Hi,

here the latest effort, it includes a whole new trivial allocator with a
horrid name and an almost full rewrite of the deadlock prevention core.
This version does not do anything per device and hence does not depend 
on the new netdev_alloc_skb() API.

The reason to add a second allocator to the receive side is twofold:
1) it allows easy detection of the memory pressure / OOM situation;
2) it allows the receive path to be unbounded and go at full speed when
   resources permit.

The choice of using the global memalloc reserve as a mempool makes that
the new allocator has to release pages as soon as possible; if we were
to hoard pages in the allocator the memalloc reserve would not get 
replenished readily.

Peter