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=-2.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_HIGH,UNPARSEABLE_RELAY,USER_AGENT_NEOMUTT 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 47968C5CFEB for ; Mon, 9 Jul 2018 17:21:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0230020864 for ; Mon, 9 Jul 2018 17:21:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="g7K2M8Ld" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0230020864 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.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 S933928AbeGIRVJ (ORCPT ); Mon, 9 Jul 2018 13:21:09 -0400 Received: from aserp2130.oracle.com ([141.146.126.79]:46180 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933479AbeGIRVG (ORCPT ); Mon, 9 Jul 2018 13:21:06 -0400 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 w69HJIF2075517; Mon, 9 Jul 2018 17:20:38 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=cdz6Fc8Y45/mytGQB11dZk7enR4eI9uNICfJV2mGcO0=; b=g7K2M8LdvUDHEilqS7tQEr5X1lzLKiBsVyusqjOfxcrTyMbiN4d3MBlPubg7i8XDNwq6 ggQqhnIC1UcdRfHyyPb5Nlyl8EMe64YQQuAC8QLxUP7AHwEq1pOEwDFHYg2YxDRw8aWB VLJixt6OhCKQTdGxbOvo7E12/lIFJHAO5yH+S/d7/lqpp4s+ZvevBk/IGVC1PqdcYsNg GzPnsPc+jd2NMHRett9WVoE4PWMhYHBtyHtpuBrDg6zru7Inh+eTXGGa2KaxnfuZG+he fzdyx8o4m7aXMP441Ji4YvCSNrQp4R5RFFvA0YR2uadwhHbar8IAwsy8Zkv1aLIWJ8QF pA== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2130.oracle.com with ESMTP id 2k2p75n6nv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 09 Jul 2018 17:20:38 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w69HKb8p019800 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 Jul 2018 17:20:37 GMT Received: from abhmp0011.oracle.com (abhmp0011.oracle.com [141.146.116.17]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w69HKZqe014970; Mon, 9 Jul 2018 17:20:35 GMT Received: from ca-dmjordan1.us.oracle.com (/10.211.9.48) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 09 Jul 2018 10:20:35 -0700 Date: Mon, 9 Jul 2018 10:20:37 -0700 From: Daniel Jordan To: "Huang, Ying" Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" , Andrea Arcangeli , Michal Hocko , Johannes Weiner , Shaohua Li , Hugh Dickins , Minchan Kim , Rik van Riel , Dave Hansen , Naoya Horiguchi , Zi Yan Subject: Re: [PATCH -mm -v4 14/21] mm, cgroup, THP, swap: Support to move swap account for PMD swap mapping Message-ID: <20180709172037.254zyuadep2hj5po@ca-dmjordan1.us.oracle.com> References: <20180622035151.6676-1-ying.huang@intel.com> <20180622035151.6676-15-ying.huang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180622035151.6676-15-ying.huang@intel.com> User-Agent: NeoMutt/20180323-268-5a959c X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8948 signatures=668705 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807090197 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 22, 2018 at 11:51:44AM +0800, Huang, Ying wrote: > Because there is no way to prevent a huge swap cluster from being > split except when it has SWAP_HAS_CACHE flag set. What about making get_mctgt_type_thp take the cluster lock? That function would be the first lock_cluster user outside of swapfile.c, but it would serialize with split_swap_cluster. > It is possible for > the huge swap cluster to be split and the charge for the swap slots > inside to be changed, after we check the PMD swap mapping and the huge > swap cluster before we commit the charge moving. But the race window > is so small, that we will just ignore the race. Moving the charges is a slow path, so can't we just be correct here and not leak?