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-rw-r--r--samples/trace_events/trace_custom_sched.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/samples/trace_events/trace_custom_sched.c b/samples/trace_events/trace_custom_sched.c
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+++ b/samples/trace_events/trace_custom_sched.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * event tracer
+ *
+ * Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org>
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/trace_events.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+
+/*
+ * Must include the event header that the custom event will attach to,
+ * from the C file, and not in the custom header file.
+ */
+#include <trace/events/sched.h>
+
+/* Declare CREATE_CUSTOM_TRACE_EVENTS before including custom header */
+#define CREATE_CUSTOM_TRACE_EVENTS
+
+#include "trace_custom_sched.h"
+
+/*
+ * As the trace events are not exported to modules, the use of
+ * for_each_kernel_tracepoint() is needed to find the trace event
+ * to attach to. The fct() function below, is a callback that
+ * will be called for every event.
+ *
+ * Helper functions are created by the TRACE_CUSTOM_EVENT() macro
+ * update the event. Those are of the form:
+ *
+ * trace_custom_event_<event>_update()
+ *
+ * Where <event> is the event to attach.
+ */
+static void fct(struct tracepoint *tp, void *priv)
+{
+ trace_custom_event_sched_switch_update(tp);
+ trace_custom_event_sched_waking_update(tp);
+}
+
+static int __init trace_sched_init(void)
+{
+ for_each_kernel_tracepoint(fct, NULL);
+ return 0;
+}
+
+static void __exit trace_sched_exit(void)
+{
+}
+
+module_init(trace_sched_init);
+module_exit(trace_sched_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("Custom scheduling events");
+MODULE_LICENSE("GPL");