--- a/hotspot/src/share/vm/classfile/classFileParser.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/classfile/classFileParser.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -232,7 +232,9 @@
length >= 1, "Illegal constant pool size %u in class file %s",
length, CHECK_(nullHandle));
constantPoolOop constant_pool =
- oopFactory::new_constantPool(length, CHECK_(nullHandle));
+ oopFactory::new_constantPool(length,
+ methodOopDesc::IsSafeConc,
+ CHECK_(nullHandle));
constantPoolHandle cp (THREAD, constant_pool);
cp->set_partially_loaded(); // Enables heap verify to work on partial constantPoolOops
@@ -1675,7 +1677,8 @@
// All sizing information for a methodOop is finally available, now create it
methodOop m_oop = oopFactory::new_method(
code_length, access_flags, linenumber_table_length,
- total_lvt_length, checked_exceptions_length, CHECK_(nullHandle));
+ total_lvt_length, checked_exceptions_length,
+ methodOopDesc::IsSafeConc, CHECK_(nullHandle));
methodHandle m (THREAD, m_oop);
ClassLoadingService::add_class_method_size(m_oop->size()*HeapWordSize);
--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -706,6 +706,30 @@
}
}
+// Apply the given closure to each live object in the space
+// The usage of CompactibleFreeListSpace
+// by the ConcurrentMarkSweepGeneration for concurrent GC's allows
+// objects in the space with references to objects that are no longer
+// valid. For example, an object may reference another object
+// that has already been sweep up (collected). This method uses
+// obj_is_alive() to determine whether it is safe to apply the closure to
+// an object. See obj_is_alive() for details on how liveness of an
+// object is decided.
+
+void CompactibleFreeListSpace::safe_object_iterate(ObjectClosure* blk) {
+ assert_lock_strong(freelistLock());
+ NOT_PRODUCT(verify_objects_initialized());
+ HeapWord *cur, *limit;
+ size_t curSize;
+ for (cur = bottom(), limit = end(); cur < limit;
+ cur += curSize) {
+ curSize = block_size(cur);
+ if (block_is_obj(cur) && obj_is_alive(cur)) {
+ blk->do_object(oop(cur));
+ }
+ }
+}
+
void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr,
UpwardsObjectClosure* cl) {
assert_locked();
@@ -861,7 +885,9 @@
} else {
// must read from what 'p' points to in each loop.
klassOop k = ((volatile oopDesc*)p)->klass_or_null();
- if (k != NULL && ((oopDesc*)p)->is_parsable()) {
+ if (k != NULL &&
+ ((oopDesc*)p)->is_parsable() &&
+ ((oopDesc*)p)->is_conc_safe()) {
assert(k->is_oop(), "Should really be klass oop.");
oop o = (oop)p;
assert(o->is_oop(), "Should be an oop");
--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -481,6 +481,15 @@
void oop_iterate(OopClosure* cl);
void object_iterate(ObjectClosure* blk);
+ // Apply the closure to each object in the space whose references
+ // point to objects in the heap. The usage of CompactibleFreeListSpace
+ // by the ConcurrentMarkSweepGeneration for concurrent GC's allows
+ // objects in the space with references to objects that are no longer
+ // valid. For example, an object may reference another object
+ // that has already been sweep up (collected). This method uses
+ // obj_is_alive() to determine whether it is safe to iterate of
+ // an object.
+ void safe_object_iterate(ObjectClosure* blk);
void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
// Requires that "mr" be entirely within the space.
--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -3018,6 +3018,16 @@
}
void
+ConcurrentMarkSweepGeneration::safe_object_iterate(ObjectClosure* cl) {
+ if (freelistLock()->owned_by_self()) {
+ Generation::safe_object_iterate(cl);
+ } else {
+ MutexLockerEx x(freelistLock(), Mutex::_no_safepoint_check_flag);
+ Generation::safe_object_iterate(cl);
+ }
+}
+
+void
ConcurrentMarkSweepGeneration::pre_adjust_pointers() {
}
@@ -6623,7 +6633,11 @@
if (_bitMap->isMarked(addr)) {
// it's marked; is it potentially uninitialized?
if (p->klass_or_null() != NULL) {
- if (CMSPermGenPrecleaningEnabled && !p->is_parsable()) {
+ // If is_conc_safe is false, the object may be undergoing
+ // change by the VM outside a safepoint. Don't try to
+ // scan it, but rather leave it for the remark phase.
+ if (CMSPermGenPrecleaningEnabled &&
+ (!p->is_conc_safe() || !p->is_parsable())) {
// Signal precleaning to redirty the card since
// the klass pointer is already installed.
assert(size == 0, "Initial value");
@@ -7001,7 +7015,6 @@
_mut->clear_range(mr);
}
DEBUG_ONLY(})
-
// Note: the finger doesn't advance while we drain
// the stack below.
PushOrMarkClosure pushOrMarkClosure(_collector,
@@ -8062,9 +8075,13 @@
#ifdef DEBUG
if (oop(addr)->klass_or_null() != NULL &&
( !_collector->should_unload_classes()
- || oop(addr)->is_parsable())) {
+ || (oop(addr)->is_parsable()) &&
+ oop(addr)->is_conc_safe())) {
// Ignore mark word because we are running concurrent with mutators
assert(oop(addr)->is_oop(true), "live block should be an oop");
+ // is_conc_safe is checked before performing this assertion
+ // because an object that is not is_conc_safe may yet have
+ // the return from size() correct.
assert(size ==
CompactibleFreeListSpace::adjustObjectSize(oop(addr)->size()),
"P-mark and computed size do not agree");
@@ -8077,6 +8094,13 @@
(!_collector->should_unload_classes()
|| oop(addr)->is_parsable()),
"Should be an initialized object");
+ // Note that there are objects used during class redefinition
+ // (e.g., merge_cp in VM_RedefineClasses::merge_cp_and_rewrite()
+ // which are discarded with their is_conc_safe state still
+ // false. These object may be floating garbage so may be
+ // seen here. If they are floating garbage their size
+ // should be attainable from their klass. Do not that
+ // is_conc_safe() is true for oop(addr).
// Ignore mark word because we are running concurrent with mutators
assert(oop(addr)->is_oop(true), "live block should be an oop");
// Verify that the bit map has no bits marked between
--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -1212,6 +1212,7 @@
// More iteration support
virtual void oop_iterate(MemRegion mr, OopClosure* cl);
virtual void oop_iterate(OopClosure* cl);
+ virtual void safe_object_iterate(ObjectClosure* cl);
virtual void object_iterate(ObjectClosure* cl);
// Need to declare the full complement of closures, whether we'll
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -1285,7 +1285,9 @@
_unclean_regions_coming(false),
_young_list(new YoungList(this)),
_gc_time_stamp(0),
- _surviving_young_words(NULL)
+ _surviving_young_words(NULL),
+ _in_cset_fast_test(NULL),
+ _in_cset_fast_test_base(NULL)
{
_g1h = this; // To catch bugs.
if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
@@ -2485,6 +2487,19 @@
g1_policy()->record_collection_pause_start(start_time_sec,
start_used_bytes);
+ guarantee(_in_cset_fast_test == NULL, "invariant");
+ guarantee(_in_cset_fast_test_base == NULL, "invariant");
+ _in_cset_fast_test_length = n_regions();
+ _in_cset_fast_test_base =
+ NEW_C_HEAP_ARRAY(bool, _in_cset_fast_test_length);
+ memset(_in_cset_fast_test_base, false,
+ _in_cset_fast_test_length * sizeof(bool));
+ // We're biasing _in_cset_fast_test to avoid subtracting the
+ // beginning of the heap every time we want to index; basically
+ // it's the same with what we do with the card table.
