From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f200.google.com (mail-it1-f200.google.com [209.85.166.200]) by kanga.kvack.org (Postfix) with ESMTP id 141288E0002 for ; Thu, 3 Jan 2019 05:47:18 -0500 (EST) Received: by mail-it1-f200.google.com with SMTP id p21so35310429itb.8 for ; Thu, 03 Jan 2019 02:47:18 -0800 (PST) Received: from aserp2130.oracle.com (aserp2130.oracle.com. [141.146.126.79]) by mx.google.com with ESMTPS id y2si30972828iol.35.2019.01.03.02.47.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 03 Jan 2019 02:47:17 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.2 \(3445.102.3\)) Subject: Re: [PATCH] mm: Introduce page_size() From: William Kucharski In-Reply-To: <20190102130932.GH6310@bombadil.infradead.org> Date: Thu, 3 Jan 2019 03:47:02 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: References: <20181231134223.20765-1-willy@infradead.org> <87y385awg6.fsf@linux.ibm.com> <20190101063031.GD6310@bombadil.infradead.org> <87lg447knf.fsf@linux.ibm.com> <20190102031414.GG6310@bombadil.infradead.org> <0952D432-F520-4830-A1DE-479DFAD283E7@oracle.com> <20190102130932.GH6310@bombadil.infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: "Aneesh Kumar K.V" , Andrew Morton , linux-mm@kvack.org > On Jan 2, 2019, at 6:09 AM, Matthew Wilcox = wrote: >=20 > I'm not sure I agree with that. It's going to depend on exactly what = this > code is doing; I can definitely see there being places in the VM where = we > care about how this page is currently mapped, but I think those places > are probably using the wrong interface (get_user_pages()) and should > really be using an interface which doesn't exist yet (get_user_sg()). Fair enough; I also agree the VM_BUG_ON for tail pages might be a good = safety measure, at least to see if anyone ends up calling page_size() that way = at present.