Re: vDSO vs. mm : problems with ppc vdso

Benjamin Herrenschmidt
2006-02-28T06:30:19Z

> 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.