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/fieldStreams.inline.hpp"
41 #include "oops/klass.inline.hpp"
42 #include "oops/objArrayKlass.hpp"
43 #include "oops/objArrayOop.inline.hpp"
44 #include "oops/oop.inline.hpp"
45 #include "oops/typeArrayOop.inline.hpp"
46 #include "runtime/frame.inline.hpp"
47 #include "runtime/handles.inline.hpp"
48 #include "runtime/javaCalls.hpp"
49 #include "runtime/javaThread.inline.hpp"
50 #include "runtime/jniHandles.hpp"
51 #include "runtime/os.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 class DumperClassCacheTable;
887 class DumperClassCacheTableEntry;
888
889 // Support class with a collection of functions used when dumping the heap
890 class DumperSupport : AllStatic {
891 public:
892
893 // write a header of the given type
894 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
895
896 // returns hprof tag for the given type signature
897 static hprofTag sig2tag(Symbol* sig);
898 // returns hprof tag for the given basic type
899 static hprofTag type2tag(BasicType type);
900 // Returns the size of the data to write.
901 static u4 sig2size(Symbol* sig);
902
903 // returns the size of the instance of the given class
904 static u4 instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry = nullptr);
905
906 // dump a jfloat
907 static void dump_float(AbstractDumpWriter* writer, jfloat f);
908 // dump a jdouble
909 static void dump_double(AbstractDumpWriter* writer, jdouble d);
910 // dumps the raw value of the given field
911 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
912 // returns the size of the static fields; also counts the static fields
913 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
914 // dumps static fields of the given class
915 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
916 // dump the raw values of the instance fields of the given object
917 static void dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry);
918 // get the count of the instance fields for a given class
919 static u2 get_instance_fields_count(InstanceKlass* ik);
920 // dumps the definition of the instance fields for a given class
921 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
922 // creates HPROF_GC_INSTANCE_DUMP record for the given object
923 static void dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache);
924 // creates HPROF_GC_CLASS_DUMP record for the given instance class
925 static void dump_instance_class(AbstractDumpWriter* writer, Klass* k);
926 // creates HPROF_GC_CLASS_DUMP record for a given array class
927 static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
928
929 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
930 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
931 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
932 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
933 // create HPROF_FRAME record for the given method and bci
934 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
935
936 // check if we need to truncate an array
937 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
938
939 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
940 static void end_of_dump(AbstractDumpWriter* writer);
941
942 static oop mask_dormant_archived_object(oop o, oop ref_obj) {
943 if (o != nullptr && o->klass()->java_mirror_no_keepalive() == nullptr) {
944 // Ignore this object since the corresponding java mirror is not loaded.
945 // Might be a dormant archive object.
946 report_dormant_archived_object(o, ref_obj);
947 return nullptr;
948 } else {
949 return o;
950 }
951 }
952
953 static void report_dormant_archived_object(oop o, oop ref_obj) {
954 if (log_is_enabled(Trace, cds, heap)) {
955 ResourceMark rm;
956 if (ref_obj != nullptr) {
957 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
958 p2i(o), o->klass()->external_name(),
959 p2i(ref_obj), ref_obj->klass()->external_name());
960 } else {
961 log_trace(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)",
962 p2i(o), o->klass()->external_name());
963 }
964 }
965 }
966 };
967
968 // Hash table of klasses to the klass metadata. This should greatly improve the
969 // hash dumping performance. This hash table is supposed to be used by a single
970 // thread only.
971 //
972 class DumperClassCacheTableEntry : public CHeapObj<mtServiceability> {
973 friend class DumperClassCacheTable;
974 private:
975 GrowableArray<char> _sigs_start;
976 GrowableArray<int> _offsets;
977 u4 _instance_size;
978 int _entries;
979
980 public:
981 DumperClassCacheTableEntry() : _instance_size(0), _entries(0) {};
982
983 int field_count() { return _entries; }
984 char sig_start(int field_idx) { return _sigs_start.at(field_idx); }
985 int offset(int field_idx) { return _offsets.at(field_idx); }
986 u4 instance_size() { return _instance_size; }
987 };
988
989 class DumperClassCacheTable {
990 private:
991 // ResourceHashtable SIZE is specified at compile time so we
992 // use 1031 which is the first prime after 1024.
993 static constexpr size_t TABLE_SIZE = 1031;
994
995 // Maintain the cache for N classes. This limits memory footprint
996 // impact, regardless of how many classes we have in the dump.
997 // This also improves look up performance by keeping the statically
998 // sized table from overloading.
999 static constexpr int CACHE_TOP = 256;
1000
1001 typedef ResourceHashtable<InstanceKlass*, DumperClassCacheTableEntry*,
1002 TABLE_SIZE, AnyObj::C_HEAP, mtServiceability> PtrTable;
1003 PtrTable* _ptrs;
1004
1005 // Single-slot cache to handle the major case of objects of the same
1006 // class back-to-back, e.g. from T[].
1007 InstanceKlass* _last_ik;
1008 DumperClassCacheTableEntry* _last_entry;
1009
1010 void unlink_all(PtrTable* table) {
1011 class CleanupEntry: StackObj {
1012 public:
1013 bool do_entry(InstanceKlass*& key, DumperClassCacheTableEntry*& entry) {
1014 delete entry;
1015 return true;
1016 }
1017 } cleanup;
1018 table->unlink(&cleanup);
1019 }
1020
1021 public:
1022 DumperClassCacheTableEntry* lookup_or_create(InstanceKlass* ik) {
1023 if (_last_ik == ik) {
1024 return _last_entry;
1025 }
1026
1027 DumperClassCacheTableEntry* entry;
1028 DumperClassCacheTableEntry** from_cache = _ptrs->get(ik);
1029 if (from_cache == nullptr) {
1030 entry = new DumperClassCacheTableEntry();
1031 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
1032 if (!fld.access_flags().is_static()) {
1033 Symbol* sig = fld.signature();
1034 entry->_sigs_start.push(sig->char_at(0));
1035 entry->_offsets.push(fld.offset());
1036 entry->_entries++;
1037 entry->_instance_size += DumperSupport::sig2size(sig);
1038 }
1039 }
1040
1041 if (_ptrs->number_of_entries() >= CACHE_TOP) {
1042 // We do not track the individual hit rates for table entries.
1043 // Purge the entire table, and let the cache catch up with new
1044 // distribution.
1045 unlink_all(_ptrs);
1046 }
1047
1048 _ptrs->put(ik, entry);
1049 } else {
1050 entry = *from_cache;
1051 }
1052
1053 // Remember for single-slot cache.
