1 /*
2 * Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/classLoaderData.inline.hpp"
28 #include "classfile/classLoaderDataGraph.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/symbolTable.hpp"
31 #include "classfile/vmClasses.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "gc/shared/gcLocker.hpp"
34 #include "gc/shared/gcVMOperations.hpp"
35 #include "gc/shared/workerThread.hpp"
36 #include "jfr/jfrEvents.hpp"
37 #include "memory/allocation.inline.hpp"
38 #include "memory/resourceArea.hpp"
39 #include "memory/universe.hpp"
40 #include "oops/klass.inline.hpp"
41 #include "oops/objArrayKlass.hpp"
42 #include "oops/objArrayOop.inline.hpp"
43 #include "oops/oop.inline.hpp"
44 #include "oops/typeArrayOop.inline.hpp"
45 #include "runtime/frame.inline.hpp"
46 #include "runtime/handles.inline.hpp"
47 #include "runtime/javaCalls.hpp"
48 #include "runtime/jniHandles.hpp"
49 #include "runtime/os.hpp"
50 #include "runtime/reflectionUtils.hpp"
51 #include "runtime/thread.inline.hpp"
52 #include "runtime/threadSMR.hpp"
53 #include "runtime/vframe.hpp"
54 #include "runtime/vmOperations.hpp"
55 #include "runtime/vmThread.hpp"
56 #include "services/heapDumper.hpp"
57 #include "services/heapDumperCompression.hpp"
58 #include "services/threadService.hpp"
59 #include "utilities/macros.hpp"
60 #include "utilities/ostream.hpp"
61
62 /*
63 * HPROF binary format - description copied from:
64 * src/share/demo/jvmti/hprof/hprof_io.c
65 *
66 *
67 * header "JAVA PROFILE 1.0.2" (0-terminated)
68 *
69 * u4 size of identifiers. Identifiers are used to represent
70 * UTF8 strings, objects, stack traces, etc. They usually
71 * have the same size as host pointers.
72 * u4 high word
73 * u4 low word number of milliseconds since 0:00 GMT, 1/1/70
74 * [record]* a sequence of records.
75 *
76 *
77 * Record format:
78 *
79 * u1 a TAG denoting the type of the record
80 * u4 number of *microseconds* since the time stamp in the
81 * header. (wraps around in a little more than an hour)
82 * u4 number of bytes *remaining* in the record. Note that
83 * this number excludes the tag and the length field itself.
84 * [u1]* BODY of the record (a sequence of bytes)
85 *
86 *
87 * The following TAGs are supported:
88 *
89 * TAG BODY notes
90 *----------------------------------------------------------
91 * HPROF_UTF8 a UTF8-encoded name
92 *
93 * id name ID
94 * [u1]* UTF8 characters (no trailing zero)
95 *
96 * HPROF_LOAD_CLASS a newly loaded class
97 *
98 * u4 class serial number (> 0)
99 * id class object ID
100 * u4 stack trace serial number
101 * id class name ID
102 *
103 * HPROF_UNLOAD_CLASS an unloading class
104 *
105 * u4 class serial_number
106 *
107 * HPROF_FRAME a Java stack frame
108 *
109 * id stack frame ID
110 * id method name ID
111 * id method signature ID
112 * id source file name ID
113 * u4 class serial number
114 * i4 line number. >0: normal
115 * -1: unknown
116 * -2: compiled method
117 * -3: native method
118 *
119 * HPROF_TRACE a Java stack trace
120 *
121 * u4 stack trace serial number
122 * u4 thread serial number
123 * u4 number of frames
124 * [id]* stack frame IDs
125 *
126 *
127 * HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC
128 *
129 * u2 flags 0x0001: incremental vs. complete
130 * 0x0002: sorted by allocation vs. live
131 * 0x0004: whether to force a GC
132 * u4 cutoff ratio
133 * u4 total live bytes
134 * u4 total live instances
135 * u8 total bytes allocated
136 * u8 total instances allocated
137 * u4 number of sites that follow
138 * [u1 is_array: 0: normal object
139 * 2: object array
140 * 4: boolean array
141 * 5: char array
142 * 6: float array
143 * 7: double array
144 * 8: byte array
145 * 9: short array
146 * 10: int array
147 * 11: long array
148 * u4 class serial number (may be zero during startup)
149 * u4 stack trace serial number
150 * u4 number of bytes alive
151 * u4 number of instances alive
152 * u4 number of bytes allocated
153 * u4]* number of instance allocated
154 *
155 * HPROF_START_THREAD a newly started thread.
156 *
157 * u4 thread serial number (> 0)
158 * id thread object ID
159 * u4 stack trace serial number
160 * id thread name ID
161 * id thread group name ID
162 * id thread group parent name ID
163 *
164 * HPROF_END_THREAD a terminating thread.
165 *
166 * u4 thread serial number
167 *
168 * HPROF_HEAP_SUMMARY heap summary
169 *
170 * u4 total live bytes
171 * u4 total live instances
172 * u8 total bytes allocated
173 * u8 total instances allocated
174 *
175 * HPROF_HEAP_DUMP denote a heap dump
176 *
177 * [heap dump sub-records]*
178 *
179 * There are four kinds of heap dump sub-records:
180 *
181 * u1 sub-record type
182 *
183 * HPROF_GC_ROOT_UNKNOWN unknown root
184 *
185 * id object ID
186 *
187 * HPROF_GC_ROOT_THREAD_OBJ thread object
188 *
189 * id thread object ID (may be 0 for a
190 * thread newly attached through JNI)
191 * u4 thread sequence number
192 * u4 stack trace sequence number
193 *
194 * HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root
195 *
196 * id object ID
197 * id JNI global ref ID
198 *
199 * HPROF_GC_ROOT_JNI_LOCAL JNI local ref
200 *
201 * id object ID
202 * u4 thread serial number
203 * u4 frame # in stack trace (-1 for empty)
204 *
205 * HPROF_GC_ROOT_JAVA_FRAME Java stack frame
206 *
207 * id object ID
208 * u4 thread serial number
209 * u4 frame # in stack trace (-1 for empty)
210 *
211 * HPROF_GC_ROOT_NATIVE_STACK Native stack
212 *
213 * id object ID
214 * u4 thread serial number
215 *
216 * HPROF_GC_ROOT_STICKY_CLASS System class
217 *
218 * id object ID
219 *
220 * HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block
221 *
222 * id object ID
223 * u4 thread serial number
224 *
225 * HPROF_GC_ROOT_MONITOR_USED Busy monitor
226 *
227 * id object ID
228 *
229 * HPROF_GC_CLASS_DUMP dump of a class object
230 *
231 * id class object ID
232 * u4 stack trace serial number
233 * id super class object ID
234 * id class loader object ID
235 * id signers object ID
236 * id protection domain object ID
237 * id reserved
238 * id reserved
239 *
240 * u4 instance size (in bytes)
241 *
242 * u2 size of constant pool
243 * [u2, constant pool index,
244 * ty, type
245 * 2: object
246 * 4: boolean
247 * 5: char
248 * 6: float
249 * 7: double
250 * 8: byte
251 * 9: short
252 * 10: int
253 * 11: long
254 * vl]* and value
255 *
256 * u2 number of static fields
257 * [id, static field name,
258 * ty, type,
259 * vl]* and value
260 *
261 * u2 number of inst. fields (not inc. super)
262 * [id, instance field name,
263 * ty]* type
264 *
265 * HPROF_GC_INSTANCE_DUMP dump of a normal object
266 *
267 * id object ID
268 * u4 stack trace serial number
269 * id class object ID
270 * u4 number of bytes that follow
271 * [vl]* instance field values (class, followed
272 * by super, super's super ...)
273 *
274 * HPROF_GC_OBJ_ARRAY_DUMP dump of an object array
275 *
276 * id array object ID
277 * u4 stack trace serial number
278 * u4 number of elements
279 * id array class ID
280 * [id]* elements
281 *
282 * HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array
283 *
284 * id array object ID
285 * u4 stack trace serial number
286 * u4 number of elements
287 * u1 element type
288 * 4: boolean array
289 * 5: char array
290 * 6: float array
291 * 7: double array
292 * 8: byte array
293 * 9: short array
294 * 10: int array
295 * 11: long array
296 * [u1]* elements
297 *
298 * HPROF_CPU_SAMPLES a set of sample traces of running threads
299 *
300 * u4 total number of samples
301 * u4 # of traces
302 * [u4 # of samples
303 * u4]* stack trace serial number
304 *
305 * HPROF_CONTROL_SETTINGS the settings of on/off switches
306 *
307 * u4 0x00000001: alloc traces on/off
308 * 0x00000002: cpu sampling on/off
309 * u2 stack trace depth
310 *
311 *
312 * When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
313 * be generated as a sequence of heap dump segments. This sequence is
314 * terminated by an end record. The additional tags allowed by format
315 * "JAVA PROFILE 1.0.2" are:
316 *
317 * HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment
318 *
319 * [heap dump sub-records]*
320 * The same sub-record types allowed by HPROF_HEAP_DUMP
321 *
322 * HPROF_HEAP_DUMP_END denotes the end of a heap dump
323 *
324 */
325
326
327 // HPROF tags
328
329 enum hprofTag : u1 {
330 // top-level records
331 HPROF_UTF8 = 0x01,
332 HPROF_LOAD_CLASS = 0x02,
333 HPROF_UNLOAD_CLASS = 0x03,
334 HPROF_FRAME = 0x04,
335 HPROF_TRACE = 0x05,
336 HPROF_ALLOC_SITES = 0x06,
337 HPROF_HEAP_SUMMARY = 0x07,
338 HPROF_START_THREAD = 0x0A,
339 HPROF_END_THREAD = 0x0B,
340 HPROF_HEAP_DUMP = 0x0C,
341 HPROF_CPU_SAMPLES = 0x0D,
342 HPROF_CONTROL_SETTINGS = 0x0E,
343
344 // 1.0.2 record types
345 HPROF_HEAP_DUMP_SEGMENT = 0x1C,
346 HPROF_HEAP_DUMP_END = 0x2C,
347
348 // field types
349 HPROF_ARRAY_OBJECT = 0x01,
350 HPROF_NORMAL_OBJECT = 0x02,
351 HPROF_BOOLEAN = 0x04,
352 HPROF_CHAR = 0x05,
353 HPROF_FLOAT = 0x06,
354 HPROF_DOUBLE = 0x07,
355 HPROF_BYTE = 0x08,
356 HPROF_SHORT = 0x09,
357 HPROF_INT = 0x0A,
358 HPROF_LONG = 0x0B,
359
360 // data-dump sub-records
361 HPROF_GC_ROOT_UNKNOWN = 0xFF,
362 HPROF_GC_ROOT_JNI_GLOBAL = 0x01,
363 HPROF_GC_ROOT_JNI_LOCAL = 0x02,
364 HPROF_GC_ROOT_JAVA_FRAME = 0x03,
365 HPROF_GC_ROOT_NATIVE_STACK = 0x04,
366 HPROF_GC_ROOT_STICKY_CLASS = 0x05,
367 HPROF_GC_ROOT_THREAD_BLOCK = 0x06,
368 HPROF_GC_ROOT_MONITOR_USED = 0x07,
369 HPROF_GC_ROOT_THREAD_OBJ = 0x08,
370 HPROF_GC_CLASS_DUMP = 0x20,
371 HPROF_GC_INSTANCE_DUMP = 0x21,
372 HPROF_GC_OBJ_ARRAY_DUMP = 0x22,
373 HPROF_GC_PRIM_ARRAY_DUMP = 0x23
374 };
375
376 // Default stack trace ID (used for dummy HPROF_TRACE record)
377 enum {
378 STACK_TRACE_ID = 1,
379 INITIAL_CLASS_COUNT = 200
380 };
381
382 // Supports I/O operations for a dump
383 // Base class for dump and parallel dump
384 class AbstractDumpWriter : public StackObj {
385 protected:
386 enum {
387 io_buffer_max_size = 1*M,
388 io_buffer_max_waste = 10*K,
389 dump_segment_header_size = 9
390 };
391
392 char* _buffer; // internal buffer
393 size_t _size;
394 size_t _pos;
395
396 bool _in_dump_segment; // Are we currently in a dump segment?
