1 files changed, 211 insertions, 0 deletions

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
new file mode 100644
index 0000000..b8f56be
--- /dev/null
+++ b/kernel/trace/trace_sched_switch.c
@@ -0,0 +1,211 @@
+/*
+ * 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/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 void
+probe_sched_switch(struct rq *__rq, struct task_struct *prev,
+			struct task_struct *next)
+{
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	int cpu;
+	int pc;
+
+	if (!atomic_read(&sched_ref))
+		return;
+
+	tracing_record_cmdline(prev);
+	tracing_record_cmdline(next);
+
+	if (!tracer_enabled)
+		return;
+
+	pc = preempt_count();
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = ctx_trace->data[cpu];
+
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc);
+
+	local_irq_restore(flags);
+}
+
+static void
+probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee)
+{
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	int cpu, pc;
+
+	if (!likely(tracer_enabled))
+		return;
+
+	pc = preempt_count();
+	tracing_record_cmdline(current);
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = ctx_trace->data[cpu];
+
+	if (likely(!atomic_read(&data->disabled)))
+		tracing_sched_wakeup_trace(ctx_trace, data, wakee, current,
+					   flags, pc);
+
+	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;
+
+	ret = register_trace_sched_wakeup(probe_sched_wakeup);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup\n");
+		return ret;
+	}
+
+	ret = register_trace_sched_wakeup_new(probe_sched_wakeup);
+	if (ret) {
+		pr_info("wakeup trace: Couldn't activate tracepoint"
+			" probe to kernel_sched_wakeup_new\n");
+		goto fail_deprobe;
+	}
+
+	ret = register_trace_sched_switch(probe_sched_switch);
+	if (ret) {
+		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:
+	unregister_trace_sched_wakeup_new(probe_sched_wakeup);
+fail_deprobe:
+	unregister_trace_sched_wakeup(probe_sched_wakeup);
+	return ret;
+}
+
+static void tracing_sched_unregister(void)
+{
+	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)
+		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);