[Lse-tech] [RFC] Dynamic percpu data allocator

[Dipankar S. <dip...@in...>]

If static percpu area is around, can dynamic percpu data allocator
be far behind ;-)

As a part of scalable kernel primitives work for higher-end SMP
and NUMA architectures, we have been seeing increasing need
for per-cpu data in various key areas. Rusty's percpu area
work has added a way in 2.5 kernels to maintain static per-cpu
data. Inspired by that work, I have implemented a dynamic per-cpu
data allocator. Currently it is useful to us for -

1. Per-cpu data in dynamically allocated structures.
2. per-cpu statistics and reference counters
3. Per-cpu data in drivers/modules.
4. Scalable locking primitives like local spin only locks
   (or even big reader locks).

Included in this mail is a document that describes the allocator.
I would really appreciate if people comment on it. I am
particularly interested in eek-value of the interfaces,
specially the bit about keeping the type information in
a dummy variable in a union.

The actual patch will follow soon, unless someone convince
me quickly that there is an saner way to do this.

Thanks
-- 
Dipankar Sarma  <dip...@in...> http://lse.sourceforge.net
Linux Technology Center, IBM Software Lab, Bangalore, India.