1054 _last_ik = ik;
1055 _last_entry = entry;
1056
1057 return entry;
1058 }
1059
1060 DumperClassCacheTable() : _ptrs(new (mtServiceability) PtrTable), _last_ik(nullptr), _last_entry(nullptr) {}
1061
1062 ~DumperClassCacheTable() {
1063 unlink_all(_ptrs);
1064 delete _ptrs;
1065 }
1066 };
1067
1068 // write a header of the given type
1069 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
1070 writer->write_u1(tag);
1071 writer->write_u4(0); // current ticks
1072 writer->write_u4(len);
1073 }
1074
1075 // returns hprof tag for the given type signature
1076 hprofTag DumperSupport::sig2tag(Symbol* sig) {
1077 switch (sig->char_at(0)) {
1078 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
1079 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
1080 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
1081 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
1082 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
1083 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
1084 case JVM_SIGNATURE_INT : return HPROF_INT;
1085 case JVM_SIGNATURE_LONG : return HPROF_LONG;
1086 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
1087 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
1088 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
1089 }
1090 }
1091
1092 hprofTag DumperSupport::type2tag(BasicType type) {
1093 switch (type) {
1094 case T_BYTE : return HPROF_BYTE;
1095 case T_CHAR : return HPROF_CHAR;
1096 case T_FLOAT : return HPROF_FLOAT;
1097 case T_DOUBLE : return HPROF_DOUBLE;
1098 case T_INT : return HPROF_INT;
1099 case T_LONG : return HPROF_LONG;
1100 case T_SHORT : return HPROF_SHORT;
1101 case T_BOOLEAN : return HPROF_BOOLEAN;
1102 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
1103 }
1104 }
1105
1106 u4 DumperSupport::sig2size(Symbol* sig) {
1107 switch (sig->char_at(0)) {
1108 case JVM_SIGNATURE_CLASS:
1109 case JVM_SIGNATURE_ARRAY: return sizeof(address);
1110 case JVM_SIGNATURE_BOOLEAN:
1111 case JVM_SIGNATURE_BYTE: return 1;
1112 case JVM_SIGNATURE_SHORT:
1113 case JVM_SIGNATURE_CHAR: return 2;
1114 case JVM_SIGNATURE_INT:
1115 case JVM_SIGNATURE_FLOAT: return 4;
1116 case JVM_SIGNATURE_LONG:
1117 case JVM_SIGNATURE_DOUBLE: return 8;
1118 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
1119 }
1120 }
1121
1122 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
1123 T to;
1124 static_assert(sizeof(to) == sizeof(from), "must be of the same size");
1125 memcpy(&to, &from, sizeof(to));
1126 return to;
1127 }
1128
1129 // dump a jfloat
1130 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
1131 if (g_isnan(f)) {
1132 writer->write_u4(0x7fc00000); // collapsing NaNs
1133 } else {
1134 writer->write_u4(bit_cast<u4>(f));
1135 }
1136 }
1137
1138 // dump a jdouble
1139 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
1140 if (g_isnan(d)) {
1141 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
1142 } else {
1143 writer->write_u8(bit_cast<u8>(d));
1144 }
1145 }
1146
1147 // dumps the raw value of the given field
1148 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
1149 switch (type) {
1150 case JVM_SIGNATURE_CLASS :
1151 case JVM_SIGNATURE_ARRAY : {
1152 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
1153 o = mask_dormant_archived_object(o, obj);
1154 assert(oopDesc::is_oop_or_null(o), "Expected an oop or nullptr at " PTR_FORMAT, p2i(o));
1155 writer->write_objectID(o);
1156 break;
1157 }
1158 case JVM_SIGNATURE_BYTE : {
1159 jbyte b = obj->byte_field(offset);
1160 writer->write_u1(b);
1161 break;
1162 }
1163 case JVM_SIGNATURE_CHAR : {
1164 jchar c = obj->char_field(offset);
1165 writer->write_u2(c);
1166 break;
1167 }
1168 case JVM_SIGNATURE_SHORT : {
1169 jshort s = obj->short_field(offset);
1170 writer->write_u2(s);
1171 break;
1172 }
1173 case JVM_SIGNATURE_FLOAT : {
1174 jfloat f = obj->float_field(offset);
1175 dump_float(writer, f);
1176 break;
1177 }
1178 case JVM_SIGNATURE_DOUBLE : {
1179 jdouble d = obj->double_field(offset);
1180 dump_double(writer, d);
1181 break;
1182 }
1183 case JVM_SIGNATURE_INT : {
1184 jint i = obj->int_field(offset);
1185 writer->write_u4(i);
1186 break;
1187 }
1188 case JVM_SIGNATURE_LONG : {
1189 jlong l = obj->long_field(offset);
1190 writer->write_u8(l);
1191 break;
1192 }
1193 case JVM_SIGNATURE_BOOLEAN : {
1194 jboolean b = obj->bool_field(offset);
1195 writer->write_u1(b);
1196 break;
1197 }
1198 default : {
1199 ShouldNotReachHere();
1200 break;
1201 }
1202 }
1203 }
1204
1205 // returns the size of the instance of the given class
1206 u4 DumperSupport::instance_size(InstanceKlass* ik, DumperClassCacheTableEntry* class_cache_entry) {
1207 if (class_cache_entry != nullptr) {
1208 return class_cache_entry->instance_size();
1209 } else {
1210 u4 size = 0;
1211 for (HierarchicalFieldStream<JavaFieldStream> fld(ik); !fld.done(); fld.next()) {
1212 if (!fld.access_flags().is_static()) {
1213 size += sig2size(fld.signature());
1214 }
1215 }
1216 return size;
1217 }
1218 }
1219
1220 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1221 field_count = 0;
1222 u4 size = 0;
1223
1224 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1225 if (fldc.access_flags().is_static()) {
1226 field_count++;
1227 size += sig2size(fldc.signature());
1228 }
1229 }
1230
1231 // Add in resolved_references which is referenced by the cpCache
1232 // The resolved_references is an array per InstanceKlass holding the
1233 // strings and other oops resolved from the constant pool.
1234 oop resolved_references = ik->constants()->resolved_references_or_null();
1235 if (resolved_references != nullptr) {
1236 field_count++;
1237 size += sizeof(address);
1238
1239 // Add in the resolved_references of the used previous versions of the class
1240 // in the case of RedefineClasses
1241 InstanceKlass* prev = ik->previous_versions();
1242 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1243 field_count++;
1244 size += sizeof(address);
1245 prev = prev->previous_versions();
1246 }
1247 }
1248
1249 // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
1250 // arrays.
1251 oop init_lock = ik->init_lock();
1252 if (init_lock != nullptr) {
1253 field_count++;
1254 size += sizeof(address);
1255 }
1256
1257 // We write the value itself plus a name and a one byte type tag per field.
1258 return size + field_count * (sizeof(address) + 1);
1259 }
1260
1261 // dumps static fields of the given class
1262 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1263 InstanceKlass* ik = InstanceKlass::cast(k);
1264
1265 // dump the field descriptors and raw values
1266 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1267 if (fld.access_flags().is_static()) {
1268 Symbol* sig = fld.signature();
1269
1270 writer->write_symbolID(fld.name()); // name
1271 writer->write_u1(sig2tag(sig)); // type
1272
1273 // value
1274 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1275 }
1276 }
1277
1278 // Add resolved_references for each class that has them
1279 oop resolved_references = ik->constants()->resolved_references_or_null();
1280 if (resolved_references != nullptr) {
1281 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1282 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1283 writer->write_objectID(resolved_references);
1284
1285 // Also write any previous versions
1286 InstanceKlass* prev = ik->previous_versions();
1287 while (prev != nullptr && prev->constants()->resolved_references_or_null() != nullptr) {
1288 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1289 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1290 writer->write_objectID(prev->constants()->resolved_references());
1291 prev = prev->previous_versions();
1292 }
1293 }
1294
1295 // Add init lock to the end if the class is not yet initialized
1296 oop init_lock = ik->init_lock();
1297 if (init_lock != nullptr) {
1298 writer->write_symbolID(vmSymbols::init_lock_name()); // name
1299 writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
1300 writer->write_objectID(init_lock);
1301 }
1302 }
1303
1304 // dump the raw values of the instance fields of the given object
1305 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o, DumperClassCacheTableEntry* class_cache_entry) {
1306 assert(class_cache_entry != nullptr, "Pre-condition: must be provided");
1307 for (int idx = 0; idx < class_cache_entry->field_count(); idx++) {
1308 dump_field_value(writer, class_cache_entry->sig_start(idx), o, class_cache_entry->offset(idx));
1309 }
1310 }
1311
1312 // dumps the definition of the instance fields for a given class
1313 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1314 u2 field_count = 0;
1315
1316 for (JavaFieldStream fldc(ik); !fldc.done(); fldc.next()) {
1317 if (!fldc.access_flags().is_static()) field_count++;
1318 }
1319
1320 return field_count;
1321 }
1322
1323 // dumps the definition of the instance fields for a given class
1324 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1325 InstanceKlass* ik = InstanceKlass::cast(k);
1326
1327 // dump the field descriptors
1328 for (JavaFieldStream fld(ik); !fld.done(); fld.next()) {
1329 if (!fld.access_flags().is_static()) {
1330 Symbol* sig = fld.signature();
1331
1332 writer->write_symbolID(fld.name()); // name
1333 writer->write_u1(sig2tag(sig)); // type
1334 }
1335 }
1336 }
1337
1338 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1339 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o, DumperClassCacheTable* class_cache) {
1340 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1341
1342 DumperClassCacheTableEntry* cache_entry = class_cache->lookup_or_create(ik);
1343
1344 u4 is = instance_size(ik, cache_entry);
1345 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1346
1347 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1348 writer->write_objectID(o);
1349 writer->write_u4(STACK_TRACE_ID);
1350
1351 // class ID
1352 writer->write_classID(ik);
1353
1354 // number of bytes that follow
1355 writer->write_u4(is);
1356
1357 // field values
1358 dump_instance_fields(writer, o, cache_entry);
1359
1360 writer->end_sub_record();
1361 }
1362
1363 // creates HPROF_GC_CLASS_DUMP record for the given instance class
1364 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) {
1365 InstanceKlass* ik = InstanceKlass::cast(k);
1366
1367 // We can safepoint and do a heap dump at a point where we have a Klass,
1368 // but no java mirror class has been setup for it. So we need to check
1369 // that the class is at least loaded, to avoid crash from a null mirror.
