Re: [PATCH 20/25] mm: Simplify anon_vma refcounts

From: Peter Zijlstra
Date: Tue Jan 25 2011 - 15:30:54 EST

On Wed, 2011-01-26 at 06:16 +1000, Linus Torvalds wrote:
> On Wed, Jan 26, 2011 at 3:31 AM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> >
> > This patch changes the anon_vma refcount to be 0 when the object is
> > free. It does this by adding 1 ref to being in use in the anon_vma
> > structure (iow. the anon_vma->head list is not empty).
> Why is this patch part of this series, rather than being an
> independent patch before the whole series?
> I think this part of the series is the only total no-brainer, ie we
> should have done this from the beginning. The preemptability stuff I'm
> more nervous about (performance issues? semantic differences?)

It relies on patch 19, which moves the anon_vma refcount out from under

If however you like it, I can move 19 and this patch up to the start and
have that go your way soon.
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