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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,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 A31D0C433FE for ; Sat, 12 Dec 2020 00:07:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 11B76221F5 for ; Sat, 12 Dec 2020 00:07:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 11B76221F5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F2CCD6B0036; Fri, 11 Dec 2020 19:07:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EB7F36B005C; Fri, 11 Dec 2020 19:07:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D30AD6B005D; Fri, 11 Dec 2020 19:07:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id B6C316B0036 for ; Fri, 11 Dec 2020 19:07:20 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 78E31180FA162 for ; Sat, 12 Dec 2020 00:07:20 +0000 (UTC) X-FDA: 77582690640.02.cork92_3b0bf6027405 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin02.hostedemail.com (Postfix) with ESMTP id 5F0CD10097AA0 for ; Sat, 12 Dec 2020 00:07:20 +0000 (UTC) X-HE-Tag: cork92_3b0bf6027405 X-Filterd-Recvd-Size: 3801 Received: from hqnvemgate25.nvidia.com (hqnvemgate25.nvidia.com [216.228.121.64]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Sat, 12 Dec 2020 00:07:19 +0000 (UTC) Received: from hqmail.nvidia.com (Not Verified[216.228.121.13]) by hqnvemgate25.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Fri, 11 Dec 2020 16:07:18 -0800 Received: from [10.2.58.108] (172.20.145.6) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 12 Dec 2020 00:07:09 +0000 Subject: Re: [PATCH v3 5/6] mm/gup: migrate pinned pages out of movable zone To: Pavel Tatashin , David Hildenbrand CC: Jason Gunthorpe , LKML , linux-mm , Andrew Morton , Vlastimil Babka , Michal Hocko , "Oscar Salvador" , Dan Williams , "Sasha Levin" , Tyler Hicks , "Joonsoo Kim" , , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Mel Gorman , Matthew Wilcox , David Rientjes , "Linux Doc Mailing List" References: <447A41F3-EB94-4DA4-8B98-038B127774A5@redhat.com> From: John Hubbard Message-ID: <9c201f8c-6266-ed03-e419-12edd8148fdb@nvidia.com> Date: Fri, 11 Dec 2020 16:07:09 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:84.0) Gecko/20100101 Thunderbird/84.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To HQMAIL107.nvidia.com (172.20.187.13) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1607731638; bh=GE26nCzQ9HfpnpJ/4kq8ZcBVZOfOrwVSu+Matl1W4V0=; h=Subject:To:CC:References:From:Message-ID:Date:User-Agent: MIME-Version:In-Reply-To:Content-Type:Content-Language: Content-Transfer-Encoding:X-Originating-IP:X-ClientProxiedBy; b=hnjxYUKJZY/IWx8fOrko9qKAIHQ0lvPgjIe708zMbhQ6DNTfpnzpmlWTt4TFi+OqI /RbazPTJrJQWAAKMicUsQipszn5aj1fjHGUnAvfxMbW4D+7GDZbmvKuV4Q5EV9ne8Z krbF7LtVNO9bHbo77xY4AH77SzliappiRIxnAfwp77lpA0axIpo2+8uEYQyatuvCwC SAf0PNLh0OHqGujN6DbP1boYVxOKfwNWRBhYHRze9xE5sarVU1w91K/FCOfklEMyYh YAklh8SSjyngvzKoyizVo/TD1Jlct4F3UcWXvXSFCJ2Zkai9VEDXpFz9eVEFVzkzIp 4wjv2KxnqmZcw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 12/11/20 3:00 PM, Pavel Tatashin wrote: >> I guess revert what we did (unpin) and return an error. The interesting question is what can make migration/isolation fail > > OK. I will make the necessary changes. Let's handle errors properly. > Whatever the cause for the error, we will know it when it happens, and > when error is returned. I think I will add a 10-time retry instead of > the infinite retry that we currently have. The 10-times retry we > currently have during the hot-remove path. It occurs to me that maybe the pre-existing infinite loop shouldn't be there at all? Would it be better to let the callers retry? Obviously that would be a separate patch and I'm not sure it's safe to make that change, but the current loop seems buried maybe too far down. Thoughts, anyone? thanks, -- John Hubbard NVIDIA