Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932331AbbFVEsu (ORCPT ); Mon, 22 Jun 2015 00:48:50 -0400 Received: from mail-vn0-f41.google.com ([209.85.216.41]:33698 "EHLO mail-vn0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751420AbbFVEso (ORCPT ); Mon, 22 Jun 2015 00:48:44 -0400 MIME-Version: 1.0 Date: Mon, 22 Jun 2015 10:18:43 +0530 Message-ID: Subject: powerpc,numa: Memory hotplug to memory-less nodes ? From: Bharata B Rao To: linuxppc-dev , "linux-kernel@vger.kernel.org" Cc: Nathan Fontenot , Paul Mackerras , Anton Blanchard Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 645 Lines: 20 Hi, While developing memory hotplug support in QEMU for PoweKVM, I realized that guest kernel has specific checks to prevent hot addition of memory to a memory-less node. I am referring to arch/powerpc/mm/numa.c:hot_add_scn_to_nid() which has explicit checks to ensure that it returns a nid that has some some memory (NODE_DATA(nid)->node_spanned_pages) even when user wants to hotplug to a node that currently has zero memory. Is this limitation by design ? Regards, Bharata. -- http://raobharata.wordpress.com/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/