annotate src/hotspot/share/utilities/hashtable.cpp @ 53482:f4e3900c8d08

8213346: Re-implement shared dictionary using CompactHashtable Reviewed-by: jiangli
author iklam
date Wed, 07 Nov 2018 19:40:27 -0800
parents 1fc8166e28a2
children 3009ca99de32
rev   line source
duke@1 1 /*
coleenp@50313 2 * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
duke@1 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1 4 *
duke@1 5 * This code is free software; you can redistribute it and/or modify it
duke@1 6 * under the terms of the GNU General Public License version 2 only, as
duke@1 7 * published by the Free Software Foundation.
duke@1 8 *
duke@1 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@1 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@1 13 * accompanied this code).
duke@1 14 *
duke@1 15 * You should have received a copy of the GNU General Public License version
duke@1 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@1 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1 18 *
trims@5547 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@5547 20 * or visit www.oracle.com if you need additional information or have any
trims@5547 21 * questions.
duke@1 22 *
duke@1 23 */
duke@1 24
stefank@7397 25 #include "precompiled.hpp"
coleenp@13199 26 #include "classfile/altHashing.hpp"
coleenp@46475 27 #include "classfile/dictionary.hpp"
goetz@35498 28 #include "classfile/javaClasses.inline.hpp"
coleenp@46475 29 #include "classfile/moduleEntry.hpp"
coleenp@46475 30 #include "classfile/packageEntry.hpp"
coleenp@46545 31 #include "classfile/placeholders.hpp"
coleenp@46475 32 #include "classfile/protectionDomainCache.hpp"
gziemski@24426 33 #include "classfile/stringTable.hpp"
stefank@50518 34 #include "logging/log.hpp"
stefank@7397 35 #include "memory/allocation.inline.hpp"
stefank@7397 36 #include "memory/resourceArea.hpp"
stefank@7397 37 #include "oops/oop.inline.hpp"
coleenp@50313 38 #include "oops/weakHandle.inline.hpp"
stefank@7397 39 #include "runtime/safepoint.hpp"
stefank@7397 40 #include "utilities/dtrace.hpp"
stefank@7397 41 #include "utilities/hashtable.hpp"
stefank@7397 42 #include "utilities/hashtable.inline.hpp"
iklam@17610 43 #include "utilities/numberSeq.hpp"
duke@1 44
coleenp@8076 45
mgerdin@26421 46 // This hashtable is implemented as an open hash table with a fixed number of buckets.
duke@1 47
mgerdin@26421 48 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry_free_list() {
mgerdin@26421 49 BasicHashtableEntry<F>* entry = NULL;
mgerdin@26421 50 if (_free_list != NULL) {
duke@1 51 entry = _free_list;
duke@1 52 _free_list = _free_list->next();
mgerdin@26421 53 }
mgerdin@26421 54 return entry;
mgerdin@26421 55 }
mgerdin@26421 56
mgerdin@26421 57 // HashtableEntrys are allocated in blocks to reduce the space overhead.
mgerdin@26421 58 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry(unsigned int hashValue) {
mgerdin@26421 59 BasicHashtableEntry<F>* entry = new_entry_free_list();
mgerdin@26421 60
mgerdin@26421 61 if (entry == NULL) {
jrose@1551 62 if (_first_free_entry + _entry_size >= _end_block) {
jrose@1551 63 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries));
duke@1 64 int len = _entry_size * block_size;
jrose@1551 65 len = 1 << log2_intptr(len); // round down to power of 2
jrose@1551 66 assert(len >= _entry_size, "");
zgu@13195 67 _first_free_entry = NEW_C_HEAP_ARRAY2(char, len, F, CURRENT_PC);
duke@1 68 _end_block = _first_free_entry + len;
duke@1 69 }
zgu@13195 70 entry = (BasicHashtableEntry<F>*)_first_free_entry;
duke@1 71 _first_free_entry += _entry_size;
duke@1 72 }
duke@1 73
jrose@1551 74 assert(_entry_size % HeapWordSize == 0, "");
duke@1 75 entry->set_hash(hashValue);
duke@1 76 return entry;
duke@1 77 }
duke@1 78
duke@1 79
zgu@13195 80 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) {
zgu@13195 81 HashtableEntry<T, F>* entry;
duke@1 82
zgu@13195 83 entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue);
coleenp@8076 84 entry->set_literal(obj);
duke@1 85 return entry;
duke@1 86 }
duke@1 87
coleenp@46729 88 // Version of hashtable entry allocation that allocates in the C heap directly.
