Re: returning non-ram via ->nopage, was Re: [patch] mspec driver for 2.6.12-rc2-mm3

[William Lee Irwin III]

On Tue, Apr 26, 2005 at 06:14:02PM -0400, Jes Sorensen wrote:
> Having the page allocations and drop ins on a first touch basis is
> consistent with what is done for cached memory and seems a pretty
> reasonable approach to me. Sure it isn't particularly pretty to use
> the ->nopage approach, nobody disagrees with you there, but what is
> the alternative?
> Is the problem more an issue of the ugliness of allocating a page
> just to return it to the nopage handler or the fact that we're trying
> to make the allocations node local?
> If you have any suggestions for how to do this differently, then I'm
> all ears.
> Cheers,
> Jes
> PS: Thanks to Robin Holt for providing more info on MPI application
> behavior than I ever wanted to know ;-)

This and several other issues all fall down when instead of ->nopage(),
the vma's fault handling method takes a vma, a virtual address, and
an access type, and returns a VM_FAULT_* code. Yes, I remember how I
got heavily criticized the last time I wrote/suggested/whatever this.


-- wli
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