8351216: ZGC: Store NUMA node count

src/hotspot/os/bsd/gc/z/zNUMA_bsd.cpp

@@ -26,10 +26,7 @@
 
 void ZNUMA::pd_initialize() {
   _enabled = false;
-}
-
-uint32_t ZNUMA::count() {
-  return 1;
+  _count = 1;
 }
 
 uint32_t ZNUMA::id() {

src/hotspot/os/linux/gc/z/zNUMA_linux.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, 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
@@ -32,15 +32,9 @@
 
 void ZNUMA::pd_initialize() {
   _enabled = UseNUMA;
-}
-
-uint32_t ZNUMA::count() {
-  if (!_enabled) {
-    // NUMA support not enabled
-    return 1;
-  }
-
-  return os::Linux::numa_max_node() + 1;
+  _count = UseNUMA
+      ? os::Linux::numa_max_node() + 1
+      : 1;
 }
 
 uint32_t ZNUMA::id() {
@@ -65,7 +59,7 @@ uint32_t ZNUMA::memory_id(uintptr_t addr) {
     fatal("Failed to get NUMA id for memory at " PTR_FORMAT " (%s)", addr, err.to_string());
   }
 
-  assert(id < count(), "Invalid NUMA id");
+  assert(id < _count, "Invalid NUMA id");
 
   return id;
 }

src/hotspot/os/windows/gc/z/zNUMA_windows.cpp

@@ -25,10 +25,7 @@
 
 void ZNUMA::pd_initialize() {
   _enabled = false;
-}
-
-uint32_t ZNUMA::count() {
-  return 1;
+  _count = 1;
 }
 
 uint32_t ZNUMA::id() {

src/hotspot/share/gc/z/zNUMA.cpp

@@ -25,13 +25,14 @@
 #include "gc/z/zNUMA.hpp"
 
 bool ZNUMA::_enabled;
+uint32_t ZNUMA::_count;
 
 void ZNUMA::initialize() {
   pd_initialize();
 
   log_info_p(gc, init)("NUMA Support: %s", to_string());
   if (_enabled) {
-    log_info_p(gc, init)("NUMA Nodes: %u", count());
+    log_info_p(gc, init)("NUMA Nodes: %u", _count);
   }
 }
 

src/hotspot/share/gc/z/zNUMA.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2016, 2025, 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
@@ -29,7 +29,8 @@
 
 class ZNUMA : public AllStatic {
 private:
-  static bool _enabled;
+  static bool     _enabled;
+  static uint32_t _count;
 
   static void pd_initialize();
 

src/hotspot/share/gc/z/zNUMA.inline.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2025, 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
@@ -30,4 +30,8 @@ inline bool ZNUMA::is_enabled() {
   return _enabled;
 }
 
+inline uint32_t ZNUMA::count() {
+  return _count;
+}
+
 #endif // SHARE_GC_Z_ZNUMA_INLINE_HPP

src/hotspot/share/gc/z/zPageCache.cpp

@@ -23,7 +23,7 @@
 
 #include "gc/z/zGlobals.hpp"
 #include "gc/z/zList.inline.hpp"
-#include "gc/z/zNUMA.hpp"
+#include "gc/z/zNUMA.inline.hpp"
 #include "gc/z/zPage.inline.hpp"
 #include "gc/z/zPageCache.hpp"
 #include "gc/z/zStat.hpp"