inline HeapRegion* HeapRegionManager::at(uint index) const {
assert(is_available(index), "pre-condition");
HeapRegion* hr = _regions.get_by_index(index);
assert(hr != NULL, "sanity");
assert(hr->hrm_index() == index, "sanity");
return hr;
}
uint HeapRegionManager::find_highest_free(bool* expanded) {
// Loop downwards from the highest region index, looking for an
// entry which is either free or not yet committed. If not yet
// committed, expand_at that index.
uint curr = max_length() - 1;
while (true) {
HeapRegion *hr = _regions.get_by_index(curr);
if (hr == NULL) {
uint res = expand_at(curr, 1);
if (res == 1) {
*expanded = true;
return curr;
}
} else {
if (hr->is_free()) {
*expanded = false;
return curr;
}
}
if (curr == 0) {
return G1_NO_HRM_INDEX;
}
curr--;
}
}
inline HeapRegion* G1CollectedHeap::heap_region_containing(const T addr) const {
HeapRegion* hr = heap_region_containing_raw(addr);
if (hr->is_continues_humongous()) {
return hr->humongous_start_region();
}
return hr;
}
void G1MarkSweep::mark_sweep_phase2() {
// Now all live objects are marked, compute the new object addresses.
// It is imperative that we traverse perm_gen LAST. If dead space is
// allowed a range of dead object may get overwritten by a dead int
// array. If perm_gen is not traversed last a klassOop may get
// overwritten. This is fine since it is dead, but if the class has dead
// instances we have to skip them, and in order to find their size we
// need the klassOop!
//
// It is not required that we traverse spaces in the same order in
// phase2, phase3 and phase4, but the ValidateMarkSweep live oops
// tracking expects us to do so. See comment under phase4.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
Generation* pg = g1h->perm_gen();
EventMark m("2 compute new addresses");
TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty);
GenMarkSweep::trace("2");
FindFirstRegionClosure cl;
g1h->heap_region_iterate(&cl);
HeapRegion *r = cl.result();
CompactibleSpace* sp = r;
if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
sp = r->next_compaction_space();
}
G1PrepareCompactClosure blk(sp);
g1h->heap_region_iterate(&blk);
CompactPoint perm_cp(pg, NULL, NULL);
pg->prepare_for_compaction(&perm_cp);
}
void CSetChooserCache::insert(HeapRegion *hr) {
guarantee(false, "CSetChooserCache::insert(): don't call this any more");
assert(!is_full(), "cache should not be empty");
hr->calc_gc_efficiency();
int empty_index;
if (_occupancy == 0) {
empty_index = _first;
} else {
empty_index = trim_index(_first + _occupancy);
assert(_cache[empty_index] == NULL, "last slot should be empty");
int last_index = trim_index(empty_index - 1);
HeapRegion *last = _cache[last_index];
assert(last != NULL,"as the cache is not empty, last should not be empty");
while (empty_index != _first &&
last->gc_efficiency() < hr->gc_efficiency()) {
_cache[empty_index] = last;
last->set_sort_index(get_sort_index(empty_index));
empty_index = last_index;
last_index = trim_index(last_index - 1);
last = _cache[last_index];
}
}
_cache[empty_index] = hr;
hr->set_sort_index(get_sort_index(empty_index));
++_occupancy;
assert(verify(), "cache should be consistent");
}
oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markOop m) {
assert(_g1h->obj_in_cs(old),
err_msg("Object " PTR_FORMAT " should be in the CSet", p2i(old)));
oop forward_ptr = old->forward_to_atomic(old);
if (forward_ptr == NULL) {
// Forward-to-self succeeded. We are the "owner" of the object.
