--- old/src/share/vm/runtime/arguments.cpp 2019-09-25 13:45:42.189080700 +0800 +++ new/src/share/vm/runtime/arguments.cpp 2019-09-25 13:45:42.090077250 +0800 @@ -305,6 +305,7 @@ { "UseOldInlining", JDK_Version::jdk(9), JDK_Version::jdk(10) }, { "AutoShutdownNMT", JDK_Version::jdk(9), JDK_Version::jdk(10) }, { "CompilationRepeat", JDK_Version::jdk(8), JDK_Version::jdk(9) }, + { "SegmentedHeapDumpThreshold", JDK_Version::jdk(9), JDK_Version::jdk(10) }, #ifdef PRODUCT { "DesiredMethodLimit", JDK_Version::jdk_update(7, 2), JDK_Version::jdk(8) }, --- old/src/share/vm/runtime/globals.hpp 2019-09-25 13:45:42.777101192 +0800 +++ new/src/share/vm/runtime/globals.hpp 2019-09-25 13:45:42.677097707 +0800 @@ -923,10 +923,6 @@ "directory) of the dump file (defaults to java_pid.hprof " \ "in the working directory)") \ \ - develop(uintx, SegmentedHeapDumpThreshold, 2*G, \ - "Generate a segmented heap dump (JAVA PROFILE 1.0.2 format) " \ - "when the heap usage is larger than this") \ - \ develop(uintx, HeapDumpSegmentSize, 1*G, \ "Approximate segment size when generating a segmented heap dump") \ \ --- old/src/share/vm/services/heapDumper.cpp 2019-09-25 13:45:43.357121405 +0800 +++ new/src/share/vm/services/heapDumper.cpp 2019-09-25 13:45:43.264118164 +0800 @@ -50,8 +50,7 @@ * src/share/demo/jvmti/hprof/hprof_io.c * * - * header "JAVA PROFILE 1.0.1" or "JAVA PROFILE 1.0.2" - * (0-terminated) + * 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 @@ -382,6 +381,8 @@ size_t _size; size_t _pos; + jlong _dump_start; + char* _error; // error message when I/O fails void set_file_descriptor(int fd) { _fd = fd; } @@ -405,6 +406,10 @@ bool is_open() const { return file_descriptor() >= 0; } void flush(); + jlong dump_start() const { return _dump_start; } + void set_dump_start(jlong pos); + julong current_record_length(); + // total number of bytes written to the disk julong bytes_written() const { return _bytes_written; } @@ -446,6 +451,7 @@ _pos = 0; _error = NULL; _bytes_written = 0L; + _dump_start = (jlong)-1; _fd = os::create_binary_file(path, false); // don't replace existing file // if the open failed we record the error @@ -473,6 +479,22 @@ } } +// sets the dump starting position +void DumpWriter::set_dump_start(jlong pos) { + _dump_start = pos; +} + +julong DumpWriter::current_record_length() { + if (is_open()) { + // calculate the size of the dump record + julong dump_end = bytes_written() + bytes_unwritten(); + assert(dump_end == (size_t)current_offset(), "checking"); + julong dump_len = dump_end - dump_start() - 4; + return dump_len; + } + return 0; +} + // write directly to the file void DumpWriter::write_internal(void* s, size_t len) { if (is_open()) { @@ -641,6 +663,18 @@ static void dump_prim_array(DumpWriter* writer, typeArrayOop array); // create HPROF_FRAME record for the given method and bci static void dump_stack_frame(DumpWriter* 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(DumpWriter* writer, arrayOop array, short header_size); + + // writes a HPROF_HEAP_DUMP_SEGMENT record + static void write_dump_header(DumpWriter* writer); + + // fixes up the length of the current dump record + static void write_current_dump_record_length(DumpWriter* writer); + + // fixes up the current dump record and writes HPROF_HEAP_DUMP_END record + static void end_of_dump(DumpWriter* writer); }; // write a header of the given type @@ -1047,50 +1081,104 @@ } } +// 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(DumpWriter* 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; + + // Create a new record if the current record is non-empty and the array can't fit. + julong current_record_length = writer->current_record_length(); + if (current_record_length > 0 && + (current_record_length + header_size + length_in_bytes) > max_juint) { + write_current_dump_record_length(writer); + write_dump_header(writer); + + // We