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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 95684C4360F for ; Thu, 4 Apr 2019 07:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 55430214AF for ; Thu, 4 Apr 2019 07:13:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1554361998; bh=H0SYkQqKepUPt8a0R+ZbQdTTrj8kqa8aE18A99AhfWg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=z1K9Y4d/yYbEktATw2wsQk94ZMgr2GBsmeNx21UHHCbyy6rLGAd/8SVz3KlciLuYn JEXkSll+GHM9aEft9lM9nnzawPymVPyq1JIcMd6fBvRTzwjobqfJzrtUCNzAn+C3+j 6zxgV9EVsKLBt39o58u1gk7E5KrUBqaFebR9UA7c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727025AbfDDHNR (ORCPT ); Thu, 4 Apr 2019 03:13:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:43524 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726563AbfDDHNQ (ORCPT ); Thu, 4 Apr 2019 03:13:16 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 046F0B11F; Thu, 4 Apr 2019 07:13:14 +0000 (UTC) Date: Thu, 4 Apr 2019 09:13:12 +0200 From: Michal Hocko To: ziy@nvidia.com Cc: Dave Hansen , Yang Shi , Keith Busch , Fengguang Wu , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Daniel Jordan , "Kirill A . Shutemov" , Andrew Morton , Vlastimil Babka , Mel Gorman , John Hubbard , Mark Hairgrove , Nitin Gupta , Javier Cabezas , David Nellans Subject: Re: [RFC PATCH 00/25] Accelerate page migration and use memcg for PMEM management Message-ID: <20190404071312.GD12864@dhcp22.suse.cz> References: <20190404020046.32741-1-zi.yan@sent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190404020046.32741-1-zi.yan@sent.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 03-04-19 19:00:21, Zi Yan wrote: > From: Zi Yan > > Thanks to Dave Hansen's patches, which make PMEM as part of memory as NUMA nodes. > How to use PMEM along with normal DRAM remains an open problem. There are > several patchsets posted on the mailing list, proposing to use page migration to > move pages between PMEM and DRAM using Linux page replacement policy [1,2,3]. > There are some important problems not addressed in these patches: > 1. The page migration in Linux does not provide high enough throughput for us to > fully exploit PMEM or other use cases. > 2. Linux page replacement is running too infrequent to distinguish hot and cold > pages. [...] > 33 files changed, 4261 insertions(+), 162 deletions(-) For a patch _this_ large you should really start with a real world usecasing hitting bottlenecks with the current implementation. Should microbenchmarks can trigger bottlenecks much easier but do real application do the same? Please give us some numbers. -- Michal Hocko SUSE Labs