tracing/events: Add module tracepoints

PATCH RESEND In review Li Zefan 1 participant 2 messages Aug 17, 2009

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Tracing Module support

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Li Zefan

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2009-08-17 09:02 UTC #0 lore raw

PATCH RESEND 1/1 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 <[email protected]>

Acked-by Rusty Russell <[email protected]>

---
 include/linux/module.h        |   14 ++++-
 include/trace/events/module.h |  126 +++++++++++++++++++++++++++++++++++++++++
 kernel/kmod.c                 |    4 +
 kernel/module.c               |   11 ++++
 4 files changed, 152 insertions(+), 3 deletions(-)
 create mode 100644 include/trace/events/module.h

include/linux/module.h +11 -3

index 7a5c82c..86863cd 100644
@@ -17,10 +17,12 @@
 #include <linux/moduleparam.h>
 #include <linux/marker.h>
 #include <linux/tracepoint.h>
-#include <asm/local.h>
 
+#include <asm/local.h>
 #include <asm/module.h>
 
+#include <trace/events/module.h>
+
 /* Not Yet Implemented */
 #define MODULE_SUPPORTED_DEVICE(name)

@@ -480,7 +482,10 @@ static inline local_t *__module_ref_addr(struct module *mod, int cpu)
 static inline void __module_get(struct module *module)
 {
 	if (module) {
-		local_inc(__module_ref_addr(module, get_cpu()));
+		unsigned int cpu = get_cpu();
+		local_inc(__module_ref_addr(module, cpu));
+		trace_module_get(module, _THIS_IP_,
+				 local_read(__module_ref_addr(module, cpu)));
 		put_cpu();
 	}
 }

@@ -491,8 +496,11 @@ static inline int try_module_get(struct module *module)
 
 	if (module) {
 		unsigned int cpu = get_cpu();
-		if (likely(module_is_live(module)))
+		if (likely(module_is_live(module))) {
 			local_inc(__module_ref_addr(module, cpu));
+			trace_module_get(module, _THIS_IP_,
+				local_read(__module_ref_addr(module, cpu)));
+		}
 		else
 			ret = 0;
 		put_cpu();

include/trace/events/module.h new file +126 -0

126 lines not on this page · raw message

kernel/kmod.c +4 -0

index 385c31a..a922808 100644
@@ -37,6 +37,8 @@
 #include <linux/suspend.h>
 #include <asm/uaccess.h>
 
+#include <trace/events/module.h>
+
 extern int max_threads;
 
 static struct workqueue_struct *khelper_wq;

@@ -108,6 +110,8 @@ int __request_module(bool wait, const char *fmt, ...)
 		return -ENOMEM;
 	}
 
+	trace_module_request(module_name, wait, _RET_IP_);
+
 	ret = call_usermodehelper(modprobe_path, argv, envp,
 			wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
 	atomic_dec(&kmod_concurrent);

kernel/module.c +11 -0

index fd14114..b182143 100644
@@ -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 @@ void module_put(struct module *module)
 	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 @@ static int __unlink_module(void *_mod)
 /* 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 @@ static noinline struct module *load_module(void __user *umod,
 	/* Get rid of temporary copy */
 	vfree(hdr);
 
+	trace_module_load(mod);
+
 	/* Done! */
 	return mod;

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