Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752796AbaBSJUJ (ORCPT ); Wed, 19 Feb 2014 04:20:09 -0500 Received: from cantor2.suse.de ([195.135.220.15]:52733 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205AbaBSJUB (ORCPT ); Wed, 19 Feb 2014 04:20:01 -0500 Date: Wed, 19 Feb 2014 10:19:59 +0100 From: Michal Hocko To: David Rientjes Cc: Anton Blanchard , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, LKML Subject: Re: ppc: RECLAIM_DISTANCE 10? Message-ID: <20140219091959.GD14783@dhcp22.suse.cz> References: <20140218090658.GA28130@dhcp22.suse.cz> <20140219081644.GA14783@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 00:20:21, David Rientjes wrote: > On Wed, 19 Feb 2014, Michal Hocko wrote: > > > > I strongly suspect that the patch is correct since powerpc node distances > > > are different than the architectures you're talking about and get doubled > > > for every NUMA domain that the hardware supports. > > > > Even if the units of the distance is different on PPC should every NUMA > > machine have zone_reclaim enabled? That doesn't right to me. > > > > In my experience on powerpc it's very correct, there's typically a > significant latency in remote access and we don't have the benefit of a > SLIT that actually defines the locality between proximity domains like we > do on other architectures. Interesting. So is the PPC NUMA basically about local vs. very distant? Should REMOTE_DISTANCE reflect that as well? Or can we have distance < REMOTE_DISTANCE and it would still make sense to have zone_reclaim enabled? [...] Thanks! -- 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/