struct fgraph_data *data = iter->private;
 	struct ring_buffer_iter *ring_iter = NULL;
 	struct ring_buffer_event *event;
 	struct ftrace_graph_ret_entry *next;
 	/*
 	 * If the previous output failed to write to the seq buffer,
 	 * then we just reuse the data from before.
 	 */
 	if (data && data->failed) {
 		curr = &data->ent;
 		next = &data->ret;
 	} else {
 		ring_iter = iter->buffer_iter[iter->cpu];
 		/* First peek to compare current entry and the next one */
 		if (ring_iter)
 			event = ring_buffer_iter_peek(ring_iter, NULL);
 		else {
 			/*
 			 * We need to consume the current entry to see
 			 * the next one.
 			 */
 			ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
 			event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
 						 NULL);
 		}
 		if (!event)
 			return NULL;
 		next = ring_buffer_event_data(event);
 		if (data) {
 			/*
 			 * Save current and next entries for later reference
 			 * if the output fails.
 			 */
 			data->ent = *curr;
 			data->ret = *next;
 		}
 	}
 	if (next->ent.type != TRACE_GRAPH_RET)
 		return NULL;
 	if (curr->ent.pid != next->ent.pid ||
 			curr->graph_ent.func != next->ret.func)
 		return NULL;
 	/* this is a leaf, now advance the iterator */
 	if (ring_iter)
 		ring_buffer_read(ring_iter, NULL);
 	return next;
 }
 /* Signal a overhead of time execution to the output */
 static int
 print_graph_overhead(unsigned long long duration, struct trace_seq *s)
 {
 	/* If duration disappear, we don't need anything */
 	if (!(tracer_flags.val & TRACE_GRAPH_PRINT_DURATION))
 		return 1;
 	/* Non nested entry or return */
 	if (duration == -1)
 		return trace_seq_printf(s, "  ");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
 		/* Duration exceeded 100 msecs */
 		if (duration > 100000ULL)
 			return trace_seq_printf(s, "! ");
 		/* Duration exceeded 10 msecs */
 		if (duration > 10000ULL)
 			return trace_seq_printf(s, "+ ");
 	}
 	return trace_seq_printf(s, "  ");
 }
 static int print_graph_abs_time(u64 t, struct trace_seq *s)
 {
 	unsigned long usecs_rem;
 	usecs_rem = do_div(t, NSEC_PER_SEC);
 	usecs_rem /= 1000;
 	return trace_seq_printf(s, "%5lu.%06lu |  ",
 			(unsigned long)t, usecs_rem);
 }
 static enum print_line_t
 print_graph_irq(struct trace_iterator *iter, unsigned long addr,
 		enum trace_type type, int cpu, pid_t pid)
 {
 	int ret;
 	struct trace_seq *s = &iter->seq;
 	if (addr < (unsigned long)__irqentry_text_start ||
 		addr >= (unsigned long)__irqentry_text_end)
 		return TRACE_TYPE_UNHANDLED;
 	/* Absolute time */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 		ret = print_graph_abs_time(iter->ts, s);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Cpu */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 		ret = print_graph_cpu(s, cpu);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Proc */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 		ret = print_graph_proc(s, pid);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 		ret = trace_seq_printf(s, " | ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* No overhead */
 	ret = print_graph_overhead(-1, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	if (type == TRACE_GRAPH_ENT)
 		ret = trace_seq_printf(s, "==========>");
 	else
 		ret = trace_seq_printf(s, "<==========");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Don't close the duration column if haven't one */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 		trace_seq_printf(s, " |");
 	ret = trace_seq_printf(s, "\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 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' */
 	char msecs_str[21];
 	char nsecs_str[5];
 	int ret, len;
 	int i;
 	sprintf(msecs_str, "%lu", (unsigned long) duration);
 	/* Print msecs */
 	ret = trace_seq_printf(s, "%s", msecs_str);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	len = strlen(msecs_str);
 	/* Print nsecs (we don't want to exceed 7 numbers) */
 	if (len < 7) {
 		snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
 		ret = trace_seq_printf(s, ".%s", nsecs_str);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 		len += strlen(nsecs_str);
 	}
 	ret = trace_seq_printf(s, " us ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Print remaining spaces to fit the row's width */
 	for (i = len; i < 7; i++) {
 		ret = trace_seq_printf(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;
 }
 /* Case of a leaf function on its call entry */
 static enum print_line_t
 print_graph_entry_leaf(struct trace_iterator *iter,
 		struct ftrace_graph_ent_entry *entry,
 		struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 {
 	struct fgraph_data *data = iter->private;
 	struct ftrace_graph_ret *graph_ret;
 	struct ftrace_graph_ent *call;
 	unsigned long long duration;
 	int ret;
 	int i;
 	graph_ret = &ret_entry->ret;
 	call = &entry->graph_ent;
 	duration = graph_ret->rettime - graph_ret->calltime;
 	if (data) {
 		struct fgraph_cpu_data *cpu_data;
 		int cpu = iter->cpu;
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 		/*
 		 * Comments display at + 1 to depth. Since
 		 * this is a leaf function, keep the comments
 		 * equal to this depth.
