1 /* 2 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "classfile/dictionary.hpp" 27 #include "classfile/loaderConstraints.hpp" 28 #include "classfile/placeholders.hpp" 29 #include "classfile/symbolTable.hpp" 30 #include "classfile/systemDictionary.hpp" 31 #include "code/codeCache.hpp" 32 #include "memory/filemap.hpp" 33 #include "memory/gcLocker.hpp" 34 #include "memory/metaspace.hpp" 35 #include "memory/metaspaceShared.hpp" 36 #include "oops/objArrayOop.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "runtime/signature.hpp" 39 #include "runtime/vm_operations.hpp" 40 #include "runtime/vmThread.hpp" 41 #include "utilities/hashtable.inline.hpp" 42 43 44 int MetaspaceShared::_max_alignment = 0; 45 46 ReservedSpace* MetaspaceShared::_shared_rs = NULL; 47 48 // Read/write a data stream for restoring/preserving metadata pointers and 49 // miscellaneous data from/to the shared archive file. 50 51 void MetaspaceShared::serialize(SerializeClosure* soc) { 52 int tag = 0; 53 soc->do_tag(--tag); 54 55 // Verify the sizes of various metadata in the system. 56 soc->do_tag(sizeof(Method)); 57 soc->do_tag(sizeof(ConstMethod)); 58 soc->do_tag(arrayOopDesc::base_offset_in_bytes(T_BYTE)); 59 soc->do_tag(sizeof(ConstantPool)); 60 soc->do_tag(sizeof(ConstantPoolCache)); 61 soc->do_tag(objArrayOopDesc::base_offset_in_bytes()); 62 soc->do_tag(typeArrayOopDesc::base_offset_in_bytes(T_BYTE)); 63 soc->do_tag(sizeof(Symbol)); 64 65 // Dump/restore miscellaneous metadata. 66 Universe::serialize(soc, true); 67 soc->do_tag(--tag); 68 69 // Dump/restore references to commonly used names and signatures. 70 vmSymbols::serialize(soc); 71 soc->do_tag(--tag); 72 73 soc->do_tag(666); 74 } 75 76 77 // CDS code for dumping shared archive. 78 79 // Global object for holding classes that have been loaded. Since this 80 // is run at a safepoint just before exit, this is the entire set of classes. 81 static GrowableArray<Klass*>* _global_klass_objects; 82 static void collect_classes(Klass* k) { 83 _global_klass_objects->append_if_missing(k); 84 if (k->oop_is_instance()) { 85 // Add in the array classes too 86 InstanceKlass* ik = InstanceKlass::cast(k); 87 ik->array_klasses_do(collect_classes); 88 } 89 } 90 91 static void remove_unshareable_in_classes() { 92 for (int i = 0; i < _global_klass_objects->length(); i++) { 93 Klass* k = _global_klass_objects->at(i); 94 k->remove_unshareable_info(); 95 } 96 } 97 98 // Walk all methods in the class list and assign a fingerprint. 99 // so that this part of the ConstMethod* is read only. 100 static void calculate_fingerprints() { 101 for (int i = 0; i < _global_klass_objects->length(); i++) { 102 Klass* k = _global_klass_objects->at(i); 103 if (k->oop_is_instance()) { 104 InstanceKlass* ik = InstanceKlass::cast(k); 105 for (int i = 0; i < ik->methods()->length(); i++) { 106 Method* m = ik->methods()->at(i); 107 Fingerprinter fp(m); 108 // The side effect of this call sets method's fingerprint field. 109 fp.fingerprint(); 110 } 111 } 112 } 113 } 114 115 // Patch C++ vtable pointer in metadata. 116 117 // Klass and other metadata objects contain references to c++ vtables in the 118 // JVM library. 119 // Fix them to point to our constructed vtables. However, don't iterate 120 // across the space while doing this, as that causes the vtables to be 121 // patched, undoing our useful work. Instead, iterate to make a list, 122 // then use the list to do the fixing. 123 // 124 // Our constructed vtables: 125 // Dump time: 126 // 1. init_self_patching_vtbl_list: table of pointers to current virtual method addrs 127 // 2. generate_vtable_methods: create jump table, appended to above vtbl_list 128 // 3. patch_klass_vtables: for Klass list, patch the vtable entry in klass and 129 // associated metadata to point to jump table rather than to current vtbl 130 // Table layout: NOTE FIXED SIZE 131 // 1. vtbl pointers 132 // 2. #Klass X #virtual methods per Klass 133 // 1 entry for each, in the order: 134 // Klass1:method1 entry, Klass1:method2 entry, ... Klass1:method<num_virtuals> entry 135 // Klass2:method1 entry, Klass2:method2 entry, ... Klass2:method<num_virtuals> entry 136 // ... 