`r = Ractor.new{ expr }` generates the block return value from `expr`
and we can get this value by `r.take`. Ractor.yield and Ractor#take
passing values by copying on default. However, the block return value
(we named it "will" in the code) is not referred from the Ractor
because the Ractor is already dead. So we can pass the reference
of "will" to another ractor without copying. We can apply same story
for the propagated exception.
rb_ractor_belonging() returns 0 only if it has sharable flag.
rb_ractor_confirm_belonging() checks rb_ractor_shareable_p()
if the belonging ractor id is different from current ractor id.
rb_objspace_reachable_objects_from(obj) is used to traverse all
reachable objects from obj. This function modify objspace but it
is not ractor-safe (thread-safe). This patch fix the problem.
Strategy:
(1) call GC mark process during_gc
(2) call Ractor-local custom mark func when !during_gc
To access TLS, it is faster to use language TLS specifier instead
of using pthread_get/setspecific functions.
Original proposal is: Use native thread locals. #3665
Ractor#close_outgoing should cancel waiting Ractor.yield. However,
yield a value by the Ractor's block should not cancel (to recognize
terminating Ractor, introduce rb_ractor_t::yield_atexit flag).
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.