397 bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size?
398 DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record.
399 DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record().
400
401 virtual void flush(bool force = false) = 0;
402
403 char* buffer() const { return _buffer; }
404 size_t buffer_size() const { return _size; }
405 void set_position(size_t pos) { _pos = pos; }
406
407 // Can be called if we have enough room in the buffer.
408 void write_fast(const void* s, size_t len);
409
410 // Returns true if we have enough room in the buffer for 'len' bytes.
411 bool can_write_fast(size_t len);
412 public:
413 AbstractDumpWriter() :
414 _buffer(NULL),
415 _size(io_buffer_max_size),
416 _pos(0),
417 _in_dump_segment(false) { }
418
419 // total number of bytes written to the disk
420 virtual julong bytes_written() const = 0;
421 virtual char const* error() const = 0;
422
423 size_t position() const { return _pos; }
424 // writer functions
425 virtual void write_raw(const void* s, size_t len);
426 void write_u1(u1 x);
427 void write_u2(u2 x);
428 void write_u4(u4 x);
429 void write_u8(u8 x);
430 void write_objectID(oop o);
431 void write_symbolID(Symbol* o);
432 void write_classID(Klass* k);
433 void write_id(u4 x);
434
435 // Start a new sub-record. Starts a new heap dump segment if needed.
436 void start_sub_record(u1 tag, u4 len);
437 // Ends the current sub-record.
438 void end_sub_record();
439 // Finishes the current dump segment if not already finished.
440 void finish_dump_segment(bool force_flush = false);
441 // Refresh to get new buffer
442 void refresh() {
443 assert (_in_dump_segment ==false, "Sanity check");
444 _buffer = NULL;
445 _size = io_buffer_max_size;
446 _pos = 0;
447 // Force flush to guarantee data from parallel dumper are written.
448 flush(true);
449 }
450 // Called when finished to release the threads.
451 virtual void deactivate() = 0;
452 };
453
454 void AbstractDumpWriter::write_fast(const void* s, size_t len) {
455 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
456 assert(buffer_size() - position() >= len, "Must fit");
457 debug_only(_sub_record_left -= len);
458 memcpy(buffer() + position(), s, len);
459 set_position(position() + len);
460 }
461
462 bool AbstractDumpWriter::can_write_fast(size_t len) {
463 return buffer_size() - position() >= len;
464 }
465
466 // write raw bytes
467 void AbstractDumpWriter::write_raw(const void* s, size_t len) {
468 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
469 debug_only(_sub_record_left -= len);
470
471 // flush buffer to make room.
472 while (len > buffer_size() - position()) {
473 assert(!_in_dump_segment || _is_huge_sub_record,
474 "Cannot overflow in non-huge sub-record.");
475 size_t to_write = buffer_size() - position();
476 memcpy(buffer() + position(), s, to_write);
477 s = (void*) ((char*) s + to_write);
478 len -= to_write;
479 set_position(position() + to_write);
480 flush();
481 }
482
483 memcpy(buffer() + position(), s, len);
484 set_position(position() + len);
485 }
486
487 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
488 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
489 else write_raw((p), (len)); } while (0)
490
491 void AbstractDumpWriter::write_u1(u1 x) {
492 WRITE_KNOWN_TYPE(&x, 1);
493 }
494
495 void AbstractDumpWriter::write_u2(u2 x) {
496 u2 v;
497 Bytes::put_Java_u2((address)&v, x);
498 WRITE_KNOWN_TYPE(&v, 2);
499 }
500
501 void AbstractDumpWriter::write_u4(u4 x) {
502 u4 v;
503 Bytes::put_Java_u4((address)&v, x);
504 WRITE_KNOWN_TYPE(&v, 4);
505 }
506
507 void AbstractDumpWriter::write_u8(u8 x) {
508 u8 v;
509 Bytes::put_Java_u8((address)&v, x);
510 WRITE_KNOWN_TYPE(&v, 8);
511 }
512
513 void AbstractDumpWriter::write_objectID(oop o) {
514 address a = cast_from_oop<address>(o);
515 #ifdef _LP64
516 write_u8((u8)a);
517 #else
518 write_u4((u4)a);
519 #endif
520 }
521
522 void AbstractDumpWriter::write_symbolID(Symbol* s) {
523 address a = (address)((uintptr_t)s);
524 #ifdef _LP64
525 write_u8((u8)a);
526 #else
527 write_u4((u4)a);
528 #endif
529 }
530
531 void AbstractDumpWriter::write_id(u4 x) {
532 #ifdef _LP64
533 write_u8((u8) x);
534 #else
535 write_u4(x);
536 #endif
537 }
538
539 // We use java mirror as the class ID
540 void AbstractDumpWriter::write_classID(Klass* k) {
541 write_objectID(k->java_mirror());
542 }
543
544 void AbstractDumpWriter::finish_dump_segment(bool force_flush) {
545 if (_in_dump_segment) {
546 assert(_sub_record_left == 0, "Last sub-record not written completely");
547 assert(_sub_record_ended, "sub-record must have ended");
548
549 // Fix up the dump segment length if we haven't written a huge sub-record last
550 // (in which case the segment length was already set to the correct value initially).
551 if (!_is_huge_sub_record) {
552 assert(position() > dump_segment_header_size, "Dump segment should have some content");
553 Bytes::put_Java_u4((address) (buffer() + 5),
554 (u4) (position() - dump_segment_header_size));
555 } else {
556 // Finish process huge sub record
557 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
558 _is_huge_sub_record = false;
559 }
560
561 _in_dump_segment = false;
562 flush(force_flush);
563 }
564 }
565
566 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
567 if (!_in_dump_segment) {
568 if (position() > 0) {
569 flush();
570 }
571
572 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
573
574 write_u1(HPROF_HEAP_DUMP_SEGMENT);
575 write_u4(0); // timestamp
576 // Will be fixed up later if we add more sub-records. If this is a huge sub-record,
577 // this is already the correct length, since we don't add more sub-records.
578 write_u4(len);
579 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsitent size!");
580 _in_dump_segment = true;
581 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
582 } else if (_is_huge_sub_record || (len > buffer_size() - position())) {
583 // This object will not fit in completely or the last sub-record was huge.
584 // Finish the current segement and try again.
585 finish_dump_segment();
586 start_sub_record(tag, len);
587
588 return;
589 }
590
591 debug_only(_sub_record_left = len);
592 debug_only(_sub_record_ended = false);
593
594 write_u1(tag);
595 }
596
597 void AbstractDumpWriter::end_sub_record() {
598 assert(_in_dump_segment, "must be in dump segment");
599 assert(_sub_record_left == 0, "sub-record not written completely");
600 assert(!_sub_record_ended, "Must not have ended yet");
601 debug_only(_sub_record_ended = true);
602 }
603
604 // Supports I/O operations for a dump
605
606 class DumpWriter : public AbstractDumpWriter {
607 private:
608 CompressionBackend _backend; // Does the actual writing.
609 protected:
610 void flush(bool force = false) override;
611
612 public:
613 // Takes ownership of the writer and compressor.
614 DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor);
615
616 // total number of bytes written to the disk
617 julong bytes_written() const override { return (julong) _backend.get_written(); }
618
619 char const* error() const override { return _backend.error(); }
620
621 // Called by threads used for parallel writing.
622 void writer_loop() { _backend.thread_loop(); }
623 // Called when finish to release the threads.
624 void deactivate() override { flush(); _backend.deactivate(); }
625 // Get the backend pointer, used by parallel dump writer.
626 CompressionBackend* backend_ptr() { return &_backend; }
627
628 };
629
630 // Check for error after constructing the object and destroy it in case of an error.
631 DumpWriter::DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor) :
632 AbstractDumpWriter(),
633 _backend(writer, compressor, io_buffer_max_size, io_buffer_max_waste) {
634 flush();
635 }
636
637 // flush any buffered bytes to the file
638 void DumpWriter::flush(bool force) {
639 _backend.get_new_buffer(&_buffer, &_pos, &_size, force);
640 }
641
642 // Buffer queue used for parallel dump.
643 struct ParWriterBufferQueueElem {
644 char* _buffer;
645 size_t _used;
646 ParWriterBufferQueueElem* _next;
647 };
648
649 class ParWriterBufferQueue : public CHeapObj<mtInternal> {
650 private:
651 ParWriterBufferQueueElem* _head;
652 ParWriterBufferQueueElem* _tail;
653 uint _length;
654 public:
655 ParWriterBufferQueue() : _head(NULL), _tail(NULL), _length(0) { }
656
657 void enqueue(ParWriterBufferQueueElem* entry) {
658 if (_head == NULL) {
659 assert(is_empty() && _tail == NULL, "Sanity check");
660 _head = _tail = entry;
661 } else {
662 assert ((_tail->_next == NULL && _tail->_buffer != NULL), "Buffer queue is polluted");
663 _tail->_next = entry;
664 _tail = entry;
665 }
666 _length++;
667 assert(_tail->_next == NULL, "Bufer queue is polluted");
668 }
669
670 ParWriterBufferQueueElem* dequeue() {
671 if (_head == NULL) return NULL;
672 ParWriterBufferQueueElem* entry = _head;
673 assert (entry->_buffer != NULL, "polluted buffer in writer list");
674 _head = entry->_next;
675 if (_head == NULL) {
676 _tail = NULL;
677 }
678 entry->_next = NULL;
679 _length--;
680 return entry;
681 }
682
683 bool is_empty() {
684 return _length == 0;
685 }
686
687 uint length() { return _length; }
688 };
689
690 // Support parallel heap dump.
