Re: [patch] CONFIG_ARCH_HAS_ATOMIC_UNSIGNED

[Christoph Lameter <christoph@lameter.com>]

On Fri, 17 Dec 2004, Andi Kleen wrote:

> On Fri, Dec 17, 2004 at 11:26:49AM -0800, Christoph Lameter wrote:
> > On Fri, 17 Dec 2004, Andi Kleen wrote:
> >
> > > > Put the order of the page there for compound pages instead of having that
> > > > in index?
> > >
> > > That would waste memory on the 64bit architectures that cannot tolerate
> > > 32bit atomic flags or on true 32bit architecture.
> >
> > Would be great to have 64 bit atomic support to fill this hole then.
>
> I think you lost me.   How would that help?

It would fill the hole on 64 bits if atomic_t would have the native word
size.

> To fill the hole you would need a 4 byte member with padding to move around,
> but there isn't one. You cannot also just add one because it would waste
> memory on 32bit archs and other 64bit archs.

There is no clean solution here but I just wanted to indicate what I would
like to see there if you want to use the space.

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