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, 7 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index afcfb374fc..1b9f87c09b 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -35,6 +35,13 @@ Note: We're only listing outstanding class updates.
       The class use equality semantic to lookup keys like a regular hash,
       but it doesn't hold strong references on the keys. [[Feature #18498]]
 
+* Process.warnup
+
+    * Notify the Ruby virtual machine that the boot sequence is finished,
+      and that now is a good time to optimize the application. This is useful
+      for long running applications. The actual optimizations performed are entirely
+      implementation specific and may change in the future without notice. [[Feature #18885]
+
 ## Stdlib updates
 
 The following default gems are updated.