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