From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f45.google.com (mail-pa0-f45.google.com [209.85.220.45]) by kanga.kvack.org (Postfix) with ESMTP id 298A66B0031 for ; Wed, 19 Feb 2014 16:45:17 -0500 (EST) Received: by mail-pa0-f45.google.com with SMTP id lf10so957051pab.18 for ; Wed, 19 Feb 2014 13:45:16 -0800 (PST) Received: from mail-pb0-x22f.google.com (mail-pb0-x22f.google.com [2607:f8b0:400e:c01::22f]) by mx.google.com with ESMTPS id nd12si1114447pab.330.2014.02.19.13.45.15 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Wed, 19 Feb 2014 13:45:16 -0800 (PST) Received: by mail-pb0-f47.google.com with SMTP id rp16so964933pbb.20 for ; Wed, 19 Feb 2014 13:45:15 -0800 (PST) Date: Wed, 19 Feb 2014 13:45:14 -0800 (PST) From: David Rientjes Subject: Re: ppc: RECLAIM_DISTANCE 10? In-Reply-To: <20140219091959.GD14783@dhcp22.suse.cz> Message-ID: References: <20140218090658.GA28130@dhcp22.suse.cz> <20140219081644.GA14783@dhcp22.suse.cz> <20140219091959.GD14783@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Anton Blanchard , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, LKML On Wed, 19 Feb 2014, Michal Hocko wrote: > Interesting. So is the PPC NUMA basically about local vs. very distant? The point is that it's impossible to tell how distant they are from one NUMA domain to the next NUMA domain. > 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? > Ppc doesn't want to allocate in a different NUMA domain unless required, the latency of a remote access is too high. Everything that isn't in the same domain has a distance >10 and is setup as 2^(domain hops) * 10. We don't have the ability like with a SLIT to define remote nodes to have local latency vs remote or costly latency so the safe setting is a RECLAIM_DISTANCE of 10. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org