Re: vDSO vs. mm : problems with ppc vdso

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

> It should be done with some care - I suspect this will become *the*
> way in which we recognise a 64-bit mm and quite a bit of stuff will end up
> migrating to it.  We do need input from the various 64-bit people who have
> wrestled with these things.

Patch send, now let's get feedback ;)

> > I'll send the patch as a reply to this message.
> 
> Please copy linux-arch.

Did that.

> It's not ->mapping.  It's the fact that rmap only operates on pages which
> were found on the LRU.  If you don't add it to the LRU (and surely you do
> not) then no problem.

Ok.

> > Do you gus see any other case where my "special" vma & those kernel
> > pages in could be a problem ?
> 
> It sounds just like a sound card DMA buffer to me - that's a solved
> problem?  (Well, we keep unsolving it, but it's a relatively common
> pattern).

Might be ... though I though the later had VM_RESERVED or some similar
thing ... the trick with that vma is that i don't want any of these
things to allow for COW ... But yeah, it _looks_ like it will just work
(well... it appears to work so far anyway....)

Ben.


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