Re: [patch 2/2] fs: buffer: move allocation failure loop into the allocator

Joonsoo Kim
2013-12-05T08:42:14Z

On Wed, Dec 04, 2013 at 04:33:43PM +0000, Christoph Lameter wrote:
> On Thu, 5 Dec 2013, Joonsoo Kim wrote:
>
> > Now we have cpu partial slabs facility, so I think that slowpath isn't really
> > slow. And it doesn't much increase the management overhead in the node
> > partial lists, because of cpu partial slabs.
>
> Well yes that may address some of the issues here.
>
> > And larger frame may cause more slab_lock contention or cmpxchg contention
> > if there are parallel freeings.
> >
> > But, I don't know which one is better. Is larger frame still better? :)
>
> Could you run some tests to figure this one out? There are also
> some situations in which we disable the per cpu partial pages though.
> F.e. for low latency/realtime. I posted in kernel synthetic
> benchmarks for slab a while back. That maybe something to start with.

I could try. But my trial would not figure this out, since my machine has
just 4 cores which normally cannot produce heavy contention.
Anyway, could you tell me where I can find your synthetic benchmarks for slab?

Thanks.