Re: Stable cvs version for 2.4

David Woodhouse
2002-09-04T14:38:49Z

jasmine@hex.linuxgrrls.org said:
> Yes. uCLinux, anyway. Pointers should always be treated as opaque
> unless you have a *really* good reason not to.

I have 8000 reasons not to:

# grep node_frag /proc/slabinfo
jffs2_node_frag 8028 8064 28 64 64 1

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.

> (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?

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

--
dwmw2