1 /*
2 * Copyright (c) 2005, 2021, 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/workgroup.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/vmThread.hpp"
55 #include "runtime/vmOperations.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. For example, on
72 * Solaris and Win32, the size is 4.
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 typedef enum {
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 } hprofTag;
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(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 public:
414 AbstractDumpWriter() :
415 _buffer(NULL),
416 _size(io_buffer_max_size),
417 _pos(0),
418 _in_dump_segment(false) { }
419
420 // total number of bytes written to the disk
421 virtual julong bytes_written() const = 0;
422 virtual char const* error() const = 0;
423
424 size_t position() const { return _pos; }
425 // writer functions
426 virtual void write_raw(void* s, size_t len);
427 void write_u1(u1 x);
428 void write_u2(u2 x);
429 void write_u4(u4 x);
430 void write_u8(u8 x);
431 void write_objectID(oop o);
432 void write_symbolID(Symbol* o);
433 void write_classID(Klass* k);
434 void write_id(u4 x);
435
436 // Start a new sub-record. Starts a new heap dump segment if needed.
437 void start_sub_record(u1 tag, u4 len);
438 // Ends the current sub-record.
439 void end_sub_record();
440 // Finishes the current dump segment if not already finished.
441 void finish_dump_segment(bool force_flush = false);
442 // Refresh to get new buffer
443 void refresh() {
444 assert (_in_dump_segment ==false, "Sanity check");
445 _buffer = NULL;
446 _size = io_buffer_max_size;
447 _pos = 0;
448 // Force flush to guarantee data from parallel dumper are written.
449 flush(true);
450 }
451 // Called when finished to release the threads.
452 virtual void deactivate() = 0;
453 };
454
455 void AbstractDumpWriter::write_fast(void* s, size_t len) {
456 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
457 assert(buffer_size() - position() >= len, "Must fit");
458 debug_only(_sub_record_left -= len);
459 memcpy(buffer() + position(), s, len);
460 set_position(position() + len);
461 }
462
463 bool AbstractDumpWriter::can_write_fast(size_t len) {
464 return buffer_size() - position() >= len;
465 }
466
467 // write raw bytes
468 void AbstractDumpWriter::write_raw(void* s, size_t len) {
469 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
470 debug_only(_sub_record_left -= len);
471
472 // flush buffer to make room.
473 while (len > buffer_size() - position()) {
474 assert(!_in_dump_segment || _is_huge_sub_record,
475 "Cannot overflow in non-huge sub-record.");
476 size_t to_write = buffer_size() - position();
477 memcpy(buffer() + position(), s, to_write);
478 s = (void*) ((char*) s + to_write);
479 len -= to_write;
480 set_position(position() + to_write);
481 flush();
482 }
483
484 memcpy(buffer() + position(), s, len);
485 set_position(position() + len);
486 }
487
488 // Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
489 #define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
490 else write_raw((p), (len)); } while (0)
491
492 void AbstractDumpWriter::write_u1(u1 x) {
493 WRITE_KNOWN_TYPE((void*) &x, 1);
494 }
495
496 void AbstractDumpWriter::write_u2(u2 x) {
497 u2 v;
498 Bytes::put_Java_u2((address)&v, x);
499 WRITE_KNOWN_TYPE((void*)&v, 2);
500 }
501
502 void AbstractDumpWriter::write_u4(u4 x) {
503 u4 v;
504 Bytes::put_Java_u4((address)&v, x);
505 WRITE_KNOWN_TYPE((void*)&v, 4);
506 }
507
508 void AbstractDumpWriter::write_u8(u8 x) {
509 u8 v;
510 Bytes::put_Java_u8((address)&v, x);
511 WRITE_KNOWN_TYPE((void*)&v, 8);
512 }
513
514 void AbstractDumpWriter::write_objectID(oop o) {
515 address a = cast_from_oop<address>(o);
516 #ifdef _LP64
517 write_u8((u8)a);
518 #else
519 write_u4((u4)a);
520 #endif
521 }
522
523 void AbstractDumpWriter::write_symbolID(Symbol* s) {
524 address a = (address)((uintptr_t)s);
525 #ifdef _LP64
526 write_u8((u8)a);
527 #else
528 write_u4((u4)a);
529 #endif
530 }
531
532 void AbstractDumpWriter::write_id(u4 x) {
533 #ifdef _LP64
534 write_u8((u8) x);
535 #else
536 write_u4(x);
537 #endif
538 }
539
540 // We use java mirror as the class ID
541 void AbstractDumpWriter::write_classID(Klass* k) {
542 write_objectID(k->java_mirror());
543 }
544
545 void AbstractDumpWriter::finish_dump_segment(bool force_flush) {
546 if (_in_dump_segment) {
547 assert(_sub_record_left == 0, "Last sub-record not written completely");
548 assert(_sub_record_ended, "sub-record must have ended");
549
550 // Fix up the dump segment length if we haven't written a huge sub-record last
551 // (in which case the segment length was already set to the correct value initially).
552 if (!_is_huge_sub_record) {
553 assert(position() > dump_segment_header_size, "Dump segment should have some content");
554 Bytes::put_Java_u4((address) (buffer() + 5),
555 (u4) (position() - dump_segment_header_size));
556 } else {
557 // Finish process huge sub record
558 // Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
559 _is_huge_sub_record = false;
560 }
561
562 _in_dump_segment = false;
563 flush(force_flush);
564 }
565 }
566
567 void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
568 if (!_in_dump_segment) {
569 if (position() > 0) {
570 flush();
571 }
572
573 assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
574
575 write_u1(HPROF_HEAP_DUMP_SEGMENT);
576 write_u4(0); // timestamp
577 // Will be fixed up later if we add more sub-records. If this is a huge sub-record,
578 // this is already the correct length, since we don't add more sub-records.
579 write_u4(len);
580 assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsitent size!");
581 _in_dump_segment = true;
582 _is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
583 } else if (_is_huge_sub_record || (len > buffer_size() - position())) {
584 // This object will not fit in completely or the last sub-record was huge.
585 // Finish the current segement and try again.
586 finish_dump_segment();
587 start_sub_record(tag, len);
588
589 return;
590 }
591
592 debug_only(_sub_record_left = len);
593 debug_only(_sub_record_ended = false);
594
595 write_u1(tag);
596 }
597
598 void AbstractDumpWriter::end_sub_record() {
599 assert(_in_dump_segment, "must be in dump segment");
600 assert(_sub_record_left == 0, "sub-record not written completely");
601 assert(!_sub_record_ended, "Must not have ended yet");
602 debug_only(_sub_record_ended = true);
603 }
604
605 // Supports I/O operations for a dump
606
607 class DumpWriter : public AbstractDumpWriter {
608 private:
609 CompressionBackend _backend; // Does the actual writing.
610 protected:
611 virtual void flush(bool force = false);
612
613 public:
614 // Takes ownership of the writer and compressor.
615 DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor);
616
617 // total number of bytes written to the disk
618 virtual julong bytes_written() const { return (julong) _backend.get_written(); }
619
620 virtual char const* error() const { return _backend.error(); }
621
622 // Called by threads used for parallel writing.
623 void writer_loop() { _backend.thread_loop(); }
624 // Called when finish to release the threads.
625 virtual void deactivate() { flush(); _backend.deactivate(); }
626 // Get the backend pointer, used by parallel dump writer.
627 CompressionBackend* backend_ptr() { return &_backend; }
628
629 };
630
631 // Check for error after constructing the object and destroy it in case of an error.
632 DumpWriter::DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor) :
633 AbstractDumpWriter(),
634 _backend(writer, compressor, io_buffer_max_size, io_buffer_max_waste) {
635 flush();
636 }
637
638 // flush any buffered bytes to the file
639 void DumpWriter::flush(bool force) {
640 _backend.get_new_buffer(&_buffer, &_pos, &_size, force);
641 }
642
643 // Buffer queue used for parallel dump.
644 struct ParWriterBufferQueueElem {
645 char* _buffer;
646 size_t _used;
647 ParWriterBufferQueueElem* _next;
648 };
649
650 class ParWriterBufferQueue : public CHeapObj<mtInternal> {
651 private:
652 ParWriterBufferQueueElem* _head;
653 ParWriterBufferQueueElem* _tail;
654 uint _length;
655 public:
656 ParWriterBufferQueue() : _head(NULL), _tail(NULL), _length(0) { }
657
658 void enqueue(ParWriterBufferQueueElem* entry) {
659 if (_head == NULL) {
660 assert(is_empty() && _tail == NULL, "Sanity check");
661 _head = _tail = entry;
662 } else {
663 assert ((_tail->_next == NULL && _tail->_buffer != NULL), "Buffer queue is polluted");
664 _tail->_next = entry;
665 _tail = entry;
666 }
667 _length++;
668 assert(_tail->_next == NULL, "Bufer queue is polluted");
669 }
670
671 ParWriterBufferQueueElem* dequeue() {
672 if (_head == NULL) return NULL;
673 ParWriterBufferQueueElem* entry = _head;
674 assert (entry->_buffer != NULL, "polluted buffer in writer list");
675 _head = entry->_next;
676 if (_head == NULL) {
677 _tail = NULL;
678 }
679 entry->_next = NULL;
680 _length--;
681 return entry;
682 }
683
684 bool is_empty() {
685 return _length == 0;
686 }
687
688 uint length() { return _length; }
689 };
690
691 // Support parallel heap dump.
692 class ParDumpWriter : public AbstractDumpWriter {
693 private:
694 // Lock used to guarantee the integrity of multiple buffers writing.
695 static Monitor* _lock;
696 // Pointer of backend from global DumpWriter.
697 CompressionBackend* _backend_ptr;
698 char const * _err;
699 ParWriterBufferQueue* _buffer_queue;
700 size_t _internal_buffer_used;
701 char* _buffer_base;
702 bool _split_data;
703 static const uint BackendFlushThreshold = 2;
704 protected:
705 virtual void flush(bool force = false) {
706 assert(_pos != 0, "must not be zero");
707 if (_pos != 0) {
708 refresh_buffer();
709 }
710
711 if (_split_data || _is_huge_sub_record) {
712 return;
713 }
714
715 if (should_flush_buf_list(force)) {
716 assert(!_in_dump_segment && !_split_data && !_is_huge_sub_record, "incomplete data send to backend!\n");
717 flush_to_backend(force);
718 }
719 }
720
721 public:
722 // Check for error after constructing the object and destroy it in case of an error.
