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/*
* Copyright (c) 2005, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "classfile/classLoaderData.inline.hpp"
#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/vmClasses.hpp"
#include "classfile/vmSymbols.hpp"
#include "gc/shared/gcLocker.hpp"
#include "gc/shared/gcVMOperations.hpp"
#include "gc/shared/workerThread.hpp"
#include "jfr/jfrEvents.hpp"
#include "jvm.h"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "oops/klass.inline.hpp"
#include "oops/objArrayKlass.hpp"
#include "oops/objArrayOop.inline.hpp"
#include "oops/oop.inline.hpp"
#include "oops/typeArrayOop.inline.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/javaThread.inline.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/os.hpp"
#include "runtime/reflectionUtils.hpp"
#include "runtime/threads.hpp"
#include "runtime/threadSMR.hpp"
#include "runtime/vframe.hpp"
#include "runtime/vmOperations.hpp"
#include "runtime/vmThread.hpp"
#include "services/heapDumper.hpp"
#include "services/heapDumperCompression.hpp"
#include "services/threadService.hpp"
#include "utilities/macros.hpp"
#include "utilities/ostream.hpp"
/*
* HPROF binary format - description copied from:
* src/share/demo/jvmti/hprof/hprof_io.c
*
*
* header "JAVA PROFILE 1.0.2" (0-terminated)
*
* u4 size of identifiers. Identifiers are used to represent
* UTF8 strings, objects, stack traces, etc. They usually
* have the same size as host pointers.
* u4 high word
* u4 low word number of milliseconds since 0:00 GMT, 1/1/70
* [record]* a sequence of records.
*
*
* Record format:
*
* u1 a TAG denoting the type of the record
* u4 number of *microseconds* since the time stamp in the
* header. (wraps around in a little more than an hour)
* u4 number of bytes *remaining* in the record. Note that
* this number excludes the tag and the length field itself.
* [u1]* BODY of the record (a sequence of bytes)
*
*
* The following TAGs are supported:
*
* TAG BODY notes
*----------------------------------------------------------
* HPROF_UTF8 a UTF8-encoded name
*
* id name ID
* [u1]* UTF8 characters (no trailing zero)
*
* HPROF_LOAD_CLASS a newly loaded class
*
* u4 class serial number (> 0)
* id class object ID
* u4 stack trace serial number
* id class name ID
*
* HPROF_UNLOAD_CLASS an unloading class
*
* u4 class serial_number
*
* HPROF_FRAME a Java stack frame
*
* id stack frame ID
* id method name ID
* id method signature ID
* id source file name ID
* u4 class serial number
* i4 line number. >0: normal
* -1: unknown
* -2: compiled method
* -3: native method
*
* HPROF_TRACE a Java stack trace
*
* u4 stack trace serial number
* u4 thread serial number
* u4 number of frames
* [id]* stack frame IDs
*
*
* HPROF_ALLOC_SITES a set of heap allocation sites, obtained after GC
*
* u2 flags 0x0001: incremental vs. complete
* 0x0002: sorted by allocation vs. live
* 0x0004: whether to force a GC
* u4 cutoff ratio
* u4 total live bytes
* u4 total live instances
* u8 total bytes allocated
* u8 total instances allocated
* u4 number of sites that follow
* [u1 is_array: 0: normal object
* 2: object array
* 4: boolean array
* 5: char array
* 6: float array
* 7: double array
* 8: byte array
* 9: short array
* 10: int array
* 11: long array
* u4 class serial number (may be zero during startup)
* u4 stack trace serial number
* u4 number of bytes alive
* u4 number of instances alive
* u4 number of bytes allocated
* u4]* number of instance allocated
*
* HPROF_START_THREAD a newly started thread.
*
* u4 thread serial number (> 0)
* id thread object ID
* u4 stack trace serial number
* id thread name ID
* id thread group name ID
* id thread group parent name ID
*
* HPROF_END_THREAD a terminating thread.
*
* u4 thread serial number
*
* HPROF_HEAP_SUMMARY heap summary
*
* u4 total live bytes
* u4 total live instances
* u8 total bytes allocated
* u8 total instances allocated
*
* HPROF_HEAP_DUMP denote a heap dump
*
* [heap dump sub-records]*
*
* There are four kinds of heap dump sub-records:
*
* u1 sub-record type
*
* HPROF_GC_ROOT_UNKNOWN unknown root
*
* id object ID
*
* HPROF_GC_ROOT_THREAD_OBJ thread object
*
* id thread object ID (may be 0 for a
* thread newly attached through JNI)
* u4 thread sequence number
* u4 stack trace sequence number
*
* HPROF_GC_ROOT_JNI_GLOBAL JNI global ref root
*
* id object ID
* id JNI global ref ID
*
* HPROF_GC_ROOT_JNI_LOCAL JNI local ref
*
* id object ID
* u4 thread serial number
* u4 frame # in stack trace (-1 for empty)
*
* HPROF_GC_ROOT_JAVA_FRAME Java stack frame
*
* id object ID
* u4 thread serial number
* u4 frame # in stack trace (-1 for empty)
*
* HPROF_GC_ROOT_NATIVE_STACK Native stack
*
* id object ID
* u4 thread serial number
*
* HPROF_GC_ROOT_STICKY_CLASS System class
*
* id object ID
*
* HPROF_GC_ROOT_THREAD_BLOCK Reference from thread block
*
* id object ID
* u4 thread serial number
*
* HPROF_GC_ROOT_MONITOR_USED Busy monitor
*
* id object ID
*
* HPROF_GC_CLASS_DUMP dump of a class object
*
* id class object ID
* u4 stack trace serial number
* id super class object ID
* id class loader object ID
* id signers object ID
* id protection domain object ID
* id reserved
* id reserved
*
* u4 instance size (in bytes)
*
* u2 size of constant pool
* [u2, constant pool index,
* ty, type
* 2: object
* 4: boolean
* 5: char
* 6: float
* 7: double
* 8: byte
* 9: short
* 10: int
* 11: long
* vl]* and value
*
* u2 number of static fields
* [id, static field name,
* ty, type,
* vl]* and value
*
* u2 number of inst. fields (not inc. super)
* [id, instance field name,
* ty]* type
*
* HPROF_GC_INSTANCE_DUMP dump of a normal object
*
* id object ID
* u4 stack trace serial number
* id class object ID
* u4 number of bytes that follow
* [vl]* instance field values (class, followed
* by super, super's super ...)