691 class ParDumpWriter : public AbstractDumpWriter {
692 private:
693 // Lock used to guarantee the integrity of multiple buffers writing.
694 static Monitor* _lock;
695 // Pointer of backend from global DumpWriter.
696 CompressionBackend* _backend_ptr;
697 char const * _err;
698 ParWriterBufferQueue* _buffer_queue;
699 size_t _internal_buffer_used;
700 char* _buffer_base;
701 bool _split_data;
702 static const uint BackendFlushThreshold = 2;
703 protected:
704 void flush(bool force = false) override {
705 assert(_pos != 0, "must not be zero");
706 if (_pos != 0) {
707 refresh_buffer();
708 }
709
710 if (_split_data || _is_huge_sub_record) {
711 return;
712 }
713
714 if (should_flush_buf_list(force)) {
715 assert(!_in_dump_segment && !_split_data && !_is_huge_sub_record, "incomplete data send to backend!\n");
716 flush_to_backend(force);
717 }
718 }
719
720 public:
721 // Check for error after constructing the object and destroy it in case of an error.
722 ParDumpWriter(DumpWriter* dw) :
723 AbstractDumpWriter(),
724 _backend_ptr(dw->backend_ptr()),
725 _buffer_queue((new (std::nothrow) ParWriterBufferQueue())),
726 _buffer_base(NULL),
727 _split_data(false) {
728 // prepare internal buffer
729 allocate_internal_buffer();
730 }
731
732 ~ParDumpWriter() {
733 assert(_buffer_queue != NULL, "Sanity check");
734 assert((_internal_buffer_used == 0) && (_buffer_queue->is_empty()),
735 "All data must be send to backend");
736 if (_buffer_base != NULL) {
737 os::free(_buffer_base);
738 _buffer_base = NULL;
739 }
740 delete _buffer_queue;
741 _buffer_queue = NULL;
742 }
743
744 // total number of bytes written to the disk
745 julong bytes_written() const override { return (julong) _backend_ptr->get_written(); }
746 char const* error() const override { return _err == NULL ? _backend_ptr->error() : _err; }
747
748 static void before_work() {
749 assert(_lock == NULL, "ParDumpWriter lock must be initialized only once");
750 _lock = new (std::nothrow) PaddedMonitor(Mutex::safepoint, "ParallelHProfWriter_lock");
751 }
752
753 static void after_work() {
754 assert(_lock != NULL, "ParDumpWriter lock is not initialized");
755 delete _lock;
756 _lock = NULL;
757 }
758
759 // write raw bytes
760 void write_raw(const void* s, size_t len) override {
761 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
762 debug_only(_sub_record_left -= len);
763 assert(!_split_data, "Invalid split data");
764 _split_data = true;
765 // flush buffer to make room.
766 while (len > buffer_size() - position()) {
767 assert(!_in_dump_segment || _is_huge_sub_record,
768 "Cannot overflow in non-huge sub-record.");
769 size_t to_write = buffer_size() - position();
770 memcpy(buffer() + position(), s, to_write);
771 s = (void*) ((char*) s + to_write);
772 len -= to_write;
773 set_position(position() + to_write);
774 flush();
775 }
776 _split_data = false;
777 memcpy(buffer() + position(), s, len);
778 set_position(position() + len);
779 }
780
781 void deactivate() override { flush(true); _backend_ptr->deactivate(); }
782
783 private:
784 void allocate_internal_buffer() {
785 assert(_buffer_queue != NULL, "Internal buffer queue is not ready when allocate internal buffer");
786 assert(_buffer == NULL && _buffer_base == NULL, "current buffer must be NULL before allocate");
787 _buffer_base = _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
788 if (_buffer == NULL) {
789 set_error("Could not allocate buffer for writer");
790 return;
791 }
792 _pos = 0;
793 _internal_buffer_used = 0;
794 _size = io_buffer_max_size;
795 }
796
797 void set_error(char const* new_error) {
798 if ((new_error != NULL) && (_err == NULL)) {
799 _err = new_error;
800 }
801 }
802
803 // Add buffer to internal list
804 void refresh_buffer() {
805 size_t expected_total = _internal_buffer_used + _pos;
806 if (expected_total < io_buffer_max_size - io_buffer_max_waste) {
807 // reuse current buffer.
808 _internal_buffer_used = expected_total;
809 assert(_size - _pos == io_buffer_max_size - expected_total, "illegal resize of buffer");
810 _size -= _pos;
811 _buffer += _pos;
812 _pos = 0;
813
814 return;
815 }
816 // It is not possible here that expected_total is larger than io_buffer_max_size because
817 // of limitation in write_xxx().
818 assert(expected_total <= io_buffer_max_size, "buffer overflow");
819 assert(_buffer - _buffer_base <= io_buffer_max_size, "internal buffer overflow");
820 ParWriterBufferQueueElem* entry =
821 (ParWriterBufferQueueElem*)os::malloc(sizeof(ParWriterBufferQueueElem), mtInternal);
822 if (entry == NULL) {
823 set_error("Heap dumper can allocate memory");
824 return;
825 }
826 entry->_buffer = _buffer_base;
827 entry->_used = expected_total;
828 entry->_next = NULL;
829 // add to internal buffer queue
830 _buffer_queue->enqueue(entry);
831 _buffer_base =_buffer = NULL;
832 allocate_internal_buffer();
833 }
834
835 void reclaim_entry(ParWriterBufferQueueElem* entry) {
836 assert(entry != NULL && entry->_buffer != NULL, "Invalid entry to reclaim");
837 os::free(entry->_buffer);
838 entry->_buffer = NULL;
839 os::free(entry);
840 }
841
842 void flush_buffer(char* buffer, size_t used) {
843 assert(_lock->owner() == Thread::current(), "flush buffer must hold lock");
844 size_t max = io_buffer_max_size;
845 // get_new_buffer
846 _backend_ptr->flush_external_buffer(buffer, used, max);
847 }
848
849 bool should_flush_buf_list(bool force) {
850 return force || _buffer_queue->length() > BackendFlushThreshold;
851 }
852
853 void flush_to_backend(bool force) {
854 // Guarantee there is only one writer updating the backend buffers.
855 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
856 while (!_buffer_queue->is_empty()) {
857 ParWriterBufferQueueElem* entry = _buffer_queue->dequeue();
858 flush_buffer(entry->_buffer, entry->_used);
859 // Delete buffer and entry.
860 reclaim_entry(entry);
861 entry = NULL;
862 }
863 assert(_pos == 0, "available buffer must be empty before flush");
864 // Flush internal buffer.
865 if (_internal_buffer_used > 0) {
866 flush_buffer(_buffer_base, _internal_buffer_used);
867 os::free(_buffer_base);
868 _pos = 0;
869 _internal_buffer_used = 0;
870 _buffer_base = _buffer = NULL;
871 // Allocate internal buffer for future use.
872 allocate_internal_buffer();
873 }
874 }
875 };
876
877 Monitor* ParDumpWriter::_lock = NULL;
878
879 // Support class with a collection of functions used when dumping the heap
880
881 class DumperSupport : AllStatic {
882 public:
883
884 // write a header of the given type
885 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
886
887 // returns hprof tag for the given type signature
888 static hprofTag sig2tag(Symbol* sig);
889 // returns hprof tag for the given basic type
890 static hprofTag type2tag(BasicType type);
891 // Returns the size of the data to write.
892 static u4 sig2size(Symbol* sig);
893
894 // returns the size of the instance of the given class
895 static u4 instance_size(Klass* k);
896
897 // dump a jfloat
898 static void dump_float(AbstractDumpWriter* writer, jfloat f);
899 // dump a jdouble
900 static void dump_double(AbstractDumpWriter* writer, jdouble d);
901 // dumps the raw value of the given field
902 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
903 // returns the size of the static fields; also counts the static fields
904 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
905 // dumps static fields of the given class
906 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
907 // dump the raw values of the instance fields of the given object
908 static void dump_instance_fields(AbstractDumpWriter* writer, oop o);
909 // get the count of the instance fields for a given class
910 static u2 get_instance_fields_count(InstanceKlass* ik);
911 // dumps the definition of the instance fields for a given class
912 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
913 // creates HPROF_GC_INSTANCE_DUMP record for the given object
914 static void dump_instance(AbstractDumpWriter* writer, oop o);
915 // creates HPROF_GC_CLASS_DUMP record for the given instance class
916 static void dump_instance_class(AbstractDumpWriter* writer, Klass* k);
917 // creates HPROF_GC_CLASS_DUMP record for a given array class
918 static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
919
920 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
921 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
922 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
923 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
924 // create HPROF_FRAME record for the given method and bci
925 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
926
927 // check if we need to truncate an array
928 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
929
930 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
931 static void end_of_dump(AbstractDumpWriter* writer);
932
933 static oop mask_dormant_archived_object(oop o) {
934 if (o != NULL && o->klass()->java_mirror() == NULL) {
935 // Ignore this object since the corresponding java mirror is not loaded.
936 // Might be a dormant archive object.