1370 if (!ik->is_loaded()) {
1371 return;
1372 }
1373
1374 u2 static_fields_count = 0;
1375 u4 static_size = get_static_fields_size(ik, static_fields_count);
1376 u2 instance_fields_count = get_instance_fields_count(ik);
1377 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1378 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size;
1379
1380 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1381
1382 // class ID
1383 writer->write_classID(ik);
1384 writer->write_u4(STACK_TRACE_ID);
1385
1386 // super class ID
1387 InstanceKlass* java_super = ik->java_super();
1388 if (java_super == nullptr) {
1389 writer->write_objectID(oop(nullptr));
1390 } else {
1391 writer->write_classID(java_super);
1392 }
1393
1394 writer->write_objectID(ik->class_loader());
1395 writer->write_objectID(ik->signers());
1396 writer->write_objectID(ik->protection_domain());
1397
1398 // reserved
1399 writer->write_objectID(oop(nullptr));
1400 writer->write_objectID(oop(nullptr));
1401
1402 // instance size
1403 writer->write_u4(DumperSupport::instance_size(ik));
1404
1405 // size of constant pool - ignored by HAT 1.1
1406 writer->write_u2(0);
1407
1408 // static fields
1409 writer->write_u2(static_fields_count);
1410 dump_static_fields(writer, ik);
1411
1412 // description of instance fields
1413 writer->write_u2(instance_fields_count);
1414 dump_instance_field_descriptors(writer, ik);
1415
1416 writer->end_sub_record();
1417 }
1418
1419 // creates HPROF_GC_CLASS_DUMP record for the given array class
1420 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
1421 InstanceKlass* ik = nullptr; // bottom class for object arrays, null for primitive type arrays
1422 if (k->is_objArray_klass()) {
1423 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
1424 assert(bk != nullptr, "checking");
1425 if (bk->is_instance_klass()) {
1426 ik = InstanceKlass::cast(bk);
1427 }
1428 }
1429
1430 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1431 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1432 writer->write_classID(k);
1433 writer->write_u4(STACK_TRACE_ID);
1434
1435 // super class of array classes is java.lang.Object
1436 InstanceKlass* java_super = k->java_super();
1437 assert(java_super != nullptr, "checking");
1438 writer->write_classID(java_super);
1439
1440 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->class_loader());
1441 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->signers());
1442 writer->write_objectID(ik == nullptr ? oop(nullptr) : ik->protection_domain());
1443
1444 writer->write_objectID(oop(nullptr)); // reserved
1445 writer->write_objectID(oop(nullptr));
1446 writer->write_u4(0); // instance size
1447 writer->write_u2(0); // constant pool
1448 writer->write_u2(0); // static fields
1449 writer->write_u2(0); // instance fields
1450
1451 writer->end_sub_record();
1452
1453 }
1454
1455 // Hprof uses an u4 as record length field,
1456 // which means we need to truncate arrays that are too long.
1457 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1458 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1459 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1460
1461 int length = array->length();
1462
1463 int type_size;
1464 if (type == T_OBJECT) {
1465 type_size = sizeof(address);
1466 } else {
1467 type_size = type2aelembytes(type);
1468 }
1469
1470 size_t length_in_bytes = (size_t)length * type_size;
1471 uint max_bytes = max_juint - header_size;
1472
1473 if (length_in_bytes > max_bytes) {
1474 length = max_bytes / type_size;
1475 length_in_bytes = (size_t)length * type_size;
1476
1477 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1478 type2name_tab[type], array->length(), length);
1479 }
1480 return length;
1481 }
1482
1483 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1484 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1485 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1486 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1487 int length = calculate_array_max_length(writer, array, header_size);
1488 u4 size = header_size + length * sizeof(address);
1489
1490 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1491 writer->write_objectID(array);
1492 writer->write_u4(STACK_TRACE_ID);
1493 writer->write_u4(length);
1494
1495 // array class ID
1496 writer->write_classID(array->klass());
1497
1498 // [id]* elements
1499 for (int index = 0; index < length; index++) {
1500 oop o = array->obj_at(index);
1501 o = mask_dormant_archived_object(o, array);
1502 writer->write_objectID(o);
1503 }
1504
1505 writer->end_sub_record();
1506 }
1507
1508 #define WRITE_ARRAY(Array, Type, Size, Length) \
1509 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1510
1511 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1512 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1513 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1514 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1515 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1516
1517 int length = calculate_array_max_length(writer, array, header_size);
1518 int type_size = type2aelembytes(type);
1519 u4 length_in_bytes = (u4)length * type_size;
1520 u4 size = header_size + length_in_bytes;
1521
1522 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1523 writer->write_objectID(array);
1524 writer->write_u4(STACK_TRACE_ID);
1525 writer->write_u4(length);
1526 writer->write_u1(type2tag(type));
1527
1528 // nothing to copy
1529 if (length == 0) {
1530 writer->end_sub_record();
1531 return;
1532 }
1533
1534 // If the byte ordering is big endian then we can copy most types directly
1535
1536 switch (type) {
1537 case T_INT : {
1538 if (Endian::is_Java_byte_ordering_different()) {
1539 WRITE_ARRAY(array, int, u4, length);
1540 } else {
1541 writer->write_raw(array->int_at_addr(0), length_in_bytes);
1542 }
1543 break;
1544 }
1545 case T_BYTE : {
1546 writer->write_raw(array->byte_at_addr(0), length_in_bytes);
1547 break;
1548 }
1549 case T_CHAR : {
1550 if (Endian::is_Java_byte_ordering_different()) {
1551 WRITE_ARRAY(array, char, u2, length);
1552 } else {
1553 writer->write_raw(array->char_at_addr(0), length_in_bytes);
1554 }
1555 break;
1556 }
1557 case T_SHORT : {
1558 if (Endian::is_Java_byte_ordering_different()) {
1559 WRITE_ARRAY(array, short, u2, length);
1560 } else {
1561 writer->write_raw(array->short_at_addr(0), length_in_bytes);
1562 }
1563 break;
1564 }
1565 case T_BOOLEAN : {
1566 if (Endian::is_Java_byte_ordering_different()) {
1567 WRITE_ARRAY(array, bool, u1, length);
1568 } else {
1569 writer->write_raw(array->bool_at_addr(0), length_in_bytes);
1570 }
1571 break;
1572 }
1573 case T_LONG : {
1574 if (Endian::is_Java_byte_ordering_different()) {
1575 WRITE_ARRAY(array, long, u8, length);
1576 } else {
1577 writer->write_raw(array->long_at_addr(0), length_in_bytes);
1578 }
1579 break;
1580 }
1581
1582 // handle float/doubles in a special value to ensure than NaNs are
1583 // written correctly. TO DO: Check if we can avoid this on processors that
1584 // use IEEE 754.