137 // Klass<vtbl_list_size>:method1 entry, Klass<vtbl_list_size>:method2 entry, 138 // ... Klass<vtbl_list_size>:method<num_virtuals> entry 139 // Sample entry: (Sparc): 140 // save(sp, -256, sp) 141 // ba,pt common_code 142 // mov XXX, %L0 %L0 gets: Klass index <<8 + method index (note: max method index 255) 143 // 144 // Restore time: 145 // 1. initialize_shared_space: reserve space for table 146 // 2. init_self_patching_vtbl_list: update pointers to NEW virtual method addrs in text 147 // 148 // Execution time: 149 // First virtual method call for any object of these metadata types: 150 // 1. object->klass 151 // 2. vtable entry for that klass points to the jump table entries 152 // 3. branches to common_code with %O0/klass, %L0: Klass index <<8 + method index 153 // 4. common_code: 154 // Get address of new vtbl pointer for this Klass from updated table 155 // Update new vtbl pointer in the Klass: future virtual calls go direct 156 // Jump to method, using new vtbl pointer and method index 157 158 159 static void* find_matching_vtbl_ptr(void** vtbl_list, void* new_vtable_start, void* obj) { 160 void* old_vtbl_ptr = *(void**)obj; 161 for (int i = 0; i < MetaspaceShared::vtbl_list_size; i++) { 162 if (vtbl_list[i] == old_vtbl_ptr) { 163 return (void**)new_vtable_start + i * MetaspaceShared::num_virtuals; 164 } 165 } 166 ShouldNotReachHere(); 167 return NULL; 168 } 169 170 // Assumes the vtable is in first slot in object. 171 static void patch_klass_vtables(void** vtbl_list, void* new_vtable_start) { 172 int n = _global_klass_objects->length(); 173 for (int i = 0; i < n; i++) { 174 Klass* obj = _global_klass_objects->at(i); 175 // Note oop_is_instance() is a virtual call. After patching vtables 176 // all virtual calls on the dummy vtables will restore the original! 177 if (obj->oop_is_instance()) { 178 InstanceKlass* ik = InstanceKlass::cast(obj); 179 *(void**)ik = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, ik); 180 ConstantPool* cp = ik->constants(); 181 *(void**)cp = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, cp); 182 for (int j = 0; j < ik->methods()->length(); j++) { 183 Method* m = ik->methods()->at(j); 184 *(void**)m = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, m); 185 } 186 } else { 187 // Array klasses 188 Klass* k = obj; 189 *(void**)k = find_matching_vtbl_ptr(vtbl_list, new_vtable_start, k); 190 } 191 } 192 } 193 194 // Closure for serializing initialization data out to a data area to be 195 // written to the shared file. 196 197 class WriteClosure : public SerializeClosure { 198 private: 199 intptr_t* top; 200 char* end; 201 202 inline void check_space() { 203 if ((char*)top + sizeof(intptr_t) > end) { 204 report_out_of_shared_space(SharedMiscData); 205 } 206 } 207 208 public: 209 WriteClosure(char* md_top, char* md_end) { 210 top = (intptr_t*)md_top; 211 end = md_end; 212 } 213 214 char* get_top() { return (char*)top; } 215 216 void do_ptr(void** p) { 217 check_space(); 218 *top = (intptr_t)*p; 219 ++top; 220 } 221 222 void do_tag(int tag) { 223 check_space(); 224 *top = (intptr_t)tag; 225 ++top; 226 } 227 228 void do_region(u_char* start, size_t size) { 229 if ((char*)top + size > end) { 230 report_out_of_shared_space(SharedMiscData); 231 } 232 assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); 233 assert(size % sizeof(intptr_t) == 0, "bad size"); 234 do_tag((int)size); 235 while (size > 0) { 236 *top = *(intptr_t*)start; 237 ++top; 238 start += sizeof(intptr_t); 239 size -= sizeof(intptr_t); 240 } 241 } 242 243 bool reading() const { return false; } 244 }; 245 246 // This is for dumping detailed statistics for the allocations 247 // in the shared spaces. 248 class DumpAllocClosure : public Metaspace::AllocRecordClosure { 249 public: 250 251 // Here's poor man's enum inheritance 252 #define SHAREDSPACE_OBJ_TYPES_DO(f) \ 253 METASPACE_OBJ_TYPES_DO(f) \ 254 f(SymbolHashentry) \ 255 f(SymbolBuckets) \ 256 f(Other) 257 258 #define SHAREDSPACE_OBJ_TYPE_DECLARE(name) name ## Type, 259 #define SHAREDSPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name; 260 261 enum Type { 262 // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc 263 SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_DECLARE) 264 _number_of_types 265 }; 266 267 static const char * type_name(Type type) { 268 switch(type) { 269 SHAREDSPACE_OBJ_TYPES_DO(SHAREDSPACE_OBJ_TYPE_NAME_CASE) 270 default: 271 ShouldNotReachHere(); 272 return NULL; 273 } 274 } 275 276 public: 277 enum { 278 RO = 0, 279 RW = 1 280 }; 281 282 int _counts[2][_number_of_types]; 283 int _bytes [2][_number_of_types]; 284 int _which; 285 286 DumpAllocClosure() { 287 memset(_counts, 0, sizeof(_counts)); 288 memset(_bytes, 