723 ParDumpWriter(DumpWriter* dw) :
724 AbstractDumpWriter(),
725 _backend_ptr(dw->backend_ptr()),
726 _buffer_queue((new (std::nothrow) ParWriterBufferQueue())),
727 _buffer_base(NULL),
728 _split_data(false) {
729 // prepare internal buffer
730 allocate_internal_buffer();
731 }
732
733 ~ParDumpWriter() {
734 assert(_buffer_queue != NULL, "Sanity check");
735 assert((_internal_buffer_used == 0) && (_buffer_queue->is_empty()),
736 "All data must be send to backend");
737 if (_buffer_base != NULL) {
738 os::free(_buffer_base);
739 _buffer_base = NULL;
740 }
741 delete _buffer_queue;
742 _buffer_queue = NULL;
743 }
744
745 // total number of bytes written to the disk
746 virtual julong bytes_written() const { return (julong) _backend_ptr->get_written(); }
747 virtual char const* error() const { return _err == NULL ? _backend_ptr->error() : _err; }
748
749 static void before_work() {
750 assert(_lock == NULL, "ParDumpWriter lock must be initialized only once");
751 _lock = new (std::nothrow) PaddedMonitor(Mutex::nonleaf, "ParallelHProfWriter_lock", Mutex::_safepoint_check_always);
752 }
753
754 static void after_work() {
755 assert(_lock != NULL, "ParDumpWriter lock is not initialized");
756 delete _lock;
757 _lock = NULL;
758 }
759
760 // write raw bytes
761 virtual void write_raw(void* s, size_t len) {
762 assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
763 debug_only(_sub_record_left -= len);
764 assert(!_split_data, "Invalid split data");
765 _split_data = true;
766 // flush buffer to make room.
767 while (len > buffer_size() - position()) {
768 assert(!_in_dump_segment || _is_huge_sub_record,
769 "Cannot overflow in non-huge sub-record.");
770 size_t to_write = buffer_size() - position();
771 memcpy(buffer() + position(), s, to_write);
772 s = (void*) ((char*) s + to_write);
773 len -= to_write;
774 set_position(position() + to_write);
775 flush();
776 }
777 _split_data = false;
778 memcpy(buffer() + position(), s, len);
779 set_position(position() + len);
780 }
781
782 virtual void deactivate() { flush(true); _backend_ptr->deactivate(); }
783
784 private:
785 void allocate_internal_buffer() {
786 assert(_buffer_queue != NULL, "Internal buffer queue is not ready when allocate internal buffer");
787 assert(_buffer == NULL && _buffer_base == NULL, "current buffer must be NULL before allocate");
788 _buffer_base = _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
789 if (_buffer == NULL) {
790 set_error("Could not allocate buffer for writer");
791 return;
792 }
793 _pos = 0;
794 _internal_buffer_used = 0;
795 _size = io_buffer_max_size;
796 }
797
798 void set_error(char const* new_error) {
799 if ((new_error != NULL) && (_err == NULL)) {
800 _err = new_error;
801 }
802 }
803
804 // Add buffer to internal list
805 void refresh_buffer() {
806 size_t expected_total = _internal_buffer_used + _pos;
807 if (expected_total < io_buffer_max_size - io_buffer_max_waste) {
808 // reuse current buffer.
809 _internal_buffer_used = expected_total;
810 assert(_size - _pos == io_buffer_max_size - expected_total, "illegal resize of buffer");
811 _size -= _pos;
812 _buffer += _pos;
813 _pos = 0;
814
815 return;
816 }
817 // It is not possible here that expected_total is larger than io_buffer_max_size because
818 // of limitation in write_xxx().
819 assert(expected_total <= io_buffer_max_size, "buffer overflow");
820 assert(_buffer - _buffer_base <= io_buffer_max_size, "internal buffer overflow");
821 ParWriterBufferQueueElem* entry =
822 (ParWriterBufferQueueElem*)os::malloc(sizeof(ParWriterBufferQueueElem), mtInternal);
823 if (entry == NULL) {
824 set_error("Heap dumper can allocate memory");
825 return;
826 }
827 entry->_buffer = _buffer_base;
828 entry->_used = expected_total;
829 entry->_next = NULL;
830 // add to internal buffer queue
831 _buffer_queue->enqueue(entry);
832 _buffer_base =_buffer = NULL;
833 allocate_internal_buffer();
834 }
835
836 void reclaim_entry(ParWriterBufferQueueElem* entry) {
837 assert(entry != NULL && entry->_buffer != NULL, "Invalid entry to reclaim");
838 os::free(entry->_buffer);
839 entry->_buffer = NULL;
840 os::free(entry);
841 }
842
843 void flush_buffer(char* buffer, size_t used) {
844 assert(_lock->owner() == Thread::current(), "flush buffer must hold lock");
845 size_t max = io_buffer_max_size;
846 // get_new_buffer
847 _backend_ptr->flush_external_buffer(buffer, used, max);
848 }
849
850 bool should_flush_buf_list(bool force) {
851 return force || _buffer_queue->length() > BackendFlushThreshold;
852 }
853
854 void flush_to_backend(bool force) {
855 // Guarantee there is only one writer updating the backend buffers.
856 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
857 while (!_buffer_queue->is_empty()) {
858 ParWriterBufferQueueElem* entry = _buffer_queue->dequeue();
859 flush_buffer(entry->_buffer, entry->_used);
860 // Delete buffer and entry.
861 reclaim_entry(entry);
862 entry = NULL;
863 }
864 assert(_pos == 0, "available buffer must be empty before flush");
865 // Flush internal buffer.
866 if (_internal_buffer_used > 0) {
867 flush_buffer(_buffer_base, _internal_buffer_used);
868 os::free(_buffer_base);
869 _pos = 0;
870 _internal_buffer_used = 0;
871 _buffer_base = _buffer = NULL;
872 // Allocate internal buffer for future use.
873 allocate_internal_buffer();
874 }
875 }
876 };
877
878 Monitor* ParDumpWriter::_lock = NULL;
879
880 // Support class with a collection of functions used when dumping the heap
881
882 class DumperSupport : AllStatic {
883 public:
884
885 // write a header of the given type
886 static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
887
888 // returns hprof tag for the given type signature
889 static hprofTag sig2tag(Symbol* sig);
890 // returns hprof tag for the given basic type
891 static hprofTag type2tag(BasicType type);
892 // Returns the size of the data to write.
893 static u4 sig2size(Symbol* sig);
894
895 // returns the size of the instance of the given class
896 static u4 instance_size(Klass* k);
897
898 // dump a jfloat
899 static void dump_float(AbstractDumpWriter* writer, jfloat f);
900 // dump a jdouble
901 static void dump_double(AbstractDumpWriter* writer, jdouble d);
902 // dumps the raw value of the given field
903 static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
904 // returns the size of the static fields; also counts the static fields
905 static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
906 // dumps static fields of the given class
907 static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
908 // dump the raw values of the instance fields of the given object
909 static void dump_instance_fields(AbstractDumpWriter* writer, oop o);
910 // get the count of the instance fields for a given class
911 static u2 get_instance_fields_count(InstanceKlass* ik);
912 // dumps the definition of the instance fields for a given class
913 static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
914 // creates HPROF_GC_INSTANCE_DUMP record for the given object
915 static void dump_instance(AbstractDumpWriter* writer, oop o);
916 // creates HPROF_GC_CLASS_DUMP record for the given class and each of its
917 // array classes
918 static void dump_class_and_array_classes(AbstractDumpWriter* writer, Klass* k);
919 // creates HPROF_GC_CLASS_DUMP record for a given primitive array
920 // class (and each multi-dimensional array class too)
921 static void dump_basic_type_array_class(AbstractDumpWriter* writer, Klass* k);
922
923 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
924 static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
925 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
926 static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
927 // create HPROF_FRAME record for the given method and bci
928 static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
929
930 // check if we need to truncate an array
931 static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
932
933 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
934 static void end_of_dump(AbstractDumpWriter* writer);
935
936 static oop mask_dormant_archived_object(oop o) {
937 if (o != NULL && o->klass()->java_mirror() == NULL) {
938 // Ignore this object since the corresponding java mirror is not loaded.
939 // Might be a dormant archive object.
