annotate src/hotspot/share/utilities/hashtable.cpp @ 53599:3009ca99de32

8213587: Speed up CDS dump time by using resizable hashtables Reviewed-by: jiangli, coleenp, gziemski
author iklam
date Tue, 20 Nov 2018 20:00:15 -0800
parents f4e3900c8d08
children 61b3b58a1d1d
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);
iklam@53599 68 _entry_blocks->append(_first_free_entry);
duke@1 69 _end_block = _first_free_entry + len;
duke@1 70 }
zgu@13195 71 entry = (BasicHashtableEntry<F>*)_first_free_entry;
duke@1 72 _first_free_entry += _entry_size;
duke@1 73 }
duke@1 74
jrose@1551 75 assert(_entry_size % HeapWordSize == 0, "");
duke@1 76 entry->set_hash(hashValue);
duke@1 77 return entry;
duke@1 78 }
duke@1 79
duke@1 80
zgu@13195 81 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) {
zgu@13195 82 HashtableEntry<T, F>* entry;
duke@1 83
zgu@13195 84 entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue);
coleenp@8076 85 entry->set_literal(obj);
duke@1 86 return entry;
duke@1 87 }
duke@1 88
coleenp@46729 89 // Version of hashtable entry allocation that allocates in the C heap directly.
iklam@53599 90 // The block allocator in BasicHashtable has less fragmentation, but the memory is not freed until
iklam@53599 91 // the whole table is freed. Use allocate_new_entry() if you want to individually free the memory
iklam@53599 92 // used by each entry
coleenp@46729 93 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::allocate_new_entry(unsigned int hashValue, T obj) {
coleenp@46729 94 HashtableEntry<T, F>* entry = (HashtableEntry<T, F>*) NEW_C_HEAP_ARRAY(char, this->entry_size(), F);
coleenp@46729 95
coleenp@46729 96 entry->set_hash(hashValue);
coleenp@46729 97 entry->set_literal(obj);
coleenp@46729 98 entry->set_next(NULL);
coleenp@46729 99 return entry;
coleenp@46729 100 }
coleenp@46729 101
zgu@13195 102 template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() {
coleenp@13097 103 if (NULL != _buckets) {
iklam@53482 104 FREE_C_HEAP_ARRAY(HashtableBucket, _buckets);
coleenp@13097 105 _buckets = NULL;
coleenp@13097 106 }
coleenp@13097 107 }
coleenp@13097 108
tschatzl@45114 109 template <MEMFLAGS F> void BasicHashtable<F>::BucketUnlinkContext::free_entry(BasicHashtableEntry<F>* entry) {
tschatzl@45114 110 entry->set_next(_removed_head);
tschatzl@45114 111 _removed_head = entry;
tschatzl@45114 112 if (_removed_tail == NULL) {
tschatzl@45114 113 _removed_tail = entry;
tschatzl@45114 114 }
tschatzl@45114 115 _num_removed++;
tschatzl@45114 116 }
tschatzl@45114 117
tschatzl@45114 118 template <MEMFLAGS F> void BasicHashtable<F>::bulk_free_entries(BucketUnlinkContext* context) {
tschatzl@45114 119 if (context->_num_removed == 0) {
tschatzl@45114 120 assert(context->_removed_head == NULL && context->_removed_tail == NULL,
tschatzl@45114 121 "Zero entries in the unlink context, but elements linked from " PTR_FORMAT " to " PTR_FORMAT,
tschatzl@45114 122 p2i(context->_removed_head), p2i(context->_removed_tail));
tschatzl@45114 123 return;
tschatzl@45114 124 }
tschatzl@45114 125
tschatzl@45114 126 // MT-safe add of the list of BasicHashTableEntrys from the context to the free list.
tschatzl@45114 127 BasicHashtableEntry<F>* current = _free_list;
tschatzl@45114 128 while (true) {
tschatzl@45114 129 context->_removed_tail->set_next(current);
coleenp@47789 130 BasicHashtableEntry<F>* old = Atomic::cmpxchg(context->_removed_head, &_free_list, current);
tschatzl@45114 131 if (old == current) {
tschatzl@45114 132 break;
tschatzl@45114 133 }
tschatzl@45114 134 current = old;
tschatzl@45114 135 }
tschatzl@45114 136 Atomic::add(-context->_num_removed, &_number_of_entries);
tschatzl@45114 137 }
duke@1 138
coleenp@46742 139 // For oops and Strings the size of the literal is interesting. For other types, nobody cares.
