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tracing: Use one prologue for the wakeup tracer function tracers

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The wakeup tracer has three types of function tracers. Normal
function tracer, function graph entry, and function graph return.
Each of these use a complex dance to prevent recursion and whether
to trace the data or not (depending on the wake_task variable).

This patch moves the duplicate code into a single routine, to
prevent future mistakes with modifying duplicate complex code.

Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2010-10-05 16:38:49 -04:00 committed by Steven Rostedt
parent 7495a5beaa
commit 542181d376
1 changed files with 54 additions and 56 deletions
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110
kernel/trace/trace_sched_wakeup.c
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@ -56,6 +56,54 @@ static struct tracer_flags tracer_flags = {
#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH)
#ifdef CONFIG_FUNCTION_TRACER
/*
* Prologue for the wakeup function tracers.
*
* Returns 1 if it is OK to continue, and preemption
* is disabled and data->disabled is incremented.
* 0 if the trace is to be ignored, and preemption
* is not disabled and data->disabled is
* kept the same.
*
* Note, this function is also used outside this ifdef but
* inside the #ifdef of the function graph tracer below.
* This is OK, since the function graph tracer is
* dependent on the function tracer.
*/
static int
func_prolog_preempt_disable(struct trace_array *tr,
struct trace_array_cpu **data,
int *pc)
{
long disabled;
int cpu;
if (likely(!wakeup_task))
return 0;
*pc = preempt_count();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
if (cpu != wakeup_current_cpu)
goto out_enable;
*data = tr->data[cpu];
disabled = atomic_inc_return(&(*data)->disabled);
if (unlikely(disabled != 1))
goto out;
return 1;
out:
atomic_dec(&(*data)->disabled);
out_enable:
preempt_enable_notrace();
return 0;
}
/*
* wakeup uses its own tracer function to keep the overhead down:
*/
@ -65,34 +113,16 @@ wakeup_tracer_call(unsigned long ip, unsigned long parent_ip)
struct trace_array *tr = wakeup_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
if (likely(!wakeup_task))
if (!func_prolog_preempt_disable(tr, &data, &pc))
return;
pc = preempt_count();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
if (cpu != wakeup_current_cpu)
goto out_enable;
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (unlikely(disabled != 1))
goto out;
local_irq_save(flags);
trace_function(tr, ip, parent_ip, flags, pc);
local_irq_restore(flags);
out:
atomic_dec(&data->disabled);
out_enable:
preempt_enable_notrace();
}
@ -154,32 +184,16 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace)
struct trace_array *tr = wakeup_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu, pc, ret = 0;
int pc, ret = 0;
if (likely(!wakeup_task))
if (!func_prolog_preempt_disable(tr, &data, &pc))
return 0;
pc = preempt_count();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
if (cpu != wakeup_current_cpu)
goto out_enable;
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (unlikely(disabled != 1))
goto out;
local_save_flags(flags);
ret = __trace_graph_entry(tr, trace, flags, pc);
out:
atomic_dec(&data->disabled);
out_enable:
preempt_enable_notrace();
return ret;
}
@ -188,31 +202,15 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace)
struct trace_array *tr = wakeup_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu, pc;
int pc;
if (likely(!wakeup_task))
if (!func_prolog_preempt_disable(tr, &data, &pc))
return;
pc = preempt_count();
preempt_disable_notrace();
cpu = raw_smp_processor_id();
if (cpu != wakeup_current_cpu)
goto out_enable;
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (unlikely(disabled != 1))
goto out;
local_save_flags(flags);
__trace_graph_return(tr, trace, flags, pc);
out:
atomic_dec(&data->disabled);
out_enable:
preempt_enable_notrace();
return;
}