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Message-ID: <4BA97FA7.6040406@cn.fujitsu.com>
Date: Wed, 24 Mar 2010 10:57:43 +0800
From: Li Zefan <lizf@...fujitsu.com>
To: Steven Rostedt <rostedt@...dmis.org>
CC: Randy Dunlap <randy.dunlap@...cle.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Ingo Molnar <mingo@...e.hu>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 1/3] tracing: Reduce overhead of module tracepoints
Remove the @refcnt argument, because it has side-effects, and
arguments with side-effects are not skipped by the jump over
disabled instrumentation, so it adds overhead even when the
tracepoints are disabled.
Signed-off-by: Li Zefan <lizf@...fujitsu.com>
---
include/linux/module.h | 6 ++----
include/trace/events/module.h | 14 +++++++-------
kernel/module.c | 3 +--
3 files changed, 10 insertions(+), 13 deletions(-)
diff --git a/include/linux/module.h b/include/linux/module.h
index 5e869ff..393ec39 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -460,8 +460,7 @@ static inline void __module_get(struct module *module)
if (module) {
preempt_disable();
__this_cpu_inc(module->refptr->count);
- trace_module_get(module, _THIS_IP_,
- __this_cpu_read(module->refptr->count));
+ trace_module_get(module, _THIS_IP_);
preempt_enable();
}
}
@@ -475,8 +474,7 @@ static inline int try_module_get(struct module *module)
if (likely(module_is_live(module))) {
__this_cpu_inc(module->refptr->count);
- trace_module_get(module, _THIS_IP_,
- __this_cpu_read(module->refptr->count));
+ trace_module_get(module, _THIS_IP_);
}
else
ret = 0;
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 4b0f48b..a585f81 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -53,9 +53,9 @@ TRACE_EVENT(module_free,
DECLARE_EVENT_CLASS(module_refcnt,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt),
+ TP_ARGS(mod, ip),
TP_STRUCT__entry(
__field( unsigned long, ip )
@@ -65,7 +65,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
TP_fast_assign(
__entry->ip = ip;
- __entry->refcnt = refcnt;
+ __entry->refcnt = __this_cpu_read(mod->refptr->count);
__assign_str(name, mod->name);
),
@@ -75,16 +75,16 @@ DECLARE_EVENT_CLASS(module_refcnt,
DEFINE_EVENT(module_refcnt, module_get,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt)
+ TP_ARGS(mod, ip)
);
DEFINE_EVENT(module_refcnt, module_put,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt)
+ TP_ARGS(mod, ip)
);
TRACE_EVENT(module_request,
diff --git a/kernel/module.c b/kernel/module.c
index c968d36..21591ad 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -800,8 +800,7 @@ void module_put(struct module *module)
preempt_disable();
__this_cpu_dec(module->refptr->count);
- trace_module_put(module, _RET_IP_,
- __this_cpu_read(module->refptr->count));
+ trace_module_put(module, _RET_IP_);
/* Maybe they're waiting for us to drop reference? */
if (unlikely(!module_is_live(module)))
wake_up_process(module->waiter);
--
1.6.3
--
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