Re: [RFC] Slab allocators: Drop support for destructors

[Paul Mundt <lethal@linux-sh.org>]

On Thu, May 10, 2007 at 12:00:08PM -0700, Christoph Lameter wrote:
> As far as I can tell there is only a single slab destructor left (there 
> is currently another in i386 but its going to go as soon as Andi merges 
> i386s support for quicklists).
> 
> I wonder how difficult it would be to remove it? If we have no need for 
> destructors anymore then maybe we could remove destructor support from the 
> slab allocators? There is no point in checking for destructor uses in 
> the slab allocators if there are none.
> 
> Or are there valid reason to keep them around? It seems they were mainly 
> used for list management which required them to take a spinlock. Taking a 
> spinlock in a destructor is a bit risky since the slab allocators may run 
> the destructors anytime they decide a slab is no longer needed.
> 
> Or do we want to continue support destructors? If so why?
> 
[snip pmb stuff]

I'll take a look at tidying up the PMB slab, getting rid of the dtor
shouldn't be terribly painful. I simply opted to do the list management
there since others were doing it for the PGD slab cache at the time that
was written.