 		 */
 		cpu_data->depth = call->depth - 1;
 		/* No need to keep this function around for this depth */
 		if (call->depth < FTRACE_RETFUNC_DEPTH)
 			cpu_data->enter_funcs[call->depth] = 0;
 	}
 	/* Overhead */
 	ret = print_graph_overhead(duration, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Duration */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 		ret = print_graph_duration(duration, s);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Function */
 	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	ret = trace_seq_printf(s, "%ps();\n", (void *)call->func);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 static enum print_line_t
 print_graph_entry_nested(struct trace_iterator *iter,
 			 struct ftrace_graph_ent_entry *entry,
 			 struct trace_seq *s, int cpu)
 {
 	struct ftrace_graph_ent *call = &entry->graph_ent;
 	struct fgraph_data *data = iter->private;
 	int ret;
 	int i;
 	if (data) {
 		struct fgraph_cpu_data *cpu_data;
 		int cpu = iter->cpu;
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 		cpu_data->depth = call->depth;
 		/* Save this function pointer to see if the exit matches */
 		if (call->depth < FTRACE_RETFUNC_DEPTH)
 			cpu_data->enter_funcs[call->depth] = call->func;
 	}
 	/* No overhead */
 	ret = print_graph_overhead(-1, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* No time */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 		ret = trace_seq_printf(s, "            |  ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Function */
 	for (i = 0; i < call->depth * TRACE_GRAPH_INDENT; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	ret = trace_seq_printf(s, "%ps() {\n", (void *)call->func);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/*
 	 * we already consumed the current entry to check the next one
 	 * and see if this is a leaf.
 	 */
 	return TRACE_TYPE_NO_CONSUME;
 }
 static enum print_line_t
 print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
 		     int type, unsigned long addr)
 {
 	struct fgraph_data *data = iter->private;
 	struct trace_entry *ent = iter->ent;
 	int cpu = iter->cpu;
 	int ret;
 	/* Pid */
 	if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 	if (type) {
 		/* Interrupt */
 		ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Absolute time */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
 		ret = print_graph_abs_time(iter->ts, s);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Cpu */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
 		ret = print_graph_cpu(s, cpu);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Proc */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
 		ret = print_graph_proc(s, ent->pid);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 		ret = trace_seq_printf(s, " | ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Latency format */
 	if (trace_flags & TRACE_ITER_LATENCY_FMT) {
 		ret = print_graph_lat_fmt(s, ent);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	return 0;
 }
 static enum print_line_t
 print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
 			struct trace_iterator *iter)
 {
 	struct fgraph_data *data = iter->private;
 	struct ftrace_graph_ent *call = &field->graph_ent;
 	struct ftrace_graph_ret_entry *leaf_ret;
 	static enum print_line_t ret;
 	int cpu = iter->cpu;
 	if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
 		return TRACE_TYPE_PARTIAL_LINE;
 	leaf_ret = get_return_for_leaf(iter, field);
 	if (leaf_ret)
 		ret = print_graph_entry_leaf(iter, field, leaf_ret, s);
 	else
 		ret = print_graph_entry_nested(iter, field, s, cpu);
 	if (data) {
 		/*
 		 * If we failed to write our output, then we need to make
 		 * note of it. Because we already consumed our entry.
 		 */
 		if (s->full) {
 			data->failed = 1;
 			data->cpu = cpu;
 		} else
 			data->failed = 0;
 	}
 	return ret;
 }
 static enum print_line_t
 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 		   struct trace_entry *ent, struct trace_iterator *iter)
 {
 	unsigned long long duration = trace->rettime - trace->calltime;
 	struct fgraph_data *data = iter->private;
 	pid_t pid = ent->pid;
 	int cpu = iter->cpu;
 	int func_match = 1;
 	int ret;
 	int i;
 	if (data) {
 		struct fgraph_cpu_data *cpu_data;
 		int cpu = iter->cpu;
 		cpu_data = per_cpu_ptr(data->cpu_data, cpu);
 		/*
 		 * Comments display at + 1 to depth. This is the
 		 * return from a function, we now want the comments
 		 * to display at the same level of the bracket.
