Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

tracing: Use one prologue for the preempt irqs off tracer function tracers

Browse source 
The preempt and irqsoff tracers have 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 if interrupts are enabled or not).

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 19:41:43 -04:00 committed by Steven Rostedt
parent 542181d376
commit 5e6d2b9cfa
1 changed files with 48 additions and 48 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

96
kernel/trace/trace_irqsoff.c
View file

@ -87,14 +87,22 @@ static __cacheline_aligned_in_smp unsigned long max_sequence;
#ifdef CONFIG_FUNCTION_TRACER
/*
* irqsoff uses its own tracer function to keep the overhead down:
* Prologue for the preempt and irqs off function tracers.
*
* Returns 1 if it is OK to continue, and data->disabled is
* incremented.
* 0 if the trace is to be ignored, 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 void
irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
static int func_prolog_dec(struct trace_array *tr,
struct trace_array_cpu **data,
unsigned long *flags)
{
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
@ -106,18 +114,38 @@ irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
*/
cpu = raw_smp_processor_id();
if (likely(!per_cpu(tracing_cpu, cpu)))
return;
return 0;
local_save_flags(flags);
local_save_flags(*flags);
/* slight chance to get a false positive on tracing_cpu */
if (!irqs_disabled_flags(flags))
return;
if (!irqs_disabled_flags(*flags))
return 0;
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
*data = tr->data[cpu];
disabled = atomic_inc_return(&(*data)->disabled);
if (likely(disabled == 1))
trace_function(tr, ip, parent_ip, flags, preempt_count());
return 1;
atomic_dec(&(*data)->disabled);
return 0;
}
/*
* irqsoff uses its own tracer function to keep the overhead down:
*/
static void
irqsoff_tracer_call(unsigned long ip, unsigned long parent_ip)
{
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
if (!func_prolog_dec(tr, &data, &flags))
return;
trace_function(tr, ip, parent_ip, flags, preempt_count());
atomic_dec(&data->disabled);
}
@ -155,30 +183,16 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace)
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int ret;
int cpu;
int pc;
cpu = raw_smp_processor_id();
if (likely(!per_cpu(tracing_cpu, cpu)))
if (!func_prolog_dec(tr, &data, &flags))
return 0;
local_save_flags(flags);
/* slight chance to get a false positive on tracing_cpu */
if (!irqs_disabled_flags(flags))
return 0;
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;
pc = preempt_count();
ret = __trace_graph_entry(tr, trace, flags, pc);
atomic_dec(&data->disabled);
return ret;
}
@ -187,27 +201,13 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace)
struct trace_array *tr = irqsoff_trace;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
cpu = raw_smp_processor_id();
if (likely(!per_cpu(tracing_cpu, cpu)))
if (!func_prolog_dec(tr, &data, &flags))
return;
local_save_flags(flags);
/* slight chance to get a false positive on tracing_cpu */
if (!irqs_disabled_flags(flags))
return;
data = tr->data[cpu];
disabled = atomic_inc_return(&data->disabled);
if (likely(disabled == 1)) {
pc = preempt_count();
__trace_graph_return(tr, trace, flags, pc);
}
pc = preempt_count();
__trace_graph_return(tr, trace, flags, pc);
atomic_dec(&data->disabled);
}