coleenp@46729 89 // The allocator in blocks is preferable but doesn't have free semantics.
coleenp@46729 90 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::allocate_new_entry(unsigned int hashValue, T obj) {
coleenp@46729 91 HashtableEntry<T, F>* entry = (HashtableEntry<T, F>*) NEW_C_HEAP_ARRAY(char, this->entry_size(), F);
coleenp@46729 92
coleenp@46729 93 entry->set_hash(hashValue);
coleenp@46729 94 entry->set_literal(obj);
coleenp@46729 95 entry->set_next(NULL);
coleenp@46729 96 return entry;
coleenp@46729 97 }
coleenp@46729 98
zgu@13195 99 template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() {
coleenp@13097 100 if (NULL != _buckets) {
iklam@53482 101 FREE_C_HEAP_ARRAY(HashtableBucket, _buckets);
coleenp@13097 102 _buckets = NULL;
coleenp@13097 103 }
coleenp@13097 104 }
coleenp@13097 105
tschatzl@45114 106 template <MEMFLAGS F> void BasicHashtable<F>::BucketUnlinkContext::free_entry(BasicHashtableEntry<F>* entry) {
tschatzl@45114 107 entry->set_next(_removed_head);
tschatzl@45114 108 _removed_head = entry;
tschatzl@45114 109 if (_removed_tail == NULL) {
tschatzl@45114 110 _removed_tail = entry;
tschatzl@45114 111 }
tschatzl@45114 112 _num_removed++;
tschatzl@45114 113 }
tschatzl@45114 114
tschatzl@45114 115 template <MEMFLAGS F> void BasicHashtable<F>::bulk_free_entries(BucketUnlinkContext* context) {
tschatzl@45114 116 if (context->_num_removed == 0) {
tschatzl@45114 117 assert(context->_removed_head == NULL && context->_removed_tail == NULL,
tschatzl@45114 118 "Zero entries in the unlink context, but elements linked from " PTR_FORMAT " to " PTR_FORMAT,
tschatzl@45114 119 p2i(context->_removed_head), p2i(context->_removed_tail));
tschatzl@45114 120 return;
tschatzl@45114 121 }
tschatzl@45114 122
tschatzl@45114 123 // MT-safe add of the list of BasicHashTableEntrys from the context to the free list.
tschatzl@45114 124 BasicHashtableEntry<F>* current = _free_list;
tschatzl@45114 125 while (true) {
tschatzl@45114 126 context->_removed_tail->set_next(current);
coleenp@47789 127 BasicHashtableEntry<F>* old = Atomic::cmpxchg(context->_removed_head, &_free_list, current);
tschatzl@45114 128 if (old == current) {
tschatzl@45114 129 break;
tschatzl@45114 130 }
tschatzl@45114 131 current = old;
tschatzl@45114 132 }
tschatzl@45114 133 Atomic::add(-context->_num_removed, &_number_of_entries);
tschatzl@45114 134 }
duke@1 135
coleenp@46742 136 // For oops and Strings the size of the literal is interesting. For other types, nobody cares.
coleenp@46742 137 static int literal_size(ConstantPool*) { return 0; }
coleenp@46742 138 static int literal_size(Klass*) { return 0; }
coleenp@46742 139 static int literal_size(nmethod*) { return 0; }
coleenp@46742 140
coleenp@46742 141 static int literal_size(Symbol *symbol) {
iklam@17610 142 return symbol->size() * HeapWordSize;
iklam@17610 143 }
iklam@17610 144
coleenp@46742 145 static int literal_size(oop obj) {
iklam@17610 146 // NOTE: this would over-count if (pre-JDK8) java_lang_Class::has_offset_field() is true,
iklam@17610 147 // and the String.value array is shared by several Strings. However, starting from JDK8,
iklam@17610 148 // the String.value array is not shared anymore.
