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Subject: Re: [hwloc-devel] Memory affinity
From: Jeff Squyres (jsquyres_at_[hidden])
Date: 2011-02-28 15:35:59


On Feb 28, 2011, at 3:31 PM, Brice Goglin wrote:

>>>> That would seem to imply that I should always hwloc_set_area_membind() if I want it to persist beyond any potential future swapping.
>
> The kernel only looks at the current virtual memory area policy. If you
> didn't call set_area_membind, the default policy is used. It doesn't
> care about the location of the old page before swap-out.

I'm not sure exactly what you mean here -- if I call hwloc_set_area_membind() to bind an area to numa node X, and then area pages get swapped out, then swapped back in, will be guaranteed to be swapped back in somewhere on numa node X? (I don't care if they're exactly the same physical page)

> It's similar to
> first-touch: use a local page as long as some pages are available there.

I'm not sure how to reconcile that statement with what I *think* your prior statement means... which probably means I don't understand your prior statement. :-)

-- 
Jeff Squyres
jsquyres_at_[hidden]
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