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=-2.2 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 3820FC2BD09 for ; Thu, 5 Dec 2019 18:17:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0CA652464E for ; Thu, 5 Dec 2019 18:17:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CA652464E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A52E76B1184; Thu, 5 Dec 2019 13:17:30 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A02E66B1185; Thu, 5 Dec 2019 13:17:30 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 919806B1186; Thu, 5 Dec 2019 13:17:30 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id 7B1166B1184 for ; Thu, 5 Dec 2019 13:17:30 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 134D96115 for ; Thu, 5 Dec 2019 18:17:30 +0000 (UTC) X-FDA: 76231895460.03.air43_7ba5f8c90050e X-HE-Tag: air43_7ba5f8c90050e X-Filterd-Recvd-Size: 2538 Received: from gentwo.org (gentwo.org [3.19.106.255]) by imf14.hostedemail.com (Postfix) with ESMTP for ; Thu, 5 Dec 2019 18:17:29 +0000 (UTC) Received: by gentwo.org (Postfix, from userid 1002) id 013E93EA37; Thu, 5 Dec 2019 18:17:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by gentwo.org (Postfix) with ESMTP id F0A2E3E951; Thu, 5 Dec 2019 18:17:28 +0000 (UTC) Date: Thu, 5 Dec 2019 18:17:28 +0000 (UTC) From: Christopher Lameter X-X-Sender: cl@www.lameter.com To: Qian Cai cc: Yang Shi , fabecassis@nvidia.com, jhubbard@nvidia.com, mhocko@suse.com, vbabka@suse.cz, mgorman@techsingularity.net, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [v2 PATCH] mm: move_pages: return valid node id in status if the page is already on the target node In-Reply-To: <1707CDD0-E05E-411A-A093-35E8E50ACA4B@lca.pw> Message-ID: References: <1707CDD0-E05E-411A-A093-35E8E50ACA4B@lca.pw> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="531401748-729306102-1575569848=:9722" X-Bogosity: Ham, tests=bogofilter, spamicity=0.231496, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --531401748-729306102-1575569848=:9722 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Thu, 5 Dec 2019, Qian Cai wrote: > > On Dec 5, 2019, at 12:39 PM, Yang Shi wr= ote: > > > > There are definitely a few inconsistencies, but I think the manpage i= s quite clear for this specific case, which says "status is an array of i= ntegers that return the status of each page. The array contains valid val= ues only if move_pages() did not return an error." And, it looks kernel j= ust misbehaved since 4.17 due to the fixes commit, so it sounds like a re= gression too. > > =E2=80=9COnly if=E2=80=9D in strictly logical term does not necessaril= y mean it must contain valid values if move_pages() succeed. The intended meaning is that valid values in the status array are provide= d when the syscall succeeds and not otherwise. In the error case there may be some valid values but since the operation may have aborted not all values may have a value. --531401748-729306102-1575569848=:9722--