[ofa-general] Re: [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges

[Andrea Arcangeli]

On Wed, Feb 27, 2008 at 02:23:29PM -0800, Christoph Lameter wrote:
> How would that work? You rely on the pte locking. Thus calls are all in an 

I don't rely on the pte locking in #v7, exactly to satisfy GRU
(so far purely theoretical) performance complains.

> atomic context. I think we need a general scheme that allows sleeping when 

Calls are still in atomic context until we change the i_mmap_lock to a
mutex under a CONFIG_XPMEM, or unless we boost mm_users, drop the lock
and restart the loop at every different mm. In any case those changes
should be under CONFIG_XPMEM IMHO given desktop users definitely don't
need this (regular non-blocking mmu notifiers in my patch are all what
a desktop user need as far as I can tell).

> references are invalidates. Even the GRU has performance issues when using 
> the KVM patch.

GRU will perform the same with #v7 or V8.