937 return NULL;
938 } else {
939 return o;
940 }
941 }
942 };
943
944 // write a header of the given type
945 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
946 writer->write_u1(tag);
947 writer->write_u4(0); // current ticks
948 writer->write_u4(len);
949 }
950
951 // returns hprof tag for the given type signature
952 hprofTag DumperSupport::sig2tag(Symbol* sig) {
953 switch (sig->char_at(0)) {
954 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
955 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
956 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
957 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
958 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
959 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
960 case JVM_SIGNATURE_INT : return HPROF_INT;
961 case JVM_SIGNATURE_LONG : return HPROF_LONG;
962 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
963 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
964 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
965 }
966 }
967
968 hprofTag DumperSupport::type2tag(BasicType type) {
969 switch (type) {
970 case T_BYTE : return HPROF_BYTE;
971 case T_CHAR : return HPROF_CHAR;
972 case T_FLOAT : return HPROF_FLOAT;
973 case T_DOUBLE : return HPROF_DOUBLE;
974 case T_INT : return HPROF_INT;
975 case T_LONG : return HPROF_LONG;
976 case T_SHORT : return HPROF_SHORT;
977 case T_BOOLEAN : return HPROF_BOOLEAN;
978 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
979 }
980 }
981
982 u4 DumperSupport::sig2size(Symbol* sig) {
983 switch (sig->char_at(0)) {
984 case JVM_SIGNATURE_CLASS:
985 case JVM_SIGNATURE_ARRAY: return sizeof(address);
986 case JVM_SIGNATURE_BOOLEAN:
987 case JVM_SIGNATURE_BYTE: return 1;
988 case JVM_SIGNATURE_SHORT:
989 case JVM_SIGNATURE_CHAR: return 2;
990 case JVM_SIGNATURE_INT:
991 case JVM_SIGNATURE_FLOAT: return 4;
992 case JVM_SIGNATURE_LONG:
993 case JVM_SIGNATURE_DOUBLE: return 8;
994 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
995 }
996 }
997
998 template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
999 T to;
1000 static_assert(sizeof(to) == sizeof(from), "must be of the same size");
1001 memcpy(&to, &from, sizeof(to));
1002 return to;
1003 }
1004
1005 // dump a jfloat
1006 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
1007 if (g_isnan(f)) {
1008 writer->write_u4(0x7fc00000); // collapsing NaNs
1009 } else {
1010 writer->write_u4(bit_cast<u4>(f));
1011 }
1012 }
1013
1014 // dump a jdouble
1015 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
1016 if (g_isnan(d)) {
1017 writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
1018 } else {
1019 writer->write_u8(bit_cast<u8>(d));
1020 }
1021 }
1022
1023 // dumps the raw value of the given field
1024 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
1025 switch (type) {
1026 case JVM_SIGNATURE_CLASS :
1027 case JVM_SIGNATURE_ARRAY : {
1028 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
1029 if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
1030 ResourceMark rm;
1031 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
1032 p2i(o), o->klass()->external_name(),
1033 p2i(obj), obj->klass()->external_name());
1034 }
1035 o = mask_dormant_archived_object(o);
1036 assert(oopDesc::is_oop_or_null(o), "Expected an oop or NULL at " PTR_FORMAT, p2i(o));
1037 writer->write_objectID(o);
1038 break;
1039 }
1040 case JVM_SIGNATURE_BYTE : {
1041 jbyte b = obj->byte_field(offset);
1042 writer->write_u1(b);
1043 break;
1044 }
1045 case JVM_SIGNATURE_CHAR : {
1046 jchar c = obj->char_field(offset);
1047 writer->write_u2(c);
1048 break;
1049 }
1050 case JVM_SIGNATURE_SHORT : {
1051 jshort s = obj->short_field(offset);
1052 writer->write_u2(s);
1053 break;
1054 }
1055 case JVM_SIGNATURE_FLOAT : {
1056 jfloat f = obj->float_field(offset);
1057 dump_float(writer, f);
1058 break;
1059 }
1060 case JVM_SIGNATURE_DOUBLE : {
1061 jdouble d = obj->double_field(offset);
1062 dump_double(writer, d);
1063 break;
1064 }
1065 case JVM_SIGNATURE_INT : {
1066 jint i = obj->int_field(offset);
1067 writer->write_u4(i);
1068 break;
1069 }
1070 case JVM_SIGNATURE_LONG : {
1071 jlong l = obj->long_field(offset);
1072 writer->write_u8(l);
1073 break;
1074 }
1075 case JVM_SIGNATURE_BOOLEAN : {
1076 jboolean b = obj->bool_field(offset);
1077 writer->write_u1(b);
1078 break;
1079 }
1080 default : {
1081 ShouldNotReachHere();
1082 break;
1083 }
1084 }
1085 }
1086
1087 // returns the size of the instance of the given class
1088 u4 DumperSupport::instance_size(Klass* k) {
1089 InstanceKlass* ik = InstanceKlass::cast(k);
1090 u4 size = 0;
1091
1092 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
1093 if (!fld.access_flags().is_static()) {
1094 size += sig2size(fld.signature());
1095 }
1096 }
1097 return size;
1098 }
1099
1100 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1101 field_count = 0;
1102 u4 size = 0;
1103
1104 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
1105 if (fldc.access_flags().is_static()) {
1106 field_count++;
1107 size += sig2size(fldc.signature());
1108 }
1109 }
1110
1111 // Add in resolved_references which is referenced by the cpCache
1112 // The resolved_references is an array per InstanceKlass holding the
1113 // strings and other oops resolved from the constant pool.
1114 oop resolved_references = ik->constants()->resolved_references_or_null();
1115 if (resolved_references != NULL) {
1116 field_count++;
1117 size += sizeof(address);
1118
1119 // Add in the resolved_references of the used previous versions of the class
1120 // in the case of RedefineClasses
1121 InstanceKlass* prev = ik->previous_versions();
1122 while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
1123 field_count++;
1124 size += sizeof(address);
1125 prev = prev->previous_versions();
1126 }
1127 }
1128
1129 // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
1130 // arrays.
1131 oop init_lock = ik->init_lock();
1132 if (init_lock != NULL) {
1133 field_count++;
1134 size += sizeof(address);
1135 }
1136
1137 // We write the value itself plus a name and a one byte type tag per field.
1138 return size + field_count * (sizeof(address) + 1);
1139 }
1140
1141 // dumps static fields of the given class
1142 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1143 InstanceKlass* ik = InstanceKlass::cast(k);
1144
1145 // dump the field descriptors and raw values
1146 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
1147 if (fld.access_flags().is_static()) {
1148 Symbol* sig = fld.signature();
1149
1150 writer->write_symbolID(fld.name()); // name
1151 writer->write_u1(sig2tag(sig)); // type
1152
1153 // value
1154 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1155 }
1156 }
1157
1158 // Add resolved_references for each class that has them
1159 oop resolved_references = ik->constants()->resolved_references_or_null();
1160 if (resolved_references != NULL) {
1161 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1162 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1163 writer->write_objectID(resolved_references);
1164
1165 // Also write any previous versions
1166 InstanceKlass* prev = ik->previous_versions();
1167 while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
1168 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1169 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1170 writer->write_objectID(prev->constants()->resolved_references());
1171 prev = prev->previous_versions();
1172 }
1173 }
1174
1175 // Add init lock to the end if the class is not yet initialized
1176 oop init_lock = ik->init_lock();
1177 if (init_lock != NULL) {
1178 writer->write_symbolID(vmSymbols::init_lock_name()); // name
1179 writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
1180 writer->write_objectID(init_lock);
1181 }
1182 }
1183
1184 // dump the raw values of the instance fields of the given object
1185 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o) {
1186 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1187
1188 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
1189 if (!fld.access_flags().is_static()) {
1190 Symbol* sig = fld.signature();
1191 dump_field_value(writer, sig->char_at(0), o, fld.offset());
1192 }
1193 }
1194 }
1195
1196 // dumps the definition of the instance fields for a given class
1197 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1198 u2 field_count = 0;
1199
1200 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
1201 if (!fldc.access_flags().is_static()) field_count++;
1202 }
1203
1204 return field_count;
1205 }
1206
1207 // dumps the definition of the instance fields for a given class
1208 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1209 InstanceKlass* ik = InstanceKlass::cast(k);
1210
1211 // dump the field descriptors
1212 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
1213 if (!fld.access_flags().is_static()) {
1214 Symbol* sig = fld.signature();
1215
1216 writer->write_symbolID(fld.name()); // name
1217 writer->write_u1(sig2tag(sig)); // type
1218 }
1219 }
1220 }
1221
1222 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1223 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o) {
1224 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1225 u4 is = instance_size(ik);
1226 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1227
1228 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1229 writer->write_objectID(o);
1230 writer->write_u4(STACK_TRACE_ID);
1231
1232 // class ID
1233 writer->write_classID(ik);
1234
1235 // number of bytes that follow
1236 writer->write_u4(is);
1237
1238 // field values
1239 dump_instance_fields(writer, o);
1240
1241 writer->end_sub_record();
1242 }
1243
1244 // creates HPROF_GC_CLASS_DUMP record for the given instance class
1245 void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) {
1246 InstanceKlass* ik = InstanceKlass::cast(k);
1247
1248 // We can safepoint and do a heap dump at a point where we have a Klass,
1249 // but no java mirror class has been setup for it. So we need to check
1250 // that the class is at least loaded, to avoid crash from a null mirror.
1251 if (!ik->is_loaded()) {
1252 return;
1253 }
1254
1255 u2 static_fields_count = 0;
1256 u4 static_size = get_static_fields_size(ik, static_fields_count);
1257 u2 instance_fields_count = get_instance_fields_count(ik);
1258 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1259 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size;
1260
1261 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1262
1263 // class ID
1264 writer->write_classID(ik);
1265 writer->write_u4(STACK_TRACE_ID);
1266
1267 // super class ID
1268 InstanceKlass* java_super = ik->java_super();
1269 if (java_super == NULL) {
1270 writer->write_objectID(oop(NULL));
1271 } else {
1272 writer->write_classID(java_super);
1273 }
1274
1275 writer->write_objectID(ik->class_loader());
1276 writer->write_objectID(ik->signers());
1277 writer->write_objectID(ik->protection_domain());
1278
1279 // reserved
1280 writer->write_objectID(oop(NULL));
1281 writer->write_objectID(oop(NULL));
1282
1283 // instance size
1284 writer->write_u4(DumperSupport::instance_size(ik));
1285
1286 // size of constant pool - ignored by HAT 1.1
1287 writer->write_u2(0);
1288
1289 // static fields
1290 writer->write_u2(static_fields_count);
1291 dump_static_fields(writer, ik);
1292
1293 // description of instance fields
1294 writer->write_u2(instance_fields_count);
1295 dump_instance_field_descriptors(writer, ik);
1296
1297 writer->end_sub_record();
1298 }
1299
1300 // creates HPROF_GC_CLASS_DUMP record for the given array class
1301 void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
1302 InstanceKlass* ik = NULL; // bottom class for object arrays, NULL for primitive type arrays
1303 if (k->is_objArray_klass()) {
1304 Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
1305 assert(bk != NULL, "checking");
1306 if (bk->is_instance_klass()) {
1307 ik = InstanceKlass::cast(bk);
1308 }
1309 }
1310
1311 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1312 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1313 writer->write_classID(k);
1314 writer->write_u4(STACK_TRACE_ID);
1315
1316 // super class of array classes is java.lang.Object
1317 InstanceKlass* java_super = k->java_super();
1318 assert(java_super != NULL, "checking");
1319 writer->write_classID(java_super);
1320
1321 writer->write_objectID(ik == NULL ? oop(NULL) : ik->class_loader());
1322 writer->write_objectID(ik == NULL ? oop(NULL) : ik->signers());
1323 writer->write_objectID(ik == NULL ? oop(NULL) : ik->protection_domain());
1324
1325 writer->write_objectID(oop(NULL)); // reserved
1326 writer->write_objectID(oop(NULL));
1327 writer->write_u4(0); // instance size
1328 writer->write_u2(0); // constant pool
1329 writer->write_u2(0); // static fields
1330 writer->write_u2(0); // instance fields
1331
1332 writer->end_sub_record();
1333
1334 }
1335
1336 // Hprof uses an u4 as record length field,
1337 // which means we need to truncate arrays that are too long.
