1 files changed, 286 insertions, 0 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
new file mode 100644
index 000000000000..cb817a209aa0
--- /dev/null
+++ b/kernel/trace/trace_sched_switch.c
@@ -0,0 +1,286 @@
+/*
+ * trace context switch
+ *
+ * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
+#include <linux/kallsyms.h>
+#include <linux/uaccess.h>
+#include <linux/marker.h>
+#include <linux/ftrace.h>
+
+#include "trace.h"
+
+static struct trace_array	*ctx_trace;
+static int __read_mostly	tracer_enabled;
+static atomic_t			sched_ref;
+
+static void
+sched_switch_func(void *private, void *__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;
+
+	tracing_record_cmdline(prev);
+	tracing_record_cmdline(next);
+
+	if (!tracer_enabled)
+		return;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = tr->data[cpu];
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1))
+		tracing_sched_switch_trace(tr, data, prev, next, flags);
+
+	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)
+{
+	struct trace_array **ptr = private;
+	struct trace_array *tr = *ptr;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+
+	if (!tracer_enabled)
+		return;
+
+	tracing_record_cmdline(curr);
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = tr->data[cpu];
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1))
+		tracing_sched_wakeup_trace(tr, data, wakee, curr, flags);
+
+	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);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't add marker"
+			" 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);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't add marker"
+			" 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);
+	if (ret) {
+		pr_info("sched trace: Couldn't add marker"
+			" 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);
+fail_deprobe:
+	marker_probe_unregister("kernel_sched_wakeup",
+				wake_up_callback,
+				&ctx_trace);
+	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);
+}
+
+static void tracing_start_sched_switch(void)
+{
+	long ref;
+
+	ref = atomic_inc_return(&sched_ref);
+	if (ref == 1)
+		tracing_sched_register();
+}
+
+static void tracing_stop_sched_switch(void)
+{
+	long ref;
+
+	ref = atomic_dec_and_test(&sched_ref);
+	if (ref)
+		tracing_sched_unregister();
+}
+
+void tracing_start_cmdline_record(void)
+{
+	tracing_start_sched_switch();
+}
+
+void tracing_stop_cmdline_record(void)
+{
+	tracing_stop_sched_switch();
+}
+
+static void start_sched_trace(struct trace_array *tr)
+{
+	sched_switch_reset(tr);
+	tracing_start_cmdline_record();
+	tracer_enabled = 1;
+}
+
+static void stop_sched_trace(struct trace_array *tr)
+{
+	tracer_enabled = 0;
+	tracing_stop_cmdline_record();
+}
+
+static void sched_switch_trace_init(struct trace_array *tr)
+{
+	ctx_trace = tr;
+
+	if (tr->ctrl)
+		start_sched_trace(tr);
+}
+
+static void sched_switch_trace_reset(struct trace_array *tr)
+{
+	if (tr->ctrl)
+		stop_sched_trace(tr);
+}
+
+static void sched_switch_trace_ctrl_update(struct trace_array *tr)
+{
+	/* When starting a new trace, reset the buffers */
+	if (tr->ctrl)
+		start_sched_trace(tr);
+	else
+		stop_sched_trace(tr);
+}
+
+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,
+#ifdef CONFIG_FTRACE_SELFTEST
+	.selftest    = trace_selftest_startup_sched_switch,
+#endif
+};
+
+__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);