[Vm-dev] Immutability through hardware

Igor Stasenko siguctua at gmail.com
Mon May 9 12:16:00 UTC 2011

Just a follow-up to recent thread.

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

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