1338 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1339 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1340 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1341
1342 int length = array->length();
1343
1344 int type_size;
1345 if (type == T_OBJECT) {
1346 type_size = sizeof(address);
1347 } else {
1348 type_size = type2aelembytes(type);
1349 }
1350
1351 size_t length_in_bytes = (size_t)length * type_size;
1352 uint max_bytes = max_juint - header_size;
1353
1354 if (length_in_bytes > max_bytes) {
1355 length = max_bytes / type_size;
1356 length_in_bytes = (size_t)length * type_size;
1357
1358 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1359 type2name_tab[type], array->length(), length);
1360 }
1361 return length;
1362 }
1363
1364 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1365 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1366 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1367 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1368 int length = calculate_array_max_length(writer, array, header_size);
1369 u4 size = header_size + length * sizeof(address);
1370
1371 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1372 writer->write_objectID(array);
1373 writer->write_u4(STACK_TRACE_ID);
1374 writer->write_u4(length);
1375
1376 // array class ID
1377 writer->write_classID(array->klass());
1378
1379 // [id]* elements
1380 for (int index = 0; index < length; index++) {
1381 oop o = array->obj_at(index);
1382 if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
1383 ResourceMark rm;
1384 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
1385 p2i(o), o->klass()->external_name(),
1386 p2i(array), array->klass()->external_name());
1387 }
1388 o = mask_dormant_archived_object(o);
1389 writer->write_objectID(o);
1390 }
1391
1392 writer->end_sub_record();
1393 }
1394
1395 #define WRITE_ARRAY(Array, Type, Size, Length) \
1396 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1397
1398 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1399 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1400 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1401 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1402 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1403
1404 int length = calculate_array_max_length(writer, array, header_size);
1405 int type_size = type2aelembytes(type);
1406 u4 length_in_bytes = (u4)length * type_size;
1407 u4 size = header_size + length_in_bytes;
1408
1409 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1410 writer->write_objectID(array);
1411 writer->write_u4(STACK_TRACE_ID);
1412 writer->write_u4(length);
1413 writer->write_u1(type2tag(type));
1414
1415 // nothing to copy
1416 if (length == 0) {
1417 writer->end_sub_record();
1418 return;
1419 }
1420
1421 // If the byte ordering is big endian then we can copy most types directly
1422
1423 switch (type) {
1424 case T_INT : {
1425 if (Endian::is_Java_byte_ordering_different()) {
1426 WRITE_ARRAY(array, int, u4, length);
1427 } else {
1428 writer->write_raw(array->int_at_addr(0), length_in_bytes);
1429 }
1430 break;
1431 }
1432 case T_BYTE : {
1433 writer->write_raw(array->byte_at_addr(0), length_in_bytes);
1434 break;
1435 }
1436 case T_CHAR : {
1437 if (Endian::is_Java_byte_ordering_different()) {
1438 WRITE_ARRAY(array, char, u2, length);
1439 } else {
1440 writer->write_raw(array->char_at_addr(0), length_in_bytes);
1441 }
1442 break;
1443 }
1444 case T_SHORT : {
1445 if (Endian::is_Java_byte_ordering_different()) {
1446 WRITE_ARRAY(array, short, u2, length);
1447 } else {
1448 writer->write_raw(array->short_at_addr(0), length_in_bytes);
1449 }
1450 break;
1451 }
1452 case T_BOOLEAN : {
1453 if (Endian::is_Java_byte_ordering_different()) {
1454 WRITE_ARRAY(array, bool, u1, length);
1455 } else {
1456 writer->write_raw(array->bool_at_addr(0), length_in_bytes);
1457 }
1458 break;
1459 }
1460 case T_LONG : {
1461 if (Endian::is_Java_byte_ordering_different()) {
1462 WRITE_ARRAY(array, long, u8, length);
1463 } else {
1464 writer->write_raw(array->long_at_addr(0), length_in_bytes);
1465 }
1466 break;
1467 }
1468
1469 // handle float/doubles in a special value to ensure than NaNs are
1470 // written correctly. TO DO: Check if we can avoid this on processors that
1471 // use IEEE 754.
1472
1473 case T_FLOAT : {
1474 for (int i = 0; i < length; i++) {
1475 dump_float(writer, array->float_at(i));
1476 }
1477 break;
1478 }
1479 case T_DOUBLE : {
1480 for (int i = 0; i < length; i++) {
1481 dump_double(writer, array->double_at(i));
1482 }
1483 break;
1484 }
1485 default : ShouldNotReachHere();
1486 }
1487
1488 writer->end_sub_record();
1489 }
1490
1491 // create a HPROF_FRAME record of the given Method* and bci
1492 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1493 int frame_serial_num,
1494 int class_serial_num,
1495 Method* m,
1496 int bci) {
1497 int line_number;
1498 if (m->is_native()) {
1499 line_number = -3; // native frame
1500 } else {
1501 line_number = m->line_number_from_bci(bci);
1502 }
1503
1504 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1505 writer->write_id(frame_serial_num); // frame serial number
1506 writer->write_symbolID(m->name()); // method's name
1507 writer->write_symbolID(m->signature()); // method's signature
1508
1509 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1510 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1511 writer->write_u4(class_serial_num); // class serial number
1512 writer->write_u4((u4) line_number); // line number
1513 }
1514
1515
1516 // Support class used to generate HPROF_UTF8 records from the entries in the
1517 // SymbolTable.
1518
1519 class SymbolTableDumper : public SymbolClosure {
1520 private:
1521 AbstractDumpWriter* _writer;
1522 AbstractDumpWriter* writer() const { return _writer; }
1523 public:
1524 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1525 void do_symbol(Symbol** p);
1526 };
1527
1528 void SymbolTableDumper::do_symbol(Symbol** p) {
1529 ResourceMark rm;
1530 Symbol* sym = *p;
1531 int len = sym->utf8_length();
1532 if (len > 0) {
1533 char* s = sym->as_utf8();
1534 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1535 writer()->write_symbolID(sym);
1536 writer()->write_raw(s, len);
1537 }
1538 }
1539
1540 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1541
1542 class JNILocalsDumper : public OopClosure {
1543 private:
1544 AbstractDumpWriter* _writer;
1545 u4 _thread_serial_num;
1546 int _frame_num;
1547 AbstractDumpWriter* writer() const { return _writer; }
1548 public:
1549 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1550 _writer = writer;
1551 _thread_serial_num = thread_serial_num;
1552 _frame_num = -1; // default - empty stack
1553 }
1554 void set_frame_number(int n) { _frame_num = n; }
1555 void do_oop(oop* obj_p);
1556 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1557 };
1558
1559
1560 void JNILocalsDumper::do_oop(oop* obj_p) {
1561 // ignore null handles
1562 oop o = *obj_p;
1563 if (o != NULL) {
1564 u4 size = 1 + sizeof(address) + 4 + 4;
1565 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1566 writer()->write_objectID(o);
1567 writer()->write_u4(_thread_serial_num);
1568 writer()->write_u4((u4)_frame_num);
1569 writer()->end_sub_record();
1570 }
1571 }
1572
1573
1574 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1575
1576 class JNIGlobalsDumper : public OopClosure {
1577 private:
1578 AbstractDumpWriter* _writer;
1579 AbstractDumpWriter* writer() const { return _writer; }
1580
1581 public:
1582 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1583 _writer = writer;
1584 }
1585 void do_oop(oop* obj_p);
1586 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1587 };
1588
1589 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1590 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1591
1592 // ignore these
1593 if (o == NULL) return;
1594 // we ignore global ref to symbols and other internal objects
1595 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1596 u4 size = 1 + 2 * sizeof(address);
1597 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1598 writer()->write_objectID(o);
1599 writer()->write_objectID((oopDesc*)obj_p); // global ref ID
1600 writer()->end_sub_record();
1601 }
1602 };
1603
1604 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1605
1606 class StickyClassDumper : public KlassClosure {
1607 private:
1608 AbstractDumpWriter* _writer;
1609 AbstractDumpWriter* writer() const { return _writer; }
1610 public:
1611 StickyClassDumper(AbstractDumpWriter* writer) {
1612 _writer = writer;
1613 }
1614 void do_klass(Klass* k) {
1615 if (k->is_instance_klass()) {
1616 InstanceKlass* ik = InstanceKlass::cast(k);
1617 u4 size = 1 + sizeof(address);
1618 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1619 writer()->write_classID(ik);
1620 writer()->end_sub_record();
1621 }
1622 }
1623 };
1624
1625 // Large object heap dump support.
1626 // To avoid memory consumption, when dumping large objects such as huge array and
1627 // large objects whose size are larger than LARGE_OBJECT_DUMP_THRESHOLD, the scanned
1628 // partial object/array data will be sent to the backend directly instead of caching
1629 // the whole object/array in the internal buffer.
1630 // The HeapDumpLargeObjectList is used to save the large object when dumper scans
1631 // the heap. The large objects could be added (push) parallelly by multiple dumpers,
1632 // But they will be removed (popped) serially only by the VM thread.
1633 class HeapDumpLargeObjectList : public CHeapObj<mtInternal> {
1634 private:
1635 class HeapDumpLargeObjectListElem : public CHeapObj<mtInternal> {
1636 public:
1637 HeapDumpLargeObjectListElem(oop obj) : _obj(obj), _next(NULL) { }
1638 oop _obj;
1639 HeapDumpLargeObjectListElem* _next;
1640 };
1641
1642 volatile HeapDumpLargeObjectListElem* _head;
1643
1644 public:
1645 HeapDumpLargeObjectList() : _head(NULL) { }
1646
1647 void atomic_push(oop obj) {
1648 assert (obj != NULL, "sanity check");
1649 HeapDumpLargeObjectListElem* entry = new HeapDumpLargeObjectListElem(obj);
1650 if (entry == NULL) {
1651 warning("failed to allocate element for large object list");
1652 return;
1653 }
1654 assert (entry->_obj != NULL, "sanity check");
1655 while (true) {
1656 volatile HeapDumpLargeObjectListElem* old_head = Atomic::load_acquire(&_head);
1657 HeapDumpLargeObjectListElem* new_head = entry;
1658 if (Atomic::cmpxchg(&_head, old_head, new_head) == old_head) {
1659 // successfully push
1660 new_head->_next = (HeapDumpLargeObjectListElem*)old_head;
1661 return;
1662 }
1663 }
1664 }
1665
1666 oop pop() {
1667 if (_head == NULL) {
1668 return NULL;
1669 }
1670 HeapDumpLargeObjectListElem* entry = (HeapDumpLargeObjectListElem*)_head;
1671 _head = _head->_next;
1672 assert (entry != NULL, "illegal larger object list entry");
1673 oop ret = entry->_obj;
1674 delete entry;
1675 assert (ret != NULL, "illegal oop pointer");
1676 return ret;
1677 }
1678
1679 void drain(ObjectClosure* cl) {
1680 while (_head != NULL) {
1681 cl->do_object(pop());
1682 }
1683 }
1684
1685 bool is_empty() {
1686 return _head == NULL;
1687 }
1688
1689 static const size_t LargeObjectSizeThreshold = 1 << 20; // 1 MB
1690 };
1691
1692 class VM_HeapDumper;
1693
1694 // Support class using when iterating over the heap.
