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ftrace, perf: Add open/close tracepoint perf registration actions
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Adding TRACE_REG_PERF_OPEN and TRACE_REG_PERF_CLOSE to differentiate
register/unregister from open/close actions.

The register/unregister actions are invoked for the first/last
tracepoint user when opening/closing the event.

The open/close actions are invoked for each tracepoint user when
opening/closing the event.

Link: http://lkml.kernel.org/r/1329317514-8131-3-git-send-email-jolsa@redhat.com

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Jiri Olsa authored and Steven Rostedt committed Feb 21, 2012
1 parent e248491 commit ceec0b6
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Showing 5 changed files with 101 additions and 51 deletions.
6 changes: 4 additions & 2 deletions include/linux/ftrace_event.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,8 @@ enum trace_reg {
TRACE_REG_UNREGISTER,
TRACE_REG_PERF_REGISTER,
TRACE_REG_PERF_UNREGISTER,
TRACE_REG_PERF_OPEN,
TRACE_REG_PERF_CLOSE,
};

struct ftrace_event_call;
Expand All @@ -157,15 +159,15 @@ struct ftrace_event_class {
void *perf_probe;
#endif
int (*reg)(struct ftrace_event_call *event,
enum trace_reg type);
enum trace_reg type, void *data);
int (*define_fields)(struct ftrace_event_call *);
struct list_head *(*get_fields)(struct ftrace_event_call *);
struct list_head fields;
int (*raw_init)(struct ftrace_event_call *);
};

extern int ftrace_event_reg(struct ftrace_event_call *event,
enum trace_reg type);
enum trace_reg type, void *data);

enum {
TRACE_EVENT_FL_ENABLED_BIT,
Expand Down
116 changes: 75 additions & 41 deletions kernel/trace/trace_event_perf.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,23 +44,17 @@ static int perf_trace_event_perm(struct ftrace_event_call *tp_event,
return 0;
}

static int perf_trace_event_init(struct ftrace_event_call *tp_event,
struct perf_event *p_event)
static int perf_trace_event_reg(struct ftrace_event_call *tp_event,
struct perf_event *p_event)
{
struct hlist_head __percpu *list;
int ret;
int ret = -ENOMEM;
int cpu;

ret = perf_trace_event_perm(tp_event, p_event);
if (ret)
return ret;

p_event->tp_event = tp_event;
if (tp_event->perf_refcount++ > 0)
return 0;

ret = -ENOMEM;

list = alloc_percpu(struct hlist_head);
if (!list)
goto fail;
Expand All @@ -83,7 +77,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
}
}

ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);
ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER, NULL);
if (ret)
goto fail;

Expand All @@ -108,6 +102,69 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
return ret;
}

static void perf_trace_event_unreg(struct perf_event *p_event)
{
struct ftrace_event_call *tp_event = p_event->tp_event;
int i;

if (--tp_event->perf_refcount > 0)
goto out;

tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER, NULL);

/*
* Ensure our callback won't be called anymore. The buffers
* will be freed after that.
*/
tracepoint_synchronize_unregister();

free_percpu(tp_event->perf_events);
tp_event->perf_events = NULL;

if (!--total_ref_count) {
for (i = 0; i < PERF_NR_CONTEXTS; i++) {
free_percpu(perf_trace_buf[i]);
perf_trace_buf[i] = NULL;
}
}
out:
module_put(tp_event->mod);
}

static int perf_trace_event_open(struct perf_event *p_event)
{
struct ftrace_event_call *tp_event = p_event->tp_event;
return tp_event->class->reg(tp_event, TRACE_REG_PERF_OPEN, p_event);
}

static void perf_trace_event_close(struct perf_event *p_event)
{
struct ftrace_event_call *tp_event = p_event->tp_event;
tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
}

static int perf_trace_event_init(struct ftrace_event_call *tp_event,
struct perf_event *p_event)
{
int ret;

ret = perf_trace_event_perm(tp_event, p_event);
if (ret)
return ret;

ret = perf_trace_event_reg(tp_event, p_event);
if (ret)
return ret;

ret = perf_trace_event_open(p_event);
if (ret) {
perf_trace_event_unreg(p_event);
return ret;
}

return 0;
}

int perf_trace_init(struct perf_event *p_event)
{
struct ftrace_event_call *tp_event;
Expand All @@ -130,6 +187,14 @@ int perf_trace_init(struct perf_event *p_event)
return ret;
}

void perf_trace_destroy(struct perf_event *p_event)
{
mutex_lock(&event_mutex);
perf_trace_event_close(p_event);
perf_trace_event_unreg(p_event);
mutex_unlock(&event_mutex);
}

int perf_trace_add(struct perf_event *p_event, int flags)
{
struct ftrace_event_call *tp_event = p_event->tp_event;
Expand All @@ -154,37 +219,6 @@ void perf_trace_del(struct perf_event *p_event, int flags)
hlist_del_rcu(&p_event->hlist_entry);
}

void perf_trace_destroy(struct perf_event *p_event)
{
struct ftrace_event_call *tp_event = p_event->tp_event;
int i;

mutex_lock(&event_mutex);
if (--tp_event->perf_refcount > 0)
goto out;

tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);

