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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 8844EC433B4 for ; Tue, 18 May 2021 09:44:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CBA96610A8 for ; Tue, 18 May 2021 09:44:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CBA96610A8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2A5748D000A; Tue, 18 May 2021 05:44:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 255FF8D0001; Tue, 18 May 2021 05:44:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 129298D000A; Tue, 18 May 2021 05:44:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id D56BE8D0001 for ; Tue, 18 May 2021 05:44:37 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 5E8C2180AD838 for ; Tue, 18 May 2021 09:44:37 +0000 (UTC) X-FDA: 78153866994.31.2FE4A81 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) by imf25.hostedemail.com (Postfix) with ESMTP id 3ACFF6000104 for ; Tue, 18 May 2021 09:44:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=qfku/C/ExMDL6MsQW+4VS8Zyso0vOR9HeqIIBWxXDsQ=; b=aT7kvUX4ZgWiC2MZBAYrVFoRr Vph8pBGByIX51D+IxTJu2yu3C0QakB/JSogfuy+EbjG05Pn2CsvAqBplyiz4wIgj2x2O32yiEh0Dm e40eMr3CJ3yo3u2ePLEppfnQk3Ywgbj0DyOEdSsmqYc7Mhfd26GNE8XqygVja3GZUGO+BE8FfVpe0 trorCvz+swJuaa2kW6LJJx+zTLJDboFQn3eOSJ47YYswMvp5GzR/UZAWI0kHKiGMP/LuuEAye092v NY7Ga/oY+e1wUGJiCKZ97qNw7Bxg9W3lts01UyJeKv6fO6l2yzYRMBMB3tr9E/6umHhb4gllOPXOh gvcce1yhQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:44120) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1liwH7-0003z6-Be; Tue, 18 May 2021 10:44:29 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1liwH5-0007mk-5D; Tue, 18 May 2021 10:44:27 +0100 Date: Tue, 18 May 2021 10:44:27 +0100 From: "Russell King (Oracle)" To: Mike Rapoport Cc: linux-arm-kernel@lists.infradead.org, Andrew Morton , Kefeng Wang , Mike Rapoport , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 3/3] arm: extend pfn_valid to take into accound freed memory map alignment Message-ID: <20210518094427.GR12395@shell.armlinux.org.uk> References: <20210518090613.21519-1-rppt@kernel.org> <20210518090613.21519-4-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210518090613.21519-4-rppt@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Rspamd-Queue-Id: 3ACFF6000104 Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=armlinux.org.uk header.s=pandora-2019 header.b=aT7kvUX4; dmarc=pass (policy=none) header.from=armlinux.org.uk; spf=none (imf25.hostedemail.com: domain of linux@armlinux.org.uk has no SPF policy when checking 78.32.30.218) smtp.mailfrom=linux@armlinux.org.uk X-Rspamd-Server: rspam03 X-Stat-Signature: feqnxmfiaxj3wouweyktod7rt5t7q6c9 X-HE-Tag: 1621331074-832154 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000024, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, May 18, 2021 at 12:06:13PM +0300, Mike Rapoport wrote: > From: Mike Rapoport > > When unused memory map is freed the preserved part of the memory map is > extended to match pageblock boundaries because lots of core mm > functionality relies on homogeneity of the memory map within pageblock > boundaries. > > Since pfn_valid() is used to check whether there is a valid memory map > entry for a PFN, make it return true also for PFNs that have memory map > entries even if there is no actual memory populated there. I thought pfn_valid() was a particularly hot path... do we really want to be doing multiple lookups here? Is there no better solution? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!