1695 class HeapObjectDumper : public ObjectClosure {
1696 private:
1697 AbstractDumpWriter* _writer;
1698 HeapDumpLargeObjectList* _list;
1699
1700 AbstractDumpWriter* writer() { return _writer; }
1701 bool is_large(oop o);
1702 public:
1703 HeapObjectDumper(AbstractDumpWriter* writer, HeapDumpLargeObjectList* list = NULL) {
1704 _writer = writer;
1705 _list = list;
1706 }
1707
1708 // called for each object in the heap
1709 void do_object(oop o);
1710 };
1711
1712 void HeapObjectDumper::do_object(oop o) {
1713 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1714 if (o->klass() == vmClasses::Class_klass()) {
1715 if (!java_lang_Class::is_primitive(o)) {
1716 return;
1717 }
1718 }
1719
1720 if (DumperSupport::mask_dormant_archived_object(o) == NULL) {
1721 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o), o->klass()->external_name());
1722 return;
1723 }
1724
1725 // If large object list exists and it is large object/array,
1726 // add oop into the list and skip scan. VM thread will process it later.
1727 if (_list != NULL && is_large(o)) {
1728 _list->atomic_push(o);
1729 return;
1730 }
1731
1732 if (o->is_instance()) {
1733 // create a HPROF_GC_INSTANCE record for each object
1734 DumperSupport::dump_instance(writer(), o);
1735 } else if (o->is_objArray()) {
1736 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1737 DumperSupport::dump_object_array(writer(), objArrayOop(o));
1738 } else if (o->is_typeArray()) {
1739 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1740 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1741 }
1742 }
1743
1744 bool HeapObjectDumper::is_large(oop o) {
1745 size_t size = 0;
1746 if (o->is_instance()) {
1747 // Use o->size() * 8 as the upper limit of instance size to avoid iterating static fields
1748 size = o->size() * 8;
1749 } else if (o->is_objArray()) {
1750 objArrayOop array = objArrayOop(o);
1751 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1752 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1753 int length = array->length();
1754 int type_size = sizeof(address);
1755 size = (size_t)length * type_size;
1756 } else if (o->is_typeArray()) {
1757 typeArrayOop array = typeArrayOop(o);
1758 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1759 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1760 int length = array->length();
1761 int type_size = type2aelembytes(type);
1762 size = (size_t)length * type_size;
1763 }
1764 return size > HeapDumpLargeObjectList::LargeObjectSizeThreshold;
1765 }
1766
1767 // The dumper controller for parallel heap dump
1768 class DumperController : public CHeapObj<mtInternal> {
1769 private:
1770 bool _started;
1771 Monitor* _lock;
1772 uint _dumper_number;
1773 uint _complete_number;
1774
1775 public:
1776 DumperController(uint number) :
1777 _started(false),
1778 _lock(new (std::nothrow) PaddedMonitor(Mutex::safepoint, "DumperController_lock")),
1779 _dumper_number(number),
1780 _complete_number(0) { }
1781
1782 ~DumperController() { delete _lock; }
1783
1784 void wait_for_start_signal() {
1785 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1786 while (_started == false) {
1787 ml.wait();
1788 }
1789 assert(_started == true, "dumper woke up with wrong state");
1790 }
1791
1792 void start_dump() {
1793 assert (_started == false, "start dump with wrong state");
1794 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1795 _started = true;
1796 ml.notify_all();
1797 }
1798
1799 void dumper_complete() {
1800 assert (_started == true, "dumper complete with wrong state");
1801 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1802 _complete_number++;
1803 ml.notify();
1804 }
1805
1806 void wait_all_dumpers_complete() {
1807 assert (_started == true, "wrong state when wait for dumper complete");
1808 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1809 while (_complete_number != _dumper_number) {
1810 ml.wait();
1811 }
1812 _started = false;
1813 }
1814 };
1815
1816 // The VM operation that performs the heap dump
1817 class VM_HeapDumper : public VM_GC_Operation, public WorkerTask {
1818 private:
1819 static VM_HeapDumper* _global_dumper;
1820 static DumpWriter* _global_writer;
1821 DumpWriter* _local_writer;
1822 JavaThread* _oome_thread;
1823 Method* _oome_constructor;
1824 bool _gc_before_heap_dump;
1825 GrowableArray<Klass*>* _klass_map;
1826 ThreadStackTrace** _stack_traces;
1827 int _num_threads;
1828 // parallel heap dump support
1829 uint _num_dumper_threads;
1830 uint _num_writer_threads;
1831 DumperController* _dumper_controller;
1832 ParallelObjectIterator* _poi;
1833 HeapDumpLargeObjectList* _large_object_list;
1834
1835 // VMDumperType is for thread that dumps both heap and non-heap data.
1836 static const size_t VMDumperType = 0;
1837 static const size_t WriterType = 1;
1838 static const size_t DumperType = 2;
1839 // worker id of VMDumper thread.
1840 static const size_t VMDumperWorkerId = 0;
1841
1842 size_t get_worker_type(uint worker_id) {
1843 assert(_num_writer_threads >= 1, "Must be at least one writer");
1844 // worker id of VMDumper that dump heap and non-heap data
1845 if (worker_id == VMDumperWorkerId) {
1846 return VMDumperType;
1847 }
1848
1849 // worker id of dumper starts from 1, which only dump heap datar
1850 if (worker_id < _num_dumper_threads) {
1851 return DumperType;
1852 }
1853
1854 // worker id of writer starts from _num_dumper_threads
1855 return WriterType;
1856 }
1857
1858 void prepare_parallel_dump(uint num_total) {
1859 assert (_dumper_controller == NULL, "dumper controller must be NULL");
1860 assert (num_total > 0, "active workers number must >= 1");
1861 // Dumper threads number must not be larger than active workers number.
1862 if (num_total < _num_dumper_threads) {
1863 _num_dumper_threads = num_total - 1;
1864 }
1865 // Calculate dumper and writer threads number.
1866 _num_writer_threads = num_total - _num_dumper_threads;
1867 // If dumper threads number is 1, only the VMThread works as a dumper.
1868 // If dumper threads number is equal to active workers, need at lest one worker thread as writer.
1869 if (_num_dumper_threads > 0 && _num_writer_threads == 0) {
1870 _num_writer_threads = 1;
1871 _num_dumper_threads = num_total - _num_writer_threads;
1872 }
1873 // Prepare parallel writer.
1874 if (_num_dumper_threads > 1) {
1875 ParDumpWriter::before_work();
1876 // Number of dumper threads that only iterate heap.
1877 uint _heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */;
1878 _dumper_controller = new (std::nothrow) DumperController(_heap_only_dumper_threads);
1879 }
1880 }
1881
1882 void finish_parallel_dump() {
1883 if (_num_dumper_threads > 1) {
1884 ParDumpWriter::after_work();
1885 }
1886 }
1887
1888 // accessors and setters
1889 static VM_HeapDumper* dumper() { assert(_global_dumper != NULL, "Error"); return _global_dumper; }
1890 static DumpWriter* writer() { assert(_global_writer != NULL, "Error"); return _global_writer; }
1891 void set_global_dumper() {
1892 assert(_global_dumper == NULL, "Error");
1893 _global_dumper = this;
1894 }
1895 void set_global_writer() {
1896 assert(_global_writer == NULL, "Error");
1897 _global_writer = _local_writer;
1898 }
1899 void clear_global_dumper() { _global_dumper = NULL; }
1900 void clear_global_writer() { _global_writer = NULL; }
1901
1902 bool skip_operation() const;
1903
1904 // writes a HPROF_LOAD_CLASS record
1905 static void do_load_class(Klass* k);
1906
1907 // writes a HPROF_GC_CLASS_DUMP record for the given class
1908 static void do_class_dump(Klass* k);
1909
1910 // HPROF_GC_ROOT_THREAD_OBJ records
1911 int do_thread(JavaThread* thread, u4 thread_serial_num);
1912 void do_threads();
1913
1914 void add_class_serial_number(Klass* k, int serial_num) {
1915 _klass_map->at_put_grow(serial_num, k);
1916 }
1917
1918 // HPROF_TRACE and HPROF_FRAME records
1919 void dump_stack_traces();
1920
1921 // large objects
1922 void dump_large_objects(ObjectClosure* writer);
1923
1924 public:
1925 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
1926 VM_GC_Operation(0 /* total collections, dummy, ignored */,
1927 GCCause::_heap_dump /* GC Cause */,
1928 0 /* total full collections, dummy, ignored */,
1929 gc_before_heap_dump),
1930 WorkerTask("dump heap") {
1931 _local_writer = writer;
1932 _gc_before_heap_dump = gc_before_heap_dump;
1933 _klass_map = new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
1934 _stack_traces = NULL;
1935 _num_threads = 0;
1936 _num_dumper_threads = num_dump_threads;
1937 _dumper_controller = NULL;
1938 _poi = NULL;
1939 _large_object_list = new (std::nothrow) HeapDumpLargeObjectList();
1940 if (oome) {
1941 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
1942 // get OutOfMemoryError zero-parameter constructor
1943 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
1944 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
1945 vmSymbols::void_method_signature());
1946 // get thread throwing OOME when generating the heap dump at OOME
1947 _oome_thread = JavaThread::current();
1948 } else {
1949 _oome_thread = NULL;
1950 _oome_constructor = NULL;
1951 }
1952 }
1953
1954 ~VM_HeapDumper() {
1955 if (_stack_traces != NULL) {
1956 for (int i=0; i < _num_threads; i++) {
1957 delete _stack_traces[i];
1958 }
1959 FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces);
1960 }
1961 if (_dumper_controller != NULL) {
1962 delete _dumper_controller;
1963 _dumper_controller = NULL;
1964 }
1965 delete _klass_map;
1966 delete _large_object_list;
1967 }
1968
1969 VMOp_Type type() const { return VMOp_HeapDumper; }
1970 void doit();
1971 void work(uint worker_id);
1972 };
1973
1974 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;
1975 DumpWriter* VM_HeapDumper::_global_writer = NULL;
1976
1977 bool VM_HeapDumper::skip_operation() const {
1978 return false;
1979 }
1980
1981 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
1982 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
1983 writer->finish_dump_segment();
1984
1985 writer->write_u1(HPROF_HEAP_DUMP_END);
1986 writer->write_u4(0);
1987 writer->write_u4(0);
1988 }
1989
1990 // writes a HPROF_LOAD_CLASS record for the class
1991 void VM_HeapDumper::do_load_class(Klass* k) {
1992 static u4 class_serial_num = 0;
1993
1994 // len of HPROF_LOAD_CLASS record
1995 u4 remaining = 2*oopSize + 2*sizeof(u4);
1996
1997 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
1998
1999 // class serial number is just a number
2000 writer()->write_u4(++class_serial_num);
2001
2002 // class ID
2003 writer()->write_classID(k);
2004
2005 // add the Klass* and class serial number pair
2006 dumper()->add_class_serial_number(k, class_serial_num);
2007
2008 writer()->write_u4(STACK_TRACE_ID);
2009
2010 // class name ID
2011 Symbol* name = k->name();
2012 writer()->write_symbolID(name);
2013 }
2014
2015 // writes a HPROF_GC_CLASS_DUMP record for the given class
2016 void VM_HeapDumper::do_class_dump(Klass* k) {
2017 if (k->is_instance_klass()) {
2018 DumperSupport::dump_instance_class(writer(), k);
2019 } else {
2020 DumperSupport::dump_array_class(writer(), k);
2021 }
2022 }
2023
2024 // Walk the stack of the given thread.