1585
1586 case T_FLOAT : {
1587 for (int i = 0; i < length; i++) {
1588 dump_float(writer, array->float_at(i));
1589 }
1590 break;
1591 }
1592 case T_DOUBLE : {
1593 for (int i = 0; i < length; i++) {
1594 dump_double(writer, array->double_at(i));
1595 }
1596 break;
1597 }
1598 default : ShouldNotReachHere();
1599 }
1600
1601 writer->end_sub_record();
1602 }
1603
1604 // create a HPROF_FRAME record of the given Method* and bci
1605 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1606 int frame_serial_num,
1607 int class_serial_num,
1608 Method* m,
1609 int bci) {
1610 int line_number;
1611 if (m->is_native()) {
1612 line_number = -3; // native frame
1613 } else {
1614 line_number = m->line_number_from_bci(bci);
1615 }
1616
1617 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1618 writer->write_id(frame_serial_num); // frame serial number
1619 writer->write_symbolID(m->name()); // method's name
1620 writer->write_symbolID(m->signature()); // method's signature
1621
1622 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1623 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1624 writer->write_u4(class_serial_num); // class serial number
1625 writer->write_u4((u4) line_number); // line number
1626 }
1627
1628
1629 // Support class used to generate HPROF_UTF8 records from the entries in the
1630 // SymbolTable.
1631
1632 class SymbolTableDumper : public SymbolClosure {
1633 private:
1634 AbstractDumpWriter* _writer;
1635 AbstractDumpWriter* writer() const { return _writer; }
1636 public:
1637 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1638 void do_symbol(Symbol** p);
1639 };
1640
1641 void SymbolTableDumper::do_symbol(Symbol** p) {
1642 ResourceMark rm;
1643 Symbol* sym = *p;
1644 int len = sym->utf8_length();
1645 if (len > 0) {
1646 char* s = sym->as_utf8();
1647 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1648 writer()->write_symbolID(sym);
1649 writer()->write_raw(s, len);
1650 }
1651 }
1652
1653 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1654
1655 class JNILocalsDumper : public OopClosure {
1656 private:
1657 AbstractDumpWriter* _writer;
1658 u4 _thread_serial_num;
1659 int _frame_num;
1660 AbstractDumpWriter* writer() const { return _writer; }
1661 public:
1662 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1663 _writer = writer;
1664 _thread_serial_num = thread_serial_num;
1665 _frame_num = -1; // default - empty stack
1666 }
1667 void set_frame_number(int n) { _frame_num = n; }
1668 void do_oop(oop* obj_p);
1669 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1670 };
1671
1672
1673 void JNILocalsDumper::do_oop(oop* obj_p) {
1674 // ignore null handles
1675 oop o = *obj_p;
1676 if (o != nullptr) {
1677 u4 size = 1 + sizeof(address) + 4 + 4;
1678 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1679 writer()->write_objectID(o);
1680 writer()->write_u4(_thread_serial_num);
1681 writer()->write_u4((u4)_frame_num);
1682 writer()->end_sub_record();
1683 }
1684 }
1685
1686
1687 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1688
1689 class JNIGlobalsDumper : public OopClosure {
1690 private:
1691 AbstractDumpWriter* _writer;
1692 AbstractDumpWriter* writer() const { return _writer; }
1693
1694 public:
1695 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1696 _writer = writer;
1697 }
1698 void do_oop(oop* obj_p);
1699 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1700 };
1701
1702 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1703 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1704
1705 // ignore these
1706 if (o == nullptr) return;
1707 // we ignore global ref to symbols and other internal objects
1708 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1709 u4 size = 1 + 2 * sizeof(address);
1710 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1711 writer()->write_objectID(o);
1712 writer()->write_rootID(obj_p); // global ref ID
1713 writer()->end_sub_record();
1714 }
1715 };
1716
1717 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1718
1719 class StickyClassDumper : public KlassClosure {
1720 private:
1721 AbstractDumpWriter* _writer;
1722 AbstractDumpWriter* writer() const { return _writer; }
1723 public:
1724 StickyClassDumper(AbstractDumpWriter* writer) {
1725 _writer = writer;
1726 }
1727 void do_klass(Klass* k) {
1728 if (k->is_instance_klass()) {
1729 InstanceKlass* ik = InstanceKlass::cast(k);
1730 u4 size = 1 + sizeof(address);
1731 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1732 writer()->write_classID(ik);
1733 writer()->end_sub_record();
1734 }
1735 }
1736 };
1737
1738 // Large object heap dump support.
1739 // To avoid memory consumption, when dumping large objects such as huge array and
1740 // large objects whose size are larger than LARGE_OBJECT_DUMP_THRESHOLD, the scanned
1741 // partial object/array data will be sent to the backend directly instead of caching
1742 // the whole object/array in the internal buffer.
1743 // The HeapDumpLargeObjectList is used to save the large object when dumper scans
1744 // the heap. The large objects could be added (push) parallelly by multiple dumpers,
1745 // But they will be removed (popped) serially only by the VM thread.
1746 class HeapDumpLargeObjectList : public CHeapObj<mtInternal> {
1747 private:
1748 class HeapDumpLargeObjectListElem : public CHeapObj<mtInternal> {
1749 public:
1750 HeapDumpLargeObjectListElem(oop obj) : _obj(obj), _next(nullptr) { }
1751 oop _obj;
1752 HeapDumpLargeObjectListElem* _next;
1753 };
1754
1755 volatile HeapDumpLargeObjectListElem* _head;
1756
1757 public:
1758 HeapDumpLargeObjectList() : _head(nullptr) { }
1759
1760 void atomic_push(oop obj) {
1761 assert (obj != nullptr, "sanity check");
1762 HeapDumpLargeObjectListElem* entry = new HeapDumpLargeObjectListElem(obj);
1763 if (entry == nullptr) {
1764 warning("failed to allocate element for large object list");
1765 return;
1766 }
1767 assert (entry->_obj != nullptr, "sanity check");
1768 while (true) {
1769 volatile HeapDumpLargeObjectListElem* old_head = Atomic::load_acquire(&_head);
1770 HeapDumpLargeObjectListElem* new_head = entry;
1771 if (Atomic::cmpxchg(&_head, old_head, new_head) == old_head) {
1772 // successfully push
1773 new_head->_next = (HeapDumpLargeObjectListElem*)old_head;
1774 return;
1775 }
1776 }
1777 }
1778
1779 oop pop() {
1780 if (_head == nullptr) {
1781 return nullptr;
1782 }
1783 HeapDumpLargeObjectListElem* entry = (HeapDumpLargeObjectListElem*)_head;
1784 _head = _head->_next;
1785 assert (entry != nullptr, "illegal larger object list entry");
1786 oop ret = entry->_obj;
1787 delete entry;
1788 assert (ret != nullptr, "illegal oop pointer");
1789 return ret;
1790 }
1791
1792 void drain(ObjectClosure* cl) {
1793 while (_head != nullptr) {
1794 cl->do_object(pop());
1795 }
1796 }
1797
1798 bool is_empty() {
1799 return _head == nullptr;
1800 }
1801
1802 static const size_t LargeObjectSizeThreshold = 1 << 20; // 1 MB
1803 };
1804
1805 class VM_HeapDumper;
1806
1807 // Support class using when iterating over the heap.
1808 class HeapObjectDumper : public ObjectClosure {
1809 private:
1810 AbstractDumpWriter* _writer;
1811 HeapDumpLargeObjectList* _list;
1812
1813 AbstractDumpWriter* writer() { return _writer; }
1814 bool is_large(oop o);
1815
1816 DumperClassCacheTable _class_cache;
1817
1818 public:
1819 HeapObjectDumper(AbstractDumpWriter* writer, HeapDumpLargeObjectList* list = nullptr) {
1820 _writer = writer;
1821 _list = list;
1822 }
1823
1824 // called for each object in the heap
1825 void do_object(oop o);
1826 };
1827
1828 void HeapObjectDumper::do_object(oop o) {
1829 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1830 if (o->klass() == vmClasses::Class_klass()) {
1831 if (!java_lang_Class::is_primitive(o)) {
1832 return;
1833 }
1834 }
1835
1836 if (DumperSupport::mask_dormant_archived_object(o, nullptr) == nullptr) {
1837 return;
1838 }
1839
1840 // If large object list exists and it is large object/array,
1841 // add oop into the list and skip scan. VM thread will process it later.
