Re: NUMA node information for pages

From: David Rientjes
Date: Tue Apr 01 2014 - 00:29:49 EST


On Mon, 31 Mar 2014, Naoya Horiguchi wrote:

> > I might be missing something but I couldn't find a way to use the
> > pagemap information to then look up the NUMA node the respective page is
> > located on. Especially when analyzing anomalities this is really
> > useful. The /proc/kpageflags and /proc/kpagecount files don't have that
> > information.
> >
> > If this is correct, could the attached patch be considered? It's really
> > simple and follows the same line as the kpageflags file.
>
> The information about "pfn-node" mapping seldom (or never) changes after boot,
> so it seems better to me that adding a new interface somewhere under
> /sys/devices/system/node/nodeN which shows pfn range of a given node.

If that's the direction we're going, I'd much prefer just the physical
start and end addresses be exported rather than pfn so we don't need to do
getpagesize() in userspace.
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