8248391: Unify handling of all OopStorage instances in weak root proc…

…essing

OopStorage instance now owned by subsystems, and generalize dead entry notification

Co-authored-by: Erik Osterlund <erik.osterlund@oracle.com>
Co-authored-by: Stefan Karlsson <stefan.karlsson@oracle.com>
Reviewed-by: coleenp, tschatzl

src/hotspot/share/classfile/classLoaderData.cpp

@@ -488,7 +488,7 @@ void ClassLoaderData::add_class(Klass* k, bool publicize /* true */) {
 void ClassLoaderData::initialize_holder(Handle loader_or_mirror) {
   if (loader_or_mirror() != NULL) {
     assert(_holder.is_null(), "never replace holders");
-    _holder = WeakHandle(OopStorageSet::vm_weak(), loader_or_mirror);
+    _holder = WeakHandle(Universe::vm_weak(), loader_or_mirror);
   }
 }
 
@@ -655,7 +655,7 @@ ClassLoaderData::~ClassLoaderData() {
   ClassLoaderDataGraph::dec_instance_classes(cl.instance_class_released());
 
   // Release the WeakHandle
-  _holder.release(OopStorageSet::vm_weak());
+  _holder.release(Universe::vm_weak());
 
   // Release C heap allocated hashtable for all the packages.
   if (_packages != NULL) {

src/hotspot/share/classfile/dictionary.cpp

@@ -407,14 +407,14 @@ oop SymbolPropertyEntry::method_type() const {
 }
 
 void SymbolPropertyEntry::set_method_type(oop p) {
-  _method_type = OopHandle(OopStorageSet::vm_global(), p);
+  _method_type = OopHandle(Universe::vm_global(), p);
 }
 
 void SymbolPropertyEntry::free_entry() {
   // decrement Symbol refcount here because hashtable doesn't.
   literal()->decrement_refcount();
   // Free OopHandle
-  _method_type.release(OopStorageSet::vm_global());
+  _method_type.release(Universe::vm_global());
 }
 
 SymbolPropertyTable::SymbolPropertyTable(int table_size)

src/hotspot/share/classfile/protectionDomainCache.cpp

@@ -94,7 +94,7 @@ void ProtectionDomainCacheTable::unlink() {
           LogStream ls(lt);
           ls.print_cr("protection domain unlinked at %d", i);
         }
-        entry->literal().release(OopStorageSet::vm_weak());
+        entry->literal().release(Universe::vm_weak());
         *p = entry->next();
         free_entry(entry);
       }
@@ -181,7 +181,7 @@ ProtectionDomainCacheEntry* ProtectionDomainCacheTable::add_entry(int index, uns
     protection_domain->print_value_on(&ls);
     ls.cr();
   }
-  WeakHandle w(OopStorageSet::vm_weak(), protection_domain);
+  WeakHandle w(Universe::vm_weak(), protection_domain);
   ProtectionDomainCacheEntry* p = new_entry(hash, w);
   Hashtable<WeakHandle, mtClass>::add_entry(index, p);
   return p;

src/hotspot/share/classfile/stringTable.cpp

@@ -85,8 +85,7 @@ static StringTableHash* _local_table = NULL;
 
 volatile bool StringTable::_has_work = false;
 volatile bool StringTable::_needs_rehashing = false;
-
-volatile size_t StringTable::_uncleaned_items_count = 0;
+OopStorage*   StringTable::_oop_storage;
 
 static size_t _current_size = 0;
 static volatile size_t _items_count = 0;
@@ -129,7 +128,7 @@ class StringTableConfig : public StackObj {
     return AllocateHeap(size, mtSymbol);
   }
   static void free_node(void* memory, Value const& value) {
-    value.release(OopStorageSet::string_table_weak());
+    value.release(StringTable::_oop_storage);
     FreeHeap(memory);
     StringTable::item_removed();
   }
@@ -211,30 +210,24 @@ void StringTable::create_table() {
   log_trace(stringtable)("Start size: " SIZE_FORMAT " (" SIZE_FORMAT ")",
                          _current_size, start_size_log_2);
   _local_table = new StringTableHash(start_size_log_2, END_SIZE, REHASH_LEN);
+  _oop_storage = OopStorageSet::create_weak("StringTable Weak");
+  _oop_storage->register_num_dead_callback(&gc_notification);
 }
 
 size_t StringTable::item_added() {
   return Atomic::add(&_items_count, (size_t)1);
 }
 