940 return NULL;
941 } else {
942 return o;
943 }
944 }
945 };
946
947 // write a header of the given type
948 void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
949 writer->write_u1((u1)tag);
950 writer->write_u4(0); // current ticks
951 writer->write_u4(len);
952 }
953
954 // returns hprof tag for the given type signature
955 hprofTag DumperSupport::sig2tag(Symbol* sig) {
956 switch (sig->char_at(0)) {
957 case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
958 case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
959 case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
960 case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
961 case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
962 case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
963 case JVM_SIGNATURE_INT : return HPROF_INT;
964 case JVM_SIGNATURE_LONG : return HPROF_LONG;
965 case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
966 case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
967 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
968 }
969 }
970
971 hprofTag DumperSupport::type2tag(BasicType type) {
972 switch (type) {
973 case T_BYTE : return HPROF_BYTE;
974 case T_CHAR : return HPROF_CHAR;
975 case T_FLOAT : return HPROF_FLOAT;
976 case T_DOUBLE : return HPROF_DOUBLE;
977 case T_INT : return HPROF_INT;
978 case T_LONG : return HPROF_LONG;
979 case T_SHORT : return HPROF_SHORT;
980 case T_BOOLEAN : return HPROF_BOOLEAN;
981 default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
982 }
983 }
984
985 u4 DumperSupport::sig2size(Symbol* sig) {
986 switch (sig->char_at(0)) {
987 case JVM_SIGNATURE_CLASS:
988 case JVM_SIGNATURE_ARRAY: return sizeof(address);
989 case JVM_SIGNATURE_BOOLEAN:
990 case JVM_SIGNATURE_BYTE: return 1;
991 case JVM_SIGNATURE_SHORT:
992 case JVM_SIGNATURE_CHAR: return 2;
993 case JVM_SIGNATURE_INT:
994 case JVM_SIGNATURE_FLOAT: return 4;
995 case JVM_SIGNATURE_LONG:
996 case JVM_SIGNATURE_DOUBLE: return 8;
997 default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
998 }
999 }
1000
1001 // dump a jfloat
1002 void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
1003 if (g_isnan(f)) {
1004 writer->write_u4(0x7fc00000); // collapsing NaNs
1005 } else {
1006 union {
1007 int i;
1008 float f;
1009 } u;
1010 u.f = (float)f;
1011 writer->write_u4((u4)u.i);
1012 }
1013 }
1014
1015 // dump a jdouble
1016 void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
1017 union {
1018 jlong l;
1019 double d;
1020 } u;
1021 if (g_isnan(d)) { // collapsing NaNs
1022 u.l = (jlong)(0x7ff80000);
1023 u.l = (u.l << 32);
1024 } else {
1025 u.d = (double)d;
1026 }
1027 writer->write_u8((u8)u.l);
1028 }
1029
1030 // dumps the raw value of the given field
1031 void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
1032 switch (type) {
1033 case JVM_SIGNATURE_CLASS :
1034 case JVM_SIGNATURE_ARRAY : {
1035 oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
1036 if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
1037 ResourceMark rm;
1038 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
1039 p2i(o), o->klass()->external_name(),
1040 p2i(obj), obj->klass()->external_name());
1041 }
1042 o = mask_dormant_archived_object(o);
1043 assert(oopDesc::is_oop_or_null(o), "Expected an oop or NULL at " PTR_FORMAT, p2i(o));
1044 writer->write_objectID(o);
1045 break;
1046 }
1047 case JVM_SIGNATURE_BYTE : {
1048 jbyte b = obj->byte_field(offset);
1049 writer->write_u1((u1)b);
1050 break;
1051 }
1052 case JVM_SIGNATURE_CHAR : {
1053 jchar c = obj->char_field(offset);
1054 writer->write_u2((u2)c);
1055 break;
1056 }
1057 case JVM_SIGNATURE_SHORT : {
1058 jshort s = obj->short_field(offset);
1059 writer->write_u2((u2)s);
1060 break;
1061 }
1062 case JVM_SIGNATURE_FLOAT : {
1063 jfloat f = obj->float_field(offset);
1064 dump_float(writer, f);
1065 break;
1066 }
1067 case JVM_SIGNATURE_DOUBLE : {
1068 jdouble d = obj->double_field(offset);
1069 dump_double(writer, d);
1070 break;
1071 }
1072 case JVM_SIGNATURE_INT : {
1073 jint i = obj->int_field(offset);
1074 writer->write_u4((u4)i);
1075 break;
1076 }
1077 case JVM_SIGNATURE_LONG : {
1078 jlong l = obj->long_field(offset);
1079 writer->write_u8((u8)l);
1080 break;
1081 }
1082 case JVM_SIGNATURE_BOOLEAN : {
1083 jboolean b = obj->bool_field(offset);
1084 writer->write_u1((u1)b);
1085 break;
1086 }
1087 default : {
1088 ShouldNotReachHere();
1089 break;
1090 }
1091 }
1092 }
1093
1094 // returns the size of the instance of the given class
1095 u4 DumperSupport::instance_size(Klass* k) {
1096 InstanceKlass* ik = InstanceKlass::cast(k);
1097 u4 size = 0;
1098
1099 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
1100 if (!fld.access_flags().is_static()) {
1101 size += sig2size(fld.signature());
1102 }
1103 }
1104 return size;
1105 }
1106
1107 u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
1108 field_count = 0;
1109 u4 size = 0;
1110
1111 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
1112 if (fldc.access_flags().is_static()) {
1113 field_count++;
1114 size += sig2size(fldc.signature());
1115 }
1116 }
1117
1118 // Add in resolved_references which is referenced by the cpCache
1119 // The resolved_references is an array per InstanceKlass holding the
1120 // strings and other oops resolved from the constant pool.
1121 oop resolved_references = ik->constants()->resolved_references_or_null();
1122 if (resolved_references != NULL) {
1123 field_count++;
1124 size += sizeof(address);
1125
1126 // Add in the resolved_references of the used previous versions of the class
1127 // in the case of RedefineClasses
1128 InstanceKlass* prev = ik->previous_versions();
1129 while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
1130 field_count++;
1131 size += sizeof(address);
1132 prev = prev->previous_versions();
1133 }
1134 }
1135
1136 // Also provide a pointer to the init_lock if present, so there aren't unreferenced int[0]
1137 // arrays.
1138 oop init_lock = ik->init_lock();
1139 if (init_lock != NULL) {
1140 field_count++;
1141 size += sizeof(address);
1142 }
1143
1144 // We write the value itself plus a name and a one byte type tag per field.
1145 return size + field_count * (sizeof(address) + 1);
1146 }
1147
1148 // dumps static fields of the given class
1149 void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
1150 InstanceKlass* ik = InstanceKlass::cast(k);
1151
1152 // dump the field descriptors and raw values
1153 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
1154 if (fld.access_flags().is_static()) {
1155 Symbol* sig = fld.signature();
1156
1157 writer->write_symbolID(fld.name()); // name
1158 writer->write_u1(sig2tag(sig)); // type
1159
1160 // value
1161 dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
1162 }
1163 }
1164
1165 // Add resolved_references for each class that has them
1166 oop resolved_references = ik->constants()->resolved_references_or_null();
1167 if (resolved_references != NULL) {
1168 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1169 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1170 writer->write_objectID(resolved_references);
1171
1172 // Also write any previous versions
1173 InstanceKlass* prev = ik->previous_versions();
1174 while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
1175 writer->write_symbolID(vmSymbols::resolved_references_name()); // name
1176 writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
1177 writer->write_objectID(prev->constants()->resolved_references());
1178 prev = prev->previous_versions();
1179 }
1180 }
1181
1182 // Add init lock to the end if the class is not yet initialized
1183 oop init_lock = ik->init_lock();
1184 if (init_lock != NULL) {
1185 writer->write_symbolID(vmSymbols::init_lock_name()); // name
1186 writer->write_u1(sig2tag(vmSymbols::int_array_signature())); // type
1187 writer->write_objectID(init_lock);
1188 }
1189 }
1190
1191 // dump the raw values of the instance fields of the given object
1192 void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o) {
1193 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1194
1195 for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
1196 if (!fld.access_flags().is_static()) {
1197 Symbol* sig = fld.signature();
1198 dump_field_value(writer, sig->char_at(0), o, fld.offset());
1199 }
1200 }
1201 }
1202
1203 // dumps the definition of the instance fields for a given class
1204 u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
1205 u2 field_count = 0;
1206
1207 for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
1208 if (!fldc.access_flags().is_static()) field_count++;
1209 }
1210
1211 return field_count;
1212 }
1213
1214 // dumps the definition of the instance fields for a given class
1215 void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
1216 InstanceKlass* ik = InstanceKlass::cast(k);
1217
1218 // dump the field descriptors
1219 for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
1220 if (!fld.access_flags().is_static()) {
1221 Symbol* sig = fld.signature();
1222
1223 writer->write_symbolID(fld.name()); // name
1224 writer->write_u1(sig2tag(sig)); // type
1225 }
1226 }
1227 }
1228
1229 // creates HPROF_GC_INSTANCE_DUMP record for the given object
1230 void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o) {
1231 InstanceKlass* ik = InstanceKlass::cast(o->klass());
1232 u4 is = instance_size(ik);
1233 u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
1234
1235 writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
1236 writer->write_objectID(o);
1237 writer->write_u4(STACK_TRACE_ID);
1238
1239 // class ID
1240 writer->write_classID(ik);
1241
1242 // number of bytes that follow
1243 writer->write_u4(is);
1244
1245 // field values
1246 dump_instance_fields(writer, o);
1247
1248 writer->end_sub_record();
1249 }
1250
1251 // creates HPROF_GC_CLASS_DUMP record for the given class and each of
1252 // its array classes
1253 void DumperSupport::dump_class_and_array_classes(AbstractDumpWriter* writer, Klass* k) {
1254 InstanceKlass* ik = InstanceKlass::cast(k);
1255
1256 // We can safepoint and do a heap dump at a point where we have a Klass,
1257 // but no java mirror class has been setup for it. So we need to check
1258 // that the class is at least loaded, to avoid crash from a null mirror.
