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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 19ABAC3A5A2 for ; Tue, 3 Sep 2019 16:23:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC5A823431 for ; Tue, 3 Sep 2019 16:23:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EKHkp/aq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729865AbfICQXK (ORCPT ); Tue, 3 Sep 2019 12:23:10 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:34726 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729692AbfICQXK (ORCPT ); Tue, 3 Sep 2019 12:23:10 -0400 Received: by mail-wr1-f68.google.com with SMTP id s18so18212960wrn.1; Tue, 03 Sep 2019 09:23:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=TepBcnay70WrGmb0WBkOD/Cs9CShXo+TxS9/OGqh6Bw=; b=EKHkp/aqR3DigOCLFd9MIjlOwoKCQetnK8fr3HngH/gmy44B/y+LUfRJnQJYWb6Cvo 8mEv5H9vPsNOdeBU6+QazVE8YKbL4Ks0DybjlhHXBqNmcH8loNv9Yp47V1EmvhvpineH M0H4k3nAyfQh480J1dBLjqfa+BSK1wWphJaM2ef0qpf7OjVmdoHnF9SQt+HNNmNQ2at/ Y9yU3fbQC4I2CC9fwIX1huaI5p9BHj9JMlCN+EKbXwcPw3B/YI8zycMEkVzAScoOuEf1 juB1OBjcPWcL3N+j+VnKYHpHRr34IiVZ//Oo17/9CkRglejFCo2L6hRYuW4uNwWs2/er nO3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=TepBcnay70WrGmb0WBkOD/Cs9CShXo+TxS9/OGqh6Bw=; b=mDVJcfuwdqr9YWNQo95DSAOJ4+Ex/BhxIblcdPsGpZaiTdLiwxTzz2CytqX3uKFAR2 Nb+1cFSLdQ6ke/4weyXcKVOv6ZmYxaLt9a1+19BqiqyqpBD3IeMz/H5J4AFDrrQB2V8L ZRIChqxmwneojC0p2XJ8YjvSYZbYndzMdZVXTWx5jy8DrNh39/siTdbjcMJqQdSRdLWP mmv8K0h1+NwBB6bh0okcO1wsgzjRaIJO8r4zSokJfV9XtrngHbduyLnnC8AgRA3fL/7B yPrQtP+0zGI40kYAqfIRLG0tgiGJH5KSI/k3y2BEc3Ppe9c3UqAyGd5DVXZCB3mIandd w3jA== X-Gm-Message-State: APjAAAVLWd0HzAOeDMGD4VPlBZ+XbQv39sRli68MmFYHiXbRJTmOcI+w quzTu1s7bYyn7+7Vbs3bMw== X-Google-Smtp-Source: APXvYqwx0bJ6xnL9cz14xzE50FT6ThicgK4OWReQhuR8YKvDLg+VcrlLQG0HKsV1CSwULWCwxVvs1A== X-Received: by 2002:adf:f20f:: with SMTP id p15mr8540655wro.17.1567527788037; Tue, 03 Sep 2019 09:23:08 -0700 (PDT) Received: from avx2 ([46.53.254.228]) by smtp.gmail.com with ESMTPSA id c74sm11892wme.46.2019.09.03.09.23.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Sep 2019 09:23:07 -0700 (PDT) Date: Tue, 3 Sep 2019 19:23:03 +0300 From: Alexey Dobriyan To: Valentin Schneider 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 Subject: Re: [PATCH] sched: make struct task_struct::state 32-bit Message-ID: <20190903162303.GA2173@avx2> References: <20190902210558.GA23013@avx2> <7b94004e-4a65-462b-cd6b-5cbd23d607bf@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <7b94004e-4a65-462b-cd6b-5cbd23d607bf@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org 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.