tracing: tracepoints, samples
Tracepoint example code under samples/.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: 'Peter Zijlstra' <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/samples/tracepoints/tracepoint-probe-sample.c b/samples/tracepoints/tracepoint-probe-sample.c
new file mode 100644
index 0000000..55abfdd
--- /dev/null
+++ b/samples/tracepoints/tracepoint-probe-sample.c
@@ -0,0 +1,55 @@
+/*
+ * tracepoint-probe-sample.c
+ *
+ * sample tracepoint probes.
+ */
+
+#include <linux/module.h>
+#include <linux/file.h>
+#include <linux/dcache.h>
+#include "tp-samples-trace.h"
+
+/*
+ * Here the caller only guarantees locking for struct file and struct inode.
+ * Locking must therefore be done in the probe to use the dentry.
+ */
+static void probe_subsys_event(struct inode *inode, struct file *file)
+{
+ path_get(&file->f_path);
+ dget(file->f_path.dentry);
+ printk(KERN_INFO "Event is encountered with filename %s\n",
+ file->f_path.dentry->d_name.name);
+ dput(file->f_path.dentry);
+ path_put(&file->f_path);
+}
+
+static void probe_subsys_eventb(void)
+{
+ printk(KERN_INFO "Event B is encountered\n");
+}
+
+int __init tp_sample_trace_init(void)
+{
+ int ret;
+
+ ret = register_trace_subsys_event(probe_subsys_event);
+ WARN_ON(ret);
+ ret = register_trace_subsys_eventb(probe_subsys_eventb);
+ WARN_ON(ret);
+
+ return 0;
+}
+
+module_init(tp_sample_trace_init);
+
+void __exit tp_sample_trace_exit(void)
+{
+ unregister_trace_subsys_eventb(probe_subsys_eventb);
+ unregister_trace_subsys_event(probe_subsys_event);
+}
+
+module_exit(tp_sample_trace_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("Tracepoint Probes Samples");