ll_alloc reallocate crash

[mliu]

Thanks, Mikael, for the suggestions. The 3GB ceiling did look very
suspicious to me too that it was an address space problem.

Just an update for future reference. After building with 64bit erlang,
we are able to take it far beyond 3GB. But, as some of the other posts
mentioned, erlang/otp's choice to use lists by default in many places
greatly impacts memory use. It turned out we could only support 150K
connections with ~7GB of memory used in the 64bit build. We're also
aware of efficiency gains using binary, and tried to maximize its use,
so it looks to me this 2-fold increase in memory is the minimum we can
expect. So with the current hardware of the machine (8GB), we end up
with the same number of connections for 32/64 bit, with cpu use
remaining consistently low.

We did think about using multiple 32bit nodes on the same machine to
segment connection handling across nodes, but weren't sure whether the
cost in complexity introduced and the extra overhead in inter-node
message passing would balance out with the cost of simply just adding
more memory.

If anyone has any insights in this regard, please reply.

Thanks,
Mike