/*
* Ensure our callback won't be called anymore. The buffers
* will be freed after that.
*/
tracepoint_synchronize_unregister();

free_percpu(tp_event->perf_events);
tp_event->perf_events = NULL;

if (!--total_ref_count) {
for (i = 0; i < PERF_NR_CONTEXTS; i++) {
free_percpu(perf_trace_buf[i]);
perf_trace_buf[i] = NULL;
}
}
out:
module_put(tp_event->mod);
mutex_unlock(&event_mutex);
}

__kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
struct pt_regs *regs, int *rctxp)
{
Expand Down
10 changes: 7 additions & 3 deletions kernel/trace/trace_events.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,8 @@ int trace_event_raw_init(struct ftrace_event_call *call)
}
EXPORT_SYMBOL_GPL(trace_event_raw_init);

int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
int ftrace_event_reg(struct ftrace_event_call *call,
enum trace_reg type, void *data)
{
switch (type) {
case TRACE_REG_REGISTER:
Expand All @@ -170,6 +171,9 @@ int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
call->class->perf_probe,
call);
return 0;
case TRACE_REG_PERF_OPEN:
case TRACE_REG_PERF_CLOSE:
return 0;
#endif
}
return 0;
Expand Down Expand Up @@ -209,7 +213,7 @@ static int ftrace_event_enable_disable(struct ftrace_event_call *call,
tracing_stop_cmdline_record();
call->flags &= ~TRACE_EVENT_FL_RECORDED_CMD;
}
call->class->reg(call, TRACE_REG_UNREGISTER);
call->class->reg(call, TRACE_REG_UNREGISTER, NULL);
}
break;
case 1:
Expand All @@ -218,7 +222,7 @@ static int ftrace_event_enable_disable(struct ftrace_event_call *call,
tracing_start_cmdline_record();
call->flags |= TRACE_EVENT_FL_RECORDED_CMD;
}
ret = call->class->reg(call, TRACE_REG_REGISTER);
ret = call->class->reg(call, TRACE_REG_REGISTER, NULL);
if (ret) {
tracing_stop_cmdline_record();
pr_info("event trace: Could not enable event "
Expand Down
6 changes: 5 additions & 1 deletion kernel/trace/trace_kprobe.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1892,7 +1892,8 @@ static __kprobes void kretprobe_perf_func(struct kretprobe_instance *ri,
#endif /* CONFIG_PERF_EVENTS */

static __kprobes
int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
int kprobe_register(struct ftrace_event_call *event,
enum trace_reg type, void *data)
{
struct trace_probe *tp = (struct trace_probe *)event->data;

Expand All @@ -1909,6 +1910,9 @@ int kprobe_register(struct ftrace_event_call *event, enum trace_reg type)
case TRACE_REG_PERF_UNREGISTER:
disable_trace_probe(tp, TP_FLAG_PROFILE);
return 0;
case TRACE_REG_PERF_OPEN:
case TRACE_REG_PERF_CLOSE:
return 0;
#endif
}
return 0;
Expand Down
14 changes: 10 additions & 4 deletions kernel/trace/trace_syscalls.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,9 @@ static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);

static int syscall_enter_register(struct ftrace_event_call *event,
enum trace_reg type);
enum trace_reg type, void *data);
static int syscall_exit_register(struct ftrace_event_call *event,
enum trace_reg type);
enum trace_reg type, void *data);

static int syscall_enter_define_fields(struct ftrace_event_call *call);
static int syscall_exit_define_fields(struct ftrace_event_call *call);
Expand Down Expand Up @@ -649,7 +649,7 @@ void perf_sysexit_disable(struct ftrace_event_call *call)
#endif /* CONFIG_PERF_EVENTS */

static int syscall_enter_register(struct ftrace_event_call *event,
enum trace_reg type)
enum trace_reg type, void *data)
{
switch (type) {
case TRACE_REG_REGISTER:
Expand All @@ -664,13 +664,16 @@ static int syscall_enter_register(struct ftrace_event_call *event,
case TRACE_REG_PERF_UNREGISTER:
perf_sysenter_disable(event);
return 0;
case TRACE_REG_PERF_OPEN:
case TRACE_REG_PERF_CLOSE:
return 0;
#endif
}
return 0;
}

static int syscall_exit_register(struct ftrace_event_call *event,
enum trace_reg type)
enum trace_reg type, void *data)
{
switch (type) {
case TRACE_REG_REGISTER:
Expand All @@ -685,6 +688,9 @@ static int syscall_exit_register(struct ftrace_event_call *event,
case TRACE_REG_PERF_UNREGISTER:
perf_sysexit_disable(event);
return 0;
case TRACE_REG_PERF_OPEN:
case TRACE_REG_PERF_CLOSE:
return 0;
#endif
}
return 0;
Expand Down

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