+ _in_cset_fast_test = _in_cset_fast_test_base -
+ ((size_t) _g1_reserved.start() >> HeapRegion::LogOfHRGrainBytes);
+
#if SCAN_ONLY_VERBOSE
_young_list->print();
#endif // SCAN_ONLY_VERBOSE
@@ -2553,6 +2568,12 @@
free_collection_set(g1_policy()->collection_set());
g1_policy()->clear_collection_set();
+ FREE_C_HEAP_ARRAY(bool, _in_cset_fast_test_base);
+ // this is more for peace of mind; we're nulling them here and
+ // we're expecting them to be null at the beginning of the next GC
+ _in_cset_fast_test = NULL;
+ _in_cset_fast_test_base = NULL;
+
if (popular_region != NULL) {
// We have to wait until now, because we don't want the region to
// be rescheduled for pop-evac during RS update.
@@ -3560,6 +3581,9 @@
size_t undo_waste() { return _undo_waste; }
void push_on_queue(oop* ref) {
+ assert(ref != NULL, "invariant");
+ assert(has_partial_array_mask(ref) || _g1h->obj_in_cs(*ref), "invariant");
+
if (!refs()->push(ref)) {
overflowed_refs()->push(ref);
IF_G1_DETAILED_STATS(note_overflow_push());
@@ -3572,6 +3596,10 @@
if (!refs()->pop_local(ref)) {
ref = NULL;
} else {
+ assert(ref != NULL, "invariant");
+ assert(has_partial_array_mask(ref) || _g1h->obj_in_cs(*ref),
+ "invariant");
+
IF_G1_DETAILED_STATS(note_pop());
}
}
@@ -3601,8 +3629,7 @@
obj = alloc_buf->allocate(word_sz);
assert(obj != NULL, "buffer was definitely big enough...");
- }
- else {
+ } else {
obj = _g1h->par_allocate_during_gc(purpose, word_sz);
}
return obj;
@@ -3695,24 +3722,57 @@
}
}
+private:
+ void deal_with_reference(oop* ref_to_scan) {
+ if (has_partial_array_mask(ref_to_scan)) {
+ _partial_scan_cl->do_oop_nv(ref_to_scan);
+ } else {
+ // Note: we can use "raw" versions of "region_containing" because
+ // "obj_to_scan" is definitely in the heap, and is not in a
+ // humongous region.
+ HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
+ _evac_cl->set_region(r);
+ _evac_cl->do_oop_nv(ref_to_scan);
+ }
+ }
+
+public:
void trim_queue() {
+ // I've replicated the loop twice, first to drain the overflow
+ // queue, second to drain the task queue. This is better than
+ // having a single loop, which checks both conditions and, inside
+ // it, either pops the overflow queue or the task queue, as each
+ // loop is tighter. Also, the decision to drain the overflow queue
+ // first is not arbitrary, as the overflow queue is not visible
+ // to the other workers, whereas the task queue is. So, we want to
+ // drain the "invisible" entries first, while allowing the other
+ // workers to potentially steal the "visible" entries.
+
while (refs_to_scan() > 0 || overflowed_refs_to_scan() > 0) {
- oop *ref_to_scan = NULL;
- if (overflowed_refs_to_scan() == 0) {
- pop_from_queue(ref_to_scan);
- } else {
+ while (overflowed_refs_to_scan() > 0) {
+ oop *ref_to_scan = NULL;
pop_from_overflow_queue(ref_to_scan);
+ assert(ref_to_scan != NULL, "invariant");
+ // We shouldn't have pushed it on the queue if it was not
+ // pointing into the CSet.
+ assert(ref_to_scan != NULL, "sanity");
+ assert(has_partial_array_mask(ref_to_scan) ||
+ _g1h->obj_in_cs(*ref_to_scan), "sanity");
+
+ deal_with_reference(ref_to_scan);
}
- if (ref_to_scan != NULL) {
- if ((intptr_t)ref_to_scan & G1_PARTIAL_ARRAY_MASK) {
- _partial_scan_cl->do_oop_nv(ref_to_scan);
- } else {
- // Note: we can use "raw" versions of "region_containing" because
- // "obj_to_scan" is definitely in the heap, and is not in a
- // humongous region.
- HeapRegion* r = _g1h->heap_region_containing_raw(ref_to_scan);
- _evac_cl->set_region(r);
- _evac_cl->do_oop_nv(ref_to_scan);
+
+ while (refs_to_scan() > 0) {
+ oop *ref_to_scan = NULL;
+ pop_from_queue(ref_to_scan);
+
+ if (ref_to_scan != NULL) {
+ // We shouldn't have pushed it on the queue if it was not
+ // pointing into the CSet.
+ assert(has_partial_array_mask(ref_to_scan) ||
+ _g1h->obj_in_cs(*ref_to_scan), "sanity");
+
+ deal_with_reference(ref_to_scan);
}
}
}
@@ -3728,16 +3788,25 @@
// Should probably be made inline and moved in g1OopClosures.inline.hpp.
void G1ParScanClosure::do_oop_nv(oop* p) {
oop obj = *p;
+
if (obj != NULL) {
- if (_g1->obj_in_cs(obj)) {
- if (obj->is_forwarded()) {
- *p = obj->forwardee();
- } else {
- _par_scan_state->push_on_queue(p);
- return;
- }
+ if (_g1->in_cset_fast_test(obj)) {
+ // We're not going to even bother checking whether the object is
+ // already forwarded or not, as this usually causes an immediate
+ // stall. We'll try to prefetch the object (for write, given that
+ // we might need to install the forwarding reference) and we'll
+ // get back to it when pop it from the queue
+ Prefetch::write(obj->mark_addr(), 0);
+ Prefetch::read(obj->mark_addr(), (HeapWordSize*2));
+
+ // slightly paranoid test; I'm trying to catch potential
+ // problems before we go into push_on_queue to know where the
+ // problem is coming from
+ assert(obj == *p, "the value of *p should not have changed");
+ _par_scan_state->push_on_queue(p);
+ } else {
+ _g1_rem->par_write_ref(_from, p, _par_scan_state->queue_num());
}
- _g1_rem->par_write_ref(_from, p, _par_scan_state->queue_num());
}
}
@@ -3777,13 +3846,36 @@
return _g1->handle_evacuation_failure_par(cl, old);
}
+ // We're going to allocate linearly, so might as well prefetch ahead.
+ Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);
+
oop forward_ptr = old->forward_to_atomic(obj);
if (forward_ptr == NULL) {
Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz);
+ if (g1p->track_object_age(alloc_purpose)) {
+ // We could simply do obj->incr_age(). However, this causes a
+ // performance issue. obj->incr_age() will first check whether
+ // the object has a displaced mark by checking its mark word;
+ // getting the mark word from the new location of the object
+ // stalls. So, given that we already have the mark word and we
+ // are about to install it anyway, it's better to increase the
+ // age on the mark word, when the object does not have a
+ // displaced mark word. We're not expecting many objects to have
+ // a displaced marked word, so that case is not optimized
+ // further (it could be...) and we simply call obj->incr_age().
