From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424911AbcFMQE1 (ORCPT ); Mon, 13 Jun 2016 12:04:27 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:55049 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1424288AbcFMQE0 (ORCPT ); Mon, 13 Jun 2016 12:04:26 -0400 From: Arnd Bergmann To: Jason Baron Cc: akpm@linux-foundation.org, joe@perches.com, peterz@infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/4] dynamic_debug: add jump label support Date: Mon, 13 Jun 2016 18:05:22 +0200 Message-ID: <3448491.s2zXTXrSlh@wuerfel> User-Agent: KMail/5.1.3 (Linux/4.4.0-22-generic; KDE/5.18.0; x86_64; ; ) In-Reply-To: <575ADDB3.7070304@akamai.com> References: <3796097.4dlb9d7Id8@wuerfel> <575ADDB3.7070304@akamai.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:WC/oLxW08h4F8z/aoKbu4PTOIdo0FJkxDIsKBDl3+paWykmC6nl q/gwzFXycJcaB++l68q7tzhZWCwqqcE/JEtrqX+94AlPP88K2LiUedSFpx0xj9PPX2N7krh unPk9bdK6DDt4YRVLmkqSwQWmo4Atr4/o9Tw0A0KDe+W/dJ3dRclOROhkYJoJIOGSnGuL2+ 8kU29H6/+UO9O+NIPLPaQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:VNzH1+i214c=:y67MDfQYn0swS5GhnPurGm qfz0pxwAi+TrEC8m/yFqtRHLuZUdnvq2WQyOvlAFIK2Xr4brMaXAOJ1GXophMteywpnjl2TRv yyt/Xp7r076Ke4srRCFJ2/tdiD3u5PmikwCapZYtxbj1h65B/B1n67PymvZFCShiXYI/ZYueQ TTj7/TItMTWY2fttP7Su49TJD11qZugebP1NctiMBfOmYzO7O9L18ZUKzFhrzl7dGYzJ8Ckhj K//T99ExB+1XPya4Ghb3Y/CREvMFx6cDU4paI+HLL1ghrZ7LJ9J+4DQKJ745ybgjidoi6oruj 6t6YZAAf1OkAa9r8VTQ41RHy2Juc2onMrX0xjen5kBSO/PQt+VxNIrbdop4QXuCE7OMJSnwmu SH6QEExXH9mQA6TkY7q8JWd7yCgE8gDHcMo6s+D7tzQuGSX7N6h2Ap0OFC1+WPiMO4lf1b4RT H6eXoLopH0+tqBkw5v70aNUHHBxDTd2gw/7ohVWr81+ToR+4Bg1lAD9hEcAXdpDQM220+A5X/ 5PbkgLurgisfd8vvBo9PpJRZ6V56XYoLEQPb3cAbw1Jg8qat2zu0HGL1sDqoLw4PF302nEtx+ LQesDBQTwMHZbQbwGViUFt2JLdTwW6qgaem/dyvOBLAmydsXlteFXwDGw3b8W/JKvLCD9+75u 2+FnVwojmXKYLmxkeo4/wNw/uUig1myVEI8HFwZaP+lYSt8Wt9XkQl1kZts95eld0fgP/pyll OEfdY00Nvq1kU5gp Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, June 10, 2016 11:33:07 AM CEST Jason Baron wrote: > On 06/10/2016 05:54 AM, Arnd Bergmann wrote: > > On Friday, May 20, 2016 5:16:36 PM CEST Jason Baron wrote: > >> Although dynamic debug is often only used for debug builds, sometimes its > >> enabled for production builds as well. Minimize its impact by using jump > >> labels. This reduces the text section by 7000+ bytes in the kernel image > >> below. It does increase data, but this should only be referenced when > >> changing the direction of the branches, and hence usually not in cache. > >> > >> text data bss dec hex filename > >> 8194852 4879776 925696 14000324 d5a0c4 vmlinux.pre > >> 8187337 4960224 925696 14073257 d6bda9 vmlinux.post > >> > >> Signed-off-by: Jason Baron > >> --- > > > > This causes problems for some of my randconfig builds, when a dynamic > > debug call is used inside of an __exit function: > > > > `.exit.text' referenced in section `__jump_table' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o > > `.exit.text' referenced in section `__jump_table' of drivers/built-in.o: defined in discarded section `.exit.text' of drivers/built-in.o > > > > I stuck pr_debug() in a few functions marked with __exit, but did not > reproduce yet. Can you share your .config and gcc --version. > I found these on ARM randconfig builds e.g. this one http://pastebin.com/raw/KjWHxnwU I also have some other patches applied that could have interacted with your change, so if you can't reproduce it easily, let me try it on a plain linux-next kernel. The compiler I use is arm-linux-gnueabi-gcc (GCC) 6.0.0 20160323 (experimental) Arnd