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Subject: [hwloc-devel] Memory affinity
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-02-28 11:51:03


Someone just made a fairly disturbing statement to me in an Open MPI bug ticket: if you bind some memory to a particular NUMA node, and that memory later gets paged out, then it loses its memory binding information -- meaning that it can effectively get paged back in at any physical location. Possibly even on a different NUMA node. (he said this in the context of the Linux kernel)

1. I have no reason to doubt this person, but was wondering if someone could confirm this (for Linux).

2. If it is true for Linux, can it also happen on other OSs? Or do other OSs track memory binding information when pages are swapped out?

-- 
Jeff Squyres
jsquyres_at_[hidden]
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