Re: SLUB: Return ZERO_SIZE_PTR for kmalloc(0)
From: Christoph Lameter
Date: Sat Jun 02 2007 - 00:03:42 EST
On Fri, 1 Jun 2007, Andrew Morton wrote:
> > On Fri, 1 Jun 2007 18:37:46 -0700 (PDT) Christoph Lameter <clameter@xxxxxxx> wrote:
> >
> > +#define ZERO_SIZE_PTR ((void *)16)
>
> Jeremy's point was a good one. The kernel _does_ use address-comparison
> to determine object-inequality in an unknown but non-zero number of places.
>
> It is of course unlikely that this will occur in conjunction with zero-sized
> objects, but who knows?
The zero sized objects are always the same and have the same content of
nothingness. So the kernel would find that they are the same which they
indeed are. Why could this be a problem?
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