8338929: Make Metaspace::deallocate space-aware

Reviewed-by: coleenp, adinn

Author: tstuefe

src/hotspot/share/memory/classLoaderMetaspace.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2020 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -130,9 +130,10 @@ MetaWord* ClassLoaderMetaspace::expand_and_allocate(size_t word_size, Metaspace:
 
 // Prematurely returns a metaspace allocation to the _block_freelists
 // because it is not needed anymore.
-void ClassLoaderMetaspace::deallocate(MetaWord* ptr, size_t word_size, bool is_class) {
+void ClassLoaderMetaspace::deallocate(MetaWord* ptr, size_t word_size) {
   MutexLocker fcl(lock(), Mutex::_no_safepoint_check_flag);
-  if (Metaspace::using_class_space() && is_class) {
+  const bool is_class = Metaspace::using_class_space() && Metaspace::is_in_class_space(ptr);
+  if (is_class) {
     class_space_arena()->deallocate(ptr, word_size);
   } else {
     non_class_space_arena()->deallocate(ptr, word_size);

src/hotspot/share/memory/classLoaderMetaspace.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2024, 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
@@ -92,7 +92,7 @@ class ClassLoaderMetaspace : public CHeapObj<mtClass> {
 
   // Prematurely returns a metaspace allocation to the _block_freelists
   // because it is not needed anymore.
-  void deallocate(MetaWord* ptr, size_t word_size, bool is_class);
+  void deallocate(MetaWord* ptr, size_t word_size);
 
   // Update statistics. This walks all in-use chunks.
   void add_to_statistics(metaspace::ClmsStats* out) const;

src/hotspot/share/memory/metadataFactory.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2024, 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
@@ -54,7 +54,7 @@ class MetadataFactory : AllStatic {
       assert(loader_data != nullptr, "shouldn't pass null");
       assert(!data->is_shared(), "cannot deallocate array in shared spaces");
       int size = data->size();
-      loader_data->metaspace_non_null()->deallocate((MetaWord*)data, size, false);
+      loader_data->metaspace_non_null()->deallocate((MetaWord*)data, size);
     }
   }
 
@@ -68,15 +68,14 @@ class MetadataFactory : AllStatic {
       assert(!md->on_stack(), "can't deallocate things on stack");
       assert(!md->is_shared(), "cannot deallocate if in shared spaces");
       md->deallocate_contents(loader_data);
-      bool is_klass = md->is_klass();
       // Call the destructor. This is currently used for MethodData which has a member
       // that needs to be destructed to release resources. Most Metadata derived classes have noop
       // destructors and/or cleanup using deallocate_contents.
       // T is a potentially const or volatile qualified pointer. Remove any const
       // or volatile so we can call the destructor of the type T points to.
       using U = std::remove_cv_t<T>;
       md->~U();
-      loader_data->metaspace_non_null()->deallocate((MetaWord*)md, size, is_klass);
+      loader_data->metaspace_non_null()->deallocate((MetaWord*)md, size);
     }
   }
 };

src/hotspot/share/memory/metaspace.cpp

@@ -538,6 +538,8 @@ void MetaspaceGC::compute_new_size() {
 //////  Metaspace methods /////
 
 const MetaspaceTracer* Metaspace::_tracer = nullptr;
+const void* Metaspace::_class_space_start = nullptr;
+const void* Metaspace::_class_space_end = nullptr;
 
 bool Metaspace::initialized() {
   return metaspace::MetaspaceContext::context_nonclass() != nullptr
@@ -570,6 +572,8 @@ void Metaspace::initialize_class_space(ReservedSpace rs) {
          "wrong alignment");
 
   MetaspaceContext::initialize_class_space_context(rs);
+  _class_space_start = rs.base();
+  _class_space_end = rs.end();
 }
 
 // Returns true if class space has been setup (initialize_class_space).
@@ -979,17 +983,15 @@ void Metaspace::purge(bool classes_unloaded) {
   MetaspaceCriticalAllocation::process();
 }
 
-bool Metaspace::contains(const void* ptr) {
-  if (MetaspaceShared::is_in_shared_metaspace(ptr)) {
-    return true;
-  }
-  return contains_non_shared(ptr);
-}
 
-bool Metaspace::contains_non_shared(const void* ptr) {
-  if (using_class_space() && VirtualSpaceList::vslist_class()->contains((MetaWord*)ptr)) {
-     return true;
-  }
+// Returns true if pointer points into one of the metaspace regions, or
+// into the class space.
+bool Metaspace::is_in_shared_metaspace(const void* ptr) {
+  return MetaspaceShared::is_in_shared_metaspace(ptr);
+}
 
+// Returns true if pointer points into one of the non-class-space metaspace regions.
+bool Metaspace::is_in_nonclass_metaspace(const void* ptr) {
   return VirtualSpaceList::vslist_nonclass()->contains((MetaWord*)ptr);
 }
+

src/hotspot/share/memory/metaspace.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2011, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2017, 2021 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -64,6 +64,10 @@ class Metaspace : public AllStatic {
 
   static const MetaspaceTracer* _tracer;
 
+  // For quick pointer testing: extent of class space; nullptr if no class space.
+  static const void* _class_space_start;
+  static const void* _class_space_end;
+
   static bool _initialized;
 
 public:
@@ -113,8 +117,32 @@ class Metaspace : public AllStatic {
   static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size,
                             MetaspaceObj::Type type);
 
-  static bool contains(const void* ptr);
-  static bool contains_non_shared(const void* ptr);
+  // Returns true if the pointer points into class space, non-class metaspace, or the
+  // metadata portion of the CDS archive.
+  static bool contains(const void* ptr) {
+    return is_in_shared_metaspace(ptr) || // in cds
+           is_in_class_space(ptr) ||      // in class space
+           is_in_nonclass_metaspace(ptr); // in one of the non-class regions?
+  }
+
+  // Returns true if the pointer points into class space or into non-class metaspace
+  static bool contains_non_shared(const void* ptr) {
+    return is_in_class_space(ptr) ||      // in class space
+           is_in_nonclass_metaspace(ptr); // in one of the non-class regions?
+  }
+
+  // Returns true if pointer points into the CDS klass region.
+  static bool is_in_shared_metaspace(const void* ptr);
+
+  // Returns true if pointer points into one of the non-class-space metaspace regions.
+  static bool is_in_nonclass_metaspace(const void* ptr);
+
+  // Returns true if pointer points into class space, false if it doesn't or if
+  // there is no class space. Class space is a contiguous region, which is why
+  // two address comparisons are enough.
+  static inline bool is_in_class_space(const void* ptr) {
+    return ptr < _class_space_end && ptr >= _class_space_start;
+  }
 
   // Free empty virtualspaces
   static void purge(bool classes_unloaded);

test/hotspot/gtest/metaspace/test_metaspace_misc.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2024, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2020 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -67,7 +67,7 @@ TEST_VM(metaspace, misc_max_alloc_size)   {
       ASSERT_NOT_NULL(p);
     }
     // And also, successfully deallocate it.
-    cld->metaspace_non_null()->deallocate(p, sz, in_class_space);
+    cld->metaspace_non_null()->deallocate(p, sz);
   }
 }