annotate hotspot/src/share/vm/utilities/hashtable.cpp @ 20282:7f9cbdf89af2

7195622: CheckUnhandledOops has limited usefulness now Summary: Enable CHECK_UNHANDLED_OOPS in fastdebug builds across all supported platforms. Reviewed-by: coleenp, hseigel, dholmes, stefank, twisti, ihse, rdurbin Contributed-by: lois.foltan@oracle.com
author hseigel
date Thu, 26 Sep 2013 10:25:02 -0400
parents c6857feaac47
children b2cbb3680b4f
rev   line source
duke@1 1 /*
hseigel@20282 2 * Copyright (c) 2003, 2013, 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@13199 27 #include "classfile/javaClasses.hpp"
stefank@7397 28 #include "memory/allocation.inline.hpp"
coleenp@13097 29 #include "memory/filemap.hpp"
stefank@7397 30 #include "memory/resourceArea.hpp"
stefank@7397 31 #include "oops/oop.inline.hpp"
stefank@7397 32 #include "runtime/safepoint.hpp"
stefank@7397 33 #include "utilities/dtrace.hpp"
stefank@7397 34 #include "utilities/hashtable.hpp"
stefank@7397 35 #include "utilities/hashtable.inline.hpp"
iklam@17610 36 #include "utilities/numberSeq.hpp"
duke@1 37
coleenp@8076 38
duke@1 39 // This is a generic hashtable, designed to be used for the symbol
duke@1 40 // and string tables.
duke@1 41 //
duke@1 42 // It is implemented as an open hash table with a fixed number of buckets.
duke@1 43 //
duke@1 44 // %note:
duke@1 45 // - HashtableEntrys are allocated in blocks to reduce the space overhead.
duke@1 46
zgu@13195 47 template <MEMFLAGS F> BasicHashtableEntry<F>* BasicHashtable<F>::new_entry(unsigned int hashValue) {
zgu@13195 48 BasicHashtableEntry<F>* entry;
duke@1 49
duke@1 50 if (_free_list) {
duke@1 51 entry = _free_list;
duke@1 52 _free_list = _free_list->next();
duke@1 53 } else {
jrose@1551 54 if (_first_free_entry + _entry_size >= _end_block) {
jrose@1551 55 int block_size = MIN2(512, MAX2((int)_table_size / 2, (int)_number_of_entries));
duke@1 56 int len = _entry_size * block_size;
jrose@1551 57 len = 1 << log2_intptr(len); // round down to power of 2
jrose@1551 58 assert(len >= _entry_size, "");
zgu@13195 59 _first_free_entry = NEW_C_HEAP_ARRAY2(char, len, F, CURRENT_PC);
duke@1 60 _end_block = _first_free_entry + len;
duke@1 61 }
zgu@13195 62 entry = (BasicHashtableEntry<F>*)_first_free_entry;
duke@1 63 _first_free_entry += _entry_size;
duke@1 64 }
duke@1 65
jrose@1551 66 assert(_entry_size % HeapWordSize == 0, "");
duke@1 67 entry->set_hash(hashValue);
duke@1 68 return entry;
duke@1 69 }
duke@1 70
duke@1 71
zgu@13195 72 template <class T, MEMFLAGS F> HashtableEntry<T, F>* Hashtable<T, F>::new_entry(unsigned int hashValue, T obj) {
zgu@13195 73 HashtableEntry<T, F>* entry;
duke@1 74
zgu@13195 75 entry = (HashtableEntry<T, F>*)BasicHashtable<F>::new_entry(hashValue);
coleenp@8076 76 entry->set_literal(obj);
duke@1 77 return entry;
duke@1 78 }
duke@1 79
coleenp@13087 80 // Check to see if the hashtable is unbalanced. The caller set a flag to
coleenp@13087 81 // rehash at the next safepoint. If this bucket is 60 times greater than the
coleenp@13087 82 // expected average bucket length, it's an unbalanced hashtable.
coleenp@13087 83 // This is somewhat an arbitrary heuristic but if one bucket gets to
coleenp@13087 84 // rehash_count which is currently 100, there's probably something wrong.
