Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment

Christoph Lameter
2008-03-03T20:11:20Z

On Mon, 3 Mar 2008, Nick Piggin wrote:

> > If they are already not cache line aligned then we can make them as
> > dense as possible. That is what SLUB does.
>
> Because when you specify HWCACHE_ALIGN, it means that you want the object
> not to cross cacheline boundaries for at least cache_line_size() bytes.
> SLAB does this. SLUB does not without this patch.

HWCACHE_ALIGN means that you want the object to be aligned at
cacheline boundaries for optimization. Why does crossing cacheline
boundaries matter in this case?