0, sizeof(_bytes)); 289 }; 290 291 void iterate_metaspace(Metaspace* space, int which) { 292 assert(which == RO || which == RW, "sanity"); 293 _which = which; 294 space->iterate(this); 295 } 296 297 virtual void doit(address ptr, MetaspaceObj::Type type, int byte_size) { 298 assert(int(type) >= 0 && type < MetaspaceObj::_number_of_types, "sanity"); 299 _counts[_which][type] ++; 300 _bytes [_which][type] += byte_size; 301 } 302 303 void dump_stats(int ro_all, int rw_all, int md_all, int mc_all); 304 }; 305 306 void DumpAllocClosure::dump_stats(int ro_all, int rw_all, int md_all, int mc_all) { 307 rw_all += (md_all + mc_all); // md and mc are all mapped Read/Write 308 int other_bytes = md_all + mc_all; 309 310 // Calculate size of data that was not allocated by Metaspace::allocate() 311 int symbol_count = _counts[RO][MetaspaceObj::SymbolType]; 312 int symhash_bytes = symbol_count * sizeof (HashtableEntry<Symbol*, mtSymbol>); 313 int symbuck_count = SymbolTable::the_table()->table_size(); 314 int symbuck_bytes = symbuck_count * sizeof(HashtableBucket<mtSymbol>); 315 316 _counts[RW][SymbolHashentryType] = symbol_count; 317 _bytes [RW][SymbolHashentryType] = symhash_bytes; 318 other_bytes -= symhash_bytes; 319 320 _counts[RW][SymbolBucketsType] = symbuck_count; 321 _bytes [RW][SymbolBucketsType] = symbuck_bytes; 322 other_bytes -= symbuck_bytes; 323 324 // TODO: count things like dictionary, vtable, etc 325 _bytes[RW][OtherType] = other_bytes; 326 327 // prevent divide-by-zero 328 if (ro_all < 1) { 329 ro_all = 1; 330 } 331 if (rw_all < 1) { 332 rw_all = 1; 333 } 334 335 int all_ro_count = 0; 336 int all_ro_bytes = 0; 337 int all_rw_count = 0; 338 int all_rw_bytes = 0; 339 340 const char *fmt = "%-20s: %8d %10d %5.1f | %8d %10d %5.1f | %8d %10d %5.1f"; 341 const char *sep = "--------------------+---------------------------+---------------------------+--------------------------"; 342 const char *hdr = " ro_cnt ro_bytes % | rw_cnt rw_bytes % | all_cnt all_bytes %"; 343 344 tty->print_cr("Detailed metadata info (rw includes md and mc):"); 345 tty->print_cr(hdr); 346 tty->print_cr(sep); 347 for (int type = 0; type < int(_number_of_types); type ++) { 348 const char *name = type_name((Type)type); 349 int ro_count = _counts[RO][type]; 350 int ro_bytes = _bytes [RO][type]; 351 int rw_count = _counts[RW][type]; 352 int rw_bytes = _bytes [RW][type]; 353 int count = ro_count + rw_count; 354 int bytes = ro_bytes + rw_bytes; 355 356 double ro_perc = 100.0 * double(ro_bytes) / double(ro_all); 357 double rw_perc = 100.0 * double(rw_bytes) / double(rw_all); 358 double perc = 100.0 * double(bytes) / double(ro_all + rw_all); 359 360 tty->print_cr(fmt, name, 361 ro_count, ro_bytes, ro_perc, 362 rw_count, rw_bytes, rw_perc, 363 count, bytes, perc); 364 365 all_ro_count += ro_count; 366 all_ro_bytes += ro_bytes; 367 all_rw_count += rw_count; 368 all_rw_bytes += rw_bytes; 369 } 370 371 int all_count = all_ro_count + all_rw_count; 372 int all_bytes = all_ro_bytes + all_rw_bytes; 373 374 double all_ro_perc = 100.0 * double(all_ro_bytes) / double(ro_all); 375 double all_rw_perc = 100.0 * double(all_rw_bytes) / double(rw_all); 376 double all_perc = 100.0 * double(all_bytes) / double(ro_all + rw_all); 377 378 tty->print_cr(sep); 379 tty->print_cr(fmt, "Total", 380 all_ro_count, all_ro_bytes, all_ro_perc, 381 all_rw_count, all_rw_bytes, all_rw_perc, 382 all_count, all_bytes, all_perc); 383 384 assert(all_ro_bytes == ro_all, "everything should have been counted"); 385 assert(all_rw_bytes == rw_all, "everything should have been counted"); 386 } 387 388 // Populate the shared space. 389 390 class VM_PopulateDumpSharedSpace: public VM_Operation { 391 private: 392 ClassLoaderData* _loader_data; 393 GrowableArray<Klass*> *_class_promote_order; 394 VirtualSpace _md_vs; 395 VirtualSpace _mc_vs; 396 397 public: 398 VM_PopulateDumpSharedSpace(ClassLoaderData* loader_data, 399 GrowableArray<Klass*> *class_promote_order) : 400 _loader_data(loader_data) { 401 402 // Split up and initialize the misc code and data spaces 403 ReservedSpace* shared_rs = MetaspaceShared::shared_rs(); 404 int metadata_size = SharedReadOnlySize+SharedReadWriteSize; 405 ReservedSpace shared_ro_rw = shared_rs->first_part(metadata_size); 406 ReservedSpace misc_section = shared_rs->last_part(metadata_size); 407 408 // Now split into misc sections. 