From baf0f45fc7701d2a7d1058e136558ac5642030cd Mon Sep 17 00:00:00 2001
From: Thomas Schatzl <tschatzl@openjdk.org>
Date: Fri, 12 Jun 2026 08:53:57 +0000
Subject: [PATCH] 8385901: G1:
 G1FullGCPrepareTask::_has_free_compaction_targets should be Atomic

Reviewed-by: ayang, iwalulya
---
 src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp | 6 +++---
 src/hotspot/share/gc/g1/g1FullGCPrepareTask.hpp | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp b/src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp
index 86297086b44..031f8ecf601 100644
--- a/src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp
+++ b/src/hotspot/share/gc/g1/g1FullGCPrepareTask.cpp
@@ -60,13 +60,13 @@ G1FullGCPrepareTask::G1FullGCPrepareTask(G1FullCollector* collector) :
 }
 
 void G1FullGCPrepareTask::set_has_free_compaction_targets() {
-  if (!_has_free_compaction_targets) {
-    _has_free_compaction_targets = true;
+  if (!has_free_compaction_targets()) {
+    _has_free_compaction_targets.store_relaxed(true);
   }
 }
 
 bool G1FullGCPrepareTask::has_free_compaction_targets() {
-  return _has_free_compaction_targets;
+  return _has_free_compaction_targets.load_relaxed();
 }
 
 void G1FullGCPrepareTask::work(uint worker_id) {
diff --git a/src/hotspot/share/gc/g1/g1FullGCPrepareTask.hpp b/src/hotspot/share/gc/g1/g1FullGCPrepareTask.hpp
index 9d2887c01a6..57bb036d6a0 100644
--- a/src/hotspot/share/gc/g1/g1FullGCPrepareTask.hpp
+++ b/src/hotspot/share/gc/g1/g1FullGCPrepareTask.hpp
@@ -28,6 +28,7 @@
 #include "gc/g1/g1FullGCTask.hpp"
 #include "gc/g1/g1HeapRegion.hpp"
 #include "memory/allocation.hpp"
+#include "runtime/atomic.hpp"
 
 class G1CollectedHeap;
 class G1CMBitMap;
@@ -61,7 +62,7 @@ public:
 };
 
 class G1FullGCPrepareTask : public G1FullGCTask {
-  volatile bool     _has_free_compaction_targets;
+  Atomic<bool> _has_free_compaction_targets;
   G1HeapRegionClaimer _hrclaimer;
 
   void set_has_free_compaction_targets();