Migrating an existing more modern GC to D's gc.d

[David Bennett]

On Tuesday, 10 April 2018 at 05:26:28 UTC, Dmitry Olshansky wrote:
> On Monday, 9 April 2018 at 19:50:16 UTC, H. S. Teoh wrote:
>> Last I remembered, you were working on a GC prototype for D?
>
> Still there, but my spare time is super limited lately, the 
> other project preempted that for the moment.
>
>> Any news on that, or have you basically given it up?
>
> Might try to hack to the finish line in one good night, it was 
> pretty close to complete. Debugging would be fun though ;)

I was thinking about messing with the GC in my free time just 
yesterday... how hard would it be:

Add a BlkAttr.THREAD_LOCAL, and set it from the runtime if the 
type or it's members are not shared or __gshared.

Then we could store BlkAttr.THREAD_LOCAL memory in different 
pages (per thread) without having to setting a mutex. (if we need 
to get new page from the global pool we set a mutex for that)

If thats possible we could also Just(TM) scan the current thread 
stack and mark/sweep only those pages. (without a stop the world)

And when a thread ends we could give the pages to the global pool 
without a mark/sweep.

The idea is it works like it does currently unless something is 
invisible to other threads, Or am i missing something obvious? 
(quite likely)