# HG changeset patch # User tschatzl # Date 1393425164 -3600 # Node ID 2c2ae9e5f65dc30bdaf9e9fb13adcb87ebe4ca2e # Parent 86b64209f7156ee8809dcc52615f3289f7990966 8035326: Assume non-NULL references in G1CollectedHeap::in_cset_fast_test Summary: 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 diff -r 86b64209f715 -r 2c2ae9e5f65d src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp --- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Feb 26 15:32:40 2014 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Feb 26 15:32:44 2014 +0100 @@ -4794,11 +4794,16 @@ template template void G1ParCopyClosure::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()) { @@ -4821,12 +4826,12 @@ // 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); } } diff -r 86b64209f715 -r 2c2ae9e5f65d src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp --- a/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Feb 26 15:32:40 2014 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Feb 26 15:32:44 2014 +0100 @@ -698,23 +698,20 @@ } // 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(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(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() {