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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DDFBC32771 for ; Wed, 28 Sep 2022 08:52:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233419AbiI1IwQ (ORCPT ); Wed, 28 Sep 2022 04:52:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34582 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232684AbiI1IwM (ORCPT ); Wed, 28 Sep 2022 04:52:12 -0400 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92820E28 for ; Wed, 28 Sep 2022 01:52:11 -0700 (PDT) Received: by mail-pj1-x102e.google.com with SMTP id x1-20020a17090ab00100b001fda21bbc90so1375075pjq.3 for ; Wed, 28 Sep 2022 01:52:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date; bh=YhKd/qqG3hYgCwHskWv+bTAHADkoBSPQyTs4xyUrQVI=; b=J/39CLLIHNbbdyLwo55aBZdPxMuVksxhxU12dvDDLDaKvLS6VPv7v931BU77Q1a1B6 xW/d7Ea1nvFFNO5PvVBhYufJpYccwEPApWWfHiWnfQbVV5X3WZZ+BhjXLxy3BqR9NTVE GCF9HQl6l805Y2WAq/Sg18KSEcQ75/UX+Qg81qIqqg+ANzt+xSsVlSYrJu48mG/tn0pn 4l+UIBhyu+9Ld/4aaLWSAAE3p7xKZTiuoav/lWw3a+h2BEocbnH6aosXQ2e0p1RJctBK qNqnZt3osniMHb5ksaZgTaIaPU51WQBXqR+xlhYFNrRDFITWd6BA4negrC6VG6EyIURM QVew== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=YhKd/qqG3hYgCwHskWv+bTAHADkoBSPQyTs4xyUrQVI=; b=nXJm2GOnuKMyeQJIwuChoK0LqMmdobCUpBvSZ7rlC5M0CMD6T49Cy3DB4osw6QC5PY eB3Dced7AV2VL6fux+zSbH/YGBgiGrUl/L8nt+6FOyaABf7iNYNwvQMlng9SjRzKJs5l IwDjshMNkNY0IiJZf54kynjHmx8uDfVX0dS4M0wVEpZClFnyugpldTYZha6asNwVLcCN I4TmhJ6o6DNLEIOg+XkJsqxQe8HKwZNCFhWIBXqo7bNKXwyFXg3iU+DUX/xxg8d/JUnx n7ix0x7vS0E3tH16By83a8jxW5IpewWmvXZeaMSiv1VRoNERVlu/UcL/9s1yZ3HycH/I /Fpg== X-Gm-Message-State: ACrzQf0J7FCaBWZvU8o/zv0W11NRZ8LPzNU7oNs+g/PTrpPWYbEhbV6V pbKZEA7+cQhYxD59ddqmJtM= X-Google-Smtp-Source: AMsMyM67XiMUXM9JXQrc/3ti18oFKIICmIsPNeCWVv8BA5XqIwNLPRe589oaCNlt/v5TcB+DTvIoBA== X-Received: by 2002:a17:90a:4588:b0:205:d605:8bcc with SMTP id v8-20020a17090a458800b00205d6058bccmr9146720pjg.205.1664355131012; Wed, 28 Sep 2022 01:52:11 -0700 (PDT) Received: from zhienlin-MBP ([140.121.198.208]) by smtp.gmail.com with ESMTPSA id k4-20020a17090a3e8400b002030d596ff7sm964068pjc.37.2022.09.28.01.52.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Sep 2022 01:52:10 -0700 (PDT) Date: Wed, 28 Sep 2022 16:52:02 +0800 From: Chih-En Lin To: John Hubbard Cc: Nadav Amit , Andrew Morton , Qi Zheng , David Hildenbrand , Matthew Wilcox , Christophe Leroy , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Luis Chamberlain , Kees Cook , Iurii Zaikin , Vlastimil Babka , William Kucharski , "Kirill A . Shutemov" , Peter Xu , Suren Baghdasaryan , Arnd Bergmann , Tong Tiangen , Pasha Tatashin , Li kunyu , Anshuman Khandual , Minchan Kim , Yang Shi , Song Liu , Miaohe Lin , Thomas Gleixner , Sebastian Andrzej Siewior , Andy Lutomirski , Fenghua Yu , Dinglan Peng , Pedro Fonseca , Jim Huang , Huichun Feng Subject: Re: [RFC PATCH v2 9/9] mm: Introduce Copy-On-Write PTE table Message-ID: References: <20220927162957.270460-1-shiyn.lin@gmail.com> <20220927162957.270460-10-shiyn.lin@gmail.com> <3D21021E-490F-4FE0-9C75-BB3A46A66A26@vmware.com> <10594124-b6b7-d202-d90b-72ac9d8bc9dc@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <10594124-b6b7-d202-d90b-72ac9d8bc9dc@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 27, 2022 at 02:26:19PM -0700, John Hubbard wrote: > On 9/27/22 12:53, Chih-En Lin wrote: > > I'm not familiar with THP right now. But we have a plan for looking > > at it to see what will happen with COW PTE. > > Currently, I can only say that I prefer to avoid involving the behavior > > of huge-page/THP. If there are any ideas here please tell us. > > > In order to be considered at all, this would have to at least behave > correctly in the presence of THP and hugetlbfs, IMHO. Those are no > longer niche features. > To make sure it will work well with them. During fork() and page fault, we put the mechanism after the hug-page/THP to make it doesn't mess up. It may have corner cases that I didn't handle. I will keep looking at it. Thanks, Chih-En lin