Ruby Issue Tracking System

05/20/2026

09:14 PM Ruby Revision ec114e57 (git): Use monotonic add/sub counters for malloc_increase

Replace the single
objspace->malloc_counters.{increase,oldmalloc_increase} size_t fields
with pairs of monotonically-increasing counters. Snapshots of these
counters are taken at each GC, so that the live malloc_increase is computed as
... eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 672ef432 (git): Expose monotonic malloc/free totals via GC.stat

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 8f7e07bb (git): Reorder rb_gc_impl_stat to keep heap_live_slots accurate

Several SETs in rb_gc_impl_stat may allocate a T_BIGNUM RVALUE when
the value exceeds FIXNUM_MAX
This is invisible on LP64 but trips on LLP64 Windows and ILP32 Linux
where FIXNUM_MAX ~= 1.07GB.
If those allocations happen *after* setti... eightbitraptor (Matt V-H)

09:14 PM Ruby Revision cb3b126e (git): Better feature detection for malloc counter locks

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision ed882010 (git): Make sure we flush the cached count to update heap slots

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 8b7c4342 (git): Snapshot malloc counters at end of sweep

Snapshotting at start of marking lets sweep-time frees count against the
next epoch, which roughly halves GC frequency on alloc-heavy workloads.
Move the snapshot to end of sweep so the next epoch starts from a clean
baseline. eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 4c8f0727 (git): Unify gc_counter_t on rbimpl_atomic_uint64_t

eightbitraptor (Matt V-H)

09:14 PM Ruby Revision 3002cea4 (git): Fix GC Bug in imemo cdhash creation

It's possible for st_init_existing_table_with_size to trigger GC. If
that happens we need to ensure that the table entries count doesn't
contain garbage data, or we'll try and mark random stuff eightbitraptor (Matt V-H)

10:44 AM Ruby Revision 332315a4 (git): Preserve usable slot size when RVALUE_OVERHEAD is non-zero

We made a mistake calculating slot sizes during the heap slot sizes
refactor. Previously BASE_SLOT_SIZE included RVALUE_OVERHEAD, this was
lost during the refactor to use the SLOT macro.
The result of this was that when Ruby was compile... eightbitraptor (Matt V-H)

05/14/2026

09:26 AM Ruby Revision 69857ea9 (git): Enable debug env in tests, so RUBY_DEBUG env var is respected

The GC RUBY_DEBUG=gc_stress bug should have been caught by
test_gc_stress_at_startup, but because RUBY_DEBUG has been ignored on
CI, the subprocess wasn't actually running stress at startup eightbitraptor (Matt V-H)