tracing: convert c/p state power tracer to use tracepoints

Convert the c/p state "power" tracer to use tracepoints. Avoids a
function call when the tracer is disabled.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>

1 files changed, 102 insertions, 71 deletions

diff --git a/kernel/trace/trace_power.c b/kernel/trace/trace_power.c
index b1d0d087d3a6..91ce672fb037 100644
--- a/kernel/trace/trace_power.c
+++ b/kernel/trace/trace_power.c
@@ -21,15 +21,116 @@
 static struct trace_array *power_trace;
 static int __read_mostly trace_power_enabled;
 
+static void probe_power_start(struct power_trace *it, unsigned int type,
+                                unsigned int level)
+{
+        if (!trace_power_enabled)
+                return;
+
+        memset(it, 0, sizeof(struct power_trace));
+        it->state = level;
+        it->type = type;
+        it->stamp = ktime_get();
+}
+
+
+static void probe_power_end(struct power_trace *it)
+{
+        struct ring_buffer_event *event;
+        struct trace_power *entry;
+        struct trace_array_cpu *data;
+        struct trace_array *tr = power_trace;
+
+        if (!trace_power_enabled)
+                return;
+
+        preempt_disable();
+        it->end = ktime_get();
+        data = tr->data[smp_processor_id()];
+
+        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
+                                          sizeof(*entry), 0, 0);
+        if (!event)
+                goto out;
+        entry   = ring_buffer_event_data(event);
+        entry->state_data = *it;
+        trace_buffer_unlock_commit(tr, event, 0, 0);
+ out:
+        preempt_enable();
+}
+
+static void probe_power_mark(struct power_trace *it, unsigned int type,
+                                unsigned int level)
+{
+        struct ring_buffer_event *event;
+        struct trace_power *entry;
+        struct trace_array_cpu *data;
+        struct trace_array *tr = power_trace;
+
+        if (!trace_power_enabled)
+                return;
+
+        memset(it, 0, sizeof(struct power_trace));
+        it->state = level;
+        it->type = type;
+        it->stamp = ktime_get();
+        preempt_disable();
+        it->end = it->stamp;
+        data = tr->data[smp_processor_id()];
+
+        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
+                                          sizeof(*entry), 0, 0);
+        if (!event)
+                goto out;
+        entry   = ring_buffer_event_data(event);
+        entry->state_data = *it;
+        trace_buffer_unlock_commit(tr, event, 0, 0);
+ out:
+        preempt_enable();
+}
+
+static int tracing_power_register(void)
+{
+        int ret;
+
+        ret = register_trace_power_start(probe_power_start);
+        if (ret) {
+                pr_info("power trace: Couldn't activate tracepoint"
+                        " probe to trace_power_start\n");
+                return ret;
+        }
+        ret = register_trace_power_end(probe_power_end);
+        if (ret) {
+                pr_info("power trace: Couldn't activate tracepoint"
+                        " probe to trace_power_end\n");
+                goto fail_start;
+        }
+        ret = register_trace_power_mark(probe_power_mark);
+        if (ret) {
+                pr_info("power trace: Couldn't activate tracepoint"
+                        " probe to trace_power_mark\n");
+                goto fail_end;
+        }
+        return ret;
+fail_end:
+        unregister_trace_power_end(probe_power_end);
+fail_start:
+        unregister_trace_power_start(probe_power_start);
+        return ret;
+}
 
 static void start_power_trace(struct trace_array *tr)
 {
         trace_power_enabled = 1;
+        tracing_power_register();
 }
 
 static void stop_power_trace(struct trace_array *tr)
 {
         trace_power_enabled = 0;
+        unregister_trace_power_start(probe_power_start);
+        unregister_trace_power_end(probe_power_end);
+        unregister_trace_power_mark(probe_power_mark);
 }
 
 
@@ -39,6 +140,7 @@ static int power_trace_init(struct trace_array *tr)
         power_trace = tr;
 
         trace_power_enabled = 1;
+        tracing_power_register();
 
         for_each_cpu(cpu, cpu_possible_mask)
                 tracing_reset(tr, cpu);
@@ -95,74 +197,3 @@ static int init_power_trace(void)
         return register_tracer(&power_tracer);
 }
 device_initcall(init_power_trace);
-
-void trace_power_start(struct power_trace *it, unsigned int type,
-                         unsigned int level)
-{
-        if (!trace_power_enabled)
-                return;
-
-        memset(it, 0, sizeof(struct power_trace));
-        it->state = level;
-        it->type = type;
-        it->stamp = ktime_get();
-}
-EXPORT_SYMBOL_GPL(trace_power_start);
-
-
-void trace_power_end(struct power_trace *it)
-{
-        struct ring_buffer_event *event;
-        struct trace_power *entry;
-        struct trace_array_cpu *data;
-        struct trace_array *tr = power_trace;
-
-        if (!trace_power_enabled)
-                return;
-
-        preempt_disable();
-        it->end = ktime_get();
-        data = tr->data[smp_processor_id()];
-
-        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
-                                          sizeof(*entry), 0, 0);
-        if (!event)
-                goto out;
-        entry   = ring_buffer_event_data(event);
-        entry->state_data = *it;
-        trace_buffer_unlock_commit(tr, event, 0, 0);
- out:
-        preempt_enable();
-}
-EXPORT_SYMBOL_GPL(trace_power_end);
-
-void trace_power_mark(struct power_trace *it, unsigned int type,
-                         unsigned int level)
-{
-        struct ring_buffer_event *event;
-        struct trace_power *entry;
-        struct trace_array_cpu *data;
-        struct trace_array *tr = power_trace;
-
-        if (!trace_power_enabled)
-                return;
-
-        memset(it, 0, sizeof(struct power_trace));
-        it->state = level;
-        it->type = type;
-        it->stamp = ktime_get();
-        preempt_disable();
-        it->end = it->stamp;
-        data = tr->data[smp_processor_id()];
-
-        event = trace_buffer_lock_reserve(tr, TRACE_POWER,
-                                          sizeof(*entry), 0, 0);
-        if (!event)
-                goto out;
-        entry   = ring_buffer_event_data(event);
-        entry->state_data = *it;
-        trace_buffer_unlock_commit(tr, event, 0, 0);
- out:
-        preempt_enable();
-}
-EXPORT_SYMBOL_GPL(trace_power_mark);