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=-5.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 CAA6DC433E6 for ; Fri, 5 Feb 2021 08:30:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9273B64F9C for ; Fri, 5 Feb 2021 08:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229621AbhBEIae (ORCPT ); Fri, 5 Feb 2021 03:30:34 -0500 Received: from foss.arm.com ([217.140.110.172]:51880 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229466AbhBEIac (ORCPT ); Fri, 5 Feb 2021 03:30:32 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EB71331B; Fri, 5 Feb 2021 00:29:45 -0800 (PST) Received: from [10.163.93.198] (unknown [10.163.93.198]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 9F6733F73B; Fri, 5 Feb 2021 00:29:42 -0800 (PST) Subject: Re: [RFC 2/3] arm64/hugetlb: Enable HUGETLB_PAGE_SIZE_VARIABLE To: David Hildenbrand , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, akpm@linux-foundation.org Cc: Will Deacon , Robin Murphy , Marek Szyprowski , Christoph Hellwig , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <1612422084-30429-1-git-send-email-anshuman.khandual@arm.com> <1612422084-30429-3-git-send-email-anshuman.khandual@arm.com> <616578ec-8a61-ce0a-a467-50915b3a9967@redhat.com> From: Anshuman Khandual Message-ID: Date: Fri, 5 Feb 2021 14:00:11 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <616578ec-8a61-ce0a-a467-50915b3a9967@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/5/21 1:50 PM, David Hildenbrand wrote: > On 04.02.21 08:01, Anshuman Khandual wrote: >> MAX_ORDER which invariably depends on FORCE_MAX_ZONEORDER can be a variable >> for a given page size, depending on whether TRANSPARENT_HUGEPAGE is enabled >> or not. In certain page size and THP combinations HUGETLB_PAGE_ORDER can be >> greater than MAX_ORDER, making it unusable as pageblock_order. > > Just so I understand correctly, this does not imply that we have THP that exceed the pageblock size / MAX_ORDER size, correct? Correct. MAX_ORDER gets incremented when THP is enabled. config FORCE_MAX_ZONEORDER int default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) default "11"