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8035326: Assume non-NULL references in G1CollectedHeap::in_cset_fast_test

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Remove the assumption that G1CollectedHeap::in_cset_fast_test needs to check for NULL references. Most of the time this is not required, making the code doing this check multiple times.

Reviewed-by: stefank, mgerdin, jmasa
This commit is contained in:
Thomas Schatzl 2014-02-24 09:40:49 +01:00
parent 6c588725c1
commit dbc8581147
2 changed files with 21 additions and 19 deletions
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13
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
View File

@ -4789,11 +4789,16 @@ void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
template <G1Barrier barrier, bool do_mark_object>
template <class T>
void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
oop obj = oopDesc::load_decode_heap_oop(p);
T heap_oop = oopDesc::load_heap_oop(p);
if (oopDesc::is_null(heap_oop)) {
return;
}
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
assert(_worker_id == _par_scan_state->queue_num(), "sanity");
// here the null check is implicit in the cset_fast_test() test
if (_g1->in_cset_fast_test(obj)) {
oop forwardee;
if (obj->is_forwarded()) {
@ -4816,12 +4821,12 @@ void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* p) {
// The object is not in collection set. If we're a root scanning
// closure during an initial mark pause (i.e. do_mark_object will
// be true) then attempt to mark the object.
if (do_mark_object && _g1->is_in_g1_reserved(obj)) {
if (do_mark_object) {
mark_object(obj);
}
}
if (barrier == G1BarrierEvac && obj != NULL) {
if (barrier == G1BarrierEvac) {
_par_scan_state->update_rs(_from, p, _worker_id);
}
}

27
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
View File

@ -698,23 +698,20 @@ public:
}
// 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.
// collection set or not. Assume that the reference
// points into the heap.
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
uintx index = cast_from_oop<uintx>(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;
}
assert(_g1_committed.contains((HeapWord*) obj), err_msg("Given reference outside of heap, is "PTR_FORMAT, (HeapWord*)obj));
// no need to subtract the bottom of the heap from obj,
// _in_cset_fast_test is biased
uintx index = cast_from_oop<uintx>(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;
}
void clear_cset_fast_test() {