DirectBufferAllocTest fails after replacement of Thread.sleep() with Thread.onSpinWait()

[Сергей Цыпанов]

Hello,

while playing with Thread.onSpinWait() in busy-wait loops I've replaced 
Thread.sleep() with
preferable (at least as it appears from the JavaDoc) Thread.onSpinWait() in 
java.nio.Bits.

Immediately after that DirectBufferAllocTest started to fail with OOME. This is 
surprising, as the change
does not seem to change any program logic:

diff --git a/src/java.base/share/classes/java/nio/Bits.java 
b/src/java.base/share/classes/java/nio/Bits.java
--- a/src/java.base/share/classes/java/nio/Bits.java    (revision 
7d4df6a83f6333e0e73686b807ee5d4b0ac10cd2)
+++ b/src/java.base/share/classes/java/nio/Bits.java    (date 1655709575452)
@@ -162,8 +162,7 @@
                 }
                 try {
                     if (!jlra.waitForReferenceProcessing()) {
-                        Thread.sleep(sleepTime);
-                        sleepTime <<= 1;
+                        Thread.onSpinWait();
                         sleeps++;
                     }
                 } catch (InterruptedException e) {

Another surprise here is that when I copy the test as simple Java application
it fails when I run it with the same JVM options (-XX:MaxDirectMemorySize=128m 
-XX:-ExplicitGCInvokesConcurrent),
but doesn't if I put a breakpoint in IntelliJ at sleeps++ and stop there for 
6-7 times while
the test is running. No failure observed if I drop JVM options either.

Is it a bug somewhere in GC/runtime or am I doing something wrong?

Regards,
Sergey Tsypanov