Re: Stable cvs version for 2.4

Jasmine Strong
2002-09-04T14:49:33Z

On Wed, 4 Sep 2002, David Woodhouse wrote:

> At a gratuitous extra 4 bytes per object, that's... ok, well it's only
> wasting 32KiB which is less than I expected, but it still annoys me.

Is there nowhere that's not a pointer that you can stuff it?

> > (Architectures that don't always use word-aligned pointers include
> > m68k and ARM Thumb.)
>
> Even when we're allocating from the slab and the object in question is a
> structure of size which is an even number?

If you can ensure that the region you are allocating from is word-aligned,
that the structures within it are always word aligned, and the code will
never run on architectures with weird addressing schemes, fine.

> Even so, I'd assume that we care even _more_ about that 32KiB on uCLinux, so

Yes, I'd agree, but...

> maybe it's worth adding 1 byte of padding to the structure there and
> manually aligning the pointer after allocating, or something. We only need
> 1 bit, after all. Or we could use the _top_ bit on uCLinux, perhaps?

Depends on the architecture, again. Problem is that treating pointers as
non-opaque objects will necessarily limit portability.

Jas.