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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 AEE92C35240 for ; Thu, 30 Jan 2020 12:02:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 848E3214AF for ; Thu, 30 Jan 2020 12:02:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580385778; bh=BVs4QUFtzA7erjawnsHWCbA6wHtmxdUonKUqBzkpG5U=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=2Rci/RvzDlDHs1wiP2/ymuEE6R1+qVxqJmyY2YSIL4RQmd9i/CYwG+342kRgxJP2j qp8PdmafBhykva90Vezonr9h31PG4vN5HGkEA4jIXuSoMQJlLwsFSEBiaI7F3Ns2RN qpKeN9SRHP/KHj5x8LfVyOcFFVI6mzcwajzbmlxY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726980AbgA3MC6 (ORCPT ); Thu, 30 Jan 2020 07:02:58 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:36406 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727027AbgA3MC5 (ORCPT ); Thu, 30 Jan 2020 07:02:57 -0500 Received: by mail-wr1-f67.google.com with SMTP id z3so3747558wru.3; Thu, 30 Jan 2020 04:02:55 -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=kHhq0owAh1i6M1a7r8QO/YhWo9lNxZs6KlWiOctRSOt0jCizXdcHlB5ko+ZI3eVGlO YHzygB/7bQzMqF2YGQTWNmBbB3MNLhQsRiYgUFvU19xnHgTd0UFUzfj009td1o6IIrl8 MRyKp2OHuaagNEss7NibJMrLCPPrR/AMBwWA58LUJAvI1S+F4WVdeEwjvPU15trNmJ9m ngQXKeJJKbls43I8uMeWfJmXYAtkUu2o9tZYFibqjGLVKQe4T+FavrUE6OJrU38gE51O ru7HhxD5hujBIRXy1FcIk/dIlNo0iCfCsctYrz06S4+Kwe2rUiIY8p4tTn+ucQYoGRf7 RYjA== X-Gm-Message-State: APjAAAUHAYyTFHdZj5iigC0aXN0zJOktjD8IHVK/yt7J0ywt/osnBDC6 KpaZbK8OnBEcqpLQGBspXDc= 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: Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org 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