HeapRegion* r = _g1h->heap_region_containing(old);
if (!r->evacuation_failed()) {
r->set_evacuation_failed(true);
_g1h->hr_printer()->evac_failure(r);
}
_g1h->preserve_mark_during_evac_failure(_worker_id, old, m);
_scanner.set_region(r);
old->oop_iterate_backwards(&_scanner);
return old;
} else {
// Forward-to-self failed. Either someone else managed to allocate
// space for this object (old != forward_ptr) or they beat us in
// self-forwarding it (old == forward_ptr).
assert(old == forward_ptr || !_g1h->obj_in_cs(forward_ptr),
err_msg("Object " PTR_FORMAT " forwarded to: " PTR_FORMAT " "
"should not be in the CSet",
p2i(old), p2i(forward_ptr)));
return forward_ptr;
}
}
void HeapRegionManager::make_regions_available(uint start, uint num_regions) {
guarantee(num_regions > 0, "No point in calling this for zero regions");
commit_regions(start, num_regions);
for (uint i = start; i < start + num_regions; i++) {
if (_regions.get_by_index(i) == NULL) {
HeapRegion* new_hr = new_heap_region(i);
_regions.set_by_index(i, new_hr);
_allocated_heapregions_length = MAX2(_allocated_heapregions_length, i + 1);
}
}
_available_map.par_set_range(start, start + num_regions, BitMap::unknown_range);
for (uint i = start; i < start + num_regions; i++) {
assert(is_available(i), "Just made region %u available but is apparently not.", i);
HeapRegion* hr = at(i);
if (G1CollectedHeap::heap()->hr_printer()->is_active()) {
G1CollectedHeap::heap()->hr_printer()->commit(hr);
}
HeapWord* bottom = G1CollectedHeap::heap()->bottom_addr_for_region(i);
MemRegion mr(bottom, bottom + HeapRegion::GrainWords);
hr->initialize(mr);
insert_into_free_list(at(i));
}
}
inline void G1RemSet::par_write_ref(HeapRegion* from, T* p, uint tid) {
oop obj = oopDesc::load_decode_heap_oop(p);
if (obj == NULL) {
return;
}
#ifdef ASSERT
// can't do because of races
// assert(obj == NULL || obj->is_oop(), "expected an oop");
// Do the safe subset of is_oop
#ifdef CHECK_UNHANDLED_OOPS
oopDesc* o = obj.obj();
#else
oopDesc* o = obj;
#endif // CHECK_UNHANDLED_OOPS
assert((intptr_t)o % MinObjAlignmentInBytes == 0, "not oop aligned");
assert(_g1->is_in_reserved(obj), "must be in heap");
#endif // ASSERT
assert(from == NULL || from->is_in_reserved(p), "p is not in from");
HeapRegion* to = _g1->heap_region_containing(obj);
if (from != to) {
assert(to->rem_set() != NULL, "Need per-region 'into' remsets.");
to->rem_set()->add_reference(p, tid);
}
}
bool G1ArchiveAllocator::alloc_new_region() {
// Allocate the highest free region in the reserved heap,
// and add it to our list of allocated regions. It is marked
// archive and added to the old set.
HeapRegion* hr = _g1h->alloc_highest_free_region();
if (hr == NULL) {
return false;
}
assert(hr->is_empty(), "expected empty region (index %u)", hr->hrm_index());
hr->set_archive();
_g1h->old_set_add(hr);
_g1h->hr_printer()->alloc(hr);
_allocated_regions.append(hr);
_allocation_region = hr;
// Set up _bottom and _max to begin allocating in the lowest
// min_region_size'd chunk of the allocated G1 region.
_bottom = hr->bottom();
_max = _bottom + HeapRegion::min_region_size_in_words();
// Tell mark-sweep that objects in this region are not to be marked.
G1MarkSweep::set_range_archive(MemRegion(_bottom, HeapRegion::GrainWords), true);
// Since we've modified the old set, call update_sizes.
_g1h->g1mm()->update_sizes();
return true;
}
uint HeapRegionManager::find_contiguous(size_t num, bool empty_only) {
uint found = 0;
size_t length_found = 0;
uint cur = 0;
while (length_found < num && cur < max_length()) {
HeapRegion* hr = _regions.get_by_index(cur);
if ((!empty_only && !is_available(cur)) || (is_available(cur) && hr != NULL && hr->is_empty())) {
// This region is a potential candidate for allocation into.
length_found++;
} else {
// This region is not a candidate. The next region is the next possible one.
found = cur + 1;
length_found = 0;
}
cur++;
}
if (length_found == num) {
for (uint i = found; i < (found + num); i++) {
HeapRegion* hr = _regions.get_by_index(i);
// sanity check
guarantee((!empty_only && !is_available(i)) || (is_available(i) && hr != NULL && hr->is_empty()),
"Found region sequence starting at " UINT32_FORMAT ", length " SIZE_FORMAT
" that is not empty at " UINT32_FORMAT ". Hr is " PTR_FORMAT, found, num, i, p2i(hr));
}
return found;
} else {
return G1_NO_HRM_INDEX;
}
}
HeapRegion* OldGCAllocRegion::release() {
HeapRegion* cur = get();
if (cur != NULL) {
// Determine how far we are from the next card boundary. If it is smaller than
// the minimum object size we can allocate into, expand into the next card.