now have an empty record. + current_record_length = 0; + } + + // Calculate max bytes we can use. + uint max_bytes = max_juint - (header_size + current_record_length); + + // Array too long for the record? + // Calculate max length and return it. + 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(DumpWriter* 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); writer->write_u1(HPROF_GC_OBJ_ARRAY_DUMP); writer->write_objectID(array); writer->write_u4(STACK_TRACE_ID); - writer->write_u4((u4)array->length()); + writer->write_u4(length); + // array class ID writer->write_classID(array->klass()); // [id]* elements - for (int index=0; indexlength(); index++) { + for (int index = 0; index < length; index++) { oop o = array->obj_at(index); writer->write_objectID(o); } } -#define WRITE_ARRAY(Array, Type, Size) \ - for (int i=0; ilength(); i++) { writer->write_##Size((Size)array->Type##_at(i)); } +#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(DumpWriter* 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; + writer->write_u1(HPROF_GC_PRIM_ARRAY_DUMP); writer->write_objectID(array); writer->write_u4(STACK_TRACE_ID); - writer->write_u4((u4)array->length()); + writer->write_u4(length); writer->write_u1(type2tag(type)); // nothing to copy - if (array->length() == 0) { + if (length == 0) { return; } // If the byte ordering is big endian then we can copy most types directly - u4 length_in_bytes = (u4)array->length() * type2aelembytes(type); switch (type) { case T_INT : { if (Bytes::is_Java_byte_ordering_different()) { - WRITE_ARRAY(array, int, u4); + WRITE_ARRAY(array, int, u4, length); } else { writer->write_raw((void*)(array->int_at_addr(0)), length_in_bytes); } @@ -1102,7 +1190,7 @@ } case T_CHAR : { if (Bytes::is_Java_byte_ordering_different()) { - WRITE_ARRAY(array, char, u2); + WRITE_ARRAY(array, char, u2, length); } else { writer->write_raw((void*)(array->char_at_addr(0)), length_in_bytes); } @@ -1110,7 +1198,7 @@ } case T_SHORT : { if (Bytes::is_Java_byte_ordering_different()) { - WRITE_ARRAY(array, short, u2); + WRITE_ARRAY(array, short, u2, length); } else { writer->write_raw((void*)(array->short_at_addr(0)), length_in_bytes); } @@ -1118,7 +1206,7 @@ } case T_BOOLEAN : { if (Bytes::is_Java_byte_ordering_different()) { - WRITE_ARRAY(array, bool, u1); + WRITE_ARRAY(array, bool, u1, length); } else { writer->write_raw((void*)(array->bool_at_addr(0)), length_in_bytes); } @@ -1126,7 +1214,7 @@ } case T_LONG : { if (Bytes::is_Java_byte_ordering_different()) { - WRITE_ARRAY(array, long, u8); + WRITE_ARRAY(array, long, u8, length); } else { writer->write_raw((void*)(array->long_at_addr(0)), length_in_bytes); } @@ -1138,14 +1226,14 @@ // use IEEE 754. case T_FLOAT : { - for (int i=0; ilength(); i++) { - dump_float( writer, array->float_at(i) ); + for (int i = 0; i < length; i++) { + dump_float(writer, array->float_at(i)); } break; } case T_DOUBLE : { - for (int i=0; ilength(); i++) { - dump_double( writer, array->double_at(i) ); + for (int i = 0; i < length; i++) { + dump_double(writer, array->double_at(i)); } break; } @@ -1362,8 +1450,6 @@ JavaThread* _oome_thread; Method* _oome_constructor; bool _gc_before_heap_dump; - bool _is_segmented_dump; - jlong _dump_start; GrowableArray* _klass_map; ThreadStackTrace** _stack_traces; int _num_threads; @@ -1382,11 +1468,6 @@ void clear_global_dumper() { _global_dumper = NULL; } void clear_global_writer() { _global_writer = NULL; } - bool is_segmented_dump() const { return _is_segmented_dump; } - void set_segmented_dump() { _is_segmented_dump = true; } - jlong dump_start() const { return _dump_start; } - void set_dump_start(jlong pos); - bool skip_operation() const; // writes a HPROF_LOAD_CLASS record @@ -1411,16 +1492,6 @@ // HPROF_TRACE and HPROF_FRAME records