1 /* 2 * Copyright (c) 2005, 2023, 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/classLoaderData.inline.hpp" 27 #include "classfile/classLoaderDataGraph.hpp" 28 #include "classfile/javaClasses.inline.hpp" 29 #include "classfile/symbolTable.hpp" 30 #include "classfile/vmClasses.hpp" 31 #include "classfile/vmSymbols.hpp" 32 #include "gc/shared/gcLocker.hpp" 33 #include "gc/shared/gcVMOperations.hpp" 34 #include "gc/shared/workerThread.hpp" 35 #include "jfr/jfrEvents.hpp" 36 #include "jvm.h" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/resourceArea.hpp" 39 #include "memory/universe.hpp" 40 #include "oops/klass.inline.hpp" 41 #include "oops/objArrayKlass.hpp" 42 #include "oops/objArrayOop.inline.hpp" 43 #include "oops/oop.inline.hpp" 44 #include "oops/typeArrayOop.inline.hpp" 45 #include "runtime/frame.inline.hpp" 46 #include "runtime/handles.inline.hpp" 47 #include "runtime/javaCalls.hpp" 48 #include "runtime/javaThread.inline.hpp" 49 #include "runtime/jniHandles.hpp" 50 #include "runtime/os.hpp" 51 #include "runtime/reflectionUtils.hpp" 52 #include "runtime/threads.hpp" 53 #include "runtime/threadSMR.hpp" 54 #include "runtime/vframe.hpp" 55 #include "runtime/vmOperations.hpp" 56 #include "runtime/vmThread.hpp" 57 #include "services/heapDumper.hpp" 58 #include "services/heapDumperCompression.hpp" 59 #include "services/threadService.hpp" 60 #include "utilities/macros.hpp" 61 #include "utilities/ostream.hpp" 62 63 /* 64 * HPROF binary format - description copied from: 65 * src/share/demo/jvmti/hprof/hprof_io.c 66 * 67 * 68 * header "JAVA PROFILE 1.0.2" (0-terminated) 69 * 70 * u4 size of identifiers. Identifiers are used to represent 71 * UTF8 strings, objects, stack traces, etc. They usually 72 * have the same size as host pointers. 73 * u4 high word 74 * u4 low word number of milliseconds since 0:00 GMT, 1/1/70 75 * [record]* a sequence of records. 76 * 77 * 78 * Record format: 79 * 80 * u1 a TAG denoting the type of the record 81 * u4 number of *microseconds* since the time stamp in the 82 * header. (wraps around in a little more than an hour) 83 * u4 number of bytes *remaining* in the record. Note that 84 * this number excludes the tag and the length field itself. 85 * [u1]* BODY of the record (a sequence of bytes) 86 * 87 * 88 * The following TAGs are supported: 89 * 90 * TAG BODY notes 91 *---------------------------------------------------------- 92 * HPROF_UTF8 a UTF8-encoded name 93 * 94 * id name ID 95 * [u1]* UTF8 characters (no trailing zero) 96 * 97 * HPROF_LOAD_CLASS a newly loaded class 98 * 99 * u4 class serial number (> 0) 100 * id class object ID 101 * u4 stack trace serial number 102 * id class name ID 103 * 104 * HPROF_UNLOAD_CLASS an unloading class 105 * 106 * u4 class serial_number 107 * 108 * HPROF_FRAME a Java stack frame 109 * 110 * id stack frame ID 111 * id method name ID 112 * id method signature ID 113 * id source file name ID 114 * u4 class serial number 115 * i4 line number. >0: normal 116 * -1: unknown 117 * -2: compiled method 118 * -3: native method 119 * 120 * HPROF_TRACE a Java stack trace 121 * 122 * u4 stack trace serial number 123 * u4 thread serial number 124 * u4 number of frames 125 * [id]* stack frame IDs 126 * 127 * 128 * HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC 129 * 130 * u2 flags 0x0001: incremental vs. complete 131 * 0x0002: sorted by allocation vs. live 132 * 0x0004: whether to force a GC 133 * u4 cutoff ratio 134 * u4 total live bytes 135 * u4 total live instances 136 * u8 total bytes allocated 137 * u8 total instances allocated 138 * u4 number of sites that follow 139 * [u1 is_array: 0: normal object 140 * 2: object array 141 * 4: boolean array 142 * 5: char array 143 * 6: float array 144 * 7: double array 145 * 8: byte array 146 * 9: short array 147 * 10: int array 148 * 11: long array 149 * u4 class serial number (may be zero during startup) 150 * u4 stack trace serial number 151 * u4 number of bytes alive 152 * u4 number of instances alive 153 * u4 number of bytes allocated 154 * u4]* number of instance allocated 155 * 156 * HPROF_START_THREAD a newly started thread. 157 * 158 * u4 thread serial number (> 0) 159 * id thread object ID 160 * u4 stack trace serial number 161 * id thread name ID 162 * id thread group name ID 163 * id thread group parent name ID 164 * 165 * HPROF_END_THREAD a terminating thread. 166 * 167 * u4 thread serial number 168 * 169 * HPROF_HEAP_SUMMARY heap summary 170 * 171 * u4 total live bytes 172 * u4 total live instances 173 * u8 total bytes allocated 174 * u8 total instances allocated 175 * 176 * HPROF_HEAP_DUMP denote a heap dump 177 * 178 * [heap dump sub-records]* 179 * 180 * There are four kinds of heap dump sub-records: 181 * 182 * u1 sub-record type 183 * 184 * HPROF_GC_ROOT_UNKNOWN unknown root 185 * 186 * id object ID 187 * 188 * HPROF_GC_ROOT_THREAD_OBJ thread object 189 * 190 * id thread object ID (may be 0 for a 191 * thread newly attached through JNI) 192 * u4 thread sequence number 193 * u4 stack trace sequence number 194 * 195 * HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root 196 * 197 * id object ID 198 * id JNI global ref ID 199 * 200 * HPROF_GC_ROOT_JNI_LOCAL JNI local ref 201 * 202 * id object ID 203 * u4 thread serial number 204 * u4 frame # in stack trace (-1 for empty) 205 * 206 * HPROF_GC_ROOT_JAVA_FRAME Java stack frame 207 * 208 * id object ID 209 * u4 thread serial number 210 * u4 frame # in stack trace (-1 for empty) 211 * 212 * HPROF_GC_ROOT_NATIVE_STACK Native stack 213 * 214 * id object ID 215 * u4 thread serial number 216 * 217 * HPROF_GC_ROOT_STICKY_CLASS System class 218 * 219 * id object ID 220 * 221 * HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block 222 * 223 * id object ID 224 * u4 thread serial number 225 * 226 * HPROF_GC_ROOT_MONITOR_USED Busy monitor 227 * 228 * id object ID 229 * 230 * HPROF_GC_CLASS_DUMP dump of a class object 231 * 232 * id class object ID 233 * u4 stack trace serial number 234 * id super class object ID 235 * id class loader object ID 236 * id signers object ID 237 * id protection domain object ID 238 * id reserved 239 * id reserved 240 * 241 * u4 instance size (in bytes) 242 * 243 * u2 size of constant pool 244 * [u2, constant pool index, 245 * ty, type 246 * 2: object 247 * 4: boolean 248 * 5: char 249 * 6: float 250 * 7: double 251 * 8: byte 252 * 9: short 253 * 10: int 254 * 11: long 255 * vl]* and value 256 * 257 * u2 number of static fields 258 * [id, static field name, 259 * ty, type, 260 * vl]* and value 261 * 262 * u2 number of inst. fields (not inc. super) 263 * [id, instance field name, 264 * ty]* type 265 * 266 * HPROF_GC_INSTANCE_DUMP dump of a normal object 267 * 268 * id object ID 269 * u4 stack trace serial number 270 * id class object ID 271 * u4 number of bytes that follow 272 * [vl]* instance field values (class, followed 273 * by super, super's super ...) 274 * 275 * HPROF_GC_OBJ_ARRAY_DUMP dump of an object array 276 * 277 * id array object ID 278 * u4 stack trace serial number 279 * u4 number of elements 280 * id array class ID 281 * [id]* elements 282 * 283 * HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array 284 * 285 * id array object ID 286 * u4 stack trace serial number 287 * u4 number of elements 288 * u1 element type 289 * 4: boolean array 290 * 5: char array 291 * 6: float array 292 * 7: double array 293 * 8: byte array 294 * 9: short array 295 * 10: int array 296 * 11: long array 297 * [u1]* elements 298 * 299 * HPROF_CPU_SAMPLES a set of sample traces of running threads 300 * 301 * u4 total number of samples 302 * u4 # of traces 303 * [u4 # of samples 304 * u4]* stack trace serial number 305 * 306 * HPROF_CONTROL_SETTINGS the settings of on/off switches 307 * 308 * u4 0x00000001: alloc traces on/off 309 * 0x00000002: cpu sampling on/off 310 * u2 stack trace depth 311 * 312 * 313 * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally 314 * be generated as a sequence of heap dump segments. This sequence is 315 * terminated by an end record. The additional tags allowed by format 316 * "JAVA PROFILE 1.0.2" are: 317 * 318 * HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment 319 * 320 * [heap dump sub-records]* 321 * The same sub-record types allowed by HPROF_HEAP_DUMP 322 * 323 * HPROF_HEAP_DUMP_END denotes the end of a heap dump 324 * 325 */ 326 327 328 // HPROF tags 329 330 enum hprofTag : u1 { 331 // top-level records 332 HPROF_UTF8 = 0x01, 333 HPROF_LOAD_CLASS = 0x02, 334 HPROF_UNLOAD_CLASS = 0x03, 335 HPROF_FRAME = 0x04, 336 HPROF_TRACE = 0x05, 337 HPROF_ALLOC_SITES = 0x06, 338 HPROF_HEAP_SUMMARY = 0x07, 339 HPROF_START_THREAD = 0x0A, 340 HPROF_END_THREAD = 0x0B, 341 HPROF_HEAP_DUMP = 0x0C, 342 HPROF_CPU_SAMPLES = 0x0D, 343 HPROF_CONTROL_SETTINGS = 0x0E, 344 345 // 1.0.2 record types 346 HPROF_HEAP_DUMP_SEGMENT = 0x1C, 347 HPROF_HEAP_DUMP_END = 0x2C, 348 349 // field types 350 HPROF_ARRAY_OBJECT = 0x01, 351 HPROF_NORMAL_OBJECT = 0x02, 352 HPROF_BOOLEAN = 0x04, 353 HPROF_CHAR = 0x05, 354 HPROF_FLOAT = 0x06, 355 HPROF_DOUBLE = 0x07, 356 HPROF_BYTE = 0x08, 357 HPROF_SHORT = 0x09, 358 HPROF_INT = 0x0A, 359 HPROF_LONG = 0x0B, 360 361 // data-dump sub-records 362 HPROF_GC_ROOT_UNKNOWN = 0xFF, 363 HPROF_GC_ROOT_JNI_GLOBAL = 0x01, 364 HPROF_GC_ROOT_JNI_LOCAL = 0x02, 365 HPROF_GC_ROOT_JAVA_FRAME = 0x03, 366 HPROF_GC_ROOT_NATIVE_STACK = 0x04, 367 HPROF_GC_ROOT_STICKY_CLASS = 0x05, 368 HPROF_GC_ROOT_THREAD_BLOCK = 0x06, 369 HPROF_GC_ROOT_MONITOR_USED = 0x07, 370 HPROF_GC_ROOT_THREAD_OBJ = 0x08, 371 HPROF_GC_CLASS_DUMP = 0x20, 372 HPROF_GC_INSTANCE_DUMP = 0x21, 373 HPROF_GC_OBJ_ARRAY_DUMP = 0x22, 374 HPROF_GC_PRIM_ARRAY_DUMP = 0x23 375 }; 376 377 // Default stack trace ID (used for dummy HPROF_TRACE record) 378 enum { 379 STACK_TRACE_ID = 1, 380 INITIAL_CLASS_COUNT = 200 381 }; 382 383 // Supports I/O operations for a dump 384 // Base class for dump and parallel dump 385 class AbstractDumpWriter : public StackObj { 386 protected: 387 enum { 388 io_buffer_max_size = 1*M, 389 io_buffer_max_waste = 10*K, 390 dump_segment_header_size = 9 391 }; 392 393 char* _buffer; // internal buffer 394 size_t _size; 395 size_t _pos; 396 397 bool _in_dump_segment; // Are we currently in a dump segment? 398 bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size? 399 DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record. 400 DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record(). 401 402 virtual void flush(bool force = false) = 0; 403 404 char* buffer() const { return _buffer; } 405 size_t buffer_size() const { return _size; } 406 void set_position(size_t pos) { _pos = pos; } 407 408 // Can be called if we have enough room in the buffer. 