trace: stop all recording to ring buffer on ftrace_dump

[safe/jmp/linux-2.6] / kernel / trace / trace_sched_switch.c

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 91c699b..df175cb 100644 (file)
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -49,7 +49,7 @@ probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 }
 
 static void
-probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
+probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 {
        struct trace_array_cpu *data;
        unsigned long flags;
@@ -72,16 +72,6 @@ probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
        local_irq_restore(flags);
 }
 
-static void sched_switch_reset(struct trace_array *tr)
-{
-       int cpu;
-
-       tr->time_start = ftrace_now(tr->cpu);
-
-       for_each_online_cpu(cpu)
-               tracing_reset(tr, cpu);
-}
-
 static int tracing_sched_register(void)
 {
        int ret;
@@ -125,20 +115,16 @@ static void tracing_sched_unregister(void)
 static void tracing_start_sched_switch(void)
 {
        mutex_lock(&sched_register_mutex);
-       if (!(sched_ref++)) {
-               tracer_enabled = 1;
+       if (!(sched_ref++))
                tracing_sched_register();
-       }
        mutex_unlock(&sched_register_mutex);
 }
 
 static void tracing_stop_sched_switch(void)
 {
        mutex_lock(&sched_register_mutex);
-       if (!(--sched_ref)) {
+       if (!(--sched_ref))
                tracing_sched_unregister();
-               tracer_enabled = 0;
-       }
        mutex_unlock(&sched_register_mutex);
 }
 
@@ -152,43 +138,80 @@ void tracing_stop_cmdline_record(void)
        tracing_stop_sched_switch();
 }
 
-static void start_sched_trace(struct trace_array *tr)
+/**
+ * tracing_start_sched_switch_record - start tracing context switches
+ *
+ * Turns on context switch tracing for a tracer.
+ */
+void tracing_start_sched_switch_record(void)
 {
-       sched_switch_reset(tr);
-       tracing_start_cmdline_record();
+       if (unlikely(!ctx_trace)) {
+               WARN_ON(1);
+               return;
+       }
+
+       tracing_start_sched_switch();
+
+       mutex_lock(&sched_register_mutex);
+       tracer_enabled++;
+       mutex_unlock(&sched_register_mutex);
 }
 
-static void stop_sched_trace(struct trace_array *tr)
+/**
+ * tracing_stop_sched_switch_record - start tracing context switches
+ *
+ * Turns off context switch tracing for a tracer.
+ */
+void tracing_stop_sched_switch_record(void)
 {
-       tracing_stop_cmdline_record();
+       mutex_lock(&sched_register_mutex);
+       tracer_enabled--;
+       WARN_ON(tracer_enabled < 0);
+       mutex_unlock(&sched_register_mutex);
+
+       tracing_stop_sched_switch();
 }
 
-static void sched_switch_trace_init(struct trace_array *tr)
+/**
+ * tracing_sched_switch_assign_trace - assign a trace array for ctx switch
+ * @tr: trace array pointer to assign
+ *
+ * Some tracers might want to record the context switches in their
+ * trace. This function lets those tracers assign the trace array
+ * to use.
+ */
+void tracing_sched_switch_assign_trace(struct trace_array *tr)
 {
        ctx_trace = tr;
+}
 
-       if (tr->ctrl)
-               start_sched_trace(tr);
+static void start_sched_trace(struct trace_array *tr)
+{
+       tracing_reset_online_cpus(tr);
+       tracing_start_sched_switch_record();
 }
 
-static void sched_switch_trace_reset(struct trace_array *tr)
+static void stop_sched_trace(struct trace_array *tr)
 {
-       if (tr->ctrl && sched_ref)
-               stop_sched_trace(tr);
+       tracing_stop_sched_switch_record();
 }
 
-static void sched_switch_trace_ctrl_update(struct trace_array *tr)
+static int sched_switch_trace_init(struct trace_array *tr)
 {
-       /* When starting a new trace, reset the buffers */
-       if (tr->ctrl)
-               start_sched_trace(tr);
-       else
+       ctx_trace = tr;
+       start_sched_trace(tr);
+       return 0;
+}
+
+static void sched_switch_trace_reset(struct trace_array *tr)
+{
+       if (sched_ref)
                stop_sched_trace(tr);
 }
 
 static void sched_switch_trace_start(struct trace_array *tr)
 {
-       sched_switch_reset(tr);
+       tracing_reset_online_cpus(tr);
        tracing_start_sched_switch();
 }
 
@@ -197,14 +220,13 @@ static void sched_switch_trace_stop(struct trace_array *tr)
        tracing_stop_sched_switch();
 }
 
-struct tracer sched_switch_trace __read_mostly =
+static struct tracer sched_switch_trace __read_mostly =
 {
        .name           = "sched_switch",
        .init           = sched_switch_trace_init,
        .reset          = sched_switch_trace_reset,
        .start          = sched_switch_trace_start,
        .stop           = sched_switch_trace_stop,
-       .ctrl_update    = sched_switch_trace_ctrl_update,
 #ifdef CONFIG_FTRACE_SELFTEST
        .selftest    = trace_selftest_startup_sched_switch,
 #endif
@@ -215,3 +237,4 @@ __init static int init_sched_switch_trace(void)
        return register_tracer(&sched_switch_trace);
 }
 device_initcall(init_sched_switch_trace);
+