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ftrace: Allow instances to use function tracing

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Allow instances (sub-buffers) to enable function tracing.
Each instance will have its own function tracing capability.
For now, instances will not have function stack tracing, or will
they be able to pick and choose what functions they can trace.

Picking and choosing their own functions will come later.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Red Hat) 2013-11-07 20:08:58 -05:00 committed by Steven Rostedt
parent 50512ab576
commit f20a580627
2 changed files with 81 additions and 40 deletions
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5
kernel/trace/trace.h
View File

@ -210,6 +210,11 @@ struct trace_array {
struct list_head events;
cpumask_var_t tracing_cpumask; /* only trace on set CPUs */
int ref;
#ifdef CONFIG_FUNCTION_TRACER
struct ftrace_ops *ops;
/* function tracing enabled */
int function_enabled;
#endif
};
enum {

116
kernel/trace/trace_functions.c
View File

@ -13,33 +13,83 @@
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include "trace.h"
/* function tracing enabled */
static int ftrace_function_enabled;
static void tracing_start_function_trace(struct trace_array *tr);
static void tracing_stop_function_trace(struct trace_array *tr);
static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs);
static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs);
static struct ftrace_ops trace_ops;
static struct ftrace_ops trace_stack_ops;
static struct tracer_flags func_flags;
static struct trace_array *func_trace;
/* Our option */
enum {
TRACE_FUNC_OPT_STACK = 0x1,
};
static void tracing_start_function_trace(void);
static void tracing_stop_function_trace(void);
static int allocate_ftrace_ops(struct trace_array *tr)
{
struct ftrace_ops *ops;
ops = kzalloc(sizeof(*ops), GFP_KERNEL);
if (!ops)
return -ENOMEM;
/* Currently only the non stack verision is supported */
ops->func = function_trace_call;
ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
tr->ops = ops;
ops->private = tr;
return 0;
}
static int function_trace_init(struct trace_array *tr)
{
func_trace = tr;
struct ftrace_ops *ops;
int ret;
if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
/* There's only one global tr */
if (!trace_ops.private) {
trace_ops.private = tr;
trace_stack_ops.private = tr;
}
if (func_flags.val & TRACE_FUNC_OPT_STACK)
ops = &trace_stack_ops;
else
ops = &trace_ops;
tr->ops = ops;
} else {
ret = allocate_ftrace_ops(tr);
if (ret)
return ret;
}
tr->trace_buffer.cpu = get_cpu();
put_cpu();
tracing_start_cmdline_record();
tracing_start_function_trace();
tracing_start_function_trace(tr);
return 0;
}
static void function_trace_reset(struct trace_array *tr)
{
tracing_stop_function_trace();
tracing_stop_function_trace(tr);
tracing_stop_cmdline_record();
if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
kfree(tr->ops);
tr->ops = NULL;
}
static void function_trace_start(struct trace_array *tr)
@ -47,25 +97,18 @@ static void function_trace_start(struct trace_array *tr)
tracing_reset_online_cpus(&tr->trace_buffer);
}
/* Our option */
enum {
TRACE_FUNC_OPT_STACK = 0x1,
};
static struct tracer_flags func_flags;
static void
function_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct trace_array *tr = func_trace;
struct trace_array *tr = op->private;
struct trace_array_cpu *data;
unsigned long flags;
int bit;
int cpu;
int pc;
if (unlikely(!ftrace_function_enabled))
if (unlikely(!tr->function_enabled))
return;
pc = preempt_count();
@ -91,14 +134,14 @@ static void
function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
struct ftrace_ops *op, struct pt_regs *pt_regs)
{
struct trace_array *tr = func_trace;
struct trace_array *tr = op->private;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
int cpu;
int pc;
if (unlikely(!ftrace_function_enabled))
if (unlikely(!tr->function_enabled))
return;
/*
@ -128,7 +171,6 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
local_irq_restore(flags);
}
static struct ftrace_ops trace_ops __read_mostly =
{
.func = function_trace_call,
@ -153,26 +195,17 @@ static struct tracer_flags func_flags = {
.opts = func_opts
};
static void tracing_start_function_trace(void)
static void tracing_start_function_trace(struct trace_array *tr)
{
ftrace_function_enabled = 0;
if (func_flags.val & TRACE_FUNC_OPT_STACK)
register_ftrace_function(&trace_stack_ops);
else
register_ftrace_function(&trace_ops);
ftrace_function_enabled = 1;
tr->function_enabled = 0;
register_ftrace_function(tr->ops);
tr->function_enabled = 1;
}
static void tracing_stop_function_trace(void)
static void tracing_stop_function_trace(struct trace_array *tr)
{
ftrace_function_enabled = 0;
if (func_flags.val & TRACE_FUNC_OPT_STACK)
unregister_ftrace_function(&trace_stack_ops);
else
unregister_ftrace_function(&trace_ops);
tr->function_enabled = 0;
unregister_ftrace_function(tr->ops);
}
static int
@ -184,12 +217,14 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
break;
unregister_ftrace_function(tr->ops);
if (set) {
unregister_ftrace_function(&trace_ops);
register_ftrace_function(&trace_stack_ops);
tr->ops = &trace_stack_ops;
register_ftrace_function(tr->ops);
} else {
unregister_ftrace_function(&trace_stack_ops);
register_ftrace_function(&trace_ops);
tr->ops = &trace_ops;
register_ftrace_function(tr->ops);
}
break;
@ -209,6 +244,7 @@ static struct tracer function_trace __tracer_data =
.wait_pipe = poll_wait_pipe,
.flags = &func_flags,
.set_flag = func_set_flag,
.allow_instances = true,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_function,
#endif