RFR: 8291555: Implement alternative fast-locking scheme [v72]

[Aleksey Shipilev]

On Fri, 5 May 2023 09:56:44 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Full `make images` for `macosx-aarch64-zero-fastdebug` requires #13827. After that, it survives the build with all two `LockingModes`, but not with LockingMode = LM_LIGHTWEIGHT:

This requires significantly more time to implement for Zero. To unblock the rest of the Lilliput work, I suggest we protect Zero with this hunk:


diff --git a/src/hotspot/cpu/zero/vm_version_zero.cpp b/src/hotspot/cpu/zero/vm_version_zero.cpp
index 4c5e343dbbf..3d17e159a61 100644
--- a/src/hotspot/cpu/zero/vm_version_zero.cpp
+++ b/src/hotspot/cpu/zero/vm_version_zero.cpp
@@ -116,6 +116,11 @@ void VM_Version::initialize() {
     FLAG_SET_DEFAULT(UseVectorizedMismatchIntrinsic, false);
   }
 
+  if ((LockingMode != LM_LEGACY) && (LockingMode != LM_MONITOR)) {
+    warning("Unsupported locking mode for this CPU.");
+    FLAG_SET_DEFAULT(LockingMode, LM_LEGACY);
+  }
+
   // Enable error context decoding on known platforms
 #if defined(IA32) || defined(AMD64) || defined(ARM) || \
     defined(AARCH64) || defined(PPC) || defined(RISCV) || \


...and then deal with the rest in https://bugs.openjdk.org/browse/JDK-8307532.

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PR Comment: https://git.openjdk.org/jdk/pull/10907#issuecomment-1536208347