From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2127 invoked by alias); 22 Sep 2006 02:11:49 -0000 Received: (qmail 2115 invoked by uid 22791); 22 Sep 2006 02:11:48 -0000 X-Spam-Status: No, hits=-2.4 required=5.0 tests=AWL,BAYES_00,FORGED_RCVD_HELO X-Spam-Check-By: sourceware.org Received: from tomts16.bellnexxia.net (HELO tomts16-srv.bellnexxia.net) (209.226.175.4) by sourceware.org (qpsmtpd/0.31) with ESMTP; Fri, 22 Sep 2006 02:11:41 +0000 Received: from krystal.dyndns.org ([67.68.212.231]) by tomts16-srv.bellnexxia.net (InterMail vM.5.01.06.13 201-253-122-130-113-20050324) with ESMTP id <20060922021139.RSKW27612.tomts16-srv.bellnexxia.net@krystal.dyndns.org> for ; Thu, 21 Sep 2006 22:11:39 -0400 Received: from localhost (localhost [127.0.0.1]) (uid 1000) by krystal.dyndns.org with local; Thu, 21 Sep 2006 22:01:19 -0400 id 001C2488.451343EF.00000AE2 Date: Fri, 22 Sep 2006 02:11:00 -0000 From: Mathieu Desnoyers To: Jeremy Fitzhardinge Cc: Martin Bligh , "Frank Ch. Eigler" , Masami Hiramatsu , prasanna@in.ibm.com, Andrew Morton , Ingo Molnar , Paul Mundt , linux-kernel , Jes Sorensen , Tom Zanussi , Richard J Moore , Michel Dagenais , Christoph Hellwig , Greg Kroah-Hartman , Thomas Gleixner , William Cohen , ltt-dev@shafik.org, systemtap@sources.redhat.com, Alan Cox Subject: Re: [PATCH] Linux Kernel Markers 0.7 for 2.6.17 (with type checking!) Message-ID: <20060922020119.GA28712@Krystal> References: <20060921232024.GA16155@Krystal> <451331A1.3020601@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <451331A1.3020601@goop.org> X-Editor: vi X-Info: http://krystal.dyndns.org:8080 X-Operating-System: Linux/2.4.32-grsec (i686) X-Uptime: 21:17:21 up 29 days, 22:26, 1 user, load average: 0.12, 0.14, 0.15 User-Agent: Mutt/1.5.13 (2006-08-11) X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q3/txt/msg00692.txt.bz2 * Jeremy Fitzhardinge (jeremy@goop.org) wrote: > Mathieu Desnoyers wrote: > >+#ifdef CONFIG_MARK_SYMBOL > >+#define MARK_SYM(name) \ > >+ do { \ > >+ __label__ here; \ > >+ here: asm volatile \ > >+ (MARK_KPROBE_PREFIX#name " = %0" : : "m" (*&&here)); > >\ > >+ } while(0) > >+#else > >+#define MARK_SYM(name) > >+#endif > > BTW, this won't work if you put the MARK_SYM in a loop which gcc > unrolls; you'll only get the mark in the last unrolled iteration > (because the symbol assignments will override each other). > > Do make this work properly, you really need to put the mark entries into > a separate section, so that if gcc duplicates the code, you get > duplicated markers too. > Good point, I will change it to : #define MARK_SYM(name) \ do { \ __label__ here; \ volatile static void *__mark_kprobe_##name \ asm (MARK_CALL_PREFIX#name) \ __attribute__((unused)) = &&here; \ here: \ do { } while(0); \ } while(0) Which fixes the problem. Some tests showed me that the compiler does not unroll an otherwise unrolled loop when this specific macro is called. (test done with -funroll-all-loops). Regards, Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68