+
+ if (m->has_displaced_mark_helper()) {
+ // in this case, we have to install the mark word first,
+ // otherwise obj looks to be forwarded (the old mark word,
+ // which contains the forward pointer, was copied)
+ obj->set_mark(m);
+ obj->incr_age();
+ } else {
+ m = m->incr_age();
+ }
+ }
obj->set_mark(m);
- if (g1p->track_object_age(alloc_purpose)) {
- obj->incr_age();
- }
+
// preserve "next" mark bit
if (_g1->mark_in_progress() && !_g1->is_obj_ill(old)) {
if (!use_local_bitmaps ||
@@ -3805,9 +3897,11 @@
if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) {
arrayOop(old)->set_length(0);
- _par_scan_state->push_on_queue((oop*) ((intptr_t)old | G1_PARTIAL_ARRAY_MASK));
+ _par_scan_state->push_on_queue(set_partial_array_mask(old));
} else {
- _scanner->set_region(_g1->heap_region_containing(obj));
+ // No point in using the slower heap_region_containing() method,
+ // given that we know obj is in the heap.
+ _scanner->set_region(_g1->heap_region_containing_raw(obj));
obj->oop_iterate_backwards(_scanner);
}
} else {
@@ -3817,47 +3911,55 @@
return obj;
}
-template<bool do_gen_barrier, G1Barrier barrier, bool do_mark_forwardee>
-void G1ParCopyClosure<do_gen_barrier, barrier, do_mark_forwardee>::do_oop_work(oop* p) {
+template<bool do_gen_barrier, G1Barrier barrier,
+ bool do_mark_forwardee, bool skip_cset_test>
+void G1ParCopyClosure<do_gen_barrier, barrier,
+ do_mark_forwardee, skip_cset_test>::do_oop_work(oop* p) {
oop obj = *p;
assert(barrier != G1BarrierRS || obj != NULL,
"Precondition: G1BarrierRS implies obj is nonNull");
- if (obj != NULL) {
- if (_g1->obj_in_cs(obj)) {
+ // The only time we skip the cset test is when we're scanning
+ // references popped from the queue. And we only push on the queue
+ // references that we know point into the cset, so no point in
+ // checking again. But we'll leave an assert here for peace of mind.
+ assert(!skip_cset_test || _g1->obj_in_cs(obj), "invariant");
+
+ // here the null check is implicit in the cset_fast_test() test
+ if (skip_cset_test || _g1->in_cset_fast_test(obj)) {
#if G1_REM_SET_LOGGING
- gclog_or_tty->print_cr("Loc "PTR_FORMAT" contains pointer "PTR_FORMAT" into CS.",
- p, (void*) obj);
+ gclog_or_tty->print_cr("Loc "PTR_FORMAT" contains pointer "PTR_FORMAT" "
+ "into CS.", p, (void*) obj);
#endif
- if (obj->is_forwarded()) {
- *p = obj->forwardee();
- } else {
- *p = copy_to_survivor_space(obj);
- }
- // When scanning the RS, we only care about objs in CS.
- if (barrier == G1BarrierRS) {
- _g1_rem->par_write_ref(_from, p, _par_scan_state->queue_num());
- }
+ if (obj->is_forwarded()) {
+ *p = obj->forwardee();
+ } else {
+ *p = copy_to_survivor_space(obj);
}
- // When scanning moved objs, must look at all oops.
- if (barrier == G1BarrierEvac) {
+ // When scanning the RS, we only care about objs in CS.
+ if (barrier == G1BarrierRS) {
_g1_rem->par_write_ref(_from, p, _par_scan_state->queue_num());
}
-
- if (do_gen_barrier) {
- par_do_barrier(p);
- }
- }
-}
-
-template void G1ParCopyClosure<false, G1BarrierEvac, false>::do_oop_work(oop* p);
-
-template <class T> void G1ParScanPartialArrayClosure::process_array_chunk(
+ }
+
+ // When scanning moved objs, must look at all oops.
+ if (barrier == G1BarrierEvac && obj != NULL) {
+ _g1_rem->par_write_ref(_from, p, _par_scan_state->queue_num());
+ }
+
+ if (do_gen_barrier && obj != NULL) {
+ par_do_barrier(p);
+ }
+}
+
+template void G1ParCopyClosure<false, G1BarrierEvac, false, true>::do_oop_work(oop* p);
+
+template<class T> void G1ParScanPartialArrayClosure::process_array_chunk(
oop obj, int start, int end) {
// process our set of indices (include header in first chunk)
assert(start < end, "invariant");
T* const base = (T*)objArrayOop(obj)->base();
- T* const start_addr = base + start;
+ T* const start_addr = (start == 0) ? (T*) obj : base + start;
T* const end_addr = base + end;
MemRegion mr((HeapWord*)start_addr, (HeapWord*)end_addr);
_scanner.set_region(_g1->heap_region_containing(obj));
@@ -3866,7 +3968,8 @@
void G1ParScanPartialArrayClosure::do_oop_nv(oop* p) {
assert(!UseCompressedOops, "Needs to be fixed to work with compressed oops");
- oop old = oop((intptr_t)p & ~G1_PARTIAL_ARRAY_MASK);
+ assert(has_partial_array_mask(p), "invariant");
+ oop old = clear_partial_array_mask(p);
assert(old->is_objArray(), "must be obj array");
assert(old->is_forwarded(), "must be forwarded");
assert(Universe::heap()->is_in_reserved(old), "must be in heap.");
@@ -3884,7 +3987,7 @@
end = start + ParGCArrayScanChunk;
arrayOop(old)->set_length(end);
// Push remainder.
- _par_scan_state->push_on_queue((oop*) ((intptr_t) old | G1_PARTIAL_ARRAY_MASK));
+ _par_scan_state->push_on_queue(set_partial_array_mask(old));
} else {
// Restore length so that the heap remains parsable in
// case of evacuation failure.
@@ -3893,11 +3996,6 @@
// process our set of indices (include header in first chunk)
process_array_chunk<oop>(obj, start, end);
- oop* start_addr = start == 0 ? (oop*)obj : obj->obj_at_addr<oop>(start);
- oop* end_addr = (oop*)(obj->base()) + end; // obj_at_addr(end) asserts end < length
- MemRegion mr((HeapWord*)start_addr, (HeapWord*)end_addr);
- _scanner.set_region(_g1->heap_region_containing(obj));
- obj->oop_iterate(&_scanner, mr);
}
int G1ScanAndBalanceClosure::_nq = 0;
@@ -3931,6 +4029,13 @@
pss->hash_seed(),
ref_to_scan)) {
IF_G1_DETAILED_STATS(pss->note_steal());
+
+ // slightly paranoid tests; I'm trying to catch potential
+ // problems before we go into push_on_queue to know where the
+ // problem is coming from
+ assert(ref_to_scan != NULL, "invariant");
+ assert(has_partial_array_mask(ref_to_scan) ||
+ _g1h->obj_in_cs(*ref_to_scan), "invariant");
pss->push_on_queue(ref_to_scan);
continue;
}
@@ -3976,10 +4081,10 @@
ResourceMark rm;
HandleMark hm;
- G1ParScanThreadState pss(_g1h, i);
- G1ParScanHeapEvacClosure scan_evac_cl(_g1h, &pss);
- G1ParScanHeapEvacClosure evac_failure_cl(_g1h, &pss);
- G1ParScanPartialArrayClosure partial_scan_cl(_g1h, &pss);
+ G1ParScanThreadState pss(_g1h, i);
+ G1ParScanHeapEvacClosure scan_evac_cl(_g1h, &pss);
+ G1ParScanHeapEvacFailureClosure evac_failure_cl(_g1h, &pss);
+ G1ParScanPartialArrayClosure partial_scan_cl(_g1h, &pss);
pss.set_evac_closure(&scan_evac_cl);
pss.set_evac_failure_closure(&evac_failure_cl);
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -247,6 +247,27 @@
NumberSeq _pop_obj_rc_at_copy;
void print_popularity_summary_info() const;
+ // This is used for a quick test on whether a reference points into
+ // the collection set or not. Basically, we have an array, with one
+ // byte per region, and that byte denotes whether the corresponding
+ // region is in the collection set or not. The entry corresponding
+ // the bottom of the heap, i.e., region 0, is pointed to by
+ // _in_cset_fast_test_base. The _in_cset_fast_test field has been
+ // biased so that it actually points to address 0 of the address
+ // space, to make the test as fast as possible (we can simply shift
+ // the address to address into it, instead of having to subtract the
+ // bottom of the heap from the address before shifting it; basically
+ // it works in the same way the card table works).
