これらは, 保守運用機能のためのクラス. より具体的に言うと, Java ヒープの中身を (hprof フォーマットで) ファイルにダンプするためのクラス (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.hpp))
// HeapDumper is used to dump the java heap to file in HPROF binary format:
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
/*
* HPROF binary format - description copied from:
* src/share/demo/jvmti/hprof/hprof_io.c
*
*
* header "JAVA PROFILE 1.0.1" or "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. For example, on
* Solaris and Win32, the size is 4.
* 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
*
*/
保守運用機能のためのクラス (関連する serviceability 機能からのみ使用される).
Java ヒープの中身を (hprof フォーマットで) ファイルにダンプするための一時オブジェクト(StackObjクラス) (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.hpp))
class HeapDumper : public StackObj {
HeapDumper 型の局所変数を作り, HeapDumper::dump() メソッドを呼び出すだけ.
((cite: hotspot/src/share/vm/services/heapDumper.hpp))
// { HeapDumper dumper(true /* full GC before heap dump */);
// if (dumper.dump("/export/java.hprof")) {
// ResourceMark rm;
// tty->print_cr("Dump failed: %s", dumper.error_as_C_string());
// } else {
// // dump succeeded
// }
// }
あるいは, インスタンスを作らずに HeapDumper::dump_heap() を直接呼ぶという手もある模様 (この場合は内部でインスタンスが作られた後 dump() が呼び出される).
以下の箇所で(のみ)使用されている.
Platform MXBean である sun.management.HotSpotDiagnostic クラス用の補助関数. sun.management.HotSpotDiagnostic.dumpHeap() から(のみ)呼び出される.
保守運用機能用の関数. GC 実行前に呼び出され, 関連するコマンドラインオプションの値に応じてヒープの情報を出力する. HeapDumpBeforeFullGC オプションが指定されていると, HeapDumper が呼び出される.
保守運用機能用の関数. GC 実行後に呼び出され, 関連するコマンドラインオプションの値に応じてヒープの情報を出力する. HeapDumpAfterFullGC オプションが指定されていると, HeapDumper が呼び出される.
Attach API の "dumpheap" コマンドの処理を行う関数.
See: here for details
HeapDumper クラス内で使用される補助クラス.
ダンプの出力先ファイルを管理する (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Supports I/O operations on a dump file
class DumpWriter : public StackObj {
See: here for details
HeapDumper クラス内で使用される補助クラス.
ダンプ用のユーティリティ関数を納めた名前空間(AllStatic クラス) (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class with a collection of functions used when dumping the heap
class DumperSupport : AllStatic {
See: here for details
HeapDumper クラス内で使用される補助クラス.
SymbolTable 内の情報を元に HPROF_UTF8 record を出力する (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class used to generate HPROF_UTF8 records from the entries in the
// SymbolTable.
class SymbolTableDumper : public SymbolClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
HPROF_GC_ROOT_JNI_LOCAL レコードの出力を行う (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class used to generate HPROF_GC_ROOT_JNI_LOCAL records
class JNILocalsDumper : public OopClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
HPROF_GC_ROOT_JNI_GLOBAL レコードの出力を行う (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class used to generate HPROF_GC_ROOT_JNI_GLOBAL records
class JNIGlobalsDumper : public OopClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
HPROF_GC_ROOT_MONITOR_USED レコードの出力を行う (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class used to generate HPROF_GC_ROOT_MONITOR_USED records
class MonitorUsedDumper : public OopClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
HPROF_GC_ROOT_STICKY_CLASS レコードの出力を行う (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class used to generate HPROF_GC_ROOT_STICKY_CLASS records
class StickyClassDumper : public OopClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
HPROF_GC_INSTANCE_DUMP レコードや HPROF_GC_OBJ_ARRAY_DUMPレコード, HPROF_GC_PRIM_ARRAY_DUMP レコードの出力を行う (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// Support class using when iterating over the heap.
class HeapObjectDumper : public ObjectClosure {
See: here for details
HeapDumper クラス内で使用される補助クラス.
スレッドを停止させた状態でダンプ処理を行うための VM_GC_Operation クラス. 実際のダンプ処理はこのクラス内で行われる (See: here for details).
((cite: hotspot/src/share/vm/services/heapDumper.cpp))
// The VM operation that performs the heap dump
class VM_HeapDumper : public VM_GC_Operation {
See: here for details
This document is available under the GNU GENERAL PUBLIC LICENSE Version 2.