coleenp@46742 149 if (obj == NULL) {
coleenp@46742 150 return 0;
coleenp@46742 151 } else if (obj->klass() == SystemDictionary::String_klass()) {
coleenp@46742 152 return (obj->size() + java_lang_String::value(obj)->size()) * HeapWordSize;
coleenp@46742 153 } else {
coleenp@46742 154 return obj->size();
coleenp@46742 155 }
iklam@17610 156 }
iklam@17610 157
coleenp@50313 158 static int literal_size(ClassLoaderWeakHandle v) {
coleenp@50313 159 return literal_size(v.peek());
coleenp@50313 160 }
coleenp@50313 161
gziemski@47955 162 template <MEMFLAGS F> bool BasicHashtable<F>::resize(int new_size) {
gziemski@47955 163 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
gziemski@47955 164
gziemski@47955 165 // Allocate new buckets
gziemski@47955 166 HashtableBucket<F>* buckets_new = NEW_C_HEAP_ARRAY2_RETURN_NULL(HashtableBucket<F>, new_size, F, CURRENT_PC);
gziemski@47955 167 if (buckets_new == NULL) {
gziemski@47955 168 return false;
gziemski@47955 169 }
gziemski@47955 170
gziemski@47955 171 // Clear the new buckets
gziemski@47955 172 for (int i = 0; i < new_size; i++) {
gziemski@47955 173 buckets_new[i].clear();
gziemski@47955 174 }
gziemski@47955 175
gziemski@47955 176 int table_size_old = _table_size;
gziemski@47955 177 // hash_to_index() uses _table_size, so switch the sizes now
gziemski@47955 178 _table_size = new_size;
gziemski@47955 179
gziemski@47955 180 // Move entries from the old table to a new table
gziemski@47955 181 for (int index_old = 0; index_old < table_size_old; index_old++) {
gziemski@47955 182 for (BasicHashtableEntry<F>* p = _buckets[index_old].get_entry(); p != NULL; ) {
gziemski@47955 183 BasicHashtableEntry<F>* next = p->next();
gziemski@47955 184 bool keep_shared = p->is_shared();
gziemski@47955 185 int index_new = hash_to_index(p->hash());
gziemski@47955 186
gziemski@47955 187 p->set_next(buckets_new[index_new].get_entry());
gziemski@47955 188 buckets_new[index_new].set_entry(p);
gziemski@47955 189
gziemski@47955 190 if (keep_shared) {
gziemski@47955 191 p->set_shared();
gziemski@47955 192 }
gziemski@47955 193 p = next;
gziemski@47955 194 }
gziemski@47955 195 }
gziemski@47955 196
gziemski@47955 197 // The old backets now can be released
gziemski@47955 198 BasicHashtable<F>::free_buckets();
gziemski@47955 199
gziemski@47955 200 // Switch to the new storage
gziemski@47955 201 _buckets = buckets_new;
gziemski@47955 202
gziemski@47955 203 return true;
gziemski@47955 204 }
coleenp@46742 205
iklam@17610 206 // Dump footprint and bucket length statistics
iklam@17610 207 //
iklam@17610 208 // Note: if you create a new subclass of Hashtable<MyNewType, F>, you will need to
coleenp@46742 209 // add a new function static int literal_size(MyNewType lit)
coleenp@46742 210 // because I can't get template <class T> int literal_size(T) to pick the specializations for Symbol and oop.
coleenp@46742 211 //
coleenp@46742 212 // The StringTable and SymbolTable dumping print how much footprint is used by the String and Symbol
coleenp@46742 213 // literals.