*
* HPROF_GC_OBJ_ARRAY_DUMP dump of an object array
*
* id array object ID
* u4 stack trace serial number
* u4 number of elements
* id array class ID
* [id]* elements
*
* HPROF_GC_PRIM_ARRAY_DUMP dump of a primitive array
*
* id array object ID
* u4 stack trace serial number
* u4 number of elements
* u1 element type
* 4: boolean array
* 5: char array
* 6: float array
* 7: double array
* 8: byte array
* 9: short array
* 10: int array
* 11: long array
* [u1]* elements
*
* HPROF_CPU_SAMPLES a set of sample traces of running threads
*
* u4 total number of samples
* u4 # of traces
* [u4 # of samples
* u4]* stack trace serial number
*
* HPROF_CONTROL_SETTINGS the settings of on/off switches
*
* u4 0x00000001: alloc traces on/off
* 0x00000002: cpu sampling on/off
* u2 stack trace depth
*
*
* When the header is "JAVA PROFILE 1.0.2" a heap dump can optionally
* be generated as a sequence of heap dump segments. This sequence is
* terminated by an end record. The additional tags allowed by format
* "JAVA PROFILE 1.0.2" are:
*
* HPROF_HEAP_DUMP_SEGMENT denote a heap dump segment
*
* [heap dump sub-records]*
* The same sub-record types allowed by HPROF_HEAP_DUMP
*
* HPROF_HEAP_DUMP_END denotes the end of a heap dump
*
*/
// HPROF tags
enum hprofTag : u1 {
// top-level records
HPROF_UTF8 = 0x01,
HPROF_LOAD_CLASS = 0x02,
HPROF_UNLOAD_CLASS = 0x03,
HPROF_FRAME = 0x04,
HPROF_TRACE = 0x05,
HPROF_ALLOC_SITES = 0x06,
HPROF_HEAP_SUMMARY = 0x07,
HPROF_START_THREAD = 0x0A,
HPROF_END_THREAD = 0x0B,
HPROF_HEAP_DUMP = 0x0C,
HPROF_CPU_SAMPLES = 0x0D,
HPROF_CONTROL_SETTINGS = 0x0E,
// 1.0.2 record types
HPROF_HEAP_DUMP_SEGMENT = 0x1C,
HPROF_HEAP_DUMP_END = 0x2C,
// field types
HPROF_ARRAY_OBJECT = 0x01,
HPROF_NORMAL_OBJECT = 0x02,
HPROF_BOOLEAN = 0x04,
HPROF_CHAR = 0x05,
HPROF_FLOAT = 0x06,
HPROF_DOUBLE = 0x07,
HPROF_BYTE = 0x08,
HPROF_SHORT = 0x09,
HPROF_INT = 0x0A,
HPROF_LONG = 0x0B,
// data-dump sub-records
HPROF_GC_ROOT_UNKNOWN = 0xFF,
HPROF_GC_ROOT_JNI_GLOBAL = 0x01,
HPROF_GC_ROOT_JNI_LOCAL = 0x02,
HPROF_GC_ROOT_JAVA_FRAME = 0x03,
HPROF_GC_ROOT_NATIVE_STACK = 0x04,
HPROF_GC_ROOT_STICKY_CLASS = 0x05,
HPROF_GC_ROOT_THREAD_BLOCK = 0x06,
HPROF_GC_ROOT_MONITOR_USED = 0x07,
HPROF_GC_ROOT_THREAD_OBJ = 0x08,
HPROF_GC_CLASS_DUMP = 0x20,
HPROF_GC_INSTANCE_DUMP = 0x21,
HPROF_GC_OBJ_ARRAY_DUMP = 0x22,
HPROF_GC_PRIM_ARRAY_DUMP = 0x23
};
// Default stack trace ID (used for dummy HPROF_TRACE record)
enum {
STACK_TRACE_ID = 1,
INITIAL_CLASS_COUNT = 200
};
// Supports I/O operations for a dump
// Base class for dump and parallel dump
class AbstractDumpWriter : public StackObj {
protected:
enum {
io_buffer_max_size = 1*M,
io_buffer_max_waste = 10*K,
dump_segment_header_size = 9
};
char* _buffer; // internal buffer
size_t _size;
size_t _pos;
bool _in_dump_segment; // Are we currently in a dump segment?
bool _is_huge_sub_record; // Are we writing a sub-record larger than the buffer size?
DEBUG_ONLY(size_t _sub_record_left;) // The bytes not written for the current sub-record.
DEBUG_ONLY(bool _sub_record_ended;) // True if we have called the end_sub_record().
virtual void flush(bool force = false) = 0;
char* buffer() const { return _buffer; }
size_t buffer_size() const { return _size; }
void set_position(size_t pos) { _pos = pos; }
// Can be called if we have enough room in the buffer.
void write_fast(const void* s, size_t len);
// Returns true if we have enough room in the buffer for 'len' bytes.
bool can_write_fast(size_t len);
void write_address(address a);
public:
AbstractDumpWriter() :
_buffer(NULL),
_size(io_buffer_max_size),
_pos(0),
_in_dump_segment(false) { }
// total number of bytes written to the disk
virtual julong bytes_written() const = 0;
virtual char const* error() const = 0;
size_t position() const { return _pos; }
// writer functions
virtual void write_raw(const void* s, size_t len);
void write_u1(u1 x);
void write_u2(u2 x);
void write_u4(u4 x);
void write_u8(u8 x);
void write_objectID(oop o);
void write_rootID(oop* p);
void write_symbolID(Symbol* o);
void write_classID(Klass* k);
void write_id(u4 x);
// Start a new sub-record. Starts a new heap dump segment if needed.
void start_sub_record(u1 tag, u4 len);
// Ends the current sub-record.
void end_sub_record();
// Finishes the current dump segment if not already finished.
void finish_dump_segment(bool force_flush = false);
// Refresh to get new buffer
void refresh() {
assert (_in_dump_segment ==false, "Sanity check");
_buffer = NULL;
_size = io_buffer_max_size;
_pos = 0;
// Force flush to guarantee data from parallel dumper are written.
flush(true);
}
// Called when finished to release the threads.
virtual void deactivate() = 0;
};
void AbstractDumpWriter::write_fast(const void* s, size_t len) {
assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
assert(buffer_size() - position() >= len, "Must fit");
debug_only(_sub_record_left -= len);
memcpy(buffer() + position(), s, len);
set_position(position() + len);
}
bool AbstractDumpWriter::can_write_fast(size_t len) {
return buffer_size() - position() >= len;
}
// write raw bytes
void AbstractDumpWriter::write_raw(const void* s, size_t len) {
assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
debug_only(_sub_record_left -= len);
// flush buffer to make room.
while (len > buffer_size() - position()) {
assert(!_in_dump_segment || _is_huge_sub_record,
"Cannot overflow in non-huge sub-record.");
size_t to_write = buffer_size() - position();
memcpy(buffer() + position(), s, to_write);
s = (void*) ((char*) s + to_write);
len -= to_write;
set_position(position() + to_write);
flush();
}
memcpy(buffer() + position(), s, len);
set_position(position() + len);
}
// Makes sure we inline the fast write into the write_u* functions. This is a big speedup.
#define WRITE_KNOWN_TYPE(p, len) do { if (can_write_fast((len))) write_fast((p), (len)); \
else write_raw((p), (len)); } while (0)
void AbstractDumpWriter::write_u1(u1 x) {
WRITE_KNOWN_TYPE(&x, 1);
}
void AbstractDumpWriter::write_u2(u2 x) {
u2 v;
Bytes::put_Java_u2((address)&v, x);
WRITE_KNOWN_TYPE(&v, 2);
}
void AbstractDumpWriter::write_u4(u4 x) {
u4 v;
Bytes::put_Java_u4((address)&v, x);
WRITE_KNOWN_TYPE(&v, 4);
}
void AbstractDumpWriter::write_u8(u8 x) {
u8 v;
Bytes::put_Java_u8((address)&v, x);
WRITE_KNOWN_TYPE(&v, 8);
}
void AbstractDumpWriter::write_address(address a) {
#ifdef _LP64
write_u8((u8)a);
#else
write_u4((u4)a);
#endif
}
void AbstractDumpWriter::write_objectID(oop o) {
write_address(cast_from_oop<address>(o));
}
void AbstractDumpWriter::write_rootID(oop* p) {
write_address((address)p);
}
void AbstractDumpWriter::write_symbolID(Symbol* s) {
write_address((address)((uintptr_t)s));
}
void AbstractDumpWriter::write_id(u4 x) {
#ifdef _LP64
write_u8((u8) x);
#else
write_u4(x);
#endif
}
// We use java mirror as the class ID
void AbstractDumpWriter::write_classID(Klass* k) {
write_objectID(k->java_mirror());
}
void AbstractDumpWriter::finish_dump_segment(bool force_flush) {
if (_in_dump_segment) {
assert(_sub_record_left == 0, "Last sub-record not written completely");
assert(_sub_record_ended, "sub-record must have ended");
// Fix up the dump segment length if we haven't written a huge sub-record last
// (in which case the segment length was already set to the correct value initially).
if (!_is_huge_sub_record) {
assert(position() > dump_segment_header_size, "Dump segment should have some content");
Bytes::put_Java_u4((address) (buffer() + 5),
(u4) (position() - dump_segment_header_size));
} else {
// Finish process huge sub record
// Set _is_huge_sub_record to false so the parallel dump writer can flush data to file.