409 ReservedSpace md_rs = misc_section.first_part(SharedMiscDataSize); 410 ReservedSpace mc_rs = misc_section.last_part(SharedMiscDataSize); 411 _md_vs.initialize(md_rs, SharedMiscDataSize); 412 _mc_vs.initialize(mc_rs, SharedMiscCodeSize); 413 _class_promote_order = class_promote_order; 414 } 415 416 VMOp_Type type() const { return VMOp_PopulateDumpSharedSpace; } 417 void doit(); // outline because gdb sucks 418 }; // class VM_PopulateDumpSharedSpace 419 420 421 void VM_PopulateDumpSharedSpace::doit() { 422 Thread* THREAD = VMThread::vm_thread(); 423 NOT_PRODUCT(SystemDictionary::verify();) 424 // The following guarantee is meant to ensure that no loader constraints 425 // exist yet, since the constraints table is not shared. This becomes 426 // more important now that we don't re-initialize vtables/itables for 427 // shared classes at runtime, where constraints were previously created. 428 guarantee(SystemDictionary::constraints()->number_of_entries() == 0, 429 "loader constraints are not saved"); 430 guarantee(SystemDictionary::placeholders()->number_of_entries() == 0, 431 "placeholders are not saved"); 432 // Revisit and implement this if we prelink method handle call sites: 433 guarantee(SystemDictionary::invoke_method_table() == NULL || 434 SystemDictionary::invoke_method_table()->number_of_entries() == 0, 435 "invoke method table is not saved"); 436 437 // At this point, many classes have been loaded. 438 // Gather systemDictionary classes in a global array and do everything to 439 // that so we don't have to walk the SystemDictionary again. 440 _global_klass_objects = new GrowableArray<Klass*>(1000); 441 Universe::basic_type_classes_do(collect_classes); 442 SystemDictionary::classes_do(collect_classes); 443 444 tty->print_cr("Number of classes %d", _global_klass_objects->length()); 445 446 // Update all the fingerprints in the shared methods. 447 tty->print("Calculating fingerprints ... "); 448 calculate_fingerprints(); 449 tty->print_cr("done. "); 450 451 // Remove all references outside the metadata 452 tty->print("Removing unshareable information ... "); 453 remove_unshareable_in_classes(); 454 tty->print_cr("done. "); 455 456 // Set up the share data and shared code segments. 457 char* md_low = _md_vs.low(); 458 char* md_top = md_low; 459 char* md_end = _md_vs.high(); 460 char* mc_low = _mc_vs.low(); 461 char* mc_top = mc_low; 462 char* mc_end = _mc_vs.high(); 463 464 // Reserve space for the list of Klass*s whose vtables are used 465 // for patching others as needed. 466 467 void** vtbl_list = (void**)md_top; 468 int vtbl_list_size = MetaspaceShared::vtbl_list_size; 469 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); 470 471 md_top += vtbl_list_size * sizeof(void*); 472 void* vtable = md_top; 473 474 // Reserve space for a new dummy vtable for klass objects in the 475 // heap. Generate self-patching vtable entries. 476 477 MetaspaceShared::generate_vtable_methods(vtbl_list, &vtable, 478 &md_top, md_end, 479 &mc_top, mc_end); 480 481 // Reorder the system dictionary. (Moving the symbols affects 482 // how the hash table indices are calculated.) 483 // Not doing this either. 484 485 SystemDictionary::reorder_dictionary(); 486 487 NOT_PRODUCT(SystemDictionary::verify();) 488 489 // Copy the the symbol table, and the system dictionary to the shared 490 // space in usable form. Copy the hastable 491 // buckets first [read-write], then copy the linked lists of entries 492 // [read-only]. 493 494 SymbolTable::reverse(md_top); 495 NOT_PRODUCT(SymbolTable::verify()); 496 SymbolTable::copy_buckets(&md_top, md_end); 497 498 SystemDictionary::reverse(); 499 SystemDictionary::copy_buckets(&md_top, md_end); 500 501 ClassLoader::verify(); 502 ClassLoader::copy_package_info_buckets(&md_top, md_end); 503 ClassLoader::verify(); 504 505 SymbolTable::copy_table(&md_top, md_end); 506 SystemDictionary::copy_table(&md_top, md_end); 507 ClassLoader::verify(); 508 ClassLoader::copy_package_info_table(&md_top, md_end); 509 ClassLoader::verify(); 510 511 // Write the other data to the output array. 512 WriteClosure wc(md_top, md_end); 513 MetaspaceShared::serialize(&wc); 514 md_top = wc.get_top(); 515 516 // Print shared spaces all the time 517 const char* fmt = "%s space: %9d [ %4.1f%% of total] out of %9d bytes [%4.1f%% used] at " PTR_FORMAT; 518 Metaspace* ro_space = _loader_data->ro_metaspace(); 519 Metaspace* rw_space = _loader_data->rw_metaspace(); 520 521 // Allocated size of each space (may not be all occupied) 522 const size_t ro_alloced = ro_space->capacity_bytes_slow(Metaspace::NonClassType); 523 const size_t rw_alloced = rw_space->capacity_bytes_slow(Metaspace::NonClassType); 524 const size_t md_alloced = md_end-md_low; 525 const size_t mc_alloced = mc_end-mc_low; 526 const size_t total_alloced = ro_alloced + rw_alloced + md_alloced + mc_alloced; 527 528 // Occupied size of each space. 