LuaTask and memory allocation

[Paul Ducklin <duck@...>]

Using LuaTask 1.6.0 statically linked into
Lua 5.1.2. (A few other packages are built-in,
namely the LuaSocket core, lfs, lrandom, bitlib
and struct.) This is on Linux.

Starting Lua, mem use (as shown by top) is about
1m resident, 2.2m allocated (virtual). Seems quite 
modest to me.

Every time I call task.create() (even if the tasks
do nothing but sleep immediately) mem usage goes
up by about 70k resident, but a whopping 8m 
of virtual memory. So with 250 tasks I am _using_ 
just 17m but have 2g allocated! Perhaps unsurprisingly,
at 257 tasks Lua segfaults...

Why 2m for Lua but an additional 8m of virtual memory
for each created task, esp. when the task is only
_using_ a modest 70k?

I was rather hoping to handle a couple of hundred 
proxied sockets inside a simple Lua program... whilst
there is plenty of physical memory to support this I
am, absurdly, running out of address space :-)

What's going on?