2025 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
2026 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
2027 //
2028 // It returns the number of Java frames in this thread stack
2029 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
2030 JNILocalsDumper blk(writer(), thread_serial_num);
2031
2032 oop threadObj = java_thread->threadObj();
2033 assert(threadObj != NULL, "sanity check");
2034
2035 int stack_depth = 0;
2036 if (java_thread->has_last_Java_frame()) {
2037
2038 // vframes are resource allocated
2039 Thread* current_thread = Thread::current();
2040 ResourceMark rm(current_thread);
2041 HandleMark hm(current_thread);
2042
2043 RegisterMap reg_map(java_thread);
2044 frame f = java_thread->last_frame();
2045 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2046 frame* last_entry_frame = NULL;
2047 int extra_frames = 0;
2048
2049 if (java_thread == _oome_thread && _oome_constructor != NULL) {
2050 extra_frames++;
2051 }
2052 while (vf != NULL) {
2053 blk.set_frame_number(stack_depth);
2054 if (vf->is_java_frame()) {
2055
2056 // java frame (interpreted, compiled, ...)
2057 javaVFrame *jvf = javaVFrame::cast(vf);
2058 if (!(jvf->method()->is_native())) {
2059 StackValueCollection* locals = jvf->locals();
2060 for (int slot=0; slot<locals->size(); slot++) {
2061 if (locals->at(slot)->type() == T_OBJECT) {
2062 oop o = locals->obj_at(slot)();
2063
2064 if (o != NULL) {
2065 u4 size = 1 + sizeof(address) + 4 + 4;
2066 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2067 writer()->write_objectID(o);
2068 writer()->write_u4(thread_serial_num);
2069 writer()->write_u4((u4) (stack_depth + extra_frames));
2070 writer()->end_sub_record();
2071 }
2072 }
2073 }
2074 StackValueCollection *exprs = jvf->expressions();
2075 for(int index = 0; index < exprs->size(); index++) {
2076 if (exprs->at(index)->type() == T_OBJECT) {
2077 oop o = exprs->obj_at(index)();
2078 if (o != NULL) {
2079 u4 size = 1 + sizeof(address) + 4 + 4;
2080 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2081 writer()->write_objectID(o);
2082 writer()->write_u4(thread_serial_num);
2083 writer()->write_u4((u4) (stack_depth + extra_frames));
2084 writer()->end_sub_record();
2085 }
2086 }
2087 }
2088 } else {
2089 // native frame
2090 if (stack_depth == 0) {
2091 // JNI locals for the top frame.
2092 java_thread->active_handles()->oops_do(&blk);
2093 } else {
2094 if (last_entry_frame != NULL) {
2095 // JNI locals for the entry frame
2096 assert(last_entry_frame->is_entry_frame(), "checking");
2097 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
2098 }
2099 }
2100 }
2101 // increment only for Java frames
2102 stack_depth++;
2103 last_entry_frame = NULL;
2104
2105 } else {
2106 // externalVFrame - if it's an entry frame then report any JNI locals
2107 // as roots when we find the corresponding native javaVFrame
2108 frame* fr = vf->frame_pointer();
2109 assert(fr != NULL, "sanity check");
2110 if (fr->is_entry_frame()) {
2111 last_entry_frame = fr;
2112 }
2113 }
2114 vf = vf->sender();
2115 }
2116 } else {
2117 // no last java frame but there may be JNI locals
2118 java_thread->active_handles()->oops_do(&blk);
2119 }
2120 return stack_depth;
2121 }
2122
2123
2124 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
2125 // the stack so that locals and JNI locals are dumped.
2126 void VM_HeapDumper::do_threads() {
2127 for (int i=0; i < _num_threads; i++) {
2128 JavaThread* thread = _stack_traces[i]->thread();
2129 oop threadObj = thread->threadObj();
2130 u4 thread_serial_num = i+1;
2131 u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
2132 u4 size = 1 + sizeof(address) + 4 + 4;
2133 writer()->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
2134 writer()->write_objectID(threadObj);
2135 writer()->write_u4(thread_serial_num); // thread number
2136 writer()->write_u4(stack_serial_num); // stack trace serial number
2137 writer()->end_sub_record();
2138 int num_frames = do_thread(thread, thread_serial_num);
2139 assert(num_frames == _stack_traces[i]->get_stack_depth(),
2140 "total number of Java frames not matched");
2141 }
2142 }
2143
2144
2145 // The VM operation that dumps the heap. The dump consists of the following
2146 // records:
2147 //
2148 // HPROF_HEADER
2149 // [HPROF_UTF8]*
2150 // [HPROF_LOAD_CLASS]*
2151 // [[HPROF_FRAME]*|HPROF_TRACE]*
2152 // [HPROF_GC_CLASS_DUMP]*
2153 // [HPROF_HEAP_DUMP_SEGMENT]*
2154 // HPROF_HEAP_DUMP_END
2155 //
2156 // The HPROF_TRACE records represent the stack traces where the heap dump
2157 // is generated and a "dummy trace" record which does not include
2158 // any frames. The dummy trace record is used to be referenced as the
2159 // unknown object alloc site.
2160 //
2161 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2162 // To allow the heap dump be generated in a single pass we remember the position
2163 // of the dump length and fix it up after all sub-records have been written.
2164 // To generate the sub-records we iterate over the heap, writing
2165 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2166 // records as we go. Once that is done we write records for some of the GC
2167 // roots.
2168
2169 void VM_HeapDumper::doit() {
2170
2171 CollectedHeap* ch = Universe::heap();
2172
2173 ch->ensure_parsability(false); // must happen, even if collection does
2174 // not happen (e.g. due to GCLocker)
2175
2176 if (_gc_before_heap_dump) {
2177 if (GCLocker::is_active()) {
2178 warning("GC locker is held; pre-heapdump GC was skipped");
2179 } else {
2180 ch->collect_as_vm_thread(GCCause::_heap_dump);
2181 }
2182 }
2183
2184 // At this point we should be the only dumper active, so
2185 // the following should be safe.
2186 set_global_dumper();
2187 set_global_writer();
2188
2189 WorkerThreads* workers = ch->safepoint_workers();
2190
2191 if (workers == NULL) {
2192 // Use serial dump, set dumper threads and writer threads number to 1.
2193 _num_dumper_threads=1;
2194 _num_writer_threads=1;
2195 work(0);
2196 } else {
2197 prepare_parallel_dump(workers->active_workers());
2198 if (_num_dumper_threads > 1) {
2199 ParallelObjectIterator poi(_num_dumper_threads);
2200 _poi = &poi;
2201 workers->run_task(this);
2202 _poi = NULL;
2203 } else {
2204 workers->run_task(this);
2205 }
2206 finish_parallel_dump();
2207 }
2208
2209 // Now we clear the global variables, so that a future dumper can run.
2210 clear_global_dumper();
2211 clear_global_writer();
2212 }
2213
2214 void VM_HeapDumper::work(uint worker_id) {
2215 if (worker_id != 0) {
2216 if (get_worker_type(worker_id) == WriterType) {
2217 writer()->writer_loop();
2218 return;
2219 }
2220 if (_num_dumper_threads > 1 && get_worker_type(worker_id) == DumperType) {
2221 _dumper_controller->wait_for_start_signal();
2222 }
2223 } else {
2224 // The worker 0 on all non-heap data dumping and part of heap iteration.
2225 // Write the file header - we always use 1.0.2
2226 const char* header = "JAVA PROFILE 1.0.2";
2227
2228 // header is few bytes long - no chance to overflow int
2229 writer()->write_raw(header, strlen(header) + 1); // NUL terminated
2230 writer()->write_u4(oopSize);
2231 // timestamp is current time in ms
2232 writer()->write_u8(os::javaTimeMillis());
2233 // HPROF_UTF8 records
2234 SymbolTableDumper sym_dumper(writer());
2235 SymbolTable::symbols_do(&sym_dumper);
2236
2237 // write HPROF_LOAD_CLASS records
2238 {
2239 LockedClassesDo locked_load_classes(&do_load_class);
2240 ClassLoaderDataGraph::classes_do(&locked_load_classes);
2241 }
2242
2243 // write HPROF_FRAME and HPROF_TRACE records
2244 // this must be called after _klass_map is built when iterating the classes above.
2245 dump_stack_traces();
2246
2247 // Writes HPROF_GC_CLASS_DUMP records
2248 {
2249 LockedClassesDo locked_dump_class(&do_class_dump);
2250 ClassLoaderDataGraph::classes_do(&locked_dump_class);
2251 }
2252
2253 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2254 do_threads();
2255
2256 // HPROF_GC_ROOT_JNI_GLOBAL
2257 JNIGlobalsDumper jni_dumper(writer());
2258 JNIHandles::oops_do(&jni_dumper);
2259 // technically not jni roots, but global roots
2260 // for things like preallocated throwable backtraces
2261 Universe::vm_global()->oops_do(&jni_dumper);
2262 // HPROF_GC_ROOT_STICKY_CLASS
2263 // These should be classes in the NULL class loader data, and not all classes
2264 // if !ClassUnloading
2265 StickyClassDumper class_dumper(writer());
2266 ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper);
2267 }
2268 // writes HPROF_GC_INSTANCE_DUMP records.
