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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 AA985C43460 for ; Thu, 15 Apr 2021 22:22:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8ECEB610F7 for ; Thu, 15 Apr 2021 22:22:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237129AbhDOWXL (ORCPT ); Thu, 15 Apr 2021 18:23:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237420AbhDOWXD (ORCPT ); Thu, 15 Apr 2021 18:23:03 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A8F4C061763; Thu, 15 Apr 2021 15:22:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=yCQQJkhIcMUmiG+jHzQ5AkwvKN7ARCVTOi/VwlhPfFg=; b=G7souXSd1HEpHpbqWUh5lxEnqG 72yPOet6m6dISSd7axpLwF1GuIay1RV/45F6tKEj6BDbJeHO2gR22kOlntma0FZZPbcvmmD/MXrGS ZotJA+5b3Jkfa2AaHAwGam44BVigQtO2OUUWx5K1MxtG1pZ5CiucXxAz7iHzXIdBtZHCcO6t1Akn0 Jf6e7BP75Cnv6p6VHUjizlw9iKFlwP1TXfBnuT7H8BBwGli/+jYj8lop4Y87z4ime9iPQZllplUcx wCGblTZ9lVpuPqcW+hkdOWg1I0lN04CeqlSLB7/d6d7euI/yXPCIGsLBBIFSox+o2XhR8MFrZidLv V60jL89w==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lXANH-0099VJ-Ux; Thu, 15 Apr 2021 22:22:19 +0000 Date: Thu, 15 Apr 2021 23:22:11 +0100 From: Matthew Wilcox To: David Laight Cc: Jesper Dangaard Brouer , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "netdev@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mips@vger.kernel.org" , Ilias Apalodimas , Matteo Croce , Grygorii Strashko , Arnd Bergmann , Christoph Hellwig Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210415222211.GG2531743@casper.infradead.org> References: <20210411103318.GC2531743@casper.infradead.org> <20210412011532.GG2531743@casper.infradead.org> <20210414101044.19da09df@carbon> <20210414115052.GS2531743@casper.infradead.org> <20210414211322.3799afd4@carbon> <20210414213556.GY2531743@casper.infradead.org> <20210415200832.32796445@carbon> <20210415182155.GD2531743@casper.infradead.org> <5179a01a462f43d6951a65de2a299070@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5179a01a462f43d6951a65de2a299070@AcuMS.aculab.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Apr 15, 2021 at 09:11:56PM +0000, David Laight wrote: > Isn't it possible to move the field down one long? > This might require an explicit zero - but this is not a common > code path - the extra write will be noise. Then it overlaps page->mapping. See emails passim.