| /* |
| * Copyright (c) 2003, 2019, 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 |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "classfile/altHashing.hpp" |
| #include "classfile/dictionary.hpp" |
| #include "classfile/javaClasses.inline.hpp" |
| #include "classfile/moduleEntry.hpp" |
| #include "classfile/packageEntry.hpp" |
| #include "classfile/placeholders.hpp" |
| #include "classfile/protectionDomainCache.hpp" |
| #include "classfile/stringTable.hpp" |
| #include "code/nmethod.hpp" |
| #include "logging/log.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "oops/weakHandle.inline.hpp" |
| #include "runtime/safepoint.hpp" |
| #include "utilities/dtrace.hpp" |
| #include "utilities/hashtable.hpp" |
| #include "utilities/hashtable.inline.hpp" |
| #include "utilities/numberSeq.hpp" |
| |
| |
| // This hashtable is implemented as an open hash table with a fixed number of buckets. |
| |
| template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry_free_list() { |
| BasicHashtableEntry<F>* entry = NULL; |
| if (_free_list != NULL) { |
| entry = _free_list; |
| _free_list = _free_list->next(); |
| } |
| return entry; |
| } |
| |
| // HashtableEntrys are allocated in blocks to reduce the space overhead. |
| template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry(unsigned int hashValue) { |
| BasicHashtableEntry<F>* entry = new_entry_free_list(); |
| |
| if (entry == NULL) { |
| if (_first_free_entry + _entry_size >= _end_block) { |
| int block_size = MAX2((int)_table_size / 2, (int)_number_of_entries); // pick a reasonable value |
| block_size = clamp(block_size, 2, 512); // but never go out of this range |
| int len = _entry_size * block_size; |
| len = 1 << log2_int(len); // round down to power of 2 |
| assert(len >= _entry_size, ""); |
| _first_free_entry = NEW_C_HEAP_ARRAY2(char, len, F, CURRENT_PC); |
| _entry_blocks.append(_first_free_entry); |
| _end_block = _first_free_entry + len; |
| } |
| entry = (BasicHashtableEntry<F>*)_first_free_entry; |
| _first_free_entry += _entry_size; |
| } |
| |
| assert(_entry_size % HeapWordSize == 0, ""); |
| entry->set_hash(hashValue); |
| return entry; |
| } |
| |
| |
| template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) { |
| HashtableEntry<T, F>* entry; |
| |
| entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue); |
| entry->set_literal(obj); |
| return entry; |
| } |
| |
| // Version of hashtable entry allocation that allocates in the C heap directly. |
| // The block allocator in BasicHashtable has less fragmentation, but the memory is not freed until |
| // the whole table is freed. Use allocate_new_entry() if you want to individually free the memory |
| // used by each entry |
| template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::allocate_new_entry(unsigned int hashValue, T obj) { |
| HashtableEntry<T, F>* entry = (HashtableEntry<T, F>*) NEW_C_HEAP_ARRAY(char, this->entry_size(), F); |
| |
| entry->set_hash(hashValue); |
| entry->set_literal(obj); |
| entry->set_next(NULL); |
| return entry; |
| } |
| |
| template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() { |
| FREE_C_HEAP_ARRAY(HashtableBucket, _buckets); |
| _buckets = NULL; |
| } |
| |
| // For oops and Strings the size of the literal is interesting. For other types, nobody cares. |
| static int literal_size(ConstantPool*) { return 0; } |
| static int literal_size(Klass*) { return 0; } |
| static int literal_size(nmethod*) { return 0; } |
| |
| static int literal_size(Symbol *symbol) { |
| return symbol->size() * HeapWordSize; |