529 const size_t ro_bytes = ro_space->used_bytes_slow(Metaspace::NonClassType); 530 const size_t rw_bytes = rw_space->used_bytes_slow(Metaspace::NonClassType); 531 const size_t md_bytes = size_t(md_top - md_low); 532 const size_t mc_bytes = size_t(mc_top - mc_low); 533 534 // Percent of total size 535 const size_t total_bytes = ro_bytes + rw_bytes + md_bytes + mc_bytes; 536 const double ro_t_perc = ro_bytes / double(total_bytes) * 100.0; 537 const double rw_t_perc = rw_bytes / double(total_bytes) * 100.0; 538 const double md_t_perc = md_bytes / double(total_bytes) * 100.0; 539 const double mc_t_perc = mc_bytes / double(total_bytes) * 100.0; 540 541 // Percent of fullness of each space 542 const double ro_u_perc = ro_bytes / double(ro_alloced) * 100.0; 543 const double rw_u_perc = rw_bytes / double(rw_alloced) * 100.0; 544 const double md_u_perc = md_bytes / double(md_alloced) * 100.0; 545 const double mc_u_perc = mc_bytes / double(mc_alloced) * 100.0; 546 const double total_u_perc = total_bytes / double(total_alloced) * 100.0; 547 548 tty->print_cr(fmt, "ro", ro_bytes, ro_t_perc, ro_alloced, ro_u_perc, ro_space->bottom()); 549 tty->print_cr(fmt, "rw", rw_bytes, rw_t_perc, rw_alloced, rw_u_perc, rw_space->bottom()); 550 tty->print_cr(fmt, "md", md_bytes, md_t_perc, md_alloced, md_u_perc, md_low); 551 tty->print_cr(fmt, "mc", mc_bytes, mc_t_perc, mc_alloced, mc_u_perc, mc_low); 552 tty->print_cr("total : %9d [100.0%% of total] out of %9d bytes [%4.1f%% used]", 553 total_bytes, total_alloced, total_u_perc); 554 555 // Update the vtable pointers in all of the Klass objects in the 556 // heap. They should point to newly generated vtable. 557 patch_klass_vtables(vtbl_list, vtable); 558 559 // dunno what this is for. 560 char* saved_vtbl = (char*)os::malloc(vtbl_list_size * sizeof(void*), mtClass); 561 memmove(saved_vtbl, vtbl_list, vtbl_list_size * sizeof(void*)); 562 memset(vtbl_list, 0, vtbl_list_size * sizeof(void*)); 563 564 // Create and write the archive file that maps the shared spaces. 565 566 FileMapInfo* mapinfo = new FileMapInfo(); 567 mapinfo->populate_header(MetaspaceShared::max_alignment()); 568 569 // Pass 1 - update file offsets in header. 570 mapinfo->write_header(); 571 mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); 572 mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); 573 mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), 574 pointer_delta(md_top, _md_vs.low(), sizeof(char)), 575 SharedMiscDataSize, 576 false, false); 577 mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), 578 pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), 579 SharedMiscCodeSize, 580 true, true); 581 582 // Pass 2 - write data. 583 mapinfo->open_for_write(); 584 mapinfo->write_header(); 585 mapinfo->write_space(MetaspaceShared::ro, _loader_data->ro_metaspace(), true); 586 mapinfo->write_space(MetaspaceShared::rw, _loader_data->rw_metaspace(), false); 587 mapinfo->write_region(MetaspaceShared::md, _md_vs.low(), 588 pointer_delta(md_top, _md_vs.low(), sizeof(char)), 589 SharedMiscDataSize, 590 false, false); 591 mapinfo->write_region(MetaspaceShared::mc, _mc_vs.low(), 592 pointer_delta(mc_top, _mc_vs.low(), sizeof(char)), 593 SharedMiscCodeSize, 594 true, true); 595 mapinfo->close(); 596 597 memmove(vtbl_list, saved_vtbl, vtbl_list_size * sizeof(void*)); 598 599 if (PrintSharedSpaces) { 600 DumpAllocClosure dac; 601 dac.iterate_metaspace(_loader_data->ro_metaspace(), DumpAllocClosure::RO); 602 dac.iterate_metaspace(_loader_data->rw_metaspace(), DumpAllocClosure::RW); 603 604 dac.dump_stats(int(ro_bytes), int(rw_bytes), int(md_bytes), int(mc_bytes)); 605 } 606 } 607 608 static void link_shared_classes(Klass* obj, TRAPS) { 609 Klass* k = obj; 610 if (k->oop_is_instance()) { 611 InstanceKlass* ik = (InstanceKlass*) k; 612 // Link the class to cause the bytecodes to be rewritten and the 613 // cpcache to be created. 