_is_huge_sub_record = false;
}
_in_dump_segment = false;
flush(force_flush);
}
}
void AbstractDumpWriter::start_sub_record(u1 tag, u4 len) {
if (!_in_dump_segment) {
if (position() > 0) {
flush();
}
assert(position() == 0 && buffer_size() > dump_segment_header_size, "Must be at the start");
write_u1(HPROF_HEAP_DUMP_SEGMENT);
write_u4(0); // timestamp
// Will be fixed up later if we add more sub-records. If this is a huge sub-record,
// this is already the correct length, since we don't add more sub-records.
write_u4(len);
assert(Bytes::get_Java_u4((address)(buffer() + 5)) == len, "Inconsistent size!");
_in_dump_segment = true;
_is_huge_sub_record = len > buffer_size() - dump_segment_header_size;
} else if (_is_huge_sub_record || (len > buffer_size() - position())) {
// This object will not fit in completely or the last sub-record was huge.
// Finish the current segment and try again.
finish_dump_segment();
start_sub_record(tag, len);
return;
}
debug_only(_sub_record_left = len);
debug_only(_sub_record_ended = false);
write_u1(tag);
}
void AbstractDumpWriter::end_sub_record() {
assert(_in_dump_segment, "must be in dump segment");
assert(_sub_record_left == 0, "sub-record not written completely");
assert(!_sub_record_ended, "Must not have ended yet");
debug_only(_sub_record_ended = true);
}
// Supports I/O operations for a dump
class DumpWriter : public AbstractDumpWriter {
private:
CompressionBackend _backend; // Does the actual writing.
protected:
void flush(bool force = false) override;
public:
// Takes ownership of the writer and compressor.
DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor);
// total number of bytes written to the disk
julong bytes_written() const override { return (julong) _backend.get_written(); }
char const* error() const override { return _backend.error(); }
// Called by threads used for parallel writing.
void writer_loop() { _backend.thread_loop(); }
// Called when finish to release the threads.
void deactivate() override { flush(); _backend.deactivate(); }
// Get the backend pointer, used by parallel dump writer.
CompressionBackend* backend_ptr() { return &_backend; }
};
// Check for error after constructing the object and destroy it in case of an error.
DumpWriter::DumpWriter(AbstractWriter* writer, AbstractCompressor* compressor) :
AbstractDumpWriter(),
_backend(writer, compressor, io_buffer_max_size, io_buffer_max_waste) {
flush();
}
// flush any buffered bytes to the file
void DumpWriter::flush(bool force) {
_backend.get_new_buffer(&_buffer, &_pos, &_size, force);
}
// Buffer queue used for parallel dump.
struct ParWriterBufferQueueElem {
char* _buffer;
size_t _used;
ParWriterBufferQueueElem* _next;
};
class ParWriterBufferQueue : public CHeapObj<mtInternal> {
private:
ParWriterBufferQueueElem* _head;
ParWriterBufferQueueElem* _tail;
uint _length;
public:
ParWriterBufferQueue() : _head(NULL), _tail(NULL), _length(0) { }
void enqueue(ParWriterBufferQueueElem* entry) {
if (_head == NULL) {
assert(is_empty() && _tail == NULL, "Sanity check");
_head = _tail = entry;
} else {
assert ((_tail->_next == NULL && _tail->_buffer != NULL), "Buffer queue is polluted");
_tail->_next = entry;
_tail = entry;
}
_length++;
assert(_tail->_next == NULL, "Buffer queue is polluted");
}
ParWriterBufferQueueElem* dequeue() {
if (_head == NULL) return NULL;
ParWriterBufferQueueElem* entry = _head;
assert (entry->_buffer != NULL, "polluted buffer in writer list");
_head = entry->_next;
if (_head == NULL) {
_tail = NULL;
}
entry->_next = NULL;
_length--;
return entry;
}
bool is_empty() {
return _length == 0;
}
uint length() { return _length; }
};
// Support parallel heap dump.
class ParDumpWriter : public AbstractDumpWriter {
private:
// Lock used to guarantee the integrity of multiple buffers writing.
static Monitor* _lock;
// Pointer of backend from global DumpWriter.
CompressionBackend* _backend_ptr;
char const * _err;
ParWriterBufferQueue* _buffer_queue;
size_t _internal_buffer_used;
char* _buffer_base;
bool _split_data;
static const uint BackendFlushThreshold = 2;
protected:
void flush(bool force = false) override {
assert(_pos != 0, "must not be zero");
if (_pos != 0) {
refresh_buffer();
}
if (_split_data || _is_huge_sub_record) {
return;
}
if (should_flush_buf_list(force)) {
assert(!_in_dump_segment && !_split_data && !_is_huge_sub_record, "incomplete data send to backend!\n");
flush_to_backend(force);
}
}
public:
// Check for error after constructing the object and destroy it in case of an error.
ParDumpWriter(DumpWriter* dw) :
AbstractDumpWriter(),
_backend_ptr(dw->backend_ptr()),
_buffer_queue((new (std::nothrow) ParWriterBufferQueue())),
_buffer_base(NULL),
_split_data(false) {
// prepare internal buffer
allocate_internal_buffer();
}
~ParDumpWriter() {
assert(_buffer_queue != NULL, "Sanity check");
assert((_internal_buffer_used == 0) && (_buffer_queue->is_empty()),
"All data must be send to backend");
if (_buffer_base != NULL) {
os::free(_buffer_base);
_buffer_base = NULL;
}
delete _buffer_queue;
_buffer_queue = NULL;
}
// total number of bytes written to the disk
julong bytes_written() const override { return (julong) _backend_ptr->get_written(); }
char const* error() const override { return _err == NULL ? _backend_ptr->error() : _err; }
static void before_work() {
assert(_lock == NULL, "ParDumpWriter lock must be initialized only once");
_lock = new (std::nothrow) PaddedMonitor(Mutex::safepoint, "ParallelHProfWriter_lock");
}
static void after_work() {
assert(_lock != NULL, "ParDumpWriter lock is not initialized");
delete _lock;
_lock = NULL;
}
// write raw bytes
void write_raw(const void* s, size_t len) override {
assert(!_in_dump_segment || (_sub_record_left >= len), "sub-record too large");
debug_only(_sub_record_left -= len);
assert(!_split_data, "Invalid split data");
_split_data = true;
// flush buffer to make room.