+ bool* _in_cset_fast_test;
+
+ // The allocated array used for the fast test on whether a reference
+ // points into the collection set or not. This field is also used to
+ // free the array.
+ bool* _in_cset_fast_test_base;
+
+ // The length of the _in_cset_fast_test_base array.
+ size_t _in_cset_fast_test_length;
+
volatile unsigned _gc_time_stamp;
size_t* _surviving_young_words;
@@ -368,6 +389,38 @@
virtual void gc_prologue(bool full);
virtual void gc_epilogue(bool full);
+ // We register a region with the fast "in collection set" test. We
+ // simply set to true the array slot corresponding to this region.
+ void register_region_with_in_cset_fast_test(HeapRegion* r) {
+ assert(_in_cset_fast_test_base != NULL, "sanity");
+ assert(r->in_collection_set(), "invariant");
+ int index = r->hrs_index();
+ assert(0 <= (size_t) index && (size_t) index < _in_cset_fast_test_length,
+ "invariant");
+ assert(!_in_cset_fast_test_base[index], "invariant");
+ _in_cset_fast_test_base[index] = true;
+ }
+
+ // This is a fast test on whether a reference points into the
+ // collection set or not. It does not assume that the reference
+ // points into the heap; if it doesn't, it will return false.
+ bool in_cset_fast_test(oop obj) {
+ assert(_in_cset_fast_test != NULL, "sanity");
+ if (_g1_committed.contains((HeapWord*) obj)) {
+ // no need to subtract the bottom of the heap from obj,
+ // _in_cset_fast_test is biased
+ size_t index = ((size_t) obj) >> HeapRegion::LogOfHRGrainBytes;
+ bool ret = _in_cset_fast_test[index];
+ // let's make sure the result is consistent with what the slower
+ // test returns
+ assert( ret || !obj_in_cs(obj), "sanity");
+ assert(!ret || obj_in_cs(obj), "sanity");
+ return ret;
+ } else {
+ return false;
+ }
+ }
+
protected:
// Shrink the garbage-first heap by at most the given size (in bytes!).
@@ -850,6 +903,7 @@
// Iterate over all objects, calling "cl.do_object" on each.
virtual void object_iterate(ObjectClosure* cl);
+ virtual void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }
// Iterate over all objects allocated since the last collection, calling
// "cl.do_object" on each. The heap must have been initialized properly
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -36,8 +36,11 @@
inline HeapRegion*
G1CollectedHeap::heap_region_containing_raw(const void* addr) const {
- HeapRegion* res = _hrs->addr_to_region(addr);
- assert(res != NULL, "addr outside of heap?");
+ assert(_g1_reserved.contains(addr), "invariant");
+ size_t index = ((intptr_t) addr - (intptr_t) _g1_reserved.start())
+ >> HeapRegion::LogOfHRGrainBytes;
+ HeapRegion* res = _hrs->at(index);
+ assert(res == _hrs->addr_to_region(addr), "sanity");
return res;
}
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -2985,6 +2985,7 @@
_collection_set = hr;
_collection_set_size++;
_collection_set_bytes_used_before += hr->used();
+ _g1->register_region_with_in_cset_fast_test(hr);
}
void
--- a/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -77,6 +77,18 @@
#define G1_PARTIAL_ARRAY_MASK 1
+inline bool has_partial_array_mask(oop* ref) {
+ return (intptr_t) ref & G1_PARTIAL_ARRAY_MASK;
+}
+
+inline oop* set_partial_array_mask(oop obj) {
+ return (oop*) ((intptr_t) obj | G1_PARTIAL_ARRAY_MASK);
+}
+
+inline oop clear_partial_array_mask(oop* ref) {
+ return oop((intptr_t) ref & ~G1_PARTIAL_ARRAY_MASK);
+}
+
class G1ParScanPartialArrayClosure : public G1ParClosureSuper {
G1ParScanClosure _scanner;
template <class T> void process_array_chunk(oop obj, int start, int end);
@@ -101,7 +113,8 @@
G1ParClosureSuper(g1, par_scan_state), _scanner(scanner) { }
};
-template<bool do_gen_barrier, G1Barrier barrier, bool do_mark_forwardee>
+template<bool do_gen_barrier, G1Barrier barrier,
+ bool do_mark_forwardee, bool skip_cset_test>
class G1ParCopyClosure : public G1ParCopyHelper {
G1ParScanClosure _scanner;
void do_oop_work(oop* p);
@@ -119,14 +132,22 @@
virtual void do_oop(narrowOop* p) { do_oop_nv(p); }
};
-typedef G1ParCopyClosure<false, G1BarrierNone, false> G1ParScanExtRootClosure;
-typedef G1ParCopyClosure<true, G1BarrierNone, false> G1ParScanPermClosure;
-typedef G1ParCopyClosure<false, G1BarrierNone, true> G1ParScanAndMarkExtRootClosure;
-typedef G1ParCopyClosure<true, G1BarrierNone, true> G1ParScanAndMarkPermClosure;
-typedef G1ParCopyClosure<false, G1BarrierRS, false> G1ParScanHeapRSClosure;
-typedef G1ParCopyClosure<false, G1BarrierRS, true> G1ParScanAndMarkHeapRSClosure;
-typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacClosure;
-
+typedef G1ParCopyClosure<false, G1BarrierNone, false, false> G1ParScanExtRootClosure;
+typedef G1ParCopyClosure<true, G1BarrierNone, false, false> G1ParScanPermClosure;
+typedef G1ParCopyClosure<false, G1BarrierNone, true, false> G1ParScanAndMarkExtRootClosure;
+typedef G1ParCopyClosure<true, G1BarrierNone, true, false> G1ParScanAndMarkPermClosure;
+typedef G1ParCopyClosure<false, G1BarrierRS, false, false> G1ParScanHeapRSClosure;
+typedef G1ParCopyClosure<false, G1BarrierRS, true, false> G1ParScanAndMarkHeapRSClosure;
+// This is the only case when we set skip_cset_test. Basically, this
+// closure is (should?) only be called directly while we're draining
+// the overflow and task queues. In that case we know that the
+// reference in question points into the collection set, otherwise we
+// would not have pushed it on the queue.
+typedef G1ParCopyClosure<false, G1BarrierEvac, false, true> G1ParScanHeapEvacClosure;
+// We need a separate closure to handle references during evacuation
+// failure processing, as it cannot asume that the reference already
+ // points to the collection set (like G1ParScanHeapEvacClosure does).
