Re: [RFC] Demand faulting for large pages

[Andi Kleen]

On Fri, Aug 05, 2005 at 10:21:38AM -0500, Adam Litke wrote:
> Below is a patch to implement demand faulting for huge pages.  The main
> motivation for changing from prefaulting to demand faulting is so that
> huge page allocations can follow the NUMA API.  Currently, huge pages
> are allocated round-robin from all NUMA nodes.   

I think matching DEFAULT is better than having a different default for
huge pages than for small pages.

In general more programs are happy with local memory than remote memory.

Also it makes it consistent.

> 
> The default behavior in SLES9 for i386 is to use demand faulting with
> NUMA policy-aware allocations.  To my knowledge, this continues to work

Not sure what you're trying to say here. All allocations are NUMA policy aware.

> well in practice.  Thanks to consolidated hugetlb code, switching the
> behavior requires changing only one fault handler.  The bulk of the
> patch just moves the logic from hugelb_prefault() to
> hugetlb_pte_fault().

Are you sure you fixed get_user_pages to handle this properly? It doesn't
like it.

-Andi
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