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Re: an idea to speed up GC
On Sat, Mar 11, 2000 at 04:01:38PM -0800, Mark Mitchell wrote:
> >>>>> "Zack" == Zack Weinberg <zack@wolery.cumb.org> writes:
>
> Zack> Suppose we add a second set of mark bits, call it the frozen
> Zack> set. You can ask the garbage collector to mark some
> Zack> structure, or all of the roots, and then copy the mark bits
> Zack> to the frozen bits. Then, instead of clearing all the mark
> Zack> bits at the start of a GC run, we copy the frozen bits to
> Zack> the mark bits.
>
> Zack> Does this sound worthwhile?
>
> We thought about something similar. But, the problem is that some of
> these things might end up pointing to different things: just because
> `a' will always be marked doesn't mean that the things reachable from
> `a' will have already been marked.
This surprises me greatly. When are we going to modify a type, for
instance, after it's been created and hashed? Or the saved RTL or
tree for an inline function?
zw