coleenp@46742 140 static int literal_size(ConstantPool*) { return 0; }
coleenp@46742 141 static int literal_size(Klass*) { return 0; }
coleenp@46742 142 static int literal_size(nmethod*) { return 0; }
coleenp@46742 143
coleenp@46742 144 static int literal_size(Symbol *symbol) {
iklam@17610 145 return symbol->size() * HeapWordSize;
iklam@17610 146 }
iklam@17610 147
coleenp@46742 148 static int literal_size(oop obj) {
iklam@17610 149 // NOTE: this would over-count if (pre-JDK8) java_lang_Class::has_offset_field() is true,
iklam@17610 150 // and the String.value array is shared by several Strings. However, starting from JDK8,
iklam@17610 151 // the String.value array is not shared anymore.
coleenp@46742 152 if (obj == NULL) {
coleenp@46742 153 return 0;
coleenp@46742 154 } else if (obj->klass() == SystemDictionary::String_klass()) {
coleenp@46742 155 return (obj->size() + java_lang_String::value(obj)->size()) * HeapWordSize;
coleenp@46742 156 } else {
coleenp@46742 157 return obj->size();
coleenp@46742 158 }
iklam@17610 159 }
iklam@17610 160
coleenp@50313 161 static int literal_size(ClassLoaderWeakHandle v) {
coleenp@50313 162 return literal_size(v.peek());
coleenp@50313 163 }
coleenp@50313 164
gziemski@47955 165 template <MEMFLAGS F> bool BasicHashtable<F>::resize(int new_size) {
gziemski@47955 166 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
gziemski@47955 167
gziemski@47955 168 // Allocate new buckets
gziemski@47955 169 HashtableBucket<F>* buckets_new = NEW_C_HEAP_ARRAY2_RETURN_NULL(HashtableBucket<F>, new_size, F, CURRENT_PC);
gziemski@47955 170 if (buckets_new == NULL) {
gziemski@47955 171 return false;
gziemski@47955 172 }
gziemski@47955 173
gziemski@47955 174 // Clear the new buckets
gziemski@47955 175 for (int i = 0; i < new_size; i++) {
gziemski@47955 176 buckets_new[i].clear();
gziemski@47955 177 }
gziemski@47955 178
gziemski@47955 179 int table_size_old = _table_size;
gziemski@47955 180 // hash_to_index() uses _table_size, so switch the sizes now
gziemski@47955 181 _table_size = new_size;
gziemski@47955 182
gziemski@47955 183 // Move entries from the old table to a new table
gziemski@47955 184 for (int index_old = 0; index_old < table_size_old; index_old++) {
gziemski@47955 185 for (BasicHashtableEntry<F>* p = _buckets[index_old].get_entry(); p != NULL; ) {
gziemski@47955 186 BasicHashtableEntry<F>* next = p->next();
gziemski@47955 187 bool keep_shared = p->is_shared();
gziemski@47955 188 int index_new = hash_to_index(p->hash());
gziemski@47955 189
gziemski@47955 190 p->set_next(buckets_new[index_new].get_entry());
gziemski@47955 191 buckets_new[index_new].set_entry(p);
gziemski@47955 192
gziemski@47955 193 if (keep_shared) {
gziemski@47955 194 p->set_shared();
gziemski@47955 195 }
gziemski@47955 196 p = next;
gziemski@47955 197 }
gziemski@47955 198 }
gziemski@47955 199
gziemski@47955 200 // The old backets now can be released
gziemski@47955 201 BasicHashtable<F>::free_buckets();
gziemski@47955 202
gziemski@47955 203 // Switch to the new storage
gziemski@47955 204 _buckets = buckets_new;
gziemski@47955 205
gziemski@47955 206 return true;
gziemski@47955 207 }
coleenp@46742 208
iklam@53599 209 template <MEMFLAGS F> bool BasicHashtable<F>::maybe_grow(int max_size, int load_factor) {
iklam@53599 210 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
iklam@53599 211
iklam@53599 212 if (table_size() >= max_size) {
iklam@53599 213 return false;
iklam@53599 214 }
iklam@53599 215 if (number_of_entries() / table_size() > load_factor) {
iklam@53599 216 resize(MIN2<int>(table_size() * 2, max_size));
iklam@53599 217 return true;
iklam@53599 218 } else {
iklam@53599 219 return false;
iklam@53599 220 }
iklam@53599 221 }
iklam@53599 222
iklam@17610 223 // Dump footprint and bucket length statistics
iklam@17610 224 //
iklam@17610 225 // Note: if you create a new subclass of Hashtable<MyNewType, F>, you will need to
coleenp@46742 226 // add a new function static int literal_size(MyNewType lit)
coleenp@46742 227 // because I can't get template <class T> int literal_size(T) to pick the specializations for Symbol and oop.
