Re: [PATCH] mmu notifiers #v8

Christoph Lameter
2008-03-03T19:01:35Z

On Mon, 3 Mar 2008, Nick Piggin wrote:

> I'm still not completely happy with this. I had a very quick look
> at the GRU driver, but I don't see why it can't be implemented
> more like the regular TLB model, and have TLB insertions depend on
> the linux pte, and do invalidates _after_ restricting permissions
> to the pte.
>
> Ie. I'd still like to get rid of invalidate_range_begin, and get
> rid of invalidate calls from places where permissions are relaxed.

Isnt this more a job for paravirt ops if it is so tightly bound to page
tables? Are we not adding another similar API?

> If we can agree on the API, then I don't see any reason why it can't
> go into 2.6.25, unless someome wants more time to review it (but
> 2.6.25 release should be quite far away still so there should be quite
> a bit of time).

API still has rcu issues and the example given for making things sleepable
is only working for the aging callback. The most important callback is for
try_to_unmao and page_mkclean. This means the API is still not generic
enough and likely not extendable as needed in its present form.