coleenp@13087 85
zgu@13195 86 template <MEMFLAGS F> bool BasicHashtable<F>::check_rehash_table(int count) {
coleenp@13087 87 assert(table_size() != 0, "underflow");
coleenp@13087 88 if (count > (((double)number_of_entries()/(double)table_size())*rehash_multiple)) {
coleenp@13087 89 // Set a flag for the next safepoint, which should be at some guaranteed
coleenp@13087 90 // safepoint interval.
coleenp@13087 91 return true;
coleenp@13087 92 }
coleenp@13087 93 return false;
coleenp@13087 94 }
coleenp@13087 95
coleenp@13199 96 template <class T, MEMFLAGS F> jint Hashtable<T, F>::_seed = 0;
coleenp@13199 97
coleenp@13087 98 // Create a new table and using alternate hash code, populate the new table
coleenp@13087 99 // with the existing elements. This can be used to change the hash code
coleenp@13087 100 // and could in the future change the size of the table.
coleenp@13087 101
zgu@13195 102 template <class T, MEMFLAGS F> void Hashtable<T, F>::move_to(Hashtable<T, F>* new_table) {
coleenp@13199 103
coleenp@13199 104 // Initialize the global seed for hashing.
coleenp@13199 105 _seed = AltHashing::compute_seed();
coleenp@13199 106 assert(seed() != 0, "shouldn't be zero");
coleenp@13199 107
coleenp@13199 108 int saved_entry_count = this->number_of_entries();
coleenp@13087 109
coleenp@13087 110 // Iterate through the table and create a new entry for the new table
coleenp@13087 111 for (int i = 0; i < new_table->table_size(); ++i) {
zgu@13195 112 for (HashtableEntry<T, F>* p = bucket(i); p != NULL; ) {
zgu@13195 113 HashtableEntry<T, F>* next = p->next();
coleenp@13087 114 T string = p->literal();
coleenp@13087 115 // Use alternate hashing algorithm on the symbol in the first table
coleenp@13728 116 unsigned int hashValue = string->new_hash(seed());
coleenp@13087 117 // Get a new index relative to the new table (can also change size)
coleenp@13087 118 int index = new_table->hash_to_index(hashValue);
coleenp@13087 119 p->set_hash(hashValue);
coleenp@13097 120 // Keep the shared bit in the Hashtable entry to indicate that this entry
coleenp@13097 121 // can't be deleted. The shared bit is the LSB in the _next field so
coleenp@13097 122 // walking the hashtable past these entries requires
coleenp@13097 123 // BasicHashtableEntry::make_ptr() call.
coleenp@13097 124 bool keep_shared = p->is_shared();
andrew@13342 125 this->unlink_entry(p);
coleenp@13087 126 new_table->add_entry(index, p);
coleenp@13097 127 if (keep_shared) {
coleenp@13097 128 p->set_shared();
coleenp@13097 129 }
coleenp@13087 130 p = next;
coleenp@13087 131 }
coleenp@13087 132 }
coleenp@13087 133 // give the new table the free list as well
coleenp@13087 134 new_table->copy_freelist(this);
coleenp@13087 135 assert(new_table->number_of_entries() == saved_entry_count, "lost entry on dictionary copy?");
coleenp@13087 136
coleenp@13087 137 // Destroy memory used by the buckets in the hashtable. The memory
coleenp@13087 138 // for the elements has been used in a new table and is not
coleenp@13087 139 // destroyed. The memory reuse will benefit resizing the SystemDictionary
coleenp@13087 140 // to avoid a memory allocation spike at safepoint.
zgu@13195 141 BasicHashtable<F>::free_buckets();
coleenp@13087 142 }
coleenp@13087 143
zgu@13195 144 template <MEMFLAGS F> void BasicHashtable<F>::free_buckets() {
coleenp@13097 145 if (NULL != _buckets) {
coleenp@13097 146 // Don't delete the buckets in the shared space. They aren't
coleenp@13097 147 // allocated by os::malloc
coleenp@13097 148 if (!UseSharedSpaces ||
coleenp@13097 149 !FileMapInfo::current_info()->is_in_shared_space(_buckets)) {
zgu@13195 150 FREE_C_HEAP_ARRAY(HashtableBucket, _buckets, F);
coleenp@13097 151 }
coleenp@13097 152 _buckets = NULL;
coleenp@13097 153 }
coleenp@13097 154 }
coleenp@13097 155
coleenp@13097 156
duke@1 157 // Reverse the order of elements in the hash buckets.
