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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 9B20CECE589 for ; Thu, 3 Oct 2019 09:53:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 792D9217D7 for ; Thu, 3 Oct 2019 09:53:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729654AbfJCJxE (ORCPT ); Thu, 3 Oct 2019 05:53:04 -0400 Received: from foss.arm.com ([217.140.110.172]:39940 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729601AbfJCJxA (ORCPT ); Thu, 3 Oct 2019 05:53:00 -0400 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 5B9D91000; Thu, 3 Oct 2019 02:52:59 -0700 (PDT) Received: from [10.162.40.180] (p8cg001049571a15.blr.arm.com [10.162.40.180]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 84E9F3F739; Thu, 3 Oct 2019 02:52:56 -0700 (PDT) Subject: Re: [PATCH] mm/page_alloc: Add a reason for reserved pages in has_unmovable_pages() To: Qian Cai Cc: linux-mm@kvack.org, Andrew Morton , Michal Hocko , Vlastimil Babka , Oscar Salvador , Mel Gorman , Mike Rapoport , Dan Williams , Pavel Tatashin , linux-kernel@vger.kernel.org References: <1570090257-25001-1-git-send-email-anshuman.khandual@arm.com> <7FA7CBE1-E0A9-40E2-B3CA-0896F6D491E5@lca.pw> <37b43978-5652-576c-8990-451e751b7c67@arm.com> From: Anshuman Khandual Message-ID: Date: Thu, 3 Oct 2019 15:23:18 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <37b43978-5652-576c-8990-451e751b7c67@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/03/2019 03:02 PM, Anshuman Khandual wrote: > > On 10/03/2019 02:35 PM, Qian Cai wrote: >> >>> On Oct 3, 2019, at 4:10 AM, Anshuman Khandual wrote: >>> >>> Having unmovable pages on a given pageblock should be reported correctly >>> when required with REPORT_FAILURE flag. But there can be a scenario where a >>> reserved page in the page block will get reported as a generic "unmovable" >>> reason code. Instead this should be changed to a more appropriate reason >>> code like "Reserved page". >> Isn’t this redundant as it dumps the flags in dump_page() anyway? > Even though page flags does contain reserved bit information, the problem > is that we are explicitly printing the reason for this page dump. In this > case it is caused by the fact that it is a reserved page. > > page dumped because: > > The proposed change makes it explicit that the dump is caused because a > non movable page with reserved bit set. It also helps in differentiating > between reserved bit condition and the last one "if (found > count)" Instead, will it better to rename the reason codes as 1. "Unmovable (CMA)" 2. "Unmovable (Reserved)" 3. "Unmovable (Private/non-LRU)"