| } |
| |
| static int literal_size(oop obj) { |
| // NOTE: this would over-count if (pre-JDK8) java_lang_Class::has_offset_field() is true, |
| // and the String.value array is shared by several Strings. However, starting from JDK8, |
| // the String.value array is not shared anymore. |
| if (obj == NULL) { |
| return 0; |
| } else if (obj->klass() == SystemDictionary::String_klass()) { |
| return (obj->size() + java_lang_String::value(obj)->size()) * HeapWordSize; |
| } else { |
| return obj->size(); |
| } |
| } |
| |
| static int literal_size(WeakHandle v) { |
| return literal_size(v.peek()); |
| } |
| |
| template <MEMFLAGS F> bool BasicHashtable<F>::resize(int new_size) { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| |
| // Allocate new buckets |
| HashtableBucket<F>* buckets_new = NEW_C_HEAP_ARRAY2_RETURN_NULL(HashtableBucket<F>, new_size, F, CURRENT_PC); |
| if (buckets_new == NULL) { |
| return false; |
| } |
| |
| // Clear the new buckets |
| for (int i = 0; i < new_size; i++) { |
| buckets_new[i].clear(); |
| } |
| |
| int table_size_old = _table_size; |
| // hash_to_index() uses _table_size, so switch the sizes now |
| _table_size = new_size; |
| |
| // Move entries from the old table to a new table |
| for (int index_old = 0; index_old < table_size_old; index_old++) { |
| for (BasicHashtableEntry<F>* p = _buckets[index_old].get_entry(); p != NULL; ) { |
| BasicHashtableEntry<F>* next = p->next(); |
| bool keep_shared = p->is_shared(); |
| int index_new = hash_to_index(p->hash()); |
| |
| p->set_next(buckets_new[index_new].get_entry()); |
| buckets_new[index_new].set_entry(p); |
| |
| if (keep_shared) { |
| p->set_shared(); |
| } |
| p = next; |
| } |
| } |
| |
| // The old backets now can be released |
| BasicHashtable<F>::free_buckets(); |
| |
| // Switch to the new storage |
| _buckets = buckets_new; |
| |
| return true; |
| } |
| |
| template <MEMFLAGS F> bool BasicHashtable<F>::maybe_grow(int max_size, int load_factor) { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); |
| |
| if (table_size() >= max_size) { |
| return false; |
| } |
| if (number_of_entries() / table_size() > load_factor) { |
| resize(MIN2<int>(table_size() * 2, max_size)); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| template <class T, MEMFLAGS F> TableStatistics Hashtable<T, F>::statistics_calculate(T (*literal_load_barrier)(HashtableEntry<T, F>*)) { |
| NumberSeq summary; |
| int literal_bytes = 0; |
| for (int i = 0; i < this->table_size(); ++i) { |
| int count = 0; |
| for (HashtableEntry<T, F>* e = this->bucket(i); |
| e != NULL; e = e->next()) { |
| count++; |
| T l = (literal_load_barrier != NULL) ? literal_load_barrier(e) : e->literal(); |
| literal_bytes += literal_size(l); |
| } |
| summary.add((double)count); |
| } |
| return TableStatistics(this->_stats_rate, summary, literal_bytes, sizeof(HashtableBucket<F>), sizeof(HashtableEntry<T, F>)); |
| } |
| |
| // Dump footprint and bucket length statistics |
| // |
| // Note: if you create a new subclass of Hashtable<MyNewType, F>, you will need to |
| // add a new function static int literal_size(MyNewType lit) |
| // because I can't get template <class T> int literal_size(T) to pick the specializations for Symbol and oop. |
| template <class T, MEMFLAGS F> void Hashtable<T, F>::print_table_statistics(outputStream* st, |
| const char *table_name, |
| T (*literal_load_barrier)(HashtableEntry<T, F>*)) { |
| TableStatistics ts = statistics_calculate(literal_load_barrier); |
| ts.print(st, table_name); |
| } |
| |
| #ifndef PRODUCT |
