iv_index_tbl manages instance variable indexes (ID -> index).
This data structure should be synchronized with other ractors
so introduce some VM locks.
This patch also introduced atomic ivar cache used by
set/getinlinecache instructions. To make updating ivar cache (IVC),
we changed iv_index_tbl data structure to manage (ID -> entry)
and an entry points serial and index. IVC points to this entry so
that cache update becomes atomically.
(1) recorded_lock_rec > current_lock_rec should not be occurred
on rb_ec_vm_lock_rec_release().
(2) should be release VM lock at EXEC_TAG(), not POP_TAG().
(3) some refactoring.
If a ractor getting a VM lock (monitor) raises an exception,
unlock can be skipped. To release VM lock correctly on exception
(or other jumps with JUMP_TAG), EC_POP_TAG() releases VM lock.
This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.
[Feature #17100]
This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.
I hope this feature can help programmers from thread-safety issues.
