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8186777: Make Klass::_java_mirror an OopHandle

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Add indirection for fetching mirror so that GC doesn't have to follow CLD::_klasses

Co-authored-by: Rickard Backman <rickard.backman@oracle.com>
Reviewed-by: hseigel, thartmann, eosterlund, stefank
This commit is contained in:
Coleen Phillimore 2017-10-03 16:42:04 -04:00
parent e31bc5637a
commit 73a801bc43
61 changed files with 383 additions and 477 deletions
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28
src/hotspot/share/classfile/classLoaderData.hpp
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@ -87,9 +87,9 @@ class ClassLoaderDataGraph : public AllStatic {
static void purge();
static void clear_claimed_marks();
// oops do
static void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
static void keep_alive_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
static void always_strong_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim);
static void oops_do(OopClosure* f, bool must_claim);
static void keep_alive_oops_do(OopClosure* blk, bool must_claim);
static void always_strong_oops_do(OopClosure* blk, bool must_claim);
// cld do
static void cld_do(CLDClosure* cl);
static void cld_unloading_do(CLDClosure* cl);
@ -230,10 +230,16 @@ class ClassLoaderData : public CHeapObj<mtClass> {
Mutex* _metaspace_lock; // Locks the metaspace for allocations and setup.
bool _unloading; // true if this class loader goes away
bool _is_anonymous; // if this CLD is for an anonymous class
// Remembered sets support for the oops in the class loader data.
bool _modified_oops; // Card Table Equivalent (YC/CMS support)
bool _accumulated_modified_oops; // Mod Union Equivalent (CMS support)
s2 _keep_alive; // if this CLD is kept alive without a keep_alive_object().
// Used for anonymous classes and the boot class
// loader. _keep_alive does not need to be volatile or
// atomic since there is one unique CLD per anonymous class.
volatile int _claimed; // true if claimed, for example during GC traces.
// To avoid applying oop closure more than once.
// Has to be an int because we cas it.
@ -276,6 +282,19 @@ class ClassLoaderData : public CHeapObj<mtClass> {
bool claimed() const { return _claimed == 1; }
bool claim();
// The CLD are not placed in the Heap, so the Card Table or
// the Mod Union Table can't be used to mark when CLD have modified oops.
// The CT and MUT bits saves this information for the whole class loader data.
void clear_modified_oops() { _modified_oops = false; }
public:
void record_modified_oops() { _modified_oops = true; }
bool has_modified_oops() { return _modified_oops; }
void accumulate_modified_oops() { if (has_modified_oops()) _accumulated_modified_oops = true; }
void clear_accumulated_modified_oops() { _accumulated_modified_oops = false; }
bool has_accumulated_modified_oops() { return _accumulated_modified_oops; }
private:
void unload();
bool keep_alive() const { return _keep_alive > 0; }
void classes_do(void f(Klass*));
@ -346,8 +365,7 @@ class ClassLoaderData : public CHeapObj<mtClass> {
inline unsigned int identity_hash() const { return (unsigned int)(((intptr_t)this) >> 3); }
// Used when tracing from klasses.
void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim);
void oops_do(OopClosure* f, bool must_claim, bool clear_modified_oops = false);
void classes_do(KlassClosure* klass_closure);
Klass* klasses() { return _klasses; }