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Port ftrace to markers
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Porting ftrace to the marker infrastructure.

Don't need to chain to the wakeup tracer from the sched tracer, because markers
support multiple probes connected.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Mathieu Desnoyers authored and Thomas Gleixner committed May 23, 2008
1 parent 0aa977f commit 5b82a1b
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Showing 5 changed files with 255 additions and 88 deletions.
32 changes: 0 additions & 32 deletions include/linux/sched.h
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Original file line number Diff line number Diff line change
Expand Up @@ -2131,38 +2131,6 @@ __trace_special(void *__tr, void *__data,
}
#endif

#ifdef CONFIG_CONTEXT_SWITCH_TRACER
extern void
ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next);
extern void
ftrace_wake_up_task(void *rq, struct task_struct *wakee,
struct task_struct *curr);
extern void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data);
extern void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
#else
static inline void
ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next)
{
}
static inline void
sched_trace_special(unsigned long p1, unsigned long p2, unsigned long p3)
{
}
static inline void
ftrace_wake_up_task(void *rq, struct task_struct *wakee,
struct task_struct *curr)
{
}
static inline void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data)
{
}
static inline void
ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
{
}
#endif

extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask);
extern long sched_getaffinity(pid_t pid, cpumask_t *mask);

Expand Down
14 changes: 11 additions & 3 deletions kernel/sched.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2500,7 +2500,9 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
success = 1;

out_running:
ftrace_wake_up_task(rq, p, rq->curr);
trace_mark(kernel_sched_wakeup,
"pid %d state %ld ## rq %p task %p rq->curr %p",
p->pid, p->state, rq, p, rq->curr);
check_preempt_curr(rq, p);

p->state = TASK_RUNNING;
Expand Down Expand Up @@ -2631,7 +2633,9 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
p->sched_class->task_new(rq, p);
inc_nr_running(rq);
}
ftrace_wake_up_task(rq, p, rq->curr);
trace_mark(kernel_sched_wakeup_new,
"pid %d state %ld ## rq %p task %p rq->curr %p",
p->pid, p->state, rq, p, rq->curr);
check_preempt_curr(rq, p);
#ifdef CONFIG_SMP
if (p->sched_class->task_wake_up)
Expand Down Expand Up @@ -2804,7 +2808,11 @@ context_switch(struct rq *rq, struct task_struct *prev,
struct mm_struct *mm, *oldmm;

prepare_task_switch(rq, prev, next);
ftrace_ctx_switch(rq, prev, next);
trace_mark(kernel_sched_schedule,
"prev_pid %d next_pid %d prev_state %ld "
"## rq %p prev %p next %p",
prev->pid, next->pid, prev->state,
rq, prev, next);
mm = next->mm;
oldmm = prev->active_mm;
/*
Expand Down
20 changes: 1 addition & 19 deletions kernel/trace/trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -234,25 +234,10 @@ void update_max_tr_single(struct trace_array *tr,

extern cycle_t ftrace_now(int cpu);

#ifdef CONFIG_SCHED_TRACER
extern void
wakeup_sched_switch(struct task_struct *prev, struct task_struct *next);
extern void
wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr);
#else
static inline void
wakeup_sched_switch(struct task_struct *prev, struct task_struct *next)
{
}
static inline void
wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr)
{
}
#endif

#ifdef CONFIG_CONTEXT_SWITCH_TRACER
typedef void
(*tracer_switch_func_t)(void *private,
void *__rq,
struct task_struct *prev,
struct task_struct *next);

Expand All @@ -262,9 +247,6 @@ struct tracer_switch_ops {
struct tracer_switch_ops *next;
};

extern int register_tracer_switch(struct tracer_switch_ops *ops);
extern int unregister_tracer_switch(struct tracer_switch_ops *ops);

#endif /* CONFIG_CONTEXT_SWITCH_TRACER */

#ifdef CONFIG_DYNAMIC_FTRACE
Expand Down
171 changes: 143 additions & 28 deletions kernel/trace/trace_sched_switch.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,14 @@

static struct trace_array *ctx_trace;
static int __read_mostly tracer_enabled;
static atomic_t sched_ref;

static void
ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next)
sched_switch_func(void *private, void *__rq, struct task_struct *prev,
struct task_struct *next)
{
struct trace_array *tr = ctx_trace;
struct trace_array **ptr = private;
struct trace_array *tr = *ptr;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
Expand All @@ -41,10 +44,40 @@ ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next)
local_irq_restore(flags);
}

static notrace void
sched_switch_callback(void *probe_data, void *call_data,
const char *format, va_list *args)
{
struct task_struct *prev;
struct task_struct *next;
struct rq *__rq;

if (!atomic_read(&sched_ref))
return;

/* skip prev_pid %d next_pid %d prev_state %ld */
(void)va_arg(*args, int);
(void)va_arg(*args, int);
(void)va_arg(*args, long);
__rq = va_arg(*args, typeof(__rq));
prev = va_arg(*args, typeof(prev));
next = va_arg(*args, typeof(next));

tracing_record_cmdline(prev);

