[Vm-dev] Immutability through hardware

[Igor Stasenko]

Just a follow-up to recent thread.

Suppose that we have new object format which supports multiple memory regions.
I.e.
eden space
old space
pinned space
...
and
immutable space

so, instead of adding a flag per object whether its immutable or not,
and then check this flag every time there is a write attempt,
we could simply let hardware handle this.
And immutable space is a memory region with read-only access, So once
placed & sealed , any attempt to write, we lead to a hardware
exception,
which can be nicely handled :)

So, we will have a single entry point for all write access , and don't
need to spread an immutability logic all over the places.
And of course hardware 'check if memory is writeable' is much faster
than software one.

What you think?

-- 
Best regards,
Igor Stasenko AKA sig.