iklam@17610 214
coleenp@46742 215 template <class T, MEMFLAGS F> void Hashtable<T, F>::print_table_statistics(outputStream* st,
stefank@50817 216 const char *table_name,
stefank@50817 217 T (*literal_load_barrier)(HashtableEntry<T, F>*)) {
iklam@17610 218 NumberSeq summary;
iklam@17610 219 int literal_bytes = 0;
iklam@17610 220 for (int i = 0; i < this->table_size(); ++i) {
iklam@17610 221 int count = 0;
mgerdin@26421 222 for (HashtableEntry<T, F>* e = this->bucket(i);
iklam@46746 223 e != NULL; e = e->next()) {
iklam@17610 224 count++;
stefank@50817 225 T l = (literal_load_barrier != NULL) ? literal_load_barrier(e) : e->literal();
stefank@50817 226 literal_bytes += literal_size(l);
iklam@17610 227 }
iklam@17610 228 summary.add((double)count);
iklam@17610 229 }
iklam@17610 230 double num_buckets = summary.num();
iklam@17610 231 double num_entries = summary.sum();
iklam@17610 232
mgerdin@26421 233 int bucket_bytes = (int)num_buckets * sizeof(HashtableBucket<F>);
iklam@17610 234 int entry_bytes = (int)num_entries * sizeof(HashtableEntry<T, F>);
iklam@17610 235 int total_bytes = literal_bytes + bucket_bytes + entry_bytes;
iklam@17610 236
coleenp@46742 237 int bucket_size = (num_buckets <= 0) ? 0 : (bucket_bytes / num_buckets);
coleenp@46742 238 int entry_size = (num_entries <= 0) ? 0 : (entry_bytes / num_entries);
iklam@17610 239
iklam@17610 240 st->print_cr("%s statistics:", table_name);
coleenp@46742 241 st->print_cr("Number of buckets : %9d = %9d bytes, each %d", (int)num_buckets, bucket_bytes, bucket_size);
coleenp@46742 242 st->print_cr("Number of entries : %9d = %9d bytes, each %d", (int)num_entries, entry_bytes, entry_size);
coleenp@46742 243 if (literal_bytes != 0) {
coleenp@46742 244 double literal_avg = (num_entries <= 0) ? 0 : (literal_bytes / num_entries);
coleenp@46742 245 st->print_cr("Number of literals : %9d = %9d bytes, avg %7.3f", (int)num_entries, literal_bytes, literal_avg);
coleenp@46742 246 }
iklam@17610 247 st->print_cr("Total footprint : %9s = %9d bytes", "", total_bytes);
iklam@17610 248 st->print_cr("Average bucket size : %9.3f", summary.avg());
iklam@17610 249 st->print_cr("Variance of bucket size : %9.3f", summary.variance());
iklam@17610 250 st->print_cr("Std. dev. of bucket size: %9.3f", summary.sd());
iklam@17610 251 st->print_cr("Maximum bucket size : %9d", (int)summary.maximum());
iklam@17610 252 }
iklam@17610 253
duke@1 254 #ifndef PRODUCT
coleenp@50313 255 template <class T> void print_literal(T l) {
coleenp@50313 256 l->print();
coleenp@50313 257 }
coleenp@50313 258
coleenp@50313 259 static void print_literal(ClassLoaderWeakHandle l) {
coleenp@50313 260 l.print();
coleenp@50313 261 }
duke@1 262
zgu@13195 263 template <class T, MEMFLAGS F> void Hashtable<T, F>::print() {
duke@1 264 ResourceMark rm;
duke@1 265
zgu@13195 266 for (int i = 0; i < BasicHashtable<F>::table_size(); i++) {
zgu@13195 267 HashtableEntry<T, F>* entry = bucket(i);
duke@1 268 while(entry != NULL) {
duke@1 269 tty->print("%d : ", i);
coleenp@50313 270 print_literal(entry->literal());
duke@1 271 tty->cr();
duke@1 272 entry = entry->next();
duke@1 273 }
duke@1 274 }
duke@1 275 }
duke@1 276
coleenp@46475 277 template <MEMFLAGS F>
coleenp@46475 278 template <class T> void BasicHashtable<F>::verify_table(const char* table_name) {
coleenp@46475 279 int element_count = 0;
coleenp@46475 280 int max_bucket_count = 0;
coleenp@46545 281 int max_bucket_number = 0;
coleenp@46475 282 for (int index = 0; index < table_size(); index++) {
coleenp@46475 283 int bucket_count = 0;
coleenp@46475 284 for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
