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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 254B8C43457 for ; Tue, 13 Oct 2020 02:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF76C221EB for ; Tue, 13 Oct 2020 02:45:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VBUKIfL8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726785AbgJMCp0 (ORCPT ); Mon, 12 Oct 2020 22:45:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726511AbgJMCpZ (ORCPT ); Mon, 12 Oct 2020 22:45:25 -0400 Received: from mail-oi1-x244.google.com (mail-oi1-x244.google.com [IPv6:2607:f8b0:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C476FC0613D0; Mon, 12 Oct 2020 19:45:25 -0700 (PDT) Received: by mail-oi1-x244.google.com with SMTP id l85so20889260oih.10; Mon, 12 Oct 2020 19:45:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vZTbY4ShhrUv//2VK29yAWGy/g3LO64/rb+sQCyegOQ=; b=VBUKIfL8soO6/VWyli861iToCaYbpd+QOyNJbE+8U5PLnX9wGz2xXhYmNSouy4f0Md iig+kLaS/LdoCnY5iiTjitLUKUHg6SeXJpnJuG+zruwehAtH10ksY2mEMVihvo7ygVQ4 nFyyt3X+FY/FSftH5/xKqAAnYz1pACXmPOu5VnxsySouxk3nf/a3McUZyYS50bHTjwM7 eexOBDVEKDpkbdE84sIEUboP3yXcxahKdz7Td96ur7WcgbcXFyxSXxg5TjSr+YhD2I9k o+jq9+WS8g4VPaML2qqldtmAvLY/AYFtFr7Bxl3ydKjdFHYx0AD+HXTcGqaEmmRh1cyM 4LWg== 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=vZTbY4ShhrUv//2VK29yAWGy/g3LO64/rb+sQCyegOQ=; b=axT9EPk3SSbHzHPx7fMk5XjRNKb5d3S63H2jkxSCYq/6RFUFfX0qBzyueNszQBpqXN tr4BvIL2+AIrnPMzOFveJ1W8KdoziAukrWgVwg1x4Iloii6NjVj2v8gblYy5XLAKGIyG cqAN7NOy2MozmUtuQFoosD02f3AyHxCshAx9mNeZZbk9lR4/8gASCLFBRJj+p9L030Fe w2L+eCvpHBBo6ds8UXCH3TqwNp0u8UY8oIuAD1seoFUISzrFqjD4iRWOt5e3wkeZS90O MsayvRsuOMoobdGdabZfiUbJFaugj1f4O4h66CowlBcHQbj5mgK5EqkcWqrdLbagTJ34 uX4g== X-Gm-Message-State: AOAM531FJglwylS8LXKkhlBmQ6VqWbH5Hf9xEPPF5suJ6kkXvZb83uAa B7pQKtnLurkVgqGJIKMx0NPBRH6qeXysvGXegOg= X-Google-Smtp-Source: ABdhPJzXv8XjFlSJhZQcHJtIqnVcHRwWkhQpDEv50RxyifDLE0hGnMIkdx5eZHJ0yf+Ul5ig1if0+P9WDPQt+UvXks4= X-Received: by 2002:aca:f455:: with SMTP id s82mr13204747oih.40.1602557125107; Mon, 12 Oct 2020 19:45:25 -0700 (PDT) MIME-Version: 1.0 References: <678F3D1BB717D949B966B68EAEB446ED49E01801@dggemm526-mbx.china.huawei.com> In-Reply-To: <678F3D1BB717D949B966B68EAEB446ED49E01801@dggemm526-mbx.china.huawei.com> From: yulei zhang Date: Tue, 13 Oct 2020 10:45:14 +0800 Message-ID: Subject: Re: [PATCH 00/35] Enhance memory utilization with DMEMFS To: "Zengtao (B)" Cc: "akpm@linux-foundation.org" , "naoya.horiguchi@nec.com" , "viro@zeniv.linux.org.uk" , "pbonzini@redhat.com" , "linux-fsdevel@vger.kernel.org" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "xiaoguangrong.eric@gmail.com" , "kernellwp@gmail.com" , "lihaiwei.kernel@gmail.com" , Yulei Zhang Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Oct 12, 2020 at 7:57 PM Zengtao (B) wrote: > > > > -----Original Message----- > > From: yulei.kernel@gmail.com [mailto:yulei.kernel@gmail.com] > > Sent: Thursday, October 08, 2020 3:54 PM > > To: akpm@linux-foundation.org; naoya.horiguchi@nec.com; > > viro@zeniv.linux.org.uk; pbonzini@redhat.com > > Cc: linux-fsdevel@vger.kernel.org; kvm@vger.kernel.org; > > linux-kernel@vger.kernel.org; xiaoguangrong.eric@gmail.com; > > kernellwp@gmail.com; lihaiwei.kernel@gmail.com; Yulei Zhang > > Subject: [PATCH 00/35] Enhance memory utilization with DMEMFS > > > > From: Yulei Zhang > > > > In current system each physical memory page is assocaited with > > a page structure which is used to track the usage of this page. > > But due to the memory usage rapidly growing in cloud environment, > > we find the resource consuming for page structure storage becomes > > highly remarkable. So is it an expense that we could spare? > > > > This patchset introduces an idea about how to save the extra > > memory through a new virtual filesystem -- dmemfs. > > > > Dmemfs (Direct Memory filesystem) is device memory or reserved > > memory based filesystem. This kind of memory is special as it > > is not managed by kernel and most important it is without 'struct page'. > > Therefore we can leverage the extra memory from the host system > > to support more tenants in our cloud service. > > > > We uses a kernel boot parameter 'dmem=' to reserve the system > > memory when the host system boots up, the details can be checked > > in /Documentation/admin-guide/kernel-parameters.txt. > > > > Theoretically for each 4k physical page it can save 64 bytes if > > we drop the 'struct page', so for guest memory with 320G it can > > save about 5G physical memory totally. > > Sounds interesting, but seems your patch only support x86, have you > considered aarch64? > > Regards > Zengtao Thanks, so far we only verify it on x86 server, may extend to arm platform in the future.