From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f71.google.com (mail-lf0-f71.google.com [209.85.215.71]) by kanga.kvack.org (Postfix) with ESMTP id 49DFC6B025E for ; Wed, 21 Sep 2016 01:45:17 -0400 (EDT) Received: by mail-lf0-f71.google.com with SMTP id y6so1088663lff.0 for ; Tue, 20 Sep 2016 22:45:17 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id a9si28376577wje.165.2016.09.20.22.45.15 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 20 Sep 2016 22:45:15 -0700 (PDT) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u8L5f7h7027828 for ; Wed, 21 Sep 2016 01:45:14 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0b-001b2d01.pphosted.com with ESMTP id 25kjkwmf54-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 21 Sep 2016 01:45:14 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 20 Sep 2016 23:45:12 -0600 Date: Wed, 21 Sep 2016 00:45:01 -0500 From: Reza Arbab Subject: Re: [PATCH v2 3/3] mm: enable CONFIG_MOVABLE_NODE on powerpc References: <1473883618-14998-1-git-send-email-arbab@linux.vnet.ibm.com> <1473883618-14998-4-git-send-email-arbab@linux.vnet.ibm.com> <87h99cxv00.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <87h99cxv00.fsf@linux.vnet.ibm.com> Message-Id: <20160921054500.lrqktzjqjhuzewqg@arbab-laptop> Sender: owner-linux-mm@kvack.org List-ID: To: "Aneesh Kumar K.V" Cc: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Rob Herring , Frank Rowand , Jonathan Corbet , Andrew Morton , Bharata B Rao , Nathan Fontenot , Stewart Smith , Alistair Popple , Balbir Singh , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org, linux-mm@kvack.org On Mon, Sep 19, 2016 at 11:59:35AM +0530, Aneesh Kumar K.V wrote: >Movable node also does. > memblock_set_bottom_up(true); >What is the impact of that. Do we need changes equivalent to that ? Also >where are we marking the nodes which can be hotplugged, ie where do we >do memblock_mark_hotplug() ? These are related to the mechanism x86 uses to create movable nodes at boot. The SRAT is parsed to mark any hotplug memory. That marking is used later when initializing ZONE_MOVABLE for each node. [1] The bottom-up allocation is due to a timing issue [2]. There is a window where kernel memory may be allocated before the SRAT is parsed. Any bottom-up allocations done during that time will likely be in the same (nonmovable) node as the kernel image. On power, I don't think we have a heuristic equivalent to that SRAT memory hotplug info. So, we'll be limited to dynamically adding movable nodes after boot. 1. http://events.linuxfoundation.org/sites/events/files/lcjp13_chen.pdf 2. commit 79442ed189ac ("mm/memblock.c: introduce bottom-up allocation mode") -- Reza Arbab -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org