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 EC648EB64DC for ; Tue, 27 Jun 2023 07:16:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230073AbjF0HQI (ORCPT ); Tue, 27 Jun 2023 03:16:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229998AbjF0HQH (ORCPT ); Tue, 27 Jun 2023 03:16:07 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDD411BEF for ; Tue, 27 Jun 2023 00:14:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687850075; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N1scKhPxxz/YxysE64BuheSdyQmgV4XhiinPf6icWX8=; b=gLHtxCt7YxT7fD4RUMsMt5nkuqomgRGHLVnhkE5mtTO9G6qqlrV6MupV/chx6JnAHldSvj wk86egqixoIqEzSgzOQ0uzhhe50WyoLlDU0uUS0mQ8IJsOJB9b5honExYv+XEhLrorqKcT tv5LsStXpK5QhintwqeKkiF2P9peTmQ= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-458-zYEm0JHXNPiO-bDX046DhA-1; Tue, 27 Jun 2023 03:14:33 -0400 X-MC-Unique: zYEm0JHXNPiO-bDX046DhA-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-3f5df65fa35so17679235e9.3 for ; Tue, 27 Jun 2023 00:14:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687850072; x=1690442072; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=N1scKhPxxz/YxysE64BuheSdyQmgV4XhiinPf6icWX8=; b=WlXJBdiO4ZTtSxjt4iKJLNUoaAFstmzm8gNWQrBbM99oNvuXCMFyI8OAKetI+ebw/i tAW7VQCJhR5hB50Lji2jZ3/I3daixyuo8I2WJ4KBsr74MFSNwKkxXX6IiqbWj5wa68XA SgUABXBKU0MZAqN6xXHjT7T9EkkcWcXYVuoUqsfboseMgvpMshRA/L9FL4zCSqM0jGas Xg4KU6MAJhuNxAQazSbF49UeN9WCltQT9x4vB2ubqJFqSPnFvAM2NsvqSYtggJiuwUo0 0f76Xkv9aCX4J6MqsolijOfCGPV4DPxDQSbFmom9PpGjNb6TKBh6gDu1Hjn43XVVLIRg DKug== X-Gm-Message-State: AC+VfDxefgpeiTyX4WoLIUdOJFi+beY9I9oSzZmAqc+hA3bs51Tw9Wau /ZNykJySQpysFxYW8CJFFg6TFHjf3RHwNEWmhUuScdmy1imbPx4z3b7Q/qjAboYmXvOhUl0kQi8 tisb3mkpf2px4LG/88EzuoWViIqazRg== X-Received: by 2002:a05:600c:3655:b0:3fa:9d0f:f1e1 with SMTP id y21-20020a05600c365500b003fa9d0ff1e1mr2936771wmq.35.1687850072226; Tue, 27 Jun 2023 00:14:32 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6HIpOGvancvhac5jw2GR0kOhKc72MxDndtCuN9HZ1pSF+uaoBl/D52ddajPiSHV9uK1Eb9sw== X-Received: by 2002:a05:600c:3655:b0:3fa:9d0f:f1e1 with SMTP id y21-20020a05600c365500b003fa9d0ff1e1mr2936755wmq.35.1687850071891; Tue, 27 Jun 2023 00:14:31 -0700 (PDT) Received: from ?IPV6:2003:cb:c737:4900:68b3:e93b:e07a:558b? (p200300cbc737490068b3e93be07a558b.dip0.t-ipconnect.de. [2003:cb:c737:4900:68b3:e93b:e07a:558b]) by smtp.gmail.com with ESMTPSA id 21-20020a05600c22d500b003f96d10eafbsm9778433wmg.12.2023.06.27.00.14.30 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Jun 2023 00:14:31 -0700 (PDT) Message-ID: Date: Tue, 27 Jun 2023 09:14:29 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v6 00/33] Split ptdesc from struct page Content-Language: en-US To: Hugh Dickins , "Vishal Moola (Oracle)" Cc: Andrew Morton , Matthew Wilcox , linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-openrisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, Catalin Marinas , Huacai Chen , Geert Uytterhoeven , Thomas Bogendoerfer , Dinh Nguyen , Jonas Bonn , Claudio Imbrenda , Paul Walmsley , "David S. Miller" , Richard Weinberger , Yoshinori Sato , Dave Hansen , Arnd Bergmann , Christophe Leroy References: <20230627031431.29653-1-vishal.moola@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 27.06.23 06:44, Hugh Dickins wrote: > On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote: > >> The MM subsystem is trying to shrink struct page. This patchset >> introduces a memory descriptor for page table tracking - struct ptdesc. > ... >> 39 files changed, 686 insertions(+), 455 deletions(-) > > I don't see the point of this patchset: to me it is just obfuscation of > the present-day tight relationship between page table and struct page. > > Matthew already explained: > >> The intent is to get ptdescs to be dynamically allocated at some point >> in the ~2-3 years out future when we have finished the folio project ... > > So in a kindly mood, I'd say that this patchset is ahead of its time. > But I can certainly adapt to it, if everyone else sees some point to it. I share your thoughts, that code churn which will help eventually in the far, far future (not wanting to sound too pessimistic, but it's not going to be there tomorrow ;) ). However, if it's just the same as the other conversions we already did (e.g., struct slab), then I guess there is no reason to stop now -- the obfuscation already happened. ... or is there a difference regarding this conversion and the previous ones? -- Cheers, David / dhildenb