while (len > buffer_size() - position()) {
assert(!_in_dump_segment || _is_huge_sub_record,
"Cannot overflow in non-huge sub-record.");
size_t to_write = buffer_size() - position();
memcpy(buffer() + position(), s, to_write);
s = (void*) ((char*) s + to_write);
len -= to_write;
set_position(position() + to_write);
flush();
}
_split_data = false;
memcpy(buffer() + position(), s, len);
set_position(position() + len);
}
void deactivate() override { flush(true); _backend_ptr->deactivate(); }
private:
void allocate_internal_buffer() {
assert(_buffer_queue != NULL, "Internal buffer queue is not ready when allocate internal buffer");
assert(_buffer == NULL && _buffer_base == NULL, "current buffer must be NULL before allocate");
_buffer_base = _buffer = (char*)os::malloc(io_buffer_max_size, mtInternal);
if (_buffer == NULL) {
set_error("Could not allocate buffer for writer");
return;
}
_pos = 0;
_internal_buffer_used = 0;
_size = io_buffer_max_size;
}
void set_error(char const* new_error) {
if ((new_error != NULL) && (_err == NULL)) {
_err = new_error;
}
}
// Add buffer to internal list
void refresh_buffer() {
size_t expected_total = _internal_buffer_used + _pos;
if (expected_total < io_buffer_max_size - io_buffer_max_waste) {
// reuse current buffer.
_internal_buffer_used = expected_total;
assert(_size - _pos == io_buffer_max_size - expected_total, "illegal resize of buffer");
_size -= _pos;
_buffer += _pos;
_pos = 0;
return;
}
// It is not possible here that expected_total is larger than io_buffer_max_size because
// of limitation in write_xxx().
assert(expected_total <= io_buffer_max_size, "buffer overflow");
assert(_buffer - _buffer_base <= io_buffer_max_size, "internal buffer overflow");
ParWriterBufferQueueElem* entry =
(ParWriterBufferQueueElem*)os::malloc(sizeof(ParWriterBufferQueueElem), mtInternal);
if (entry == NULL) {
set_error("Heap dumper can allocate memory");
return;
}
entry->_buffer = _buffer_base;
entry->_used = expected_total;
entry->_next = NULL;
// add to internal buffer queue
_buffer_queue->enqueue(entry);
_buffer_base =_buffer = NULL;
allocate_internal_buffer();
}
void reclaim_entry(ParWriterBufferQueueElem* entry) {
assert(entry != NULL && entry->_buffer != NULL, "Invalid entry to reclaim");
os::free(entry->_buffer);
entry->_buffer = NULL;
os::free(entry);
}
void flush_buffer(char* buffer, size_t used) {
assert(_lock->owner() == Thread::current(), "flush buffer must hold lock");
size_t max = io_buffer_max_size;
// get_new_buffer
_backend_ptr->flush_external_buffer(buffer, used, max);
}
bool should_flush_buf_list(bool force) {
return force || _buffer_queue->length() > BackendFlushThreshold;
}
void flush_to_backend(bool force) {
// Guarantee there is only one writer updating the backend buffers.
MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
while (!_buffer_queue->is_empty()) {
ParWriterBufferQueueElem* entry = _buffer_queue->dequeue();
flush_buffer(entry->_buffer, entry->_used);
// Delete buffer and entry.
reclaim_entry(entry);
entry = NULL;
}
assert(_pos == 0, "available buffer must be empty before flush");
// Flush internal buffer.
if (_internal_buffer_used > 0) {
flush_buffer(_buffer_base, _internal_buffer_used);
os::free(_buffer_base);
_pos = 0;
_internal_buffer_used = 0;
_buffer_base = _buffer = NULL;
// Allocate internal buffer for future use.
allocate_internal_buffer();
}
}
};
Monitor* ParDumpWriter::_lock = NULL;
// Support class with a collection of functions used when dumping the heap
class DumperSupport : AllStatic {
public:
// write a header of the given type
static void write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len);
// returns hprof tag for the given type signature
static hprofTag sig2tag(Symbol* sig);
// returns hprof tag for the given basic type
static hprofTag type2tag(BasicType type);
// Returns the size of the data to write.
static u4 sig2size(Symbol* sig);
// returns the size of the instance of the given class
static u4 instance_size(Klass* k);
// dump a jfloat
static void dump_float(AbstractDumpWriter* writer, jfloat f);
// dump a jdouble
static void dump_double(AbstractDumpWriter* writer, jdouble d);
// dumps the raw value of the given field
static void dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset);
// returns the size of the static fields; also counts the static fields
static u4 get_static_fields_size(InstanceKlass* ik, u2& field_count);
// dumps static fields of the given class
static void dump_static_fields(AbstractDumpWriter* writer, Klass* k);
// dump the raw values of the instance fields of the given object
static void dump_instance_fields(AbstractDumpWriter* writer, oop o);
// get the count of the instance fields for a given class
static u2 get_instance_fields_count(InstanceKlass* ik);
// dumps the definition of the instance fields for a given class
static void dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k);
// creates HPROF_GC_INSTANCE_DUMP record for the given object
static void dump_instance(AbstractDumpWriter* writer, oop o);
// creates HPROF_GC_CLASS_DUMP record for the given instance class
static void dump_instance_class(AbstractDumpWriter* writer, Klass* k);
// creates HPROF_GC_CLASS_DUMP record for a given array class
static void dump_array_class(AbstractDumpWriter* writer, Klass* k);
// creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
static void dump_object_array(AbstractDumpWriter* writer, objArrayOop array);
// creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
static void dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array);
// create HPROF_FRAME record for the given method and bci
static void dump_stack_frame(AbstractDumpWriter* writer, int frame_serial_num, int class_serial_num, Method* m, int bci);
// check if we need to truncate an array
static int calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size);
// fixes up the current dump record and writes HPROF_HEAP_DUMP_END record
static void end_of_dump(AbstractDumpWriter* writer);
static oop mask_dormant_archived_object(oop o) {
if (o != NULL && o->klass()->java_mirror() == NULL) {
// Ignore this object since the corresponding java mirror is not loaded.
// Might be a dormant archive object.
