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Date: Thu, 9 Apr 2015 15:37:09 -0700
From: Nishanth Aravamudan <nacc@linux.vnet.ibm.com>
To: Brice Goglin <Brice.Goglin@inria.fr>
Subject: Re: Topology updates and NUMA-level sched domains
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Cc: Boqun Feng <boqun.feng@linux.vnet.ibm.com>,
 Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
 Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org,
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On 08.04.2015 [12:32:01 +0200], Brice Goglin wrote:
> Le 07/04/2015 21:41, Peter Zijlstra a écrit :
> > No, that's very much not the same. Even if it were dealing with hotplug
> > it would still assume the cpu to return to the same node.
> >
> > But mostly people do not even bother to handle hotplug.
> >
> 
> You said userspace assumes the cpu<->node relation is a boot-time fixed
> one, and hotplug breaks this. How do you expect userspace to handle
> hotplug? Is there a convenient way to be notified when a CPU (or memory)
> is unplugged?

There is some mention of "User Space Notification" in cpu-hotplug.txt,
but no idea if it's current.

-Nish