stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8191894: Refactor weak references in JvmtiTagHashmap to use the Access API

Browse Source 
Reviewed-by: sspitsyn, coleenp
This commit is contained in:
Erik Österlund 2018-01-08 15:12:05 +01:00
parent c6bbed9592
commit 647501969f
1 changed files with 26 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

52
src/hotspot/share/prims/jvmtiTagMap.cpp
View File

@ -30,6 +30,7 @@
#include "code/codeCache.hpp"
#include "jvmtifiles/jvmtiEnv.hpp"
#include "memory/resourceArea.hpp"
#include "oops/access.inline.hpp"
#include "oops/instanceMirrorKlass.hpp"
#include "oops/objArrayKlass.hpp"
#include "oops/objArrayOop.inline.hpp"
@ -52,10 +53,6 @@
#include "runtime/vm_operations.hpp"
#include "services/serviceUtil.hpp"
#include "utilities/macros.hpp"
#if INCLUDE_ALL_GCS
#include "gc/g1/g1SATBCardTableModRefBS.hpp"
#include "gc/parallel/parallelScavengeHeap.hpp"
#endif // INCLUDE_ALL_GCS
// JvmtiTagHashmapEntry
//
@ -78,22 +75,31 @@ class JvmtiTagHashmapEntry : public CHeapObj<mtInternal> {
}
// constructor
JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
JvmtiTagHashmapEntry(oop object, jlong tag) { init(object, tag); }
public:
// accessor methods
inline oop object() const { return _object; }
inline oop* object_addr() { return &_object; }
inline jlong tag() const { return _tag; }
inline oop* object_addr() { return &_object; }
inline oop object() { return RootAccess<ON_PHANTOM_OOP_REF>::oop_load(object_addr()); }
// Peek at the object without keeping it alive. The returned object must be
// kept alive using a normal access if it leaks out of a thread transition from VM.
inline oop object_peek() {
return RootAccess<ON_PHANTOM_OOP_REF | AS_NO_KEEPALIVE>::oop_load(object_addr());
}
inline jlong tag() const { return _tag; }
inline void set_tag(jlong tag) {
assert(tag != 0, "can't be zero");
_tag = tag;
}
inline JvmtiTagHashmapEntry* next() const { return _next; }
inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
inline bool equals(oop object) {
return object == object_peek();
}
inline JvmtiTagHashmapEntry* next() const { return _next; }
inline void set_next(JvmtiTagHashmapEntry* next) { _next = next; }
};
@ -211,7 +217,7 @@ class JvmtiTagHashmap : public CHeapObj<mtInternal> {
JvmtiTagHashmapEntry* entry = _table[i];
while (entry != NULL) {
JvmtiTagHashmapEntry* next = entry->next();
oop key = entry->object();
oop key = entry->object_peek();
assert(key != NULL, "jni weak reference cleared!!");
unsigned int h = hash(key, new_size);
JvmtiTagHashmapEntry* anchor = new_table[h];
@ -304,7 +310,7 @@ class JvmtiTagHashmap : public CHeapObj<mtInternal> {
unsigned int h = hash(key);
JvmtiTagHashmapEntry* entry = _table[h];
while (entry != NULL) {
if (entry->object() == key) {
if (entry->equals(key)) {
return entry;
}
entry = entry->next();
@ -345,7 +351,7 @@ class JvmtiTagHashmap : public CHeapObj<mtInternal> {
JvmtiTagHashmapEntry* entry = _table[h];
JvmtiTagHashmapEntry* prev = NULL;
while (entry != NULL) {
if (key == entry->object()) {
if (entry->equals(key)) {
break;
}
prev = entry;
@ -1535,16 +1541,12 @@ class TagObjectCollector : public JvmtiTagHashmapEntryClosure {
void do_entry(JvmtiTagHashmapEntry* entry) {
for (int i=0; i<_tag_count; i++) {
if (_tags[i] == entry->tag()) {
// The reference in this tag map could be the only (implicitly weak)
// reference to that object. If we hand it out, we need to keep it live wrt
// SATB marking similar to other j.l.ref.Reference referents. This is
// achieved by using a phantom load in the object() accessor.
oop o = entry->object();
assert(o != NULL && Universe::heap()->is_in_reserved(o), "sanity check");
#if INCLUDE_ALL_GCS
if (UseG1GC) {
// The reference in this tag map could be the only (implicitly weak)
// reference to that object. If we hand it out, we need to keep it live wrt
// SATB marking similar to other j.l.ref.Reference referents.
G1SATBCardTableModRefBS::enqueue(o);
}
#endif
jobject ref = JNIHandles::make_local(JavaThread::current(), o);
_object_results->append(ref);
_tag_results->append((uint64_t)entry->tag());
@ -3363,10 +3365,8 @@ void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
while (entry != NULL) {
JvmtiTagHashmapEntry* next = entry->next();
oop* obj = entry->object_addr();
// has object been GC'ed
if (!is_alive->do_object_b(entry->object())) {
if (!is_alive->do_object_b(entry->object_peek())) {
// grab the tag
jlong tag = entry->tag();
guarantee(tag != 0, "checking");
@ -3384,7 +3384,7 @@ void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
++freed;
} else {
f->do_oop(entry->object_addr());
oop new_oop = entry->object();
oop new_oop = entry->object_peek();
// if the object has moved then re-hash it and move its
// entry to its new location.
@ -3418,7 +3418,7 @@ void JvmtiTagMap::do_weak_oops(BoolObjectClosure* is_alive, OopClosure* f) {
// Re-add all the entries which were kept aside
while (delayed_add != NULL) {
JvmtiTagHashmapEntry* next = delayed_add->next();
unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object(), size);
unsigned int pos = JvmtiTagHashmap::hash(delayed_add->object_peek(), size);
delayed_add->set_next(table[pos]);
table[pos] = delayed_add;
delayed_add = next;