duke@1 158
zgu@13195 159 template <MEMFLAGS F> void BasicHashtable<F>::reverse() {
duke@1 160
duke@1 161 for (int i = 0; i < _table_size; ++i) {
zgu@13195 162 BasicHashtableEntry<F>* new_list = NULL;
zgu@13195 163 BasicHashtableEntry<F>* p = bucket(i);
duke@1 164 while (p != NULL) {
zgu@13195 165 BasicHashtableEntry<F>* next = p->next();
duke@1 166 p->set_next(new_list);
duke@1 167 new_list = p;
duke@1 168 p = next;
duke@1 169 }
duke@1 170 *bucket_addr(i) = new_list;
duke@1 171 }
duke@1 172 }
duke@1 173
duke@1 174
duke@1 175 // Copy the table to the shared space.
duke@1 176
zgu@13195 177 template <MEMFLAGS F> void BasicHashtable<F>::copy_table(char** top, char* end) {
duke@1 178
duke@1 179 // Dump the hash table entries.
duke@1 180
duke@1 181 intptr_t *plen = (intptr_t*)(*top);
duke@1 182 *top += sizeof(*plen);
duke@1 183
duke@1 184 int i;
duke@1 185 for (i = 0; i < _table_size; ++i) {
zgu@13195 186 for (BasicHashtableEntry<F>** p = _buckets[i].entry_addr();
duke@1 187 *p != NULL;
duke@1 188 p = (*p)->next_addr()) {
duke@1 189 if (*top + entry_size() > end) {
coleenp@8076 190 report_out_of_shared_space(SharedMiscData);
duke@1 191 }
zgu@13195 192 *p = (BasicHashtableEntry<F>*)memcpy(*top, *p, entry_size());
duke@1 193 *top += entry_size();
duke@1 194 }
duke@1 195 }
duke@1 196 *plen = (char*)(*top) - (char*)plen - sizeof(*plen);
duke@1 197
duke@1 198 // Set the shared bit.
duke@1 199
duke@1 200 for (i = 0; i < _table_size; ++i) {
zgu@13195 201 for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
duke@1 202 p->set_shared();
duke@1 203 }
duke@1 204 }
duke@1 205 }
duke@1 206
duke@1 207
duke@1 208
duke@1 209 // Reverse the order of elements in the hash buckets.
duke@1 210
zgu@13195 211 template <class T, MEMFLAGS F> void Hashtable<T, F>::reverse(void* boundary) {
duke@1 212
zgu@13195 213 for (int i = 0; i < this->table_size(); ++i) {
zgu@13195 214 HashtableEntry<T, F>* high_list = NULL;
zgu@13195 215 HashtableEntry<T, F>* low_list = NULL;
zgu@13195 216 HashtableEntry<T, F>* last_low_entry = NULL;
zgu@13195 217 HashtableEntry<T, F>* p = bucket(i);
duke@1 218 while (p != NULL) {
zgu@13195 219 HashtableEntry<T, F>* next = p->next();
duke@1 220 if ((void*)p->literal() >= boundary) {
duke@1 221 p->set_next(high_list);
duke@1 222 high_list = p;
duke@1 223 } else {
duke@1 224 p->set_next(low_list);
duke@1 225 low_list = p;
duke@1 226 if (last_low_entry == NULL) {
duke@1 227 last_low_entry = p;
duke@1 228 }
duke@1 229 }
duke@1 230 p = next;
duke@1 231 }
duke@1 232 if (low_list != NULL) {
duke@1 233 *bucket_addr(i) = low_list;
duke@1 234 last_low_entry->set_next(high_list);
duke@1 235 } else {
duke@1 236 *bucket_addr(i) = high_list;
duke@1 237 }
duke@1 238 }
duke@1 239 }
duke@1 240
iklam@17610 241 template <class T, MEMFLAGS F> int Hashtable<T, F>::literal_size(Symbol *symbol) {
iklam@17610 242 return symbol->size() * HeapWordSize;
iklam@17610 243 }
iklam@17610 244
iklam@17610 245 template <class T, MEMFLAGS F> int Hashtable<T, F>::literal_size(oop oop) {
iklam@17610 246 // NOTE: this would over-count if (pre-JDK8) java_lang_Class::has_offset_field() is true,
iklam@17610 247 // and the String.value array is shared by several Strings. However, starting from JDK8,
iklam@17610 248 // the String.value array is not shared anymore.