+typedef G1ParCopyClosure<false, G1BarrierEvac, false, false> G1ParScanHeapEvacFailureClosure;
class FilterIntoCSClosure: public OopClosure {
G1CollectedHeap* _g1;
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -28,7 +28,7 @@
#define G1_FLAGS(develop, develop_pd, product, product_pd, diagnostic, experimental, notproduct, manageable, product_rw) \
\
- product(intx, ParallelGCG1AllocBufferSize, 4*K, \
+ product(intx, ParallelGCG1AllocBufferSize, 8*K, \
"Size of parallel G1 allocation buffers in to-space.") \
\
product(intx, G1TimeSliceMS, 500, \
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_specialized_oop_closures.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_specialized_oop_closures.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -32,11 +32,13 @@
G1BarrierNone, G1BarrierRS, G1BarrierEvac
};
-template<bool do_gen_barrier, G1Barrier barrier, bool do_mark_forwardee>
+template<bool do_gen_barrier, G1Barrier barrier,
+ bool do_mark_forwardee, bool skip_cset_test>
class G1ParCopyClosure;
class G1ParScanClosure;
-typedef G1ParCopyClosure<false, G1BarrierEvac, false> G1ParScanHeapEvacClosure;
+typedef G1ParCopyClosure<false, G1BarrierEvac, false, true>
+ G1ParScanHeapEvacClosure;
class FilterIntoCSClosure;
class FilterOutOfRegionClosure;
--- a/hotspot/src/share/vm/gc_implementation/includeDB_gc_g1 Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/includeDB_gc_g1 Fri Jan 23 10:41:28 2009 -0500
@@ -31,7 +31,7 @@
cardTableRS.cpp concurrentMark.hpp
cardTableRS.cpp g1SATBCardTableModRefBS.hpp
-collectionSetChooser.cpp g1CollectedHeap.hpp
+collectionSetChooser.cpp g1CollectedHeap.inline.hpp
collectionSetChooser.cpp g1CollectorPolicy.hpp
collectionSetChooser.cpp collectionSetChooser.hpp
collectionSetChooser.cpp space.inline.hpp
@@ -43,7 +43,7 @@
concurrentG1Refine.cpp concurrentG1Refine.hpp
concurrentG1Refine.cpp concurrentG1RefineThread.hpp
concurrentG1Refine.cpp copy.hpp
-concurrentG1Refine.cpp g1CollectedHeap.hpp
+concurrentG1Refine.cpp g1CollectedHeap.inline.hpp
concurrentG1Refine.cpp g1RemSet.hpp
concurrentG1Refine.cpp space.inline.hpp
@@ -51,7 +51,7 @@
concurrentG1RefineThread.cpp concurrentG1Refine.hpp
concurrentG1RefineThread.cpp concurrentG1RefineThread.hpp
-concurrentG1RefineThread.cpp g1CollectedHeap.hpp
+concurrentG1RefineThread.cpp g1CollectedHeap.inline.hpp
concurrentG1RefineThread.cpp g1CollectorPolicy.hpp
concurrentG1RefineThread.cpp handles.inline.hpp
concurrentG1RefineThread.cpp mutexLocker.hpp
@@ -168,7 +168,7 @@
g1CollectorPolicy.cpp concurrentMarkThread.inline.hpp
g1CollectorPolicy.cpp debug.hpp
g1CollectorPolicy.cpp java.hpp
-g1CollectorPolicy.cpp g1CollectedHeap.hpp
+g1CollectorPolicy.cpp g1CollectedHeap.inline.hpp
g1CollectorPolicy.cpp g1CollectorPolicy.hpp
g1CollectorPolicy.cpp heapRegionRemSet.hpp
g1CollectorPolicy.cpp mutexLocker.hpp
@@ -189,7 +189,7 @@
g1MarkSweep.cpp codeCache.hpp
g1MarkSweep.cpp events.hpp
g1MarkSweep.cpp fprofiler.hpp
-g1MarkSweep.hpp g1CollectedHeap.hpp
+g1MarkSweep.hpp g1CollectedHeap.inline.hpp
g1MarkSweep.cpp g1MarkSweep.hpp
g1MarkSweep.cpp gcLocker.hpp
g1MarkSweep.cpp genCollectedHeap.hpp
@@ -285,7 +285,7 @@
heapRegionRemSet.cpp space.inline.hpp
heapRegionSeq.cpp allocation.hpp
-heapRegionSeq.cpp g1CollectedHeap.hpp
+heapRegionSeq.cpp g1CollectedHeap.inline.hpp
heapRegionSeq.cpp heapRegionSeq.hpp
heapRegionSeq.hpp growableArray.hpp
@@ -336,18 +336,18 @@
survRateGroup.hpp numberSeq.hpp
survRateGroup.cpp allocation.hpp
-survRateGroup.cpp g1CollectedHeap.hpp
+survRateGroup.cpp g1CollectedHeap.inline.hpp
survRateGroup.cpp g1CollectorPolicy.hpp
survRateGroup.cpp heapRegion.hpp
survRateGroup.cpp survRateGroup.hpp
thread.cpp concurrentMarkThread.inline.hpp
-universe.cpp g1CollectedHeap.hpp
+universe.cpp g1CollectedHeap.inline.hpp
universe.cpp g1CollectorPolicy.hpp
vm_operations_g1.hpp vmGCOperations.hpp
vm_operations_g1.cpp vm_operations_g1.hpp
-vm_operations_g1.cpp g1CollectedHeap.hpp
+vm_operations_g1.cpp g1CollectedHeap.inline.hpp
vm_operations_g1.cpp isGCActiveMark.hpp
--- a/hotspot/src/share/vm/gc_implementation/includeDB_gc_shared Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/includeDB_gc_shared Fri Jan 23 10:41:28 2009 -0500
@@ -100,4 +100,4 @@
spaceCounters.hpp perfData.hpp
spaceCounters.hpp generationCounters.hpp
-vmGCOperations.cpp g1CollectedHeap.hpp
+vmGCOperations.cpp g1CollectedHeap.inline.hpp
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -200,6 +200,7 @@
void oop_iterate(OopClosure* cl);
void object_iterate(ObjectClosure* cl);
+ void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }
void permanent_oop_iterate(OopClosure* cl);
void permanent_object_iterate(ObjectClosure* cl);
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -466,6 +466,10 @@
// This includes objects in permanent memory.
virtual void object_iterate(ObjectClosure* cl) = 0;
+ // Similar to object_iterate() except iterates only
+ // over live objects.
+ virtual void safe_object_iterate(ObjectClosure* cl) = 0;
+
// Behaves the same as oop_iterate, except only traverses
// interior pointers contained in permanent memory. If there
// is no permanent memory, does nothing.
