Re: [patch] my mmu notifiers

Nick Piggin
2008-02-19T23:12:14Z

On Tue, Feb 19, 2008 at 02:58:51PM +0100, Andrea Arcangeli wrote:
> On Tue, Feb 19, 2008 at 09:43:57AM +0100, Nick Piggin wrote:
> > anything when changing the pte to be _more_ permissive, and I don't
>
> Note that in my patch the invalidate_pages in mprotect can be
> trivially switched to a mprotect_pages with proper params. This will
> prevent page faults completely in the secondary MMU (there will only
> be tlb misses after the tlb flush just like for the core linux pte),
> and it'll allow all the secondary MMU pte blocks (512/1024 at time
> with my PT lock design) to be updated to have proper permissions
> matching the core linux pte.

Sorry, I realise I still didn't get this through my head yet (and also
have not seen your patch recently). So I don't know exactly what you
are doing...

But why does _anybody_ (why does Christoph's patches) need to invalidate
when they are going to be more permissive? This should be done lazily by
the driver, I would have thought.