1842 if (_list != nullptr && is_large(o)) {
1843 _list->atomic_push(o);
1844 return;
1845 }
1846
1847 if (o->is_instance()) {
1848 // create a HPROF_GC_INSTANCE record for each object
1849 DumperSupport::dump_instance(writer(), o, &_class_cache);
1850 } else if (o->is_objArray()) {
1851 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1852 DumperSupport::dump_object_array(writer(), objArrayOop(o));
1853 } else if (o->is_typeArray()) {
1854 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1855 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1856 }
1857 }
1858
1859 bool HeapObjectDumper::is_large(oop o) {
1860 size_t size = 0;
1861 if (o->is_instance()) {
1862 // Use o->size() * 8 as the upper limit of instance size to avoid iterating static fields
1863 size = o->size() * 8;
1864 } else if (o->is_objArray()) {
1865 objArrayOop array = objArrayOop(o);
1866 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1867 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1868 int length = array->length();
1869 int type_size = sizeof(address);
1870 size = (size_t)length * type_size;
1871 } else if (o->is_typeArray()) {
1872 typeArrayOop array = typeArrayOop(o);
1873 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1874 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1875 int length = array->length();
1876 int type_size = type2aelembytes(type);
1877 size = (size_t)length * type_size;
1878 }
1879 return size > HeapDumpLargeObjectList::LargeObjectSizeThreshold;
1880 }
1881
1882 // The dumper controller for parallel heap dump
1883 class DumperController : public CHeapObj<mtInternal> {
1884 private:
1885 bool _started;
1886 Monitor* _lock;
1887 uint _dumper_number;
1888 uint _complete_number;
1889
1890 public:
1891 DumperController(uint number) :
1892 _started(false),
1893 _lock(new (std::nothrow) PaddedMonitor(Mutex::safepoint, "DumperController_lock")),
1894 _dumper_number(number),
1895 _complete_number(0) { }
1896
1897 ~DumperController() { delete _lock; }
1898
1899 void wait_for_start_signal() {
1900 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1901 while (_started == false) {
1902 ml.wait();
1903 }
1904 assert(_started == true, "dumper woke up with wrong state");
1905 }
1906
1907 void start_dump() {
1908 assert (_started == false, "start dump with wrong state");
1909 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1910 _started = true;
1911 ml.notify_all();
1912 }
1913
1914 void dumper_complete() {
1915 assert (_started == true, "dumper complete with wrong state");
1916 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1917 _complete_number++;
1918 ml.notify();
1919 }
1920
1921 void wait_all_dumpers_complete() {
1922 assert (_started == true, "wrong state when wait for dumper complete");
1923 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1924 while (_complete_number != _dumper_number) {
1925 ml.wait();
1926 }
1927 _started = false;
1928 }
1929 };
1930
1931 // The VM operation that performs the heap dump
1932 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask {
1933 private:
1934 static VM_HeapDumper* _global_dumper;
1935 static DumpWriter* _global_writer;
1936 DumpWriter* _local_writer;
1937 JavaThread* _oome_thread;
1938 Method* _oome_constructor;
1939 bool _gc_before_heap_dump;
1940 GrowableArray<Klass*>* _klass_map;
1941 ThreadStackTrace** _stack_traces;
1942 int _num_threads;
1943 // parallel heap dump support
1944 uint _num_dumper_threads;
1945 uint _num_writer_threads;
1946 DumperController* _dumper_controller;
1947 ParallelObjectIterator* _poi;
1948 HeapDumpLargeObjectList* _large_object_list;
1949
1950 // VMDumperType is for thread that dumps both heap and non-heap data.
1951 static const size_t VMDumperType = 0;
1952 static const size_t WriterType = 1;
1953 static const size_t DumperType = 2;
1954 // worker id of VMDumper thread.
1955 static const size_t VMDumperWorkerId = 0;
1956
1957 size_t get_worker_type(uint worker_id) {
1958 assert(_num_writer_threads >= 1, "Must be at least one writer");
1959 // worker id of VMDumper that dump heap and non-heap data
1960 if (worker_id == VMDumperWorkerId) {
1961 return VMDumperType;
1962 }
1963
1964 // worker id of dumper starts from 1, which only dump heap datar
1965 if (worker_id < _num_dumper_threads) {
1966 return DumperType;
1967 }
1968
1969 // worker id of writer starts from _num_dumper_threads
1970 return WriterType;
1971 }
1972
1973 void prepare_parallel_dump(uint num_total) {
1974 assert (_dumper_controller == nullptr, "dumper controller must be null");
1975 assert (num_total > 0, "active workers number must >= 1");
1976 // Dumper threads number must not be larger than active workers number.
1977 if (num_total < _num_dumper_threads) {
1978 _num_dumper_threads = num_total - 1;
1979 }
1980 // Calculate dumper and writer threads number.
1981 _num_writer_threads = num_total - _num_dumper_threads;
1982 // If dumper threads number is 1, only the VMThread works as a dumper.
1983 // If dumper threads number is equal to active workers, need at lest one worker thread as writer.
1984 if (_num_dumper_threads > 0 && _num_writer_threads == 0) {
1985 _num_writer_threads = 1;
1986 _num_dumper_threads = num_total - _num_writer_threads;
1987 }
1988 // Prepare parallel writer.
1989 if (_num_dumper_threads > 1) {
1990 ParDumpWriter::before_work();
1991 // Number of dumper threads that only iterate heap.
1992 uint _heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */;
1993 _dumper_controller = new (std::nothrow) DumperController(_heap_only_dumper_threads);
1994 }
1995 }
1996
1997 void finish_parallel_dump() {
1998 if (_num_dumper_threads > 1) {
1999 ParDumpWriter::after_work();
2000 }
2001 }
2002
2003 // accessors and setters
2004 static VM_HeapDumper* dumper() { assert(_global_dumper != nullptr, "Error"); return _global_dumper; }
2005 static DumpWriter* writer() { assert(_global_writer != nullptr, "Error"); return _global_writer; }
2006 void set_global_dumper() {
2007 assert(_global_dumper == nullptr, "Error");
2008 _global_dumper = this;
2009 }
2010 void set_global_writer() {
2011 assert(_global_writer == nullptr, "Error");
2012 _global_writer = _local_writer;
2013 }
2014 void clear_global_dumper() { _global_dumper = nullptr; }
2015 void clear_global_writer() { _global_writer = nullptr; }
2016
2017 bool skip_operation() const;
2018
2019 // writes a HPROF_LOAD_CLASS record
2020 static void do_load_class(Klass* k);
2021
2022 // writes a HPROF_GC_CLASS_DUMP record for the given class
2023 static void do_class_dump(Klass* k);
2024
2025 // HPROF_GC_ROOT_THREAD_OBJ records
2026 int do_thread(JavaThread* thread, u4 thread_serial_num);
2027 void do_threads();
2028
2029 void add_class_serial_number(Klass* k, int serial_num) {
2030 _klass_map->at_put_grow(serial_num, k);
2031 }
2032
2033 // HPROF_TRACE and HPROF_FRAME records
2034 void dump_stack_traces();
2035
2036 // large objects
2037 void dump_large_objects(ObjectClosure* writer);
2038
2039 public:
2040 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
2041 VM_GC_Operation(0 /* total collections, dummy, ignored */,
2042 GCCause::_heap_dump /* GC Cause */,
2043 0 /* total full collections, dummy, ignored */,
2044 gc_before_heap_dump),
2045 WorkerTask("dump heap") {
2046 _local_writer = writer;
2047 _gc_before_heap_dump = gc_before_heap_dump;
2048 _klass_map = new (mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
2049 _stack_traces = nullptr;
