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=-8.3 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 C64D6C4321E for ; Fri, 7 Sep 2018 00:53:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E81720844 for ; Fri, 7 Sep 2018 00:53:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Z2cr6syi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E81720844 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729691AbeIGFbc (ORCPT ); Fri, 7 Sep 2018 01:31:32 -0400 Received: from mail-wr1-f42.google.com ([209.85.221.42]:41022 "EHLO mail-wr1-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727589AbeIGFbb (ORCPT ); Fri, 7 Sep 2018 01:31:31 -0400 Received: by mail-wr1-f42.google.com with SMTP id z96-v6so13192440wrb.8 for ; Thu, 06 Sep 2018 17:53:21 -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=rd6eALKTNqqfQLHfhhe4ckDvE/jeVYQ61VcErCB4W5A=; b=Z2cr6syi3jzioa2siVXqCOV4rf8nB+yT/dZqG6Ur58XOBojUWvTF19SoMxLQ93Clk9 NTh1pdRvbh6r8ez59DL+xUDdmrWs7j23yg5gHEdELItNqjUm6qz6D3wFsgblg0ybB/Y3 XKxmYn7BLKFkNABLM8/3yxbW0DVJ5l+laKoyzT3piKBIWmQItGFiSYZS/djl7jOInm7H LZ0q8yM4bGQITQG96ymgPI4f533uCo7eCF64pRqxqrvOZA0I+M3zfDS5JnOnPFXF12t6 qecN8baeuI8hgotnI3e0uv+Vp00xwbU16lk7fv3zlhUB0sxzgsY+IeqJlRZtdvdQUVa7 W7TA== 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=rd6eALKTNqqfQLHfhhe4ckDvE/jeVYQ61VcErCB4W5A=; b=Xi2QJNvo87Nvz3KFQ/qV4gNYIjQObPermeuCXe/pQRky4kfiOdsJF8rmgNWKsLYAZ+ fBq7yZSnQFsEoH6Zf6hAVQUxreOR952vTin4/2ZGNX3qhQFC6K6M0DsLbCI593ymHKsC IbVSXNR4E6zUDG8BJOtGD68NDkTlSkZ8+oNcB6BHuDTghplphWXG80KJE5756iDPEMOc iwb8FN9/rJVwrvmXuubPTUZ60jggdhpM4WmuvPKE0wB7z6VJAHp3Dzd6pMDKXJMtWw6H IniolcBTY7Q0MWNMuLdKSYZrMfxxxWdCDsbRWfCK+5fy5//24ND1I5Q+NTQG7d5TQI6V bdVQ== X-Gm-Message-State: APzg51DGc+1N+VLyVgtsKKw0MfPiCDx/Rlp7vaxCSO/mloDFqmsyAd3W g7sdKST3nyHVBI8yA89V4eR6aRzVrXwXYpTVTkN4zA== X-Google-Smtp-Source: ANB0VdZX+7iFtsp9sNXLTIsnlvgQ48UKyd6p785fYgERn3UVbONzOQIhT5UU/qhE7jyhZAWRMKDRus7OX0/s4lNS5Pc= X-Received: by 2002:a5d:61c1:: with SMTP id q1-v6mr4502340wrv.33.1536281599858; Thu, 06 Sep 2018 17:53:19 -0700 (PDT) MIME-Version: 1.0 References: <1dc80ff6-f53f-ae89-be29-3408bf7d69cc@oracle.com> <01000165aa490dc9-64abf872-afd1-4a81-a46d-a50d0131de93-000000@email.amazonses.com> <877ejzqtdy.fsf@yhuang-dev.intel.com> In-Reply-To: From: Hugh Dickins Date: Thu, 6 Sep 2018 17:52:53 -0700 Message-ID: Subject: Re: Plumbers 2018 - Performance and Scalability Microconference To: Mike Kravetz Cc: "Huang, Ying" , Christoph Lameter , daniel.m.jordan@oracle.com, linux-kernel , linux-mm , aaron.lu@intel.com, alex.kogan@oracle.com, Andrew Morton , boqun.feng@gmail.com, brouer@redhat.com, Davidlohr Bueso , dave.dice@oracle.com, dhaval.giani@oracle.com, ktkhai@virtuozzo.com, Laurent Dufour , Pavel.Tatashin@microsoft.com, Paul McKenney , shady.issa@oracle.com, tariqt@mellanox.com, Thomas Gleixner , Tim Chen , Vlastimil Babka , longman@redhat.com, Yang Shi , shy828301@gmail.com, subhra.mazumdar@oracle.com, Steven Sistare , Jonathan Adams , Ashwin Chaugule , Salman Qazi , Shakeel Butt , Michel Lespinasse , David Rientjes , Junaid Shahid , Neha Agarwal , Greg Thelen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 6, 2018 at 2:36 PM Mike Kravetz wrote: > > On 09/05/2018 06:58 PM, Huang, Ying wrote: > > Hi, Christopher, > > > > Christopher Lameter writes: > > > >> On Tue, 4 Sep 2018, Daniel Jordan wrote: > >> > >>> - Promoting huge page usage: With memory sizes becoming ever larger, huge > >>> pages are becoming more and more important to reduce TLB misses and the > >>> overhead of memory management itself--that is, to make the system scalable > >>> with the memory size. But there are still some remaining gaps that prevent > >>> huge pages from being deployed in some situations, such as huge page > >>> allocation latency and memory fragmentation. > >> > >> You forgot the major issue that huge pages in the page cache are not > >> supported and thus we have performance issues with fast NVME drives that > >> are now able to do 3Gbytes per sec that are only possible to reach with > >> directio and huge pages. > > > > Yes. That is an important gap for huge page. Although we have huge > > page cache support for tmpfs, we lacks that for normal file systems. > > > >> IMHO the huge page issue is just the reflection of a certain hardware > >> manufacturer inflicting pain for over a decade on its poor users by not > >> supporting larger base page sizes than 4k. No such workarounds needed on > >> platforms that support large sizes. Things just zoom along without > >> contortions necessary to deal with huge pages etc. > >> > >> Can we come up with a 2M base page VM or something? We have possible > >> memory sizes of a couple TB now. That should give us a million or so 2M > >> pages to work with. > > > > That sounds a good idea. Don't know whether someone has tried this. > > IIRC, Hugh Dickins and some others at Google tried going down this path. > There was a brief discussion at LSF/MM. It is something I too would like > to explore in my spare time. Almost: I never tried that path myself, but mentioned that Greg Thelen had. Hugh