409 void write_fast(const void* s, size_t len); 410 411 // Returns true if we have enough room in the buffer for 'len' bytes. 412 bool can_write_fast(size_t len); 413 414 void write_address(address a); 415 416 public: 417 AbstractDumpWriter() : 418 _buffer(nullptr), 419 _size(io_buffer_max_size), 420 _pos(0), 421 _in_dump_segment(false) { } 422 423 // total number of bytes written to the disk 424 virtual julong bytes_written() const = 0; 425 virtual char const* error() const = 0; 426 427 size_t position() const { return _pos; } 428 // writer functions 429 virtual void write_raw(const void* s, size_t len); 430 void write_u1(u1 x); 431 void write_u2(u2 x); 432 void write_u4(u4 x); 433 void write_u8(u8 x); 434 void write_objectID(oop o); 435 void write_rootID(oop* p); 436 void write_symbolID(Symbol* o); 437 void write_classID(Klass* k); 438 void write_id(u4 x); 439 440 // Start a new sub-record. Starts a new heap dump segment if needed. 441 void start_sub_record(u1 tag, u4 len); 442 // Ends the current sub-record. 443 void end_sub_record(); 444 // Finishes the current dump segment if not already finished. 445 void finish_dump_segment(bool force_flush = false); 446 // Refresh to get new buffer 447 void refresh() { 448 assert (_in_dump_segment ==false, "Sanity check"); 449 _buffer = nullptr; 450 _size = io_buffer_max_size; 451 _pos = 0; 452 // Force flush to guarantee data from parallel dumper are written. 453 flush(true); 454 } 455 // Called when finished to release the threads. 456 virtual void deactivate() = 0; 457 }; 458 459 void AbstractDumpWriter::write_fast(const void* s, size_t len) { 460 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large"); 461 assert(buffer_size() - position() >= len, "Must fit"); 462 debug_only(_sub_record_left -= len); 463 memcpy(buffer() + position(), s, len); 464 set_position(position() + len); 465 } 466 467 bool AbstractDumpWriter::can_write_fast(size_t len) { 468 return buffer_size() - position() >= len; 469 } 470 471 // write raw bytes 472 void AbstractDumpWriter::write_raw(const void* s, size_t len) { 473 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large"); 474 debug_only(_sub_record_left -= len); 475 476 // flush buffer to make room. 477 while (len > buffer_size() - position()) { 478 assert(!_in_dump_segment || _is_huge_sub_record, 479 "Cannot overflow in non-huge sub-record."); 480 size_t to_write = buffer_size() - position(); 481 memcpy(buffer() + position(), s, to_write); 482 s = (void*) ((char*) s + to_write); 483 len -= to_write; 484 set_position(position() + to_write); 485 flush(); 486 } 487 488 memcpy(buffer() + position(), s, len); 489 set_position(position() + len); 490 } 491 492 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup. 493 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \ 494 else write_raw((p), (len)); } while (0) 495 496 void AbstractDumpWriter::write_u1(u1 x) { 497 WRITE_KNOWN_TYPE(&x, 1); 498 } 499 500 void AbstractDumpWriter::write_u2(u2 x) { 501 u2 v; 502 Bytes::put_Java_u2((address)&v, x); 503 WRITE_KNOWN_TYPE(&v, 2); 504 } 505 506 void AbstractDumpWriter::write_u4(u4 x) { 507 u4 v; 508 Bytes::put_Java_u4((address)&v, x); 509 WRITE_KNOWN_TYPE(&v, 4); 510 } 511 512 void AbstractDumpWriter::write_u8(u8 x) { 513 u8 v; 514 Bytes::put_Java_u8((address)&v, x); 515 WRITE_KNOWN_TYPE(&v, 8); 516 } 517 518 void AbstractDumpWriter::write_address(address a) { 519 #ifdef _LP64 520 write_u8((u8)a); 521 #else 522 write_u4((u4)a); 523 #endif 524 } 525 526 void AbstractDumpWriter::write_objectID(oop o) { 527 write_address(cast_from_oop<address>(o)); 528 } 529 530 void AbstractDumpWriter::write_rootID(oop* p) { 531 write_address((address)p); 532 } 533 534 void AbstractDumpWriter::write_symbolID(Symbol* s) { 535 write_address((address)((uintptr_t)s)); 536 } 537 538 void AbstractDumpWriter::write_id(u4 x) { 539 #ifdef _LP64 540 write_u8((u8) x); 541 #else 542 write_u4(x); 543 #endif 544 } 545 546 // We use java mirror as the class ID 547 void AbstractDumpWriter::write_classID(Klass* k) { 548 write_objectID(k->java_mirror()); 549 } 550 551 void AbstractDumpWriter::finish_dump_segment(bool force_flush) { 552 if (_in_dump_segment) { 553 assert(_sub_record_left == 0, "Last sub-record not written completely"); 554 assert(_sub_record_ended, "sub-record must have ended"); 555 556 // Fix up the dump segment length if we haven't written a huge sub-record last 557 // (in which case the segment length was already set to the correct value initially). 558 if (!_is_huge_sub_record) { 559 assert(position() > dump_segment_header_size, "Dump segment should have some content"); 560 Bytes::put_Java_u4((address) (buffer() + 5), 561 (u4) (position() - dump_segment_header_size)); 562 } else { 563 // Finish process huge sub record 564 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file. 565 _is_huge_sub_record = false; 566 } 567 568 _in_dump_segment = false; 569 flush(force_flush); 570 } 571 } 572 573 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) { 574 if (!_in_dump_segment) { 575 if (position() > 0) { 576 flush(); 577 } 578 579 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start"); 580 581 write_u1(HPROF_HEAP_DUMP_SEGMENT); 582 write_u4(0); // timestamp 583 // Will be fixed up later if we add more sub-records. If this is a huge sub-record, 584 // this is already the correct length, since we don't add more sub-records. 585 write_u4(len); 586 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsistent size!"); 587 _in_dump_segment = true; 588 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size; 589 } else if (_is_huge_sub_record || (len > buffer_size() - position())) { 590 // This object will not fit in completely or the last sub-record was huge. 591 // Finish the current segment and try again. 592 finish_dump_segment(); 593 start_sub_record(tag, len); 594 595 return; 596 } 597 598 debug_only(_sub_record_left = len); 599 debug_only(_sub_record_ended = false); 600 601 write_u1(tag); 602 } 603 604 void AbstractDumpWriter::end_sub_record() { 605 assert(_in_dump_segment, "must be in dump segment"); 606 assert(_sub_record_left == 0, "sub-record not written completely"); 607 assert(!_sub_record_ended, "Must not have ended yet"); 608 debug_only(_sub_record_ended = true); 609 } 610 611 // Supports I/O operations for a dump 612 613 class DumpWriter : public AbstractDumpWriter { 614 private: 615 CompressionBackend _backend; // Does the actual writing. 616 protected: 617 void flush(bool force = false) override; 618 619 public: 620 // Takes ownership of the writer and compressor. 621 DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor); 622 623 // total number of bytes written to the disk 624 julong bytes_written() const override { return (julong) _backend.get_written(); } 625 626 char const* error() const override { return _backend.error(); } 627 628 // Called by threads used for parallel writing. 629 void writer_loop() { _backend.thread_loop(); } 630 // Called when finish to release the threads. 631 void deactivate() override { flush(); _backend.deactivate(); } 632 // Get the backend pointer, used by parallel dump writer. 633 CompressionBackend* backend_ptr() { return &_backend; } 634 635 }; 636 637 // Check for error after constructing the object and destroy it in case of an error. 638 DumpWriter::DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor) : 639 AbstractDumpWriter(), 640 _backend(writer, compressor, io_buffer_max_size, io_buffer_max_waste) { 641 flush(); 642 } 643 644 // flush any buffered bytes to the file 645 void DumpWriter::flush(bool force) { 646 _backend.get_new_buffer(&_buffer, &_pos, &_size, force); 647 } 648 649 // Buffer queue used for parallel dump. 650 struct ParWriterBufferQueueElem { 651 char* _buffer; 652 size_t _used; 653 ParWriterBufferQueueElem* _next; 654 }; 655 656 class ParWriterBufferQueue : public CHeapObj<mtInternal> { 657 private: 658 ParWriterBufferQueueElem* _head; 659 ParWriterBufferQueueElem* _tail; 660 uint _length; 661 public: 662 ParWriterBufferQueue() : _head(nullptr), _tail(nullptr), _length(0) { } 663 664 void enqueue(ParWriterBufferQueueElem* entry) { 665 if (_head == nullptr) { 666 assert(is_empty() && _tail == nullptr, "Sanity check"); 667 _head = _tail = entry; 668 } else { 669 assert ((_tail->_next == nullptr && _tail->_buffer != nullptr), "Buffer queue is polluted"); 670 _tail->_next = entry; 671 _tail = entry; 672 } 673 _length++; 674 assert(_tail->_next == nullptr, "Buffer queue is polluted"); 675 } 676 677 ParWriterBufferQueueElem* dequeue() { 678 if (_head == nullptr) return nullptr; 679 ParWriterBufferQueueElem* entry = _head; 680 assert (entry->_buffer != nullptr, "polluted buffer in writer list"); 681 _head = entry->_next; 682 if (_head == nullptr) { 683 _tail = nullptr; 684 } 685 entry->_next = nullptr; 686 _length--; 687 return entry; 688 } 689 690 bool is_empty() { 691 return _length == 0; 692 } 693 694 uint length() { return _length; } 695 }; 696 697 // Support parallel heap dump. 698 class ParDumpWriter : public AbstractDumpWriter { 699 private: 700 // Lock used to guarantee the integrity of multiple buffers writing. 701 static Monitor* _lock; 702 // Pointer of backend from global DumpWriter. 703 CompressionBackend* _backend_ptr; 704 char const * _err; 705 ParWriterBufferQueue* _buffer_queue; 706 size_t _internal_buffer_used; 707 char* _buffer_base; 708 bool _split_data; 709 static const uint BackendFlushThreshold = 2; 710 protected: 711 void flush(bool force = false) override { 712 assert(_pos != 0, "must not be zero"); 713 if (_pos != 0) { 714 refresh_buffer(); 715 } 716 717 if (_split_data || _is_huge_sub_record) { 718 return; 719 } 720 721 if (should_flush_buf_list(force)) { 722 assert(!_in_dump_segment && !_split_data && !_is_huge_sub_record, "incomplete data send to backend!\n"); 723 flush_to_backend(force); 724 } 725 } 726 727 public: 728 // Check for error after constructing the object and destroy it in case of an error. 