return NULL;
} else {
return o;
}
}
};
// write a header of the given type
void DumperSupport:: write_header(AbstractDumpWriter* writer, hprofTag tag, u4 len) {
writer->write_u1(tag);
writer->write_u4(0); // current ticks
writer->write_u4(len);
}
// returns hprof tag for the given type signature
hprofTag DumperSupport::sig2tag(Symbol* sig) {
switch (sig->char_at(0)) {
case JVM_SIGNATURE_CLASS : return HPROF_NORMAL_OBJECT;
case JVM_SIGNATURE_ARRAY : return HPROF_NORMAL_OBJECT;
case JVM_SIGNATURE_BYTE : return HPROF_BYTE;
case JVM_SIGNATURE_CHAR : return HPROF_CHAR;
case JVM_SIGNATURE_FLOAT : return HPROF_FLOAT;
case JVM_SIGNATURE_DOUBLE : return HPROF_DOUBLE;
case JVM_SIGNATURE_INT : return HPROF_INT;
case JVM_SIGNATURE_LONG : return HPROF_LONG;
case JVM_SIGNATURE_SHORT : return HPROF_SHORT;
case JVM_SIGNATURE_BOOLEAN : return HPROF_BOOLEAN;
default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
}
}
hprofTag DumperSupport::type2tag(BasicType type) {
switch (type) {
case T_BYTE : return HPROF_BYTE;
case T_CHAR : return HPROF_CHAR;
case T_FLOAT : return HPROF_FLOAT;
case T_DOUBLE : return HPROF_DOUBLE;
case T_INT : return HPROF_INT;
case T_LONG : return HPROF_LONG;
case T_SHORT : return HPROF_SHORT;
case T_BOOLEAN : return HPROF_BOOLEAN;
default : ShouldNotReachHere(); /* to shut up compiler */ return HPROF_BYTE;
}
}
u4 DumperSupport::sig2size(Symbol* sig) {
switch (sig->char_at(0)) {
case JVM_SIGNATURE_CLASS:
case JVM_SIGNATURE_ARRAY: return sizeof(address);
case JVM_SIGNATURE_BOOLEAN:
case JVM_SIGNATURE_BYTE: return 1;
case JVM_SIGNATURE_SHORT:
case JVM_SIGNATURE_CHAR: return 2;
case JVM_SIGNATURE_INT:
case JVM_SIGNATURE_FLOAT: return 4;
case JVM_SIGNATURE_LONG:
case JVM_SIGNATURE_DOUBLE: return 8;
default: ShouldNotReachHere(); /* to shut up compiler */ return 0;
}
}
template<typename T, typename F> T bit_cast(F from) { // replace with the real thing when we can use c++20
T to;
static_assert(sizeof(to) == sizeof(from), "must be of the same size");
memcpy(&to, &from, sizeof(to));
return to;
}
// dump a jfloat
void DumperSupport::dump_float(AbstractDumpWriter* writer, jfloat f) {
if (g_isnan(f)) {
writer->write_u4(0x7fc00000); // collapsing NaNs
} else {
writer->write_u4(bit_cast<u4>(f));
}
}
// dump a jdouble
void DumperSupport::dump_double(AbstractDumpWriter* writer, jdouble d) {
if (g_isnan(d)) {
writer->write_u8(0x7ff80000ull << 32); // collapsing NaNs
} else {
writer->write_u8(bit_cast<u8>(d));
}
}
// dumps the raw value of the given field
void DumperSupport::dump_field_value(AbstractDumpWriter* writer, char type, oop obj, int offset) {
switch (type) {
case JVM_SIGNATURE_CLASS :
case JVM_SIGNATURE_ARRAY : {
oop o = obj->obj_field_access<ON_UNKNOWN_OOP_REF | AS_NO_KEEPALIVE>(offset);
if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
ResourceMark rm;
log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
p2i(o), o->klass()->external_name(),
p2i(obj), obj->klass()->external_name());
}
o = mask_dormant_archived_object(o);
assert(oopDesc::is_oop_or_null(o), "Expected an oop or NULL at " PTR_FORMAT, p2i(o));
writer->write_objectID(o);
break;
}
case JVM_SIGNATURE_BYTE : {
jbyte b = obj->byte_field(offset);
writer->write_u1(b);
break;
}
case JVM_SIGNATURE_CHAR : {
jchar c = obj->char_field(offset);
writer->write_u2(c);
break;
}
case JVM_SIGNATURE_SHORT : {
jshort s = obj->short_field(offset);
writer->write_u2(s);
break;
}
case JVM_SIGNATURE_FLOAT : {
jfloat f = obj->float_field(offset);
dump_float(writer, f);
break;
}
case JVM_SIGNATURE_DOUBLE : {
jdouble d = obj->double_field(offset);
dump_double(writer, d);
break;
}
case JVM_SIGNATURE_INT : {
jint i = obj->int_field(offset);
writer->write_u4(i);
break;
}
case JVM_SIGNATURE_LONG : {
jlong l = obj->long_field(offset);
writer->write_u8(l);
break;
}
case JVM_SIGNATURE_BOOLEAN : {
jboolean b = obj->bool_field(offset);
writer->write_u1(b);
break;
}
default : {
ShouldNotReachHere();
break;
}
}
}
// returns the size of the instance of the given class
u4 DumperSupport::instance_size(Klass* k) {
InstanceKlass* ik = InstanceKlass::cast(k);
u4 size = 0;
for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
if (!fld.access_flags().is_static()) {
size += sig2size(fld.signature());
}
}
return size;
}
u4 DumperSupport::get_static_fields_size(InstanceKlass* ik, u2& field_count) {
field_count = 0;
u4 size = 0;
for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
if (fldc.access_flags().is_static()) {
field_count++;
size += sig2size(fldc.signature());
}
}
// Add in resolved_references which is referenced by the cpCache
// The resolved_references is an array per InstanceKlass holding the
// strings and other oops resolved from the constant pool.
oop resolved_references = ik->constants()->resolved_references_or_null();
if (resolved_references != NULL) {
field_count++;
size += sizeof(address);
// Add in the resolved_references of the used previous versions of the class
// in the case of RedefineClasses
InstanceKlass* prev = ik->previous_versions();
while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
field_count++;
size += sizeof(address);
prev = prev->previous_versions();
}
}
// We write the value itself plus a name and a one byte type tag per field.
return size + field_count * (sizeof(address) + 1);
}
// dumps static fields of the given class
void DumperSupport::dump_static_fields(AbstractDumpWriter* writer, Klass* k) {
InstanceKlass* ik = InstanceKlass::cast(k);
// dump the field descriptors and raw values
for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
if (fld.access_flags().is_static()) {
Symbol* sig = fld.signature();
writer->write_symbolID(fld.name()); // name
writer->write_u1(sig2tag(sig)); // type
// value
dump_field_value(writer, sig->char_at(0), ik->java_mirror(), fld.offset());
}
}
// Add resolved_references for each class that has them
oop resolved_references = ik->constants()->resolved_references_or_null();
if (resolved_references != NULL) {
writer->write_symbolID(vmSymbols::resolved_references_name()); // name
writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
writer->write_objectID(resolved_references);
// Also write any previous versions
InstanceKlass* prev = ik->previous_versions();
while (prev != NULL && prev->constants()->resolved_references_or_null() != NULL) {
writer->write_symbolID(vmSymbols::resolved_references_name()); // name
writer->write_u1(sig2tag(vmSymbols::object_array_signature())); // type
writer->write_objectID(prev->constants()->resolved_references());
prev = prev->previous_versions();
}
}
}
// dump the raw values of the instance fields of the given object
void DumperSupport::dump_instance_fields(AbstractDumpWriter* writer, oop o) {
InstanceKlass* ik = InstanceKlass::cast(o->klass());
for (FieldStream fld(ik, false, false); !fld.eos(); fld.next()) {
if (!fld.access_flags().is_static()) {
Symbol* sig = fld.signature();
dump_field_value(writer, sig->char_at(0), o, fld.offset());
}
}
}
// dumps the definition of the instance fields for a given class
u2 DumperSupport::get_instance_fields_count(InstanceKlass* ik) {
u2 field_count = 0;
for (FieldStream fldc(ik, true, true); !fldc.eos(); fldc.next()) {
if (!fldc.access_flags().is_static()) field_count++;
}
return field_count;
}
// dumps the definition of the instance fields for a given class
void DumperSupport::dump_instance_field_descriptors(AbstractDumpWriter* writer, Klass* k) {
InstanceKlass* ik = InstanceKlass::cast(k);
// dump the field descriptors
for (FieldStream fld(ik, true, true); !fld.eos(); fld.next()) {
if (!fld.access_flags().is_static()) {
Symbol* sig = fld.signature();
writer->write_symbolID(fld.name()); // name
writer->write_u1(sig2tag(sig)); // type
}
}
}
// creates HPROF_GC_INSTANCE_DUMP record for the given object
void DumperSupport::dump_instance(AbstractDumpWriter* writer, oop o) {
InstanceKlass* ik = InstanceKlass::cast(o->klass());
u4 is = instance_size(ik);
u4 size = 1 + sizeof(address) + 4 + sizeof(address) + 4 + is;
writer->start_sub_record(HPROF_GC_INSTANCE_DUMP, size);
writer->write_objectID(o);
writer->write_u4(STACK_TRACE_ID);
// class ID
writer->write_classID(ik);
// number of bytes that follow
writer->write_u4(is);
// field values
dump_instance_fields(writer, o);
writer->end_sub_record();
}
// creates HPROF_GC_CLASS_DUMP record for the given instance class
void DumperSupport::dump_instance_class(AbstractDumpWriter* writer, Klass* k) {
InstanceKlass* ik = InstanceKlass::cast(k);
// We can safepoint and do a heap dump at a point where we have a Klass,
// but no java mirror class has been setup for it. So we need to check
// that the class is at least loaded, to avoid crash from a null mirror.