iklam@17610 249 assert(oop != NULL && oop->klass() == SystemDictionary::String_klass(), "only strings are supported");
iklam@17610 250 return (oop->size() + java_lang_String::value(oop)->size()) * HeapWordSize;
iklam@17610 251 }
iklam@17610 252
iklam@17610 253 // Dump footprint and bucket length statistics
iklam@17610 254 //
iklam@17610 255 // Note: if you create a new subclass of Hashtable<MyNewType, F>, you will need to
iklam@17610 256 // add a new function Hashtable<T, F>::literal_size(MyNewType lit)
iklam@17610 257
iklam@17610 258 template <class T, MEMFLAGS F> void Hashtable<T, F>::dump_table(outputStream* st, const char *table_name) {
iklam@17610 259 NumberSeq summary;
iklam@17610 260 int literal_bytes = 0;
iklam@17610 261 for (int i = 0; i < this->table_size(); ++i) {
iklam@17610 262 int count = 0;
iklam@17610 263 for (HashtableEntry<T, F>* e = bucket(i);
iklam@17610 264 e != NULL; e = e->next()) {
iklam@17610 265 count++;
iklam@17610 266 literal_bytes += literal_size(e->literal());
iklam@17610 267 }
iklam@17610 268 summary.add((double)count);
iklam@17610 269 }
iklam@17610 270 double num_buckets = summary.num();
iklam@17610 271 double num_entries = summary.sum();
iklam@17610 272
iklam@17610 273 int bucket_bytes = (int)num_buckets * sizeof(bucket(0));
iklam@17610 274 int entry_bytes = (int)num_entries * sizeof(HashtableEntry<T, F>);
iklam@17610 275 int total_bytes = literal_bytes + bucket_bytes + entry_bytes;
iklam@17610 276
iklam@17610 277 double bucket_avg = (num_buckets <= 0) ? 0 : (bucket_bytes / num_buckets);
iklam@17610 278 double entry_avg = (num_entries <= 0) ? 0 : (entry_bytes / num_entries);
iklam@17610 279 double literal_avg = (num_entries <= 0) ? 0 : (literal_bytes / num_entries);
iklam@17610 280
iklam@17610 281 st->print_cr("%s statistics:", table_name);
iklam@17610 282 st->print_cr("Number of buckets : %9d = %9d bytes, avg %7.3f", (int)num_buckets, bucket_bytes, bucket_avg);
iklam@17610 283 st->print_cr("Number of entries : %9d = %9d bytes, avg %7.3f", (int)num_entries, entry_bytes, entry_avg);
iklam@17610 284 st->print_cr("Number of literals : %9d = %9d bytes, avg %7.3f", (int)num_entries, literal_bytes, literal_avg);
iklam@17610 285 st->print_cr("Total footprint : %9s = %9d bytes", "", total_bytes);
iklam@17610 286 st->print_cr("Average bucket size : %9.3f", summary.avg());
iklam@17610 287 st->print_cr("Variance of bucket size : %9.3f", summary.variance());
iklam@17610 288 st->print_cr("Std. dev. of bucket size: %9.3f", summary.sd());
iklam@17610 289 st->print_cr("Maximum bucket size : %9d", (int)summary.maximum());
iklam@17610 290 }
iklam@17610 291
duke@1 292
duke@1 293 // Dump the hash table buckets.