729 ParDumpWriter(DumpWriter* dw) : 730 AbstractDumpWriter(), 731 _backend_ptr(dw->backend_ptr()), 732 _buffer_queue((new (std::nothrow) ParWriterBufferQueue())), 733 _buffer_base(nullptr), 734 _split_data(false) { 735 // prepare internal buffer 736 allocate_internal_buffer(); 737 } 738 739 ~ParDumpWriter() { 740 assert(_buffer_queue != nullptr, "Sanity check"); 741 assert((_internal_buffer_used == 0) && (_buffer_queue->is_empty()), 742 "All data must be send to backend"); 743 if (_buffer_base != nullptr) { 744 os::free(_buffer_base); 745 _buffer_base = nullptr; 746 } 747 delete _buffer_queue; 748 _buffer_queue = nullptr; 749 } 750 751 // total number of bytes written to the disk 752 julong bytes_written() const override { return (julong) _backend_ptr->get_written(); } 753 char const* error() const override { return _err == nullptr ? _backend_ptr->error() : _err; } 754 755 static void before_work() { 756 assert(_lock == nullptr, "ParDumpWriter lock must be initialized only once"); 757 _lock = new (std::nothrow) PaddedMonitor(Mutex::safepoint, "ParallelHProfWriter_lock"); 758 } 759 760 static void after_work() { 761 assert(_lock != nullptr, "ParDumpWriter lock is not initialized"); 762 delete _lock; 763 _lock = nullptr; 764 } 765 766 // write raw bytes 767 void write_raw(const void* s, size_t len) override { 768 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large"); 769 debug_only(_sub_record_left -= len); 770 assert(!_split_data, "Invalid split data"); 771 _split_data = true; 772 // flush buffer to make room. 773 while (len > buffer_size() - position()) { 774 assert(!_in_dump_segment || _is_huge_sub_record, 775 "Cannot overflow in non-huge sub-record."); 776 size_t to_write = buffer_size() - position(); 777 memcpy(buffer() + position(), s, to_write); 778 s = (void*) ((char*) s + to_write); 779 len -= to_write; 780 set_position(position() + to_write); 781 flush(); 782 } 783 _split_data = false; 784 memcpy(buffer() + position(), s, len); 785 set_position(position() + len); 786 } 787 788 void deactivate() override { flush(true); _backend_ptr->deactivate(); } 789 790 private: 791 void allocate_internal_buffer() { 792 assert(_buffer_queue != nullptr, "Internal buffer queue is not ready when allocate internal buffer"); 793 assert(_buffer == nullptr && _buffer_base == nullptr, "current buffer must be null before allocate"); 794 _buffer_base = _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal); 795 if (_buffer == nullptr) { 796 set_error("Could not allocate buffer for writer"); 797 return; 798 } 799 _pos = 0; 800 _internal_buffer_used = 0; 801 _size = io_buffer_max_size; 802 } 803 804 void set_error(char const* new_error) { 805 if ((new_error != nullptr) && (_err == nullptr)) { 806 _err = new_error; 807 } 808 } 809 810 // Add buffer to internal list 811 void refresh_buffer() { 812 size_t expected_total = _internal_buffer_used + _pos; 813 if (expected_total < io_buffer_max_size - io_buffer_max_waste) { 814 // reuse current buffer. 815 _internal_buffer_used = expected_total; 816 assert(_size - _pos == io_buffer_max_size - expected_total, "illegal resize of buffer"); 817 _size -= _pos; 818 _buffer += _pos; 819 _pos = 0; 820 821 return; 822 } 823 // It is not possible here that expected_total is larger than io_buffer_max_size because 824 // of limitation in write_xxx(). 825 assert(expected_total <= io_buffer_max_size, "buffer overflow"); 826 assert(_buffer - _buffer_base <= io_buffer_max_size, "internal buffer overflow"); 827 ParWriterBufferQueueElem* entry = 828 (ParWriterBufferQueueElem*)os::malloc(sizeof(ParWriterBufferQueueElem), mtInternal); 829 if (entry == nullptr) { 830 set_error("Heap dumper can allocate memory"); 831 return; 832 } 833 entry->_buffer = _buffer_base; 834 entry->_used = expected_total; 835 entry->_next = nullptr; 836 // add to internal buffer queue 837 _buffer_queue->enqueue(entry); 838 _buffer_base =_buffer = nullptr; 839 allocate_internal_buffer(); 840 } 841 842 void reclaim_entry(ParWriterBufferQueueElem* entry) { 843 assert(entry != nullptr && entry->_buffer != nullptr, "Invalid entry to reclaim"); 844 os::free(entry->_buffer); 845 entry->_buffer = nullptr; 846 os::free(entry); 847 } 848 849 void flush_buffer(char* buffer, size_t used) { 850 assert(_lock->owner() == Thread::current(), "flush buffer must hold lock"); 851 size_t max = io_buffer_max_size; 852 // get_new_buffer 853 _backend_ptr->flush_external_buffer(buffer, used, max); 854 } 855 856 bool should_flush_buf_list(bool force) { 857 return force || _buffer_queue->length() > BackendFlushThreshold; 858 } 859 860 void flush_to_backend(bool force) { 861 // Guarantee there is only one writer updating the backend buffers. 862 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag); 863 while (!_buffer_queue->is_empty()) { 864 ParWriterBufferQueueElem* entry = _buffer_queue->dequeue(); 865 flush_buffer(entry->_buffer, entry->_used); 866 // Delete buffer and entry. 867 reclaim_entry(entry); 868 entry = nullptr; 869 } 870 assert(_pos == 0, "available buffer must be empty before flush"); 871 // Flush internal buffer. 872 if (_internal_buffer_used > 0) { 873 flush_buffer(_buffer_base, _internal_buffer_used); 874 os::free(_buffer_base); 875 _pos = 0; 876 _internal_buffer_used = 0; 877 _buffer_base = _buffer = nullptr; 878 // Allocate internal buffer for future use. 879 allocate_internal_buffer(); 880 } 881 } 882 }; 883 884 Monitor* ParDumpWriter::_lock = nullptr; 885 886 // Support class with a collection of functions used when dumping the heap 887 888 class DumperSupport : AllStatic { 889 public: 890 891 // write a header of the given type 892 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len); 893 894 // returns hprof tag for the given type signature 895 static hprofTag sig2tag(Symbol* sig); 896 // returns hprof tag for the given basic type 897 static hprofTag type2tag(BasicType type); 898 // Returns the size of the data to write. 899 static u4 sig2size(Symbol* sig); 900 901 // returns the size of the instance of the given class 902 static u4 instance_size(Klass* k); 903 904 // dump a jfloat 905 static void dump_float(AbstractDumpWriter* writer, jfloat f); 906 // dump a jdouble 907 static void dump_double(AbstractDumpWriter* writer, jdouble d); 908 // dumps the raw value of the given field 909 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset); 910 // returns the size of the static fields; also counts the static fields 911 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count); 912 // dumps static fields of the given class 913 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k); 914 // dump the raw values of the instance fields of the given object 915 static void dump_instance_fields(AbstractDumpWriter* writer, oop o); 916 // get the count of the instance fields for a given class 917 static u2 get_instance_fields_count(InstanceKlass* ik); 918 // dumps the definition of the instance fields for a given class 919 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k); 920 // creates HPROF_GC_INSTANCE_DUMP record for the given object 921 static void dump_instance(AbstractDumpWriter* writer, oop o); 922 // creates HPROF_GC_CLASS_DUMP record for the given instance class 923 static void dump_instance_class(AbstractDumpWriter* writer, Klass* k); 924 // creates HPROF_GC_CLASS_DUMP record for a given array class 925 static void dump_array_class(AbstractDumpWriter* writer, Klass* k); 926 927 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array 928 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array); 929 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array 930 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array); 931 // create HPROF_FRAME record for the given method and bci 932 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci); 933 934 // check if we need to truncate an array 935 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size); 936 937 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record 938 static void end_of_dump(AbstractDumpWriter* writer); 939 940 static oop mask_dormant_archived_object(oop o) { 941 if (o != nullptr && o->klass()->java_mirror() == nullptr) { 942 // Ignore this object since the corresponding java mirror is not loaded. 943 // Might be a dormant archive object. 944 return nullptr; 945 } else { 946 return o; 947 } 948 } 949 }; 950 951 // write a header of the given type 952 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) { 953 writer->write_u1(tag); 954 writer->write_u4(0); // current ticks 955 writer->write_u4(len); 956 } 957 958 // returns hprof tag for the given type signature 959 hprofTag DumperSupport::sig2tag(Symbol* sig) { 960 switch (sig->char_at(0)) { 961 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT; 962 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT; 963 case JVM_SIGNATURE_BYTE : return HPROF_BYTE; 964 case JVM_SIGNATURE_CHAR : return HPROF_CHAR; 965 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT; 966 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE; 967 case JVM_SIGNATURE_INT : return HPROF_INT; 968 case JVM_SIGNATURE_LONG : return HPROF_LONG; 969 case JVM_SIGNATURE_SHORT : return HPROF_SHORT; 970 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN; 971 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE; 972 } 973 } 974 975 hprofTag DumperSupport::type2tag(BasicType type) { 976 switch (type) { 977 case T_BYTE : return HPROF_BYTE; 978 case T_CHAR : return HPROF_CHAR; 979 case T_FLOAT : return HPROF_FLOAT; 980 case T_DOUBLE : return HPROF_DOUBLE; 981 case T_INT : return HPROF_INT; 982 case T_LONG : return HPROF_LONG; 983 case T_SHORT : return HPROF_SHORT; 984 case T_BOOLEAN : return HPROF_BOOLEAN; 985 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE; 986 } 987 } 988 989 u4 DumperSupport::sig2size(Symbol* sig) { 990 switch (sig->char_at(0)) { 991 case JVM_SIGNATURE_CLASS: 992 case JVM_SIGNATURE_ARRAY: return sizeof(address); 993 case JVM_SIGNATURE_BOOLEAN: 994 case JVM_SIGNATURE_BYTE: return 1; 995 case JVM_SIGNATURE_SHORT: 996 case JVM_SIGNATURE_CHAR: return 2; 997 case JVM_SIGNATURE_INT: 998 case JVM_SIGNATURE_FLOAT: return 4; 999 case JVM_SIGNATURE_LONG: 1000 case JVM_SIGNATURE_DOUBLE: return 8; 1001 default: ShouldNotReachHere(); /* to shut up compiler */ return 0; 1002 } 1003 } 1004 1005 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20 1006 T to; 1007 static_assert(sizeof(to) == sizeof(from), "must be of the same size"); 1008 memcpy(&to, &from, sizeof(to)); 1009 return to; 1010 } 1011 1012 // dump a jfloat 1013 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) { 1014 if (g_isnan(f)) { 1015 writer->write_u4(0x7fc00000); // collapsing NaNs 1016 } else { 1017 writer->write_u4(bit_cast<u4>(f)); 1018 } 1019 } 1020 1021 // dump a jdouble 1022 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) { 1023 if (g_isnan(d)) { 1024 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs 1025 } else { 1026 writer->write_u8(bit_cast<u8>(d)); 1027 } 1028 } 1029 1030 // dumps the raw value of the given field 1031 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) { 1032 switch (type) { 1033 case JVM_SIGNATURE_CLASS : 1034 case JVM_SIGNATURE_ARRAY : { 1035 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset); 1036 