From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f181.google.com (mail-wi0-f181.google.com [209.85.212.181]) by kanga.kvack.org (Postfix) with ESMTP id A48B86B0031 for ; Wed, 19 Feb 2014 04:20:02 -0500 (EST) Received: by mail-wi0-f181.google.com with SMTP id hi5so336124wib.2 for ; Wed, 19 Feb 2014 01:20:02 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id bs18si14726433wib.18.2014.02.19.01.20.00 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 19 Feb 2014 01:20:01 -0800 (PST) Date: Wed, 19 Feb 2014 10:19:59 +0100 From: Michal Hocko 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: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Anton Blanchard , Benjamin Herrenschmidt , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org, LKML 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, 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