if (!ik->is_loaded()) {
return;
}
u2 static_fields_count = 0;
u4 static_size = get_static_fields_size(ik, static_fields_count);
u2 instance_fields_count = get_instance_fields_count(ik);
u4 instance_fields_size = instance_fields_count * (sizeof(address) + 1);
u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + static_size + 2 + instance_fields_size;
writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
// class ID
writer->write_classID(ik);
writer->write_u4(STACK_TRACE_ID);
// super class ID
InstanceKlass* java_super = ik->java_super();
if (java_super == NULL) {
writer->write_objectID(oop(NULL));
} else {
writer->write_classID(java_super);
}
writer->write_objectID(ik->class_loader());
writer->write_objectID(ik->signers());
writer->write_objectID(ik->protection_domain());
// reserved
writer->write_objectID(oop(NULL));
writer->write_objectID(oop(NULL));
// instance size
writer->write_u4(DumperSupport::instance_size(ik));
// size of constant pool - ignored by HAT 1.1
writer->write_u2(0);
// static fields
writer->write_u2(static_fields_count);
dump_static_fields(writer, ik);
// description of instance fields
writer->write_u2(instance_fields_count);
dump_instance_field_descriptors(writer, ik);
writer->end_sub_record();
}
// creates HPROF_GC_CLASS_DUMP record for the given array class
void DumperSupport::dump_array_class(AbstractDumpWriter* writer, Klass* k) {
InstanceKlass* ik = NULL; // bottom class for object arrays, NULL for primitive type arrays
if (k->is_objArray_klass()) {
Klass *bk = ObjArrayKlass::cast(k)->bottom_klass();
assert(bk != NULL, "checking");
if (bk->is_instance_klass()) {
ik = InstanceKlass::cast(bk);
}
}
u4 size = 1 + sizeof(address) + 4 + 6 * sizeof(address) + 4 + 2 + 2 + 2;
writer->start_sub_record(HPROF_GC_CLASS_DUMP, size);
writer->write_classID(k);
writer->write_u4(STACK_TRACE_ID);
// super class of array classes is java.lang.Object
InstanceKlass* java_super = k->java_super();
assert(java_super != NULL, "checking");
writer->write_classID(java_super);
writer->write_objectID(ik == NULL ? oop(NULL) : ik->class_loader());
writer->write_objectID(ik == NULL ? oop(NULL) : ik->signers());
writer->write_objectID(ik == NULL ? oop(NULL) : ik->protection_domain());
writer->write_objectID(oop(NULL)); // reserved
writer->write_objectID(oop(NULL));
writer->write_u4(0); // instance size
writer->write_u2(0); // constant pool
writer->write_u2(0); // static fields
writer->write_u2(0); // instance fields
writer->end_sub_record();
}
// Hprof uses an u4 as record length field,
// which means we need to truncate arrays that are too long.
int DumperSupport::calculate_array_max_length(AbstractDumpWriter* writer, arrayOop array, short header_size) {
BasicType type = ArrayKlass::cast(array->klass())->element_type();
assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
int length = array->length();
int type_size;
if (type == T_OBJECT) {
type_size = sizeof(address);
} else {
type_size = type2aelembytes(type);
}
size_t length_in_bytes = (size_t)length * type_size;
uint max_bytes = max_juint - header_size;
if (length_in_bytes > max_bytes) {
length = max_bytes / type_size;
length_in_bytes = (size_t)length * type_size;
warning("cannot dump array of type %s[] with length %d; truncating to length %d",
type2name_tab[type], array->length(), length);
}
return length;
}
// creates HPROF_GC_OBJ_ARRAY_DUMP record for the given object array
void DumperSupport::dump_object_array(AbstractDumpWriter* writer, objArrayOop array) {
// sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID) + sizeof(classID)
short header_size = 1 + 2 * 4 + 2 * sizeof(address);
int length = calculate_array_max_length(writer, array, header_size);
u4 size = header_size + length * sizeof(address);
writer->start_sub_record(HPROF_GC_OBJ_ARRAY_DUMP, size);
writer->write_objectID(array);
writer->write_u4(STACK_TRACE_ID);
writer->write_u4(length);
// array class ID
writer->write_classID(array->klass());
// [id]* elements
for (int index = 0; index < length; index++) {
oop o = array->obj_at(index);
if (o != NULL && log_is_enabled(Debug, cds, heap) && mask_dormant_archived_object(o) == NULL) {
ResourceMark rm;
log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s) referenced by " INTPTR_FORMAT " (%s)",
p2i(o), o->klass()->external_name(),
p2i(array), array->klass()->external_name());
}
o = mask_dormant_archived_object(o);
writer->write_objectID(o);
}
writer->end_sub_record();
}
#define WRITE_ARRAY(Array, Type, Size, Length) \
for (int i = 0; i < Length; i++) { writer->write_##Size((Size)Array->Type##_at(i)); }
// creates HPROF_GC_PRIM_ARRAY_DUMP record for the given type array
void DumperSupport::dump_prim_array(AbstractDumpWriter* writer, typeArrayOop array) {
BasicType type = TypeArrayKlass::cast(array->klass())->element_type();
// 2 * sizeof(u1) + 2 * sizeof(u4) + sizeof(objectID)
short header_size = 2 * 1 + 2 * 4 + sizeof(address);
int length = calculate_array_max_length(writer, array, header_size);
int type_size = type2aelembytes(type);
u4 length_in_bytes = (u4)length * type_size;
u4 size = header_size + length_in_bytes;
writer->start_sub_record(HPROF_GC_PRIM_ARRAY_DUMP, size);
writer->write_objectID(array);
writer->write_u4(STACK_TRACE_ID);
writer->write_u4(length);
writer->write_u1(type2tag(type));
// nothing to copy
if (length == 0) {
writer->end_sub_record();
return;
}
// If the byte ordering is big endian then we can copy most types directly
switch (type) {
case T_INT : {
if (Endian::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, int, u4, length);
} else {
writer->write_raw(array->int_at_addr(0), length_in_bytes);
}
break;
}
case T_BYTE : {
writer->write_raw(array->byte_at_addr(0), length_in_bytes);
break;
}
case T_CHAR : {
if (Endian::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, char, u2, length);
} else {
writer->write_raw(array->char_at_addr(0), length_in_bytes);
}
break;
}
case T_SHORT : {
if (Endian::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, short, u2, length);
} else {
writer->write_raw(array->short_at_addr(0), length_in_bytes);
}
break;
}
case T_BOOLEAN : {
if (Endian::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, bool, u1, length);
} else {
writer->write_raw(array->bool_at_addr(0), length_in_bytes);
}
break;
}
case T_LONG : {
if (Endian::is_Java_byte_ordering_different()) {
WRITE_ARRAY(array, long, u8, length);
} else {
writer->write_raw(array->long_at_addr(0), length_in_bytes);
}
break;
}
// handle float/doubles in a special value to ensure than NaNs are
// written correctly. TO DO: Check if we can avoid this on processors that
// use IEEE 754.