--- a/hotspot/src/share/vm/memory/genCollectedHeap.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -910,6 +910,13 @@
perm_gen()->object_iterate(cl);
}
+void GenCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
+ for (int i = 0; i < _n_gens; i++) {
+ _gens[i]->safe_object_iterate(cl);
+ }
+ perm_gen()->safe_object_iterate(cl);
+}
+
void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
for (int i = 0; i < _n_gens; i++) {
_gens[i]->object_iterate_since_last_GC(cl);
--- a/hotspot/src/share/vm/memory/genCollectedHeap.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -215,6 +215,7 @@
void oop_iterate(OopClosure* cl);
void oop_iterate(MemRegion mr, OopClosure* cl);
void object_iterate(ObjectClosure* cl);
+ void safe_object_iterate(ObjectClosure* cl);
void object_iterate_since_last_GC(ObjectClosure* cl);
Space* space_containing(const void* addr) const;
--- a/hotspot/src/share/vm/memory/generation.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/generation.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -319,6 +319,21 @@
space_iterate(&blk);
}
+class GenerationSafeObjIterateClosure : public SpaceClosure {
+ private:
+ ObjectClosure* _cl;
+ public:
+ virtual void do_space(Space* s) {
+ s->safe_object_iterate(_cl);
+ }
+ GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
+};
+
+void Generation::safe_object_iterate(ObjectClosure* cl) {
+ GenerationSafeObjIterateClosure blk(cl);
+ space_iterate(&blk);
+}
+
void Generation::prepare_for_compaction(CompactPoint* cp) {
// Generic implementation, can be specialized
CompactibleSpace* space = first_compaction_space();
--- a/hotspot/src/share/vm/memory/generation.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/generation.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -518,6 +518,11 @@
// each.
virtual void object_iterate(ObjectClosure* cl);
+ // Iterate over all safe objects in the generation, calling "cl.do_object" on
+ // each. An object is safe if its references point to other objects in
+ // the heap. This defaults to object_iterate() unless overridden.
+ virtual void safe_object_iterate(ObjectClosure* cl);
+
// Iterate over all objects allocated in the generation since the last
// collection, calling "cl.do_object" on each. The generation must have
// been initialized properly to support this function, or else this call
--- a/hotspot/src/share/vm/memory/heapInspection.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/heapInspection.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -263,6 +263,9 @@
if (!cit.allocation_failed()) {
// Iterate over objects in the heap
RecordInstanceClosure ric(&cit);
+ // If this operation encounters a bad object when using CMS,
+ // consider using safe_object_iterate() which avoids perm gen
+ // objects that may contain bad references.
Universe::heap()->object_iterate(&ric);
// Report if certain classes are not counted because of
@@ -317,5 +320,8 @@
// Iterate over objects in the heap
FindInstanceClosure fic(k, result);
+ // If this operation encounters a bad object when using CMS,
+ // consider using safe_object_iterate() which avoids perm gen
+ // objects that may contain bad references.
Universe::heap()->object_iterate(&fic);
}
--- a/hotspot/src/share/vm/memory/oopFactory.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/oopFactory.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -82,9 +82,11 @@
}
-constantPoolOop oopFactory::new_constantPool(int length, TRAPS) {
+constantPoolOop oopFactory::new_constantPool(int length,
+ bool is_conc_safe,
+ TRAPS) {
constantPoolKlass* ck = constantPoolKlass::cast(Universe::constantPoolKlassObj());
- return ck->allocate(length, CHECK_NULL);
+ return ck->allocate(length, is_conc_safe, CHECK_NULL);
}
@@ -105,11 +107,13 @@
int compressed_line_number_size,
int localvariable_table_length,
int checked_exceptions_length,
+ bool is_conc_safe,
TRAPS) {
klassOop cmkObj = Universe::constMethodKlassObj();
constMethodKlass* cmk = constMethodKlass::cast(cmkObj);
return cmk->allocate(byte_code_size, compressed_line_number_size,
localvariable_table_length, checked_exceptions_length,
+ is_conc_safe,
CHECK_NULL);
}
@@ -117,14 +121,17 @@
methodOop oopFactory::new_method(int byte_code_size, AccessFlags access_flags,
int compressed_line_number_size,
int localvariable_table_length,
- int checked_exceptions_length, TRAPS) {
+ int checked_exceptions_length,
+ bool is_conc_safe,
+ TRAPS) {
methodKlass* mk = methodKlass::cast(Universe::methodKlassObj());
assert(!access_flags.is_native() || byte_code_size == 0,
"native methods should not contain byte codes");
constMethodOop cm = new_constMethod(byte_code_size,
compressed_line_number_size,
localvariable_table_length,
- checked_exceptions_length, CHECK_NULL);
+ checked_exceptions_length,
+ is_conc_safe, CHECK_NULL);
constMethodHandle rw(THREAD, cm);
return mk->allocate(rw, access_flags, CHECK_NULL);
}
--- a/hotspot/src/share/vm/memory/oopFactory.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/oopFactory.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -81,7 +81,9 @@
static symbolHandle new_symbol_handle(const char* name, TRAPS) { return new_symbol_handle(name, (int)strlen(name), CHECK_(symbolHandle())); }
// Constant pools
- static constantPoolOop new_constantPool (int length, TRAPS);
+ static constantPoolOop new_constantPool (int length,
+ bool is_conc_safe,
+ TRAPS);
static constantPoolCacheOop new_constantPoolCache(int length, TRAPS);
// Instance classes
@@ -93,9 +95,20 @@
static constMethodOop new_constMethod(int byte_code_size,
int compressed_line_number_size,
int localvariable_table_length,
- int checked_exceptions_length, TRAPS);
+ int checked_exceptions_length,
+ bool is_conc_safe,
+ TRAPS);
public:
- static methodOop new_method(int byte_code_size, AccessFlags access_flags, int compressed_line_number_size, int localvariable_table_length, int checked_exceptions_length, TRAPS);
+ // Set is_conc_safe for methods which cannot safely be
+ // processed by concurrent GC even after the return of
+ // the method.
+ static methodOop new_method(int byte_code_size,
+ AccessFlags access_flags,
+ int compressed_line_number_size,
+ int localvariable_table_length,
+ int checked_exceptions_length,
+ bool is_conc_safe,
+ TRAPS);
// Method Data containers
static methodDataOop new_methodData(methodHandle method, TRAPS);
--- a/hotspot/src/share/vm/memory/space.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/space.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -569,7 +569,15 @@
if (prev > mr.start()) {
region_start_addr = prev;
blk_start_addr = prev;
- assert(blk_start_addr == block_start(region_start_addr), "invariant");
+ // The previous invocation may have pushed "prev" beyond the
+ // last allocated block yet there may be still be blocks
+ // in this region due to a particular coalescing policy.
+ // Relax the assertion so that the case where the unallocated
+ // block is maintained and "prev" is beyond the unallocated
+ // block does not cause the assertion to fire.
+ assert((BlockOffsetArrayUseUnallocatedBlock &&
+ (!is_in(prev))) ||
+ (blk_start_addr == block_start(region_start_addr)), "invariant");
} else {
region_start_addr = mr.start();
blk_start_addr = block_start(region_start_addr);
@@ -705,6 +713,12 @@
object_iterate_from(bm, blk);
}
+// For a continguous space object_iterate() and safe_object_iterate()
+// are the same.
+void ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
+ object_iterate(blk);
+}
+
void ContiguousSpace::object_iterate_from(WaterMark mark, ObjectClosure* blk) {
assert(mark.space() == this, "Mark does not match space");
HeapWord* p = mark.point();
--- a/hotspot/src/share/vm/memory/space.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/memory/space.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -193,6 +193,9 @@
// each. Objects allocated by applications of the closure are not
// included in the iteration.
virtual void object_iterate(ObjectClosure* blk) = 0;
+ // Similar to object_iterate() except only iterates over
+ // objects whose internal references point to objects in the space.
