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src/hotspot/share/prims/jvmtiTagMap.cpp
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@@ -26,10 +26,11 @@
#include "classfile/classLoaderDataGraph.hpp"
#include "classfile/javaClasses.inline.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/systemDictionary.hpp"
#include "classfile/vmSymbols.hpp"
+#include "gc/shared/collectedHeap.hpp"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "logging/log.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
@@ -44,11 +45,10 @@
#include "prims/jvmtiEventController.hpp"
#include "prims/jvmtiEventController.inline.hpp"
#include "prims/jvmtiExport.hpp"
#include "prims/jvmtiImpl.hpp"
#include "prims/jvmtiTagMap.hpp"
-#include "runtime/biasedLocking.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/jniHandles.inline.hpp"
#include "runtime/mutex.hpp"
@@ -1610,141 +1610,25 @@
entry_iterate(&collector);
}
return collector.result(count_ptr, object_result_ptr, tag_result_ptr);
}
-
-// ObjectMarker is used to support the marking objects when walking the
-// heap.
-//
-// This implementation uses the existing mark bits in an object for
-// marking. Objects that are marked must later have their headers restored.
-// As most objects are unlocked and don't have their identity hash computed
-// we don't have to save their headers. Instead we save the headers that
-// are "interesting". Later when the headers are restored this implementation
-// restores all headers to their initial value and then restores the few
-// objects that had interesting headers.
-//
-// Future work: This implementation currently uses growable arrays to save
-// the oop and header of interesting objects. As an optimization we could
-// use the same technique as the GC and make use of the unused area
-// between top() and end().
-//
-
-// An ObjectClosure used to restore the mark bits of an object
-class RestoreMarksClosure : public ObjectClosure {
- public:
- void do_object(oop o) {
- if (o != NULL) {
- markWord mark = o->mark();
- if (mark.is_marked()) {
- o->init_mark();
- }
- }
- }
-};
-
-// ObjectMarker provides the mark and visited functions
-class ObjectMarker : AllStatic {
- private:
- // saved headers
- static GrowableArray<oop>* _saved_oop_stack;
- static GrowableArray<markWord>* _saved_mark_stack;
- static bool _needs_reset; // do we need to reset mark bits?
-
- public:
- static void init(); // initialize
- static void done(); // clean-up
-
- static inline void mark(oop o); // mark an object
- static inline bool visited(oop o); // check if object has been visited
-
- static inline bool needs_reset() { return _needs_reset; }
- static inline void set_needs_reset(bool v) { _needs_reset = v; }
-};
-
-GrowableArray<oop>* ObjectMarker::_saved_oop_stack = NULL;
-GrowableArray<markWord>* ObjectMarker::_saved_mark_stack = NULL;
-bool ObjectMarker::_needs_reset = true; // need to reset mark bits by default
-
-// initialize ObjectMarker - prepares for object marking
-void ObjectMarker::init() {
- assert(Thread::current()->is_VM_thread(), "must be VMThread");
-
- // prepare heap for iteration
- Universe::heap()->ensure_parsability(false); // no need to retire TLABs
-
- // create stacks for interesting headers
- _saved_mark_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<markWord>(4000, true);
- _saved_oop_stack = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<oop>(4000, true);
-
- if (UseBiasedLocking) {
- BiasedLocking::preserve_marks();
- }
-}
-
-// Object marking is done so restore object headers
-void ObjectMarker::done() {
- // iterate over all objects and restore the mark bits to
- // their initial value
- RestoreMarksClosure blk;
- if (needs_reset()) {
- Universe::heap()->object_iterate(&blk);
- } else {
- // We don't need to reset mark bits on this call, but reset the
- // flag to the default for the next call.
- set_needs_reset(true);
- }
-
- // now restore the interesting headers
- for (int i = 0; i < _saved_oop_stack->length(); i++) {
- oop o = _saved_oop_stack->at(i);
- markWord mark = _saved_mark_stack->at(i);
- o->set_mark(mark);
- }
-
- if (UseBiasedLocking) {
- BiasedLocking::restore_marks();
- }
-
- // free the stacks
- delete _saved_oop_stack;
- delete _saved_mark_stack;
-}
-
-// mark an object
-inline void ObjectMarker::mark(oop o) {
- assert(Universe::heap()->is_in(o), "sanity check");
- assert(!o->mark().is_marked(), "should only mark an object once");
-
- // object's mark word
- markWord mark = o->mark();
-
- if (o->mark_must_be_preserved(mark)) {
- _saved_mark_stack->push(mark);
- _saved_oop_stack->push(o);
- }
-
- // mark the object
- o->set_mark(markWord::prototype().set_marked());
-}
-
-// return true if object is marked
-inline bool ObjectMarker::visited(oop o) {
- return o->mark().is_marked();
-}
-
// Stack allocated class to help ensure that ObjectMarker is used
// correctly. Constructor initializes ObjectMarker, destructor calls
// ObjectMarker's done() function to restore object headers.