coleenp@46742 228 //
coleenp@46742 229 // The StringTable and SymbolTable dumping print how much footprint is used by the String and Symbol
coleenp@46742 230 // literals.
iklam@17610 231
coleenp@46742 232 template <class T, MEMFLAGS F> void Hashtable<T, F>::print_table_statistics(outputStream* st,
stefank@50817 233 const char *table_name,
stefank@50817 234 T (*literal_load_barrier)(HashtableEntry<T, F>*)) {
iklam@17610 235 NumberSeq summary;
iklam@17610 236 int literal_bytes = 0;
iklam@17610 237 for (int i = 0; i < this->table_size(); ++i) {
iklam@17610 238 int count = 0;
mgerdin@26421 239 for (HashtableEntry<T, F>* e = this->bucket(i);
iklam@46746 240 e != NULL; e = e->next()) {
iklam@17610 241 count++;
stefank@50817 242 T l = (literal_load_barrier != NULL) ? literal_load_barrier(e) : e->literal();
stefank@50817 243 literal_bytes += literal_size(l);
iklam@17610 244 }
iklam@17610 245 summary.add((double)count);
iklam@17610 246 }
iklam@17610 247 double num_buckets = summary.num();
iklam@17610 248 double num_entries = summary.sum();
iklam@17610 249
mgerdin@26421 250 int bucket_bytes = (int)num_buckets * sizeof(HashtableBucket<F>);
iklam@17610 251 int entry_bytes = (int)num_entries * sizeof(HashtableEntry<T, F>);
iklam@17610 252 int total_bytes = literal_bytes + bucket_bytes + entry_bytes;
iklam@17610 253
coleenp@46742 254 int bucket_size = (num_buckets <= 0) ? 0 : (bucket_bytes / num_buckets);
coleenp@46742 255 int entry_size = (num_entries <= 0) ? 0 : (entry_bytes / num_entries);
iklam@17610 256
iklam@17610 257 st->print_cr("%s statistics:", table_name);
coleenp@46742 258 st->print_cr("Number of buckets : %9d = %9d bytes, each %d", (int)num_buckets, bucket_bytes, bucket_size);
coleenp@46742 259 st->print_cr("Number of entries : %9d = %9d bytes, each %d", (int)num_entries, entry_bytes, entry_size);
coleenp@46742 260 if (literal_bytes != 0) {
coleenp@46742 261 double literal_avg = (num_entries <= 0) ? 0 : (literal_bytes / num_entries);
coleenp@46742 262 st->print_cr("Number of literals : %9d = %9d bytes, avg %7.3f", (int)num_entries, literal_bytes, literal_avg);
coleenp@46742 263 }
iklam@17610 264 st->print_cr("Total footprint : %9s = %9d bytes", "", total_bytes);
iklam@17610 265 st->print_cr("Average bucket size : %9.3f", summary.avg());
iklam@17610 266 st->print_cr("Variance of bucket size : %9.3f", summary.variance());
iklam@17610 267 st->print_cr("Std. dev. of bucket size: %9.3f", summary.sd());
iklam@17610 268 st->print_cr("Maximum bucket size : %9d", (int)summary.maximum());
iklam@17610 269 }
iklam@17610 270
duke@1 271 #ifndef PRODUCT
coleenp@50313 272 template <class T> void print_literal(T l) {
coleenp@50313 273 l->print();
coleenp@50313 274 }
coleenp@50313 275
coleenp@50313 276 static void print_literal(ClassLoaderWeakHandle l) {
coleenp@50313 277 l.print();
coleenp@50313 278 }
duke@1 279
zgu@13195 280 template <class T, MEMFLAGS F> void Hashtable<T, F>::print() {
duke@1 281 ResourceMark rm;
duke@1 282
zgu@13195 283 for (int i = 0; i < BasicHashtable<F>::table_size(); i++) {
zgu@13195 284 HashtableEntry<T, F>* entry = bucket(i);
duke@1 285 while(entry != NULL) {
duke@1 286 tty->print("%d : ", i);
coleenp@50313 287 print_literal(entry->literal());
duke@1 288 tty->cr();
duke@1 289 entry = entry->next();
duke@1 290 }
duke@1 291 }
duke@1 292 }
duke@1 293
coleenp@46475 294 template <MEMFLAGS F>
coleenp@46475 295 template <class T> void BasicHashtable<F>::verify_table(const char* table_name) {
coleenp@46475 296 int element_count = 0;
coleenp@46475 297 int max_bucket_count = 0;
coleenp@46545 298 int max_bucket_number = 0;
coleenp@46475 299 for (int index = 0; index < table_size(); index++) {
coleenp@46475 300 int bucket_count = 0;