if (o != nullptr && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == nullptr) { 1037 ResourceMark rm; 1038 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)", 1039 p2i(o), o->klass()->external_name(), 1040 p2i(obj), obj->klass()->external_name()); 1041 } 1042 o = mask_dormant_archived_object(o); 1043 assert(oopDesc::is_oop_or_null(o), "Expected an oop or nullptr at " PTR_FORMAT, p2i(o)); 1044 writer->write_objectID(o); 1045 break; 1046 } 1047 case JVM_SIGNATURE_BYTE : { 1048 jbyte b = obj->byte_field(offset); 1049 writer->write_u1(b); 1050 break; 1051 } 1052 case JVM_SIGNATURE_CHAR : { 1053 jchar c = obj->char_field(offset); 1054 writer->write_u2(c); 1055 break; 1056 } 1057 case JVM_SIGNATURE_SHORT : { 1058 jshort s = obj->short_field(offset); 1059 writer->write_u2(s); 1060 break; 1061 } 1062 case JVM_SIGNATURE_FLOAT : { 1063 jfloat f = obj->float_field(offset); 1064 dump_float(writer, f); 1065 break; 1066 } 1067 case JVM_SIGNATURE_DOUBLE : { 1068 jdouble d = obj->double_field(offset); 1069 dump_double(writer, d); 1070 break; 1071 } 1072 case JVM_SIGNATURE_INT : { 1073 jint i = obj->int_field(offset); 1074 writer->write_u4(i); 1075 break; 1076 } 1077 case JVM_SIGNATURE_LONG : { 1078 jlong l = obj->long_field(offset); 1079 writer->write_u8(l); 1080 break; 1081 } 1082 case JVM_SIGNATURE_BOOLEAN : { 1083 jboolean b = obj->bool_field(offset); 1084 writer->write_u1(b); 1085 break; 1086 } 1087 default : { 1088 ShouldNotReachHere(); 1089 break; 1090 } 1091 } 1092 } 1093 1094 // returns the size of the instance of the given class 1095 u4 DumperSupport::instance_size(Klass* k) { 1096 InstanceKlass* ik = InstanceKlass::cast(k); 1097 u4 size = 0; 1098 1099 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) { 1100 if (!fld.access_flags().is_static()) { 1101 size += sig2size(fld.signature()); 1102 } 1103 } 1104 return size; 1105 } 1106 1107 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) { 1108 field_count = 0; 1109 u4 size = 0; 1110 1111 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) { 1112 if (fldc.access_flags().is_static()) { 1113 field_count++; 1114 size += sig2size(fldc.signature()); 1115 } 1116 } 1117 1118 // Add in resolved_references which is referenced by the cpCache 1119 // The resolved_references is an array per InstanceKlass holding the 1120 // strings and other oops resolved from the constant pool. 1121 oop resolved_references = ik->constants()->resolved_references_or_null(); 1122 if (resolved_references != nullptr) { 1123 field_count++; 1124 size += sizeof(address); 1125 1126 // Add in the resolved_references of the used previous versions of the class 1127 // in the case of RedefineClasses 1128 InstanceKlass* prev = ik->previous_versions(); 1129 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) { 1130 field_count++; 1131 size += sizeof(address); 1132 prev = prev->previous_versions(); 1133 } 1134 } 1135 1136 // We write the value itself plus a name and a one byte type tag per field. 1137 return size + field_count * (sizeof(address) + 1); 1138 } 1139 1140 // dumps static fields of the given class 1141 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) { 1142 InstanceKlass* ik = InstanceKlass::cast(k); 1143 1144 // dump the field descriptors and raw values 1145 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) { 1146 if (fld.access_flags().is_static()) { 1147 Symbol* sig = fld.signature(); 1148 1149 writer->write_symbolID(fld.name()); // name 1150 writer->write_u1(sig2tag(sig)); // type 1151 1152 // value 1153 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset()); 1154 } 1155 } 1156 1157 // Add resolved_references for each class that has them 1158 oop resolved_references = ik->constants()->resolved_references_or_null(); 1159 if (resolved_references != nullptr) { 1160 writer->write_symbolID(vmSymbols::resolved_references_name()); // name 1161 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type 1162 writer->write_objectID(resolved_references); 1163 1164 // Also write any previous versions 1165 InstanceKlass* prev = ik->previous_versions(); 1166 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) { 1167 writer->write_symbolID(vmSymbols::resolved_references_name()); // name 1168 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type 1169 writer->write_objectID(prev->constants()->resolved_references()); 1170 prev = prev->previous_versions(); 1171 } 1172 } 1173 } 1174 1175 // dump the raw values of the instance fields of the given object 1176 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o) { 1177 InstanceKlass* ik = InstanceKlass::cast(o->klass()); 1178 1179 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) { 1180 if (!fld.access_flags().is_static()) { 1181 Symbol* sig = fld.signature(); 1182 dump_field_value(writer, sig->char_at(0), o, fld.offset()); 1183 } 1184 } 1185 } 1186 1187 // dumps the definition of the instance fields for a given class 1188 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) { 1189 u2 field_count = 0; 1190 1191 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) { 1192 if (!fldc.access_flags().is_static()) field_count++; 1193 } 1194 1195 return field_count; 1196 } 1197 1198 // dumps the definition of the instance fields for a given class 1199 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) { 1200 InstanceKlass* ik = InstanceKlass::cast(k); 1201 1202 // dump the field descriptors 1203 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) { 1204 if (!fld.access_flags().is_static()) { 1205 Symbol* sig = fld.signature(); 1206 1207 writer->write_symbolID(fld.name()); // name 1208 writer->write_u1(sig2tag(sig)); // type 1209 } 1210 } 1211 } 1212 1213 // creates HPROF_GC_INSTANCE_DUMP record for the given object 1214 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o) { 1215 InstanceKlass* ik = InstanceKlass::cast(o->klass()); 1216 u4 is = instance_size(ik); 1217 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is; 1218 1219 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size); 1220 writer->write_objectID(o); 1221 writer->write_u4(STACK_TRACE_ID); 1222 1223 // class ID 1224 writer->write_classID(ik); 1225 1226 // number of bytes that follow 1227 writer->write_u4(is); 1228 1229 // field values 1230 dump_instance_fields(writer, o); 1231 1232 writer->end_sub_record(); 1233 } 1234 1235 // creates HPROF_GC_CLASS_DUMP record for the given instance class 1236 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) { 1237 InstanceKlass* ik = InstanceKlass::cast(k); 1238 1239 // We can safepoint and do a heap dump at a point where we have a Klass, 1240 // but no java mirror class has been setup for it. So we need to check 1241 // that the class is at least loaded, to avoid crash from a null mirror. 1242 if (!ik->is_loaded()) { 1243 return; 1244 } 1245 1246 u2 static_fields_count = 0; 1247 u4 static_size = get_static_fields_size(ik, static_fields_count); 1248 u2 instance_fields_count = get_instance_fields_count(ik); 1249 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1); 1250 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size; 1251 1252 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size); 1253 1254 // class ID 1255 writer->write_classID(ik); 1256 writer->write_u4(STACK_TRACE_ID); 1257 1258 // super class ID 1259 InstanceKlass* java_super = ik->java_super(); 1260 if (java_super == nullptr) { 1261 writer->write_objectID(oop(nullptr)); 1262 } else { 1263 writer->write_classID(java_super); 1264 } 1265 1266 writer->write_objectID(ik->class_loader()); 1267 writer->write_objectID(ik->signers()); 1268 writer->write_objectID(ik->protection_domain()); 1269 1270 // reserved 1271 writer->write_objectID(oop(nullptr)); 1272 writer->write_objectID(oop(nullptr)); 1273 1274 // instance size 1275 writer->write_u4(DumperSupport::instance_size(ik)); 1276 1277 // size of constant pool - ignored by HAT 1.1 1278 writer->write_u2(0); 1279 1280 // static fields 1281 writer->write_u2(static_fields_count); 1282 dump_static_fields(writer, ik); 1283 1284 // description of instance fields 1285 writer->write_u2(instance_fields_count); 1286 dump_instance_field_descriptors(writer, ik); 1287 1288 writer->end_sub_record(); 1289 } 1290 1291 // creates HPROF_GC_CLASS_DUMP record for the given array class 1292 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) { 1293 InstanceKlass* ik = nullptr; // bottom class for object arrays, null for primitive type arrays 1294 if (k->is_objArray_klass()) { 1295 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass(); 1296 assert(bk != nullptr, "checking"); 1297 if (bk->is_instance_klass()) { 1298 ik = InstanceKlass::cast(bk); 1299 } 1300 } 1301 1302 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2; 1303 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size); 1304 writer->write_classID(k); 1305 writer->write_u4(STACK_TRACE_ID); 1306 1307 // super class of array classes is java.lang.Object 1308 InstanceKlass* java_super = k->java_super(); 1309 assert(java_super != nullptr, "checking"); 1310 writer->write_classID(java_super); 1311 1312 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->class_loader()); 1313 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->signers()); 1314 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->protection_domain()); 1315 1316 writer->write_objectID(oop(nullptr)); // reserved 1317 writer->write_objectID(oop(nullptr)); 1318 writer->write_u4(0); // instance size 1319 writer->write_u2(0); // constant pool 1320 writer->write_u2(0); // static fields 1321 writer->write_u2(0); // instance fields 1322 1323 writer->end_sub_record(); 1324 1325 } 1326 1327 // Hprof uses an u4 as record length field, 1328 // which means we need to truncate arrays that are too long. 1329 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) { 1330 BasicType type = ArrayKlass::cast(array->klass())->element_type(); 1331 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type"); 1332 1333 int length = array->length(); 1334 1335 int type_size; 1336 if (type == T_OBJECT) { 1337 type_size = sizeof(address); 1338 } else { 1339 type_size = type2aelembytes(type); 1340 } 1341 1342 size_t length_in_bytes = (size_t)length * type_size; 1343 uint max_bytes = max_juint - header_size; 1344 1345 if (length_in_bytes > max_bytes) { 1346 length = max_bytes / type_size; 1347 length_in_bytes = (size_t)length * type_size; 1348 1349 warning("cannot dump array of type %s[] with length %d; truncating to length %d", 1350 type2name_tab[type], array->length(), length); 1351 } 1352 return length; 1353 } 1354 1355 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array 1356 