614 if (ik->init_state() < InstanceKlass::linked) { 615 ik->link_class(THREAD); 616 guarantee(!HAS_PENDING_EXCEPTION, "exception in class rewriting"); 617 } 618 } 619 } 620 621 622 // Support for a simple checksum of the contents of the class list 623 // file to prevent trivial tampering. The algorithm matches that in 624 // the MakeClassList program used by the J2SE build process. 625 #define JSUM_SEED ((jlong)CONST64(0xcafebabebabecafe)) 626 static jlong 627 jsum(jlong start, const char *buf, const int len) 628 { 629 jlong h = start; 630 char *p = (char *)buf, *e = p + len; 631 while (p < e) { 632 char c = *p++; 633 if (c <= ' ') { 634 /* Skip spaces and control characters */ 635 continue; 636 } 637 h = 31 * h + c; 638 } 639 return h; 640 } 641 642 // Preload classes from a list, populate the shared spaces and dump to a 643 // file. 644 void MetaspaceShared::preload_and_dump(TRAPS) { 645 TraceTime timer("Dump Shared Spaces", TraceStartupTime); 646 ResourceMark rm; 647 648 // Lock out GC - is it necessary? I don't think we care. 649 No_GC_Verifier no_gc; 650 651 // Preload classes to be shared. 652 // Should use some os:: method rather than fopen() here. aB. 653 // Construct the path to the class list (in jre/lib) 654 // Walk up two directories from the location of the VM and 655 // optionally tack on "lib" (depending on platform) 656 char class_list_path[JVM_MAXPATHLEN]; 657 os::jvm_path(class_list_path, sizeof(class_list_path)); 658 for (int i = 0; i < 3; i++) { 659 char *end = strrchr(class_list_path, *os::file_separator()); 660 if (end != NULL) *end = '\0'; 661 } 662 int class_list_path_len = (int)strlen(class_list_path); 663 if (class_list_path_len >= 3) { 664 if (strcmp(class_list_path + class_list_path_len - 3, "lib") != 0) { 665 strcat(class_list_path, os::file_separator()); 666 strcat(class_list_path, "lib"); 667 } 668 } 669 strcat(class_list_path, os::file_separator()); 670 strcat(class_list_path, "classlist"); 671 672 FILE* file = fopen(class_list_path, "r"); 673 if (file != NULL) { 674 jlong computed_jsum = JSUM_SEED; 675 jlong file_jsum = 0; 676 677 char class_name[256]; 678 int class_count = 0; 679 GrowableArray<Klass*>* class_promote_order = new GrowableArray<Klass*>(); 680 681 // sun.io.Converters 682 static const char obj_array_sig[] = "[[Ljava/lang/Object;"; 683 SymbolTable::new_permanent_symbol(obj_array_sig, THREAD); 684 685 // java.util.HashMap 686 static const char map_entry_array_sig[] = "[Ljava/util/Map$Entry;"; 687 SymbolTable::new_permanent_symbol(map_entry_array_sig, THREAD); 688 689 tty->print("Loading classes to share ... "); 690 while ((fgets(class_name, sizeof class_name, file)) != NULL) { 691 if (*class_name == '#') { 692 jint fsh, fsl; 693 if (sscanf(class_name, "# %8x%8x\n", &fsh, &fsl) == 2) { 694 file_jsum = ((jlong)(fsh) << 32) | (fsl & 0xffffffff); 695 } 696 697 continue; 698 } 699 // Remove trailing newline 700 size_t name_len = strlen(class_name); 701 class_name[name_len-1] = '\0'; 702 703 computed_jsum = jsum(computed_jsum, class_name, (const int)name_len - 1); 704 705 // Got a class name - load it. 706 TempNewSymbol class_name_symbol = SymbolTable::new_permanent_symbol(class_name, THREAD); 707 guarantee(!HAS_PENDING_EXCEPTION, "Exception creating a symbol."); 708 Klass* klass = SystemDictionary::resolve_or_null(class_name_symbol, 709 THREAD); 710 guarantee(!HAS_PENDING_EXCEPTION, "Exception resolving a class."); 711 if (klass != NULL) { 712 if (PrintSharedSpaces && Verbose && WizardMode) { 713 tty->print_cr("Shared spaces preloaded: %s", class_name); 714 } 715 716 717 InstanceKlass* ik = InstanceKlass::cast(klass); 718 719 // Should be class load order as per -XX:+TraceClassLoadingPreorder 720 class_promote_order->append(ik); 721 722 // Link the class to cause the bytecodes to be rewritten and the 723 // cpcache to be created. The linking is done as soon as classes 724 // are loaded in order that the related data structures (klass and 725 // cpCache) are located together. 726 727 if (ik->init_state() < InstanceKlass::linked) { 728 ik->link_class(THREAD); 729 guarantee(!(HAS_PENDING_EXCEPTION), "exception in class rewriting"); 730 } 731 732 // TODO: Resolve klasses in constant pool 733 ik->constants()->resolve_class_constants(THREAD); 734 735 class_count++; 736 } else { 737 if (PrintSharedSpaces && Verbose && WizardMode) { 738 tty->cr(); 739 tty->print_cr(" Preload failed: %s", class_name); 740 } 741 } 742 file_jsum = 0; // Checksum must be on last line of file 743 } 744 if (computed_jsum != file_jsum) { 745 tty->cr(); 746 tty->print_cr("Preload failed: checksum of class list was incorrect."); 747 exit(1); 748 } 749 750 tty->print_cr("done. "); 751 752 if (PrintSharedSpaces) { 753 tty->print_cr("Shared spaces: preloaded %d classes", class_count); 754 } 755 756 // Rewrite and unlink classes. 