void dump_stack_traces(); - // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record - void write_dump_header(); - - // fixes up the length of the current dump record - void write_current_dump_record_length(); - - // fixes up the current dump record )and writes HPROF_HEAP_DUMP_END - // record in the case of a segmented heap dump) - void end_of_dump(); - public: VM_HeapDumper(DumpWriter* writer, bool gc_before_heap_dump, bool oome) : VM_GC_Operation(0 /* total collections, dummy, ignored */, @@ -1429,8 +1500,6 @@ gc_before_heap_dump) { _local_writer = writer; _gc_before_heap_dump = gc_before_heap_dump; - _is_segmented_dump = false; - _dump_start = (jlong)-1; _klass_map = new (ResourceObj::C_HEAP, mtInternal) GrowableArray(INITIAL_CLASS_COUNT, true); _stack_traces = NULL; _num_threads = 0; @@ -1470,35 +1539,23 @@ return false; } -// sets the dump starting position -void VM_HeapDumper::set_dump_start(jlong pos) { - _dump_start = pos; -} - - // writes a HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT record -void VM_HeapDumper::write_dump_header() { - if (writer()->is_open()) { - if (is_segmented_dump()) { - writer()->write_u1(HPROF_HEAP_DUMP_SEGMENT); - } else { - writer()->write_u1(HPROF_HEAP_DUMP); - } - writer()->write_u4(0); // current ticks + // writes a HPROF_HEAP_DUMP_SEGMENT record +void DumperSupport::write_dump_header(DumpWriter* writer) { + if (writer->is_open()) { + writer->write_u1(HPROF_HEAP_DUMP_SEGMENT); + writer->write_u4(0); // current ticks // record the starting position for the dump (its length will be fixed up later) - set_dump_start(writer()->current_offset()); - writer()->write_u4(0); + writer->set_dump_start(writer->current_offset()); + writer->write_u4(0); } } // fixes up the length of the current dump record -void VM_HeapDumper::write_current_dump_record_length() { - if (writer()->is_open()) { - assert(dump_start() >= 0, "no dump start recorded"); - - // calculate the size of the dump record - julong dump_end = writer()->current_offset(); - julong dump_len = (dump_end - dump_start() - 4); +void DumperSupport::write_current_dump_record_length(DumpWriter* writer) { + if (writer->is_open()) { + julong dump_end = writer->bytes_written() + writer->bytes_unwritten(); + julong dump_len = writer->current_record_length(); // record length must fit in a u4 if (dump_len > max_juint) { @@ -1506,17 +1563,18 @@ } // seek to the dump start and fix-up the length - writer()->seek_to_offset(dump_start()); - writer()->write_u4((u4)dump_len); + assert(writer->dump_start() >= 0, "no dump start recorded"); + writer->seek_to_offset(writer->dump_start()); + writer->write_u4((u4)dump_len); // adjust the total size written to keep the bytes written correct. - writer()->adjust_bytes_written(-((jlong) sizeof(u4))); + writer->adjust_bytes_written(-((jlong) sizeof(u4))); // seek to dump end so we can continue - writer()->seek_to_offset(dump_end); + writer->seek_to_offset(dump_end); // no current dump record - set_dump_start((jlong)-1); + writer->set_dump_start((jlong)-1); } } @@ -1524,33 +1582,23 @@ // new segment. void VM_HeapDumper::check_segment_length() { if (writer()->is_open()) { - if (is_segmented_dump()) { - // don't use current_offset that would be too expensive on a per record basis - julong dump_end = writer()->bytes_written() + writer()->bytes_unwritten(); - assert(dump_end == (julong)writer()->current_offset(), "checking"); - julong dump_len = (dump_end - dump_start() - 4); - assert(dump_len <= max_juint, "bad dump length"); - - if (dump_len > HeapDumpSegmentSize) { - write_current_dump_record_length(); - write_dump_header(); - } + julong dump_len = writer()->current_record_length(); + + if (dump_len > 2UL*G) { + DumperSupport::write_current_dump_record_length(writer()); + DumperSupport::write_dump_header(writer()); } } } -// fixes up