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6819891: ParNew: Fix work queue overflow code to deal correctly with +UseCompressedOops

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When using compressed oops, rather than chaining the overflowed grey objects' pre-images through their klass words, we use GC-worker thread-local overflow stacks.

Reviewed-by: jcoomes, jmasa
This commit is contained in:
Y. Srinivas Ramakrishna 2009-03-28 15:47:29 -07:00
parent 74e0691df5
commit 137a679446
4 changed files with 154 additions and 56 deletions
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14
hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp
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@ -3847,7 +3847,7 @@ bool CMSConcMarkingTask::get_work_from_overflow_stack(CMSMarkStack* ovflw_stk,
MutexLockerEx ml(ovflw_stk->par_lock(),
Mutex::_no_safepoint_check_flag);
// Grab up to 1/4 the size of the work queue
size_t num = MIN2((size_t)work_q->max_elems()/4,
size_t num = MIN2((size_t)(work_q->max_elems() - work_q->size())/4,
(size_t)ParGCDesiredObjsFromOverflowList);
num = MIN2(num, ovflw_stk->length());
for (int i = (int) num; i > 0; i--) {
@ -5204,13 +5204,12 @@ CMSParRemarkTask::do_work_steal(int i, Par_MarkRefsIntoAndScanClosure* cl,
NOT_PRODUCT(int num_steals = 0;)
oop obj_to_scan;
CMSBitMap* bm = &(_collector->_markBitMap);
size_t num_from_overflow_list =
MIN2((size_t)work_q->max_elems()/4,
(size_t)ParGCDesiredObjsFromOverflowList);
while (true) {
// Completely finish any left over work from (an) earlier round(s)
cl->trim_queue(0);
size_t num_from_overflow_list = MIN2((size_t)(work_q->max_elems() - work_q->size())/4,
(size_t)ParGCDesiredObjsFromOverflowList);
// Now check if there's any work in the overflow list
if (_collector->par_take_from_overflow_list(num_from_overflow_list,
work_q)) {
@ -5622,13 +5621,12 @@ void CMSRefProcTaskProxy::do_work_steal(int i,
OopTaskQueue* work_q = work_queue(i);
NOT_PRODUCT(int num_steals = 0;)
oop obj_to_scan;
size_t num_from_overflow_list =
MIN2((size_t)work_q->max_elems()/4,
(size_t)ParGCDesiredObjsFromOverflowList);
while (true) {
// Completely finish any left over work from (an) earlier round(s)
drain->trim_queue(0);
size_t num_from_overflow_list = MIN2((size_t)(work_q->max_elems() - work_q->size())/4,
(size_t)ParGCDesiredObjsFromOverflowList);
// Now check if there's any work in the overflow list
if (_collector->par_take_from_overflow_list(num_from_overflow_list,
work_q)) {
@ -9021,7 +9019,7 @@ void ASConcurrentMarkSweepGeneration::shrink_by(size_t desired_bytes) {
// Transfer some number of overflown objects to usual marking
// stack. Return true if some objects were transferred.
bool MarkRefsIntoAndScanClosure::take_from_overflow_list() {
size_t num = MIN2((size_t)_mark_stack->capacity()/4,
size_t num = MIN2((size_t)(_mark_stack->capacity() - _mark_stack->length())/4,
(size_t)ParGCDesiredObjsFromOverflowList);
bool res = _collector->take_from_overflow_list(num, _mark_stack);