1 files changed, 103 insertions, 149 deletions

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index cb817a2..df175cb 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -9,25 +9,27 @@
 #include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
-#include <linux/marker.h>
 #include <linux/ftrace.h>
+#include <trace/sched.h>
 
 #include "trace.h"
 
 static struct trace_array	*ctx_trace;
 static int __read_mostly	tracer_enabled;
-static atomic_t			sched_ref;
+static int			sched_ref;
+static DEFINE_MUTEX(sched_register_mutex);
 
 static void
-sched_switch_func(void *private, void *__rq, struct task_struct *prev,
+probe_sched_switch(struct rq *__rq, struct task_struct *prev,
 			struct task_struct *next)
 {
-	struct trace_array **ptr = private;
-	struct trace_array *tr = *ptr;
 	struct trace_array_cpu *data;
 	unsigned long flags;
-	long disabled;
 	int cpu;
+	int pc;
+
+	if (!sched_ref)
+		return;
 
 	tracing_record_cmdline(prev);
 	tracing_record_cmdline(next);
@@ -35,183 +37,95 @@ sched_switch_func(void *private, void *__rq, struct task_struct *prev,
 	if (!tracer_enabled)
 		return;
 
+	pc = preempt_count();
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
+	data = ctx_trace->data[cpu];
 
-	if (likely(disabled == 1))
-		tracing_sched_switch_trace(tr, data, prev, next, flags);
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
 
-	atomic_dec(&data->disabled);
 	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));
-
-	/*
-	 * 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 *private, void *__rq, struct task_struct *wakee, struct
-			task_struct *curr)
+probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee, int success)
 {
-	struct trace_array **ptr = private;
-	struct trace_array *tr = *ptr;
 	struct trace_array_cpu *data;
 	unsigned long flags;
-	long disabled;
-	int cpu;
+	int cpu, pc;
 
-	if (!tracer_enabled)
+	if (!likely(tracer_enabled))
 		return;
 
-	tracing_record_cmdline(curr);
+	pc = preempt_count();
+	tracing_record_cmdline(current);
 
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
-	data = tr->data[cpu];
-	disabled = atomic_inc_return(&data->disabled);
+	data = ctx_trace->data[cpu];
 
-	if (likely(disabled == 1))
-		tracing_sched_wakeup_trace(tr, data, wakee, curr, flags);
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
+					   flags, pc);
 
-	atomic_dec(&data->disabled);
 	local_irq_restore(flags);
 }
 
-static notrace void
-wake_up_callback(void *probe_data, void *call_data,
-		 const char *format, va_list *args)
-{
-	struct task_struct *curr;
-	struct task_struct *task;
-	struct rq *__rq;
-
-	if (likely(!tracer_enabled))
-		return;
-
-	/* 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));
-
-	tracing_record_cmdline(task);
-	tracing_record_cmdline(curr);
-
-	wakeup_func(probe_data, __rq, task, curr);
-}
-
-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->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);
+	ret = register_trace_sched_wakeup(probe_sched_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" 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);
+	ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
 	if (ret) {
-		pr_info("wakeup trace: Couldn't add marker"
+		pr_info("wakeup trace: Couldn't activate tracepoint"
 			" 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);
+	ret = register_trace_sched_switch(probe_sched_switch);
 	if (ret) {
-		pr_info("sched trace: Couldn't add marker"
+		pr_info("sched trace: Couldn't activate tracepoint"
 			" 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);
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup);
 fail_deprobe:
-	marker_probe_unregister("kernel_sched_wakeup",
-				wake_up_callback,
-				&ctx_trace);
+	unregister_trace_sched_wakeup(probe_sched_wakeup);
 	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);
+	unregister_trace_sched_switch(probe_sched_switch);
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup);
+	unregister_trace_sched_wakeup(probe_sched_wakeup);
 }
 
