linux-kernel - Re: [RFC][PATCH] tracing/module: Move tracepoint out of module.h

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Date:	Thu, 26 Jan 2012 09:36:46 -0500
From:	Steven Rostedt <rostedt@...dmis.org>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Rusty Russell <rusty@...tcorp.com.au>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Li Zefan <lizf@...fujitsu.com>
Subject: Re: [RFC][PATCH] tracing/module: Move tracepoint out of module.h

On Thu, 2012-01-26 at 09:04 -0500, Steven Rostedt wrote:
> [ Added Li who added the original tracepoint ]
> 
> On Thu, 2012-01-26 at 14:55 +0100, Ingo Molnar wrote:
> > * Steven Rostedt <rostedt@...dmis.org> wrote:
> > 
> > > On Thu, 2012-01-26 at 11:28 +0100, Ingo Molnar wrote:
> > > 
> > > > How much more do we save if we move all of try_module_get() out 
> > > > of line? It still seems a rather thick inline function with 
> > > > preempt section and all. I'd *really* suggest that it should all 
> > > > be uninlined.
> > > > 
> > > 
> > > Here's the #'s
> > > 
> > >    text	   data	    bss	    dec	    hex	filename
> > > 7489488	2249584	9719808	19458880	128eb40	vmlinux-prepatch
> > >    text	   data	    bss	    dec	    hex	filename
> > > 7482458	2248048	9719808	19450314	128c9ca	vmlinux-postpatch
> > >    text	   data	    bss	    dec	    hex	filename
> > > 7477393	2248080	9719808	19445281	128b621	vmlinux-updatedpatch


New numbers:

   text	   data	    bss	    dec	    hex	filename
7476509	2248048	9719808	19444365	128b28d	vmlinux-updatedpatch2

Just 916 bytes savings more. But gets rid of the hot path changes.

New patch below: (and the IP still works)

-- Steve

diff --git a/include/linux/module.h b/include/linux/module.h
index 3cb7839..ef928b9 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -21,8 +21,6 @@
 #include <linux/percpu.h>
 #include <asm/module.h>
 
-#include <trace/events/module.h>
-
 /* Not Yet Implemented */
 #define MODULE_SUPPORTED_DEVICE(name)
 
@@ -439,36 +437,8 @@ void __symbol_put(const char *symbol);
 #define symbol_put(x) __symbol_put(MODULE_SYMBOL_PREFIX #x)
 void symbol_put_addr(void *addr);
 
-/* Sometimes we know we already have a refcount, and it's easier not
-   to handle the error case (which only happens with rmmod --wait). */
-static inline void __module_get(struct module *module)
-{
-	if (module) {
-		preempt_disable();
-		__this_cpu_inc(module->refptr->incs);
-		trace_module_get(module, _THIS_IP_);
-		preempt_enable();
-	}
-}
-
-static inline int try_module_get(struct module *module)
-{
-	int ret = 1;
-
-	if (module) {
-		preempt_disable();
-
-		if (likely(module_is_live(module))) {
-			__this_cpu_inc(module->refptr->incs);
-			trace_module_get(module, _THIS_IP_);
-		} else
-			ret = 0;
-
-		preempt_enable();
-	}
-	return ret;
-}
-
+extern void __module_get(struct module *module);
+extern int try_module_get(struct module *module);
 extern void module_put(struct module *module);
 
 #else /*!CONFIG_MODULE_UNLOAD*/
diff --git a/kernel/module.c b/kernel/module.c
index 178333c..c3dca5c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -928,6 +928,38 @@ void module_put(struct module *module)
 }
 EXPORT_SYMBOL(module_put);
 
+/* Sometimes we know we already have a refcount, and it's easier not
+   to handle the error case (which only happens with rmmod --wait). */
+void __module_get(struct module *module)
+{
+	if (module) {
+		preempt_disable();
+		__this_cpu_inc(module->refptr->incs);
+		trace_module_get(module, _RET_IP_);
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL(__module_get);
+
+int try_module_get(struct module *module)
+{
+	int ret = 1;
+
+	if (module) {
+		preempt_disable();
+
+		if (likely(module_is_live(module))) {
+			__this_cpu_inc(module->refptr->incs);
+			trace_module_get(module, _RET_IP_);
+		} else
+			ret = 0;
+
+		preempt_enable();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(try_module_get);
+
 #else /* !CONFIG_MODULE_UNLOAD */
 static inline void print_unload_info(struct seq_file *m, struct module *mod)
 {


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