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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 E2ACAC43219 for ; Thu, 25 Apr 2019 15:26:05 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1875A20644 for ; Thu, 25 Apr 2019 15:26:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DupEkD51" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1875A20644 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=fHi2uiTGzQQOAQ7Pe+5Y6dytlgkwcEFELss34WbXDXA=; b=DupEkD51lSWj/8 lOrbwkVndfUg26HSjZdgEG7APlgkxNpgqqiAW23zmFZ+iQSOhby/RJnYYHW2EOktntx08Xg/ciHbi KFe5s/7dyLs8jM6dt68+nrRvNUw/XfGq6/0GXd7onD+ucUf4JVluzISWyoSFQhUShgxXj2cuDXII+ vNZ01UttBgY2aZ95jAj12kI4zIObOe27BzFh350RyAMgQA4JLT5YtNCwAElqkpZi7dUYk0AwM5tUN jWgs0T7P3KUhvZZTJO3H5G7z/LhcAp+iDZ0IS9EshE02hsWeXqwPZu1gD3e5/gNh5rTJ6UTptbVIT aC2qW97A5GXZuCaKvejQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1hJgG5-0003nX-6A; Thu, 25 Apr 2019 15:25:57 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hJgG2-0003mt-It for linux-arm-kernel@lists.infradead.org; Thu, 25 Apr 2019 15:25:55 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6F7B5AF26; Thu, 25 Apr 2019 15:25:52 +0000 (UTC) Date: Thu, 25 Apr 2019 17:25:50 +0200 From: Michal Hocko To: Pavel Tatashin Subject: Re: [PATCH] arm64: configurable sparsemem section size Message-ID: <20190425152550.GY12751@dhcp22.suse.cz> References: <20190423203843.2898-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190423203843.2898-1-pasha.tatashin@soleen.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190425_082554_770862_F9DE935C X-CRM114-Status: GOOD ( 12.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: tiwai@suse.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, will.deacon@arm.com, keith.busch@intel.com, linux-mm@kvack.org, baiyaowei@cmss.chinamobile.com, zwisler@kernel.org, sashal@kernel.org, dave.jiang@intel.com, linux-nvdimm@lists.01.org, vishal.l.verma@intel.com, jmorris@namei.org, ying.huang@intel.com, bp@suse.de, thomas.lendacky@amd.com, marc.zyngier@arm.com, jglisse@redhat.com, rppt@linux.vnet.ibm.com, bhelgaas@google.com, dan.j.williams@intel.com, linux-arm-kernel@lists.infradead.org, ard.biesheuvel@linaro.org, sboyd@kernel.org, linux-kernel@vger.kernel.org, james.morse@arm.com, andrew.murray@arm.com, akpm@linux-foundation.org, fengguang.wu@intel.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue 23-04-19 16:38:43, Pavel Tatashin wrote: > sparsemem section size determines the maximum size and alignment that > is allowed to offline/online memory block. The bigger the size the less > the clutter in /sys/devices/system/memory/*. On the other hand, however, > there is less flexability in what granules of memory can be added and > removed. > > Recently, it was enabled in Linux to hotadd persistent memory that > can be either real NV device, or reserved from regular System RAM > and has identity of devdax. > > The problem is that because ARM64's section size is 1G, and devdax must > have 2M label section, the first 1G is always missed when device is > attached, because it is not 1G aligned. > > Allow, better flexibility by making section size configurable. Is there any inherent reason (64k page size?) that enforces such a large memsection? -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel