Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760039Ab3EAWa7 (ORCPT ); Wed, 1 May 2013 18:30:59 -0400 Received: from mail-da0-f51.google.com ([209.85.210.51]:50829 "EHLO mail-da0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757497Ab3EAWaz (ORCPT ); Wed, 1 May 2013 18:30:55 -0400 Date: Wed, 1 May 2013 15:30:52 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Cody P Schafer cc: Andrew Morton , Linux MM , LKML Subject: Re: [PATCH 4/4] memory_hotplug: use pgdat_resize_lock() when updating node_present_pages In-Reply-To: <1367446635-12856-5-git-send-email-cody@linux.vnet.ibm.com> Message-ID: References: <1367446635-12856-1-git-send-email-cody@linux.vnet.ibm.com> <1367446635-12856-5-git-send-email-cody@linux.vnet.ibm.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1278 Lines: 33 On Wed, 1 May 2013, Cody P Schafer wrote: > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index a221fac..0bdca10 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -915,6 +915,7 @@ static void node_states_set_node(int node, struct memory_notify *arg) > > int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type) > { > + unsigned long flags; > unsigned long onlined_pages = 0; > struct zone *zone; > int need_zonelists_rebuild = 0; > @@ -993,7 +994,11 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ > > zone->managed_pages += onlined_pages; > zone->present_pages += onlined_pages; > + > + pgdat_resize_lock(zone->zone_pgdat, &flags); > zone->zone_pgdat->node_present_pages += onlined_pages; > + pgdat_resize_unlock(zone->zone_pgdat, &flags); > + > if (onlined_pages) { > node_states_set_node(zone_to_nid(zone), &arg); > if (need_zonelists_rebuild) Why? You can't get a partial read of a word-sized data structure. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/