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) { 1357 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID) 1358 short header_size = 1 + 2 * 4 + 2 * sizeof(address); 1359 int length = calculate_array_max_length(writer, array, header_size); 1360 u4 size = header_size + length * sizeof(address); 1361 1362 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size); 1363 writer->write_objectID(array); 1364 writer->write_u4(STACK_TRACE_ID); 1365 writer->write_u4(length); 1366 1367 // array class ID 1368 writer->write_classID(array->klass()); 1369 1370 // [id]* elements 1371 for (int index = 0; index < length; index++) { 1372 oop o = array->obj_at(index); 1373 if (o != nullptr && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == nullptr) { 1374 ResourceMark rm; 1375 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)", 1376 p2i(o), o->klass()->external_name(), 1377 p2i(array), array->klass()->external_name()); 1378 } 1379 o = mask_dormant_archived_object(o); 1380 writer->write_objectID(o); 1381 } 1382 1383 writer->end_sub_record(); 1384 } 1385 1386 #define WRITE_ARRAY(Array, Type, Size, Length) \ 1387 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); } 1388 1389 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array 1390 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) { 1391 BasicType type = TypeArrayKlass::cast(array->klass())->element_type(); 1392 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) 1393 short header_size = 2 * 1 + 2 * 4 + sizeof(address); 1394 1395 int length = calculate_array_max_length(writer, array, header_size); 1396 int type_size = type2aelembytes(type); 1397 u4 length_in_bytes = (u4)length * type_size; 1398 u4 size = header_size + length_in_bytes; 1399 1400 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size); 1401 writer->write_objectID(array); 1402 writer->write_u4(STACK_TRACE_ID); 1403 writer->write_u4(length); 1404 writer->write_u1(type2tag(type)); 1405 1406 // nothing to copy 1407 if (length == 0) { 1408 writer->end_sub_record(); 1409 return; 1410 } 1411 1412 // If the byte ordering is big endian then we can copy most types directly 1413 1414 switch (type) { 1415 case T_INT : { 1416 if (Endian::is_Java_byte_ordering_different()) { 1417 WRITE_ARRAY(array, int, u4, length); 1418 } else { 1419 writer->write_raw(array->int_at_addr(0), length_in_bytes); 1420 } 1421 break; 1422 } 1423 case T_BYTE : { 1424 writer->write_raw(array->byte_at_addr(0), length_in_bytes); 1425 break; 1426 } 1427 case T_CHAR : { 1428 if (Endian::is_Java_byte_ordering_different()) { 1429 WRITE_ARRAY(array, char, u2, length); 1430 } else { 1431 writer->write_raw(array->char_at_addr(0), length_in_bytes); 1432 } 1433 break; 1434 } 1435 case T_SHORT : { 1436 if (Endian::is_Java_byte_ordering_different()) { 1437 WRITE_ARRAY(array, short, u2, length); 1438 } else { 1439 writer->write_raw(array->short_at_addr(0), length_in_bytes); 1440 } 1441 break; 1442 } 1443 case T_BOOLEAN : { 1444 if (Endian::is_Java_byte_ordering_different()) { 1445 WRITE_ARRAY(array, bool, u1, length); 1446 } else { 1447 writer->write_raw(array->bool_at_addr(0), length_in_bytes); 1448 } 1449 break; 1450 } 1451 case T_LONG : { 1452 if (Endian::is_Java_byte_ordering_different()) { 1453 WRITE_ARRAY(array, long, u8, length); 1454 } else { 1455 writer->write_raw(array->long_at_addr(0), length_in_bytes); 1456 } 1457 break; 1458 } 1459 1460 // handle float/doubles in a special value to ensure than NaNs are 1461 // written correctly. TO DO: Check if we can avoid this on processors that 1462 // use IEEE 754. 1463 1464 case T_FLOAT : { 1465 for (int i = 0; i < length; i++) { 1466 dump_float(writer, array->float_at(i)); 1467 } 1468 break; 1469 } 1470 case T_DOUBLE : { 1471 for (int i = 0; i < length; i++) { 1472 dump_double(writer, array->double_at(i)); 1473 } 1474 break; 1475 } 1476 default : ShouldNotReachHere(); 1477 } 1478 1479 writer->end_sub_record(); 1480 } 1481 1482 // create a HPROF_FRAME record of the given Method* and bci 1483 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer, 1484 int frame_serial_num, 1485 int class_serial_num, 1486 Method* m, 1487 int bci) { 1488 int line_number; 1489 if (m->is_native()) { 1490 line_number = -3; // native frame 1491 } else { 1492 line_number = m->line_number_from_bci(bci); 1493 } 1494 1495 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4)); 1496 writer->write_id(frame_serial_num); // frame serial number 1497 writer->write_symbolID(m->name()); // method's name 1498 writer->write_symbolID(m->signature()); // method's signature 1499 1500 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass"); 1501 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name 1502 writer->write_u4(class_serial_num); // class serial number 1503 writer->write_u4((u4) line_number); // line number 1504 } 1505 1506 1507 // Support class used to generate HPROF_UTF8 records from the entries in the 1508 // SymbolTable. 1509 1510 class SymbolTableDumper : public SymbolClosure { 1511 private: 1512 AbstractDumpWriter* _writer; 1513 AbstractDumpWriter* writer() const { return _writer; } 1514 public: 1515 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; } 1516 void do_symbol(Symbol** p); 1517 }; 1518 1519 void SymbolTableDumper::do_symbol(Symbol** p) { 1520 ResourceMark rm; 1521 Symbol* sym = *p; 1522 int len = sym->utf8_length(); 1523 if (len > 0) { 1524 char* s = sym->as_utf8(); 1525 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len); 1526 writer()->write_symbolID(sym); 1527 writer()->write_raw(s, len); 1528 } 1529 } 1530 1531 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records 1532 1533 class JNILocalsDumper : public OopClosure { 1534 private: 1535 AbstractDumpWriter* _writer; 1536 u4 _thread_serial_num; 1537 int _frame_num; 1538 AbstractDumpWriter* writer() const { return _writer; } 1539 public: 1540 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) { 1541 _writer = writer; 1542 _thread_serial_num = thread_serial_num; 1543 _frame_num = -1; // default - empty stack 1544 } 1545 void set_frame_number(int n) { _frame_num = n; } 1546 void do_oop(oop* obj_p); 1547 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); } 1548 }; 1549 1550 1551 void JNILocalsDumper::do_oop(oop* obj_p) { 1552 // ignore null handles 1553 oop o = *obj_p; 1554 if (o != nullptr) { 1555 u4 size = 1 + sizeof(address) + 4 + 4; 1556 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size); 1557 writer()->write_objectID(o); 1558 writer()->write_u4(_thread_serial_num); 1559 writer()->write_u4((u4)_frame_num); 1560 writer()->end_sub_record(); 1561 } 1562 } 1563 1564 1565 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records 1566 1567 class JNIGlobalsDumper : public OopClosure { 1568 private: 1569 AbstractDumpWriter* _writer; 1570 AbstractDumpWriter* writer() const { return _writer; } 1571 1572 public: 1573 JNIGlobalsDumper(AbstractDumpWriter* writer) { 1574 _writer = writer; 1575 } 1576 void do_oop(oop* obj_p); 1577 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); } 1578 }; 1579 1580 void JNIGlobalsDumper::do_oop(oop* obj_p) { 1581 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p); 1582 1583 // ignore these 1584 if (o == nullptr) return; 1585 // we ignore global ref to symbols and other internal objects 1586 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) { 1587 u4 size = 1 + 2 * sizeof(address); 1588 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size); 1589 writer()->write_objectID(o); 1590 writer()->write_rootID(obj_p); // global ref ID 1591 writer()->end_sub_record(); 1592 } 1593 }; 1594 1595 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records 1596 1597 class StickyClassDumper : public KlassClosure { 1598 private: 1599 AbstractDumpWriter* _writer; 1600 AbstractDumpWriter* writer() const { return _writer; } 1601 public: 1602 StickyClassDumper(AbstractDumpWriter* writer) { 1603 _writer = writer; 1604 } 1605 void do_klass(Klass* k) { 1606 if (k->is_instance_klass()) { 1607 InstanceKlass* ik = InstanceKlass::cast(k); 1608 u4 size = 1 + sizeof(address); 1609 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size); 1610 writer()->write_classID(ik); 1611 writer()->end_sub_record(); 1612 } 1613 } 1614 }; 1615 1616 // Large object heap dump support. 1617 // To avoid memory consumption, when dumping large objects such as huge array and 1618 // large objects whose size are larger than LARGE_OBJECT_DUMP_THRESHOLD, the scanned 1619 // partial object/array data will be sent to the backend directly instead of caching 1620 // the whole object/array in the internal buffer. 1621 // The HeapDumpLargeObjectList is used to save the large object when dumper scans 1622 // the heap. The large objects could be added (push) parallelly by multiple dumpers, 1623 // But they will be removed (popped) serially only by the VM thread. 1624 class HeapDumpLargeObjectList : public CHeapObj<mtInternal> { 1625 private: 1626 class HeapDumpLargeObjectListElem : public CHeapObj<mtInternal> { 1627 public: 1628 HeapDumpLargeObjectListElem(oop obj) : _obj(obj), _next(nullptr) { } 1629 oop _obj; 1630 HeapDumpLargeObjectListElem* _next; 1631 }; 1632 1633 volatile HeapDumpLargeObjectListElem* _head; 1634 1635 public: 1636 HeapDumpLargeObjectList() : _head(nullptr) { } 1637 1638 void atomic_push(oop obj) { 1639 assert (obj != nullptr, "sanity check"); 1640 HeapDumpLargeObjectListElem* entry = new HeapDumpLargeObjectListElem(obj); 1641 if (entry == nullptr) { 1642 warning("failed to allocate element for large object list"); 1643 return; 1644 } 1645 assert (entry->_obj != nullptr, "sanity check"); 1646 while (true) { 1647 volatile HeapDumpLargeObjectListElem* old_head = Atomic::load_acquire(&_head); 1648 HeapDumpLargeObjectListElem* new_head = entry; 1649 if (Atomic::cmpxchg(&_head, old_head, new_head) == old_head) { 1650 // successfully push 1651 new_head->_next = (HeapDumpLargeObjectListElem*)old_head; 1652 return; 1653 } 1654 } 1655 } 1656 1657 oop pop() { 1658 if (_head == nullptr) { 1659 return nullptr; 1660 } 1661 HeapDumpLargeObjectListElem* entry = (HeapDumpLargeObjectListElem*)_head; 1662 _head = _head->_next; 1663 assert (entry != nullptr, "illegal larger object list entry"); 1664 oop ret = entry->_obj; 1665 delete entry; 1666 assert (ret != nullptr, "illegal oop pointer"); 1667 return ret; 1668 } 1669 1670 void drain(ObjectClosure* cl) { 1671 while (_head != nullptr) { 1672 cl->do_object(pop()); 1673 } 1674 } 1675 1676 bool is_empty() { 1677 return _head == nullptr; 1678 } 1679 1680 static const size_t LargeObjectSizeThreshold = 1 << 20; // 1 MB 1681 }; 1682 1683 class VM_HeapDumper; 1684 1685 // Support class using when iterating over the heap. 1686 class HeapObjectDumper : public ObjectClosure { 1687 private: 1688 AbstractDumpWriter* _writer; 1689 HeapDumpLargeObjectList* _list; 1690 1691 AbstractDumpWriter* writer() { return _writer; } 1692 bool is_large(oop o); 1693 public: 1694 HeapObjectDumper(AbstractDumpWriter* writer, HeapDumpLargeObjectList* list = nullptr) { 1695 _writer = writer; 1696 _list = list; 1697 } 1698 1699 // called for each object in the heap 1700 void do_object(oop o); 1701 }; 1702 1703 void HeapObjectDumper::do_object(oop o) { 1704 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records 1705 if (o->klass() == vmClasses::Class_klass()) { 1706 if (!java_lang_Class::is_primitive(o)) { 1707 return; 1708 } 1709 } 1710 1711 if (DumperSupport::mask_dormant_archived_object(o) == nullptr) { 1712 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o), o->klass()->external_name()); 1713 return; 1714 } 1715 1716 // If large object list exists and it is large object/array, 1717 // add oop into the list and skip scan. VM thread will process it later. 