Re: Fast LKM symbol resolution with SysV ELH hash table

[Greg KH <greg@kroah.com>]

On Mon, Oct 19, 2009 at 01:45:20PM +0200, Carmelo Amoroso wrote:
> Just a few other notes. The current implementation I did based on SysV
> has a drawback that is not backward compatible, so you cannot use old
> modules with a kernel with the option enabled due to changes on struct
> kernel_symbol.

Why would this be a problem?  Whenever making a kernel config change,
you should be able to rebuild everything, as lots of other configuration
options are that way.

> Anyway I've just figured out how to change it to remove this limitation.
> I need some time to review these patches.  Further, the newer
> implementation based on GNU hash which we are working on right now,
> will not require the extra .undef.hash ELF sections because hash
> values are already embedded into the GNU hash table, with a reduction
> in terms of footprint.

Footprint in the memory for the loaded module, or just in the footprint
for the module on the disk?

I'd be interested in seeing your patches when you have something that
works for the current Linus kernel tree.

thanks,

greg k-h