case T_FLOAT : {
for (int i = 0; i < length; i++) {
dump_float(writer, array->float_at(i));
}
break;
}
case T_DOUBLE : {
for (int i = 0; i < length; i++) {
dump_double(writer, array->double_at(i));
}
break;
}
default : ShouldNotReachHere();
}
writer->end_sub_record();
}
// create a HPROF_FRAME record of the given Method* and bci
void DumperSupport::dump_stack_frame(AbstractDumpWriter* writer,
int frame_serial_num,
int class_serial_num,
Method* m,
int bci) {
int line_number;
if (m->is_native()) {
line_number = -3; // native frame
} else {
line_number = m->line_number_from_bci(bci);
}
write_header(writer, HPROF_FRAME, 4*oopSize + 2*sizeof(u4));
writer->write_id(frame_serial_num); // frame serial number
writer->write_symbolID(m->name()); // method's name
writer->write_symbolID(m->signature()); // method's signature
assert(m->method_holder()->is_instance_klass(), "not InstanceKlass");
writer->write_symbolID(m->method_holder()->source_file_name()); // source file name
writer->write_u4(class_serial_num); // class serial number
writer->write_u4((u4) line_number); // line number
}
// Support class used to generate HPROF_UTF8 records from the entries in the
// SymbolTable.
class SymbolTableDumper : public SymbolClosure {
private:
AbstractDumpWriter* _writer;
AbstractDumpWriter* writer() const { return _writer; }
public:
SymbolTableDumper(AbstractDumpWriter* writer) { _writer = writer; }
void do_symbol(Symbol** p);
};
void SymbolTableDumper::do_symbol(Symbol** p) {
ResourceMark rm;
Symbol* sym = *p;
int len = sym->utf8_length();
if (len > 0) {
char* s = sym->as_utf8();
DumperSupport::write_header(writer(), HPROF_UTF8, oopSize + len);
writer()->write_symbolID(sym);
writer()->write_raw(s, len);
}
}
// Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
class JNILocalsDumper : public OopClosure {
private:
AbstractDumpWriter* _writer;
u4 _thread_serial_num;
int _frame_num;
AbstractDumpWriter* writer() const { return _writer; }
public:
JNILocalsDumper(AbstractDumpWriter* writer, u4 thread_serial_num) {
_writer = writer;
_thread_serial_num = thread_serial_num;
_frame_num = -1; // default - empty stack
}
void set_frame_number(int n) { _frame_num = n; }
void do_oop(oop* obj_p);
void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
};
void JNILocalsDumper::do_oop(oop* obj_p) {
// ignore null handles
oop o = *obj_p;
if (o != NULL) {
u4 size = 1 + sizeof(address) + 4 + 4;
writer()->start_sub_record(HPROF_GC_ROOT_JNI_LOCAL, size);
writer()->write_objectID(o);
writer()->write_u4(_thread_serial_num);
writer()->write_u4((u4)_frame_num);
writer()->end_sub_record();
}
}
// Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
class JNIGlobalsDumper : public OopClosure {
private:
AbstractDumpWriter* _writer;
AbstractDumpWriter* writer() const { return _writer; }
public:
JNIGlobalsDumper(AbstractDumpWriter* writer) {
_writer = writer;
}
void do_oop(oop* obj_p);
void do_oop(narrowOop* obj_p) { ShouldNotReachHere(); }
};
void JNIGlobalsDumper::do_oop(oop* obj_p) {
oop o = NativeAccess<AS_NO_KEEPALIVE>::oop_load(obj_p);
// ignore these
if (o == NULL) return;
// we ignore global ref to symbols and other internal objects
if (o->is_instance() || o->is_objArray() || o->is_typeArray()) {
u4 size = 1 + 2 * sizeof(address);
writer()->start_sub_record(HPROF_GC_ROOT_JNI_GLOBAL, size);
writer()->write_objectID(o);
writer()->write_rootID(obj_p); // global ref ID
writer()->end_sub_record();
}
};
// Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
class StickyClassDumper : public KlassClosure {
private:
AbstractDumpWriter* _writer;
AbstractDumpWriter* writer() const { return _writer; }
public:
StickyClassDumper(AbstractDumpWriter* writer) {
_writer = writer;
}
void do_klass(Klass* k) {
if (k->is_instance_klass()) {
InstanceKlass* ik = InstanceKlass::cast(k);
u4 size = 1 + sizeof(address);
writer()->start_sub_record(HPROF_GC_ROOT_STICKY_CLASS, size);
writer()->write_classID(ik);
writer()->end_sub_record();
}
}
};
// Large object heap dump support.
// To avoid memory consumption, when dumping large objects such as huge array and
// large objects whose size are larger than LARGE_OBJECT_DUMP_THRESHOLD, the scanned
// partial object/array data will be sent to the backend directly instead of caching
// the whole object/array in the internal buffer.
// The HeapDumpLargeObjectList is used to save the large object when dumper scans
// the heap. The large objects could be added (push) parallelly by multiple dumpers,
// But they will be removed (popped) serially only by the VM thread.
class HeapDumpLargeObjectList : public CHeapObj<mtInternal> {
private:
class HeapDumpLargeObjectListElem : public CHeapObj<mtInternal> {
public:
HeapDumpLargeObjectListElem(oop obj) : _obj(obj), _next(NULL) { }
oop _obj;
HeapDumpLargeObjectListElem* _next;
};
volatile HeapDumpLargeObjectListElem* _head;
public:
HeapDumpLargeObjectList() : _head(NULL) { }
void atomic_push(oop obj) {
assert (obj != NULL, "sanity check");
HeapDumpLargeObjectListElem* entry = new HeapDumpLargeObjectListElem(obj);
if (entry == NULL) {
warning("failed to allocate element for large object list");
return;
}
assert (entry->_obj != NULL, "sanity check");
while (true) {
volatile HeapDumpLargeObjectListElem* old_head = Atomic::load_acquire(&_head);
HeapDumpLargeObjectListElem* new_head = entry;
if (Atomic::cmpxchg(&_head, old_head, new_head) == old_head) {
// successfully push
new_head->_next = (HeapDumpLargeObjectListElem*)old_head;
return;
}
}
}
oop pop() {
if (_head == NULL) {
return NULL;
}
HeapDumpLargeObjectListElem* entry = (HeapDumpLargeObjectListElem*)_head;
_head = _head->_next;
assert (entry != NULL, "illegal larger object list entry");
oop ret = entry->_obj;
delete entry;
assert (ret != NULL, "illegal oop pointer");
return ret;
}
void drain(ObjectClosure* cl) {
while (_head != NULL) {
cl->do_object(pop());
}
}
bool is_empty() {
return _head == NULL;
}
static const size_t LargeObjectSizeThreshold = 1 << 20; // 1 MB
};
class VM_HeapDumper;
// Support class using when iterating over the heap.