757 tty->print("Rewriting and linking classes ... "); 758 759 // Link any classes which got missed. (It's not quite clear why 760 // they got missed.) This iteration would be unsafe if we weren't 761 // single-threaded at this point; however we can't do it on the VM 762 // thread because it requires object allocation. 763 SystemDictionary::classes_do(link_shared_classes, CATCH); 764 tty->print_cr("done. "); 765 766 // Create and dump the shared spaces. Everything so far is loaded 767 // with the null class loader. 768 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data(); 769 VM_PopulateDumpSharedSpace op(loader_data, class_promote_order); 770 VMThread::execute(&op); 771 772 } else { 773 char errmsg[JVM_MAXPATHLEN]; 774 os::lasterror(errmsg, JVM_MAXPATHLEN); 775 tty->print_cr("Loading classlist failed: %s", errmsg); 776 exit(1); 777 } 778 779 // Since various initialization steps have been undone by this process, 780 // it is not reasonable to continue running a java process. 781 exit(0); 782 } 783 784 785 // Closure for serializing initialization data in from a data area 786 // (ptr_array) read from the shared file. 787 788 class ReadClosure : public SerializeClosure { 789 private: 790 intptr_t** _ptr_array; 791 792 inline intptr_t nextPtr() { 793 return *(*_ptr_array)++; 794 } 795 796 public: 797 ReadClosure(intptr_t** ptr_array) { _ptr_array = ptr_array; } 798 799 void do_ptr(void** p) { 800 assert(*p == NULL, "initializing previous initialized pointer."); 801 intptr_t obj = nextPtr(); 802 assert((intptr_t)obj >= 0 || (intptr_t)obj < -100, 803 "hit tag while initializing ptrs."); 804 *p = (void*)obj; 805 } 806 807 void do_tag(int tag) { 808 int old_tag; 809 old_tag = (int)(intptr_t)nextPtr(); 810 // do_int(&old_tag); 811 assert(tag == old_tag, "old tag doesn't match"); 812 FileMapInfo::assert_mark(tag == old_tag); 813 } 814 815 void do_region(u_char* start, size_t size) { 816 assert((intptr_t)start % sizeof(intptr_t) == 0, "bad alignment"); 817 assert(size % sizeof(intptr_t) == 0, "bad size"); 818 do_tag((int)size); 819 while (size > 0) { 820 *(intptr_t*)start = nextPtr(); 821 start += sizeof(intptr_t); 822 size -= sizeof(intptr_t); 823 } 824 } 825 826 bool reading() const { return true; } 827 }; 828 829 // Return true if given address is in the mapped shared space. 830 bool MetaspaceShared::is_in_shared_space(const void* p) { 831 return UseSharedSpaces && FileMapInfo::current_info()->is_in_shared_space(p); 832 } 833 834 void MetaspaceShared::print_shared_spaces() { 835 if (UseSharedSpaces) { 836 FileMapInfo::current_info()->print_shared_spaces(); 837 } 838 } 839 840 841 // Map shared spaces at requested addresses and return if succeeded. 842 // Need to keep the bounds of the ro and rw space for the Metaspace::contains 843 // call, or is_in_shared_space. 844 bool MetaspaceShared::map_shared_spaces(FileMapInfo* mapinfo) { 845 size_t image_alignment = mapinfo->alignment(); 846 847 #ifndef _WINDOWS 848 // Map in the shared memory and then map the regions on top of it. 849 // On Windows, don't map the memory here because it will cause the 850 // mappings of the regions to fail. 851 ReservedSpace shared_rs = mapinfo->reserve_shared_memory(); 852 if (!shared_rs.is_reserved()) return false; 853 #endif 854 855 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces"); 856 857 char* _ro_base = NULL; 858 char* _rw_base = NULL; 859 char* _md_base = NULL; 860 char* _mc_base = NULL; 861 862 // Map each shared region 863 if ((_ro_base = mapinfo->map_region(ro)) != NULL && 864 (_rw_base = mapinfo->map_region(rw)) != NULL && 865 (_md_base = mapinfo->map_region(md)) != NULL && 866 (_mc_base = mapinfo->map_region(mc)) != NULL && 867 (image_alignment == (size_t)max_alignment())) { 868 // Success (no need to do anything) 869 return true; 870 } else { 871 // If there was a failure in mapping any of the spaces, unmap the ones 872 // that succeeded 873 if (_ro_base != NULL) mapinfo->unmap_region(ro); 874 if (_rw_base != NULL) mapinfo->unmap_region(rw); 875 if (_md_base != NULL) mapinfo->unmap_region(md); 876 if (_mc_base != NULL) mapinfo->unmap_region(mc); 877 #ifndef _WINDOWS 878 // Release the entire mapped region 879 shared_rs.release(); 880 #endif 881 // If -Xshare:on is specified, print out the error message and exit VM, 882 // otherwise, set UseSharedSpaces to false and continue. 