HeapWord* top = cur->top();
HeapWord* aligned_top = (HeapWord*)align_ptr_up(top, G1BlockOffsetSharedArray::N_bytes);
size_t to_allocate_words = pointer_delta(aligned_top, top, HeapWordSize);
if (to_allocate_words != 0) {
// We are not at a card boundary. Fill up, possibly into the next, taking the
// end of the region and the minimum object size into account.
to_allocate_words = MIN2(pointer_delta(cur->end(), cur->top(), HeapWordSize),
MAX2(to_allocate_words, G1CollectedHeap::min_fill_size()));
// Skip allocation if there is not enough space to allocate even the smallest
// possible object. In this case this region will not be retained, so the
// original problem cannot occur.
if (to_allocate_words >= G1CollectedHeap::min_fill_size()) {
HeapWord* dummy = attempt_allocation(to_allocate_words, true /* bot_updates */);
CollectedHeap::fill_with_object(dummy, to_allocate_words);
}
}
}
return G1AllocRegion::release();
}
inline HeapRegion* HeapRegionSeq::at(uint index) const {
assert(index < length(), "pre-condition");
HeapRegion* hr = _regions.get_by_index(index);
assert(hr != NULL, "sanity");
assert(hr->hrs_index() == index, "sanity");
return hr;
}
size_t G1CMObjArrayProcessor::process_slice(oop obj) {
HeapWord* const decoded_address = decode_array_slice(obj);
// Find the start address of the objArrayOop.
// Shortcut the BOT access if the given address is from a humongous object. The BOT
// slide is fast enough for "smaller" objects in non-humongous regions, but is slower
// than directly using heap region table.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
HeapRegion* r = g1h->heap_region_containing(decoded_address);
HeapWord* const start_address = r->is_humongous() ?
r->humongous_start_region()->bottom() :
g1h->block_start(decoded_address);
assert(oop(start_address)->is_objArray(), "Address " PTR_FORMAT " does not refer to an object array ", p2i(start_address));
assert(start_address < decoded_address,
"Object start address " PTR_FORMAT " must be smaller than decoded address " PTR_FORMAT,
p2i(start_address),
p2i(decoded_address));
objArrayOop objArray = objArrayOop(start_address);
size_t already_scanned = decoded_address - start_address;
size_t remaining = objArray->size() - already_scanned;
return process_array_slice(objArray, decoded_address, remaining);
}
HeapRegion* allocate_free_region(bool is_old) {
HeapRegion* hr = _free_list.remove_region(is_old);
if (hr != NULL) {
assert(hr->next() == NULL, "Single region should not have next");
assert(is_available(hr->hrm_index()), "Must be committed");
}
return hr;
}
inline HeapRegion*
G1CollectedHeap::heap_region_containing(const T addr) const {
HeapRegion* hr = _hrs.addr_to_region((HeapWord*) addr);
// hr can be null if addr in perm_gen
if (hr != NULL && hr->continuesHumongous()) {
hr = hr->humongous_start_region();
}
return hr;
}
void CSetChooserCache::clear() {
_occupancy = 0;
_first = 0;
for (int i = 0; i < CacheLength; ++i) {
HeapRegion *hr = _cache[i];
if (hr != NULL)
hr->set_sort_index(-1);
_cache[i] = NULL;
}
}
void do_oop_work(T* p) {
_work->do_oop(p);
T oop_or_narrowoop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(oop_or_narrowoop)) {
oop o = oopDesc::decode_heap_oop_not_null(oop_or_narrowoop);
HeapRegion* hr = _g1h->heap_region_containing_raw(o);
assert(!_g1h->obj_in_cs(o) || hr->rem_set()->strong_code_roots_list_contains(_nm), "if o still in CS then evacuation failed and nm must already be in the remset");
hr->add_strong_code_root(_nm);
}
}
inline HeapRegion* FreeRegionList::remove_from_head_impl() {