-size_t StringTable::add_items_to_clean(size_t ndead) {
-  size_t total = Atomic::add(&_uncleaned_items_count, (size_t)ndead);
-  log_trace(stringtable)(
-     "Uncleaned items:" SIZE_FORMAT " added: " SIZE_FORMAT " total:" SIZE_FORMAT,
-     _uncleaned_items_count, ndead, total);
-  return total;
-}
-
 void StringTable::item_removed() {
   Atomic::add(&_items_count, (size_t)-1);
 }
 
 double StringTable::get_load_factor() {
-  return (double)_items_count/_current_size;
+  return double(_items_count)/double(_current_size);
 }
 
-double StringTable::get_dead_factor() {
-  return (double)_uncleaned_items_count/_current_size;
+double StringTable::get_dead_factor(size_t num_dead) {
+  return double(num_dead)/double(_current_size);
 }
 
 size_t StringTable::table_size() {
@@ -243,7 +236,7 @@ size_t StringTable::table_size() {
 
 void StringTable::trigger_concurrent_work() {
   MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
-  _has_work = true;
+  Atomic::store(&_has_work, true);
   Service_lock->notify_all();
 }
 
@@ -368,7 +361,7 @@ oop StringTable::do_intern(Handle string_or_null_h, const jchar* name,
   bool rehash_warning;
   do {
     // Callers have already looked up the String using the jchar* name, so just go to add.
-    WeakHandle wh(OopStorageSet::string_table_weak(), string_h);
+    WeakHandle wh(_oop_storage, string_h);
     // The hash table takes ownership of the WeakHandle, even if it's not inserted.
     if (_local_table->insert(THREAD, lookup, wh, &rehash_warning)) {
       update_needs_rehash(rehash_warning);
@@ -449,13 +442,15 @@ void StringTable::clean_dead_entries(JavaThread* jt) {
   log_debug(stringtable)("Cleaned %ld of %ld", stdc._count, stdc._item);
 }
 
-void StringTable::check_concurrent_work() {
-  if (_has_work) {
+void StringTable::gc_notification(size_t num_dead) {
+  log_trace(stringtable)("Uncleaned items:" SIZE_FORMAT, num_dead);
+
+  if (has_work()) {
     return;
   }
 
   double load_factor = StringTable::get_load_factor();
-  double dead_factor = StringTable::get_dead_factor();
+  double dead_factor = StringTable::get_dead_factor(num_dead);
   // We should clean/resize if we have more dead than alive,
   // more items than preferred load factor or
   // more dead items than water mark.
@@ -468,8 +463,11 @@ void StringTable::check_concurrent_work() {
   }
 }
 
+bool StringTable::has_work() {
+  return Atomic::load_acquire(&_has_work);
+}
+
 void StringTable::do_concurrent_work(JavaThread* jt) {
-  _has_work = false;
   double load_factor = get_load_factor();
   log_debug(stringtable, perf)("Concurrent work, live factor: %g", load_factor);
   // We prefer growing, since that also removes dead items
@@ -478,6 +476,7 @@ void StringTable::do_concurrent_work(JavaThread* jt) {
   } else {
     clean_dead_entries(jt);
   }
+  Atomic::release_store(&_has_work, false);
 }
 
 // Rehash

src/hotspot/share/classfile/stringTable.hpp

@@ -46,23 +46,26 @@ class StringTable : public CHeapObj<mtSymbol>{
   friend class StringTableCreateEntry;
 
   static volatile bool _has_work;
-  static volatile size_t _uncleaned_items_count;
 
   // Set if one bucket is out of balance due to hash algorithm deficiency
   static volatile bool _needs_rehashing;
 
+  static OopStorage* _oop_storage;
+
   static void grow(JavaThread* jt);
   static void clean_dead_entries(JavaThread* jt);
 
   static double get_load_factor();
-  static double get_dead_factor();
+  static double get_dead_factor(size_t num_dead);
+
+  // GC support
 
