Re: Page allocator: Single Zone optimizations

Christoph Lameter
2006-11-03T22:15:53Z

On Fri, 3 Nov 2006, Andrew Morton wrote:

> That's possibly useful if the cache has a destructor. If it has a
> constructor and no destructor then there's no point in locally caching the
> pages.
>
> But destructors are a bad idea: you dirty a cacheline, evict something else
> and then let the cacheline just sit there and go stale.

Right thats why I tried to avoid constructors and destructors for the new
slab design but it is important for RCU since the object must be in a
defined state even after a free. i386 arch code does some weird wizardry
with it. So I had to add a support layer.

> But I thought that slab once-upon-a-time retained caches of plain old free
> pages, not in any particular state. Maybe it did and maybe we did remove
> that.

Must have been before my time.