1718 if (_list != nullptr && is_large(o)) { 1719 _list->atomic_push(o); 1720 return; 1721 } 1722 1723 if (o->is_instance()) { 1724 // create a HPROF_GC_INSTANCE record for each object 1725 DumperSupport::dump_instance(writer(), o); 1726 } else if (o->is_objArray()) { 1727 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array 1728 DumperSupport::dump_object_array(writer(), objArrayOop(o)); 1729 } else if (o->is_typeArray()) { 1730 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array 1731 DumperSupport::dump_prim_array(writer(), typeArrayOop(o)); 1732 } 1733 } 1734 1735 bool HeapObjectDumper::is_large(oop o) { 1736 size_t size = 0; 1737 if (o->is_instance()) { 1738 // Use o->size() * 8 as the upper limit of instance size to avoid iterating static fields 1739 size = o->size() * 8; 1740 } else if (o->is_objArray()) { 1741 objArrayOop array = objArrayOop(o); 1742 BasicType type = ArrayKlass::cast(array->klass())->element_type(); 1743 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type"); 1744 int length = array->length(); 1745 int type_size = sizeof(address); 1746 size = (size_t)length * type_size; 1747 } else if (o->is_typeArray()) { 1748 typeArrayOop array = typeArrayOop(o); 1749 BasicType type = ArrayKlass::cast(array->klass())->element_type(); 1750 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type"); 1751 int length = array->length(); 1752 int type_size = type2aelembytes(type); 1753 size = (size_t)length * type_size; 1754 } 1755 return size > HeapDumpLargeObjectList::LargeObjectSizeThreshold; 1756 } 1757 1758 // The dumper controller for parallel heap dump 1759 class DumperController : public CHeapObj<mtInternal> { 1760 private: 1761 bool _started; 1762 Monitor* _lock; 1763 uint _dumper_number; 1764 uint _complete_number; 1765 1766 public: 1767 DumperController(uint number) : 1768 _started(false), 1769 _lock(new (std::nothrow) PaddedMonitor(Mutex::safepoint, "DumperController_lock")), 1770 _dumper_number(number), 1771 _complete_number(0) { } 1772 1773 ~DumperController() { delete _lock; } 1774 1775 void wait_for_start_signal() { 1776 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag); 1777 while (_started == false) { 1778 ml.wait(); 1779 } 1780 assert(_started == true, "dumper woke up with wrong state"); 1781 } 1782 1783 void start_dump() { 1784 assert (_started == false, "start dump with wrong state"); 1785 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag); 1786 _started = true; 1787 ml.notify_all(); 1788 } 1789 1790 void dumper_complete() { 1791 assert (_started == true, "dumper complete with wrong state"); 1792 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag); 1793 _complete_number++; 1794 ml.notify(); 1795 } 1796 1797 void wait_all_dumpers_complete() { 1798 assert (_started == true, "wrong state when wait for dumper complete"); 1799 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag); 1800 while (_complete_number != _dumper_number) { 1801 ml.wait(); 1802 } 1803 _started = false; 1804 } 1805 }; 1806 1807 // The VM operation that performs the heap dump 1808 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask { 1809 private: 1810 static VM_HeapDumper* _global_dumper; 1811 static DumpWriter* _global_writer; 1812 DumpWriter* _local_writer; 1813 JavaThread* _oome_thread; 1814 Method* _oome_constructor; 1815 bool _gc_before_heap_dump; 1816 GrowableArray<Klass*>* _klass_map; 1817 ThreadStackTrace** _stack_traces; 1818 int _num_threads; 1819 // parallel heap dump support 1820 uint _num_dumper_threads; 1821 uint _num_writer_threads; 1822 DumperController* _dumper_controller; 1823 ParallelObjectIterator* _poi; 1824 HeapDumpLargeObjectList* _large_object_list; 1825 1826 // VMDumperType is for thread that dumps both heap and non-heap data. 1827 static const size_t VMDumperType = 0; 1828 static const size_t WriterType = 1; 1829 static const size_t DumperType = 2; 1830 // worker id of VMDumper thread. 1831 static const size_t VMDumperWorkerId = 0; 1832 1833 size_t get_worker_type(uint worker_id) { 1834 assert(_num_writer_threads >= 1, "Must be at least one writer"); 1835 // worker id of VMDumper that dump heap and non-heap data 1836 if (worker_id == VMDumperWorkerId) { 1837 return VMDumperType; 1838 } 1839 1840 // worker id of dumper starts from 1, which only dump heap datar 1841 if (worker_id < _num_dumper_threads) { 1842 return DumperType; 1843 } 1844 1845 // worker id of writer starts from _num_dumper_threads 1846 return WriterType; 1847 } 1848 1849 void prepare_parallel_dump(uint num_total) { 1850 assert (_dumper_controller == nullptr, "dumper controller must be null"); 1851 assert (num_total > 0, "active workers number must >= 1"); 1852 // Dumper threads number must not be larger than active workers number. 1853 if (num_total < _num_dumper_threads) { 1854 _num_dumper_threads = num_total - 1; 1855 } 1856 // Calculate dumper and writer threads number. 1857 _num_writer_threads = num_total - _num_dumper_threads; 1858 // If dumper threads number is 1, only the VMThread works as a dumper. 1859 // If dumper threads number is equal to active workers, need at lest one worker thread as writer. 1860 if (_num_dumper_threads > 0 && _num_writer_threads == 0) { 1861 _num_writer_threads = 1; 1862 _num_dumper_threads = num_total - _num_writer_threads; 1863 } 1864 // Prepare parallel writer. 1865 if (_num_dumper_threads > 1) { 1866 ParDumpWriter::before_work(); 1867 // Number of dumper threads that only iterate heap. 1868 uint _heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */; 1869 _dumper_controller = new (std::nothrow) DumperController(_heap_only_dumper_threads); 1870 } 1871 } 1872 1873 void finish_parallel_dump() { 1874 if (_num_dumper_threads > 1) { 1875 ParDumpWriter::after_work(); 1876 } 1877 } 1878 1879 // accessors and setters 1880 static VM_HeapDumper* dumper() { assert(_global_dumper != nullptr, "Error"); return _global_dumper; } 1881 static DumpWriter* writer() { assert(_global_writer != nullptr, "Error"); return _global_writer; } 1882 void set_global_dumper() { 1883 assert(_global_dumper == nullptr, "Error"); 1884 _global_dumper = this; 1885 } 1886 void set_global_writer() { 1887 assert(_global_writer == nullptr, "Error"); 1888 _global_writer = _local_writer; 1889 } 1890 void clear_global_dumper() { _global_dumper = nullptr; } 1891 void clear_global_writer() { _global_writer = nullptr; } 1892 1893 bool skip_operation() const; 1894 1895 // writes a HPROF_LOAD_CLASS record 1896 static void do_load_class(Klass* k); 1897 1898 // writes a HPROF_GC_CLASS_DUMP record for the given class 1899 static void do_class_dump(Klass* k); 1900 1901 // HPROF_GC_ROOT_THREAD_OBJ records 1902 int do_thread(JavaThread* thread, u4 thread_serial_num); 1903 void do_threads(); 1904 1905 void add_class_serial_number(Klass* k, int serial_num) { 1906 _klass_map->at_put_grow(serial_num, k); 1907 } 1908 1909 // HPROF_TRACE and HPROF_FRAME records 1910 void dump_stack_traces(); 1911 1912 // large objects 1913 void dump_large_objects(ObjectClosure* writer); 1914 1915 public: 1916 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) : 1917 VM_GC_Operation(0 /* total collections, dummy, ignored */, 1918 GCCause::_heap_dump /* GC Cause */, 1919 0 /* total full collections, dummy, ignored */, 1920 gc_before_heap_dump), 1921 WorkerTask("dump heap") { 1922 _local_writer = writer; 1923 _gc_before_heap_dump = gc_before_heap_dump; 1924 _klass_map = new (mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability); 1925 _stack_traces = nullptr; 1926 _num_threads = 0; 1927 _num_dumper_threads = num_dump_threads; 1928 _dumper_controller = nullptr; 1929 _poi = nullptr; 1930 _large_object_list = new (std::nothrow) HeapDumpLargeObjectList(); 1931 if (oome) { 1932 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread"); 1933 // get OutOfMemoryError zero-parameter constructor 1934 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass(); 1935 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(), 1936 vmSymbols::void_method_signature()); 1937 // get thread throwing OOME when generating the heap dump at OOME 1938 _oome_thread = JavaThread::current(); 1939 } else { 1940 _oome_thread = nullptr; 1941 _oome_constructor = nullptr; 1942 } 1943 } 1944 1945 ~VM_HeapDumper() { 1946 if (_stack_traces != nullptr) { 1947 for (int i=0; i < _num_threads; i++) { 1948 delete _stack_traces[i]; 1949 } 1950 FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces); 1951 } 1952 if (_dumper_controller != nullptr) { 1953 delete _dumper_controller; 1954 _dumper_controller = nullptr; 1955 } 1956 delete _klass_map; 1957 delete _large_object_list; 1958 } 1959 1960 VMOp_Type type() const { return VMOp_HeapDumper; } 1961 virtual bool doit_prologue(); 1962 void doit(); 1963 void work(uint worker_id); 1964 }; 1965 1966 VM_HeapDumper* VM_HeapDumper::_global_dumper = nullptr; 1967 DumpWriter* VM_HeapDumper::_global_writer = nullptr; 1968 1969 bool VM_HeapDumper::skip_operation() const { 1970 return false; 1971 } 1972 1973 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record 1974 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) { 1975 writer->finish_dump_segment(); 1976 1977 writer->write_u1(HPROF_HEAP_DUMP_END); 1978 writer->write_u4(0); 1979 writer->write_u4(0); 1980 } 1981 1982 // writes a HPROF_LOAD_CLASS record for the class 1983 void VM_HeapDumper::do_load_class(Klass* k) { 1984 static u4 class_serial_num = 0; 1985 1986 // len of HPROF_LOAD_CLASS record 1987 u4 remaining = 2*oopSize + 2*sizeof(u4); 1988 1989 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining); 1990 1991 // class serial number is just a number 1992 writer()->write_u4(++class_serial_num); 1993 1994 // class ID 1995 writer()->write_classID(k); 1996 1997 // add the Klass* and class serial number pair 1998 dumper()->add_class_serial_number(k, class_serial_num); 1999 2000 writer()->write_u4(STACK_TRACE_ID); 2001 2002 // class name ID 2003 Symbol* name = k->name(); 2004 writer()->write_symbolID(name); 2005 } 2006 2007 // writes a HPROF_GC_CLASS_DUMP record for the given class 2008 void VM_HeapDumper::do_class_dump(Klass* k) { 2009 if (k->is_instance_klass()) { 2010 DumperSupport::dump_instance_class(writer(), k); 2011 } else { 2012 DumperSupport::dump_array_class(writer(), k); 2013 } 2014 } 2015 2016 // Walk the stack of the given thread. 