ruby.git/gc/mmtk/mmtk.h, branch v4.0.4

[ruby/mmtk] Implement fast path for bump pointer allocator

2025-12-21T02:55:12+00:00

Adding a fast path for bump pointer allocator can improve allocation
performance.

For the following microbenchmark with MMTK_HEAP_MIN=100MiB:

    10_000_000.times { String.new }

Before:

    810.7 ms ±   8.3 ms    [User: 790.9 ms, System: 40.3 ms]

After:

    777.9 ms ±  10.4 ms    [User: 759.0 ms, System: 37.9 ms]

https://github.com/ruby/mmtk/commit/0ff5c9f579

[ruby/mmtk] Call rb_bug when Ruby mutator thread panics

2025-12-20T13:40:00+00:00

This will allow the Ruby backtrace, memory mapping, etc. to be outputted
when a Ruby mutator thread panics.

https://github.com/ruby/mmtk/commit/d10fd325dd

[ruby/mmtk] Skip weak references that are special consts

2025-07-30T13:26:19+00:00

If a reference marked weak becomes a special const, it will crash because
it is not a GC handled object. We should skip special consts here.

https://github.com/ruby/mmtk/commit/870a79426b

Move `object_id` in object fields.

2025-05-08T05:58:05+00:00

And get rid of the `obj_to_id_tbl`

It's no longer needed, the `object_id` is now stored inline
in the object alongside instance variables.

We still need the inverse table in case `_id2ref` is invoked, but
we lazily build it by walking the heap if that happens.

The `object_id` concern is also no longer a GC implementation
concern, but a generic implementation.

Co-Authored-By: Matt Valentine-House

[ruby/mmtk] Do root scanning in scan_vm_specific_roots

2025-04-08T03:12:50+00:00

We rely on scan_vm_specific_roots to reach all stacks via the following
path:

    VM -> ractors -> threads -> fibers -> stacks

https://github.com/ruby/mmtk/commit/0a6a835aaa

[ruby/mmtk] Trigger forced GC in GC.start

2025-02-24T23:30:00+00:00

We now use `MMTK::handle_user_collection_request(true, ...)` to force
triggering a GC instead of enabling GC temporarily.

https://github.com/ruby/mmtk/commit/02ef47f818

[ruby/mmtk] Add mmtk_heap_max to GC.config

2025-01-17T15:44:24+00:00

https://github.com/ruby/mmtk/commit/6a78ffaf16

[ruby/mmtk] Add mmtk_heap_min to GC.config

2025-01-16T21:40:31+00:00

https://github.com/ruby/mmtk/commit/5bbac70c69

[ruby/mmtk] Add mmtk_heap_mode to GC.config

2025-01-16T16:20:04+00:00

https://github.com/ruby/mmtk/commit/810f897603

[ruby/mmtk] Add mmtk_plan to GC.config

2025-01-15T18:08:03+00:00

https://github.com/ruby/mmtk/commit/67da9ea5b8