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 34665C43219 for ; Fri, 26 Apr 2019 05:33:46 +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 063212084F for ; Fri, 26 Apr 2019 05:33:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="WZrKiRGV" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 063212084F 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=0YEwMxDuLWb6Ftq5MLICmed8kaYHvko4n1iQ0I0XBlA=; b=WZrKiRGVOgn000 EtMDbn5KMCtb3j/mo7d6IOlB92grmZeKLoOjeEMLPX+7QMHe1IrC0p3mcGP3YELGp/qItmggasRU1 AUjZr6+PJMCLtx5Jj3dQSgDlIfGom6zBjoxZlAFqg5EKugEJf+oOAxBcb8rz9oObaKQPEfbe/6Qd8 FMfc32+XZKQNZF+rDWqrkLa3Zn+AG4luVxOxEYZXhqr6uigoZ90djR5jVsMJ9/80XSKqbIqO3unaB EiE0TVZpUtnn035EZ0hHL+07aM/iwssZOkRTsOoqrKu1zt0qLXy4fqXfuZLoW9XZu0gWxKuNCQw72 q8eoviRB3IEIjCDvB+nw==; 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 1hJtUX-0001Z5-BQ; Fri, 26 Apr 2019 05:33:45 +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 1hJtUT-0001YG-TT for linux-arm-kernel@lists.infradead.org; Fri, 26 Apr 2019 05:33:43 +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 EB6C6AD64; Fri, 26 Apr 2019 05:33:37 +0000 (UTC) Date: Fri, 26 Apr 2019 07:33:35 +0200 From: Michal Hocko To: Pavel Tatashin Subject: Re: [PATCH] arm64: configurable sparsemem section size Message-ID: <20190426053335.GD12337@dhcp22.suse.cz> References: <20190423203843.2898-1-pasha.tatashin@soleen.com> <20190425152550.GY12751@dhcp22.suse.cz> <20190425153138.GC25193@fuggles.cambridge.arm.com> <20190425154156.GZ12751@dhcp22.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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_223342_101074_2BF3A020 X-CRM114-Status: GOOD ( 15.34 ) 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: Takashi Iwai , Catalin Marinas , Dave Hansen , Will Deacon , Keith Busch , linux-mm , Yaowei Bai , Ross Zwisler , Sasha Levin , Dave Jiang , linux-nvdimm , Vishal L Verma , James Morris , "Huang, Ying" , Borislav Petkov , Tom Lendacky , Marc Zyngier , =?iso-8859-1?B?Suly9G1l?= Glisse , rppt@linux.vnet.ibm.com, Bjorn Helgaas , Dan Williams , Linux ARM , Ard Biesheuvel , sboyd@kernel.org, LKML , james.morse@arm.com, andrew.murray@arm.com, Andrew Morton , Fengguang Wu 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 Thu 25-04-19 13:57:25, Pavel Tatashin wrote: > > > I gave *vague* memories of running out of bits in the page flags if we > > > changed this, but that was a while back. If that's no longer the case, > > > then I'm open to changing the value, but I really don't want to expose > > > it as a Kconfig option as proposed in this patch. People won't have a > > > clue what to set and it doesn't help at all with the single-Image effort. > > > > Ohh, I absolutely agree about the config option part JFTR. 1GB section > > loos quite excessive. I am not really sure a standard arm64 memory > > layout looks though. > > I am now looking to use Dan's patches "mm: Sub-section memory hotplug > support" to solve this problem. I think this patch can be ignored. Even if the subsection memory hotplug is going to be used then the underlying question remains. If there is no real reason to use large memsections then it would be better to use smaller ones. -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel