Issue #21953 has been updated by Eregon (Benoit Daloze). @tikkss I think there is an issue with your accounting of memory because it doesn't match the RSS of worker process. This is running your example as-is. ``` $ ruby -v ruby 4.0.2 (2026-03-17 revision d3da9fec82) +PRISM [x86_64-linux] $ ruby spawn.rb 1000 15756 15756 15756 15756 70556 76628 81552 81552 81552 81552 ... ``` But that process I think never used that much memory: ``` $ /usr/bin/time -v ruby worker.rb 1000 ... Maximum resident set size (kbytes): 16248 ``` ``` $ ruby worker_with_rss.rb 1000 16492 16552 16552 16552 ``` with ```ruby # worker_with_rss.rb N_CLASSES = ARGV[0].to_i Thread.new { loop { puts `ps -o rss #{Process.pid}`.lines.last.to_i sleep 0.5 } } N_CLASSES.times do |index| Object.const_set("X" + index.to_s, Class.new do def foo end def bar end def baz end end) end sleep 2 ``` ---------------------------------------- Feature #21953: Allow accessing unshareable objects within a Ractor-local Ruby Box https://bugs.ruby-lang.org/issues/21953#change-117158 * Author: tikkss (Tsutomu Katsube) * Status: Open ---------------------------------------- ### Status Currently, non-main ractors prohibit access to the following objects to prevent data races: * Global variables * Class variables * Unshareable class instance variables * Unshareable constants ### Proposal I would like to propose that allow reading/writing unshareable objects inside a Ruby Box created in a non-main ractor: ```ruby # lib/x.rb class X # can write unshareable objects XXX = "1" @@cvar = "1" @ivar = "1" class << self def cvar; @@cvar; end def ivar; @ivar; end end end # can read unshareable objects $LOAD_PATH # => returns $LOAD_PATH includes lib directory X.cvar # => "1" X.ivar # => "1" X::XXX # => "1" # main.rb Ractor.new do local_box = Ruby::Box.new local_box.eval <<~RUBY base_dir = File.expand_path(File.dirname(__FILE__)) lib_dir = File.join(base_dir, "lib") # can write unshareable objects $LOAD_PATH.unshift(lib_dir) RUBY local_box.require("x") x = local_box::X.new end.join ``` Ruby Box can isolate global/class variables, class/module definitions from other boxes. A Ruby Box created inside a non-main ractor cannot be accessed from other ractor. If that is the case, wouldn’t it be fine to access unshareable objects inside that box? So I would like to propose that allow reading/writing unshareable objects inside a Ruby Box created in a non-main ractor. ### Background We are working on implementing a Ractor based parallel test runner for the test-unit gem. Ractor is a great for parallel processing. However, many existing libraries still rely on class variables or class instance variables for configuration. Ideally, we should reduce the use of class variables or class instance variables. Currently, we tried fixing several non-shareable objects, but we could not resolve all of them yet. We will continue working on this issue, but we are also exploring other approaches. This is the idea begind this proposal. I think the work needed to make objects shareable when running exisiting libraries with Ractor can be reduced. ### FAQ Q: Can we create a Ruby Box inside a non-main ractor? A: Yes: ```ruby Ractor.new {Ruby::Box.new}.join ``` Q: Is a Ruby Box created in a non-main ractor truly inaccessible from other ractor? A: No. I'm not sure if it's intentional, but a Ruby Box is a shareable object. Also, it can be accessed from the main Ractor by using `Ractor#value`: ```ruby Ractor.shareable?(Ruby::Box.new) # => true ``` ```ruby Ractor.new {Ruby::Box.new}.value # => #<Ruby::Box:3,user,optional> ``` To implement this proposal, Ruby Box may need to be an unshareable object, and passing it with `Ractor#value` may need to be disallowed. ---Files-------------------------------- 1000.html (1.01 KB) 10000.html (1.02 KB) 100000.html (1.02 KB) -- https://bugs.ruby-lang.org/