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=-6.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, 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 28292C433DB for ; Wed, 17 Mar 2021 21:19:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6E2764EEE for ; Wed, 17 Mar 2021 21:19:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231551AbhCQVTE (ORCPT ); Wed, 17 Mar 2021 17:19:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:46949 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230369AbhCQVTD (ORCPT ); Wed, 17 Mar 2021 17:19:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616015942; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zJuWBirWZevEe1qdUUJUM0zyPqke25oP95wtgMd+Sq8=; b=aTg/e9ZPgfAWEYs6mpO5Ag8F6NNL5WX1csSTgPgvkhx/n0lJu4mzsbatcbaRc/DYSqOGhQ Mxmf4/R+NUue3Kb/D9l60aigCQtHNxJ7Ar48/Cdm1m3ugB6s8lv9NsggXwszIUXkahJj8B UDwlyD5EAhLXqZH8xcYDb2KqEXb8QwA= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-345-nNhksLcmPTCH_8b0Ursh1Q-1; Wed, 17 Mar 2021 17:19:00 -0400 X-MC-Unique: nNhksLcmPTCH_8b0Ursh1Q-1 Received: by mail-qk1-f197.google.com with SMTP id x11so27060712qki.22 for ; Wed, 17 Mar 2021 14:19:00 -0700 (PDT) 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=zJuWBirWZevEe1qdUUJUM0zyPqke25oP95wtgMd+Sq8=; b=qUU93l0vZIs+GAvhnDhp3/ROmY6HV1btHu+gQBN89M8SxrkRmAToK/ruFLcaY5GhKn ppLqtEIS+7peodW6sT3W5KpZr13U+z3HJGYMBqCi8Lf6gYtOufm3djkA65ngg11IZKqG cjFHujPE5WTQPKQQ5IvGlA7/Qi2wQKXh3XBTbqi6ygfTekwMT7tQUn4WUjzO2zuv9x1f fqwto1hHQ3ztKIwzeQ4uUNS4YGNUXCALczT4wgTb3fZL86Y75zqEnpjacpt9OWzPVG31 EK/bGKDgX1MQdNvnKVl4/g//K8Y7MjsE/ApvbiKdbyPOz3gQHu8b+5DYqLGgMxPwRlgh zzAg== X-Gm-Message-State: AOAM532pZgfUhAlSc/bNwmXcd8DlOWavsvd3y6RG6la/lS3aP5LbX2fj vKKPmD4m+OBuiAlKgSJZCWbsxVcz+2mrBlC7GEY+qtiIigorZ08Ny5bgCdFrkTWnFEiZ4Q67quq ZNBoE0fquEfyUFJSvvmyK+Zuc X-Received: by 2002:a05:620a:85e:: with SMTP id u30mr1252416qku.427.1616015939333; Wed, 17 Mar 2021 14:18:59 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyhq6bqTA0FWK73UvJDzjgEn5ktBSk9FLI7tTjvi91rAjqHANwIaMUmYjcYzF3aSRStcgNLfQ== X-Received: by 2002:a05:620a:85e:: with SMTP id u30mr1252388qku.427.1616015939099; Wed, 17 Mar 2021 14:18:59 -0700 (PDT) Received: from xz-x1 ([142.126.89.138]) by smtp.gmail.com with ESMTPSA id h8sm146847qkk.116.2021.03.17.14.18.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Mar 2021 14:18:58 -0700 (PDT) Date: Wed, 17 Mar 2021 17:18:57 -0400 From: Peter Xu To: Brian Geffon Cc: Andrew Morton , Axel Rasmussen , Lokesh Gidra , Mike Rapoport , Hugh Dickins , "Michael S . Tsirkin" , LKML , linux-mm , Andy Lutomirski , Vlastimil Babka , Andrea Arcangeli , Sonny Rao , Minchan Kim , "Kirill A . Shutemov" , Dmitry Safonov Subject: Re: [PATCH v2 1/2] mm: Allow non-VM_DONTEXPAND and VM_PFNMAP mappings with MREMAP_DONTUNMAP Message-ID: <20210317211857.GN395976@xz-x1> References: <20210303175235.3308220-1-bgeffon@google.com> <20210317191334.564944-1-bgeffon@google.com> <20210317204015.GM395976@xz-x1> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 17, 2021 at 04:44:25PM -0400, Brian Geffon wrote: > Hi Peter, Hi, Brian, > Thank you as always for taking a look. This change relies on the > existing check in vma_to_resize on line 686: > https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L686 > which returns -EFAULT when the vma is VM_DONTEXPAND or VM_PFNMAP. Do you mean line 676? https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L676 I'm not sure whether it'll work for MREMAP_DONTUNMAP, since IIUC MREMAP_DONTUNMAP only works for the remap case with no size change, however in that case in vma_to_resize() we'll bail out even earlier than line 676 when checking against the size: https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L667 So IIUC we'll still need the change as Hugh suggested previously. Thanks, -- Peter Xu