883 if (RequireSharedSpaces) { 884 vm_exit_during_initialization("Unable to use shared archive.", NULL); 885 } else { 886 FLAG_SET_DEFAULT(UseSharedSpaces, false); 887 } 888 return false; 889 } 890 } 891 892 // Read the miscellaneous data from the shared file, and 893 // serialize it out to its various destinations. 894 895 void MetaspaceShared::initialize_shared_spaces() { 896 FileMapInfo *mapinfo = FileMapInfo::current_info(); 897 898 char* buffer = mapinfo->region_base(md); 899 900 // Skip over (reserve space for) a list of addresses of C++ vtables 901 // for Klass objects. They get filled in later. 902 903 void** vtbl_list = (void**)buffer; 904 buffer += MetaspaceShared::vtbl_list_size * sizeof(void*); 905 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size); 906 907 // Skip over (reserve space for) dummy C++ vtables Klass objects. 908 // They are used as is. 909 910 intptr_t vtable_size = *(intptr_t*)buffer; 911 buffer += sizeof(intptr_t); 912 buffer += vtable_size; 913 914 // Create the symbol table using the bucket array at this spot in the 915 // misc data space. Since the symbol table is often modified, this 916 // region (of mapped pages) will be copy-on-write. 917 918 int symbolTableLen = *(intptr_t*)buffer; 919 buffer += sizeof(intptr_t); 920 int number_of_entries = *(intptr_t*)buffer; 921 buffer += sizeof(intptr_t); 922 SymbolTable::create_table((HashtableBucket<mtSymbol>*)buffer, symbolTableLen, 923 number_of_entries); 924 buffer += symbolTableLen; 925 926 // Create the shared dictionary using the bucket array at this spot in 927 // the misc data space. Since the shared dictionary table is never 928 // modified, this region (of mapped pages) will be (effectively, if 929 // not explicitly) read-only. 930 931 int sharedDictionaryLen = *(intptr_t*)buffer; 932 buffer += sizeof(intptr_t); 933 number_of_entries = *(intptr_t*)buffer; 934 buffer += sizeof(intptr_t); 935 SystemDictionary::set_shared_dictionary((HashtableBucket<mtClass>*)buffer, 936 sharedDictionaryLen, 937 number_of_entries); 938 buffer += sharedDictionaryLen; 939 940 // Create the package info table using the bucket array at this spot in 941 // the misc data space. Since the package info table is never 942 // modified, this region (of mapped pages) will be (effectively, if 943 // not explicitly) read-only. 944 945 int pkgInfoLen = *(intptr_t*)buffer; 946 buffer += sizeof(intptr_t); 947 number_of_entries = *(intptr_t*)buffer; 948 buffer += sizeof(intptr_t); 949 ClassLoader::create_package_info_table((HashtableBucket<mtClass>*)buffer, pkgInfoLen, 950 number_of_entries); 951 buffer += pkgInfoLen; 952 ClassLoader::verify(); 953 954 // The following data in the shared misc data region are the linked 955 // list elements (HashtableEntry objects) for the symbol table, string 956 // table, and shared dictionary. The heap objects refered to by the 957 // symbol table, string table, and shared dictionary are permanent and 958 // unmovable. Since new entries added to the string and symbol tables 959 // are always added at the beginning of the linked lists, THESE LINKED 960 // LIST ELEMENTS ARE READ-ONLY. 961 962 int len = *(intptr_t*)buffer; // skip over symbol table entries 963 buffer += sizeof(intptr_t); 964 buffer += len; 965 966 len = *(intptr_t*)buffer; // skip over shared dictionary entries 967 buffer += sizeof(intptr_t); 968 buffer += len; 969 970 len = *(intptr_t*)buffer; // skip over package info table entries 971 buffer += sizeof(intptr_t); 972 buffer += len; 973 974 len = *(intptr_t*)buffer; // skip over package info table char[] arrays. 975 buffer += sizeof(intptr_t); 976 buffer += len; 977 978 intptr_t* array = (intptr_t*)buffer; 979 ReadClosure rc(&array); 980 serialize(&rc); 981 982 // Close the mapinfo file 983 mapinfo->close(); 984 } 985 986 // JVM/TI RedefineClasses() support: 987 bool MetaspaceShared::remap_shared_readonly_as_readwrite() { 988 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint"); 989 990 if (UseSharedSpaces) { 991 // remap the shared readonly space to shared readwrite, private 992 FileMapInfo* mapinfo = FileMapInfo::current_info(); 993 if (!mapinfo->remap_shared_readonly_as_readwrite()) { 994 return false; 995 } 996 } 997 return true; 998 }