1259 if (!ik->is_loaded()) {
1260 return;
1261 }
1262
1263 u2 static_fields_count = 0;
1264 u4 static_size = get_static_fields_size(ik, static_fields_count);
1265 u2 instance_fields_count = get_instance_fields_count(ik);
1266 u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
1267 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size;
1268
1269 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1270
1271 // class ID
1272 writer->write_classID(ik);
1273 writer->write_u4(STACK_TRACE_ID);
1274
1275 // super class ID
1276 InstanceKlass* java_super = ik->java_super();
1277 if (java_super == NULL) {
1278 writer->write_objectID(oop(NULL));
1279 } else {
1280 writer->write_classID(java_super);
1281 }
1282
1283 writer->write_objectID(ik->class_loader());
1284 writer->write_objectID(ik->signers());
1285 writer->write_objectID(ik->protection_domain());
1286
1287 // reserved
1288 writer->write_objectID(oop(NULL));
1289 writer->write_objectID(oop(NULL));
1290
1291 // instance size
1292 writer->write_u4(DumperSupport::instance_size(ik));
1293
1294 // size of constant pool - ignored by HAT 1.1
1295 writer->write_u2(0);
1296
1297 // static fields
1298 writer->write_u2(static_fields_count);
1299 dump_static_fields(writer, ik);
1300
1301 // description of instance fields
1302 writer->write_u2(instance_fields_count);
1303 dump_instance_field_descriptors(writer, ik);
1304
1305 writer->end_sub_record();
1306
1307 // array classes
1308 k = ik->array_klass_or_null();
1309 while (k != NULL) {
1310 assert(k->is_objArray_klass(), "not an ObjArrayKlass");
1311
1312 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1313 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1314 writer->write_classID(k);
1315 writer->write_u4(STACK_TRACE_ID);
1316
1317 // super class of array classes is java.lang.Object
1318 java_super = k->java_super();
1319 assert(java_super != NULL, "checking");
1320 writer->write_classID(java_super);
1321
1322 writer->write_objectID(ik->class_loader());
1323 writer->write_objectID(ik->signers());
1324 writer->write_objectID(ik->protection_domain());
1325
1326 writer->write_objectID(oop(NULL)); // reserved
1327 writer->write_objectID(oop(NULL));
1328 writer->write_u4(0); // instance size
1329 writer->write_u2(0); // constant pool
1330 writer->write_u2(0); // static fields
1331 writer->write_u2(0); // instance fields
1332
1333 writer->end_sub_record();
1334
1335 // get the array class for the next rank
1336 k = k->array_klass_or_null();
1337 }
1338 }
1339
1340 // creates HPROF_GC_CLASS_DUMP record for a given primitive array
1341 // class (and each multi-dimensional array class too)
1342 void DumperSupport::dump_basic_type_array_class(AbstractDumpWriter* writer, Klass* k) {
1343 // array classes
1344 while (k != NULL) {
1345 Klass* klass = k;
1346
1347 u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
1348 writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
1349 writer->write_classID(klass);
1350 writer->write_u4(STACK_TRACE_ID);
1351
1352 // super class of array classes is java.lang.Object
1353 InstanceKlass* java_super = klass->java_super();
1354 assert(java_super != NULL, "checking");
1355 writer->write_classID(java_super);
1356
1357 writer->write_objectID(oop(NULL)); // loader
1358 writer->write_objectID(oop(NULL)); // signers
1359 writer->write_objectID(oop(NULL)); // protection domain
1360
1361 writer->write_objectID(oop(NULL)); // reserved
1362 writer->write_objectID(oop(NULL));
1363 writer->write_u4(0); // instance size
1364 writer->write_u2(0); // constant pool
1365 writer->write_u2(0); // static fields
1366 writer->write_u2(0); // instance fields
1367
1368 writer->end_sub_record();
1369
1370 // get the array class for the next rank
1371 k = klass->array_klass_or_null();
1372 }
1373 }
1374
1375 // Hprof uses an u4 as record length field,
1376 // which means we need to truncate arrays that are too long.
1377 int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
1378 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1379 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1380
1381 int length = array->length();
1382
1383 int type_size;
1384 if (type == T_OBJECT) {
1385 type_size = sizeof(address);
1386 } else {
1387 type_size = type2aelembytes(type);
1388 }
1389
1390 size_t length_in_bytes = (size_t)length * type_size;
1391 uint max_bytes = max_juint - header_size;
1392
1393 if (length_in_bytes > max_bytes) {
1394 length = max_bytes / type_size;
1395 length_in_bytes = (size_t)length * type_size;
1396
1397 warning("cannot dump array of type %s[] with length %d; truncating to length %d",
1398 type2name_tab[type], array->length(), length);
1399 }
1400 return length;
1401 }
1402
1403 // creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
1404 void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
1405 // sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
1406 short header_size = 1 + 2 * 4 + 2 * sizeof(address);
1407 int length = calculate_array_max_length(writer, array, header_size);
1408 u4 size = header_size + length * sizeof(address);
1409
1410 writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
1411 writer->write_objectID(array);
1412 writer->write_u4(STACK_TRACE_ID);
1413 writer->write_u4(length);
1414
1415 // array class ID
1416 writer->write_classID(array->klass());
1417
1418 // [id]* elements
1419 for (int index = 0; index < length; index++) {
1420 oop o = array->obj_at(index);
1421 if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
1422 ResourceMark rm;
1423 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
1424 p2i(o), o->klass()->external_name(),
1425 p2i(array), array->klass()->external_name());
1426 }
1427 o = mask_dormant_archived_object(o);
1428 writer->write_objectID(o);
1429 }
1430
1431 writer->end_sub_record();
1432 }
1433
1434 #define WRITE_ARRAY(Array, Type, Size, Length) \
1435 for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
1436
1437 // creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
1438 void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
1439 BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
1440 // 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
1441 short header_size = 2 * 1 + 2 * 4 + sizeof(address);
1442
1443 int length = calculate_array_max_length(writer, array, header_size);
1444 int type_size = type2aelembytes(type);
1445 u4 length_in_bytes = (u4)length * type_size;
1446 u4 size = header_size + length_in_bytes;
1447
1448 writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
1449 writer->write_objectID(array);
1450 writer->write_u4(STACK_TRACE_ID);
1451 writer->write_u4(length);
1452 writer->write_u1(type2tag(type));
1453
1454 // nothing to copy
1455 if (length == 0) {
1456 writer->end_sub_record();
1457 return;
1458 }
1459
1460 // If the byte ordering is big endian then we can copy most types directly
1461
1462 switch (type) {
1463 case T_INT : {
1464 if (Endian::is_Java_byte_ordering_different()) {
1465 WRITE_ARRAY(array, int, u4, length);
1466 } else {
1467 writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes);
1468 }
1469 break;
1470 }
1471 case T_BYTE : {
1472 writer->write_raw((void*)(array->byte_at_addr(0)), length_in_bytes);
1473 break;
1474 }
1475 case T_CHAR : {
1476 if (Endian::is_Java_byte_ordering_different()) {
1477 WRITE_ARRAY(array, char, u2, length);
1478 } else {
1479 writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes);
1480 }
1481 break;
1482 }
1483 case T_SHORT : {
1484 if (Endian::is_Java_byte_ordering_different()) {
1485 WRITE_ARRAY(array, short, u2, length);
1486 } else {
1487 writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes);
1488 }
1489 break;
1490 }
1491 case T_BOOLEAN : {
1492 if (Endian::is_Java_byte_ordering_different()) {
1493 WRITE_ARRAY(array, bool, u1, length);
1494 } else {
1495 writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes);
1496 }
1497 break;
1498 }
1499 case T_LONG : {
1500 if (Endian::is_Java_byte_ordering_different()) {
1501 WRITE_ARRAY(array, long, u8, length);
1502 } else {
1503 writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes);
1504 }
1505 break;
1506 }
1507
1508 // handle float/doubles in a special value to ensure than NaNs are
1509 // written correctly. TO DO: Check if we can avoid this on processors that
1510 // use IEEE 754.
1511
1512 case T_FLOAT : {
1513 for (int i = 0; i < length; i++) {
1514 dump_float(writer, array->float_at(i));
1515 }
1516 break;
1517 }
1518 case T_DOUBLE : {
1519 for (int i = 0; i < length; i++) {
1520 dump_double(writer, array->double_at(i));
1521 }
1522 break;
1523 }
1524 default : ShouldNotReachHere();
1525 }
1526
1527 writer->end_sub_record();
1528 }
1529
1530 // create a HPROF_FRAME record of the given Method* and bci
1531 void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
1532 int frame_serial_num,
1533 int class_serial_num,
1534 Method* m,
1535 int bci) {
1536 int line_number;
1537 if (m->is_native()) {
1538 line_number = -3; // native frame
1539 } else {
1540 line_number = m->line_number_from_bci(bci);
1541 }
1542
1543 write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
1544 writer->write_id(frame_serial_num); // frame serial number
1545 writer->write_symbolID(m->name()); // method's name
1546 writer->write_symbolID(m->signature()); // method's signature
1547
1548 assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
1549 writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
1550 writer->write_u4(class_serial_num); // class serial number
1551 writer->write_u4((u4) line_number); // line number
1552 }
1553
1554
1555 // Support class used to generate HPROF_UTF8 records from the entries in the
1556 // SymbolTable.
1557
1558 class SymbolTableDumper : public SymbolClosure {
1559 private:
1560 AbstractDumpWriter* _writer;
1561 AbstractDumpWriter* writer() const { return _writer; }
1562 public:
1563 SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
1564 void do_symbol(Symbol** p);
1565 };
1566
1567 void SymbolTableDumper::do_symbol(Symbol** p) {
1568 ResourceMark rm;
1569 Symbol* sym = *p;
1570 int len = sym->utf8_length();
1571 if (len > 0) {
1572 char* s = sym->as_utf8();
1573 DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
1574 writer()->write_symbolID(sym);
1575 writer()->write_raw(s, len);
1576 }
1577 }
1578
1579 // Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
1580
1581 class JNILocalsDumper : public OopClosure {
1582 private:
1583 AbstractDumpWriter* _writer;
1584 u4 _thread_serial_num;
1585 int _frame_num;
1586 AbstractDumpWriter* writer() const { return _writer; }
1587 public:
1588 JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
1589 _writer = writer;
1590 _thread_serial_num = thread_serial_num;
1591 _frame_num = -1; // default - empty stack
1592 }
1593 void set_frame_number(int n) { _frame_num = n; }
1594 void do_oop(oop* obj_p);
1595 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1596 };
1597
1598
1599 void JNILocalsDumper::do_oop(oop* obj_p) {
1600 // ignore null handles
1601 oop o = *obj_p;
1602 if (o != NULL) {
1603 u4 size = 1 + sizeof(address) + 4 + 4;
1604 writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
1605 writer()->write_objectID(o);
1606 writer()->write_u4(_thread_serial_num);
1607 writer()->write_u4((u4)_frame_num);
1608 writer()->end_sub_record();
1609 }
1610 }
1611
1612
1613 // Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
1614
1615 class JNIGlobalsDumper : public OopClosure {
1616 private:
1617 AbstractDumpWriter* _writer;
1618 AbstractDumpWriter* writer() const { return _writer; }
1619
1620 public:
1621 JNIGlobalsDumper(AbstractDumpWriter* writer) {
1622 _writer = writer;
1623 }
1624 void do_oop(oop* obj_p);
1625 void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
1626 };
1627
1628 void JNIGlobalsDumper::do_oop(oop* obj_p) {
1629 oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
1630
1631 // ignore these
1632 if (o == NULL) return;
1633 // we ignore global ref to symbols and other internal objects
1634 if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
1635 u4 size = 1 + 2 * sizeof(address);
1636 writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
1637 writer()->write_objectID(o);
1638 writer()->write_objectID((oopDesc*)obj_p); // global ref ID
1639 writer()->end_sub_record();
1640 }
1641 };
1642
1643 // Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
1644
1645 class StickyClassDumper : public KlassClosure {
1646 private:
1647 AbstractDumpWriter* _writer;
1648 AbstractDumpWriter* writer() const { return _writer; }
1649 public:
1650 StickyClassDumper(AbstractDumpWriter* writer) {
1651 _writer = writer;
1652 }
1653 void do_klass(Klass* k) {
1654 if (k->is_instance_klass()) {
1655 InstanceKlass* ik = InstanceKlass::cast(k);
1656 u4 size = 1 + sizeof(address);
1657 writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
1658 writer()->write_classID(ik);
1659 writer()->end_sub_record();
1660 }
1661 }
1662 };
1663
1664 // Large object heap dump support.
