From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f69.google.com (mail-pa0-f69.google.com [209.85.220.69]) by kanga.kvack.org (Postfix) with ESMTP id A8D8A6B0283 for ; Tue, 25 Oct 2016 11:55:18 -0400 (EDT) Received: by mail-pa0-f69.google.com with SMTP id hm5so27167578pac.4 for ; Tue, 25 Oct 2016 08:55:18 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id h191si21344990pgc.323.2016.10.25.08.55.17 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 25 Oct 2016 08:55:17 -0700 (PDT) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u9PFs56M090653 for ; Tue, 25 Oct 2016 11:55:17 -0400 Received: from e36.co.us.ibm.com (e36.co.us.ibm.com [32.97.110.154]) by mx0b-001b2d01.pphosted.com with ESMTP id 26a8dnk4t7-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 25 Oct 2016 11:55:17 -0400 Received: from localhost by e36.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 25 Oct 2016 09:55:15 -0600 Date: Tue, 25 Oct 2016 10:55:07 -0500 From: Reza Arbab Subject: Re: [PATCH v4 4/5] mm: make processing of movable_node arch-specific References: <1475778995-1420-1-git-send-email-arbab@linux.vnet.ibm.com> <1475778995-1420-5-git-send-email-arbab@linux.vnet.ibm.com> <235f2d20-cf84-08df-1fb4-08ee258fdc52@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Message-Id: <20161025155507.37kv5akdlgo6m2be@arbab-laptop.austin.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Balbir Singh Cc: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Rob Herring , Frank Rowand , Andrew Morton , Bharata B Rao , Nathan Fontenot , Stewart Smith , Alistair Popple , "Aneesh Kumar K.V" , Tang Chen , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org, linux-mm@kvack.org On Tue, Oct 25, 2016 at 11:15:40PM +1100, Balbir Singh wrote: >After the ack, I realized there were some more checks needed, IOW >questions for you :) Hey! No takebacks! The short answer is that neither of these is a concern. Longer; if you use "movable_node", x86 can identify these nodes at boot. They call memblock_mark_hotplug() while parsing the SRAT. Then, when the zones are initialized, those markings are used to determine ZONE_MOVABLE. We have no analog of this SRAT information, so our movable nodes can only be created post boot, by hotplugging and explicitly onlining with online_movable. >1. Have you checked to see if our memblock allocations spill >over to probably hotpluggable nodes? Since our nodes don't exist at boot, we don't have that short window before the zones are drawn where the node has normal memory, and a kernel allocation might occur within. >2. Shouldn't we be marking nodes discovered as movable via >memblock_mark_hotplug()? Again, this early boot marking mechanism only applies to movable_node. -- 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