< prev index next > src/hotspot/share/gc/g1/g1ParScanThreadState.cpp
Print this page
return;
}
markWord m = obj->mark();
if (m.is_marked()) {
- obj = cast_to_oop(m.decode_pointer());
+ obj = obj->forwardee(m);
} else {
obj = do_copy_to_survivor_space(region_attr, obj, m);
}
RawAccess<IS_NOT_NULL>::oop_store(p, obj);
MAYBE_INLINE_EVACUATION
void G1ParScanThreadState::do_partial_array(PartialArrayScanTask task) {
oop from_obj = task.to_source_array();
assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
- assert(from_obj->is_objArray(), "must be obj array");
+ assert(from_obj->forward_safe_klass()->is_objArray_klass(), "must be obj array");
assert(from_obj->is_forwarded(), "must be forwarded");
oop to_obj = from_obj->forwardee();
assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
assert(to_obj->is_objArray(), "must be obj array");
MAYBE_INLINE_EVACUATION
void G1ParScanThreadState::start_partial_objarray(G1HeapRegionAttr dest_attr,
oop from_obj,
oop to_obj) {
- assert(from_obj->is_objArray(), "precondition");
+ assert(from_obj->forward_safe_klass()->is_objArray_klass(), "precondition");
assert(from_obj->is_forwarded(), "precondition");
assert(from_obj->forwardee() == to_obj, "precondition");
assert(from_obj != to_obj, "should not be scanning self-forwarded objects");
assert(to_obj->is_objArray(), "precondition");
// young-to-old (promotion) or old-to-old; destination is old in both cases.
return G1HeapRegionAttr::Old;
}
void G1ParScanThreadState::report_promotion_event(G1HeapRegionAttr const dest_attr,
- oop const old, size_t word_sz, uint age,
+ Klass* klass, size_t word_sz, uint age,
HeapWord * const obj_ptr, uint node_index) const {
PLAB* alloc_buf = _plab_allocator->alloc_buffer(dest_attr, node_index);
if (alloc_buf->contains(obj_ptr)) {
- _g1h->gc_tracer_stw()->report_promotion_in_new_plab_event(old->klass(), word_sz * HeapWordSize, age,
+ _g1h->gc_tracer_stw()->report_promotion_in_new_plab_event(klass, word_sz * HeapWordSize, age,
dest_attr.type() == G1HeapRegionAttr::Old,
alloc_buf->word_sz() * HeapWordSize);
} else {
- _g1h->gc_tracer_stw()->report_promotion_outside_plab_event(old->klass(), word_sz * HeapWordSize, age,
+ _g1h->gc_tracer_stw()->report_promotion_outside_plab_event(klass, word_sz * HeapWordSize, age,
dest_attr.type() == G1HeapRegionAttr::Old);
}
}
NOINLINE
HeapWord* G1ParScanThreadState::allocate_copy_slow(G1HeapRegionAttr* dest_attr,
- oop old,
+ Klass* klass,
size_t word_sz,
uint age,
uint node_index) {
HeapWord* obj_ptr = nullptr;
// Try slow-path allocation unless we're allocating old and old is already full.
}
if (obj_ptr != nullptr) {
update_numa_stats(node_index);
if (_g1h->gc_tracer_stw()->should_report_promotion_events()) {
// The events are checked individually as part of the actual commit
- report_promotion_event(*dest_attr, old, word_sz, age, obj_ptr, node_index);
+ report_promotion_event(*dest_attr, klass, word_sz, age, obj_ptr, node_index);
}
}
return obj_ptr;
}
assert(region_attr.is_in_cset(),
"Unexpected region attr type: %s", region_attr.get_type_str());
// Get the klass once. We'll need it again later, and this avoids
// re-decoding when it's compressed.
- Klass* klass = old->klass();
+ // NOTE: With compact headers, it is not safe to load the Klass* from o, because
+ // that would access the mark-word, and the mark-word might change at any time by
+ // concurrent promotion. The promoted mark-word would point to the forwardee, which
+ // may not yet have completed copying. Therefore we must load the Klass* from
+ // the mark-word that we have already loaded. This is safe, because we have checked
+ // that this is not yet forwarded in the caller.
+ Klass* klass = old->forward_safe_klass(old_mark);
const size_t word_sz = old->size_given_klass(klass);
uint age = 0;
G1HeapRegionAttr dest_attr = next_region_attr(region_attr, old_mark, age);
HeapRegion* const from_region = _g1h->heap_region_containing(old);
HeapWord* obj_ptr = _plab_allocator->plab_allocate(dest_attr, word_sz, node_index);
// PLAB allocations should succeed most of the time, so we'll
// normally check against null once and that's it.
if (obj_ptr == nullptr) {
- obj_ptr = allocate_copy_slow(&dest_attr, old, word_sz, age, node_index);
+ obj_ptr = allocate_copy_slow(&dest_attr, klass, word_sz, age, node_index);
if (obj_ptr == nullptr) {
// This will either forward-to-self, or detect that someone else has
// installed a forwarding pointer.
return handle_evacuation_failure_par(old, old_mark, word_sz);
}
NOINLINE
oop G1ParScanThreadState::handle_evacuation_failure_par(oop old, markWord m, size_t word_sz) {
assert(_g1h->is_in_cset(old), "Object " PTR_FORMAT " should be in the CSet", p2i(old));
- oop forward_ptr = old->forward_to_atomic(old, m, memory_order_relaxed);
+ oop forward_ptr = old->forward_to_self_atomic(m, memory_order_relaxed);
if (forward_ptr == nullptr) {
// Forward-to-self succeeded. We are the "owner" of the object.
HeapRegion* r = _g1h->heap_region_containing(old);
if (_evac_failure_regions->record(r->hrm_index())) {
< prev index next >