From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH 2/5] do_div(): generic optimization for constant divisor on 32-bit machines Date: Tue, 03 Nov 2015 10:15:13 +0100 Message-ID: <21544300.LSjO3j3Xy7@wuerfel> References: <201511031333.Yk9ngQZJ%fengguang.wu@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: Received: from mout.kundenserver.de ([212.227.17.10]:59476 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751288AbbKCJQE (ORCPT ); Tue, 3 Nov 2015 04:16:04 -0500 In-Reply-To: <201511031333.Yk9ngQZJ%fengguang.wu@intel.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: kbuild test robot Cc: Nicolas Pitre , kbuild-all@01.org, Alexey Brodkin , =?ISO-8859-1?Q?M=E5ns_Rullg=E5rd?= , rmk+kernel@arm.linux.org.uk, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org On Tuesday 03 November 2015 13:32:17 kbuild test robot wrote: > > net/can/bcm.c: In function 'bcm_proc_show': > >> net/can/bcm.c:223:1: warning: the frame size of 1156 bytes is larger than 1024 bytes [-Wframe-larger-than=] > } Interesting, that is a lot of stack for a function that only has a couple of local variables: #define IFNAMSIZ 16 char ifname[IFNAMSIZ]; struct sock *sk = (struct sock *)m->private; struct bcm_sock *bo = bcm_sk(sk); struct bcm_op *op; This is a parisc-allyesconfig kernel, so I assume that CONFIG_PROFILE_ALL_BRANCHES is on, which instruments every 'if' in the kernel. If that causes problems, we could decide to disable the do_div optimization whenever CONFIG_PROFILE_ALL_BRANCHES is enabled. Arnd