+ virtual void safe_object_iterate(ObjectClosure* blk) = 0;
// Iterate over all objects that intersect with mr, calling "cl->do_object"
// on each. There is an exception to this: if this closure has already
@@ -843,6 +846,9 @@
void oop_iterate(OopClosure* cl);
void oop_iterate(MemRegion mr, OopClosure* cl);
void object_iterate(ObjectClosure* blk);
+ // For contiguous spaces this method will iterate safely over objects
+ // in the space (i.e., between bottom and top) when at a safepoint.
+ void safe_object_iterate(ObjectClosure* blk);
void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
// iterates on objects up to the safe limit
HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
--- a/hotspot/src/share/vm/oops/constMethodKlass.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constMethodKlass.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -49,10 +49,16 @@
return constMethodOop(obj)->object_is_parsable();
}
+bool constMethodKlass::oop_is_conc_safe(oop obj) const {
+ assert(obj->is_constMethod(), "must be constMethod oop");
+ return constMethodOop(obj)->is_conc_safe();
+}
+
constMethodOop constMethodKlass::allocate(int byte_code_size,
int compressed_line_number_size,
int localvariable_table_length,
int checked_exceptions_length,
+ bool is_conc_safe,
TRAPS) {
int size = constMethodOopDesc::object_size(byte_code_size,
@@ -75,6 +81,7 @@
compressed_line_number_size,
localvariable_table_length);
assert(cm->size() == size, "wrong size for object");
+ cm->set_is_conc_safe(is_conc_safe);
cm->set_partially_loaded();
assert(cm->is_parsable(), "Is safely parsable by gc");
return cm;
--- a/hotspot/src/share/vm/oops/constMethodKlass.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constMethodKlass.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -32,12 +32,16 @@
// Testing
bool oop_is_constMethod() const { return true; }
virtual bool oop_is_parsable(oop obj) const;
+ virtual bool oop_is_conc_safe(oop obj) const;
+
// Allocation
DEFINE_ALLOCATE_PERMANENT(constMethodKlass);
constMethodOop allocate(int byte_code_size, int compressed_line_number_size,
int localvariable_table_length,
- int checked_exceptions_length, TRAPS);
+ int checked_exceptions_length,
+ bool is_conc_safe,
+ TRAPS);
static klassOop create_klass(TRAPS);
// Sizing
--- a/hotspot/src/share/vm/oops/constMethodOop.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constMethodOop.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -104,6 +104,7 @@
// loads and stores. This value may updated and read without a lock by
// multiple threads, so is volatile.
volatile uint64_t _fingerprint;
+ volatile bool _is_conc_safe; // if true, safe for concurrent GC processing
public:
oop* oop_block_beg() const { return adr_method(); }
@@ -273,6 +274,8 @@
oop* adr_method() const { return (oop*)&_method; }
oop* adr_stackmap_data() const { return (oop*)&_stackmap_data; }
oop* adr_exception_table() const { return (oop*)&_exception_table; }
+ bool is_conc_safe() { return _is_conc_safe; }
+ void set_is_conc_safe(bool v) { _is_conc_safe = v; }
// Unique id for the method
static const u2 MAX_IDNUM;
--- a/hotspot/src/share/vm/oops/constantPoolKlass.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constantPoolKlass.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -25,7 +25,7 @@
# include "incls/_precompiled.incl"
# include "incls/_constantPoolKlass.cpp.incl"
-constantPoolOop constantPoolKlass::allocate(int length, TRAPS) {
+constantPoolOop constantPoolKlass::allocate(int length, bool is_conc_safe, TRAPS) {
int size = constantPoolOopDesc::object_size(length);
KlassHandle klass (THREAD, as_klassOop());
constantPoolOop c =
@@ -38,6 +38,9 @@
c->set_flags(0);
// only set to non-zero if constant pool is merged by RedefineClasses
c->set_orig_length(0);
+ // if constant pool may change during RedefineClasses, it is created
+ // unsafe for GC concurrent processing.
+ c->set_is_conc_safe(is_conc_safe);
// all fields are initialized; needed for GC
// initialize tag array
@@ -207,6 +210,11 @@
return size;
}
+bool constantPoolKlass::oop_is_conc_safe(oop obj) const {
+ assert(obj->is_constantPool(), "must be constantPool");
+ return constantPoolOop(obj)->is_conc_safe();
+}
+
#ifndef SERIALGC
int constantPoolKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
assert (obj->is_constantPool(), "obj must be constant pool");
--- a/hotspot/src/share/vm/oops/constantPoolKlass.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constantPoolKlass.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -34,7 +34,7 @@
// Allocation
DEFINE_ALLOCATE_PERMANENT(constantPoolKlass);
- constantPoolOop allocate(int length, TRAPS);
+ constantPoolOop allocate(int length, bool is_conc_safe, TRAPS);
static klassOop create_klass(TRAPS);
// Casting from klassOop
@@ -48,6 +48,8 @@
int object_size() const { return align_object_size(header_size()); }
// Garbage collection
+ // Returns true is the object is safe for GC concurrent processing.
+ virtual bool oop_is_conc_safe(oop obj) const;
void oop_follow_contents(oop obj);
int oop_adjust_pointers(oop obj);
--- a/hotspot/src/share/vm/oops/constantPoolOop.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/constantPoolOop.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -43,6 +43,8 @@
klassOop _pool_holder; // the corresponding class
int _flags; // a few header bits to describe contents for GC
int _length; // number of elements in the array
+ volatile bool _is_conc_safe; // if true, safe for concurrent
+ // GC processing
// only set to non-zero if constant pool is merged by RedefineClasses
int _orig_length;
@@ -379,6 +381,9 @@
static int object_size(int length) { return align_object_size(header_size() + length); }
int object_size() { return object_size(length()); }
+ bool is_conc_safe() { return _is_conc_safe; }
+ void set_is_conc_safe(bool v) { _is_conc_safe = v; }
+
friend class constantPoolKlass;
friend class ClassFileParser;
friend class SystemDictionary;
--- a/hotspot/src/share/vm/oops/klass.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/klass.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -606,8 +606,19 @@
#undef assert_same_query
// Unless overridden, oop is parsable if it has a klass pointer.
+ // Parsability of an object is object specific.
virtual bool oop_is_parsable(oop obj) const { return true; }
+ // Unless overridden, oop is safe for concurrent GC processing
+ // after its allocation is complete. The exception to
+ // this is the case where objects are changed after allocation.
+ // Class redefinition is one of the known exceptions. During
+ // class redefinition, an allocated class can changed in order
+ // order to create a merged class (the combiniation of the
+ // old class definition that has to be perserved and the new class
+ // definition which is being created.
+ virtual bool oop_is_conc_safe(oop obj) const { return true; }
+
// Access flags
AccessFlags access_flags() const { return _access_flags; }
void set_access_flags(AccessFlags flags) { _access_flags = flags; }
--- a/hotspot/src/share/vm/oops/methodOop.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/methodOop.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -792,15 +792,34 @@
AccessFlags flags = m->access_flags();
int checked_exceptions_len = m->checked_exceptions_length();
int localvariable_len = m->localvariable_table_length();
- methodOop newm_oop = oopFactory::new_method(new_code_length, flags, new_compressed_linenumber_size, localvariable_len, checked_exceptions_len, CHECK_(methodHandle()));
+ // Allocate newm_oop with the is_conc_safe parameter set
+ // to IsUnsafeConc to indicate that newm_oop is not yet
+ // safe for concurrent processing by a GC.
