kernel-ark/kernel/trace/trace_boot.c
Steven Rostedt e77405ad80 tracing: pass around ring buffer instead of tracer
The latency tracers (irqsoff and wakeup) can swap trace buffers
on the fly. If an event is happening and has reserved data on one of
the buffers, and the latency tracer swaps the global buffer with the
max buffer, the result is that the event may commit the data to the
wrong buffer.

This patch changes the API to the trace recording to be recieve the
buffer that was used to reserve a commit. Then this buffer can be passed
in to the commit.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04 18:59:39 -04:00

182 lines
3.9 KiB
C

/*
* ring buffer based initcalls tracer
*
* Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
*
*/
#include <linux/init.h>
#include <linux/debugfs.h>
#include <linux/ftrace.h>
#include <linux/kallsyms.h>
#include <linux/time.h>
#include "trace.h"
#include "trace_output.h"
static struct trace_array *boot_trace;
static bool pre_initcalls_finished;
/* Tells the boot tracer that the pre_smp_initcalls are finished.
* So we are ready .
* It doesn't enable sched events tracing however.
* You have to call enable_boot_trace to do so.
*/
void start_boot_trace(void)
{
pre_initcalls_finished = true;
}
void enable_boot_trace(void)
{
if (boot_trace && pre_initcalls_finished)
tracing_start_sched_switch_record();
}
void disable_boot_trace(void)
{
if (boot_trace && pre_initcalls_finished)
tracing_stop_sched_switch_record();
}
static int boot_trace_init(struct trace_array *tr)
{
boot_trace = tr;
if (!tr)
return 0;
tracing_reset_online_cpus(tr);
tracing_sched_switch_assign_trace(tr);
return 0;
}
static enum print_line_t
initcall_call_print_line(struct trace_iterator *iter)
{
struct trace_entry *entry = iter->ent;
struct trace_seq *s = &iter->seq;
struct trace_boot_call *field;
struct boot_trace_call *call;
u64 ts;
unsigned long nsec_rem;
int ret;
trace_assign_type(field, entry);
call = &field->boot_call;
ts = iter->ts;
nsec_rem = do_div(ts, NSEC_PER_SEC);
ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
(unsigned long)ts, nsec_rem, call->func, call->caller);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
else
return TRACE_TYPE_HANDLED;
}
static enum print_line_t
initcall_ret_print_line(struct trace_iterator *iter)
{
struct trace_entry *entry = iter->ent;
struct trace_seq *s = &iter->seq;
struct trace_boot_ret *field;
struct boot_trace_ret *init_ret;
u64 ts;
unsigned long nsec_rem;
int ret;
trace_assign_type(field, entry);
init_ret = &field->boot_ret;
ts = iter->ts;
nsec_rem = do_div(ts, NSEC_PER_SEC);
ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
"returned %d after %llu msecs\n",
(unsigned long) ts,
nsec_rem,
init_ret->func, init_ret->result, init_ret->duration);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
else
return TRACE_TYPE_HANDLED;
}
static enum print_line_t initcall_print_line(struct trace_iterator *iter)
{
struct trace_entry *entry = iter->ent;
switch (entry->type) {
case TRACE_BOOT_CALL:
return initcall_call_print_line(iter);
case TRACE_BOOT_RET:
return initcall_ret_print_line(iter);
default:
return TRACE_TYPE_UNHANDLED;
}
}
struct tracer boot_tracer __read_mostly =
{
.name = "initcall",
.init = boot_trace_init,
.reset = tracing_reset_online_cpus,
.print_line = initcall_print_line,
};
void trace_boot_call(struct boot_trace_call *bt, initcall_t fn)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct trace_boot_call *entry;
struct trace_array *tr = boot_trace;
if (!tr || !pre_initcalls_finished)
return;
/* Get its name now since this function could
* disappear because it is in the .init section.
*/
sprint_symbol(bt->func, (unsigned long)fn);
preempt_disable();
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_CALL,
sizeof(*entry), 0, 0);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
entry->boot_call = *bt;
trace_buffer_unlock_commit(buffer, event, 0, 0);
out:
preempt_enable();
}
void trace_boot_ret(struct boot_trace_ret *bt, initcall_t fn)
{
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct trace_boot_ret *entry;
struct trace_array *tr = boot_trace;
if (!tr || !pre_initcalls_finished)
return;
sprint_symbol(bt->func, (unsigned long)fn);
preempt_disable();
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BOOT_RET,
sizeof(*entry), 0, 0);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
entry->boot_ret = *bt;
trace_buffer_unlock_commit(buffer, event, 0, 0);
out:
preempt_enable();
}