class ObjectMarkerController : public StackObj {
- public:
- ObjectMarkerController() {
- ObjectMarker::init();
- }
- ~ObjectMarkerController() {
- ObjectMarker::done();
+private:
+ ObjectMarker* _marker;
+
+public:
+ ObjectMarkerController();
+ ~ObjectMarkerController();
+
+ bool init();
+
+ inline ObjectMarker* object_marker() const {
+ return _marker;
}
};
// helper to map a jvmtiHeapReferenceKind to an old style jvmtiHeapRootKind
@@ -1853,10 +1737,12 @@
// into to invoke callbacks. It works in one of two modes. The "basic" mode is
// used for the deprecated IterateOverReachableObjects functions. The "advanced"
// mode is for the newer FollowReferences function which supports a lot of
// additional callbacks.
class CallbackInvoker : AllStatic {
+ friend class ObjectMarkerController;
+
private:
// heap walk styles
enum { basic, advanced };
static int _heap_walk_type;
static bool is_basic_heap_walk() { return _heap_walk_type == basic; }
@@ -1878,20 +1764,21 @@
// context needed for all heap walks
static JvmtiTagMap* _tag_map;
static const void* _user_data;
static GrowableArray<oop>* _visit_stack;
+ static ObjectMarker* _object_marker;
// accessors
static JvmtiTagMap* tag_map() { return _tag_map; }
static const void* user_data() { return _user_data; }
static GrowableArray<oop>* visit_stack() { return _visit_stack; }
// if the object hasn't been visited then push it onto the visit stack
// so that it will be visited later
static inline bool check_for_visit(oop obj) {
- if (!ObjectMarker::visited(obj)) visit_stack()->push(obj);
+ if (!_object_marker->marked(obj)) visit_stack()->push(obj);
return true;
}
// invoke basic style callbacks
static inline bool invoke_basic_heap_root_callback
@@ -1957,10 +1844,11 @@
BasicHeapWalkContext CallbackInvoker::_basic_context;
AdvancedHeapWalkContext CallbackInvoker::_advanced_context;
JvmtiTagMap* CallbackInvoker::_tag_map;
const void* CallbackInvoker::_user_data;
GrowableArray<oop>* CallbackInvoker::_visit_stack;
+ObjectMarker* CallbackInvoker::_object_marker;
// initialize for basic heap walk (IterateOverReachableObjects et al)
void CallbackInvoker::initialize_for_basic_heap_walk(JvmtiTagMap* tag_map,
GrowableArray<oop>* visit_stack,
const void* user_data,
@@ -2547,10 +2435,29 @@
} else {
return invoke_advanced_object_reference_callback(JVMTI_HEAP_REFERENCE_CONSTANT_POOL, referrer, referree, index);
}
}
+
+ObjectMarkerController::ObjectMarkerController() {
+ _marker = Universe::heap()->object_marker();
+}
+
+bool ObjectMarkerController::init() {
+ if (_marker->init()) {
+ CallbackInvoker::_object_marker = _marker;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+ObjectMarkerController::~ObjectMarkerController() {
+ CallbackInvoker::_object_marker = NULL;
+ _marker->done();
+}
+
// A supporting closure used to process simple roots
class SimpleRootsClosure : public OopClosure {
private:
jvmtiHeapReferenceKind _kind;
bool _continue;
@@ -3190,14 +3097,10 @@
// first mark the object as visited
// second get all the outbound references from this object (in other words, all
// the objects referenced by this object).
//
bool VM_HeapWalkOperation::visit(oop o) {
- // mark object as visited
- assert(!ObjectMarker::visited(o), "can't visit same object more than once");
- ObjectMarker::mark(o);
-
// instance
if (o->is_instance()) {
if (o->klass() == SystemDictionary::Class_klass()) {
if (!java_lang_Class::is_primitive(o)) {
// a java.lang.Class
@@ -3222,30 +3125,34 @@
}
void VM_HeapWalkOperation::doit() {
ResourceMark rm;
ObjectMarkerController marker;
- ClassFieldMapCacheMark cm;
+ if (!marker.init()) {
+ return;
+ }
+ ClassFieldMapCacheMark cm;
assert(visit_stack()->is_empty(), "visit stack must be empty");
+ ObjectMarker* const object_marker = marker.object_marker();
// the heap walk starts with an initial object or the heap roots
if (initial_object().is_null()) {
// If either collect_stack_roots() or collect_simple_roots()
// returns false at this point, then there are no mark bits
// to reset.
- ObjectMarker::set_needs_reset(false);
+ object_marker->set_needs_reset(false);
// Calling collect_stack_roots() before collect_simple_roots()
// can result in a big performance boost for an agent that is
// focused on analyzing references in the thread stacks.
if (!collect_stack_roots()) return;
if (!collect_simple_roots()) return;
// no early return so enable heap traversal to reset the mark bits
- ObjectMarker::set_needs_reset(true);
+ object_marker->set_needs_reset(true);
} else {
visit_stack()->push(initial_object()());
}
// object references required
@@ -3253,11 +3160,11 @@
// visit each object until all reachable objects have been
// visited or the callback asked to terminate the iteration.
while (!visit_stack()->is_empty()) {
oop o = visit_stack()->pop();
- if (!ObjectMarker::visited(o)) {
+ if (object_marker->mark(o)) {
if (!visit(o)) {
break;
}
}
}
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