 		 */
 		cpu_data->depth = trace->depth - 1;
 		if (trace->depth < FTRACE_RETFUNC_DEPTH) {
 			if (cpu_data->enter_funcs[trace->depth] != trace->func)
 				func_match = 0;
 			cpu_data->enter_funcs[trace->depth] = 0;
 		}
 	}
 	if (print_graph_prologue(iter, s, 0, 0))
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Overhead */
 	ret = print_graph_overhead(duration, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* Duration */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 		ret = print_graph_duration(duration, s);
 		if (ret == TRACE_TYPE_PARTIAL_LINE)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Closing brace */
 	for (i = 0; i < trace->depth * TRACE_GRAPH_INDENT; i++) {
 		ret = trace_seq_printf(s, " ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/*
 	 * If the return function does not have a matching entry,
 	 * then the entry was lost. Instead of just printing
 	 * the '}' and letting the user guess what function this
 	 * belongs to, write out the function name.
 	 */
 	if (func_match) {
 		ret = trace_seq_printf(s, "}\n");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	} else {
-		ret = trace_seq_printf(s, "} (%ps)\n", (void *)trace->func);
+		ret = trace_seq_printf(s, "} /* %ps */\n", (void *)trace->func);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Overrun */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERRUN) {
 		ret = trace_seq_printf(s, " (Overruns: %lu)\n",
 					trace->overrun);
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
 	if (ret == TRACE_TYPE_PARTIAL_LINE)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 static enum print_line_t
 print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
 		    struct trace_iterator *iter)
 {
 	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
 	struct fgraph_data *data = iter->private;
 	struct trace_event *event;
 	int depth = 0;
 	int ret;
 	int i;
 	if (data)
 		depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth;
 	if (print_graph_prologue(iter, s, 0, 0))
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* No overhead */
 	ret = print_graph_overhead(-1, s);
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	/* No time */
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION) {
 		ret = trace_seq_printf(s, "            |  ");
 		if (!ret)
 			return TRACE_TYPE_PARTIAL_LINE;
 	}
 	/* Indentation */
 	if (depth > 0)
 		for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
 			ret = trace_seq_printf(s, " ");
 			if (!ret)
 				return TRACE_TYPE_PARTIAL_LINE;
 		}
 	/* The comment */
 	ret = trace_seq_printf(s, "/* ");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	switch (iter->ent->type) {
 	case TRACE_BPRINT:
 		ret = trace_print_bprintk_msg_only(iter);
 		if (ret != TRACE_TYPE_HANDLED)
 			return ret;
 		break;
 	case TRACE_PRINT:
 		ret = trace_print_printk_msg_only(iter);
 		if (ret != TRACE_TYPE_HANDLED)
 			return ret;
 		break;
 	default:
 		event = ftrace_find_event(ent->type);
 		if (!event)
 			return TRACE_TYPE_UNHANDLED;
 		ret = event->trace(iter, sym_flags);
 		if (ret != TRACE_TYPE_HANDLED)
 			return ret;
 	}
 	/* Strip ending newline */
 	if (s->buffer[s->len - 1] == '\n') {
 		s->buffer[s->len - 1] = '\0';
 		s->len--;
 	}
 	ret = trace_seq_printf(s, " */\n");
 	if (!ret)
 		return TRACE_TYPE_PARTIAL_LINE;
 	return TRACE_TYPE_HANDLED;
 }
 enum print_line_t
 print_graph_function(struct trace_iterator *iter)
 {
 	struct ftrace_graph_ent_entry *field;
 	struct fgraph_data *data = iter->private;
 	struct trace_entry *entry = iter->ent;
 	struct trace_seq *s = &iter->seq;
 	int cpu = iter->cpu;
 	int ret;
 	if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) {
 		per_cpu_ptr(data->cpu_data, cpu)->ignore = 0;
 		return TRACE_TYPE_HANDLED;
 	}
 	/*
 	 * If the last output failed, there's a possibility we need
 	 * to print out the missing entry which would never go out.