1665 // To avoid memory consumption, when dumping large objects such as huge array and
1666 // large objects whose size are larger than LARGE_OBJECT_DUMP_THRESHOLD, the scanned
1667 // partial object/array data will be sent to the backend directly instead of caching
1668 // the whole object/array in the internal buffer.
1669 // The HeapDumpLargeObjectList is used to save the large object when dumper scans
1670 // the heap. The large objects could be added (push) parallelly by multiple dumpers,
1671 // But they will be removed (popped) serially only by the VM thread.
1672 class HeapDumpLargeObjectList : public CHeapObj<mtInternal> {
1673 private:
1674 class HeapDumpLargeObjectListElem : public CHeapObj<mtInternal> {
1675 public:
1676 HeapDumpLargeObjectListElem(oop obj) : _obj(obj), _next(NULL) { }
1677 oop _obj;
1678 HeapDumpLargeObjectListElem* _next;
1679 };
1680
1681 volatile HeapDumpLargeObjectListElem* _head;
1682
1683 public:
1684 HeapDumpLargeObjectList() : _head(NULL) { }
1685
1686 void atomic_push(oop obj) {
1687 assert (obj != NULL, "sanity check");
1688 HeapDumpLargeObjectListElem* entry = new HeapDumpLargeObjectListElem(obj);
1689 if (entry == NULL) {
1690 warning("failed to allocate element for large object list");
1691 return;
1692 }
1693 assert (entry->_obj != NULL, "sanity check");
1694 while (true) {
1695 volatile HeapDumpLargeObjectListElem* old_head = Atomic::load_acquire(&_head);
1696 HeapDumpLargeObjectListElem* new_head = entry;
1697 if (Atomic::cmpxchg(&_head, old_head, new_head) == old_head) {
1698 // successfully push
1699 new_head->_next = (HeapDumpLargeObjectListElem*)old_head;
1700 return;
1701 }
1702 }
1703 }
1704
1705 oop pop() {
1706 if (_head == NULL) {
1707 return NULL;
1708 }
1709 HeapDumpLargeObjectListElem* entry = (HeapDumpLargeObjectListElem*)_head;
1710 _head = _head->_next;
1711 assert (entry != NULL, "illegal larger object list entry");
1712 oop ret = entry->_obj;
1713 delete entry;
1714 assert (ret != NULL, "illegal oop pointer");
1715 return ret;
1716 }
1717
1718 void drain(ObjectClosure* cl) {
1719 while (_head != NULL) {
1720 cl->do_object(pop());
1721 }
1722 }
1723
1724 bool is_empty() {
1725 return _head == NULL;
1726 }
1727
1728 static const size_t LargeObjectSizeThreshold = 1 << 20; // 1 MB
1729 };
1730
1731 class VM_HeapDumper;
1732
1733 // Support class using when iterating over the heap.
1734 class HeapObjectDumper : public ObjectClosure {
1735 private:
1736 AbstractDumpWriter* _writer;
1737 HeapDumpLargeObjectList* _list;
1738
1739 AbstractDumpWriter* writer() { return _writer; }
1740 bool is_large(oop o);
1741 public:
1742 HeapObjectDumper(AbstractDumpWriter* writer, HeapDumpLargeObjectList* list = NULL) {
1743 _writer = writer;
1744 _list = list;
1745 }
1746
1747 // called for each object in the heap
1748 void do_object(oop o);
1749 };
1750
1751 void HeapObjectDumper::do_object(oop o) {
1752 // skip classes as these emitted as HPROF_GC_CLASS_DUMP records
1753 if (o->klass() == vmClasses::Class_klass()) {
1754 if (!java_lang_Class::is_primitive(o)) {
1755 return;
1756 }
1757 }
1758
1759 if (DumperSupport::mask_dormant_archived_object(o) == NULL) {
1760 log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o), o->klass()->external_name());
1761 return;
1762 }
1763
1764 // If large object list exists and it is large object/array,
1765 // add oop into the list and skip scan. VM thread will process it later.
1766 if (_list != NULL && is_large(o)) {
1767 _list->atomic_push(o);
1768 return;
1769 }
1770
1771 if (o->is_instance()) {
1772 // create a HPROF_GC_INSTANCE record for each object
1773 DumperSupport::dump_instance(writer(), o);
1774 } else if (o->is_objArray()) {
1775 // create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
1776 DumperSupport::dump_object_array(writer(), objArrayOop(o));
1777 } else if (o->is_typeArray()) {
1778 // create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
1779 DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
1780 }
1781 }
1782
1783 bool HeapObjectDumper::is_large(oop o) {
1784 size_t size = 0;
1785 if (o->is_instance()) {
1786 // Use o->size() * 8 as the upper limit of instance size to avoid iterating static fields
1787 size = o->size() * 8;
1788 } else if (o->is_objArray()) {
1789 objArrayOop array = objArrayOop(o);
1790 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1791 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1792 int length = array->length();
1793 int type_size = sizeof(address);
1794 size = (size_t)length * type_size;
1795 } else if (o->is_typeArray()) {
1796 typeArrayOop array = typeArrayOop(o);
1797 BasicType type = ArrayKlass::cast(array->klass())->element_type();
1798 assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
1799 int length = array->length();
1800 int type_size = type2aelembytes(type);
1801 size = (size_t)length * type_size;
1802 }
1803 return size > HeapDumpLargeObjectList::LargeObjectSizeThreshold;
1804 }
1805
1806 // The dumper controller for parallel heap dump
1807 class DumperController : public CHeapObj<mtInternal> {
1808 private:
1809 bool _started;
1810 Monitor* _lock;
1811 uint _dumper_number;
1812 uint _complete_number;
1813
1814 public:
1815 DumperController(uint number) :
1816 _started(false),
1817 _lock(new (std::nothrow) PaddedMonitor(Mutex::nonleaf, "DumperController_lock",
1818 Mutex::_safepoint_check_always)),
1819 _dumper_number(number),
1820 _complete_number(0) { }
1821
1822 ~DumperController() { delete _lock; }
1823
1824 void wait_for_start_signal() {
1825 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1826 while (_started == false) {
1827 ml.wait();
1828 }
1829 assert(_started == true, "dumper woke up with wrong state");
1830 }
1831
1832 void start_dump() {
1833 assert (_started == false, "start dump with wrong state");
1834 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1835 _started = true;
1836 ml.notify_all();
1837 }
1838
1839 void dumper_complete() {
1840 assert (_started == true, "dumper complete with wrong state");
1841 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1842 _complete_number++;
1843 ml.notify();
1844 }
1845
1846 void wait_all_dumpers_complete() {
1847 assert (_started == true, "wrong state when wait for dumper complete");
1848 MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
1849 while (_complete_number != _dumper_number) {
1850 ml.wait();
1851 }
1852 _started = false;
1853 }
1854 };
1855
1856 // The VM operation that performs the heap dump
1857 class VM_HeapDumper : public VM_GC_Operation, public AbstractGangTask {
1858 private:
1859 static VM_HeapDumper* _global_dumper;
1860 static DumpWriter* _global_writer;
1861 DumpWriter* _local_writer;
1862 JavaThread* _oome_thread;
1863 Method* _oome_constructor;
1864 bool _gc_before_heap_dump;
1865 GrowableArray<Klass*>* _klass_map;
1866 ThreadStackTrace** _stack_traces;
1867 int _num_threads;
1868 // parallel heap dump support
1869 uint _num_dumper_threads;
1870 uint _num_writer_threads;
1871 DumperController* _dumper_controller;
1872 ParallelObjectIterator* _poi;
1873 HeapDumpLargeObjectList* _large_object_list;
1874
1875 // VMDumperType is for thread that dumps both heap and non-heap data.
1876 static const size_t VMDumperType = 0;
1877 static const size_t WriterType = 1;
1878 static const size_t DumperType = 2;
1879 // worker id of VMDumper thread.
1880 static const size_t VMDumperWorkerId = 0;
1881
1882 size_t get_worker_type(uint worker_id) {
1883 assert(_num_writer_threads >= 1, "Must be at least one writer");
1884 // worker id of VMDumper that dump heap and non-heap data
1885 if (worker_id == VMDumperWorkerId) {
1886 return VMDumperType;
1887 }
1888
1889 // worker id of dumper starts from 1, which only dump heap datar
1890 if (worker_id < _num_dumper_threads) {
1891 return DumperType;
1892 }
1893
1894 // worker id of writer starts from _num_dumper_threads
1895 return WriterType;
1896 }
1897
1898 void prepare_parallel_dump(uint num_total) {
1899 assert (_dumper_controller == NULL, "dumper controller must be NULL");
1900 assert (num_total > 0, "active workers number must >= 1");
1901 // Dumper threads number must not be larger than active workers number.
