From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id A22D41A02AE for ; Fri, 6 Mar 2015 10:17:42 +1100 (AEDT) Received: from /spool/local by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 5 Mar 2015 16:17:40 -0700 Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id 3CFA93E4003E for ; Thu, 5 Mar 2015 16:17:39 -0700 (MST) Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t25NHdtg31588522 for ; Thu, 5 Mar 2015 16:17:39 -0700 Received: from d03av05.boulder.ibm.com (localhost [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t25NHcfx032223 for ; Thu, 5 Mar 2015 16:17:39 -0700 Date: Thu, 5 Mar 2015 15:17:37 -0800 From: Nishanth Aravamudan To: Michael Ellerman Subject: Re: [RFC PATCH] powerpc/numa: reset node_possible_map to only node_online_map Message-ID: <20150305231737.GC30570@linux.vnet.ibm.com> References: <20150305180549.GA29601@linux.vnet.ibm.com> <1425592132.13327.0.camel@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1425592132.13327.0.camel@ellerman.id.au> Cc: Raghavendra K T , Paul Mackerras , Anton Blanchard , David Rientjes , Tejun Heo , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 06.03.2015 [08:48:52 +1100], Michael Ellerman wrote: > On Thu, 2015-03-05 at 13:16 -0800, David Rientjes wrote: > > On Thu, 5 Mar 2015, Nishanth Aravamudan wrote: > > > > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > > > index 0257a7d659ef..24de29b3651b 100644 > > > --- a/arch/powerpc/mm/numa.c > > > +++ b/arch/powerpc/mm/numa.c > > > @@ -958,9 +958,17 @@ void __init initmem_init(void) > > > > > > memblock_dump_all(); > > > > > > + /* > > > + * zero out the possible nodes after we parse the device-tree, > > > + * so that we lower the maximum NUMA node ID to what is actually > > > + * present. > > > + */ > > > + nodes_clear(node_possible_map); > > > + > > > for_each_online_node(nid) { > > > unsigned long start_pfn, end_pfn; > > > > > > + node_set(nid, node_possible_map); > > > get_pfn_range_for_nid(nid, &start_pfn, &end_pfn); > > > setup_node_data(nid, start_pfn, end_pfn); > > > sparse_memory_present_with_active_regions(nid); > > > > This seems a bit strange, node_possible_map is supposed to be a superset > > of node_online_map and this loop is iterating over node_online_map to set > > nodes in node_possible_map. > > Yeah. Though at this point in boot I don't think it matters that the two maps > are out-of-sync temporarily. > > But it would simpler to just set the possible map to be the online > map. That would also maintain the invariant that the possible map is > always a superset of the online map. Yes, we could do that (see my reply to David just now). I didn't consider just setting the map directly, that would be clearer. I didn't want to post my nodes_and() version, because the cost of nodes_and seemed higher than nodes_clear & node_set appropriately. -Nish