 static void tracing_start_sched_switch(void)
 {
-	long ref;
-
-	ref = atomic_inc_return(&sched_ref);
-	if (ref == 1)
+	mutex_lock(&sched_register_mutex);
+	if (!(sched_ref++))
 		tracing_sched_register();
+	mutex_unlock(&sched_register_mutex);
 }
 
 static void tracing_stop_sched_switch(void)
 {
-	long ref;
-
-	ref = atomic_dec_and_test(&sched_ref);
-	if (ref)
+	mutex_lock(&sched_register_mutex);
+	if (!(--sched_ref))
 		tracing_sched_unregister();
+	mutex_unlock(&sched_register_mutex);
 }
 
 void tracing_start_cmdline_record(void)
@@ -224,40 +138,86 @@ void tracing_stop_cmdline_record(void)
 	tracing_stop_sched_switch();
 }
 
+/**
+ * tracing_start_sched_switch_record - start tracing context switches
+ *
+ * Turns on context switch tracing for a tracer.
+ */
+void tracing_start_sched_switch_record(void)
+{
+	if (unlikely(!ctx_trace)) {
+		WARN_ON(1);
+		return;
+	}
+
+	tracing_start_sched_switch();
+
+	mutex_lock(&sched_register_mutex);
+	tracer_enabled++;
+	mutex_unlock(&sched_register_mutex);
+}
+
+/**
+ * tracing_stop_sched_switch_record - start tracing context switches
+ *
+ * Turns off context switch tracing for a tracer.
+ */
+void tracing_stop_sched_switch_record(void)
+{
+	mutex_lock(&sched_register_mutex);
+	tracer_enabled--;
+	WARN_ON(tracer_enabled < 0);
+	mutex_unlock(&sched_register_mutex);
+
+	tracing_stop_sched_switch();
+}
+
+/**
+ * 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;
+}
+
 static void start_sched_trace(struct trace_array *tr)
 {
-	sched_switch_reset(tr);
-	tracing_start_cmdline_record();
-	tracer_enabled = 1;
+	tracing_reset_online_cpus(tr);
+	tracing_start_sched_switch_record();
 }
 
 static void stop_sched_trace(struct trace_array *tr)
 {
-	tracer_enabled = 0;
-	tracing_stop_cmdline_record();
+	tracing_stop_sched_switch_record();
 }
 
-static void sched_switch_trace_init(struct trace_array *tr)
+static int sched_switch_trace_init(struct trace_array *tr)
 {
 	ctx_trace = tr;
-
-	if (tr->ctrl)
-		start_sched_trace(tr);
+	start_sched_trace(tr);
+	return 0;
 }
 
 static void sched_switch_trace_reset(struct trace_array *tr)
 {
-	if (tr->ctrl)
+	if (sched_ref)
 		stop_sched_trace(tr);
 }
 
-static void sched_switch_trace_ctrl_update(struct trace_array *tr)
+static void sched_switch_trace_start(struct trace_array *tr)
 {
-	/* When starting a new trace, reset the buffers */
-	if (tr->ctrl)
-		start_sched_trace(tr);
-	else
-		stop_sched_trace(tr);
+	tracing_reset_online_cpus(tr);
+	tracing_start_sched_switch();
+}
+
+static void sched_switch_trace_stop(struct trace_array *tr)
+{
+	tracing_stop_sched_switch();
 }
 
 static struct tracer sched_switch_trace __read_mostly =
@@ -265,7 +225,8 @@ static struct tracer sched_switch_trace __read_mostly =
 	.name		= "sched_switch",
 	.init		= sched_switch_trace_init,
 	.reset		= sched_switch_trace_reset,
-	.ctrl_update	= sched_switch_trace_ctrl_update,
+	.start		= sched_switch_trace_start,
+	.stop		= sched_switch_trace_stop,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest    = trace_selftest_startup_sched_switch,
 #endif
@@ -273,14 +234,7 @@ 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);
+