-  static void check_concurrent_work();
+  // Callback for GC to notify of changes that might require cleaning or resize.
+  static void gc_notification(size_t num_dead);
   static void trigger_concurrent_work();
 
   static size_t item_added();
   static void item_removed();
-  static size_t add_items_to_clean(size_t ndead);
 
   static oop intern(Handle string_or_null_h, const jchar* name, int len, TRAPS);
   static oop do_intern(Handle string_or_null, const jchar* name, int len, uintx hash, TRAPS);
@@ -79,20 +82,7 @@ class StringTable : public CHeapObj<mtSymbol>{
   static void create_table();
 
   static void do_concurrent_work(JavaThread* jt);
-  static bool has_work() { return _has_work; }
-
-  // GC support
-
-  // Must be called before a parallel walk where strings might die.
-  static void reset_dead_counter() { _uncleaned_items_count = 0; }
-
-  // After the parallel walk this method must be called to trigger
-  // cleaning. Note it might trigger a resize instead.
-  static void finish_dead_counter() { check_concurrent_work(); }
-
-  // If GC uses ParState directly it should add the number of cleared
-  // strings to this method.
-  static void inc_dead_counter(size_t ndead) { add_items_to_clean(ndead); }
+  static bool has_work();
 
   // Probing
   static oop lookup(Symbol* symbol);

src/hotspot/share/classfile/systemDictionary.cpp

@@ -176,15 +176,15 @@ void SystemDictionary::compute_java_loaders(TRAPS) {
                          vmSymbols::void_classloader_signature(),
                          CHECK);
 
-  _java_system_loader = OopHandle(OopStorageSet::vm_global(), (oop)result.get_jobject());
+  _java_system_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
 
   JavaCalls::call_static(&result,
                          class_loader_klass,
                          vmSymbols::getPlatformClassLoader_name(),
                          vmSymbols::void_classloader_signature(),
                          CHECK);
 
-  _java_platform_loader = OopHandle(OopStorageSet::vm_global(), (oop)result.get_jobject());
+  _java_platform_loader = OopHandle(Universe::vm_global(), (oop)result.get_jobject());
 }
 
 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
@@ -2030,7 +2030,7 @@ void SystemDictionary::initialize(TRAPS) {
 
   // Allocate private object used as system class loader lock
   oop lock_obj = oopFactory::new_intArray(0, CHECK);
-  _system_loader_lock_obj = OopHandle(OopStorageSet::vm_global(), lock_obj);
+  _system_loader_lock_obj = OopHandle(Universe::vm_global(), lock_obj);
 
   // Initialize basic classes
   resolve_well_known_classes(CHECK);

src/hotspot/share/classfile/systemDictionaryShared.cpp

@@ -1023,23 +1023,23 @@ void SystemDictionaryShared::allocate_shared_protection_domain_array(int size, T
   if (_shared_protection_domains.resolve() == NULL) {
     oop spd = oopFactory::new_objArray(
         SystemDictionary::ProtectionDomain_klass(), size, CHECK);
-    _shared_protection_domains = OopHandle(OopStorageSet::vm_global(), spd);
+    _shared_protection_domains = OopHandle(Universe::vm_global(), spd);
   }
 }
 
 void SystemDictionaryShared::allocate_shared_jar_url_array(int size, TRAPS) {
   if (_shared_jar_urls.resolve() == NULL) {
     oop sju = oopFactory::new_objArray(
         SystemDictionary::URL_klass(), size, CHECK);
-    _shared_jar_urls = OopHandle(OopStorageSet::vm_global(), sju);
+    _shared_jar_urls = OopHandle(Universe::vm_global(), sju);
   }
 }
 
 void SystemDictionaryShared::allocate_shared_jar_manifest_array(int size, TRAPS) {
   if (_shared_jar_manifests.resolve() == NULL) {
     oop sjm = oopFactory::new_objArray(
         SystemDictionary::Jar_Manifest_klass(), size, CHECK);
-    _shared_jar_manifests = OopHandle(OopStorageSet::vm_global(), sjm);
+    _shared_jar_manifests = OopHandle(Universe::vm_global(), sjm);
   }
 }
 

src/hotspot/share/gc/g1/g1Policy.cpp

@@ -77,7 +77,8 @@ G1Policy::G1Policy(STWGCTimer* gc_timer) :
   _concurrent_start_to_mixed(),
   _collection_set(NULL),
   _g1h(NULL),
-  _phase_times(new G1GCPhaseTimes(gc_timer, ParallelGCThreads)),
+  _phase_times_timer(gc_timer),
+  _phase_times(NULL),
   _mark_remark_start_sec(0),
   _mark_cleanup_start_sec(0),
   _tenuring_threshold(MaxTenuringThreshold),
@@ -401,6 +402,15 @@ double G1Policy::predict_survivor_regions_evac_time() const {
   return survivor_regions_evac_time;
 }
 
