From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 491806B0274 for ; Wed, 26 Oct 2016 06:53:02 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id c84so4733471pfb.1 for ; Wed, 26 Oct 2016 03:53:02 -0700 (PDT) Received: from ozlabs.org (ozlabs.org. [103.22.144.67]) by mx.google.com with ESMTPS id qj8si1629655pac.114.2016.10.26.03.53.00 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Oct 2016 03:53:01 -0700 (PDT) From: Michael Ellerman Subject: Re: [PATCH v4 4/5] mm: make processing of movable_node arch-specific In-Reply-To: <20161026004929.h6v54dhehk4yvmwm@arbab-vm> 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> <20161025155507.37kv5akdlgo6m2be@arbab-laptop.austin.ibm.com> <112504e9-561d-e0da-7a40-73996c678b56@gmail.com> <20161026004929.h6v54dhehk4yvmwm@arbab-vm> Date: Wed, 26 Oct 2016 21:52:53 +1100 Message-ID: <87vawfwfei.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Reza Arbab , Balbir Singh Cc: 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 Reza Arbab writes: > On Wed, Oct 26, 2016 at 09:34:18AM +1100, Balbir Singh wrote: >>I still believe we need your changes, I was wondering if we've tested >>it against normal memory nodes and checked if any memblock >>allocations end up there. Michael showed me some memblock >>allocations on node 1 of a two node machine with movable_node > > The movable_node option is x86-only. Both of those nodes contain normal > memory, so allocations on both are allowed. > >>> 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. >> >>Is this true for all of system memory as well or only for nodes >>hotplugged later? > > As far as I know, power has nothing like the SRAT that tells us, at > boot, which memory is hotpluggable. On pseries we have the ibm,dynamic-memory device tree property, which can contain ranges of memory that are not yet "assigned to the partition" - ie. can be hotplugged later. So in general that statement is not true. But I think you're focused on bare-metal, in which case you might be right. But that doesn't mean we couldn't have a similar property, if skiboot/hostboot knew what the ranges of memory were going to be. cheers -- 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