2050 _num_threads = 0;
2051 _num_dumper_threads = num_dump_threads;
2052 _dumper_controller = nullptr;
2053 _poi = nullptr;
2054 _large_object_list = new (std::nothrow) HeapDumpLargeObjectList();
2055 if (oome) {
2056 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
2057 // get OutOfMemoryError zero-parameter constructor
2058 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
2059 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
2060 vmSymbols::void_method_signature());
2061 // get thread throwing OOME when generating the heap dump at OOME
2062 _oome_thread = JavaThread::current();
2063 } else {
2064 _oome_thread = nullptr;
2065 _oome_constructor = nullptr;
2066 }
2067 }
2068
2069 ~VM_HeapDumper() {
2070 if (_stack_traces != nullptr) {
2071 for (int i=0; i < _num_threads; i++) {
2072 delete _stack_traces[i];
2073 }
2074 FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces);
2075 }
2076 if (_dumper_controller != nullptr) {
2077 delete _dumper_controller;
2078 _dumper_controller = nullptr;
2079 }
2080 delete _klass_map;
2081 delete _large_object_list;
2082 }
2083
2084 VMOp_Type type() const { return VMOp_HeapDumper; }
2085 virtual bool doit_prologue();
2086 void doit();
2087 void work(uint worker_id);
2088 };
2089
2090 VM_HeapDumper* VM_HeapDumper::_global_dumper = nullptr;
2091 DumpWriter* VM_HeapDumper::_global_writer = nullptr;
2092
2093 bool VM_HeapDumper::skip_operation() const {
2094 return false;
2095 }
2096
2097 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
2098 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
2099 writer->finish_dump_segment();
2100
2101 writer->write_u1(HPROF_HEAP_DUMP_END);
2102 writer->write_u4(0);
2103 writer->write_u4(0);
2104 }
2105
2106 // writes a HPROF_LOAD_CLASS record for the class
2107 void VM_HeapDumper::do_load_class(Klass* k) {
2108 static u4 class_serial_num = 0;
2109
2110 // len of HPROF_LOAD_CLASS record
2111 u4 remaining = 2*oopSize + 2*sizeof(u4);
2112
2113 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
2114
2115 // class serial number is just a number
2116 writer()->write_u4(++class_serial_num);
2117
2118 // class ID
2119 writer()->write_classID(k);
2120
2121 // add the Klass* and class serial number pair
2122 dumper()->add_class_serial_number(k, class_serial_num);
2123
2124 writer()->write_u4(STACK_TRACE_ID);
2125
2126 // class name ID
2127 Symbol* name = k->name();
2128 writer()->write_symbolID(name);
2129 }
2130
2131 // writes a HPROF_GC_CLASS_DUMP record for the given class
2132 void VM_HeapDumper::do_class_dump(Klass* k) {
2133 if (k->is_instance_klass()) {
2134 DumperSupport::dump_instance_class(writer(), k);
2135 } else {
2136 DumperSupport::dump_array_class(writer(), k);
2137 }
2138 }
2139
2140 // Walk the stack of the given thread.
2141 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
2142 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
2143 //
2144 // It returns the number of Java frames in this thread stack
2145 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
2146 JNILocalsDumper blk(writer(), thread_serial_num);
2147
2148 oop threadObj = java_thread->threadObj();
2149 assert(threadObj != nullptr, "sanity check");
2150
2151 int stack_depth = 0;
2152 if (java_thread->has_last_Java_frame()) {
2153
2154 // vframes are resource allocated
2155 Thread* current_thread = Thread::current();
2156 ResourceMark rm(current_thread);
2157 HandleMark hm(current_thread);
2158
2159 RegisterMap reg_map(java_thread,
2160 RegisterMap::UpdateMap::include,
2161 RegisterMap::ProcessFrames::include,
2162 RegisterMap::WalkContinuation::skip);
2163 frame f = java_thread->last_frame();
2164 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2165 frame* last_entry_frame = nullptr;
2166 int extra_frames = 0;
2167
2168 if (java_thread == _oome_thread && _oome_constructor != nullptr) {
2169 extra_frames++;
2170 }
2171 while (vf != nullptr) {
2172 blk.set_frame_number(stack_depth);
2173 if (vf->is_java_frame()) {
2174
2175 // java frame (interpreted, compiled, ...)
2176 javaVFrame *jvf = javaVFrame::cast(vf);
2177 if (!(jvf->method()->is_native())) {
2178 StackValueCollection* locals = jvf->locals();
2179 for (int slot=0; slot<locals->size(); slot++) {
2180 if (locals->at(slot)->type() == T_OBJECT) {
2181 oop o = locals->obj_at(slot)();
2182
2183 if (o != nullptr) {
2184 u4 size = 1 + sizeof(address) + 4 + 4;
2185 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2186 writer()->write_objectID(o);
2187 writer()->write_u4(thread_serial_num);
2188 writer()->write_u4((u4) (stack_depth + extra_frames));
2189 writer()->end_sub_record();
2190 }
2191 }
2192 }
2193 StackValueCollection *exprs = jvf->expressions();
2194 for(int index = 0; index < exprs->size(); index++) {
2195 if (exprs->at(index)->type() == T_OBJECT) {
2196 oop o = exprs->obj_at(index)();
2197 if (o != nullptr) {
2198 u4 size = 1 + sizeof(address) + 4 + 4;
2199 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2200 writer()->write_objectID(o);
2201 writer()->write_u4(thread_serial_num);
2202 writer()->write_u4((u4) (stack_depth + extra_frames));
2203 writer()->end_sub_record();
2204 }
2205 }
2206 }
2207 } else {
2208 // native frame
2209 if (stack_depth == 0) {
2210 // JNI locals for the top frame.
2211 java_thread->active_handles()->oops_do(&blk);
2212 } else {
2213 if (last_entry_frame != nullptr) {
2214 // JNI locals for the entry frame
2215 assert(last_entry_frame->is_entry_frame(), "checking");
2216 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
2217 }
2218 }
2219 }
2220 // increment only for Java frames
2221 stack_depth++;
2222 last_entry_frame = nullptr;
2223
2224 } else {
2225 // externalVFrame - if it's an entry frame then report any JNI locals
2226 // as roots when we find the corresponding native javaVFrame
2227 frame* fr = vf->frame_pointer();
2228 assert(fr != nullptr, "sanity check");
2229 if (fr->is_entry_frame()) {
2230 last_entry_frame = fr;
2231 }
2232 }
2233 vf = vf->sender();
2234 }
2235 } else {
2236 // no last java frame but there may be JNI locals
2237 java_thread->active_handles()->oops_do(&blk);
2238 }
2239 return stack_depth;
2240 }
2241
2242
2243 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
2244 // the stack so that locals and JNI locals are dumped.
2245 void VM_HeapDumper::do_threads() {
2246 for (int i=0; i < _num_threads; i++) {
2247 JavaThread* thread = _stack_traces[i]->thread();
2248 oop threadObj = thread->threadObj();
2249 u4 thread_serial_num = i+1;
2250 u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
2251 u4 size = 1 + sizeof(address) + 4 + 4;
2252 writer()->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
2253 writer()->write_objectID(threadObj);
2254 writer()->write_u4(thread_serial_num); // thread number
2255 writer()->write_u4(stack_serial_num); // stack trace serial number
2256 writer()->end_sub_record();
2257 int num_frames = do_thread(thread, thread_serial_num);
2258 assert(num_frames == _stack_traces[i]->get_stack_depth(),
2259 "total number of Java frames not matched");
2260 }
2261 }
2262
2263 bool VM_HeapDumper::doit_prologue() {
2264 if (_gc_before_heap_dump && UseZGC) {
2265 // ZGC cannot perform a synchronous GC cycle from within the VM thread.
2266 // So ZCollectedHeap::collect_as_vm_thread() is a noop. To respect the
2267 // _gc_before_heap_dump flag a synchronous GC cycle is performed from
2268 // the caller thread in the prologue.
