How to get past 1gb memory limit of 64 bit LuaJIT on Linux?

Question

The overview is I am prototyping code to understand my problem space, and I am running into \'PANIC: unprotected error in call to Lua API (not enough memory)\' errors. I am

Answer 1

Only object allocated by LuaJIT itself are limited to the first 2GB of memory. This means that tables, strings, full userdata (i.e. not lightuserdata), and FFI objects allocated with ffi.new will count towards the limit, but objects allocated with malloc, mmap, etc. are not subjected to this limit (regardless if called by a C module or the FFI).

An example for allocating a structure with malloc:

ffi.cdef[[
    typedef struct { int bar; } foo;
    void* malloc(size_t);
    void free(void*);
]]

local foo_t = ffi.typeof("foo")
local foo_p = ffi.typeof("foo*")

function alloc_foo()
    local obj = ffi.C.malloc(ffi.sizeof(foo_t))
    return ffi.cast(foo_p, obj)
end

function free_foo(obj)
    ffi.C.free(obj)
end

The new GC to be implemented in LuaJIT 3.0 IIRC will not have this limit, but I haven't heard any news on it's development recently.

Source: http://lua-users.org/lists/lua-l/2012-04/msg00729.html