Implement `Process.warmup`

[Feature #18885]

For now, the optimizations performed are:

  - Run a major GC
  - Compact the heap
  - Promote all surviving objects to oldgen

Other optimizations may follow.

1 files changed, 8 insertions, 0 deletions

diff --git a/test/ruby/test_process.rb b/test/ruby/test_process.rb
index 6e8050a54a..fa25d10353 100644
--- a/test/ruby/test_process.rb
+++ b/test/ruby/test_process.rb
@@ -4,6 +4,7 @@ require 'test/unit'
 require 'tempfile'
 require 'timeout'
 require 'rbconfig'
+require 'objspace'
 
 class TestProcess < Test::Unit::TestCase
   RUBY = EnvUtil.rubybin
@@ -2679,4 +2680,11 @@ EOS
       end
     end;
   end if Process.respond_to?(:_fork)
+
+  def test_warmup_promote_all_objects_to_oldgen
+    obj = Object.new
+    refute_includes(ObjectSpace.dump(obj), '"old":true')
+    Process.warmup
+    assert_includes(ObjectSpace.dump(obj), '"old":true')
+  end
 end