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=-2.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_NEOMUTT autolearn=unavailable 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 439ADC31E44 for ; Wed, 12 Jun 2019 02:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1930D20896 for ; Wed, 12 Jun 2019 02:07:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=shutemov-name.20150623.gappssmtp.com header.i=@shutemov-name.20150623.gappssmtp.com header.b="MTtnxOj8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406579AbfFLCHw (ORCPT ); Tue, 11 Jun 2019 22:07:52 -0400 Received: from mail-ed1-f53.google.com ([209.85.208.53]:41790 "EHLO mail-ed1-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404880AbfFLCHv (ORCPT ); Tue, 11 Jun 2019 22:07:51 -0400 Received: by mail-ed1-f53.google.com with SMTP id p15so23055997eds.8 for ; Tue, 11 Jun 2019 19:07:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=e3TEzE60VRj/MS8YEEehOOQckYotYtM00jSjKCi8/jI=; b=MTtnxOj8b/+TTYuM6NNkobIsRNOElKsc/8BqXi3Y/+dNGP7+MZ2IGVtBb9IvQn+OsO vW74urYy7EzW8nl+nFudq/JabGlvyX3vo/5Hnrim+qNbyvWWoh95wiXSZNopPL+oXF/O eD2Pnlv4mFpK9NfsXHt421c7OE1+1LjF2t546fw5c+ALo6qKpb5Up3nS2VgDyXsEYmXu 0EFS1eXIH10mQztjtBB9u+208ddm8dhgPx+iDuc40U2BU6O0uLBWML0c78uHFi1gvuAk cpkYbNvZV5mNIS/64Z1tTp9WdsscxLL6ysWN85wbls6CM1baoMoKiseSgh4yK5TDDiHE ByZw== 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:user-agent; bh=e3TEzE60VRj/MS8YEEehOOQckYotYtM00jSjKCi8/jI=; b=Va40DPM1MtgQKNm72Ti0VdMU3RieGVeBCTPdcw4W9TwtANH3AbuwzVT8VxYg10s1Sn QZHSXClrQyWIn6KsL/pJMNOncwm1p7L0Y9TnL65NTEkwQcNkS/m1oQDuxV0JIXt4nEKQ WvspL2IjYXt92ChVTZGOq46N/9WTwcoGtKJRyV2DX6FkdJjqbtSHuMt7WK5qqWWFFvR3 kJOUnpdouo9suCuqKRgJOCeMv2PDGuTX7wVpWwcFN61nDaVsz6pTkc1yOjxxDUHXWzmP gCTMegKZQKhxk/j070vjSae6uGwDhlPnCyr5+30MQnxXh1byCD7n08/lRIDQvefuhDvg Ra7A== X-Gm-Message-State: APjAAAVQ06z+gKQpDCWYKaHHLdaKrIM9QuJO6uoglDrWbQH1T341POZR FJ6AbWsRyfwXHi7jJYr1DD6jIw== X-Google-Smtp-Source: APXvYqz0F/coC3G7qHRNAuBkWxFLoYTo3WBL7aSNleJKw+ls654OvYPBn0myZDv5kyjEpbjibAS9FA== X-Received: by 2002:a17:906:7d4e:: with SMTP id l14mr19826791ejp.188.1560305270074; Tue, 11 Jun 2019 19:07:50 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id v18sm3176634edq.80.2019.06.11.19.07.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 Jun 2019 19:07:49 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id ECA1F10081B; Wed, 12 Jun 2019 05:07:49 +0300 (+03) Date: Wed, 12 Jun 2019 05:07:49 +0300 From: "Kirill A. Shutemov" To: Larry Bassel Cc: mike.kravetz@oracle.com, willy@infradead.org, dan.j.williams@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org Subject: Re: [PATCH, RFC 2/2] Implement sharing/unsharing of PMDs for FS/DAX Message-ID: <20190612020749.sjpuquzxrprkalfy@box> References: <1557417933-15701-1-git-send-email-larry.bassel@oracle.com> <1557417933-15701-3-git-send-email-larry.bassel@oracle.com> <20190514130147.2pk2xx32aiomm57b@box> <20190524160711.GF19025@ubuette> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190524160711.GF19025@ubuette> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 24, 2019 at 09:07:11AM -0700, Larry Bassel wrote: > Again, I don't think this can happen in DAX. The only sharing allowed > is for FS/DAX/2MiB pagesize. Hm. I still don't follow. How do you guarantee that DAX actually allocated continues space for the file on backing storage and you can map it with PMD page? I believe you don't have such guarantee. -- Kirill A. Shutemov