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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2007-10-18 23:41:08 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-19 11:53:55 -0700
commit31155bc03e35a8d2b2551bc2eea3da5791e1b776 (patch)
tree64a82cd692af1dc3672d311f5788e2dc6a56e546 /samples/markers/probe-example.c
parent267c4025f2e198a4e551556a6db31a554ca51814 (diff)
Linux Kernel Markers - Samples
Module example showing how to use the Linux Kernel Markers. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'samples/markers/probe-example.c')
-rw-r--r--samples/markers/probe-example.c98
1 files changed, 98 insertions, 0 deletions
diff --git a/samples/markers/probe-example.c b/samples/markers/probe-example.c
new file mode 100644
index 000000000000..238b2e384fc8
--- /dev/null
+++ b/samples/markers/probe-example.c
@@ -0,0 +1,98 @@
+/* probe-example.c
+ *
+ * Connects two functions to marker call sites.
+ *
+ * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * This file is released under the GPLv2.
+ * See the file COPYING for more details.
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/marker.h>
+#include <asm/atomic.h>
+
+struct probe_data {
+ const char *name;
+ const char *format;
+ marker_probe_func *probe_func;
+};
+
+void probe_subsystem_event(const struct marker *mdata, void *private,
+ const char *format, ...)
+{
+ va_list ap;
+ /* Declare args */
+ unsigned int value;
+ const char *mystr;
+
+ /* Assign args */
+ va_start(ap, format);
+ value = va_arg(ap, typeof(value));
+ mystr = va_arg(ap, typeof(mystr));
+
+ /* Call printk */
+ printk(KERN_DEBUG "Value %u, string %s\n", value, mystr);
+
+ /* or count, check rights, serialize data in a buffer */
+
+ va_end(ap);
+}
+
+atomic_t eventb_count = ATOMIC_INIT(0);
+
+void probe_subsystem_eventb(const struct marker *mdata, void *private,
+ const char *format, ...)
+{
+ /* Increment counter */
+ atomic_inc(&eventb_count);
+}
+
+static struct probe_data probe_array[] =
+{
+ { .name = "subsystem_event",
+ .format = "%d %s",
+ .probe_func = probe_subsystem_event },
+ { .name = "subsystem_eventb",
+ .format = MARK_NOARGS,
+ .probe_func = probe_subsystem_eventb },
+};
+
+static int __init probe_init(void)
+{
+ int result;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(probe_array); i++) {
+ result = marker_probe_register(probe_array[i].name,
+ probe_array[i].format,
+ probe_array[i].probe_func, &probe_array[i]);
+ if (result)
+ printk(KERN_INFO "Unable to register probe %s\n",
+ probe_array[i].name);
+ result = marker_arm(probe_array[i].name);
+ if (result)
+ printk(KERN_INFO "Unable to arm probe %s\n",
+ probe_array[i].name);
+ }
+ return 0;
+}
+
+static void __exit probe_fini(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(probe_array); i++)
+ marker_probe_unregister(probe_array[i].name);
+ printk(KERN_INFO "Number of event b : %u\n",
+ atomic_read(&eventb_count));
+}
+
+module_init(probe_init);
+module_exit(probe_fini);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mathieu Desnoyers");
+MODULE_DESCRIPTION("SUBSYSTEM Probe");