[PATCH v2] powerpc: align DTL buffer to AMS boundary

[Michael Ellerman]

On Wed, 2011-04-13 at 15:33 -0700, Nishanth Aravamudan wrote:
> PAPR specifies that DTL buffers can not cross AMS environments (aka CMO
> in the PAPR) and can not cross a memory entitlement granule boundary
> (4k). This is found in section 14.11.3.2 H_REGISTER_VPA of the PAPR.
> kmalloc does not guarantee an alignment of the allocation, though,
> beyond 8 bytes (at least in my understanding). Over-allocate and align
> the resulting address.

You can specify alignment by creating your own kmem_cache, ie.
kmem_cache_create().

Obviously there will be some overhead to create the cache structure, but
I'd think it will be less than 4k * NR_CPUs.

cheers



-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20110414/d31ff770/attachment.pgp>