Re: PTE access rules & abstraction

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

On Thu, 2008-09-25 at 00:55 +0100, Hugh Dickins wrote:
> 
> Whyever not the latter?  Jeremy seems to have gifted that to you,
> for precisely such a purpose.

Yeah. Not that I don't quite understand what the point of the
start/modify/commit thing the way it's currently used in mprotect since
we are doing the whole transaction for a single PTE change, ie how does
that help with hypervisors vs. a single ptep_modify_protection() for
example is beyond me :-)

When I think about transactions, I think about starting a transaction,
changing a -bunch- of PTEs, then commiting... Essentially I see the PTE
lock thing as being a transaction.

Cheers,
Ben.

> Hugh
> 
> p.s. I surely agree with you over the name ptep_get_and_clear_full():
> horrid, even more confusing than the tlb->fullmm from which it derives
> its name.  I expect I'd agree with you over a lot more too, but
> please, bugfixes first.

Sure.