Re: [PATCH] mmu notifiers #v2

Benjamin Herrenschmidt
2008-01-15T20:18:53Z

On Tue, 2008-01-15 at 13:44 +0100, Andrea Arcangeli wrote:
> On Mon, Jan 14, 2008 at 12:02:42PM -0800, Christoph Lameter wrote:
> > Hmmm... In most of the callsites we hold a writelock on mmap_sem right?
>
> Not in all, like Marcelo pointed out in kvm-devel, so the lowlevel
> locking can't relay on the VM locks.
>
> About your request to schedule in the mmu notifier methods this is not
> feasible right now, the notifier is often called with the pte
> spinlocks held. I wonder if you can simply post/queue an event like a
> softirq/pdflush.

Do you have cases where it's -not- called with the PTE lock held ?

Ben.