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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 84A54C4361B for ; Fri, 11 Dec 2020 23:01:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EAFD221707 for ; Fri, 11 Dec 2020 23:01:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EAFD221707 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=soleen.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0E9056B0036; Fri, 11 Dec 2020 18:01:12 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 073196B005C; Fri, 11 Dec 2020 18:01:12 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E7C726B005D; Fri, 11 Dec 2020 18:01:11 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0067.hostedemail.com [216.40.44.67]) by kanga.kvack.org (Postfix) with ESMTP id CEFC86B0036 for ; Fri, 11 Dec 2020 18:01:11 -0500 (EST) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8EEA3180C44D0 for ; Fri, 11 Dec 2020 23:01:11 +0000 (UTC) X-FDA: 77582523942.06.laugh15_6214efd27404 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin06.hostedemail.com (Postfix) with ESMTP id 5E79B10035117 for ; Fri, 11 Dec 2020 23:01:11 +0000 (UTC) X-HE-Tag: laugh15_6214efd27404 X-Filterd-Recvd-Size: 4113 Received: from mail-ej1-f65.google.com (mail-ej1-f65.google.com [209.85.218.65]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Fri, 11 Dec 2020 23:01:10 +0000 (UTC) Received: by mail-ej1-f65.google.com with SMTP id g20so14577986ejb.1 for ; Fri, 11 Dec 2020 15:01:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=GFKYVdHrtwiwhpkA9Do2VXDD8m9+meK8R9Kfm6AFeIA=; b=G2L4nkG+2a86HWG47Xy/ZeS/JPagQ4S1iIDkdkmNZpGdbylfdMtdumDUhfYLrN36a6 r9FcBfGlLA7oNgYPSWV1452G0gLBfHfX9R/E5/r9UdnLW8lnvQ9LqoFZS0YtcXAwMTIX gW/an9znixcgNfMIT+JAL8lkvMRONvK7hFpqDrxZFOfOTLhQoEt41+mGqIIqueIZOVkf +2Emj+V3RHlGGQ8M73ZLp4PsvMdlvnmx8o3rxEp/h/EkVuvAKo1vK/N/tIALBi1PsdR/ 0Oc78b1RKA5d6ZjtGsNlOeTt8MfSltcvsCZvL9Ufh4LISbNNGeOZBvy/dNtQL1IyQsJe 4oaw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=GFKYVdHrtwiwhpkA9Do2VXDD8m9+meK8R9Kfm6AFeIA=; b=GWMcvK64eNNmmbwPgeSon5I/KlfuS90AzuI35PbMmehiguLyyPBLDLf1sMBHWzKute Ohr6q/nskyMYXypv+kCs03ip3VzAi1VNNglx0capti/yJVPX2YfjUVARZG6S08SI2gg3 Zp9XjCShqJbuJDGl9znwo3zdpubLoCAoe+Kb+kGM0KJGCgQouMaxXOwRIznJ4OabwLlU H5K3lQn8uOeIDBLu6Em6lmTwCMOhwQtXxgY/2chMT9y3z9YM2cQSDj8oQGnu0xGOZnRp mYXfJD1H2/ir5bHAxfYo2O49sxkoeVtD9TXjw1RjDzsx9KfDnemdkDu/2a7MUy2p1tHk PLsw== X-Gm-Message-State: AOAM5316JqQN0sFFWeWKiyHEjacOEATBQYPXmqHaC04iCLY7olQAECI9 zw3A1ifFft5iUtB8oMbSmmYjzp+OG1NXp336jfiNaw== X-Google-Smtp-Source: ABdhPJyqbqsuDfUDja0QJ+RweV4KYLSy8rVso6oP4CDyyGfCYOb553/fgMxzadNtHa9ok0zws+8ygrJLM02XhpZm984= X-Received: by 2002:a17:906:fb9b:: with SMTP id lr27mr13275461ejb.175.1607727669571; Fri, 11 Dec 2020 15:01:09 -0800 (PST) MIME-Version: 1.0 References: <447A41F3-EB94-4DA4-8B98-038B127774A5@redhat.com> In-Reply-To: <447A41F3-EB94-4DA4-8B98-038B127774A5@redhat.com> From: Pavel Tatashin Date: Fri, 11 Dec 2020 18:00:33 -0500 Message-ID: Subject: Re: [PATCH v3 5/6] mm/gup: migrate pinned pages out of movable zone To: David Hildenbrand Cc: Jason Gunthorpe , LKML , linux-mm , Andrew Morton , Vlastimil Babka , Michal Hocko , Oscar Salvador , Dan Williams , Sasha Levin , Tyler Hicks , Joonsoo Kim , mike.kravetz@oracle.com, Steven Rostedt , Ingo Molnar , Peter Zijlstra , Mel Gorman , Matthew Wilcox , David Rientjes , John Hubbard , Linux Doc Mailing List Content-Type: text/plain; charset="UTF-8" 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: > 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. > > a) out of memory: smells like a zone setup issue. Failures are acceptable I guess. > > b) short term pinnings: process dying - not relevant I guess. Other cases? (Fork?) > > c) ? > > Once we clarified that, we actually know how likely it will be to return an error (and making vfio pinnings fail etc).