InCSetState G1ParScanThreadState::next_state(InCSetState const state, markOop const m, uint& age) {
if (state.is_young()) {
age = !m->has_displaced_mark_helper() ? m->age()
: m->displaced_mark_helper()->age();
if (age < _tenuring_threshold) {
return state;
}
}
return dest(state);
}
oop G1ParScanThreadState::copy_to_survivor_space(InCSetState const state,
oop const old,
markOop const old_mark) {
const size_t word_sz = old->size();
HeapRegion* const from_region = _g1h->heap_region_containing_raw(old);
// +1 to make the -1 indexes valid...
const int young_index = from_region->young_index_in_cset()+1;
assert( (from_region->is_young() && young_index > 0) ||
(!from_region->is_young() && young_index == 0), "invariant" );
const AllocationContext_t context = from_region->allocation_context();
uint age = 0;
InCSetState dest_state = next_state(state, old_mark, age);
HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_state, word_sz, context);
// PLAB allocations should succeed most of the time, so we'll
// normally check against NULL once and that's it.
if (obj_ptr == NULL) {
obj_ptr = _plab_allocator->allocate_direct_or_new_plab(dest_state, word_sz, context);
if (obj_ptr == NULL) {
obj_ptr = allocate_in_next_plab(state, &dest_state, word_sz, context);
if (obj_ptr == NULL) {
// This will either forward-to-self, or detect that someone else has
// installed a forwarding pointer.
return handle_evacuation_failure_par(old, old_mark);
}
}
}
assert(obj_ptr != NULL, "when we get here, allocation should have succeeded");
assert(_g1h->is_in_reserved(obj_ptr), "Allocated memory should be in the heap");
#ifndef PRODUCT
// Should this evacuation fail?
if (_g1h->evacuation_should_fail()) {
// Doing this after all the allocation attempts also tests the
// undo_allocation() method too.
_plab_allocator->undo_allocation(dest_state, obj_ptr, word_sz, context);
return handle_evacuation_failure_par(old, old_mark);
}
#endif // !PRODUCT
// We're going to allocate linearly, so might as well prefetch ahead.
Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);
const oop obj = oop(obj_ptr);
const oop forward_ptr = old->forward_to_atomic(obj);
if (forward_ptr == NULL) {
Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz);
if (dest_state.is_young()) {
if (age < markOopDesc::max_age) {
age++;
}
if (old_mark->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(old_mark);
markOop new_mark = old_mark->displaced_mark_helper()->set_age(age);
old_mark->set_displaced_mark_helper(new_mark);
} else {
obj->set_mark(old_mark->set_age(age));
}
age_table()->add(age, word_sz);
} else {
obj->set_mark(old_mark);
}
if (G1StringDedup::is_enabled()) {
const bool is_from_young = state.is_young();
const bool is_to_young = dest_state.is_young();
assert(is_from_young == _g1h->heap_region_containing_raw(old)->is_young(),
"sanity");
assert(is_to_young == _g1h->heap_region_containing_raw(obj)->is_young(),
"sanity");
G1StringDedup::enqueue_from_evacuation(is_from_young,
is_to_young,
_worker_id,
obj);
}
size_t* const surv_young_words = surviving_young_words();
surv_young_words[young_index] += word_sz;
if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) {
// We keep track of the next start index in the length field of
// the to-space object. The actual length can be found in the
// length field of the from-space object.
arrayOop(obj)->set_length(0);
oop* old_p = set_partial_array_mask(old);
push_on_queue(old_p);
} else {
HeapRegion* const to_region = _g1h->heap_region_containing_raw(obj_ptr);
_scanner.set_region(to_region);
obj->oop_iterate_backwards(&_scanner);
}
return obj;
} else {
_plab_allocator->undo_allocation(dest_state, obj_ptr, word_sz, context);
return forward_ptr;
}
}