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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 36B19C433DF for ; Mon, 6 Jul 2020 11:21:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F28452073E for ; Mon, 6 Jul 2020 11:21:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F28452073E Authentication-Results: mail.kernel.org; dmarc=none (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 740476B0008; Mon, 6 Jul 2020 07:21:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6F0F66B000A; Mon, 6 Jul 2020 07:21:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6076C6B000C; Mon, 6 Jul 2020 07:21:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0038.hostedemail.com [216.40.44.38]) by kanga.kvack.org (Postfix) with ESMTP id 49F376B0008 for ; Mon, 6 Jul 2020 07:21:23 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E10511EE6 for ; Mon, 6 Jul 2020 11:21:22 +0000 (UTC) X-FDA: 77007410004.05.drink95_1514d8726eab Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id BEF0A18014A1B for ; Mon, 6 Jul 2020 11:21:22 +0000 (UTC) X-HE-Tag: drink95_1514d8726eab X-Filterd-Recvd-Size: 2760 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Mon, 6 Jul 2020 11:21:22 +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 36A2EC0A; Mon, 6 Jul 2020 04:21:21 -0700 (PDT) Received: from gaia (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7420D3F68F; Mon, 6 Jul 2020 04:21:19 -0700 (PDT) Date: Mon, 6 Jul 2020 12:21:13 +0100 From: Catalin Marinas To: David Hildenbrand Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Andrew Morton , Steven Price Subject: Re: [PATCH v6 06/26] mm: Add PG_arch_2 page flag Message-ID: <20200706112057.GA6432@gaia> References: <20200703153718.16973-1-catalin.marinas@arm.com> <20200703153718.16973-7-catalin.marinas@arm.com> <27fe044a-8315-5394-575e-8f763696b0cd@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <27fe044a-8315-5394-575e-8f763696b0cd@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: BEF0A18014A1B X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 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 Mon, Jul 06, 2020 at 10:24:04AM +0200, David Hildenbrand wrote: > On 03.07.20 17:36, Catalin Marinas wrote: > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > > index 6be1aa559b1e..276140c94f4a 100644 > > --- a/include/linux/page-flags.h > > +++ b/include/linux/page-flags.h > > @@ -135,6 +135,9 @@ enum pageflags { > > #if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT) > > PG_young, > > PG_idle, > > +#endif > > +#ifdef CONFIG_64BIT > > + PG_arch_2, > > #endif > > __NR_PAGEFLAGS, > > People are usually *very* picky when it comes to new page flags. It > somewhat concerns me that we bump up __NR_PAGEFLAGS for any 64bit arch. > That feels wrong. It was guarded by a specific config option initially but the comments suggested that it could be dropped for 64-bit architectures: https://lore.kernel.org/linux-arm-kernel/20200624113307.6165b3db2404c9d37b870a90@linux-foundation.org/ The page flags is indeed a pretty limited resource as it also includes the sparsemem section, node and zone fields. However, on 64-bit this should be fine (the sparsemem section is gone with vmemmap support). -- Catalin