DWARF data for 'struct slab' missing in linux-image-3.2.0-* debug deb

[Andy Whitcroft]

On Wed, Mar 06, 2013 at 02:26:49PM -0500, Steven Maresca wrote:
> In the linux-image-3.2.0-* debs from ddebs.ubuntu.com, I've noticed that
> 'struct slab' seems to be missing from type information provided by DWARF
> debug data.
> 
> Very easy to test:
> # shows the cfs_rq struct definition
> pahole -C cfs_rq /usr/lib/debug/boot/vmlinux-3.2.0-30-generic
> 
> # nothing
> pahole -C slab /usr/lib/debug/boot/vmlinux-3.2.0-30-generic
> 
> Is that an expected omission?  Another interesting thing to note is that
> 'struct array_cache' from mm/slab.c is similarly absent. Hundreds of other
> structure types are present as I'd normally expect, so it's an odd thing
> indeed.  (I've even tried multiple versions of pahole, readelf, objdump,
> etc. just to be sure).  It's worth saying that, even using SLUB, slab
> structures should still be in use.
> 
> I'm at a loss here. Any ideas?

As we use slub by default you would not expect to find things associated
with that, but with the slub version which uses different data
structures.

-apw