the current dump record )and writes HPROF_HEAP_DUMP_END -// record in the case of a segmented heap dump) -void VM_HeapDumper::end_of_dump() { - if (writer()->is_open()) { - write_current_dump_record_length(); +// fixes up the current dump record and writes HPROF_HEAP_DUMP_END record +void DumperSupport::end_of_dump(DumpWriter* writer) { + if (writer->is_open()) { + write_current_dump_record_length(writer); - // for segmented dump we write the end record - if (is_segmented_dump()) { - writer()->write_u1(HPROF_HEAP_DUMP_END); - writer()->write_u4(0); - writer()->write_u4(0); - } + writer->write_u1(HPROF_HEAP_DUMP_END); + writer->write_u4(0); + writer->write_u4(0); } } @@ -1716,16 +1764,17 @@ // [HPROF_LOAD_CLASS]* // [[HPROF_FRAME]*|HPROF_TRACE]* // [HPROF_GC_CLASS_DUMP]* -// HPROF_HEAP_DUMP +// [HPROF_HEAP_DUMP_SEGMENT]* +// HPROF_HEAP_DUMP_END // // The HPROF_TRACE records represent the stack traces where the heap dump // is generated and a "dummy trace" record which does not include // any frames. The dummy trace record is used to be referenced as the // unknown object alloc site. // -// The HPROF_HEAP_DUMP record has a length following by sub-records. To allow -// the heap dump be generated in a single pass we remember the position of -// the dump length and fix it up after all sub-records have been written. +// Each HPROF_HEAP_DUMP_SEGMENT record has a length followed by sub-records. +// To allow the heap dump be generated in a single pass we remember the position +// of the dump length and fix it up after all sub-records have been written. // To generate the sub-records we iterate over the heap, writing // HPROF_GC_INSTANCE_DUMP, HPROF_GC_OBJ_ARRAY_DUMP, and HPROF_GC_PRIM_ARRAY_DUMP // records as we go. Once that is done we write records for some of the GC @@ -1752,15 +1801,9 @@ set_global_dumper(); set_global_writer(); - // Write the file header - use 1.0.2 for large heaps, otherwise 1.0.1 + // Write the file header - we always use 1.0.2 size_t used = ch->used(); - const char* header; - if (used > (size_t)SegmentedHeapDumpThreshold) { - set_segmented_dump(); - header = "JAVA PROFILE 1.0.2"; - } else { - header = "JAVA PROFILE 1.0.1"; - } + const char* header = "JAVA PROFILE 1.0.2"; // header is few bytes long - no chance to overflow int writer()->write_raw((void*)header, (int)strlen(header)); @@ -1780,8 +1823,8 @@ // this must be called after _klass_map is built when iterating the classes above. dump_stack_traces(); - // write HPROF_HEAP_DUMP or HPROF_HEAP_DUMP_SEGMENT - write_dump_header(); + // write HPROF_HEAP_DUMP_SEGMENT + DumperSupport::write_dump_header(writer()); // Writes HPROF_GC_CLASS_DUMP records ClassLoaderDataGraph::classes_do(&do_class_dump); @@ -1789,9 +1832,9 @@ check_segment_length(); // writes HPROF_GC_INSTANCE_DUMP records. - // After each sub-record is written check_segment_length will be invoked. When - // generated a segmented heap dump this allows us to check if the current - // segment exceeds a threshold and if so, then a new segment is started. + // After each sub-record is written check_segment_length will be invoked + // to check if the current segment exceeds a threshold. If so, a new + // segment is started. // The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk // of the heap dump. HeapObjectDumper obj_dumper(this, writer()); @@ -1817,9 +1860,8 @@ StickyClassDumper class_dumper(writer()); SystemDictionary::always_strong_classes_do(&class_dumper); - // fixes up the length of the dump record. In the case of a segmented - // heap then the HPROF_HEAP_DUMP_END record is also written. - end_of_dump(); + // fixes up the length of the dump record and writes the HPROF_HEAP_DUMP_END record. + DumperSupport::end_of_dump(writer()); // Now we clear the global variables, so that a future dumper might run. clear_global_dumper();