Commit 1fd8f2a3 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar

tracing/function-graph-tracer: handle ftrace_printk entries

Handle the TRACE_PRINT entries from the function grapg tracer
and output them as a C comment just below the function that called
it, as if it was a comment inside this function.

Example with an ftrace_printk inside might_sleep() function:

void __might_sleep(char *file, int line)
{
	static unsigned long prev_jiffy;	/* ratelimiting */

	ftrace_printk("Hi I'm a comment in might_sleep() :-)");

A chunk of a resulting trace:

 0)               |        _reiserfs_free_block() {
 0)               |          reiserfs_read_bitmap_block() {
 0)               |            __bread() {
 0)               |              __getblk() {
 0)               |                __find_get_block() {
 0)   0.698 us    |                  mark_page_accessed();
 0)   2.267 us    |                }
 0)               |                __might_sleep() {
 0)               |                  /* Hi I'm a comment in might_sleep() :-) */
 0)   1.321 us    |                }
 0)   5.872 us    |              }
 0)   7.313 us    |            }
 0)   8.718 us    |          }

And this patch brings two minor fixes:

- The newline after a switch-out task has disappeared
- The "|" sign just before the cpu number on task-switch has been deleted.

 0)   0.616 us    |                pick_next_task_rt();
 0)   1.457 us    |                _spin_trylock();
 0)   0.653 us    |                _spin_unlock();
 0)   0.728 us    |                _spin_trylock();
 0)   0.631 us    |                _spin_unlock();
 0)   0.729 us    |                native_load_sp0();
 0)   0.593 us    |                native_load_tls();
 ------------------------------------------
 0)    cat-2834    =>   migrati-3
 ------------------------------------------

 0)               |    finish_task_switch() {
 0)   0.841 us    |      _spin_unlock_irq();
 0)   0.616 us    |      post_schedule_rt();
 0)   3.882 us    |    }
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b29144c3
......@@ -3335,7 +3335,7 @@ static int mark_printk(const char *fmt, ...)
int ret;
va_list args;
va_start(args, fmt);
ret = trace_vprintk(0, fmt, args);
ret = trace_vprintk(0, -1, fmt, args);
va_end(args);
return ret;
}
......@@ -3564,9 +3564,16 @@ static __init int tracer_init_debugfs(void)
return 0;
}
int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
{
static DEFINE_SPINLOCK(trace_buf_lock);
/*
* Raw Spinlock because a normal spinlock would be traced here
* and append an irrelevant couple spin_lock_irqsave/
* spin_unlock_irqrestore traced by ftrace around this
* TRACE_PRINTK trace.
*/
static raw_spinlock_t trace_buf_lock =
(raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
static char trace_buf[TRACE_BUF_SIZE];
struct ring_buffer_event *event;
......@@ -3587,7 +3594,8 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
if (unlikely(atomic_read(&data->disabled)))
goto out;
spin_lock_irqsave(&trace_buf_lock, flags);
local_irq_save(flags);
__raw_spin_lock(&trace_buf_lock);
len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
len = min(len, TRACE_BUF_SIZE-1);
......@@ -3601,13 +3609,15 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
tracing_generic_entry_update(&entry->ent, flags, pc);
entry->ent.type = TRACE_PRINT;
entry->ip = ip;
entry->depth = depth;
memcpy(&entry->buf, trace_buf, len);
entry->buf[len] = 0;
ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
out_unlock:
spin_unlock_irqrestore(&trace_buf_lock, flags);
__raw_spin_unlock(&trace_buf_lock);
local_irq_restore(flags);
out:
preempt_enable_notrace();
......@@ -3625,7 +3635,13 @@ int __ftrace_printk(unsigned long ip, const char *fmt, ...)
return 0;
va_start(ap, fmt);
ret = trace_vprintk(ip, fmt, ap);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
ret = trace_vprintk(ip, current->curr_ret_stack, fmt, ap);
#else
ret = trace_vprintk(ip, -1, fmt, ap);
#endif
va_end(ap);
return ret;
}
......
......@@ -117,6 +117,7 @@ struct userstack_entry {
struct print_entry {
struct trace_entry ent;
unsigned long ip;
int depth;
char buf[];
};
......@@ -498,7 +499,8 @@ seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
size_t cnt);
extern long ns2usecs(cycle_t nsec);
extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
extern int
trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
extern unsigned long trace_flags;
......
......@@ -173,7 +173,7 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu)
*/
ret = trace_seq_printf(s,
"\n ------------------------------------------\n |");
" ------------------------------------------\n");
if (!ret)
TRACE_TYPE_PARTIAL_LINE;
......@@ -477,6 +477,71 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
return TRACE_TYPE_HANDLED;
}
static enum print_line_t
print_graph_comment(struct print_entry *trace, struct trace_seq *s,
struct trace_entry *ent, struct trace_iterator *iter)
{
int i;
int ret;
/* Pid */
if (verif_pid(s, ent->pid, iter->cpu) == TRACE_TYPE_PARTIAL_LINE)
return TRACE_TYPE_PARTIAL_LINE;
/* Cpu */
if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
ret = print_graph_cpu(s, iter->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;
}
/* No overhead */
if (tracer_flags.val & TRACE_GRAPH_PRINT_OVERHEAD) {
ret = trace_seq_printf(s, " ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
/* No time */
ret = trace_seq_printf(s, " | ");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
/* Indentation */
if (trace->depth > 0)
for (i = 0; i < (trace->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, "/* %s", trace->buf);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
if (ent->flags & TRACE_FLAG_CONT)
trace_seq_print_cont(s, iter);
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)
{
......@@ -495,6 +560,11 @@ print_graph_function(struct trace_iterator *iter)
trace_assign_type(field, entry);
return print_graph_return(&field->ret, s, entry, iter->cpu);
}
case TRACE_PRINT: {
struct print_entry *field;
trace_assign_type(field, entry);
return print_graph_comment(field, s, entry, iter);
}
default:
return TRACE_TYPE_UNHANDLED;
}
......
......@@ -366,5 +366,5 @@ void mmio_trace_mapping(struct mmiotrace_map *map)
int mmio_trace_printk(const char *fmt, va_list args)
{
return trace_vprintk(0, fmt, args);
return trace_vprintk(0, -1, fmt, args);
}
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