1902 if (num_total < _num_dumper_threads) {
1903 _num_dumper_threads = num_total - 1;
1904 }
1905 // Calculate dumper and writer threads number.
1906 _num_writer_threads = num_total - _num_dumper_threads;
1907 // If dumper threads number is 1, only the VMThread works as a dumper.
1908 // If dumper threads number is equal to active workers, need at lest one worker thread as writer.
1909 if (_num_dumper_threads > 0 && _num_writer_threads == 0) {
1910 _num_writer_threads = 1;
1911 _num_dumper_threads = num_total - _num_writer_threads;
1912 }
1913 // Prepare parallel writer.
1914 if (_num_dumper_threads > 1) {
1915 ParDumpWriter::before_work();
1916 // Number of dumper threads that only iterate heap.
1917 uint _heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */;
1918 _dumper_controller = new (std::nothrow) DumperController(_heap_only_dumper_threads);
1919 _poi = Universe::heap()->parallel_object_iterator(_num_dumper_threads);
1920 }
1921 }
1922
1923 void finish_parallel_dump() {
1924 if (_num_dumper_threads > 1) {
1925 ParDumpWriter::after_work();
1926 }
1927 }
1928
1929 // accessors and setters
1930 static VM_HeapDumper* dumper() { assert(_global_dumper != NULL, "Error"); return _global_dumper; }
1931 static DumpWriter* writer() { assert(_global_writer != NULL, "Error"); return _global_writer; }
1932 void set_global_dumper() {
1933 assert(_global_dumper == NULL, "Error");
1934 _global_dumper = this;
1935 }
1936 void set_global_writer() {
1937 assert(_global_writer == NULL, "Error");
1938 _global_writer = _local_writer;
1939 }
1940 void clear_global_dumper() { _global_dumper = NULL; }
1941 void clear_global_writer() { _global_writer = NULL; }
1942
1943 bool skip_operation() const;
1944
1945 // writes a HPROF_LOAD_CLASS record
1946 class ClassesDo;
1947 static void do_load_class(Klass* k);
1948
1949 // writes a HPROF_GC_CLASS_DUMP record for the given class
1950 // (and each array class too)
1951 static void do_class_dump(Klass* k);
1952
1953 // writes a HPROF_GC_CLASS_DUMP records for a given basic type
1954 // array (and each multi-dimensional array too)
1955 static void do_basic_type_array_class_dump(Klass* k);
1956
1957 // HPROF_GC_ROOT_THREAD_OBJ records
1958 int do_thread(JavaThread* thread, u4 thread_serial_num);
1959 void do_threads();
1960
1961 void add_class_serial_number(Klass* k, int serial_num) {
1962 _klass_map->at_put_grow(serial_num, k);
1963 }
1964
1965 // HPROF_TRACE and HPROF_FRAME records
1966 void dump_stack_traces();
1967
1968 // large objects
1969 void dump_large_objects(ObjectClosure* writer);
1970
1971 public:
1972 VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome, uint num_dump_threads) :
1973 VM_GC_Operation(0 /* total collections, dummy, ignored */,
1974 GCCause::_heap_dump /* GC Cause */,
1975 0 /* total full collections, dummy, ignored */,
1976 gc_before_heap_dump),
1977 AbstractGangTask("dump heap") {
1978 _local_writer = writer;
1979 _gc_before_heap_dump = gc_before_heap_dump;
1980 _klass_map = new (ResourceObj::C_HEAP, mtServiceability) GrowableArray<Klass*>(INITIAL_CLASS_COUNT, mtServiceability);
1981 _stack_traces = NULL;
1982 _num_threads = 0;
1983 _num_dumper_threads = num_dump_threads;
1984 _dumper_controller = NULL;
1985 _poi = NULL;
1986 _large_object_list = new (std::nothrow) HeapDumpLargeObjectList();
1987 if (oome) {
1988 assert(!Thread::current()->is_VM_thread(), "Dump from OutOfMemoryError cannot be called by the VMThread");
1989 // get OutOfMemoryError zero-parameter constructor
1990 InstanceKlass* oome_ik = vmClasses::OutOfMemoryError_klass();
1991 _oome_constructor = oome_ik->find_method(vmSymbols::object_initializer_name(),
1992 vmSymbols::void_method_signature());
1993 // get thread throwing OOME when generating the heap dump at OOME
1994 _oome_thread = JavaThread::current();
1995 } else {
1996 _oome_thread = NULL;
1997 _oome_constructor = NULL;
1998 }
1999 }
2000
2001 ~VM_HeapDumper() {
2002 if (_stack_traces != NULL) {
2003 for (int i=0; i < _num_threads; i++) {
2004 delete _stack_traces[i];
2005 }
2006 FREE_C_HEAP_ARRAY(ThreadStackTrace*, _stack_traces);
2007 }
2008 if (_poi != NULL) {
2009 delete _poi;
2010 _poi = NULL;
2011 }
2012 if (_dumper_controller != NULL) {
2013 delete _dumper_controller;
2014 _dumper_controller = NULL;
2015 }
2016 delete _klass_map;
2017 delete _large_object_list;
2018 }
2019
2020 VMOp_Type type() const { return VMOp_HeapDumper; }
2021 void doit();
2022 void work(uint worker_id);
2023 };
2024
2025 VM_HeapDumper* VM_HeapDumper::_global_dumper = NULL;
2026 DumpWriter* VM_HeapDumper::_global_writer = NULL;
2027
2028 bool VM_HeapDumper::skip_operation() const {
2029 return false;
2030 }
2031
2032 // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
2033 void DumperSupport::end_of_dump(AbstractDumpWriter* writer) {
2034 writer->finish_dump_segment();
2035
2036 writer->write_u1(HPROF_HEAP_DUMP_END);
2037 writer->write_u4(0);
2038 writer->write_u4(0);
2039 }
2040
2041 // writes a HPROF_LOAD_CLASS record for the class (and each of its
2042 // array classes)
2043 void VM_HeapDumper::do_load_class(Klass* k) {
2044 static u4 class_serial_num = 0;
2045
2046 // len of HPROF_LOAD_CLASS record
2047 u4 remaining = 2*oopSize + 2*sizeof(u4);
2048
2049 // write a HPROF_LOAD_CLASS for the class and each array class
2050 do {
2051 DumperSupport::write_header(writer(), HPROF_LOAD_CLASS, remaining);
2052
2053 // class serial number is just a number
2054 writer()->write_u4(++class_serial_num);
2055
2056 // class ID
2057 Klass* klass = k;
2058 writer()->write_classID(klass);
2059
2060 // add the Klass* and class serial number pair
2061 dumper()->add_class_serial_number(klass, class_serial_num);
2062
2063 writer()->write_u4(STACK_TRACE_ID);
2064
2065 // class name ID
2066 Symbol* name = klass->name();
2067 writer()->write_symbolID(name);
2068
2069 // write a LOAD_CLASS record for the array type (if it exists)
2070 k = klass->array_klass_or_null();
2071 } while (k != NULL);
2072 }
2073
2074 // writes a HPROF_GC_CLASS_DUMP record for the given class
2075 void VM_HeapDumper::do_class_dump(Klass* k) {
2076 if (k->is_instance_klass()) {
2077 DumperSupport::dump_class_and_array_classes(writer(), k);
2078 }
2079 }
2080
2081 // writes a HPROF_GC_CLASS_DUMP records for a given basic type
2082 // array (and each multi-dimensional array too)
2083 void VM_HeapDumper::do_basic_type_array_class_dump(Klass* k) {
2084 DumperSupport::dump_basic_type_array_class(writer(), k);
2085 }
2086
2087 // Walk the stack of the given thread.
2088 // Dumps a HPROF_GC_ROOT_JAVA_FRAME record for each local
2089 // Dumps a HPROF_GC_ROOT_JNI_LOCAL record for each JNI local
2090 //
2091 // It returns the number of Java frames in this thread stack
2092 int VM_HeapDumper::do_thread(JavaThread* java_thread, u4 thread_serial_num) {
2093 JNILocalsDumper blk(writer(), thread_serial_num);
2094
2095 oop threadObj = java_thread->threadObj();
2096 assert(threadObj != NULL, "sanity check");
2097
2098 int stack_depth = 0;
2099 if (java_thread->has_last_Java_frame()) {
2100
2101 // vframes are resource allocated
2102 Thread* current_thread = Thread::current();
2103 ResourceMark rm(current_thread);
2104 HandleMark hm(current_thread);
2105
2106 RegisterMap reg_map(java_thread);
2107 frame f = java_thread->last_frame();
2108 vframe* vf = vframe::new_vframe(&f, ®_map, java_thread);
2109 frame* last_entry_frame = NULL;
2110 int extra_frames = 0;
2111
2112 if (java_thread == _oome_thread && _oome_constructor != NULL) {
2113 extra_frames++;
2114 }
2115 while (vf != NULL) {
2116 blk.set_frame_number(stack_depth);
2117 if (vf->is_java_frame()) {
2118
2119 // java frame (interpreted, compiled, ...)
2120 javaVFrame *jvf = javaVFrame::cast(vf);
2121 if (!(jvf->method()->is_native())) {
2122 StackValueCollection* locals = jvf->locals();
2123 for (int slot=0; slot<locals->size(); slot++) {
2124 if (locals->at(slot)->type() == T_OBJECT) {
2125 oop o = locals->obj_at(slot)();
2126
2127 if (o != NULL) {
2128 u4 size = 1 + sizeof(address) + 4 + 4;
2129 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2130 writer()->write_objectID(o);
2131 writer()->write_u4(thread_serial_num);
2132 writer()->write_u4((u4) (stack_depth + extra_frames));
2133 writer()->end_sub_record();
2134 }
2135 }
2136 }
2137 StackValueCollection *exprs = jvf->expressions();
2138 for(int index = 0; index < exprs->size(); index++) {
2139 if (exprs->at(index)->type() == T_OBJECT) {
2140 oop o = exprs->obj_at(index)();
2141 if (o != NULL) {
2142 u4 size = 1 + sizeof(address) + 4 + 4;
2143 writer()->start_sub_record(HPROF_GC_ROOT_JAVA_FRAME, size);
2144 writer()->write_objectID(o);
2145 writer()->write_u4(thread_serial_num);
2146 writer()->write_u4((u4) (stack_depth + extra_frames));
2147 writer()->end_sub_record();
2148 }
2149 }
2150 }
2151 } else {
2152 // native frame
2153 if (stack_depth == 0) {
2154 // JNI locals for the top frame.
