From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DDD3C3A5A2 for ; Tue, 3 Sep 2019 16:33:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A3F1233A1 for ; Tue, 3 Sep 2019 16:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731144AbfICQds (ORCPT ); Tue, 3 Sep 2019 12:33:48 -0400 Received: from foss.arm.com ([217.140.110.172]:40480 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731200AbfICQbt (ORCPT ); Tue, 3 Sep 2019 12:31:49 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 80A9C360; Tue, 3 Sep 2019 09:31:48 -0700 (PDT) Received: from [10.1.194.37] (e113632-lin.cambridge.arm.com [10.1.194.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 59C973F246; Tue, 3 Sep 2019 09:31:47 -0700 (PDT) Subject: Re: [PATCH] sched: make struct task_struct::state 32-bit To: Alexey Dobriyan Cc: mingo@redhat.com, peterz@infradead.org, linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-block@vger.kernel.org, dm-devel@redhat.com, axboe@kernel.dk, aarcange@redhat.com References: <20190902210558.GA23013@avx2> <7b94004e-4a65-462b-cd6b-5cbd23d607bf@arm.com> <20190903162303.GA2173@avx2> From: Valentin Schneider Message-ID: <64003dcd-d954-b76d-856a-214ff11ac000@arm.com> Date: Tue, 3 Sep 2019 17:31:46 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190903162303.GA2173@avx2> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/09/2019 17:23, Alexey Dobriyan wrote: > On Tue, Sep 03, 2019 at 12:02:38AM +0100, Valentin Schneider wrote: >> struct task_struct { >> struct thread_info thread_info; /* 0 24 */ >> volatile int state; /* 24 4 */ >> >> /* XXX 4 bytes hole, try to pack */ >> >> void * stack; /* 32 8 */ >> >> Though seeing as this is also the boundary of the randomized layout we can't >> really do much better without changing the boundary itself. So much for >> cacheline use :/ > > Cacheline use of task_struct is pretty hopeless because of all the ifdefs. > Yeah I figured, then had a minute of silence for those forsaken bytes.