Lucas De MarchiFix common misspellings25985ed15 years agoHistory
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/* * 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/slab.h>#include <linux/ctype.h>#include <linux/list.h>#include <linux/hash.h>#include <linux/rcupdate.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; /* * Traverse the ftrace_list, invoking all entries.  The reason that we * can use rcu_dereference_raw() is that elements removed from this list * are simply leaked, so there is no need to interact with a grace-period * mechanism.  The rcu_dereference_raw() calls are needed to handle * concurrent insertions into the ftrace_list. * * Silly Alpha and silly pointer-speculation compiler optimizations! */static void ftrace_list_func(unsigned long ip, unsigned long parent_ip){	struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/ 	while (op != &ftrace_list_end) {		op->func(ip, parent_ip);		op = rcu_dereference_raw(op->next); /*see above*/	};} 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.	 */	rcu_assign_pointer(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_PROFILERstruct ftrace_profile {	struct hlist_node		node;	unsigned long			ip;	unsigned long			counter;#ifdef CONFIG_FUNCTION_GRAPH_TRACER	unsigned long long		time;	unsigned long long		time_squared;#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             s^2\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];	int ret = 0;#ifdef CONFIG_FUNCTION_GRAPH_TRACER	static struct trace_seq s;	unsigned long long avg;	unsigned long long stddev;#endif	mutex_lock(&ftrace_profile_lock); 	/* we raced with function_profile_reset() */	if (unlikely(rec->counter == 0)) {		ret = -EBUSY;		goto out;	} 	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); 	/* Sample standard deviation (s^2) */	if (rec->counter <= 1)		stddev = 0;	else {		stddev = rec->time_squared - rec->counter * avg * avg;		/*		 * Divide only 1000 for ns^2 -> us^2 conversion.		 * trace_print_graph_duration will divide 1000 again.		 */		do_div(stddev, (rec->counter - 1) * 1000);	} 	trace_seq_init(&s);	trace_print_graph_duration(rec->time, &s);	trace_seq_puts(&s, "    ");	trace_print_graph_duration(avg, &s);	trace_seq_puts(&s, "    ");	trace_print_graph_duration(stddev, &s);	trace_print_seq(m, &s);#endif	seq_putc(m, '\n');out:	mutex_unlock(&ftrace_profile_lock); 	return ret;} 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;

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