2155 java_thread->active_handles()->oops_do(&blk);
2156 } else {
2157 if (last_entry_frame != NULL) {
2158 // JNI locals for the entry frame
2159 assert(last_entry_frame->is_entry_frame(), "checking");
2160 last_entry_frame->entry_frame_call_wrapper()->handles()->oops_do(&blk);
2161 }
2162 }
2163 }
2164 // increment only for Java frames
2165 stack_depth++;
2166 last_entry_frame = NULL;
2167
2168 } else {
2169 // externalVFrame - if it's an entry frame then report any JNI locals
2170 // as roots when we find the corresponding native javaVFrame
2171 frame* fr = vf->frame_pointer();
2172 assert(fr != NULL, "sanity check");
2173 if (fr->is_entry_frame()) {
2174 last_entry_frame = fr;
2175 }
2176 }
2177 vf = vf->sender();
2178 }
2179 } else {
2180 // no last java frame but there may be JNI locals
2181 java_thread->active_handles()->oops_do(&blk);
2182 }
2183 return stack_depth;
2184 }
2185
2186
2187 // write a HPROF_GC_ROOT_THREAD_OBJ record for each java thread. Then walk
2188 // the stack so that locals and JNI locals are dumped.
2189 void VM_HeapDumper::do_threads() {
2190 for (int i=0; i < _num_threads; i++) {
2191 JavaThread* thread = _stack_traces[i]->thread();
2192 oop threadObj = thread->threadObj();
2193 u4 thread_serial_num = i+1;
2194 u4 stack_serial_num = thread_serial_num + STACK_TRACE_ID;
2195 u4 size = 1 + sizeof(address) + 4 + 4;
2196 writer()->start_sub_record(HPROF_GC_ROOT_THREAD_OBJ, size);
2197 writer()->write_objectID(threadObj);
2198 writer()->write_u4(thread_serial_num); // thread number
2199 writer()->write_u4(stack_serial_num); // stack trace serial number
2200 writer()->end_sub_record();
2201 int num_frames = do_thread(thread, thread_serial_num);
2202 assert(num_frames == _stack_traces[i]->get_stack_depth(),
2203 "total number of Java frames not matched");
2204 }
2205 }
2206
2207
2208 // The VM operation that dumps the heap. The dump consists of the following
2209 // records:
2210 //
2211 // HPROF_HEADER
2212 // [HPROF_UTF8]*
2213 // [HPROF_LOAD_CLASS]*
2214 // [[HPROF_FRAME]*|HPROF_TRACE]*
2215 // [HPROF_GC_CLASS_DUMP]*
2216 // [HPROF_HEAP_DUMP_SEGMENT]*
2217 // HPROF_HEAP_DUMP_END
2218 //
2219 // The HPROF_TRACE records represent the stack traces where the heap dump
2220 // is generated and a "dummy trace" record which does not include
2221 // any frames. The dummy trace record is used to be referenced as the
2222 // unknown object alloc site.
2223 //
2224 // Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records.
2225 // To allow the heap dump be generated in a single pass we remember the position
2226 // of the dump length and fix it up after all sub-records have been written.
2227 // To generate the sub-records we iterate over the heap, writing
2228 // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP
2229 // records as we go. Once that is done we write records for some of the GC
2230 // roots.
2231
2232 void VM_HeapDumper::doit() {
2233
2234 CollectedHeap* ch = Universe::heap();
2235
2236 ch->ensure_parsability(false); // must happen, even if collection does
2237 // not happen (e.g. due to GCLocker)
2238
2239 if (_gc_before_heap_dump) {
2240 if (GCLocker::is_active()) {
2241 warning("GC locker is held; pre-heapdump GC was skipped");
2242 } else {
2243 ch->collect_as_vm_thread(GCCause::_heap_dump);
2244 }
2245 }
2246
2247 // At this point we should be the only dumper active, so
2248 // the following should be safe.
2249 set_global_dumper();
2250 set_global_writer();
2251
2252 WorkGang* gang = ch->safepoint_workers();
2253
2254 if (gang == NULL) {
2255 // Use serial dump, set dumper threads and writer threads number to 1.
2256 _num_dumper_threads=1;
2257 _num_writer_threads=1;
2258 work(0);
2259 } else {
2260 prepare_parallel_dump(gang->active_workers());
2261 gang->run_task(this);
2262 finish_parallel_dump();
2263 }
2264
2265 // Now we clear the global variables, so that a future dumper can run.
2266 clear_global_dumper();
2267 clear_global_writer();
2268 }
2269
2270 void VM_HeapDumper::work(uint worker_id) {
2271 if (worker_id != 0) {
2272 if (get_worker_type(worker_id) == WriterType) {
2273 writer()->writer_loop();
2274 return;
2275 }
2276 if (_num_dumper_threads > 1 && get_worker_type(worker_id) == DumperType) {
2277 _dumper_controller->wait_for_start_signal();
2278 }
2279 } else {
2280 // The worker 0 on all non-heap data dumping and part of heap iteration.
2281 // Write the file header - we always use 1.0.2
2282 const char* header = "JAVA PROFILE 1.0.2";
2283
2284 // header is few bytes long - no chance to overflow int
2285 writer()->write_raw((void*)header, (int)strlen(header));
2286 writer()->write_u1(0); // terminator
2287 writer()->write_u4(oopSize);
2288 // timestamp is current time in ms
2289 writer()->write_u8(os::javaTimeMillis());
2290 // HPROF_UTF8 records
2291 SymbolTableDumper sym_dumper(writer());
2292 SymbolTable::symbols_do(&sym_dumper);
2293
2294 // write HPROF_LOAD_CLASS records
2295 {
2296 LockedClassesDo locked_load_classes(&do_load_class);
2297 ClassLoaderDataGraph::classes_do(&locked_load_classes);
2298 }
2299 Universe::basic_type_classes_do(&do_load_class);
2300
2301 // write HPROF_FRAME and HPROF_TRACE records
2302 // this must be called after _klass_map is built when iterating the classes above.
2303 dump_stack_traces();
2304
2305 // Writes HPROF_GC_CLASS_DUMP records
2306 {
2307 LockedClassesDo locked_dump_class(&do_class_dump);
2308 ClassLoaderDataGraph::classes_do(&locked_dump_class);
2309 }
2310 Universe::basic_type_classes_do(&do_basic_type_array_class_dump);
2311
2312 // HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
2313 do_threads();
2314
2315 // HPROF_GC_ROOT_JNI_GLOBAL
2316 JNIGlobalsDumper jni_dumper(writer());
2317 JNIHandles::oops_do(&jni_dumper);
2318 // technically not jni roots, but global roots
2319 // for things like preallocated throwable backtraces
2320 Universe::vm_global()->oops_do(&jni_dumper);
2321 // HPROF_GC_ROOT_STICKY_CLASS
2322 // These should be classes in the NULL class loader data, and not all classes
2323 // if !ClassUnloading
2324 StickyClassDumper class_dumper(writer());
2325 ClassLoaderData::the_null_class_loader_data()->classes_do(&class_dumper);
2326 }
2327 // writes HPROF_GC_INSTANCE_DUMP records.
2328 // After each sub-record is written check_segment_length will be invoked
2329 // to check if the current segment exceeds a threshold. If so, a new
2330 // segment is started.
2331 // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
2332 // of the heap dump.
2333 if (_num_dumper_threads <= 1) {
2334 HeapObjectDumper obj_dumper(writer());
2335 Universe::heap()->object_iterate(&obj_dumper);
2336 } else {
2337 assert(get_worker_type(worker_id) == DumperType
2338 || get_worker_type(worker_id) == VMDumperType,
2339 "must be dumper thread to do heap iteration");
2340 if (get_worker_type(worker_id) == VMDumperType) {
2341 // Clear global writer's buffer.
2342 writer()->finish_dump_segment(true);
2343 // Notify dumpers to start heap iteration.
2344 _dumper_controller->start_dump();
2345 }
2346 // Heap iteration.
2347 {
2348 ParDumpWriter pw(writer());
2349 {
2350 HeapObjectDumper obj_dumper(&pw, _large_object_list);
2351 _poi->object_iterate(&obj_dumper, worker_id);
2352 }
2353
2354 if (get_worker_type(worker_id) == VMDumperType) {
2355 _dumper_controller->wait_all_dumpers_complete();
2356 // clear internal buffer;
2357 pw.finish_dump_segment(true);
2358 // refresh the global_writer's buffer and position;
2359 writer()->refresh();
2360 } else {
2361 pw.finish_dump_segment(true);
2362 _dumper_controller->dumper_complete();
2363 return;
2364 }
2365 }
2366 }
2367
2368 assert(get_worker_type(worker_id) == VMDumperType, "Heap dumper must be VMDumper");
2369 // Use writer() rather than ParDumpWriter to avoid memory consumption.
2370 HeapObjectDumper obj_dumper(writer());
2371 dump_large_objects(&obj_dumper);
2372 // Writes the HPROF_HEAP_DUMP_END record.
2373 DumperSupport::end_of_dump(writer());
2374 // We are done with writing. Release the worker threads.
