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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 6DC85C433E0 for ; Wed, 17 Mar 2021 21:25:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BDDBE64DAE for ; Wed, 17 Mar 2021 21:25:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BDDBE64DAE Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 11D8F6B0070; Wed, 17 Mar 2021 17:25:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0CCCE6B0071; Wed, 17 Mar 2021 17:25:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ED62C6B0072; Wed, 17 Mar 2021 17:25:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id D4D646B0070 for ; Wed, 17 Mar 2021 17:25:52 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 9A477180AD83E for ; Wed, 17 Mar 2021 21:25:52 +0000 (UTC) X-FDA: 77930648544.12.B82F7B1 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) by imf17.hostedemail.com (Postfix) with ESMTP id 3C3344000353 for ; Wed, 17 Mar 2021 21:25:52 +0000 (UTC) Received: by mail-ej1-f51.google.com with SMTP id l4so625051ejc.10 for ; Wed, 17 Mar 2021 14:25:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RWcOSSbP27/RBMgQWe11X/aJCQVEZ7g4yrghOGqiUdw=; b=G01FSC0WdaRw6SoJwmrtuo3o+0nBq50lAKF0vYw+O5GLViuiT9CjymaK2TMd68YDxc akyZ3CzMGnXOn1egPwiucNYPgXcWyMBPP0RZm2lhbN9Hwigt1GoT1lDEH/T5l54wuQa+ /DOjjG2rFtESBup+N1zxrM5caaIQOPdHbhLA0B/5Y7DWzioZ/RHMYegEXM+gyBbP07v2 6HeVccbZMsVEKWhodp1rOvHQmg+c8UAWd8elENbAAmIFd1fWh99BgA6x54OtFLYHvxpM tC8S09D4O8wrWRh2zUMRMIaOcgJPma3daJOYKaFjNnWEXiMD+XwWcpgeCIRNCrmJY937 6m4w== 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=RWcOSSbP27/RBMgQWe11X/aJCQVEZ7g4yrghOGqiUdw=; b=d2lCVpwGXzw76jPR3eXrLdR5FpUQ7gdph8Csuwt7WjWC/Egxdk0od/aqtd8UlxHpfK NH9AkIqcnzXFhoRwMnpKl4QMAUigYWfTG7PNxEOFjPG9q4G2pshopgSnM732bGdMuPlW cwtBOLrvtpbV/47k1Nmtk/9E5j/Tbl5etg7erJ+84GYuOmJo2rw4WEVAItMhjffB0Drl hJheWOm+U7CUXcIo5vHJY4u0vFId4M9dVrdSR72KKYe4NvLvNXPXw1Jprd8ejKyi729o 6+3j7n9WxRh59AhEVGh4K7PdlIVGUeRg4gt3u6x/HTqMxYcdXotv76QoFNKVI/ZjGaZA CWPw== X-Gm-Message-State: AOAM531PLUyDIH+IP8cZnS3N7tnvETuUH9sqHQkTq3u2ceLKTHGWLAzs 4u0+/9RpKH8lsaFEPUvELNRFfv5Iovd5iT4ykJAA8A== X-Google-Smtp-Source: ABdhPJyW21ya2MEzz1lGrPkE8yW6bR6Gw1paHRM622UMolppSnjoVAKlLNbZhpyPGThWRRkWRPec4nVVgJk8A2Z9sr0= X-Received: by 2002:a17:906:25c4:: with SMTP id n4mr37937861ejb.359.1616016350818; Wed, 17 Mar 2021 14:25:50 -0700 (PDT) MIME-Version: 1.0 References: <20210303175235.3308220-1-bgeffon@google.com> <20210317191334.564944-1-bgeffon@google.com> <20210317204015.GM395976@xz-x1> <20210317211857.GN395976@xz-x1> In-Reply-To: <20210317211857.GN395976@xz-x1> From: Brian Geffon Date: Wed, 17 Mar 2021 17:25:14 -0400 Message-ID: Subject: Re: [PATCH v2 1/2] mm: Allow non-VM_DONTEXPAND and VM_PFNMAP mappings with MREMAP_DONTUNMAP To: Peter Xu 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 Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: pgnkag3ujisbhb9ngat3fw3g65wb95ss X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3C3344000353 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=mail-ej1-f51.google.com; client-ip=209.85.218.51 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616016352-274850 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: You're 100% correct, I'll mail a new patch in a few Brian On Wed, Mar 17, 2021 at 5:19 PM Peter Xu wrote: > > 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 >