 	 */
 	if (data && data->failed) {
 		field = &data->ent;
 		iter->cpu = data->cpu;
 		ret = print_graph_entry(field, s, iter);
 		if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) {
 			per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1;
 			ret = TRACE_TYPE_NO_CONSUME;
 		}
 		iter->cpu = cpu;
 		return ret;
 	}
 	switch (entry->type) {
 	case TRACE_GRAPH_ENT: {
 		/*
 		 * print_graph_entry() may consume the current event,
 		 * thus @field may become invalid, so we need to save it.
 		 * sizeof(struct ftrace_graph_ent_entry) is very small,
 		 * it can be safely saved at the stack.
 		 */
 		struct ftrace_graph_ent_entry saved;
 		trace_assign_type(field, entry);
 		saved = *field;
 		return print_graph_entry(&saved, s, iter);
 	}
 	case TRACE_GRAPH_RET: {
 		struct ftrace_graph_ret_entry *field;
 		trace_assign_type(field, entry);
 		return print_graph_return(&field->ret, s, entry, iter);
 	}
 	default:
 		return print_graph_comment(s, entry, iter);
 	}
 	return TRACE_TYPE_HANDLED;
 }
 static void print_lat_header(struct seq_file *s)
 {
 	static const char spaces[] = "                "	/* 16 spaces */
 		"    "					/* 4 spaces */
 		"                 ";			/* 17 spaces */
 	int size = 0;
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 		size += 16;
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 		size += 4;
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 		size += 17;
 	seq_printf(s, "#%.*s  _-----=> irqs-off        \n", size, spaces);
 	seq_printf(s, "#%.*s / _----=> need-resched    \n", size, spaces);
 	seq_printf(s, "#%.*s| / _---=> hardirq/softirq \n", size, spaces);
 	seq_printf(s, "#%.*s|| / _--=> preempt-depth   \n", size, spaces);
 	seq_printf(s, "#%.*s||| / _-=> lock-depth      \n", size, spaces);
 	seq_printf(s, "#%.*s|||| /                     \n", size, spaces);
 }
 static void print_graph_headers(struct seq_file *s)
 {
 	int lat = trace_flags & TRACE_ITER_LATENCY_FMT;
 	if (lat)
 		print_lat_header(s);
 	/* 1st line */
 	seq_printf(s, "#");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 		seq_printf(s, "     TIME       ");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 		seq_printf(s, " CPU");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 		seq_printf(s, "  TASK/PID       ");
 	if (lat)
 		seq_printf(s, "|||||");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 		seq_printf(s, "  DURATION   ");
 	seq_printf(s, "               FUNCTION CALLS\n");
 	/* 2nd line */
 	seq_printf(s, "#");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME)
 		seq_printf(s, "      |         ");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU)
 		seq_printf(s, " |  ");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC)
 		seq_printf(s, "   |    |        ");
 	if (lat)
 		seq_printf(s, "|||||");
 	if (tracer_flags.val & TRACE_GRAPH_PRINT_DURATION)
 		seq_printf(s, "   |   |      ");
 	seq_printf(s, "               |   |   |   |\n");
 }
 static void graph_trace_open(struct trace_iterator *iter)
 {
 	/* pid and depth on the last trace processed */
 	struct fgraph_data *data;
 	int cpu;
 	iter->private = NULL;
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		goto out_err;
 	data->cpu_data = alloc_percpu(struct fgraph_cpu_data);
 	if (!data->cpu_data)
 		goto out_err_free;
 	for_each_possible_cpu(cpu) {
 		pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid);
 		int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
 		int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore);
 		*pid = -1;
 		*depth = 0;
 		*ignore = 0;
 	}
 	iter->private = data;
 	return;
  out_err_free:
 	kfree(data);
  out_err:
 	pr_warning("function graph tracer: not enough memory\n");
 }
 static void graph_trace_close(struct trace_iterator *iter)
 {
 	struct fgraph_data *data = iter->private;
 	if (data) {
 		free_percpu(data->cpu_data);
 		kfree(data);
 	}
 }
 static struct tracer graph_trace __read_mostly = {
 	.name		= "function_graph",
 	.open		= graph_trace_open,
 	.pipe_open	= graph_trace_open,
 	.close		= graph_trace_close,
 	.pipe_close	= graph_trace_close,
 	.wait_pipe	= poll_wait_pipe,
 	.init		= graph_trace_init,
 	.reset		= graph_trace_reset,
 	.print_line	= print_graph_function,
 	.print_header	= print_graph_headers,
 	.flags		= &tracer_flags,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest	= trace_selftest_startup_function_graph,
 #endif
 };
 static __init int init_graph_trace(void)
 {
 	max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
 	return register_tracer(&graph_trace);
 }
 device_initcall(init_graph_trace);