+G1GCPhaseTimes* G1Policy::phase_times() const {
+  // Lazy allocation because it must follow initialization of all the
+  // OopStorage objects by various other subsystems.
+  if (_phase_times == NULL) {
+    _phase_times = new G1GCPhaseTimes(_phase_times_timer, ParallelGCThreads);
+  }
+  return _phase_times;
+}
+
 void G1Policy::revise_young_list_target_length_if_necessary(size_t rs_length) {
   guarantee(use_adaptive_young_list_length(), "should not call this otherwise" );
 

src/hotspot/share/gc/g1/g1Policy.hpp

@@ -182,7 +182,9 @@ class G1Policy: public CHeapObj<mtGC> {
   // Stash a pointer to the g1 heap.
   G1CollectedHeap* _g1h;
 
-  G1GCPhaseTimes* _phase_times;
+  STWGCTimer*     _phase_times_timer;
+  // Lazily initialized
+  mutable G1GCPhaseTimes* _phase_times;
 
   // This set of variables tracks the collector efficiency, in order to
   // determine whether we should initiate a new marking.
@@ -300,7 +302,7 @@ class G1Policy: public CHeapObj<mtGC> {
 
   G1CollectorState* collector_state() const;
 
-  G1GCPhaseTimes* phase_times() const { return _phase_times; }
+  G1GCPhaseTimes* phase_times() const;
 
   // Check the current value of the young list RSet length and
   // compare it against the last prediction. If the current value is

src/hotspot/share/gc/shared/oopStorage.cpp

@@ -746,6 +746,7 @@ OopStorage::OopStorage(const char* name) :
   _deferred_updates(NULL),
   _allocation_mutex(make_oopstorage_mutex(name, "alloc", Mutex::oopstorage)),
   _active_mutex(make_oopstorage_mutex(name, "active", Mutex::oopstorage - 1)),
+  _num_dead_callback(NULL),
   _allocation_count(0),
   _concurrent_iteration_count(0),
   _needs_cleanup(false)
@@ -814,6 +815,21 @@ static jlong cleanup_trigger_permit_time = 0;
 // too frequent.
 const jlong cleanup_trigger_defer_period = 500 * NANOSECS_PER_MILLISEC;
 
+void OopStorage::register_num_dead_callback(NumDeadCallback f) {
+  assert(_num_dead_callback == NULL, "Only one callback function supported");
+  _num_dead_callback = f;
+}
+
+void OopStorage::report_num_dead(size_t num_dead) const {
+  if (_num_dead_callback != NULL) {
+    _num_dead_callback(num_dead);
+  }
+}
+
+bool OopStorage::should_report_num_dead() const {
+  return _num_dead_callback != NULL;
+}
+
 void OopStorage::trigger_cleanup_if_needed() {
   MonitorLocker ml(Service_lock, Monitor::_no_safepoint_check_flag);
   if (Atomic::load(&needs_cleanup_requested) &&
@@ -970,7 +986,8 @@ OopStorage::BasicParState::BasicParState(const OopStorage* storage,
   _block_count(0),              // initialized properly below
   _next_block(0),
   _estimated_thread_count(estimated_thread_count),
-  _concurrent(concurrent)
+  _concurrent(concurrent),
+  _num_dead(0)
 {
   assert(estimated_thread_count > 0, "estimated thread count must be positive");
   update_concurrent_iteration_count(1);
@@ -1043,6 +1060,18 @@ bool OopStorage::BasicParState::finish_iteration(const IterationData* data) cons
   return false;
 }
 
+size_t OopStorage::BasicParState::num_dead() const {
+  return Atomic::load(&_num_dead);
+}
+
+void OopStorage::BasicParState::increment_num_dead(size_t num_dead) {
+  Atomic::add(&_num_dead, num_dead);
+}
+
+void OopStorage::BasicParState::report_num_dead() const {
+  _storage->report_num_dead(Atomic::load(&_num_dead));
+}
+
 const char* OopStorage::name() const { return _name; }
 
 #ifndef PRODUCT