coleenp@46475 301 for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
coleenp@46475 302 probe->verify();
coleenp@46475 303 bucket_count++;
duke@1 304 }
coleenp@46475 305 element_count += bucket_count;
coleenp@46545 306 if (bucket_count > max_bucket_count) {
coleenp@46545 307 max_bucket_count = bucket_count;
coleenp@46545 308 max_bucket_number = index;
coleenp@46545 309 }
duke@1 310 }
coleenp@46475 311 guarantee(number_of_entries() == element_count,
coleenp@46475 312 "Verify of %s failed", table_name);
coleenp@46545 313
coleenp@46545 314 // Log some statistics about the hashtable
coleenp@46545 315 log_info(hashtables)("%s max bucket size %d bucket %d element count %d table size %d", table_name,
coleenp@46545 316 max_bucket_count, max_bucket_number, _number_of_entries, _table_size);
coleenp@46545 317 if (_number_of_entries > 0 && log_is_enabled(Debug, hashtables)) {
coleenp@46545 318 for (int index = 0; index < table_size(); index++) {
coleenp@46545 319 int bucket_count = 0;
coleenp@46545 320 for (T* probe = (T*)bucket(index); probe != NULL; probe = probe->next()) {
coleenp@46545 321 log_debug(hashtables)("bucket %d hash " INTPTR_FORMAT, index, (intptr_t)probe->hash());
coleenp@46545 322 bucket_count++;
coleenp@46545 323 }
coleenp@46545 324 if (bucket_count > 0) {
coleenp@46545 325 log_debug(hashtables)("bucket %d count %d", index, bucket_count);
coleenp@46545 326 }
coleenp@46545 327 }
coleenp@46545 328 }
duke@1 329 }
duke@1 330 #endif // PRODUCT
duke@1 331
coleenp@8076 332 // Explicitly instantiate these types
mgerdin@26422 333 template class Hashtable<nmethod*, mtGC>;
mgerdin@26422 334 template class HashtableEntry<nmethod*, mtGC>;
mgerdin@26422 335 template class BasicHashtable<mtGC>;
coleenp@13728 336 template class Hashtable<ConstantPool*, mtClass>;
zgu@13195 337 template class Hashtable<Symbol*, mtSymbol>;
coleenp@13728 338 template class Hashtable<Klass*, mtClass>;
iklam@34257 339 template class Hashtable<InstanceKlass*, mtClass>;
coleenp@50313 340 template class Hashtable<ClassLoaderWeakHandle, mtClass>;
coleenp@46729 341 template class Hashtable<Symbol*, mtModule>;
zgu@13195 342 template class Hashtable<oop, mtSymbol>;
coleenp@50313 343 template class Hashtable<ClassLoaderWeakHandle, mtSymbol>;
zgu@13195 344 template class Hashtable<Symbol*, mtClass>;
zgu@13195 345 template class HashtableEntry<Symbol*, mtSymbol>;
zgu@13195 346 template class HashtableEntry<Symbol*, mtClass>;
zgu@13195 347 template class HashtableEntry<oop, mtSymbol>;
coleenp@50313 348 template class HashtableEntry<ClassLoaderWeakHandle, mtSymbol>;
iklam@46746 349 template class HashtableBucket<mtClass>;
zgu@13195 350 template class BasicHashtableEntry<mtSymbol>;
zgu@13195 351 template class BasicHashtableEntry<mtCode>;
zgu@13195 352 template class BasicHashtable<mtClass>;
iklam@34257 353 template class BasicHashtable<mtClassShared>;
zgu@13195 354 template class BasicHashtable<mtSymbol>;
zgu@13195 355 template class BasicHashtable<mtCode>;
zgu@13195 356 template class BasicHashtable<mtInternal>;
hseigel@38733 357 template class BasicHashtable<mtModule>;
kvn@30593 358 template class BasicHashtable<mtCompiler>;
coleenp@46475 359
coleenp@46475 360 template void BasicHashtable<mtClass>::verify_table<DictionaryEntry>(char const*);
coleenp@46475 361 template void BasicHashtable<mtModule>::verify_table<ModuleEntry>(char const*);
coleenp@46475 362 template void BasicHashtable<mtModule>::verify_table<PackageEntry>(char const*);
coleenp@46475 363 template void BasicHashtable<mtClass>::verify_table<ProtectionDomainCacheEntry>(char const*);
coleenp@46545 364 template void BasicHashtable<mtClass>::verify_table<PlaceholderEntry>(char const*);