/*
* If tracer_switch_func only points to the local
* switch func, it still needs the ptr passed to it.
*/
sched_switch_func(probe_data, __rq, prev, next);
}

static void
wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr)
wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct
task_struct *curr)
{
struct trace_array *tr = ctx_trace;
struct trace_array **ptr = private;
struct trace_array *tr = *ptr;
struct trace_array_cpu *data;
unsigned long flags;
long disabled;
Expand All @@ -67,35 +100,29 @@ wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr)
local_irq_restore(flags);
}

void
ftrace_ctx_switch(void *__rq, struct task_struct *prev,
struct task_struct *next)
static notrace void
wake_up_callback(void *probe_data, void *call_data,
const char *format, va_list *args)
{
if (unlikely(atomic_read(&trace_record_cmdline_enabled)))
tracing_record_cmdline(prev);
struct task_struct *curr;
struct task_struct *task;
struct rq *__rq;

/*
* If tracer_switch_func only points to the local
* switch func, it still needs the ptr passed to it.
*/
ctx_switch_func(__rq, prev, next);
if (likely(!tracer_enabled))
return;

/*
* Chain to the wakeup tracer (this is a NOP if disabled):
*/
wakeup_sched_switch(prev, next);
}
/* Skip pid %d state %ld */
(void)va_arg(*args, int);
(void)va_arg(*args, long);
/* now get the meat: "rq %p task %p rq->curr %p" */
__rq = va_arg(*args, typeof(__rq));
task = va_arg(*args, typeof(task));
curr = va_arg(*args, typeof(curr));

void
ftrace_wake_up_task(void *__rq, struct task_struct *wakee,
struct task_struct *curr)
{
wakeup_func(__rq, wakee, curr);
tracing_record_cmdline(task);
tracing_record_cmdline(curr);

/*
* Chain to the wakeup tracer (this is a NOP if disabled):
*/
wakeup_sched_wakeup(wakee, curr);
wakeup_func(probe_data, __rq, task, curr);
}

void
Expand Down Expand Up @@ -132,15 +159,95 @@ static void sched_switch_reset(struct trace_array *tr)
tracing_reset(tr->data[cpu]);
}

static int tracing_sched_register(void)
{
int ret;

ret = marker_probe_register("kernel_sched_wakeup",
"pid %d state %ld ## rq %p task %p rq->curr %p",
wake_up_callback,
&ctx_trace);
if (ret) {
pr_info("wakeup trace: Couldn't add marker"
" probe to kernel_sched_wakeup\n");
return ret;
}

ret = marker_probe_register("kernel_sched_wakeup_new",
"pid %d state %ld ## rq %p task %p rq->curr %p",
wake_up_callback,
&ctx_trace);
if (ret) {
pr_info("wakeup trace: Couldn't add marker"
" probe to kernel_sched_wakeup_new\n");
goto fail_deprobe;
}

ret = marker_probe_register("kernel_sched_schedule",
"prev_pid %d next_pid %d prev_state %ld "
"## rq %p prev %p next %p",
sched_switch_callback,
&ctx_trace);
if (ret) {
pr_info("sched trace: Couldn't add marker"
" probe to kernel_sched_schedule\n");
goto fail_deprobe_wake_new;
}

return ret;
fail_deprobe_wake_new:
marker_probe_unregister("kernel_sched_wakeup_new",
wake_up_callback,
&ctx_trace);
fail_deprobe:
marker_probe_unregister("kernel_sched_wakeup",
wake_up_callback,
&ctx_trace);
return ret;
}

static void tracing_sched_unregister(void)
{
marker_probe_unregister("kernel_sched_schedule",
sched_switch_callback,
&ctx_trace);
marker_probe_unregister("kernel_sched_wakeup_new",
wake_up_callback,
&ctx_trace);
marker_probe_unregister("kernel_sched_wakeup",
wake_up_callback,
&ctx_trace);
}

void tracing_start_sched_switch(void)
{
long ref;

ref = atomic_inc_return(&sched_ref);
if (ref == 1)
tracing_sched_register();
}

void tracing_stop_sched_switch(void)
{
long ref;

ref = atomic_dec_and_test(&sched_ref);
if (ref)
tracing_sched_unregister();
}

static void start_sched_trace(struct trace_array *tr)
{
sched_switch_reset(tr);
atomic_inc(&trace_record_cmdline_enabled);
tracer_enabled = 1;
tracing_start_sched_switch();
}

static void stop_sched_trace(struct trace_array *tr)
{
tracing_stop_sched_switch();
atomic_dec(&trace_record_cmdline_enabled);
tracer_enabled = 0;
}
Expand Down Expand Up @@ -181,6 +288,14 @@ static struct tracer sched_switch_trace __read_mostly =

__init static int init_sched_switch_trace(void)
{
int ret = 0;

if (atomic_read(&sched_ref))
ret = tracing_sched_register();
if (ret) {
pr_info("error registering scheduler trace\n");
return ret;
}
return register_tracer(&sched_switch_trace);
}
device_initcall(init_sched_switch_trace);
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