2269 // After each sub-record is written check_segment_length will be invoked
2270 // to check if the current segment exceeds a threshold. If so, a new
2271 // segment is started.
2272 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2273 // of the heap dump.
2274 if (_num_dumper_threads <= 1) {
2275 HeapObjectDumper obj_dumper(writer());
2276 Universe::heap()->object_iterate(&obj_dumper);
2277 } else {
2278 assert(get_worker_type(worker_id) == DumperType
2279 || get_worker_type(worker_id) == VMDumperType,
2280 "must be dumper thread to do heap iteration");
2281 if (get_worker_type(worker_id) == VMDumperType) {
2282 // Clear global writer's buffer.
2283 writer()->finish_dump_segment(true);
2284 // Notify dumpers to start heap iteration.
2285 _dumper_controller->start_dump();
2286 }
2287 // Heap iteration.
2288 {
2289 ParDumpWriter pw(writer());
2290 {
2291 HeapObjectDumper obj_dumper(&pw, _large_object_list);
2292 _poi->object_iterate(&obj_dumper, worker_id);
2293 }
2294
2295 if (get_worker_type(worker_id) == VMDumperType) {
2296 _dumper_controller->wait_all_dumpers_complete();
2297 // clear internal buffer;
2298 pw.finish_dump_segment(true);
2299 // refresh the global_writer's buffer and position;
2300 writer()->refresh();
2301 } else {
2302 pw.finish_dump_segment(true);
2303 _dumper_controller->dumper_complete();
2304 return;
2305 }
2306 }
2307 }
2308
2309 assert(get_worker_type(worker_id) == VMDumperType, "Heap dumper must be VMDumper");
2310 // Use writer() rather than ParDumpWriter to avoid memory consumption.
2311 HeapObjectDumper obj_dumper(writer());
2312 dump_large_objects(&obj_dumper);
2313 // Writes the HPROF_HEAP_DUMP_END record.
2314 DumperSupport::end_of_dump(writer());
2315 // We are done with writing. Release the worker threads.
2316 writer()->deactivate();
2317 }
2318
2319 void VM_HeapDumper::dump_stack_traces() {
2320 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2321 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
2322 writer()->write_u4((u4) STACK_TRACE_ID);
2323 writer()->write_u4(0); // thread number
2324 writer()->write_u4(0); // frame count
2325
2326 _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);
2327 int frame_serial_num = 0;
2328 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
2329 oop threadObj = thread->threadObj();
2330 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
2331 // dump thread stack trace
2332 Thread* current_thread = Thread::current();
2333 ResourceMark rm(current_thread);
2334 HandleMark hm(current_thread);
2335
2336 ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
2337 stack_trace->dump_stack_at_safepoint(-1, /* ObjectMonitorsHashtable is not needed here */ nullptr);
2338 _stack_traces[_num_threads++] = stack_trace;
2339
2340 // write HPROF_FRAME records for this thread's stack trace
2341 int depth = stack_trace->get_stack_depth();
2342 int thread_frame_start = frame_serial_num;
2343 int extra_frames = 0;
2344 // write fake frame that makes it look like the thread, which caused OOME,
2345 // is in the OutOfMemoryError zero-parameter constructor
2346 if (thread == _oome_thread && _oome_constructor != NULL) {
2347 int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());
2348 // the class serial number starts from 1
2349 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
2350 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
2351 _oome_constructor, 0);
2352 extra_frames++;
2353 }
2354 for (int j=0; j < depth; j++) {
2355 StackFrameInfo* frame = stack_trace->stack_frame_at(j);
2356 Method* m = frame->method();
2357 int class_serial_num = _klass_map->find(m->method_holder());
2358 // the class serial number starts from 1
2359 assert(class_serial_num > 0, "class not found");
2360 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
2361 }
2362 depth += extra_frames;
2363
2364 // write HPROF_TRACE record for one thread
2365 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
2366 int stack_serial_num = _num_threads + STACK_TRACE_ID;
2367 writer()->write_u4(stack_serial_num); // stack trace serial number
2368 writer()->write_u4((u4) _num_threads); // thread serial number
2369 writer()->write_u4(depth); // frame count
2370 for (int j=1; j <= depth; j++) {
2371 writer()->write_id(thread_frame_start + j);
2372 }
2373 }
2374 }
2375 }
2376
2377 // dump the large objects.
2378 void VM_HeapDumper::dump_large_objects(ObjectClosure* cl) {
2379 _large_object_list->drain(cl);
2380 }
2381
2382 // dump the heap to given path.
2383 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2384 assert(path != NULL && strlen(path) > 0, "path missing");
2385
2386 // print message in interactive case
2387 if (out != NULL) {
2388 out->print_cr("Dumping heap to %s ...", path);
2389 timer()->start();
2390 }
2391 // create JFR event
2392 EventHeapDump event;
2393
2394 AbstractCompressor* compressor = NULL;
2395
2396 if (compression > 0) {
2397 compressor = new (std::nothrow) GZipCompressor(compression);
2398
2399 if (compressor == NULL) {
2400 set_error("Could not allocate gzip compressor");
2401 return -1;
2402 }
2403 }
2404
2405 DumpWriter writer(new (std::nothrow) FileWriter(path, overwrite), compressor);
2406
2407 if (writer.error() != NULL) {
2408 set_error(writer.error());
2409 if (out != NULL) {
2410 out->print_cr("Unable to create %s: %s", path,
2411 (error() != NULL) ? error() : "reason unknown");
2412 }
2413 return -1;
2414 }
2415
2416 // generate the dump
2417 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2418 if (Thread::current()->is_VM_thread()) {
2419 assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
2420 dumper.doit();
2421 } else {
2422 VMThread::execute(&dumper);
2423 }
2424
2425 // record any error that the writer may have encountered
2426 set_error(writer.error());
2427
2428 // emit JFR event
2429 if (error() == NULL) {
2430 event.set_destination(path);
2431 event.set_gcBeforeDump(_gc_before_heap_dump);
2432 event.set_size(writer.bytes_written());
2433 event.set_onOutOfMemoryError(_oome);
2434 event.commit();
2435 }
2436
2437 // print message in interactive case
2438 if (out != NULL) {
2439 timer()->stop();
2440 if (error() == NULL) {
2441 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2442 writer.bytes_written(), timer()->seconds());
2443 } else {
2444 out->print_cr("Dump file is incomplete: %s", writer.error());
2445 }
2446 }
2447
2448 return (writer.error() == NULL) ? 0 : -1;
2449 }
2450
2451 // stop timer (if still active), and free any error string we might be holding
2452 HeapDumper::~HeapDumper() {
2453 if (timer()->is_active()) {
2454 timer()->stop();
2455 }
2456 set_error(NULL);
2457 }
2458
2459
2460 // returns the error string (resource allocated), or NULL
2461 char* HeapDumper::error_as_C_string() const {
2462 if (error() != NULL) {
2463 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2464 strcpy(str, error());
2465 return str;
2466 } else {
2467 return NULL;
2468 }
2469 }
2470
2471 // set the error string
2472 void HeapDumper::set_error(char const* error) {
2473 if (_error != NULL) {
2474 os::free(_error);
2475 }
2476 if (error == NULL) {
2477 _error = NULL;
2478 } else {
2479 _error = os::strdup(error);
2480 assert(_error != NULL, "allocation failure");
2481 }
2482 }
2483
2484 // Called by out-of-memory error reporting by a single Java thread
2485 // outside of a JVM safepoint
2486 void HeapDumper::dump_heap_from_oome() {
2487 HeapDumper::dump_heap(true);
2488 }
2489
2490 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2491 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2492 // callers are strictly serialized and guaranteed not to interfere below. For more
2493 // general use, however, this method will need modification to prevent
2494 // inteference when updating the static variables base_path and dump_file_seq below.
2495 void HeapDumper::dump_heap() {
2496 HeapDumper::dump_heap(false);
2497 }
2498
2499 void HeapDumper::dump_heap(bool oome) {
2500 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2501 static uint dump_file_seq = 0;
2502 char* my_path;
2503 const int max_digit_chars = 20;
2504
2505 const char* dump_file_name = "java_pid";
2506 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
2507
2508 // The dump file defaults to java_pid<pid>.hprof in the current working
2509 // directory. HeapDumpPath=<file> can be used to specify an alternative
2510 // dump file name or a directory where dump file is created.
2511 if (dump_file_seq == 0) { // first time in, we initialize base_path
2512 // Calculate potentially longest base path and check if we have enough
2513 // allocated statically.
2514 const size_t total_length =
2515 (HeapDumpPath == NULL ? 0 : strlen(HeapDumpPath)) +
2516 strlen(os::file_separator()) + max_digit_chars +
2517 strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2518 if (total_length > sizeof(base_path)) {
2519 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2520 return;
2521 }
2522
2523 bool use_default_filename = true;
2524 if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {
2525 // HeapDumpPath=<file> not specified
2526 } else {
2527 strcpy(base_path, HeapDumpPath);
2528 // check if the path is a directory (must exist)
2529 DIR* dir = os::opendir(base_path);
2530 if (dir == NULL) {
2531 use_default_filename = false;
2532 } else {
2533 // HeapDumpPath specified a directory. We append a file separator
2534 // (if needed).
2535 os::closedir(dir);
2536 size_t fs_len = strlen(os::file_separator());
2537 if (strlen(base_path) >= fs_len) {
2538 char* end = base_path;
2539 end += (strlen(base_path) - fs_len);
2540 if (strcmp(end, os::file_separator()) != 0) {
2541 strcat(base_path, os::file_separator());
2542 }
2543 }
2544 }
2545 }
2546 // If HeapDumpPath wasn't a file name then we append the default name
2547 if (use_default_filename) {
2548 const size_t dlen = strlen(base_path); // if heap dump dir specified
2549 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2550 dump_file_name, os::current_process_id(), dump_file_ext);
2551 }
2552 const size_t len = strlen(base_path) + 1;
2553 my_path = (char*)os::malloc(len, mtInternal);
2554 if (my_path == NULL) {
2555 warning("Cannot create heap dump file. Out of system memory.");
2556 return;
2557 }
2558 strncpy(my_path, base_path, len);
2559 } else {
2560 // Append a sequence number id for dumps following the first
2561 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2562 my_path = (char*)os::malloc(len, mtInternal);
2563 if (my_path == NULL) {
2564 warning("Cannot create heap dump file. Out of system memory.");
2565 return;
2566 }
2567 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2568 }
2569 dump_file_seq++; // increment seq number for next time we dump
2570
2571 HeapDumper dumper(false /* no GC before heap dump */,
2572 oome /* pass along out-of-memory-error flag */);
2573 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2574 os::free(my_path);
2575 }