tracing/events: Add module tracepoints
Add trace points to trace module_load, module_free, module_get,
module_put and module_request, and use trace_event facility to
get the trace output.
Here's the sample output:
TASK-PID CPU# TIMESTAMP FUNCTION
| | | | |
<...>-42 [000] 1.758380: module_request: fb0 wait=1 call_site=fb_open
...
<...>-60 [000] 3.269403: module_load: scsi_wait_scan
<...>-60 [000] 3.269432: module_put: scsi_wait_scan call_site=sys_init_module refcnt=0
<...>-61 [001] 3.273168: module_free: scsi_wait_scan
...
<...>-1021 [000] 13.836081: module_load: sunrpc
<...>-1021 [000] 13.840589: module_put: sunrpc call_site=sys_init_module refcnt=-1
<...>-1027 [000] 13.848098: module_get: sunrpc call_site=try_module_get refcnt=0
<...>-1027 [000] 13.848308: module_get: sunrpc call_site=get_filesystem refcnt=1
<...>-1027 [000] 13.848692: module_put: sunrpc call_site=put_filesystem refcnt=0
...
modprobe-2587 [001] 1088.437213: module_load: trace_events_sample F
modprobe-2587 [001] 1088.437786: module_put: trace_events_sample call_site=sys_init_module refcnt=0
Note:
- the taints flag can be 'F', 'C' and/or 'P' if mod->taints != 0
- the module refcnt is percpu, so it can be negative in a
specific cpu
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <4A891B3C.5030608@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/module.c b/kernel/module.c
index fd141140..b182143 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -55,6 +55,11 @@
#include <linux/percpu.h>
#include <linux/kmemleak.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/module.h>
+
+EXPORT_TRACEPOINT_SYMBOL(module_get);
+
#if 0
#define DEBUGP printk
#else
@@ -940,6 +945,8 @@
if (module) {
unsigned int cpu = get_cpu();
local_dec(__module_ref_addr(module, cpu));
+ trace_module_put(module, _RET_IP_,
+ local_read(__module_ref_addr(module, cpu)));
/* Maybe they're waiting for us to drop reference? */
if (unlikely(!module_is_live(module)))
wake_up_process(module->waiter);
@@ -1491,6 +1498,8 @@
/* Free a module, remove from lists, etc (must hold module_mutex). */
static void free_module(struct module *mod)
{
+ trace_module_free(mod);
+
/* Delete from various lists */
stop_machine(__unlink_module, mod, NULL);
remove_notes_attrs(mod);
@@ -2358,6 +2367,8 @@
/* Get rid of temporary copy */
vfree(hdr);
+ trace_module_load(mod);
+
/* Done! */
return mod;