Re: [PATCH/RFC 6/6] numa: slab: use numa_mem_id() for slab local memory node

Christoph Lameter
2009-11-20T16:00:45Z

On Fri, 13 Nov 2009, Lee Schermerhorn wrote:

> N.B.: incomplete. slab will need to handle node and memory hotplug
> that could change the value returned by numa_mem_id() for any given
> node. This will be addressed by a subsequent patch, if we decide to
> go this route.

It needs to be verified that this actually works. Locking is highly
depending on numa locality in slab. Can you run this under load with
lockdep? See also the lockdep issue that Pekka is dealing with right now.

>
> 2.6.32-rc5+mmotm-091101 no-patch this-patch
> no memoryless nodes [avg of 10]: 12.700 12.856 ~1.2%
> cpus all on memless nodes [20]: 261.530 27.700 ~10x speedup

This is due to memoryless nodes being able to use per cpu queues in slab
now. So far memoryless nodes always use fallback_alloc().