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

From: Pekka Enberg
Date: Mon Mar 03 2008 - 16:37:20 EST


Hi,

Christoph Lameter wrote:
Well the guarantee can only be exploited if you would check the cacheline sizes and the object size from the code that creates the slab cache. Basically you would have to guestimate what the slab allocator is doing.

So the guarantee is basically meaningless. If the object is larger than a cacheline then this will never work.

Yes, I know that. That's why I am asking why this matters. If there's some sort of regression because SLUB does HWCACHE_ALIGN bit differently, we need to fix that. Not that it necessarily means we have to change HWCACHE_ALIGN but I am assuming Nick has some reason why he wants to introduce the SMP alignment flag.

Pekka
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/