From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752370Ab2AZOEb (ORCPT ); Thu, 26 Jan 2012 09:04:31 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:38450 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751113Ab2AZOEa (ORCPT ); Thu, 26 Jan 2012 09:04:30 -0500 X-Authority-Analysis: v=2.0 cv=fNy7LOme c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=0LOP1KteNnsA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=70fqYcBpVrWJcohhfMQA:9 a=PUjeQqilurYA:10 a=jeBq3FmKZ4MA:10 a=ZycB6UtQUfgMyuk2+PxD7w==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.80.29 Message-ID: <1327586669.22710.89.camel@gandalf.stny.rr.com> Subject: Re: [RFC][PATCH] tracing/module: Move tracepoint out of module.h From: Steven Rostedt To: Ingo Molnar Cc: Rusty Russell , LKML , Andrew Morton , Frederic Weisbecker , Li Zefan Date: Thu, 26 Jan 2012 09:04:29 -0500 In-Reply-To: <20120126135504.GA13107@elte.hu> References: <1326754637.7642.177.camel@gandalf.stny.rr.com> <20120117095418.GG10397@elte.hu> <1326807145.17534.26.camel@gandalf.stny.rr.com> <20120118120711.GB14863@elte.hu> <1326909412.17534.91.camel@gandalf.stny.rr.com> <877h0jgx80.fsf@rustcorp.com.au> <1327545664.22710.78.camel@gandalf.stny.rr.com> <20120126102836.GD3853@elte.hu> <1327585945.22710.87.camel@gandalf.stny.rr.com> <20120126135504.GA13107@elte.hu> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.2.2-1 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Added Li who added the original tracepoint ] On Thu, 2012-01-26 at 14:55 +0100, Ingo Molnar wrote: > * Steven Rostedt 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 > > > > Thus we get an additional 5k it seems, for a total of 13k savings. > > > > The below patch is what I used. Note, since the tracepoint > > requires the instruction pointer, I created stub versions that > > call a "do_" version of the function to pass in the local > > instruction counter. > > Hm, why does this tracepoint include a flat RIP? It's pretty > superfluous as there's various other (orghogonal) ways to get at > the RIP. > > If the field is needed for compatibility then lets set it to > zero at the tracepoint level and not burden the module.h > hotpath. Perhaps I could use "__builtin_return_address(0)" instead. I'll try that out. That way, we don't burden the module hotpath, and we keep the old behavior. -- Steve