+ methodOop newm_oop = oopFactory::new_method(new_code_length,
+ flags,
+ new_compressed_linenumber_size,
+ localvariable_len,
+ checked_exceptions_len,
+ IsUnsafeConc,
+ CHECK_(methodHandle()));
methodHandle newm (THREAD, newm_oop);
int new_method_size = newm->method_size();
// Create a shallow copy of methodOopDesc part, but be careful to preserve the new constMethodOop
constMethodOop newcm = newm->constMethod();
int new_const_method_size = newm->constMethod()->object_size();
+
memcpy(newm(), m(), sizeof(methodOopDesc));
// Create shallow copy of constMethodOopDesc, but be careful to preserve the methodOop
+ // is_conc_safe is set to false because that is the value of
+ // is_conc_safe initialzied into newcm and the copy should
+ // not overwrite that value. During the window during which it is
+ // tagged as unsafe, some extra work could be needed during precleaning
+ // or concurrent marking but those phases will be correct. Setting and
+ // resetting is done in preference to a careful copying into newcm to
+ // avoid having to know the precise layout of a constMethodOop.
+ m->constMethod()->set_is_conc_safe(false);
memcpy(newcm, m->constMethod(), sizeof(constMethodOopDesc));
+ m->constMethod()->set_is_conc_safe(true);
// Reset correct method/const method, method size, and parameter info
newcm->set_method(newm());
newm->set_constMethod(newcm);
@@ -831,6 +850,10 @@
m->localvariable_table_start(),
localvariable_len * sizeof(LocalVariableTableElement));
}
+
+ // Only set is_conc_safe to true when changes to newcm are
+ // complete.
+ newcm->set_is_conc_safe(true);
return newm;
}
--- a/hotspot/src/share/vm/oops/methodOop.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/methodOop.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -129,6 +129,10 @@
volatile address _from_interpreted_entry; // Cache of _code ? _adapter->i2c_entry() : _i2i_entry
public:
+
+ static const bool IsUnsafeConc = false;
+ static const bool IsSafeConc = true;
+
// accessors for instance variables
constMethodOop constMethod() const { return _constMethod; }
void set_constMethod(constMethodOop xconst) { oop_store_without_check((oop*)&_constMethod, (oop)xconst); }
--- a/hotspot/src/share/vm/oops/oop.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/oop.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -108,6 +108,13 @@
// installation of their klass pointer.
bool is_parsable();
+ // Some perm gen objects that have been allocated and initialized
+ // can be changed by the VM when not at a safe point (class rededfinition
+ // is an example). Such objects should not be examined by the
+ // concurrent processing of a garbage collector if is_conc_safe()
+ // returns false.
+ bool is_conc_safe();
+
// type test operations (inlined in oop.inline.h)
bool is_instance() const;
bool is_instanceRef() const;
--- a/hotspot/src/share/vm/oops/oop.inline.hpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/oops/oop.inline.hpp Fri Jan 23 10:41:28 2009 -0500
@@ -435,6 +435,10 @@
return blueprint()->oop_is_parsable(this);
}
+inline bool oopDesc::is_conc_safe() {
+ return blueprint()->oop_is_conc_safe(this);
+}
+
inline void update_barrier_set(void* p, oop v) {
assert(oopDesc::bs() != NULL, "Uninitialized bs in oop!");
oopDesc::bs()->write_ref_field(p, v);
--- a/hotspot/src/share/vm/prims/jvmtiRedefineClasses.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/prims/jvmtiRedefineClasses.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -1230,8 +1230,14 @@
// Constant pools are not easily reused so we allocate a new one
// each time.
+ // merge_cp is created unsafe for concurrent GC processing. It
+ // should be marked safe before discarding it because, even if
+ // garbage. If it crosses a card boundary, it may be scanned
+ // in order to find the start of the first complete object on the card.
constantPoolHandle merge_cp(THREAD,
- oopFactory::new_constantPool(merge_cp_length, THREAD));
+ oopFactory::new_constantPool(merge_cp_length,
+ methodOopDesc::IsUnsafeConc,
+ THREAD));
int orig_length = old_cp->orig_length();
if (orig_length == 0) {
// This old_cp is an actual original constant pool. We save
@@ -1274,6 +1280,7 @@
// rewriting so we can't use the old constant pool with the new
// class.
+ merge_cp()->set_is_conc_safe(true);
merge_cp = constantPoolHandle(); // toss the merged constant pool
} else if (old_cp->length() < scratch_cp->length()) {
// The old constant pool has fewer entries than the new constant
@@ -1283,6 +1290,7 @@
// rewriting so we can't use the new constant pool with the old
// class.
+ merge_cp()->set_is_conc_safe(true);
merge_cp = constantPoolHandle(); // toss the merged constant pool
} else {
// The old constant pool has more entries than the new constant
@@ -1296,6 +1304,7 @@
set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
THREAD);
// drop local ref to the merged constant pool
+ merge_cp()->set_is_conc_safe(true);
merge_cp = constantPoolHandle();
}
} else {
@@ -1325,7 +1334,10 @@
// GCed.
set_new_constant_pool(scratch_class, merge_cp, merge_cp_length, true,
THREAD);
+ merge_cp()->set_is_conc_safe(true);
}
+ assert(old_cp()->is_conc_safe(), "Just checking");
+ assert(scratch_cp()->is_conc_safe(), "Just checking");
return JVMTI_ERROR_NONE;
} // end merge_cp_and_rewrite()
@@ -2314,13 +2326,16 @@
// worst case merge situation. We want to associate the minimum
// sized constant pool with the klass to save space.
constantPoolHandle smaller_cp(THREAD,
- oopFactory::new_constantPool(scratch_cp_length, THREAD));
+ oopFactory::new_constantPool(scratch_cp_length,
+ methodOopDesc::IsUnsafeConc,
+ THREAD));
// preserve orig_length() value in the smaller copy
int orig_length = scratch_cp->orig_length();
assert(orig_length != 0, "sanity check");
smaller_cp->set_orig_length(orig_length);
scratch_cp->copy_cp_to(1, scratch_cp_length - 1, smaller_cp, 1, THREAD);
scratch_cp = smaller_cp;
+ smaller_cp()->set_is_conc_safe(true);
}
// attach new constant pool to klass
@@ -2516,6 +2531,7 @@
rewrite_cp_refs_in_stack_map_table(method, THREAD);
} // end for each method
+ assert(scratch_cp()->is_conc_safe(), "Just checking");
} // end set_new_constant_pool()
--- a/hotspot/src/share/vm/prims/jvmtiTagMap.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/prims/jvmtiTagMap.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -1320,6 +1320,9 @@
}
// do the iteration
+ // If this operation encounters a bad object when using CMS,
+ // consider using safe_object_iterate() which avoids perm gen
+ // objects that may contain bad references.
Universe::heap()->object_iterate(_blk);
// when sharing is enabled we must iterate over the shared spaces
--- a/hotspot/src/share/vm/services/heapDumper.cpp Wed Jan 21 11:14:19 2009 -0500
+++ b/hotspot/src/share/vm/services/heapDumper.cpp Fri Jan 23 10:41:28 2009 -0500
@@ -1700,7 +1700,7 @@
// The HPROF_GC_CLASS_DUMP and HPROF_GC_INSTANCE_DUMP are the vast bulk
// of the heap dump.
HeapObjectDumper obj_dumper(this, writer());
- Universe::heap()->object_iterate(&obj_dumper);
+ Universe::heap()->safe_object_iterate(&obj_dumper);
// HPROF_GC_ROOT_THREAD_OBJ + frames + jni locals
do_threads();