diff --git a/src/hotspot/share/gc/shared/space.cpp b/src/hotspot/share/gc/shared/space.cpp
index 011a0f5cfd8..84ba21527fd 100644
--- a/src/hotspot/share/gc/shared/space.cpp
+++ b/src/hotspot/share/gc/shared/space.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -30,7 +30,6 @@
 #include "memory/iterator.inline.hpp"
 #include "memory/universe.hpp"
 #include "oops/oop.inline.hpp"
-#include "runtime/atomicAccess.hpp"
 #include "runtime/java.hpp"
 #include "runtime/safepoint.hpp"
 #include "utilities/align.hpp"
@@ -69,7 +68,7 @@ void ContiguousSpace::clear(bool mangle_space) {
 #ifndef PRODUCT
 
 void ContiguousSpace::mangle_unused_area() {
-  mangle_unused_area(MemRegion(_top, _end));
+  mangle_unused_area(MemRegion(top(), _end));
 }
 
 void ContiguousSpace::mangle_unused_area(MemRegion mr) {
@@ -128,11 +127,8 @@ inline HeapWord* ContiguousSpace::par_allocate_impl(size_t size) {
     HeapWord* obj = top();
     if (pointer_delta(end(), obj) >= size) {
       HeapWord* new_top = obj + size;
-      HeapWord* result = AtomicAccess::cmpxchg(top_addr(), obj, new_top);
-      // result can be one of two:
-      //  the old top value: the exchange succeeded
-      //  otherwise: the new value of the top is returned.
-      if (result == obj) {
+      // Retry if we did not successfully updated the top pointers.
+      if (_top.compare_set(obj, new_top)) {
         assert(is_object_aligned(obj) && is_object_aligned(new_top), "checking alignment");
         return obj;
       }
diff --git a/src/hotspot/share/gc/shared/space.hpp b/src/hotspot/share/gc/shared/space.hpp
index 7f2887275b3..05b22f680bf 100644
--- a/src/hotspot/share/gc/shared/space.hpp
+++ b/src/hotspot/share/gc/shared/space.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,6 +32,7 @@
 #include "memory/iterator.hpp"
 #include "memory/memRegion.hpp"
 #include "oops/markWord.hpp"
+#include "runtime/atomic.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "utilities/align.hpp"
 #include "utilities/macros.hpp"
@@ -53,7 +54,7 @@ class ContiguousSpace: public CHeapObj<mtGC> {
 private:
   HeapWord* _bottom;
   HeapWord* _end;
-  HeapWord* _top;
+  Atomic<HeapWord*> _top;
 
   // Allocation helpers (return null if full).
   inline HeapWord* allocate_impl(size_t word_size);
@@ -64,12 +65,12 @@ public:
 
   // Accessors
   HeapWord* bottom() const         { return _bottom; }
-  HeapWord* end() const            { return _end;    }
-  HeapWord* top() const            { return _top;    }
+  HeapWord* end() const            { return _end; }
+  HeapWord* top() const            { return _top.load_relaxed();    }
 
   void set_bottom(HeapWord* value) { _bottom = value; }
   void set_end(HeapWord* value)    { _end = value; }
-  void set_top(HeapWord* value)    { _top = value; }
+  void set_top(HeapWord* value)    { _top.store_relaxed(value); }
 
   // Testers
   bool is_empty() const              { return used() == 0; }
@@ -121,9 +122,6 @@ public:
   // Iteration
   void object_iterate(ObjectClosure* blk);
 
-  // Addresses for inlined allocation
-  HeapWord** top_addr() { return &_top; }
-
   // Debugging
   void verify() const;
 };
diff --git a/src/hotspot/share/gc/shared/vmStructs_gc.hpp b/src/hotspot/share/gc/shared/vmStructs_gc.hpp
index db968e28f67..6a29eb25b37 100644
--- a/src/hotspot/share/gc/shared/vmStructs_gc.hpp
+++ b/src/hotspot/share/gc/shared/vmStructs_gc.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -97,7 +97,7 @@
                                                                                                                                      \
   nonstatic_field(ContiguousSpace,             _bottom,                                       HeapWord*)                             \
   nonstatic_field(ContiguousSpace,             _end,                                          HeapWord*)                             \
-  nonstatic_field(ContiguousSpace,             _top,                                          HeapWord*)                             \
+  nonstatic_field(ContiguousSpace,             _top,                                          Atomic<HeapWord*>)                     \
                                                                                                                                      \
   nonstatic_field(MemRegion,                   _start,                                        HeapWord*)                             \
   nonstatic_field(MemRegion,                   _word_size,                                    size_t)
diff --git a/src/hotspot/share/runtime/vmStructs.cpp b/src/hotspot/share/runtime/vmStructs.cpp
index 4ecc8f9ca01..02572e16728 100644
--- a/src/hotspot/share/runtime/vmStructs.cpp
+++ b/src/hotspot/share/runtime/vmStructs.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -901,6 +901,7 @@
   /*****************************/                                         \
                                                                           \
   declare_toplevel_type(void*)                                            \
+  declare_toplevel_type(Atomic<HeapWord*>)                                \
   declare_toplevel_type(int*)                                             \
   declare_toplevel_type(char*)                                            \
   declare_toplevel_type(char**)                                           \