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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 2D03DC4338F for ; Fri, 6 Aug 2021 20:27:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0226B60FE7 for ; Fri, 6 Aug 2021 20:27:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244957AbhHFU2A (ORCPT ); Fri, 6 Aug 2021 16:28:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231823AbhHFU17 (ORCPT ); Fri, 6 Aug 2021 16:27:59 -0400 Received: from mail-qk1-x732.google.com (mail-qk1-x732.google.com [IPv6:2607:f8b0:4864:20::732]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAA84C0613CF for ; Fri, 6 Aug 2021 13:27:42 -0700 (PDT) Received: by mail-qk1-x732.google.com with SMTP id bl17so3661628qkb.12 for ; Fri, 06 Aug 2021 13:27:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=xzQzvEFEGoMscqJhOBHVn5b7he0gZrQNDSjY14VyYOw=; b=dq7DMYzv8T9XtjlGdkAS73Ksyq+eHKUjXuLdd3P7n+ajXOycUNW8tkIH668vRXCx02 MXcW+b0icMCY0tZtxYy/1GBKWpx5Gc+1f/x+aNCLJLQHPmkGspqJPdGm465A+TIZyTYN Ixrj8wgaTjgZh/ylqlnj2yAC331OykBbXlO90//0ffIuBpbi46VVgKzqBTP7CafqEXxA szhbGbw/wLrFO65JtQR2R9FHYk6J7ofxMO7mAY6ZEXAdIXsmQwPiTFX+N1xFRgZ3NijP Obs82xNyl84qdSI8a2hbywUBRzbuKyutrKH9or7Piu9TlcKx/X6SGZHnRb4lsOKPXv3E qLIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=xzQzvEFEGoMscqJhOBHVn5b7he0gZrQNDSjY14VyYOw=; b=rRXehqGr/627Zyx7ZsepcO7UPy8JLzssY/86x8r7ym98dxeLnB6FJ18TIjvXGfLD1/ b70CbJm4RjggQgKYrpdxLh9LMpRW4ECNKqMq4dzJBXcxoH0l4dx8B8DgrvNTJG5vNm9f iegIswrKxO1ITcc8K86xxs3yzO7yrPI45eujYC7RZWfezCjkljKiNL4iBmfvYhMuqmIR OGvxotkuiTY95nezg3XnacI7vdMaJyLG1QHfisrA2tB/GM/JePUJrnQz9AXeeCQ46oiH sFB2Ux337MdT/ONooA3RVEfKMpgO/K8UVuhQ8mp8ZxOAE/fQE+u0pAdfGpwJiLM2iiLk Wx8Q== X-Gm-Message-State: AOAM533/Tstm9HIlVv1driocXVAhZXvUfLe/VU1u+aTUlmz/cj0L5l8T 9NaKB9Z2cPU4Wr5aZMblDRDspA== X-Google-Smtp-Source: ABdhPJxyXNuZysU3Uk0rolv02J1uEhmrw1GH2+TaNt85aEW1RoW6U5Jrq9ThDt6LOt8Sy1R2Wq8iNA== X-Received: by 2002:a37:3c5:: with SMTP id 188mr9829169qkd.26.1628281661635; Fri, 06 Aug 2021 13:27:41 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id s14sm5438260qke.1.2021.08.06.13.27.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Aug 2021 13:27:41 -0700 (PDT) Date: Fri, 6 Aug 2021 13:27:27 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.anvils To: Zi Yan cc: Vlastimil Babka , David Hildenbrand , linux-mm@kvack.org, Matthew Wilcox , "Kirill A . Shutemov" , Mike Kravetz , Michal Hocko , John Hubbard , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 00/15] Make MAX_ORDER adjustable as a kernel boot time parameter. In-Reply-To: Message-ID: <6ae6cd92-3ff4-7ed3-b337-a4dfe33da1c@google.com> References: <20210805190253.2795604-1-zi.yan@sent.com> <0d374eed-cc52-a656-b338-1156782bdf7e@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 6 Aug 2021, Zi Yan wrote: > > In addition, I would like to share more detail on my plan on supporting 1GB PUD THP. > This patchset is the first step, enabling kernel to allocate 1GB pages, so that > user can get 1GB THPs from ZONE_NORMAL and ZONE_MOVABLE without using > alloc_contig_pages() or CMA allocator. The next step is to improve kernel memory > fragmentation handling for pages up to MAX_ORDER, since currently pageblock size > is still limited by memory section size. As a result, I will explore solutions > like having additional larger pageblocks (up to MAX_ORDER) to counter memory > fragmentation. I will discover what else needs to be solved as I gradually improve > 1GB PUD THP support. Sorry to be blunt, but let me state my opinion: 2MB THPs have given and continue to give us more than enough trouble. Complicating the kernel's mm further, just to allow 1GB THPs, seems a very bad tradeoff to me. I understand that it's an appealing personal project; but for the sake of of all the rest of us, please leave 1GB huge pages to hugetlbfs (until the day when we are all using 2MB base pages). Hugh