Re: Q: explicit alignment control for the slab allocator

[Manfred Spraul <manfred@colorfullife.com>]

"David S. Miller" wrote:
> 
> Manfred, why are you changing the cache alignment to
> SMP_CACHE_BYTES?  If you read the original SLAB papers
> and other documents, the code intends to color the L1
> cache not the L2 or subsidiary caches.
>
I'll undo that change.

I only found this comment in the source file:

> /* For performance, all the general caches are L1 aligned.
>  * This should be particularly beneficial on SMP boxes, as it
>  * eliminates "false sharing".
>  * Note for systems short on memory removing the alignment will
>  * allow tighter packing of the smaller caches. */

To avoid false sharing we would need SMP_CACHE_BYTES aligning, not L1
aligning.

--
	Manfred