Hi,This reminds me a previous attempt of removing SLAB_HWCACHE_ALIGN
On Mon, Mar 3, 2008 at 3:46 PM, Nick Piggin <npiggin@xxxxxxx> wrote:
> Maybe we need to use three flags to separate the meanings ?
>
> SLAB_HINT_SMP_ALIGN
> SLAB_HINT_HWCACHE_ALIGN
> SLAB_HWCACHE_ALIGN /* strong requirement that two objects dont share a
> cache line */
Possibly, but I'm beginning to prefer that strong requirements should
request the explicit alignment (they can even use cache_line_size() after
Pekka's patch to make it generic). I don't like how the name implies
that you get a guarantee, however I guess in practice people are using it
more as a hint (or because they vaguely hope it makes their code run
faster :))
At least historically SLAB_HWCACHE_ALIGN has been just a hint,
although slab tries very hard to satisfy it (see the comments in
mm/slab.c). Why do we need stronger guarantees than that, btw?