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=-1.0 required=3.0 tests=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 035F4C33C9E for ; Thu, 30 Jan 2020 12:02:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C18B220702 for ; Thu, 30 Jan 2020 12:02:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C18B220702 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 608A16B0340; Thu, 30 Jan 2020 07:02:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5926C6B0341; Thu, 30 Jan 2020 07:02:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 45C146B0342; Thu, 30 Jan 2020 07:02:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0175.hostedemail.com [216.40.44.175]) by kanga.kvack.org (Postfix) with ESMTP id 2D3D96B0340 for ; Thu, 30 Jan 2020 07:02:57 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id DA63E824805A for ; Thu, 30 Jan 2020 12:02:56 +0000 (UTC) X-FDA: 76434164352.27.horn43_7101a927e0a61 X-HE-Tag: horn43_7101a927e0a61 X-Filterd-Recvd-Size: 3368 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Thu, 30 Jan 2020 12:02:56 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id k11so3693768wrd.9 for ; Thu, 30 Jan 2020 04:02:56 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=PXJWX2zI/JSBgEXdeTT2YWS+/RJ56LXcmiP58AIC6fw=; b=B/Kqzt1WPAIr3U0viKil0jKwya3CeMAq3M4iInKspp/FGDWOf16IGw8wRrLEatEtib A7mAt4bV1ajGpUxGpHDQNoxUHUlBUytoNczC2gghu4yJD8O/dUyw1JW6NWtsFiBDokgN FDOPLqExVPT+cLOjXqxuZIDs/tqao/he/wBiszdkDWoEvGFCTfPnD5nB/CMEofesO2wp EIWlnOmrY7e6DjbAiWxzWUDTL4ks7xxSFsWxPIpOM1tA6zh1dlRozoAECfCR63b3umv5 PSWJahRREEph4yKM0pzA3uXP+F4dlP6hU+d9JNwnELsaImp9ThJoHHPo6TyJtAIebltP xdOg== X-Gm-Message-State: APjAAAVAe3pfkr6g/vmuTDizH9mA54XNXUQ23rvE5TFZJ0hy40NjEC3R TkaWHG+bmkH61GuK72G/Tj4= X-Google-Smtp-Source: APXvYqyaLvD8q8tKyIb+hw3kUODevmo5lXICKwIVfKW2L2p5bMVVBOae6j8IBnWxNsLXb6bRV5zLLA== X-Received: by 2002:adf:ecc2:: with SMTP id s2mr5269504wro.263.1580385775342; Thu, 30 Jan 2020 04:02:55 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id o4sm6892192wrw.97.2020.01.30.04.02.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Jan 2020 04:02:54 -0800 (PST) Date: Thu, 30 Jan 2020 13:02:53 +0100 From: Michal Hocko To: Vlastimil Babka Cc: Yang Shi , mtk.manpages@gmail.com, akpm@linux-foundation.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [v2 PATCH] move_pages.2: Returning positive value is a new error case Message-ID: <20200130120253.GU24244@dhcp22.suse.cz> References: <1580334531-80354-1-git-send-email-yang.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 30-01-20 10:06:28, Vlastimil Babka wrote: > On 1/29/20 10:48 PM, Yang Shi wrote: > > Since commit a49bd4d71637 ("mm, numa: rework do_pages_move"), > > the semantic of move_pages() has changed to return the number of > > non-migrated pages if they were result of a non-fatal reasons (usually a > > busy page). This was an unintentional change that hasn't been noticed > > except for LTP tests which checked for the documented behavior. > > > > There are two ways to go around this change. We can even get back to the > > original behavior and return -EAGAIN whenever migrate_pages is not able > > The manpage says EBUSY, not EAGAIN? And should its description be > updated too? The idea was that we _could_ return EAGAIN from the syscall if migrate_pages > 0. > I.e. that it's no longer returned since 4.17? I am pretty sure this will require a deeper consideration. Do we return EIO/EINVAL? -- Michal Hocko SUSE Labs