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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 7CA02C433E4 for ; Fri, 17 Jul 2020 09:59:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54B852070E for ; Fri, 17 Jul 2020 09:59:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="vBH9iXY1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726070AbgGQJ75 (ORCPT ); Fri, 17 Jul 2020 05:59:57 -0400 Received: from smtp-fw-2101.amazon.com ([72.21.196.25]:21577 "EHLO smtp-fw-2101.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbgGQJ75 (ORCPT ); Fri, 17 Jul 2020 05:59:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1594979996; x=1626515996; h=from:to:cc:subject:date:message-id:in-reply-to: mime-version; bh=9vaHmuMsNN0kIp0YqM12N3y5Zy+mAtWNYvcQ8zisUCM=; b=vBH9iXY1ugHiuN2VMVXO4uF7xlqNvWERnBrc9eWc9g5udeDFHnhT9aON dfGZPwNbYFS5c3Ml9+4aLWJT8HTJ4Y2b6rrw7+dn1wz6hOy4ZPgTwuDSu sTBFDc+x7Hk9U4btwG9CnESa1oZqh8Cul2NaIUbJBKDI5u+Yt+EOV+qsc E=; IronPort-SDR: 6PDhm+xE4JDdLX39G/DZKH1Kn+CU+lfhtanLL/IjlririC28jO/snZL2Q7aMTFPxbVd11ZQ3CH iRLZFTHsFQXA== X-IronPort-AV: E=Sophos;i="5.75,362,1589241600"; d="scan'208";a="42377858" Received: from iad12-co-svc-p1-lb1-vlan2.amazon.com (HELO email-inbound-relay-1e-97fdccfd.us-east-1.amazon.com) ([10.43.8.2]) by smtp-border-fw-out-2101.iad2.amazon.com with ESMTP; 17 Jul 2020 09:59:55 +0000 Received: from EX13MTAUEA002.ant.amazon.com (iad55-ws-svc-p15-lb9-vlan2.iad.amazon.com [10.40.159.162]) by email-inbound-relay-1e-97fdccfd.us-east-1.amazon.com (Postfix) with ESMTPS id 52A8CA11D6; Fri, 17 Jul 2020 09:59:45 +0000 (UTC) Received: from EX13D31EUA004.ant.amazon.com (10.43.165.161) by EX13MTAUEA002.ant.amazon.com (10.43.61.77) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 17 Jul 2020 09:59:44 +0000 Received: from u886c93fd17d25d.ant.amazon.com (10.43.160.26) by EX13D31EUA004.ant.amazon.com (10.43.165.161) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Fri, 17 Jul 2020 09:59:26 +0000 From: SeongJae Park To: SeongJae Park CC: Mike Rapoport , , "SeongJae Park" , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: Re: Re: Re: [PATCH v18 01/14] mm/page_ext: Export lookup_page_ext() to GPL modules Date: Fri, 17 Jul 2020 11:59:10 +0200 Message-ID: <20200717095910.23550-1-sjpark@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200713173805.31923-1-sjpark@amazon.com> (raw) MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.43.160.26] X-ClientProxiedBy: EX13D14UWC003.ant.amazon.com (10.43.162.19) To EX13D31EUA004.ant.amazon.com (10.43.165.161) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, 13 Jul 2020 19:38:05 +0200 SeongJae Park wrote: > On Mon, 13 Jul 2020 20:19:09 +0300 Mike Rapoport wrote: > > > On Mon, Jul 13, 2020 at 02:21:43PM +0200, SeongJae Park wrote: > > > On Mon, 13 Jul 2020 15:08:42 +0300 Mike Rapoport wrote: > > > > > > > Hi, > > > > > > > > On Mon, Jul 13, 2020 at 10:41:31AM +0200, SeongJae Park wrote: > > > > > From: SeongJae Park > > > > > > > > > > This commit exports 'lookup_page_ext()' to GPL modules. It will be used > > > > > by DAMON in following commit for the implementation of the region based > > > > > sampling. > > > > > > > > Maybe I'm missing something, but why is DAMON a module? > > > > > > I made it loadable just for easier adoption from downstream kernels. I could > > > drop the module build support if asked. > > > > Well, exporting core mm symbols to modules should be considred very > > carefully. > > Agreed. I will drop the module support from the next spin. > > > > > Why lookup_page_ext() is required for DAMON? It is not used anywhere in > > this patchset. > > It's indirectly used. In the 6th patch, DAMON uses 'set_page_young()' to not > interfere with other PTE Accessed bit users. And, 'set_page_young()' uses > 'lookup_page_ext()' if !CONFIG_64BIT. That's why I exported it. This also means that it would make no sense if !64BIT && !PAGE_EXTENSION. In the next spin, I will update the DAMON Kconfig to select PAGE_EXTENSION if !64BIT, as same to that of IDLE_PAGE_TRACKING. Thanks, SeongJae Park