| template <class T> void print_literal(T l) { |
| l->print(); |
| } |
| |
| static void print_literal(WeakHandle l) { |
| l.print(); |
| } |
| |
| template <class T, MEMFLAGS F> void Hashtable<T, F>::print() { |
| ResourceMark rm; |
| |
| for (int i = 0; i < BasicHashtable<F>::table_size(); i++) { |
| HashtableEntry<T, F>* entry = bucket(i); |
| while(entry != NULL) { |
| tty->print("%d : ", i); |
| print_literal(entry->literal()); |
| tty->cr(); |
| entry = entry->next(); |
| } |
| } |
| } |
| |
| template <MEMFLAGS F> |
| template <class T> void BasicHashtable<F>::verify_table(const char* table_name) { |
| int element_count = 0; |
| int max_bucket_count = 0; |
| int max_bucket_number = 0; |
| for (int index = 0; index < table_size(); index++) { |
| int bucket_count = 0; |
| for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) { |
| probe->verify(); |
| bucket_count++; |
| } |
| element_count += bucket_count; |
| if (bucket_count > max_bucket_count) { |
| max_bucket_count = bucket_count; |
| max_bucket_number = index; |
| } |
| } |
| guarantee(number_of_entries() == element_count, |
| "Verify of %s failed", table_name); |
| |
| // Log some statistics about the hashtable |
| log_info(hashtables)("%s max bucket size %d bucket %d element count %d table size %d", table_name, |
| max_bucket_count, max_bucket_number, _number_of_entries, _table_size); |
| if (_number_of_entries > 0 && log_is_enabled(Debug, hashtables)) { |
| for (int index = 0; index < table_size(); index++) { |
| int bucket_count = 0; |
| for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) { |
| log_debug(hashtables)("bucket %d hash " INTPTR_FORMAT, index, (intptr_t)probe->hash()); |
| bucket_count++; |
| } |
| if (bucket_count > 0) { |
| log_debug(hashtables)("bucket %d count %d", index, bucket_count); |
| } |
| } |
| } |
| } |
| #endif // PRODUCT |
| |
| // Explicitly instantiate these types |
| template class Hashtable<nmethod*, mtGC>; |
| template class HashtableEntry<nmethod*, mtGC>; |
| template class BasicHashtable<mtGC>; |
| template class Hashtable<ConstantPool*, mtClass>; |
| template class Hashtable<Symbol*, mtSymbol>; |
| template class Hashtable<Klass*, mtClass>; |
| template class Hashtable<InstanceKlass*, mtClass>; |
| template class Hashtable<WeakHandle, mtClass>; |
| template class Hashtable<Symbol*, mtModule>; |
| template class Hashtable<oop, mtSymbol>; |
| template class Hashtable<Symbol*, mtClass>; |
| template class HashtableEntry<Symbol*, mtSymbol>; |
| template class HashtableEntry<Symbol*, mtClass>; |
| template class HashtableEntry<oop, mtSymbol>; |
| template class HashtableBucket<mtClass>; |
| template class BasicHashtableEntry<mtSymbol>; |
| template class BasicHashtableEntry<mtCode>; |
| template class BasicHashtable<mtClass>; |
| template class BasicHashtable<mtClassShared>; |
| template class BasicHashtable<mtSymbol>; |
| template class BasicHashtable<mtCode>; |
| template class BasicHashtable<mtInternal>; |
| template class BasicHashtable<mtModule>; |
| template class BasicHashtable<mtCompiler>; |
| template class BasicHashtable<mtTracing>; |
| |
| template void BasicHashtable<mtClass>::verify_table<DictionaryEntry>(char const*); |
| template void BasicHashtable<mtModule>::verify_table<ModuleEntry>(char const*); |
| template void BasicHashtable<mtModule>::verify_table<PackageEntry>(char const*); |
| template void BasicHashtable<mtClass>::verify_table<ProtectionDomainCacheEntry>(char const*); |
| template void BasicHashtable<mtClass>::verify_table<PlaceholderEntry>(char const*); |