HeapRegion* result = _head;
_head = result->next();
if (_head == NULL) {
_tail = NULL;
} else {
_head->set_prev(NULL);
}
result->set_next(NULL);
return result;
}
inline HeapRegion* FreeRegionList::remove_from_tail_impl() {
HeapRegion* result = _tail;
_tail = result->prev();
if (_tail == NULL) {
_head = NULL;
} else {
_tail->set_next(NULL);
}
result->set_prev(NULL);
return result;
}
void CollectionSetChooser::clearMarkedHeapRegions() {
for (int i = 0; i < _markedRegions.length(); i++) {
HeapRegion* r = _markedRegions.at(i);
if (r != NULL) {
r->set_sort_index(-1);
}
}
_markedRegions.clear();
_curr_index = 0;
_length = 0;
_remainingReclaimableBytes = 0;
};
virtual size_t used_in_alloc_regions() {
assert(Heap_lock->owner() != NULL,
"Should be owned on this thread's behalf.");
size_t result = 0;
// Read only once in case it is set to NULL concurrently
HeapRegion* hr = mutator_alloc_region(AllocationContext::current())->get();
if (hr != NULL) {
result += hr->used();
}
return result;
}
HeapRegion* HRInto_G1RemSet::calculateStartRegion(int worker_i) {
HeapRegion* result = _g1p->collection_set();
if (ParallelGCThreads > 0) {
size_t cs_size = _g1p->collection_set_size();
int n_workers = _g1->workers()->total_workers();
size_t cs_spans = cs_size / n_workers;
size_t ind = cs_spans * worker_i;
for (size_t i = 0; i < ind; i++)
result = result->next_in_collection_set();
}
return result;
}
template <class T> inline void FilterAndMarkInHeapRegionAndIntoCSClosure::do_oop_nv(T* p) {
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
HeapRegion* hr = _g1->heap_region_containing((HeapWord*) obj);
if (hr != NULL) {
if (hr->in_collection_set())
_oc->do_oop(p);
else if (!hr->is_young())
_cm->grayRoot(obj);
}
}
}
bool CollectionSetChooser::verify() {
guarantee(_length >= 0, err_msg("_length: %d", _length));
guarantee(0 <= _curr_index && _curr_index <= _length,
err_msg("_curr_index: %d _length: %d", _curr_index, _length));
int index = 0;
size_t sum_of_reclaimable_bytes = 0;
while (index < _curr_index) {
guarantee(_markedRegions.at(index) == NULL,
"all entries before _curr_index should be NULL");
index += 1;
}
HeapRegion *prev = NULL;
while (index < _length) {
HeapRegion *curr = _markedRegions.at(index++);
guarantee(curr != NULL, "Regions in _markedRegions array cannot be NULL");
int si = curr->sort_index();
guarantee(!curr->is_young(), "should not be young!");
guarantee(!curr->isHumongous(), "should not be humongous!");
guarantee(si > -1 && si == (index-1), "sort index invariant");
if (prev != NULL) {
guarantee(orderRegions(prev, curr) != 1,
err_msg("GC eff prev: %1.4f GC eff curr: %1.4f",
prev->gc_efficiency(), curr->gc_efficiency()));
}
sum_of_reclaimable_bytes += curr->reclaimable_bytes();
prev = curr;
}
guarantee(sum_of_reclaimable_bytes == _remainingReclaimableBytes,
err_msg("reclaimable bytes inconsistent, "
"remaining: "SIZE_FORMAT" sum: "SIZE_FORMAT,
_remainingReclaimableBytes, sum_of_reclaimable_bytes));
return true;
}
CompactibleSpace* HeapRegion::next_compaction_space() const {
// We're not using an iterator given that it will wrap around when
// it reaches the last region and this is not what we want here.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
uint index = hrs_index() + 1;
while (index < g1h->n_regions()) {
HeapRegion* hr = g1h->region_at(index);
if (!hr->isHumongous()) {
return hr;
}
index += 1;
}
return NULL;
}
void HRInto_G1RemSet::concurrentRefineOneCard_impl(jbyte* card_ptr, int worker_i) {
// Construct the region representing the card.
