Re: [mm][RFC][PATCH 0/11] mm accessor updates.

Ingo Molnar
2009-12-18T05:18:14Z

* Christoph Lameter <cl@linux-foundation.org> wrote:

> On Thu, 17 Dec 2009, Peter Zijlstra wrote:
>
> > > That is why I think that the accessors are a good first step.
> >
> > They're not, they're daft, they operate on a global resource mm_struct,
> > that's the whole problem, giving it a different name isn't going to solve
> > anything.
>
> It is not about naming. The accessors hide the locking mechanism for
> mmap_sem. Then you can change the locking in a central place.
>
> The locking may even become configurable later. Maybe an embedded solution
> will want the existing scheme but dual quad socket may want a distributed
> reference counter to avoid bouncing cachelines on faults.

Hiding the locking is pretty much the worst design decision one can make.

Ingo