coleenp@46475 285 probe->verify();
coleenp@46475 286 bucket_count++;
duke@1 287 }
coleenp@46475 288 element_count += bucket_count;
coleenp@46545 289 if (bucket_count > max_bucket_count) {
coleenp@46545 290 max_bucket_count = bucket_count;
coleenp@46545 291 max_bucket_number = index;
coleenp@46545 292 }
duke@1 293 }
coleenp@46475 294 guarantee(number_of_entries() == element_count,
coleenp@46475 295 "Verify of %s failed", table_name);
coleenp@46545 296
coleenp@46545 297 // Log some statistics about the hashtable
coleenp@46545 298 log_info(hashtables)("%s max bucket size %d bucket %d element count %d table size %d", table_name,
coleenp@46545 299 max_bucket_count, max_bucket_number, _number_of_entries, _table_size);
coleenp@46545 300 if (_number_of_entries > 0 && log_is_enabled(Debug, hashtables)) {
coleenp@46545 301 for (int index = 0; index < table_size(); index++) {
coleenp@46545 302 int bucket_count = 0;
coleenp@46545 303 for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
coleenp@46545 304 log_debug(hashtables)("bucket %d hash " INTPTR_FORMAT, index, (intptr_t)probe->hash());
coleenp@46545 305 bucket_count++;
coleenp@46545 306 }
coleenp@46545 307 if (bucket_count > 0) {
coleenp@46545 308 log_debug(hashtables)("bucket %d count %d", index, bucket_count);
coleenp@46545 309 }
coleenp@46545 310 }
coleenp@46545 311 }
duke@1 312 }
duke@1 313 #endif // PRODUCT
duke@1 314
coleenp@8076 315 // Explicitly instantiate these types
mgerdin@26422 316 template class Hashtable<nmethod*, mtGC>;
mgerdin@26422 317 template class HashtableEntry<nmethod*, mtGC>;
mgerdin@26422 318 template class BasicHashtable<mtGC>;
coleenp@13728 319 template class Hashtable<ConstantPool*, mtClass>;
zgu@13195 320 template class Hashtable<Symbol*, mtSymbol>;
coleenp@13728 321 template class Hashtable<Klass*, mtClass>;
iklam@34257 322 template class Hashtable<InstanceKlass*, mtClass>;
coleenp@50313 323 template class Hashtable<ClassLoaderWeakHandle, mtClass>;
coleenp@46729 324 template class Hashtable<Symbol*, mtModule>;
zgu@13195 325 template class Hashtable<oop, mtSymbol>;
coleenp@50313 326 template class Hashtable<ClassLoaderWeakHandle, mtSymbol>;
zgu@13195 327 template class Hashtable<Symbol*, mtClass>;
zgu@13195 328 template class HashtableEntry<Symbol*, mtSymbol>;
zgu@13195 329 template class HashtableEntry<Symbol*, mtClass>;
zgu@13195 330 template class HashtableEntry<oop, mtSymbol>;
coleenp@50313 331 template class HashtableEntry<ClassLoaderWeakHandle, mtSymbol>;
iklam@46746 332 template class HashtableBucket<mtClass>;
zgu@13195 333 template class BasicHashtableEntry<mtSymbol>;
zgu@13195 334 template class BasicHashtableEntry<mtCode>;
zgu@13195 335 template class BasicHashtable<mtClass>;
iklam@34257 336 template class BasicHashtable<mtClassShared>;
zgu@13195 337 template class BasicHashtable<mtSymbol>;
zgu@13195 338 template class BasicHashtable<mtCode>;
zgu@13195 339 template class BasicHashtable<mtInternal>;
hseigel@38733 340 template class BasicHashtable<mtModule>;
kvn@30593 341 template class BasicHashtable<mtCompiler>;
coleenp@46475 342
coleenp@46475 343 template void BasicHashtable<mtClass>::verify_table<DictionaryEntry>(char const*);
coleenp@46475 344 template void BasicHashtable<mtModule>::verify_table<ModuleEntry>(char const*);
coleenp@46475 345 template void BasicHashtable<mtModule>::verify_table<PackageEntry>(char const*);
coleenp@46475 346 template void BasicHashtable<mtClass>::verify_table<ProtectionDomainCacheEntry>(char const*);
coleenp@46545 347 template void BasicHashtable<mtClass>::verify_table<PlaceholderEntry>(char const*);