Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752711AbaBTJzk (ORCPT ); Thu, 20 Feb 2014 04:55:40 -0500 Received: from cantor2.suse.de ([195.135.220.15]:48002 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751560AbaBTJzh (ORCPT ); Thu, 20 Feb 2014 04:55:37 -0500 Date: Thu, 20 Feb 2014 10:55:34 +0100 From: Michal Hocko To: Nishanth Aravamudan Cc: David Rientjes , linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, Anton Blanchard , LKML Subject: Re: ppc: RECLAIM_DISTANCE 10? Message-ID: <20140220095534.GC12451@dhcp22.suse.cz> References: <20140218090658.GA28130@dhcp22.suse.cz> <20140218233404.GB10844@linux.vnet.ibm.com> <20140218235800.GC10844@linux.vnet.ibm.com> <20140219162438.GB27108@linux.vnet.ibm.com> <20140219163345.GD27108@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140219163345.GD27108@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 19-02-14 08:33:45, Nishanth Aravamudan wrote: > On 19.02.2014 [08:24:38 -0800], Nishanth Aravamudan wrote: > > On 18.02.2014 [17:43:38 -0800], David Rientjes wrote: > > > On Tue, 18 Feb 2014, Nishanth Aravamudan wrote: > > > > > > > How about the following? > > > > > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > > > index 5de4337..1a0eced 100644 > > > > --- a/mm/page_alloc.c > > > > +++ b/mm/page_alloc.c > > > > @@ -1854,7 +1854,8 @@ static void __paginginit init_zone_allows_reclaim(int nid) > > > > int i; > > > > > > > > for_each_online_node(i) > > > > - if (node_distance(nid, i) <= RECLAIM_DISTANCE) > > > > + if (node_distance(nid, i) <= RECLAIM_DISTANCE || > > > > + !NODE_DATA(i)->node_present_pages) > > > > node_set(i, NODE_DATA(nid)->reclaim_nodes); > > > > else > > > > zone_reclaim_mode = 1; > > > > > > [ I changed the above from NODE_DATA(nid) -> NODE_DATA(i) as you caught > > > so we're looking at the right code. ] > > > > > > That can't be right, it would allow reclaiming from a memoryless node. I > > > think what you want is > > > > Gah, you're right. > > > > > for_each_online_node(i) { > > > if (!node_present_pages(i)) > > > continue; > > > if (node_distance(nid, i) <= RECLAIM_DISTANCE) { > > > node_set(i, NODE_DATA(nid)->reclaim_nodes); > > > continue; > > > } > > > /* Always try to reclaim locally */ > > > zone_reclaim_mode = 1; > > > } > > > > > > but we really should be able to do for_each_node_state(i, N_MEMORY) here > > > and memoryless nodes should already be excluded from that mask. > > > > Yep, I found that afterwards, which simplifies the logic. I'll add this > > to my series :) > > In looking at the code, I am wondering about the following: > > init_zone_allows_reclaim() is called for each nid from > free_area_init_node(). Which means that calculate_node_totalpages for > other "later" nids and check_for_memory() [which sets up the N_MEMORY > nodemask] hasn't been called yet. > > So, would it make sense to pull up the > /* Any memory on that node */ > if (pgdat->node_present_pages) > node_set_state(nid, N_MEMORY); > check_for_memory(pgdat, nid); > into free_area_init_node()? Dunno, but it shouldn't be needed because nodes are set N_MEMORY earlier in early_calculate_totalpages as mentioned in other email. -- Michal Hocko SUSE Labs -- 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/