HeapWord* start = _ct_bs->addr_for(card_ptr);
// And find the region containing it.
HeapRegion* r = _g1->heap_region_containing(start);
assert(r != NULL, "unexpected null");
HeapWord* end = _ct_bs->addr_for(card_ptr + 1);
MemRegion dirtyRegion(start, end);
#if CARD_REPEAT_HISTO
init_ct_freq_table(_g1->g1_reserved_obj_bytes());
ct_freq_note_card(_ct_bs->index_for(start));
#endif
UpdateRSOopClosure update_rs_oop_cl(this, worker_i);
update_rs_oop_cl.set_from(r);
FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl);
// Undirty the card.
*card_ptr = CardTableModRefBS::clean_card_val();
// We must complete this write before we do any of the reads below.
OrderAccess::storeload();
// And process it, being careful of unallocated portions of TLAB's.
HeapWord* stop_point =
r->oops_on_card_seq_iterate_careful(dirtyRegion,
&filter_then_update_rs_oop_cl);
// If stop_point is non-null, then we encountered an unallocated region
// (perhaps the unfilled portion of a TLAB.) For now, we'll dirty the
// card and re-enqueue: if we put off the card until a GC pause, then the
// unallocated portion will be filled in. Alternatively, we might try
// the full complexity of the technique used in "regular" precleaning.
if (stop_point != NULL) {
// The card might have gotten re-dirtied and re-enqueued while we
// worked. (In fact, it's pretty likely.)
if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
*card_ptr = CardTableModRefBS::dirty_card_val();
MutexLockerEx x(Shared_DirtyCardQ_lock,
Mutex::_no_safepoint_check_flag);
DirtyCardQueue* sdcq =
JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
sdcq->enqueue(card_ptr);
}
} else {
out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region());
_conc_refine_cards++;
}
}
size_t G1Allocator::unsafe_max_tlab_alloc(AllocationContext_t context) {
// Return the remaining space in the cur alloc region, but not less than
// the min TLAB size.
// Also, this value can be at most the humongous object threshold,
// since we can't allow tlabs to grow big enough to accommodate
// humongous objects.
HeapRegion* hr = mutator_alloc_region(context)->get();
size_t max_tlab = _g1h->max_tlab_size() * wordSize;
if (hr == NULL) {
return max_tlab;
} else {
return MIN2(MAX2(hr->free(), (size_t) MinTLABSize), max_tlab);
}
}
inline bool requires_marking(const void* entry, G1CollectedHeap* heap) {
// Includes rejection of NULL pointers.
assert(heap->is_in_reserved(entry),
err_msg("Non-heap pointer in SATB buffer: " PTR_FORMAT, p2i(entry)));
HeapRegion* region = heap->heap_region_containing_raw(entry);
assert(region != NULL, err_msg("No region for " PTR_FORMAT, p2i(entry)));
if (entry >= region->next_top_at_mark_start()) {
return false;
}
assert(((oop)entry)->is_oop(true /* ignore mark word */),
err_msg("Invalid oop in SATB buffer: " PTR_FORMAT, p2i(entry)));
return true;
}
HeapRegion *CSetChooserCache::remove_first() {
guarantee(false, "CSetChooserCache::remove_first(): "
"don't call this any more");
if (_occupancy > 0) {
assert(_cache[_first] != NULL, "cache should have at least one region");
HeapRegion *ret = _cache[_first];
_cache[_first] = NULL;
ret->set_sort_index(-1);
--_occupancy;
_first = trim_index(_first + 1);
assert(verify(), "cache should be consistent");
return ret;
} else {
return NULL;
}
}
void CollectionSetChooser::fillCache() {
guarantee(false, "fillCache: don't call this any more");
while (!_cache.is_full() && (_curr_index < _length)) {
HeapRegion* hr = _markedRegions.at(_curr_index);
assert(hr != NULL,
err_msg("Unexpected NULL hr in _markedRegions at index %d",
_curr_index));
_curr_index += 1;
assert(!hr->is_young(), "should not be young!");
assert(hr->sort_index() == _curr_index-1, "sort_index invariant");
_markedRegions.at_put(hr->sort_index(), NULL);
_cache.insert(hr);
assert(!_cache.is_empty(), "cache should not be empty");
}
assert(verify(), "cache should be consistent");
}
