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8155257: ParNew/CMS: Clean up promoted object tracking

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Reviewed-by: jmasa, ysr
This commit is contained in:
Antonios Printezis 2016-05-05 08:51:27 -07:00
parent 565780b7aa
commit 80dc8b84bc
4 changed files with 35 additions and 9 deletions
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27
hotspot/src/share/vm/gc/cms/concurrentMarkSweepGeneration.cpp
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@ -1019,7 +1019,7 @@ ConcurrentMarkSweepGeneration::par_promote(int thread_num,
return NULL;
}
}
assert(promoInfo->has_spooling_space(), "Control point invariant");
assert(!promoInfo->tracking() || promoInfo->has_spooling_space(), "Control point invariant");
const size_t alloc_sz = CompactibleFreeListSpace::adjustObjectSize(word_sz);
HeapWord* obj_ptr = ps->lab.alloc(alloc_sz);
if (obj_ptr == NULL) {
@ -1094,6 +1094,12 @@ par_oop_since_save_marks_iterate_done(int thread_num) {
CMSParGCThreadState* ps = _par_gc_thread_states[thread_num];
ParScanWithoutBarrierClosure* dummy_cl = NULL;
ps->promo.promoted_oops_iterate_nv(dummy_cl);
// Because card-scanning has been completed, subsequent phases
// (e.g., reference processing) will not need to recognize which
// objects have been promoted during this GC. So, we can now disable
// promotion tracking.
ps->promo.stopTrackingPromotions();
}
bool ConcurrentMarkSweepGeneration::should_collect(bool full,
@ -2032,6 +2038,12 @@ void ConcurrentMarkSweepGeneration::gc_prologue(bool full) {
_capacity_at_prologue = capacity();
_used_at_prologue = used();
// We enable promotion tracking so that card-scanning can recognize
// which objects have been promoted during this GC and skip them.
for (uint i = 0; i < ParallelGCThreads; i++) {
_par_gc_thread_states[i]->promo.startTrackingPromotions();
}
// Delegate to CMScollector which knows how to coordinate between
// this and any other CMS generations that it is responsible for
// collecting.
@ -2118,9 +2130,15 @@ void CMSCollector::gc_epilogue(bool full) {
void ConcurrentMarkSweepGeneration::gc_epilogue(bool full) {
collector()->gc_epilogue(full);
// Also reset promotion tracking in par gc thread states.
// When using ParNew, promotion tracking should have already been
// disabled. However, the prologue (which enables promotion
// tracking) and epilogue are called irrespective of the type of
// GC. So they will also be called before and after Full GCs, during
// which promotion tracking will not be explicitly disabled. So,
// it's safer to also disable it here too (to be symmetric with
// enabling it in the prologue).
for (uint i = 0; i < ParallelGCThreads; i++) {
_par_gc_thread_states[i]->promo.stopTrackingPromotions(i);
_par_gc_thread_states[i]->promo.stopTrackingPromotions();
}
}
@ -2431,9 +2449,6 @@ void CMSCollector::verify_after_remark_work_2() {
void ConcurrentMarkSweepGeneration::save_marks() {
// delegate to CMS space
cmsSpace()->save_marks();
for (uint i = 0; i < ParallelGCThreads; i++) {
_par_gc_thread_states[i]->promo.startTrackingPromotions();
}
}
bool ConcurrentMarkSweepGeneration::no_allocs_since_save_marks() {