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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8BA31C33C99 for ; Wed, 8 Jan 2020 01:20:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CC202075A for ; Wed, 8 Jan 2020 01:20:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727069AbgAHBUQ (ORCPT ); Tue, 7 Jan 2020 20:20:16 -0500 Received: from mga05.intel.com ([192.55.52.43]:41392 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725601AbgAHBUP (ORCPT ); Tue, 7 Jan 2020 20:20:15 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Jan 2020 17:20:15 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,408,1571727600"; d="scan'208";a="271694238" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by FMSMGA003.fm.intel.com with ESMTP; 07 Jan 2020 17:20:15 -0800 Date: Tue, 7 Jan 2020 17:20:15 -0800 From: Sean Christopherson To: Barret Rhoden Cc: Liran Alon , Paolo Bonzini , Dan Williams , David Hildenbrand , Dave Jiang , Alexander Duyck , linux-nvdimm@lists.01.org, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jason.zeng@intel.com Subject: Re: [PATCH v5 2/2] kvm: Use huge pages for DAX-backed files Message-ID: <20200108012014.GF16987@linux.intel.com> References: <20191212182238.46535-1-brho@google.com> <20191212182238.46535-3-brho@google.com> <06108004-1720-41EB-BCAB-BFA8FEBF4772@oracle.com> <65FB6CC1-3AD2-4D6F-9481-500BD7037203@oracle.com> <20191213171950.GA31552@linux.intel.com> <20200107190522.GA16987@linux.intel.com> <08a36944-ad5a-ca49-99b3-d3908ce0658b@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08a36944-ad5a-ca49-99b3-d3908ce0658b@google.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, Jan 07, 2020 at 02:19:06PM -0500, Barret Rhoden wrote: > On 1/7/20 2:05 PM, Sean Christopherson wrote: > >Hopefully you haven't put too much effort into the rework, because I want > >to commandeer the proposed changes and use them as the basis for a more > >aggressive overhaul of KVM's hugepage handling. Ironically, there's a bug > >in KVM's THP handling that I _think_ can be avoided by using the DAX > >approach of walking the host PTEs. > > > >I'm in the process of testing, hopefully I'll get a series sent out later > >today. If not, I should at least be able to provide an update. > > Nice timing. I was just about to get back to this, so I haven't put any > time in yet. =) > > Please CC me, and I'll try your patches out on my end. Will do. Barring last minute hiccups, the code is ready, just need to finish off a few changelogs. Should get it out early tomorrow. One question that may help avoid some churn: are huge DAX pages not tracked as compound pages? The comment from your/this patch is pretty unequivocal, but I wanted to double check that they will really return false for PageCompound(), as opposed to only returning false for PageTransCompoundMap(). /* * DAX pages do not use compound pages. ... */ Thanks!