2017 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local 2018 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local 2019 // 2020 // It returns the number of Java frames in this thread stack 2021 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) { 2022 JNILocalsDumper blk(writer(), thread_serial_num); 2023 2024 oop threadObj = java_thread->threadObj(); 2025 assert(threadObj != nullptr, "sanity check"); 2026 2027 int stack_depth = 0; 2028 if (java_thread->has_last_Java_frame()) { 2029 2030 // vframes are resource allocated 2031 Thread* current_thread = Thread::current(); 2032 ResourceMark rm(current_thread); 2033 HandleMark hm(current_thread); 2034 2035 RegisterMap reg_map(java_thread, 2036 RegisterMap::UpdateMap::include, 2037 RegisterMap::ProcessFrames::include, 2038 RegisterMap::WalkContinuation::skip); 2039 frame f = java_thread->last_frame(); 2040 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread); 2041 frame* last_entry_frame = nullptr; 2042 int extra_frames = 0; 2043 2044 if (java_thread == _oome_thread && _oome_constructor != nullptr) { 2045 extra_frames++; 2046 } 2047 while (vf != nullptr) { 2048 blk.set_frame_number(stack_depth); 2049 if (vf->is_java_frame()) { 2050 2051 // java frame (interpreted, compiled, ...) 2052 javaVFrame *jvf = javaVFrame::cast(vf); 2053 if (!(jvf->method()->is_native())) { 2054 StackValueCollection* locals = jvf->locals(); 2055 for (int slot=0; slot<locals->size(); slot++) { 2056 if (locals->at(slot)->type() == T_OBJECT) { 2057 oop o = locals->obj_at(slot)(); 2058 2059 if (o != nullptr) { 2060 u4 size = 1 + sizeof(address) + 4 + 4; 2061 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size); 2062 writer()->write_objectID(o); 2063 writer()->write_u4(thread_serial_num); 2064 writer()->write_u4((u4) (stack_depth + extra_frames)); 2065 writer()->end_sub_record(); 2066 } 2067 } 2068 } 2069 StackValueCollection *exprs = jvf->expressions(); 2070 for(int index = 0; index < exprs->size(); index++) { 2071 if (exprs->at(index)->type() == T_OBJECT) { 2072 oop o = exprs->obj_at(index)(); 2073 if (o != nullptr) { 2074 u4 size = 1 + sizeof(address) + 4 + 4; 2075 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size); 2076 writer()->write_objectID(o); 2077 writer()->write_u4(thread_serial_num); 2078 writer()->write_u4((u4) (stack_depth + extra_frames)); 2079 writer()->end_sub_record(); 2080 } 2081 } 2082 } 2083 } else { 2084 // native frame 2085 if (stack_depth == 0) { 2086 // JNI locals for the top frame. 2087 java_thread->active_handles()->oops_do(&blk); 2088 } else { 2089 if (last_entry_frame != nullptr) { 2090 // JNI locals for the entry frame 2091 assert(last_entry_frame->is_entry_frame(), "checking"); 2092 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk); 2093 } 2094 } 2095 } 2096 // increment only for Java frames 2097 stack_depth++; 2098 last_entry_frame = nullptr; 2099 2100 } else { 2101 // externalVFrame - if it's an entry frame then report any JNI locals 2102 // as roots when we find the corresponding native javaVFrame 2103 frame* fr = vf->frame_pointer(); 2104 assert(fr != nullptr, "sanity check"); 2105 if (fr->is_entry_frame()) { 2106 last_entry_frame = fr; 2107 } 2108 } 2109 vf = vf->sender(); 2110 } 2111 } else { 2112 // no last java frame but there may be JNI locals 2113 java_thread->active_handles()->oops_do(&blk); 2114 } 2115 return stack_depth; 2116 } 2117 2118 2119 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk 2120 // the stack so that locals and JNI locals are dumped. 2121 void VM_HeapDumper::do_threads() { 2122 for (int i=0; i < _num_threads; i++) { 2123 JavaThread* thread = _stack_traces[i]->thread(); 2124 oop threadObj = thread->threadObj(); 2125 u4 thread_serial_num = i+1; 2126 u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID; 2127 u4 size = 1 + sizeof(address) + 4 + 4; 2128 writer()->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size); 2129 writer()->write_objectID(threadObj); 2130 writer()->write_u4(thread_serial_num); // thread number 2131 writer()->write_u4(stack_serial_num); // stack trace serial number 2132 writer()->end_sub_record(); 2133 int num_frames = do_thread(thread, thread_serial_num); 2134 assert(num_frames == _stack_traces[i]->get_stack_depth(), 2135 "total number of Java frames not matched"); 2136 } 2137 } 2138 2139 bool VM_HeapDumper::doit_prologue() { 2140 if (_gc_before_heap_dump && UseZGC) { 2141 // ZGC cannot perform a synchronous GC cycle from within the VM thread. 2142 // So ZCollectedHeap::collect_as_vm_thread() is a noop. To respect the 2143 // _gc_before_heap_dump flag a synchronous GC cycle is performed from 2144 // the caller thread in the prologue. 2145 Universe::heap()->collect(GCCause::_heap_dump); 2146 } 2147 return VM_GC_Operation::doit_prologue(); 2148 } 2149 2150 2151 // The VM operation that dumps the heap. The dump consists of the following 2152 // records: 2153 // 2154 // HPROF_HEADER 2155 // [HPROF_UTF8]* 2156 // [HPROF_LOAD_CLASS]* 2157 // [[HPROF_FRAME]*|HPROF_TRACE]* 2158 // [HPROF_GC_CLASS_DUMP]* 2159 // [HPROF_HEAP_DUMP_SEGMENT]* 2160 // HPROF_HEAP_DUMP_END 2161 // 2162 // The HPROF_TRACE records represent the stack traces where the heap dump 2163 // is generated and a "dummy trace" record which does not include 2164 // any frames. The dummy trace record is used to be referenced as the 2165 // unknown object alloc site. 2166 // 2167 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records. 2168 // To allow the heap dump be generated in a single pass we remember the position 2169 // of the dump length and fix it up after all sub-records have been written. 2170 // To generate the sub-records we iterate over the heap, writing 2171 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP 2172 // records as we go. Once that is done we write records for some of the GC 2173 // roots. 2174 2175 void VM_HeapDumper::doit() { 2176 2177 CollectedHeap* ch = Universe::heap(); 2178 2179 ch->ensure_parsability(false); // must happen, even if collection does 2180 // not happen (e.g. due to GCLocker) 2181 2182 if (_gc_before_heap_dump) { 2183 if (GCLocker::is_active()) { 2184 warning("GC locker is held; pre-heapdump GC was skipped"); 2185 } else { 2186 ch->collect_as_vm_thread(GCCause::_heap_dump); 2187 } 2188 } 2189 2190 // At this point we should be the only dumper active, so 2191 // the following should be safe. 2192 set_global_dumper(); 2193 set_global_writer(); 2194 2195 WorkerThreads* workers = ch->safepoint_workers(); 2196 2197 if (workers == nullptr) { 2198 // Use serial dump, set dumper threads and writer threads number to 1. 2199 _num_dumper_threads=1; 2200 _num_writer_threads=1; 2201 work(0); 2202 } else { 2203 prepare_parallel_dump(workers->active_workers()); 2204 if (_num_dumper_threads > 1) { 2205 ParallelObjectIterator poi(_num_dumper_threads); 2206 _poi = &poi; 2207 workers->run_task(this); 2208 _poi = nullptr; 2209 } else { 2210 workers->run_task(this); 2211 } 2212 finish_parallel_dump(); 2213 } 2214 2215 // Now we clear the global variables, so that a future dumper can run. 2216 clear_global_dumper(); 2217 clear_global_writer(); 2218 } 2219 2220 void VM_HeapDumper::work(uint worker_id) { 2221 if (worker_id != 0) { 2222 if (get_worker_type(worker_id) == WriterType) { 2223 writer()->writer_loop(); 2224 return; 2225 } 2226 if (_num_dumper_threads > 1 && get_worker_type(worker_id) == DumperType) { 2227 _dumper_controller->wait_for_start_signal(); 2228 } 2229 } else { 2230 // The worker 0 on all non-heap data dumping and part of heap iteration. 2231 // Write the file header - we always use 1.0.2 2232 const char* header = "JAVA PROFILE 1.0.2"; 2233 2234 // header is few bytes long - no chance to overflow int 2235 writer()->write_raw(header, strlen(header) + 1); // NUL terminated 2236 writer()->write_u4(oopSize); 2237 // timestamp is current time in ms 2238 writer()->write_u8(os::javaTimeMillis()); 2239 // HPROF_UTF8 records 2240 SymbolTableDumper sym_dumper(writer()); 2241 SymbolTable::symbols_do(&sym_dumper); 2242 2243 // write HPROF_LOAD_CLASS records 2244 { 2245 LockedClassesDo locked_load_classes(&do_load_class); 2246 ClassLoaderDataGraph::classes_do(&locked_load_classes); 2247 } 2248 2249 // write HPROF_FRAME and HPROF_TRACE records 2250 // this must be called after _klass_map is built when iterating the classes above. 2251 dump_stack_traces(); 2252 2253 // Writes HPROF_GC_CLASS_DUMP records 2254 { 2255 LockedClassesDo locked_dump_class(&do_class_dump); 2256 ClassLoaderDataGraph::classes_do(&locked_dump_class); 2257 } 2258 2259 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals 2260 do_threads(); 2261 2262 // HPROF_GC_ROOT_JNI_GLOBAL 2263 JNIGlobalsDumper jni_dumper(writer()); 2264 JNIHandles::oops_do(&jni_dumper); 2265 // technically not jni roots, but global roots 2266 // for things like preallocated throwable backtraces 2267 Universe::vm_global()->oops_do(&jni_dumper); 2268 // HPROF_GC_ROOT_STICKY_CLASS 2269 // These should be classes in the null class loader data, and not all classes 2270 // if !ClassUnloading 2271 StickyClassDumper class_dumper(writer()); 2272 ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper); 2273 } 2274 // writes HPROF_GC_INSTANCE_DUMP records. 2275 // After each sub-record is written check_segment_length will be invoked 2276 // to check if the current segment exceeds a threshold. If so, a new 2277 // segment is started. 2278 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk 2279 // of the heap dump. 2280 if (_num_dumper_threads <= 1) { 2281 HeapObjectDumper obj_dumper(writer()); 2282 Universe::heap()->object_iterate(&obj_dumper); 2283 } else { 2284 assert(get_worker_type(worker_id) == DumperType 2285 || get_worker_type(worker_id) == VMDumperType, 2286 "must be dumper thread to do heap iteration"); 2287 if (get_worker_type(worker_id) == VMDumperType) { 2288 // Clear global writer's buffer. 