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Subject[PATCH 3/7] ftrace, perf: Add open/close tracepoint perf registration actions
Date
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 evet.

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

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
---
include/linux/ftrace_event.h | 6 +-
kernel/trace/trace.h | 5 ++
kernel/trace/trace_event_perf.c | 116 +++++++++++++++++++++++++--------------
kernel/trace/trace_events.c | 10 ++-
kernel/trace/trace_kprobe.c | 6 ++-
kernel/trace/trace_syscalls.c | 14 +++-
6 files changed, 106 insertions(+), 51 deletions(-)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index c3da42d..195e360 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -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;
@@ -157,7 +159,7 @@ 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;
@@ -165,7 +167,7 @@ struct ftrace_event_class {
};

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,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 41c54e3..85732a8 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -828,4 +828,9 @@ extern const char *__stop___trace_bprintk_fmt[];
FTRACE_ENTRY(call, struct_name, id, PARAMS(tstruct), PARAMS(print))
#include "trace_entries.h"

+#ifdef CONFIG_PERF_EVENTS
+int perf_ftrace_event_register(struct ftrace_event_call *call,
+ enum trace_reg type, void *data);
+#endif
+
#endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 19a359d..0cfcc37 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -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;
@@ -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;

@@ -108,6 +102,69 @@ fail:
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;
@@ -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;
@@ -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)
{
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index c212a7f..5138fea 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -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:
@@ -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;
@@ -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:
@@ -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 "
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 00d527c..5667f89 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -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;

@@ -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;
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index cb65454..6916b0d 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -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);
@@ -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:
@@ -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:
@@ -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;
--
1.7.1


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