class HeapObjectDumper : public ObjectClosure {
private:
AbstractDumpWriter* _writer;
HeapDumpLargeObjectList* _list;
AbstractDumpWriter* writer() { return _writer; }
bool is_large(oop o);
public:
HeapObjectDumper(AbstractDumpWriter* writer, HeapDumpLargeObjectList* list = NULL) {
_writer = writer;
_list = list;
}
// called for each object in the heap
void do_object(oop o);
};
void HeapObjectDumper::do_object(oop o) {
// skip classes as these emitted as HPROF_GC_CLASS_DUMP records
if (o->klass() == vmClasses::Class_klass()) {
if (!java_lang_Class::is_primitive(o)) {
return;
}
}
if (DumperSupport::mask_dormant_archived_object(o) == NULL) {
log_debug(cds, heap)("skipped dormant archived object " INTPTR_FORMAT " (%s)", p2i(o), o->klass()->external_name());
return;
}
// If large object list exists and it is large object/array,
// add oop into the list and skip scan. VM thread will process it later.
if (_list != NULL && is_large(o)) {
_list->atomic_push(o);
return;
}
if (o->is_instance()) {
// create a HPROF_GC_INSTANCE record for each object
DumperSupport::dump_instance(writer(), o);
} else if (o->is_objArray()) {
// create a HPROF_GC_OBJ_ARRAY_DUMP record for each object array
DumperSupport::dump_object_array(writer(), objArrayOop(o));
} else if (o->is_typeArray()) {
// create a HPROF_GC_PRIM_ARRAY_DUMP record for each type array
DumperSupport::dump_prim_array(writer(), typeArrayOop(o));
}
}
bool HeapObjectDumper::is_large(oop o) {
size_t size = 0;
if (o->is_instance()) {
// Use o->size() * 8 as the upper limit of instance size to avoid iterating static fields
size = o->size() * 8;
} else if (o->is_objArray()) {
objArrayOop array = objArrayOop(o);
BasicType type = ArrayKlass::cast(array->klass())->element_type();
assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
int length = array->length();
int type_size = sizeof(address);
size = (size_t)length * type_size;
} else if (o->is_typeArray()) {
typeArrayOop array = typeArrayOop(o);
BasicType type = ArrayKlass::cast(array->klass())->element_type();
assert(type >= T_BOOLEAN && type <= T_OBJECT, "invalid array element type");
int length = array->length();
int type_size = type2aelembytes(type);
size = (size_t)length * type_size;
}
return size > HeapDumpLargeObjectList::LargeObjectSizeThreshold;
}
// The dumper controller for parallel heap dump
class DumperController : public CHeapObj<mtInternal> {
private:
bool _started;
Monitor* _lock;
uint _dumper_number;
uint _complete_number;
public:
DumperController(uint number) :
_started(false),
_lock(new (std::nothrow) PaddedMonitor(Mutex::safepoint, "DumperController_lock")),
_dumper_number(number),
_complete_number(0) { }
~DumperController() { delete _lock; }
void wait_for_start_signal() {
MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
while (_started == false) {
ml.wait();
}
assert(_started == true, "dumper woke up with wrong state");
}
void start_dump() {
assert (_started == false, "start dump with wrong state");
MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
_started = true;
ml.notify_all();
}
void dumper_complete() {
assert (_started == true, "dumper complete with wrong state");
MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
_complete_number++;
ml.notify();
}
void wait_all_dumpers_complete() {
assert (_started == true, "wrong state when wait for dumper complete");
MonitorLocker ml(_lock, Mutex::_no_safepoint_check_flag);
while (_complete_number != _dumper_number) {
ml.wait();
}
_started = false;
}
};
// The VM operation that performs the heap dump
class VM_HeapDumper : public VM_GC_Operation, public WorkerTask {
private:
static VM_HeapDumper* _global_dumper;
static DumpWriter* _global_writer;
DumpWriter* _local_writer;
JavaThread* _oome_thread;
Method* _oome_constructor;
bool _gc_before_heap_dump;
GrowableArray<Klass*>* _klass_map;
ThreadStackTrace** _stack_traces;
int _num_threads;
// parallel heap dump support
uint _num_dumper_threads;
uint _num_writer_threads;
DumperController* _dumper_controller;
ParallelObjectIterator* _poi;
HeapDumpLargeObjectList* _large_object_list;
// VMDumperType is for thread that dumps both heap and non-heap data.
static const size_t VMDumperType = 0;
static const size_t WriterType = 1;
static const size_t DumperType = 2;
// worker id of VMDumper thread.
static const size_t VMDumperWorkerId = 0;
size_t get_worker_type(uint worker_id) {
assert(_num_writer_threads >= 1, "Must be at least one writer");
// worker id of VMDumper that dump heap and non-heap data
if (worker_id == VMDumperWorkerId) {
return VMDumperType;
}
// worker id of dumper starts from 1, which only dump heap datar
if (worker_id < _num_dumper_threads) {
return DumperType;
}
// worker id of writer starts from _num_dumper_threads
return WriterType;
}
void prepare_parallel_dump(uint num_total) {
assert (_dumper_controller == NULL, "dumper controller must be NULL");
assert (num_total > 0, "active workers number must >= 1");
// Dumper threads number must not be larger than active workers number.
if (num_total < _num_dumper_threads) {
_num_dumper_threads = num_total - 1;
}
// Calculate dumper and writer threads number.
_num_writer_threads = num_total - _num_dumper_threads;
// If dumper threads number is 1, only the VMThread works as a dumper.
// If dumper threads number is equal to active workers, need at lest one worker thread as writer.
if (_num_dumper_threads > 0 && _num_writer_threads == 0) {
_num_writer_threads = 1;
_num_dumper_threads = num_total - _num_writer_threads;
}
// Prepare parallel writer.
if (_num_dumper_threads > 1) {
ParDumpWriter::before_work();
// Number of dumper threads that only iterate heap.
uint _heap_only_dumper_threads = _num_dumper_threads - 1 /* VMDumper thread */;
_dumper_controller = new (std::nothrow) DumperController(_heap_only_dumper_threads);
}
}
void finish_parallel_dump() {
if (_num_dumper_threads > 1) {
ParDumpWriter::after_work();
}
}
// accessors and setters
static VM_HeapDumper* dumper() { assert(_global_dumper != NULL, "Error"); return _global_dumper; }
static DumpWriter* writer() { assert(_global_writer != NULL, "Error"); return _global_writer; }
void set_global_dumper() {
assert(_global_dumper == NULL, "Error");
_global_dumper = this;
}
void set_global_writer() {
assert(_global_writer == NULL, "Error");
_global_writer = _local_writer;
}
void clear_global_dumper() { _global_dumper = NULL; }
void clear_global_writer() { _global_writer = NULL; }
bool skip_operation() const;
// writes a HPROF_LOAD_CLASS record
static void do_load_class(Klass* k);
// writes a HPROF_GC_CLASS_DUMP record for the given class
static void do_class_dump(Klass* k);
// HPROF_GC_ROOT_THREAD_OBJ records
int do_thread(JavaThread* thread, u4 thread_serial_num);
void do_threads();
void add_class_serial_number(Klass* k, int serial_num) {
_klass_map->at_put_grow(serial_num, k);
}
// HPROF_TRACE and HPROF_FRAME records
void dump_stack_traces();
// large objects
--> --------------------
--> maximum size reached
--> --------------------
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