Re: [BUG] slab debug vs. L1 alignement

[Andrew Morton]

Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> Currently, when enabling slab debugging, we lose the property of
> having the objects aligned on a cache line size.
> 
> This is, imho, an error, especially if GFP_DMA is passed. Such an
> object _must_ be cache alined (and it's size rounded to a multiple
> of the cache line size).

Well the theory is that SLAB_HWCACHE_ALIGN is advisory and
SLAB_MUST_HWCACHE_ALIGN is compulsory.

You're looking for compulsory alignment on the generic kmalloc() slab
pools, so we're a bit screwed.

I guess the redzoning would need to be taught to always pad by a full
cacheline.

-
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/