2289 writer()->finish_dump_segment(true); 2290 // Notify dumpers to start heap iteration. 2291 _dumper_controller->start_dump(); 2292 } 2293 // Heap iteration. 2294 { 2295 ParDumpWriter pw(writer()); 2296 { 2297 HeapObjectDumper obj_dumper(&pw, _large_object_list); 2298 _poi->object_iterate(&obj_dumper, worker_id); 2299 } 2300 2301 if (get_worker_type(worker_id) == VMDumperType) { 2302 _dumper_controller->wait_all_dumpers_complete(); 2303 // clear internal buffer; 2304 pw.finish_dump_segment(true); 2305 // refresh the global_writer's buffer and position; 2306 writer()->refresh(); 2307 } else { 2308 pw.finish_dump_segment(true); 2309 _dumper_controller->dumper_complete(); 2310 return; 2311 } 2312 } 2313 } 2314 2315 assert(get_worker_type(worker_id) == VMDumperType, "Heap dumper must be VMDumper"); 2316 // Use writer() rather than ParDumpWriter to avoid memory consumption. 2317 HeapObjectDumper obj_dumper(writer()); 2318 dump_large_objects(&obj_dumper); 2319 // Writes the HPROF_HEAP_DUMP_END record. 2320 DumperSupport::end_of_dump(writer()); 2321 // We are done with writing. Release the worker threads. 2322 writer()->deactivate(); 2323 } 2324 2325 void VM_HeapDumper::dump_stack_traces() { 2326 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites 2327 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4)); 2328 writer()->write_u4((u4) STACK_TRACE_ID); 2329 writer()->write_u4(0); // thread number 2330 writer()->write_u4(0); // frame count 2331 2332 _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal); 2333 int frame_serial_num = 0; 2334 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) { 2335 oop threadObj = thread->threadObj(); 2336 if (threadObj != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view()) { 2337 // dump thread stack trace 2338 Thread* current_thread = Thread::current(); 2339 ResourceMark rm(current_thread); 2340 HandleMark hm(current_thread); 2341 2342 ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false); 2343 stack_trace->dump_stack_at_safepoint(-1, /* ObjectMonitorsHashtable is not needed here */ nullptr, true); 2344 _stack_traces[_num_threads++] = stack_trace; 2345 2346 // write HPROF_FRAME records for this thread's stack trace 2347 int depth = stack_trace->get_stack_depth(); 2348 int thread_frame_start = frame_serial_num; 2349 int extra_frames = 0; 2350 // write fake frame that makes it look like the thread, which caused OOME, 2351 // is in the OutOfMemoryError zero-parameter constructor 2352 if (thread == _oome_thread && _oome_constructor != nullptr) { 2353 int oome_serial_num = _klass_map->find(_oome_constructor->method_holder()); 2354 // the class serial number starts from 1 2355 assert(oome_serial_num > 0, "OutOfMemoryError class not found"); 2356 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num, 2357 _oome_constructor, 0); 2358 extra_frames++; 2359 } 2360 for (int j=0; j < depth; j++) { 2361 StackFrameInfo* frame = stack_trace->stack_frame_at(j); 2362 Method* m = frame->method(); 2363 int class_serial_num = _klass_map->find(m->method_holder()); 2364 // the class serial number starts from 1 2365 assert(class_serial_num > 0, "class not found"); 2366 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci()); 2367 } 2368 depth += extra_frames; 2369 2370 // write HPROF_TRACE record for one thread 2371 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize); 2372 int stack_serial_num = _num_threads + STACK_TRACE_ID; 2373 writer()->write_u4(stack_serial_num); // stack trace serial number 2374 writer()->write_u4((u4) _num_threads); // thread serial number 2375 writer()->write_u4(depth); // frame count 2376 for (int j=1; j <= depth; j++) { 2377 writer()->write_id(thread_frame_start + j); 2378 } 2379 } 2380 } 2381 } 2382 2383 // dump the large objects. 2384 void VM_HeapDumper::dump_large_objects(ObjectClosure* cl) { 2385 _large_object_list->drain(cl); 2386 } 2387 2388 // dump the heap to given path. 2389 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) { 2390 assert(path != nullptr && strlen(path) > 0, "path missing"); 2391 2392 // print message in interactive case 2393 if (out != nullptr) { 2394 out->print_cr("Dumping heap to %s ...", path); 2395 timer()->start(); 2396 } 2397 // create JFR event 2398 EventHeapDump event; 2399 2400 AbstractCompressor* compressor = nullptr; 2401 2402 if (compression > 0) { 2403 compressor = new (std::nothrow) GZipCompressor(compression); 2404 2405 if (compressor == nullptr) { 2406 set_error("Could not allocate gzip compressor"); 2407 return -1; 2408 } 2409 } 2410 2411 DumpWriter writer(new (std::nothrow) FileWriter(path, overwrite), compressor); 2412 2413 if (writer.error() != nullptr) { 2414 set_error(writer.error()); 2415 if (out != nullptr) { 2416 out->print_cr("Unable to create %s: %s", path, 2417 (error() != nullptr) ? error() : "reason unknown"); 2418 } 2419 return -1; 2420 } 2421 2422 // generate the dump 2423 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads); 2424 if (Thread::current()->is_VM_thread()) { 2425 assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint"); 2426 dumper.doit(); 2427 } else { 2428 VMThread::execute(&dumper); 2429 } 2430 2431 // record any error that the writer may have encountered 2432 set_error(writer.error()); 2433 2434 // emit JFR event 2435 if (error() == nullptr) { 2436 event.set_destination(path); 2437 event.set_gcBeforeDump(_gc_before_heap_dump); 2438 event.set_size(writer.bytes_written()); 2439 event.set_onOutOfMemoryError(_oome); 2440 event.set_overwrite(overwrite); 2441 event.set_compression(compression); 2442 event.commit(); 2443 } else { 2444 log_debug(cds, heap)("Error %s while dumping heap", error()); 2445 } 2446 2447 // print message in interactive case 2448 if (out != nullptr) { 2449 timer()->stop(); 2450 if (error() == nullptr) { 2451 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]", 2452 writer.bytes_written(), timer()->seconds()); 2453 } else { 2454 out->print_cr("Dump file is incomplete: %s", writer.error()); 2455 } 2456 } 2457 2458 return (writer.error() == nullptr) ? 0 : -1; 2459 } 2460 2461 // stop timer (if still active), and free any error string we might be holding 2462 HeapDumper::~HeapDumper() { 2463 if (timer()->is_active()) { 2464 timer()->stop(); 2465 } 2466 set_error(nullptr); 2467 } 2468 2469 2470 // returns the error string (resource allocated), or null 2471 char* HeapDumper::error_as_C_string() const { 2472 if (error() != nullptr) { 2473 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1); 2474 strcpy(str, error()); 2475 return str; 2476 } else { 2477 return nullptr; 2478 } 2479 } 2480 2481 // set the error string 2482 void HeapDumper::set_error(char const* error) { 2483 if (_error != nullptr) { 2484 os::free(_error); 2485 } 2486 if (error == nullptr) { 2487 _error = nullptr; 2488 } else { 2489 _error = os::strdup(error); 2490 assert(_error != nullptr, "allocation failure"); 2491 } 2492 } 2493 2494 // Called by out-of-memory error reporting by a single Java thread 2495 // outside of a JVM safepoint 2496 void HeapDumper::dump_heap_from_oome() { 2497 HeapDumper::dump_heap(true); 2498 } 2499 2500 // Called by error reporting by a single Java thread outside of a JVM safepoint, 2501 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various 2502 // callers are strictly serialized and guaranteed not to interfere below. For more 2503 // general use, however, this method will need modification to prevent 2504 // inteference when updating the static variables base_path and dump_file_seq below. 2505 void HeapDumper::dump_heap() { 2506 HeapDumper::dump_heap(false); 2507 } 2508 2509 void HeapDumper::dump_heap(bool oome) { 2510 static char base_path[JVM_MAXPATHLEN] = {'\0'}; 2511 static uint dump_file_seq = 0; 2512 char* my_path; 2513 const int max_digit_chars = 20; 2514 2515 const char* dump_file_name = "java_pid"; 2516 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof"; 2517 2518 // The dump file defaults to java_pid<pid>.hprof in the current working 2519 // directory. HeapDumpPath=<file> can be used to specify an alternative 2520 // dump file name or a directory where dump file is created. 2521 if (dump_file_seq == 0) { // first time in, we initialize base_path 2522 // Calculate potentially longest base path and check if we have enough 2523 // allocated statically. 2524 const size_t total_length = 2525 (HeapDumpPath == nullptr ? 0 : strlen(HeapDumpPath)) + 2526 strlen(os::file_separator()) + max_digit_chars + 2527 strlen(dump_file_name) + strlen(dump_file_ext) + 1; 2528 if (total_length > sizeof(base_path)) { 2529 warning("Cannot create heap dump file. HeapDumpPath is too long."); 2530 return; 2531 } 2532 2533 bool use_default_filename = true; 2534 if (HeapDumpPath == nullptr || HeapDumpPath[0] == '\0') { 2535 // HeapDumpPath=<file> not specified 2536 } else { 2537 strcpy(base_path, HeapDumpPath); 2538 // check if the path is a directory (must exist) 2539 DIR* dir = os::opendir(base_path); 2540 if (dir == nullptr) { 2541 use_default_filename = false; 2542 } else { 2543 // HeapDumpPath specified a directory. We append a file separator 2544 // (if needed). 2545 os::closedir(dir); 2546 size_t fs_len = strlen(os::file_separator()); 2547 if (strlen(base_path) >= fs_len) { 2548 char* end = base_path; 2549 end += (strlen(base_path) - fs_len); 2550 if (strcmp(end, os::file_separator()) != 0) { 2551 strcat(base_path, os::file_separator()); 2552 } 2553 } 2554 } 2555 } 2556 // If HeapDumpPath wasn't a file name then we append the default name 2557 if (use_default_filename) { 2558 const size_t dlen = strlen(base_path); // if heap dump dir specified 2559 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s", 2560 dump_file_name, os::current_process_id(), dump_file_ext); 2561 } 2562 const size_t len = strlen(base_path) + 1; 2563 my_path = (char*)os::malloc(len, mtInternal); 2564 if (my_path == nullptr) { 2565 warning("Cannot create heap dump file. Out of system memory."); 2566 return; 2567 } 2568 strncpy(my_path, base_path, len); 2569 } else { 2570 // Append a sequence number id for dumps following the first 2571 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0 2572 my_path = (char*)os::malloc(len, mtInternal); 2573 if (my_path == nullptr) { 2574 warning("Cannot create heap dump file. Out of system memory."); 2575 return; 2576 } 2577 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq); 2578 } 2579 dump_file_seq++; // increment seq number for next time we dump 2580 2581 HeapDumper dumper(false /* no GC before heap dump */, 2582 oome /* pass along out-of-memory-error flag */); 2583 dumper.dump(my_path, tty, HeapDumpGzipLevel); 2584 os::free(my_path); 2585 }