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=-8.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 37A37C432BE for ; Thu, 12 Aug 2021 01:37:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ACC0261058 for ; Thu, 12 Aug 2021 01:37:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org ACC0261058 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 23B918D0001; Wed, 11 Aug 2021 21:37:24 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1EB686B0071; Wed, 11 Aug 2021 21:37:24 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DA2E8D0001; Wed, 11 Aug 2021 21:37:24 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0018.hostedemail.com [216.40.44.18]) by kanga.kvack.org (Postfix) with ESMTP id E49C26B006C for ; Wed, 11 Aug 2021 21:37:23 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 78CE0181EE436 for ; Thu, 12 Aug 2021 01:37:23 +0000 (UTC) X-FDA: 78464715966.09.F460170 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf05.hostedemail.com (Postfix) with ESMTP id 2004B503D846 for ; Thu, 12 Aug 2021 01:37:23 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id D748560EE5; Thu, 12 Aug 2021 01:37:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1628732242; bh=3yliXKYml5z2kI731mSBDWtqWccUdEBlEAHRlw7CWUE=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=XSP8c6dj01Dk9xwmmCsAnKzMr571Sw7AQT6DrDOZ10jM+pq7m+CbeVj11JDdHOQ2C VFgaP3oaWAa2+t7CW4ieuADIZLAIQtsWckJFx+PTLLi+BffLv5xS3ZFvcDBTnyxct4 u/bUfqsNxdvVo6/YmLqhl1r5jrt9rZ1SrIg6BqgQD8EIQikxB6H3tG1Xg7dJf4vQXg oNsbfhIrYyYrTgAxI3zz2v1gni2bwmvWWr9QOBHAwo5rUdAotCas1aRMWCjXm+xxVD rUGcoXSY3mPJWYU6xYuufe8XfNGS1jcy0Rhi4S6zJKGLNEONxZFU2O/x/eaLOEhEov EcT6M9P/HJgbQ== Subject: Re: [PATCH 09/18] ARC: mm: non-functional code cleanup ahead of 3 levels To: Mike Rapoport Cc: linux-snps-arc@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Anshuman Khandual References: <20210811004258.138075-1-vgupta@kernel.org> <20210811004258.138075-10-vgupta@kernel.org> From: Vineet Gupta Message-ID: <7d022d55-c70b-b3ac-4f0b-1faa26c0d4bd@kernel.org> Date: Wed, 11 Aug 2021 18:37:19 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 2004B503D846 X-Stat-Signature: wfbywikaihsy49e6tqq5yan1784bd3hf Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=XSP8c6dj; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf05.hostedemail.com: domain of vgupta@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=vgupta@kernel.org X-HE-Tag: 1628732243-904352 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 8/11/21 5:31 AM, Mike Rapoport wrote: >> +/* >> + * For ARC, pgtable_t is not struct page *, but pte_t * (to avoid >> + * extraneous page_address() calculations) hence can't use >> + * use asm-generic/pgalloc.h which assumes it being struct page * >> + */ > Another reason to leave ARC without asm-generic/pgalloc.h was > __get_order_pte() that other arches don't have. > So this and pgtable_t aliased to pte_t * seemed to me too much to bother > then, but probably it's worth reconsidering with addition of 3rd and 4th > levels. I agree that savings of not havign page_address() might not be huge. However asm-generic/pgalloc.h only has pte allocation routines and all other allocation levels come from arch file Also for ARCv2, given the arbitrary address split and ensuing paging levels (as well as support for different page sizes) we will need to make sure that one page is enough to hold any level's paging using say BUILD_BUG_ON. In fact that should also be done for 3rd and 4th levels for sanity. -Vineet