Modify heap size or allow heap growth

[emmatyping]

When running

help('modules')

it causes Python to OOM (the heap is limited to 16MB). We should consider using either

1. -s INITIAL_MEMORY=X for something like 20-30MB or
2. just allow memory growth via -s ALLOW_MEMORY_GROWTH=1.

We should maybe also compile with -s ABORTING_MALLOC=0 which makes malloc() return NULL, which will give people a more familiar Python traceback rather than the following:

Uncaught RuntimeError: Aborted(Cannot enlarge memory arrays to size 16855040 bytes (OOM). Either (1) compile with  -s INITIAL_MEMORY=X  with X higher than the current value 16777216, (2) compile with  -s ALLOW_MEMORY_GROWTH=1  which allows increasing the size at runtime, or (3) if you want malloc to return NULL (0) instead of this abort, compile with  -s ABORTING_MALLOC=0 )

[brettcannon]

Are their novel drawbacks for going with the memory growth option compared to the usual potential of things getting out of hand (which I would still assume the browser would take care of)? Otherwise the ABORTING_MALLOC=0 option definitely sounds like a a minimum change to go with.

[tiran]

Does ALLOW_MEMORY_GROWTH=1 have performance implications? I vaguely remember that some document mentioned that growing memory required regular checks or a callback to be efficient.

[emmatyping]

ALLOW_MEMORY_GROWTH was enabled in python/cpython#30552, it seems almost required. There is a performance hit when used, but I think since most things will require a lot more than 16MB memory we should enable it anyway.

[brettcannon]

Should we close this?

[emmatyping]

Yeah, allowing memory growth seems to be the most reasonable solution to this.