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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,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 97CA1C2D0C8 for ; Tue, 31 Dec 2019 03:50:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70DCC206D9 for ; Tue, 31 Dec 2019 03:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726720AbfLaDuQ (ORCPT ); Mon, 30 Dec 2019 22:50:16 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:39438 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726605AbfLaDuQ (ORCPT ); Mon, 30 Dec 2019 22:50:16 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1im8Xu-0005Oc-AF; Mon, 30 Dec 2019 20:50:14 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1im8Xt-0002v1-Dx; Mon, 30 Dec 2019 20:50:14 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Yang Shi Cc: Michal Hocko , John Hubbard , "Michael Kerrisk \(man-pages\)" , cl@linux.com, cai@lca.pw, akpm@linux-foundation.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1575596090-115377-1-git-send-email-yang.shi@linux.alibaba.com> <0dc96e40-5f2b-a2fe-6e5f-b6f3d5e9ebde@nvidia.com> <95170ea5-5b62-9168-fcd9-93b43330a1b4@linux.alibaba.com> <092adc11-7039-9343-7067-0e0199c9dc13@gmail.com> <51dd767a-221f-882d-c7f6-45bd0c217a67@nvidia.com> <20191218101711.GB21485@dhcp22.suse.cz> <0059a598-5726-2488-cd37-b4b7f9b3353e@linux.alibaba.com> Date: Mon, 30 Dec 2019 21:49:03 -0600 In-Reply-To: <0059a598-5726-2488-cd37-b4b7f9b3353e@linux.alibaba.com> (Yang Shi's message of "Mon, 30 Dec 2019 19:00:43 -0800") Message-ID: <87lfqtcfyo.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1im8Xt-0002v1-Dx;;;mid=<87lfqtcfyo.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+uhutDF4Ukz8J1ef+/uLeFxpg4smyiZiY= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH] move_pages.2: not return ENOENT if the page are already on the target nodes X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org Yang Shi writes: > On 12/18/19 2:17 AM, Michal Hocko wrote: >> On Tue 17-12-19 23:36:09, John Hubbard wrote: >> [...] >>> diff --git a/man2/move_pages.2 b/man2/move_pages.2 >>> index 2d96468fa..1bf1053f2 100644 >>> --- a/man2/move_pages.2 >>> +++ b/man2/move_pages.2 >>> @@ -191,12 +191,6 @@ was specified or an attempt was made to migrate pages of a kernel thread. >>> .B ENODEV >>> One of the target nodes is not online. >>> .TP >>> -.B ENOENT >>> -No pages were found that require moving. >>> -All pages are either already >>> -on the target node, not present, had an invalid address or could not be >>> -moved because they were mapped by multiple processes. >>> -.TP >>> .B EPERM >>> The caller specified >>> .B MPOL_MF_MOVE_ALL >>> >>> ...But I'm not sure if we should change the implementation, instead, so >>> that it *can* return ENOENT. That's the main question to resolve before >>> creating any more patches, I think. >> I would start by dropping any note about ENOENT first. I am not really >> sure there is a reasonable usecase for it but maybe somebody comes up >> with something and only then we should consider it. >> >> Feel free to add >> Acked-by: Michal Hocko >> >> ideally with a kernel commit which removed the ENOENT. > > A quick audit doesn't show kernel code or comment notes about ENOENT > wrongly. The status could be set as ENOENT if the page is not present > (follow_page() returns NULL), and man page does match what kernel > does. Doesn't the function one layer up then consume the ENOENT? Eric