From: Michal Hocko <mhocko@suse.cz>
To: David Rientjes <rientjes@google.com>
Cc: linuxppc-dev@lists.ozlabs.org, Anton Blanchard <anton@samba.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: ppc: RECLAIM_DISTANCE 10?
Date: Wed, 19 Feb 2014 10:19:59 +0100 [thread overview]
Message-ID: <20140219091959.GD14783@dhcp22.suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.02.1402190017480.7280@chino.kir.corp.google.com>
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
next prev parent reply other threads:[~2014-02-19 9:20 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-18 9:06 ppc: RECLAIM_DISTANCE 10? Michal Hocko
2014-02-18 22:27 ` David Rientjes
2014-02-19 8:16 ` Michal Hocko
2014-02-19 8:20 ` David Rientjes
2014-02-19 9:19 ` Michal Hocko [this message]
2014-02-19 21:45 ` David Rientjes
2014-02-18 23:34 ` Nishanth Aravamudan
2014-02-18 23:58 ` Nishanth Aravamudan
2014-02-19 0:40 ` Nishanth Aravamudan
2014-02-19 1:43 ` David Rientjes
2014-02-19 8:33 ` Michal Hocko
2014-02-19 16:24 ` Nishanth Aravamudan
2014-02-19 16:33 ` Nishanth Aravamudan
2014-02-20 9:55 ` Michal Hocko
2014-02-19 8:23 ` Michal Hocko
2014-02-19 16:26 ` Nishanth Aravamudan
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