2269 Universe::heap()->collect(GCCause::_heap_dump);
2270 }
2271 return VM_GC_Operation::doit_prologue();
2272 }
2273
2274
2275 // The VM operation that dumps the heap. The dump consists of the following
2276 // records:
2277 //
2278 // HPROF_HEADER
2279 // [HPROF_UTF8]*
2280 // [HPROF_LOAD_CLASS]*
2281 // [[HPROF_FRAME]*|HPROF_TRACE]*
2282 // [HPROF_GC_CLASS_DUMP]*
2283 // [HPROF_HEAP_DUMP_SEGMENT]*
2284 // HPROF_HEAP_DUMP_END
2285 //
2286 // The HPROF_TRACE records represent the stack traces where the heap dump
2287 // is generated and a "dummy trace" record which does not include
2288 // any frames. The dummy trace record is used to be referenced as the
2289 // unknown object alloc site.
2290 //
2291 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2292 // To allow the heap dump be generated in a single pass we remember the position
2293 // of the dump length and fix it up after all sub-records have been written.
2294 // To generate the sub-records we iterate over the heap, writing
2295 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2296 // records as we go. Once that is done we write records for some of the GC
2297 // roots.
2298
2299 void VM_HeapDumper::doit() {
2300
2301 CollectedHeap* ch = Universe::heap();
2302
2303 ch->ensure_parsability(false); // must happen, even if collection does
2304 // not happen (e.g. due to GCLocker)
2305
2306 if (_gc_before_heap_dump) {
2307 if (GCLocker::is_active()) {
2308 warning("GC locker is held; pre-heapdump GC was skipped");
2309 } else {
2310 ch->collect_as_vm_thread(GCCause::_heap_dump);
2311 }
2312 }
2313
2314 // At this point we should be the only dumper active, so
2315 // the following should be safe.
2316 set_global_dumper();
2317 set_global_writer();
2318
2319 WorkerThreads* workers = ch->safepoint_workers();
2320
2321 if (workers == nullptr) {
2322 // Use serial dump, set dumper threads and writer threads number to 1.
2323 _num_dumper_threads=1;
2324 _num_writer_threads=1;
2325 work(0);
2326 } else {
2327 prepare_parallel_dump(workers->active_workers());
2328 if (_num_dumper_threads > 1) {
2329 ParallelObjectIterator poi(_num_dumper_threads);
2330 _poi = &poi;
2331 workers->run_task(this);
2332 _poi = nullptr;
2333 } else {
2334 workers->run_task(this);
2335 }
2336 finish_parallel_dump();
2337 }
2338
2339 // Now we clear the global variables, so that a future dumper can run.
2340 clear_global_dumper();
2341 clear_global_writer();
2342 }
2343
2344 void VM_HeapDumper::work(uint worker_id) {
2345 if (worker_id != 0) {
2346 if (get_worker_type(worker_id) == WriterType) {
2347 writer()->writer_loop();
2348 return;
2349 }
2350 if (_num_dumper_threads > 1 && get_worker_type(worker_id) == DumperType) {
2351 _dumper_controller->wait_for_start_signal();
2352 }
2353 } else {
2354 // The worker 0 on all non-heap data dumping and part of heap iteration.
2355 // Write the file header - we always use 1.0.2
2356 const char* header = "JAVA PROFILE 1.0.2";
2357
2358 // header is few bytes long - no chance to overflow int
2359 writer()->write_raw(header, strlen(header) + 1); // NUL terminated
2360 writer()->write_u4(oopSize);
2361 // timestamp is current time in ms
2362 writer()->write_u8(os::javaTimeMillis());
2363 // HPROF_UTF8 records
2364 SymbolTableDumper sym_dumper(writer());
2365 SymbolTable::symbols_do(&sym_dumper);
2366
2367 // write HPROF_LOAD_CLASS records
2368 {
2369 LockedClassesDo locked_load_classes(&do_load_class);
2370 ClassLoaderDataGraph::classes_do(&locked_load_classes);
2371 }
2372
2373 // write HPROF_FRAME and HPROF_TRACE records
2374 // this must be called after _klass_map is built when iterating the classes above.
2375 dump_stack_traces();
2376
2377 // Writes HPROF_GC_CLASS_DUMP records
2378 {
2379 LockedClassesDo locked_dump_class(&do_class_dump);
2380 ClassLoaderDataGraph::classes_do(&locked_dump_class);
2381 }
2382
2383 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2384 do_threads();
2385
2386 // HPROF_GC_ROOT_JNI_GLOBAL
2387 JNIGlobalsDumper jni_dumper(writer());
2388 JNIHandles::oops_do(&jni_dumper);
2389 // technically not jni roots, but global roots
2390 // for things like preallocated throwable backtraces
2391 Universe::vm_global()->oops_do(&jni_dumper);
2392 // HPROF_GC_ROOT_STICKY_CLASS
2393 // These should be classes in the null class loader data, and not all classes
2394 // if !ClassUnloading
2395 StickyClassDumper class_dumper(writer());
2396 ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper);
2397 }
2398 // writes HPROF_GC_INSTANCE_DUMP records.
2399 // After each sub-record is written check_segment_length will be invoked
2400 // to check if the current segment exceeds a threshold. If so, a new
2401 // segment is started.
2402 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2403 // of the heap dump.
2404 if (_num_dumper_threads <= 1) {
2405 ResourceMark rm;
2406 HeapObjectDumper obj_dumper(writer());
2407 Universe::heap()->object_iterate(&obj_dumper);
2408 } else {
2409 assert(get_worker_type(worker_id) == DumperType
2410 || get_worker_type(worker_id) == VMDumperType,
2411 "must be dumper thread to do heap iteration");
2412 if (get_worker_type(worker_id) == VMDumperType) {
2413 // Clear global writer's buffer.
2414 writer()->finish_dump_segment(true);
2415 // Notify dumpers to start heap iteration.
2416 _dumper_controller->start_dump();
2417 }
2418 // Heap iteration.
2419 {
2420 ParDumpWriter pw(writer());
2421 {
2422 ResourceMark rm;
2423 HeapObjectDumper obj_dumper(&pw, _large_object_list);
2424 _poi->object_iterate(&obj_dumper, worker_id);
2425 }
2426
2427 if (get_worker_type(worker_id) == VMDumperType) {
2428 _dumper_controller->wait_all_dumpers_complete();
2429 // clear internal buffer;
2430 pw.finish_dump_segment(true);
2431 // refresh the global_writer's buffer and position;
2432 writer()->refresh();
2433 } else {
2434 pw.finish_dump_segment(true);
2435 _dumper_controller->dumper_complete();
2436 return;
2437 }
2438 }
2439 }
2440
2441 assert(get_worker_type(worker_id) == VMDumperType, "Heap dumper must be VMDumper");
2442 // Use writer() rather than ParDumpWriter to avoid memory consumption.
2443 ResourceMark rm;
2444 HeapObjectDumper obj_dumper(writer());
2445 dump_large_objects(&obj_dumper);
2446 // Writes the HPROF_HEAP_DUMP_END record.
2447 DumperSupport::end_of_dump(writer());
2448 // We are done with writing. Release the worker threads.
