* Fix race condition in signal handler query
* Initialize signal lock dynamically and reset after fork
* Fix signal handler mutex initialization conditions
Previously rb_ractor_interrupt_exec would use an intermediate function
to create a new thread with the actual target function, replacing the
data being passed in with a piece of malloc memory holding the "next"
function and the original data.
Because of this, passing rb_interrupt_exec_flag_value_data to
rb_ractor_interrupt_exec didn't have the intended effect of allowing
data to be passed in and marked.
This commit adds a rb_interrupt_exec_flag_new_thread flag, which
both simplifies the implementation and allows the original data to be
marked.
We never freed any resources of rb_native_thread at fork because it would
cause it to hang. This is because it called rb_native_cond_destroy for
condition variables. We can't call rb_native_cond_destroy here because
according to the specs of pthread_cond_destroy:
Attempting to destroy a condition variable upon which other threads
are currently blocked results in undefined behavior.
Specifically, glibc's pthread_cond_destroy waits on all the other listeners.
Since after forking all the threads are dead, the condition variable's
listeners will never wake up, so it will hang forever.
This commit changes it to only free the memory and none of the condition
variables.
* Added `Ractor::Port`
* `Ractor::Port#receive` (support multi-threads)
* `Rcator::Port#close`
* `Ractor::Port#closed?`
* Added some methods
* `Ractor#join`
* `Ractor#value`
* `Ractor#monitor`
* `Ractor#unmonitor`
* Removed some methods
* `Ractor#take`
* `Ractor.yield`
* Change the spec
* `Racotr.select`
You can wait for multiple sequences of messages with `Ractor::Port`.
```ruby
ports = 3.times.map{ Ractor::Port.new }
ports.map.with_index do |port, ri|
Ractor.new port,ri do |port, ri|
3.times{|i| port << "r#{ri}-#{i}"}
end
end
p ports.each{|port| pp 3.times.map{port.receive}}
```
In this example, we use 3 ports, and 3 Ractors send messages to them respectively.
We can receive a series of messages from each port.
You can use `Ractor#value` to get the last value of a Ractor's block:
```ruby
result = Ractor.new do
heavy_task()
end.value
```
You can wait for the termination of a Ractor with `Ractor#join` like this:
```ruby
Ractor.new do
some_task()
end.join
```
`#value` and `#join` are similar to `Thread#value` and `Thread#join`.
To implement `#join`, `Ractor#monitor` (and `Ractor#unmonitor`) is introduced.
This commit changes `Ractor.select()` method.
It now only accepts ports or Ractors, and returns when a port receives a message or a Ractor terminates.
We removes `Ractor.yield` and `Ractor#take` because:
* `Ractor::Port` supports most of similar use cases in a simpler manner.
* Removing them significantly simplifies the code.
We also change the internal thread scheduler code (thread_pthread.c):
* During barrier synchronization, we keep the `ractor_sched` lock to avoid deadlocks.
This lock is released by `rb_ractor_sched_barrier_end()`
which is called at the end of operations that require the barrier.
* fix potential deadlock issues by checking interrupts just before setting UBF.
https://bugs.ruby-lang.org/issues/21262
Although it almost certainly works in this case, volatile is best not
used for multi-threaded code. Using atomics instead avoids warnings from
TSan.
This also simplifies some logic, as system_working was previously only
ever assigned to 1, so --system_working <= 0 should always return true
(unless it underflowed).
Rework ractors so that any ractor action (Ractor.receive, Ractor#send, Ractor.yield, Ractor#take,
Ractor.select) will operate on the thread that called the action. It will put that thread to sleep if
it's a blocking function and it needs to put it to sleep, and the awakening action (Ractor.yield,
Ractor#send) will wake up the blocked thread.
Before this change every blocking ractor action was associated with the ractor struct and its fields.
If a ractor called Ractor.receive, its wait status was wait_receiving, and when another ractor calls
r.send on it, it will look for that status in the ractor struct fields and wake it up. The problem was that
what if 2 threads call blocking ractor actions in the same ractor. Imagine if 1 thread has called Ractor.receive
and another r.take. Then, when a different ractor calls r.send on it, it doesn't know which ruby thread is associated
to which ractor action, so what ruby thread should it schedule? This change moves some fields onto the ruby thread
itself so that ruby threads are the ones that have ractor blocking statuses, and threads are then specifically scheduled
when unblocked.
Fixes [#17624]
Fixes [#21037]
Ractors created in a parent process should be properly shut down in the
child process. They need their cache cleared and status set to
"terminated"
Co-authored-by: John Hawthorn <john@hawthorn.email>
[Bug #17506]
`Thread.current.group` isn't shareable so it shouldn't be inherited
by the main thread of a new Ractor.
This cause an extra allocation when spawning a ractor, which could
be elided with a bit of extra work, but not sure if it's worth
the effort.
If a thread was holding this lock before fork, it will not exist in the
child process. We should re-initialize these locks as we do with the VM
locks when forking.
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
Previously, Ruby displayed backtraces for each thread on deadlock. However, it has not been shown since Ruby 3.0.
It should display the backtrace for debugging.
Co-authored-by: Jeremy Evans <code@jeremyevans.net>
This commit adds an environment variable `RUBY_THREAD_TIMESLICE` for
specifying the default thread quantum in milliseconds. You can adjust
this variable to tune throughput, which is especially useful on
multithreaded systems that are mixing CPU bound work and IO bound work.
The default quantum remains 100ms.
[Feature #20861]
Co-Authored-By: John Hawthorn <john@hawthorn.email>
If one thread is reading and another closes that socket, the close
blocks waiting for the read to abort cleanly. This ensures that Ruby is
totally done with the file descriptor _BEFORE_ we tell the OS to close
and potentially re-use it.
When the read is correctly terminated, the close should be unblocked.
That currently works if closing is happening on a thread, but if it's
happening on a fiber with a fiber scheduler, it does NOT work.
This patch ensures that if the close happened in a fiber scheduled
thread, that the scheduler is notified that the fiber is unblocked.
[Bug #20723]
Fixes this compiler warning:
thread.c:4530:18: warning: storing the address of local variable ‘stack_end’ in ‘*stack_end_p’ [-Wdangling-pointer=]
4530 | *stack_end_p = &stack_end;
| ~~~~~~~~~~~~~^~~~~~~~~~~~
* This PR from the timeout gem (https://github.com/ruby/timeout/pull/30) made it so you have to handle_interrupt on Timeout::ExitException instead of Timeout::Error
* Efficiency changes to the gem (one shared thread) mean you can't consistently handle timeout errors using handle_timeout: https://github.com/ruby/timeout/issues/41
Previously, a TypeError was not raised if there were no thread
variables, because the conversion to symbol was done after that
check. Convert to symbol before checking for whether thread
variables are set to make the behavior consistent.
Fixes [Bug #20606]