duke@1 294
zgu@13195 295 template <MEMFLAGS F> void BasicHashtable<F>::copy_buckets(char** top, char* end) {
zgu@13195 296 intptr_t len = _table_size * sizeof(HashtableBucket<F>);
duke@1 297 *(intptr_t*)(*top) = len;
duke@1 298 *top += sizeof(intptr_t);
duke@1 299
duke@1 300 *(intptr_t*)(*top) = _number_of_entries;
duke@1 301 *top += sizeof(intptr_t);
duke@1 302
duke@1 303 if (*top + len > end) {
coleenp@8076 304 report_out_of_shared_space(SharedMiscData);
duke@1 305 }
zgu@13195 306 _buckets = (HashtableBucket<F>*)memcpy(*top, _buckets, len);
duke@1 307 *top += len;
duke@1 308 }
duke@1 309
duke@1 310
duke@1 311 #ifndef PRODUCT
duke@1 312
zgu@13195 313 template <class T, MEMFLAGS F> void Hashtable<T, F>::print() {
duke@1 314 ResourceMark rm;
duke@1 315
zgu@13195 316 for (int i = 0; i < BasicHashtable<F>::table_size(); i++) {
zgu@13195 317 HashtableEntry<T, F>* entry = bucket(i);
duke@1 318 while(entry != NULL) {
duke@1 319 tty->print("%d : ", i);
duke@1 320 entry->literal()->print();
duke@1 321 tty->cr();
duke@1 322 entry = entry->next();
duke@1 323 }
duke@1 324 }
duke@1 325 }
duke@1 326
duke@1 327
zgu@13195 328 template <MEMFLAGS F> void BasicHashtable<F>::verify() {
duke@1 329 int count = 0;
duke@1 330 for (int i = 0; i < table_size(); i++) {
zgu@13195 331 for (BasicHashtableEntry<F>* p = bucket(i); p != NULL; p = p->next()) {
duke@1 332 ++count;
duke@1 333 }
duke@1 334 }
duke@1 335 assert(count == number_of_entries(), "number of hashtable entries incorrect");
duke@1 336 }
duke@1 337
duke@1 338
duke@1 339 #endif // PRODUCT
duke@1 340
duke@1 341
duke@1 342 #ifdef ASSERT
duke@1 343
zgu@13195 344 template <MEMFLAGS F> void BasicHashtable<F>::verify_lookup_length(double load) {
duke@1 345 if ((double)_lookup_length / (double)_lookup_count > load * 2.0) {
duke@1 346 warning("Performance bug: SystemDictionary lookup_count=%d "
duke@1 347 "lookup_length=%d average=%lf load=%f",
duke@1 348 _lookup_count, _lookup_length,
duke@1 349 (double) _lookup_length / _lookup_count, load);
duke@1 350 }
duke@1 351 }
duke@1 352
duke@1 353 #endif
coleenp@8076 354 // Explicitly instantiate these types
coleenp@13728 355 template class Hashtable<ConstantPool*, mtClass>;
zgu@13195 356 template class Hashtable<Symbol*, mtSymbol>;
coleenp@13728 357 template class Hashtable<Klass*, mtClass>;
zgu@13195 358 template class Hashtable<oop, mtClass>;
hseigel@20282 359 #if defined(SOLARIS) || defined(CHECK_UNHANDLED_OOPS)
zgu@13195 360 template class Hashtable<oop, mtSymbol>;
hseigel@20282 361 #endif // SOLARIS || CHECK_UNHANDLED_OOPS
zgu@13195 362 template class Hashtable<oopDesc*, mtSymbol>;
zgu@13195 363 template class Hashtable<Symbol*, mtClass>;
zgu@13195 364 template class HashtableEntry<Symbol*, mtSymbol>;
zgu@13195 365 template class HashtableEntry<Symbol*, mtClass>;
zgu@13195 366 template class HashtableEntry<oop, mtSymbol>;
zgu@13195 367 template class BasicHashtableEntry<mtSymbol>;
zgu@13195 368 template class BasicHashtableEntry<mtCode>;
zgu@13195 369 template class BasicHashtable<mtClass>;
zgu@13195 370 template class BasicHashtable<mtSymbol>;
zgu@13195 371 template class BasicHashtable<mtCode>;
zgu@13195 372 template class BasicHashtable<mtInternal>;