From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753327Ab0CSPsi (ORCPT ); Fri, 19 Mar 2010 11:48:38 -0400 Received: from anchor-post-1.mail.demon.net ([195.173.77.132]:32891 "EHLO anchor-post-1.mail.demon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323Ab0CSPsh (ORCPT ); Fri, 19 Mar 2010 11:48:37 -0400 Message-ID: <4BA39CD1.8060900@rsk.demon.co.uk> Date: Fri, 19 Mar 2010 15:48:33 +0000 From: Richard Kennedy User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.8) Gecko/20100301 Fedora/3.0.3-1.fc12 Thunderbird/3.0.3 MIME-Version: 1.0 To: David Miller CC: tj@kernel.org, fweisbec@gmail.com, sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [BUG] percpu misaligned allocation References: <20100319013119.GB22095@nowhere> <20100318.185757.39197211.davem@davemloft.net> <4BA2DF0B.9080600@kernel.org> <20100318.200205.59696640.davem@davemloft.net> In-Reply-To: <20100318.200205.59696640.davem@davemloft.net> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/03/10 03:02, David Miller wrote: > From: Tejun Heo > Date: Fri, 19 Mar 2010 11:18:51 +0900 > >> On 03/19/2010 10:57 AM, David Miller wrote: >>> I would use u64 so something like: >>> >>> u64 [FTRACE_MAX_PROFILE_SIZE / sizeof(u64)] >> >> DIV_ROUND_UP() would be safer than division > > There's potential real trouble if it isn't a multiple of sizeof(u64) > so better: > > BUILD_BUG_ON(FTRACE_MAX_PROFILE_SIZE % sizeof(u64)); > > :-) > > What a mess, just because this thing can't be typed properly :-/ > -- > To unsubscribe from this list: send the line "unsubscribe sparclinux" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Couldn't you use a union? For example if you have union test { long t; char buffer[50]; }; gcc will then do the right thing. on x86_64 sizeof(union test) = 56 but on x86_32 it's only 52. regards Richard