RE: [RFC v4 0/3] lib/fastmem: fast small-object allocator

> 3. Per-lcore caches: bounded LIFO stacks (no locks on the hot
>    path). Cache misses trigger bulk transfers to/from the shared
>    bin under a spinlock.

I haven't looked at the v4 code in detail, so forgive me if my concern is already addressed.

I am worried that a non-EAL thread can be preempted while holding a fastmem lock.
Could this cause an EAL thread to stall in the fastmem lib under the wrong circumstances?
If so, can this be avoided in any way?

The Lock-Free Stack has a solution using single-linked lists and a 128-bit CAS operation.
The solution is quite slow (due to linked list traversal with retry on collision), but progress is practically guaranteed.