2449 writer()->deactivate();
2450 }
2451
2452 void VM_HeapDumper::dump_stack_traces() {
2453 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2454 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
2455 writer()->write_u4((u4) STACK_TRACE_ID);
2456 writer()->write_u4(0); // thread number
2457 writer()->write_u4(0); // frame count
2458
2459 _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);
2460 int frame_serial_num = 0;
2461 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
2462 oop threadObj = thread->threadObj();
2463 if (threadObj != nullptr && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
2464 // dump thread stack trace
2465 Thread* current_thread = Thread::current();
2466 ResourceMark rm(current_thread);
2467 HandleMark hm(current_thread);
2468
2469 ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
2470 stack_trace->dump_stack_at_safepoint(-1, /* ObjectMonitorsHashtable is not needed here */ nullptr, true);
2471 _stack_traces[_num_threads++] = stack_trace;
2472
2473 // write HPROF_FRAME records for this thread's stack trace
2474 int depth = stack_trace->get_stack_depth();
2475 int thread_frame_start = frame_serial_num;
2476 int extra_frames = 0;
2477 // write fake frame that makes it look like the thread, which caused OOME,
2478 // is in the OutOfMemoryError zero-parameter constructor
2479 if (thread == _oome_thread && _oome_constructor != nullptr) {
2480 int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());
2481 // the class serial number starts from 1
2482 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
2483 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
2484 _oome_constructor, 0);
2485 extra_frames++;
2486 }
2487 for (int j=0; j < depth; j++) {
2488 StackFrameInfo* frame = stack_trace->stack_frame_at(j);
2489 Method* m = frame->method();
2490 int class_serial_num = _klass_map->find(m->method_holder());
2491 // the class serial number starts from 1
2492 assert(class_serial_num > 0, "class not found");
2493 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
2494 }
2495 depth += extra_frames;
2496
2497 // write HPROF_TRACE record for one thread
2498 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
2499 int stack_serial_num = _num_threads + STACK_TRACE_ID;
2500 writer()->write_u4(stack_serial_num); // stack trace serial number
2501 writer()->write_u4((u4) _num_threads); // thread serial number
2502 writer()->write_u4(depth); // frame count
2503 for (int j=1; j <= depth; j++) {
2504 writer()->write_id(thread_frame_start + j);
2505 }
2506 }
2507 }
2508 }
2509
2510 // dump the large objects.
2511 void VM_HeapDumper::dump_large_objects(ObjectClosure* cl) {
2512 _large_object_list->drain(cl);
2513 }
2514
2515 // dump the heap to given path.
2516 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2517 assert(path != nullptr && strlen(path) > 0, "path missing");
2518
2519 // print message in interactive case
2520 if (out != nullptr) {
2521 out->print_cr("Dumping heap to %s ...", path);
2522 timer()->start();
2523 }
2524 // create JFR event
2525 EventHeapDump event;
2526
2527 AbstractCompressor* compressor = nullptr;
2528
2529 if (compression > 0) {
2530 compressor = new (std::nothrow) GZipCompressor(compression);
2531
2532 if (compressor == nullptr) {
2533 set_error("Could not allocate gzip compressor");
2534 return -1;
2535 }
2536 }
2537
2538 DumpWriter writer(new (std::nothrow) FileWriter(path, overwrite), compressor);
2539
2540 if (writer.error() != nullptr) {
2541 set_error(writer.error());
2542 if (out != nullptr) {
2543 out->print_cr("Unable to create %s: %s", path,
2544 (error() != nullptr) ? error() : "reason unknown");
2545 }
2546 return -1;
2547 }
2548
2549 // generate the dump
2550 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2551 if (Thread::current()->is_VM_thread()) {
2552 assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
2553 dumper.doit();
2554 } else {
2555 VMThread::execute(&dumper);
2556 }
2557
2558 // record any error that the writer may have encountered
2559 set_error(writer.error());
2560
2561 // emit JFR event
2562 if (error() == nullptr) {
2563 event.set_destination(path);
2564 event.set_gcBeforeDump(_gc_before_heap_dump);
2565 event.set_size(writer.bytes_written());
2566 event.set_onOutOfMemoryError(_oome);
2567 event.set_overwrite(overwrite);
2568 event.set_compression(compression);
2569 event.commit();
2570 } else {
2571 log_debug(cds, heap)("Error %s while dumping heap", error());
2572 }
2573
2574 // print message in interactive case
2575 if (out != nullptr) {
2576 timer()->stop();
2577 if (error() == nullptr) {
2578 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2579 writer.bytes_written(), timer()->seconds());
2580 } else {
2581 out->print_cr("Dump file is incomplete: %s", writer.error());
2582 }
2583 }
2584
2585 return (writer.error() == nullptr) ? 0 : -1;
2586 }
2587
2588 // stop timer (if still active), and free any error string we might be holding
2589 HeapDumper::~HeapDumper() {
2590 if (timer()->is_active()) {
2591 timer()->stop();
2592 }
2593 set_error(nullptr);
2594 }
2595
2596
2597 // returns the error string (resource allocated), or null
2598 char* HeapDumper::error_as_C_string() const {
2599 if (error() != nullptr) {
2600 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2601 strcpy(str, error());
2602 return str;
2603 } else {
2604 return nullptr;
2605 }
2606 }
2607
2608 // set the error string
2609 void HeapDumper::set_error(char const* error) {
2610 if (_error != nullptr) {
2611 os::free(_error);
2612 }
2613 if (error == nullptr) {
2614 _error = nullptr;
2615 } else {
2616 _error = os::strdup(error);
2617 assert(_error != nullptr, "allocation failure");
2618 }
2619 }
2620
2621 // Called by out-of-memory error reporting by a single Java thread
2622 // outside of a JVM safepoint
2623 void HeapDumper::dump_heap_from_oome() {
2624 HeapDumper::dump_heap(true);
2625 }
2626
2627 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2628 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2629 // callers are strictly serialized and guaranteed not to interfere below. For more
2630 // general use, however, this method will need modification to prevent
2631 // inteference when updating the static variables base_path and dump_file_seq below.
2632 void HeapDumper::dump_heap() {
2633 HeapDumper::dump_heap(false);
2634 }
2635
2636 void HeapDumper::dump_heap(bool oome) {
2637 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2638 static uint dump_file_seq = 0;
2639 char* my_path;
2640 const int max_digit_chars = 20;
2641
2642 const char* dump_file_name = "java_pid";
2643 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
2644
2645 // The dump file defaults to java_pid<pid>.hprof in the current working
2646 // directory. HeapDumpPath=<file> can be used to specify an alternative
2647 // dump file name or a directory where dump file is created.
2648 if (dump_file_seq == 0) { // first time in, we initialize base_path
2649 // Calculate potentially longest base path and check if we have enough
2650 // allocated statically.
2651 const size_t total_length =
2652 (HeapDumpPath == nullptr ? 0 : strlen(HeapDumpPath)) +
2653 strlen(os::file_separator()) + max_digit_chars +
2654 strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2655 if (total_length > sizeof(base_path)) {
2656 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2657 return;
2658 }
2659
2660 bool use_default_filename = true;
2661 if (HeapDumpPath == nullptr || HeapDumpPath[0] == '\0') {
2662 // HeapDumpPath=<file> not specified
2663 } else {
2664 strcpy(base_path, HeapDumpPath);
2665 // check if the path is a directory (must exist)
2666 DIR* dir = os::opendir(base_path);
2667 if (dir == nullptr) {
2668 use_default_filename = false;
2669 } else {
2670 // HeapDumpPath specified a directory. We append a file separator
2671 // (if needed).
2672 os::closedir(dir);
2673 size_t fs_len = strlen(os::file_separator());
2674 if (strlen(base_path) >= fs_len) {
2675 char* end = base_path;
2676 end += (strlen(base_path) - fs_len);
2677 if (strcmp(end, os::file_separator()) != 0) {
2678 strcat(base_path, os::file_separator());
2679 }
2680 }
2681 }
2682 }
2683 // If HeapDumpPath wasn't a file name then we append the default name
2684 if (use_default_filename) {
2685 const size_t dlen = strlen(base_path); // if heap dump dir specified
2686 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2687 dump_file_name, os::current_process_id(), dump_file_ext);
2688 }
2689 const size_t len = strlen(base_path) + 1;
2690 my_path = (char*)os::malloc(len, mtInternal);
2691 if (my_path == nullptr) {
2692 warning("Cannot create heap dump file. Out of system memory.");
2693 return;
2694 }
2695 strncpy(my_path, base_path, len);
2696 } else {
2697 // Append a sequence number id for dumps following the first
2698 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2699 my_path = (char*)os::malloc(len, mtInternal);
2700 if (my_path == nullptr) {
2701 warning("Cannot create heap dump file. Out of system memory.");
2702 return;
2703 }
2704 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2705 }
2706 dump_file_seq++; // increment seq number for next time we dump
2707
2708 HeapDumper dumper(false /* no GC before heap dump */,
2709 oome /* pass along out-of-memory-error flag */);
2710 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2711 os::free(my_path);
2712 }