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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 AE195C433EF for ; Fri, 17 Sep 2021 20:57:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9147861074 for ; Fri, 17 Sep 2021 20:57:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244187AbhIQU7G (ORCPT ); Fri, 17 Sep 2021 16:59:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40360 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243182AbhIQU7C (ORCPT ); Fri, 17 Sep 2021 16:59:02 -0400 Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78F11C061574 for ; Fri, 17 Sep 2021 13:57:39 -0700 (PDT) Received: by mail-lf1-x12c.google.com with SMTP id y28so37128657lfb.0 for ; Fri, 17 Sep 2021 13:57:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov-name.20210112.gappssmtp.com; s=20210112; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=67xh3DmcBCGG+JgtqbeDJCPPKQGkafOab0xKjSMAcZA=; b=u/akYP8fIr5YX9VRdaEVJHYLd0LzSg00EpqVzqSwjM17eMmXVH4Vt7u55dJWa8zxUz NatucGpPSkbwSP36Zo8i0K+Tdv4MYgV0IB/C8Y1h8sVeFQfotq0CFjm9TF5uRAiK70nI e/zksaD+yvzB/to75omh0tw2JV236bxtkje3LEy0TifQzhUci5ZgWzfaeqgzT42/HlSj pcnjR+YcgyYj9PnIlzHCJsUWc5ZXad3h2vkzZ2KrVaIog3EvfIoCBxsAO0XU25Plpn6c iO6xIkbdg4nNSOTo5H8okK8vCt4llN9fyKMHGUuo3+1cwcSKm/oYiJ8xK7fgFfR8zrvk 3FdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=67xh3DmcBCGG+JgtqbeDJCPPKQGkafOab0xKjSMAcZA=; b=x8g3zAAdPDoocu5mw3T5eU6M//p6VPUxx8XA5la+IqesxMwavcR+KodTbof8gaUNjD xf5ALWx5W0a7hwJ2YIVjtjhWfznlj7+bFrkQDON4s/4uiXcdbUi6h96lTrWk9Z6y6HxR eT1O/P2nvd+zms1Pz4fwoFLx3sdO5B0Qk+9kq9xE1FtO84h4ZdZ+n+Kj7u7kk2WZ5gJo BVkoQ7apo90rTpUKB+5IDF+f098DD26qVVMYtz0W2z10jzQII6ly7iAg7DsygFs78gmZ +E35IltRHpCCfDzwuv5pIhgEGaXo2yrZWCA4MhrUiDn/SCu6TTjPBzVaM6SqhuNuJPOE 20yQ== X-Gm-Message-State: AOAM533ARkn2gl46qsseBFghaDeENIx+41yu4GbR+Sv6FhFRiYnOwgaX 2XNL4gloYLiDFPwnb/vE57IS9Q== X-Google-Smtp-Source: ABdhPJwzRLrammj1aWXBUhzKKoAy7/XvwF3BlowXLWGM9+36v2HXfgkOqKBJbRpX1iY07s9D7jGvhw== X-Received: by 2002:a2e:9903:: with SMTP id v3mr11033539lji.383.1631912257807; Fri, 17 Sep 2021 13:57:37 -0700 (PDT) Received: from box.localdomain ([86.57.175.117]) by smtp.gmail.com with ESMTPSA id y14sm607162lfk.237.2021.09.17.13.57.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 17 Sep 2021 13:57:36 -0700 (PDT) Received: by box.localdomain (Postfix, from userid 1000) id 4AFBE103041; Fri, 17 Sep 2021 23:57:35 +0300 (+03) Date: Fri, 17 Sep 2021 23:57:35 +0300 From: "Kirill A. Shutemov" To: Johannes Weiner Cc: Dave Chinner , "Darrick J. Wong" , Kent Overstreet , Matthew Wilcox , Linus Torvalds , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Christoph Hellwig , David Howells Subject: Re: Folio discussion recap Message-ID: <20210917205735.tistsacwwzkcdklx@box.shutemov.name> References: <20210916025854.GE34899@magnolia> <20210917052440.GJ1756565@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Sep 17, 2021 at 12:31:36PM -0400, Johannes Weiner wrote: > I didn't suggest to change what the folio currently already is for the > page cache. I asked to keep anon pages out of it (and in the future > potentially other random stuff that is using compound pages). It would mean that anon-THP cannot benefit from the work Willy did with folios. Anon-THP is the most active user of compound pages at the moment and it also suffers from the compound_head() plague. You ask to exclude anon-THP siting *possible* future benefits for pagecache. Sorry, but this doesn't sound fair to me. We already had similar experiment with PAGE_CACHE_SIZE. It was introduced with hope to have PAGE_CACHE_SIZE != PAGE_SIZE one day. It never happened and only caused confusion on the border between pagecache-specific code and generic code that handled both file and anon pages. If you want to limit usage of the new type to pagecache, the burden on you to prove that it is useful and not just a dead weight. -- Kirill A. Shutemov