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-rw-r--r--kernel/trace/trace_sched_switch.c286
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);