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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS 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 9F855C282D7 for ; Wed, 30 Jan 2019 23:14:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B91420881 for ; Wed, 30 Jan 2019 23:14:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Ef5r+ypH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731633AbfA3XOZ (ORCPT ); Wed, 30 Jan 2019 18:14:25 -0500 Received: from aserp2130.oracle.com ([141.146.126.79]:48188 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726531AbfA3XOY (ORCPT ); Wed, 30 Jan 2019 18:14:24 -0500 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id x0UNDoAD083642; Wed, 30 Jan 2019 23:14:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=oRY8IIy+LzhfOUy5KtCkTy2Mvv+fVM7jDXgCUqjIfj0=; b=Ef5r+ypHarZqKR2GIKCNPyLlXdwxG3W4mZ4MfIHr90RgBOf0jur7zeY0LRt8UvzbCwQv FO9C8NmIMXeGFYSpBzcdexYuDWUMSFegFPloaBVQUuA0zHcI9FuEOEbjQFPg3ABI4Ud/ ng61oqOsGOpDzJgc06svNz7UcpZySiYB0zx91zIWbC8bRRGi2SUvKhSL4HzS6I91krsg Be42tKYpeGxhsKS6KIe1VMq7A6CoYyAy9DKkPXGeHiChQesjsCZ52+eBkwgW8SJNDupc 11vz38sttV6BoxZb2a9Ib2oPseTgyFfd2ClqjAp2ML/45HTIDnw6nxHQyjw3jQ6xHGCd 3w== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2130.oracle.com with ESMTP id 2q8d2edrj4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 30 Jan 2019 23:14:09 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x0UNE3Wa014722 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 30 Jan 2019 23:14:03 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x0UNE2Qe002159; Wed, 30 Jan 2019 23:14:02 GMT Received: from [192.168.1.164] (/50.38.38.67) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 30 Jan 2019 15:14:02 -0800 Subject: Re: [LSF/MM TOPIC] NUMA remote THP vs NUMA local non-THP under MADV_HUGEPAGE To: Andrea Arcangeli , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Peter Xu , Blake Caldwell , Mike Rapoport , Michal Hocko , Mel Gorman , Vlastimil Babka , David Rientjes References: <20190129234058.GH31695@redhat.com> From: Mike Kravetz Message-ID: <609a56e4-c8b7-154f-dcbc-a12817fb22a0@oracle.com> Date: Wed, 30 Jan 2019 15:14:00 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190129234058.GH31695@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9152 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901300167 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/29/19 3:40 PM, Andrea Arcangeli wrote: > In addition to the above "NUMA remote THP vs NUMA local non-THP > tradeoff" topic, there are other developments in "userfaultfd" land that > are approaching merge readiness and that would be possible to provide a > short overview about: > > - Peter Xu made significant progress in finalizing the userfaultfd-WP > support over the last few months. That feature was planned from the > start and it will allow userland to do some new things that weren't > possible to achieve before. In addition to synchronously blocking > write faults to be resolved by an userland manager, it has also the > ability to obsolete the softdirty feature, because it can provide > the same information, but with O(1) complexity (as opposed of the > current softdirty O(N) complexity) similarly to what the Page > Modification Logging (PML) does in hardware for EPT write accesses. I would be interested in this topic as well. IIRC, Peter's patches do not address hugetlbfs support. I put together patches for this some time back. At the time, they worked as well as userfaultfd-WP support for normal base pages: not too well :). Once base page support is finalized, I suspect I will be involved in hugetlbfs support. -- Mike Kravetz