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 50CC3C433ED for ; Tue, 18 May 2021 09:44:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3257761353 for ; Tue, 18 May 2021 09:44:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243411AbhERJpz (ORCPT ); Tue, 18 May 2021 05:45:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243020AbhERJpy (ORCPT ); Tue, 18 May 2021 05:45:54 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A81EFC061573 for ; Tue, 18 May 2021 02:44:36 -0700 (PDT) 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) Sender: Russell King (Oracle) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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!