2375 writer()->deactivate();
2376 }
2377
2378 void VM_HeapDumper::dump_stack_traces() {
2379 // write a HPROF_TRACE record without any frames to be referenced as object alloc sites
2380 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4));
2381 writer()->write_u4((u4) STACK_TRACE_ID);
2382 writer()->write_u4(0); // thread number
2383 writer()->write_u4(0); // frame count
2384
2385 _stack_traces = NEW_C_HEAP_ARRAY(ThreadStackTrace*, Threads::number_of_threads(), mtInternal);
2386 int frame_serial_num = 0;
2387 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
2388 oop threadObj = thread->threadObj();
2389 if (threadObj != NULL && !thread->is_exiting() && !thread->is_hidden_from_external_view()) {
2390 // dump thread stack trace
2391 Thread* current_thread = Thread::current();
2392 ResourceMark rm(current_thread);
2393 HandleMark hm(current_thread);
2394
2395 ThreadStackTrace* stack_trace = new ThreadStackTrace(thread, false);
2396 stack_trace->dump_stack_at_safepoint(-1);
2397 _stack_traces[_num_threads++] = stack_trace;
2398
2399 // write HPROF_FRAME records for this thread's stack trace
2400 int depth = stack_trace->get_stack_depth();
2401 int thread_frame_start = frame_serial_num;
2402 int extra_frames = 0;
2403 // write fake frame that makes it look like the thread, which caused OOME,
2404 // is in the OutOfMemoryError zero-parameter constructor
2405 if (thread == _oome_thread && _oome_constructor != NULL) {
2406 int oome_serial_num = _klass_map->find(_oome_constructor->method_holder());
2407 // the class serial number starts from 1
2408 assert(oome_serial_num > 0, "OutOfMemoryError class not found");
2409 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, oome_serial_num,
2410 _oome_constructor, 0);
2411 extra_frames++;
2412 }
2413 for (int j=0; j < depth; j++) {
2414 StackFrameInfo* frame = stack_trace->stack_frame_at(j);
2415 Method* m = frame->method();
2416 int class_serial_num = _klass_map->find(m->method_holder());
2417 // the class serial number starts from 1
2418 assert(class_serial_num > 0, "class not found");
2419 DumperSupport::dump_stack_frame(writer(), ++frame_serial_num, class_serial_num, m, frame->bci());
2420 }
2421 depth += extra_frames;
2422
2423 // write HPROF_TRACE record for one thread
2424 DumperSupport::write_header(writer(), HPROF_TRACE, 3*sizeof(u4) + depth*oopSize);
2425 int stack_serial_num = _num_threads + STACK_TRACE_ID;
2426 writer()->write_u4(stack_serial_num); // stack trace serial number
2427 writer()->write_u4((u4) _num_threads); // thread serial number
2428 writer()->write_u4(depth); // frame count
2429 for (int j=1; j <= depth; j++) {
2430 writer()->write_id(thread_frame_start + j);
2431 }
2432 }
2433 }
2434 }
2435
2436 // dump the large objects.
2437 void VM_HeapDumper::dump_large_objects(ObjectClosure* cl) {
2438 _large_object_list->drain(cl);
2439 }
2440
2441 // dump the heap to given path.
2442 int HeapDumper::dump(const char* path, outputStream* out, int compression, bool overwrite, uint num_dump_threads) {
2443 assert(path != NULL && strlen(path) > 0, "path missing");
2444
2445 // print message in interactive case
2446 if (out != NULL) {
2447 out->print_cr("Dumping heap to %s ...", path);
2448 timer()->start();
2449 }
2450 // create JFR event
2451 EventHeapDump event;
2452
2453 AbstractCompressor* compressor = NULL;
2454
2455 if (compression > 0) {
2456 compressor = new (std::nothrow) GZipCompressor(compression);
2457
2458 if (compressor == NULL) {
2459 set_error("Could not allocate gzip compressor");
2460 return -1;
2461 }
2462 }
2463
2464 DumpWriter writer(new (std::nothrow) FileWriter(path, overwrite), compressor);
2465
2466 if (writer.error() != NULL) {
2467 set_error(writer.error());
2468 if (out != NULL) {
2469 out->print_cr("Unable to create %s: %s", path,
2470 (error() != NULL) ? error() : "reason unknown");
2471 }
2472 return -1;
2473 }
2474
2475 // generate the dump
2476 VM_HeapDumper dumper(&writer, _gc_before_heap_dump, _oome, num_dump_threads);
2477 if (Thread::current()->is_VM_thread()) {
2478 assert(SafepointSynchronize::is_at_safepoint(), "Expected to be called at a safepoint");
2479 dumper.doit();
2480 } else {
2481 VMThread::execute(&dumper);
2482 }
2483
2484 // record any error that the writer may have encountered
2485 set_error(writer.error());
2486
2487 // emit JFR event
2488 if (error() == NULL) {
2489 event.set_destination(path);
2490 event.set_gcBeforeDump(_gc_before_heap_dump);
2491 event.set_size(writer.bytes_written());
2492 event.set_onOutOfMemoryError(_oome);
2493 event.commit();
2494 }
2495
2496 // print message in interactive case
2497 if (out != NULL) {
2498 timer()->stop();
2499 if (error() == NULL) {
2500 out->print_cr("Heap dump file created [" JULONG_FORMAT " bytes in %3.3f secs]",
2501 writer.bytes_written(), timer()->seconds());
2502 } else {
2503 out->print_cr("Dump file is incomplete: %s", writer.error());
2504 }
2505 }
2506
2507 return (writer.error() == NULL) ? 0 : -1;
2508 }
2509
2510 // stop timer (if still active), and free any error string we might be holding
2511 HeapDumper::~HeapDumper() {
2512 if (timer()->is_active()) {
2513 timer()->stop();
2514 }
2515 set_error(NULL);
2516 }
2517
2518
2519 // returns the error string (resource allocated), or NULL
2520 char* HeapDumper::error_as_C_string() const {
2521 if (error() != NULL) {
2522 char* str = NEW_RESOURCE_ARRAY(char, strlen(error())+1);
2523 strcpy(str, error());
2524 return str;
2525 } else {
2526 return NULL;
2527 }
2528 }
2529
2530 // set the error string
2531 void HeapDumper::set_error(char const* error) {
2532 if (_error != NULL) {
2533 os::free(_error);
2534 }
2535 if (error == NULL) {
2536 _error = NULL;
2537 } else {
2538 _error = os::strdup(error);
2539 assert(_error != NULL, "allocation failure");
2540 }
2541 }
2542
2543 // Called by out-of-memory error reporting by a single Java thread
2544 // outside of a JVM safepoint
2545 void HeapDumper::dump_heap_from_oome() {
2546 HeapDumper::dump_heap(true);
2547 }
2548
2549 // Called by error reporting by a single Java thread outside of a JVM safepoint,
2550 // or by heap dumping by the VM thread during a (GC) safepoint. Thus, these various
2551 // callers are strictly serialized and guaranteed not to interfere below. For more
2552 // general use, however, this method will need modification to prevent
2553 // inteference when updating the static variables base_path and dump_file_seq below.
2554 void HeapDumper::dump_heap() {
2555 HeapDumper::dump_heap(false);
2556 }
2557
2558 void HeapDumper::dump_heap(bool oome) {
2559 static char base_path[JVM_MAXPATHLEN] = {'\0'};
2560 static uint dump_file_seq = 0;
2561 char* my_path;
2562 const int max_digit_chars = 20;
2563
2564 const char* dump_file_name = "java_pid";
2565 const char* dump_file_ext = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
2566
2567 // The dump file defaults to java_pid<pid>.hprof in the current working
2568 // directory. HeapDumpPath=<file> can be used to specify an alternative
2569 // dump file name or a directory where dump file is created.
2570 if (dump_file_seq == 0) { // first time in, we initialize base_path
2571 // Calculate potentially longest base path and check if we have enough
2572 // allocated statically.
2573 const size_t total_length =
2574 (HeapDumpPath == NULL ? 0 : strlen(HeapDumpPath)) +
2575 strlen(os::file_separator()) + max_digit_chars +
2576 strlen(dump_file_name) + strlen(dump_file_ext) + 1;
2577 if (total_length > sizeof(base_path)) {
2578 warning("Cannot create heap dump file. HeapDumpPath is too long.");
2579 return;
2580 }
2581
2582 bool use_default_filename = true;
2583 if (HeapDumpPath == NULL || HeapDumpPath[0] == '\0') {
2584 // HeapDumpPath=<file> not specified
2585 } else {
2586 strcpy(base_path, HeapDumpPath);
2587 // check if the path is a directory (must exist)
2588 DIR* dir = os::opendir(base_path);
2589 if (dir == NULL) {
2590 use_default_filename = false;
2591 } else {
2592 // HeapDumpPath specified a directory. We append a file separator
2593 // (if needed).
2594 os::closedir(dir);
2595 size_t fs_len = strlen(os::file_separator());
2596 if (strlen(base_path) >= fs_len) {
2597 char* end = base_path;
2598 end += (strlen(base_path) - fs_len);
2599 if (strcmp(end, os::file_separator()) != 0) {
2600 strcat(base_path, os::file_separator());
2601 }
2602 }
2603 }
2604 }
2605 // If HeapDumpPath wasn't a file name then we append the default name
2606 if (use_default_filename) {
2607 const size_t dlen = strlen(base_path); // if heap dump dir specified
2608 jio_snprintf(&base_path[dlen], sizeof(base_path)-dlen, "%s%d%s",
2609 dump_file_name, os::current_process_id(), dump_file_ext);
2610 }
2611 const size_t len = strlen(base_path) + 1;
2612 my_path = (char*)os::malloc(len, mtInternal);
2613 if (my_path == NULL) {
2614 warning("Cannot create heap dump file. Out of system memory.");
2615 return;
2616 }
2617 strncpy(my_path, base_path, len);
2618 } else {
2619 // Append a sequence number id for dumps following the first
2620 const size_t len = strlen(base_path) + max_digit_chars + 2; // for '.' and \0
2621 my_path = (char*)os::malloc(len, mtInternal);
2622 if (my_path == NULL) {
2623 warning("Cannot create heap dump file. Out of system memory.");
2624 return;
2625 }
2626 jio_snprintf(my_path, len, "%s.%d", base_path, dump_file_seq);
2627 }
2628 dump_file_seq++; // increment seq number for next time we dump
2629
2630 HeapDumper dumper(false /* no GC before heap dump */,
2631 oome /* pass along out-of-memory-error flag */);
2632 dumper.dump(my_path, tty, HeapDumpGzipLevel);
2633 os::free(my_path);
2634 }