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=-5.3 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 B8E51C433B4 for ; Mon, 10 May 2021 10:16:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3FBDE61424 for ; Mon, 10 May 2021 10:16:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3FBDE61424 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A62746B0070; Mon, 10 May 2021 06:16:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A11716B0071; Mon, 10 May 2021 06:16:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8B1BF6B0072; Mon, 10 May 2021 06:16:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0079.hostedemail.com [216.40.44.79]) by kanga.kvack.org (Postfix) with ESMTP id 6B11D6B0070 for ; Mon, 10 May 2021 06:16:02 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 27BA1180DC46D for ; Mon, 10 May 2021 10:16:02 +0000 (UTC) X-FDA: 78124915764.28.04C06E3 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf17.hostedemail.com (Postfix) with ESMTP id 82C1B407F8FA for ; Mon, 10 May 2021 10:15:56 +0000 (UTC) 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 CBCCA15BE; Mon, 10 May 2021 03:16:00 -0700 (PDT) Received: from [10.163.77.48] (unknown [10.163.77.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 190423F719; Mon, 10 May 2021 03:15:56 -0700 (PDT) Subject: Re: [PATCH] mm/thp: Make ARCH_ENABLE_SPLIT_PMD_PTLOCK dependent on PGTABLE_LEVELS > 2 To: Oscar Salvador Cc: Peter Zijlstra , linux-mm@kvack.org, akpm@linux-foundation.org, Heiko Carstens , Vasily Gorbik , Thomas Gleixner , Ingo Molnar , x86@kernel.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <1620621345-29176-1-git-send-email-anshuman.khandual@arm.com> <20210510085313.GB5618@worktop.programming.kicks-ass.net> <843e545a-ca0c-6a1e-2ab0-28ccca182400@arm.com> <20210510101006.GB22664@linux> From: Anshuman Khandual Message-ID: Date: Mon, 10 May 2021 15:46:41 +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: <20210510101006.GB22664@linux> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 Authentication-Results: imf17.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf17.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com X-Stat-Signature: akd4i59twwt6yc45rgmjz3iotoaotyzu X-Rspamd-Queue-Id: 82C1B407F8FA Received-SPF: none (arm.com>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=foss.arm.com; client-ip=217.140.110.172 X-HE-DKIM-Result: none/none X-HE-Tag: 1620641756-375162 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 5/10/21 3:40 PM, Oscar Salvador wrote: > On Mon, May 10, 2021 at 03:36:29PM +0530, Anshuman Khandual wrote: >> >> >> On 5/10/21 2:23 PM, Peter Zijlstra wrote: >>> On Mon, May 10, 2021 at 10:05:45AM +0530, Anshuman Khandual wrote: >>>> - select ARCH_ENABLE_SPLIT_PMD_PTLOCK if X86_64 || X86_PAE >>>> + select ARCH_ENABLE_SPLIT_PMD_PTLOCK if (PGTABLE_LEVELS > 2) && (X86_64 || X86_PAE) >>> >>> It's still very early on a Monday, but IIRC this new condition is >>> identical to the pre-existing one. >> >> Did not get it, could you please elaborate ? > > When using x86_PAE, you must have more than two pgtable levels, right? > And not speaking of x86_64. arch/x86/Kconfig.. config PGTABLE_LEVELS int default 5 if X86_5LEVEL default 4 if X86_64 default 3 if X86_PAE default 2 Both X86_PAE and X86_64 will always have page table levels > 2 ? But regardless, it might be still useful to assert (PGTABLE_LEVELS > 2) before selecting ARCH_ENABLE_SPLIT_PMD_PTLOCK.