[ofa-general] Re: [PATCH 01 of 12] Core of mmu notifiers

Christoph Lameter
2008-04-28T20:34:11Z

On Sun, 27 Apr 2008, Andrea Arcangeli wrote:

> Talking about post 2.6.26: the refcount with rcu in the anon-vma
> conversion seems unnecessary and may explain part of the AIM slowdown
> too. The rest looks ok and probably we should switch the code to a
> compile-time decision between rwlock and rwsem (so obsoleting the
> current spinlock).

You are going to take a semphore in an rcu section? Guess you did not
activate all debugging options while testing? I was not aware that you can
take a sleeping lock from a non preemptible context.