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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 34C43C352A4 for ; Mon, 10 Feb 2020 22:02:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D52302072C for ; Mon, 10 Feb 2020 22:02:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="YXmokgz/" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D52302072C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7C4566B0183; Mon, 10 Feb 2020 17:02:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7741A6B0185; Mon, 10 Feb 2020 17:02:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6629C6B0186; Mon, 10 Feb 2020 17:02:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0128.hostedemail.com [216.40.44.128]) by kanga.kvack.org (Postfix) with ESMTP id 4FF3E6B0183 for ; Mon, 10 Feb 2020 17:02:18 -0500 (EST) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id CF08445B4 for ; Mon, 10 Feb 2020 22:02:17 +0000 (UTC) X-FDA: 76475591514.09.stamp32_13f7ef4f5675a X-HE-Tag: stamp32_13f7ef4f5675a X-Filterd-Recvd-Size: 2770 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Mon, 10 Feb 2020 22:02:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=vNIOpjO6L7fkSABQvzZ43W1Bjw+erFnCyYEOfEH1MGY=; b=YXmokgz/lVSrzbyK6DCjUaE3jU cGLNCy53goDGKyLuRUYcEPIXAVR1e2SsqnJBReMnFwtlCJiW6/v7wwoA4AOMuX4ai4kmGpC8rDDfR +nnmkDJfmvj0bufKVcB/wki4DGD07GAYm5D7dUsjtF96Dfjl8w15Ynfi4BvgpXD4vXxfSfZd+E6mk qhBnc7geFz9DBqM1jsGMdvGaKogjwjlCvn23C+VYbVI8cLYQ0cF4U2SBOtBskI4ETTSS4hPKeL/VP h6biwi4o+VU2O4kCkkczdHkbnlTS5103+DF9OMMatXqnf6IQRm4XkmK0IXTKKKCBq0pzR4S+8w+2Q z2+WeqrA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1H8B-0005rq-Fo; Mon, 10 Feb 2020 22:02:15 +0000 Date: Mon, 10 Feb 2020 14:02:15 -0800 From: Matthew Wilcox To: John Hubbard Cc: "Kirill A. Shutemov" , linux-mm@kvack.org, "Kirill A . Shutemov" Subject: Re: [PATCH] mm: Improve dump_page() for compound pages Message-ID: <20200210220215.GO8731@bombadil.infradead.org> References: <20200208044415.30012-1-willy@infradead.org> <20200210124225.56cjwblfa7njgp5o@box> <92d69132-6664-3fc3-4743-11109df0b079@nvidia.com> <20200210212125.f24n5javxkfv6uvi@box> <85d46612-b5b1-f566-7026-e4fec9166c3b@nvidia.com> <20200210215449.ao7q5x4no5y2j6pc@box> <1d2ceaff-2cd5-8a03-97d0-556c1b48a69f@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1d2ceaff-2cd5-8a03-97d0-556c1b48a69f@nvidia.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000361, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Feb 10, 2020 at 02:00:39PM -0800, John Hubbard wrote: > On 2/10/20 1:54 PM, Kirill A. Shutemov wrote: > > On Mon, Feb 10, 2020 at 01:33:22PM -0800, John Hubbard wrote: > >>> PageSlab() can be called for the head page. > >> > >> > >> It's not clear to me whether it's safer to use the...user-provided page, or the > >> head page, for checking PageSlab()--it's probably set on both head and non-head > >> pages, right? > > > > PageSlab() will call compound_head() inside. > > > >> I guess you're saying it should be like this: > >> > >> mapcount = PageSlab(head) ? 0 : page_mapcount(page); > >> > >> ...yes? > > > > Yes. > > > > OK very good, thanks for walking me through it. :) > > Matthew, if you like I'll just fix it up like that for my v6 posting of the > patchset, since it's such a small change. Yes, please just fix it up.