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8058298: Separate heap region iterator claim values from the data structures iterated over

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Reviewed-by: tschatzl, brutisso
This commit is contained in:
Marcus Larsson 2014-10-07 14:54:53 +02:00
parent 18eb46eb95
commit 6d1c35615a
11 changed files with 157 additions and 354 deletions
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102
hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp
View File

@ -1683,6 +1683,8 @@ protected:
int _failures; int _failures;
bool _verbose; bool _verbose;
HeapRegionClaimer _hrclaimer;
public: public:
G1ParVerifyFinalCountTask(G1CollectedHeap* g1h, G1ParVerifyFinalCountTask(G1CollectedHeap* g1h,
BitMap* region_bm, BitMap* card_bm, BitMap* region_bm, BitMap* card_bm,
@ -1692,19 +1694,8 @@ public:
_actual_region_bm(region_bm), _actual_card_bm(card_bm), _actual_region_bm(region_bm), _actual_card_bm(card_bm),
_expected_region_bm(expected_region_bm), _expected_card_bm(expected_card_bm), _expected_region_bm(expected_region_bm), _expected_card_bm(expected_card_bm),
_failures(0), _verbose(false), _failures(0), _verbose(false),
_n_workers(0) { _n_workers(_g1h->workers()->active_workers()), _hrclaimer(_n_workers) {
assert(VerifyDuringGC, "don't call this otherwise"); assert(VerifyDuringGC, "don't call this otherwise");
// Use the value already set as the number of active threads
// in the call to run_task().
if (G1CollectedHeap::use_parallel_gc_threads()) {
assert( _g1h->workers()->active_workers() > 0,
"Should have been previously set");
_n_workers = _g1h->workers()->active_workers();
} else {
_n_workers = 1;
}
assert(_expected_card_bm->size() == _actual_card_bm->size(), "sanity"); assert(_expected_card_bm->size() == _actual_card_bm->size(), "sanity");
assert(_expected_region_bm->size() == _actual_region_bm->size(), "sanity"); assert(_expected_region_bm->size() == _actual_region_bm->size(), "sanity");
@ -1721,10 +1712,7 @@ public:
_verbose); _verbose);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
_g1h->heap_region_par_iterate_chunked(&verify_cl, _g1h->heap_region_par_iterate(&verify_cl, worker_id, &_hrclaimer);
worker_id,
_n_workers,
HeapRegion::VerifyCountClaimValue);
} else { } else {
_g1h->heap_region_iterate(&verify_cl); _g1h->heap_region_iterate(&verify_cl);
} }
@ -1813,22 +1801,14 @@ protected:
BitMap* _actual_card_bm; BitMap* _actual_card_bm;
uint _n_workers; uint _n_workers;
HeapRegionClaimer _hrclaimer;
public: public:
G1ParFinalCountTask(G1CollectedHeap* g1h, BitMap* region_bm, BitMap* card_bm) G1ParFinalCountTask(G1CollectedHeap* g1h, BitMap* region_bm, BitMap* card_bm)
: AbstractGangTask("G1 final counting"), : AbstractGangTask("G1 final counting"),
_g1h(g1h), _cm(_g1h->concurrent_mark()), _g1h(g1h), _cm(_g1h->concurrent_mark()),
_actual_region_bm(region_bm), _actual_card_bm(card_bm), _actual_region_bm(region_bm), _actual_card_bm(card_bm),
_n_workers(0) { _n_workers(_g1h->workers()->active_workers()), _hrclaimer(_n_workers) {
// Use the value already set as the number of active threads
// in the call to run_task().
if (G1CollectedHeap::use_parallel_gc_threads()) {
assert( _g1h->workers()->active_workers() > 0,
"Should have been previously set");
_n_workers = _g1h->workers()->active_workers();
} else {
_n_workers = 1;
}
} }
void work(uint worker_id) { void work(uint worker_id) {
@ -1839,10 +1819,7 @@ public:
_actual_card_bm); _actual_card_bm);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
_g1h->heap_region_par_iterate_chunked(&final_update_cl, _g1h->heap_region_par_iterate(&final_update_cl, worker_id, &_hrclaimer);
worker_id,
_n_workers,
HeapRegion::FinalCountClaimValue);
} else { } else {
_g1h->heap_region_iterate(&final_update_cl); _g1h->heap_region_iterate(&final_update_cl);
} }
@ -1929,12 +1906,12 @@ protected:
size_t _max_live_bytes; size_t _max_live_bytes;
size_t _freed_bytes; size_t _freed_bytes;
FreeRegionList* _cleanup_list; FreeRegionList* _cleanup_list;
HeapRegionClaimer _hrclaimer;
public: public:
G1ParNoteEndTask(G1CollectedHeap* g1h, G1ParNoteEndTask(G1CollectedHeap* g1h, FreeRegionList* cleanup_list, uint n_workers) :
FreeRegionList* cleanup_list) : AbstractGangTask("G1 note end"), _g1h(g1h), _max_live_bytes(0), _freed_bytes(0), _cleanup_list(cleanup_list), _hrclaimer(n_workers) {
AbstractGangTask("G1 note end"), _g1h(g1h), }
_max_live_bytes(0), _freed_bytes(0), _cleanup_list(cleanup_list) { }
void work(uint worker_id) { void work(uint worker_id) {
double start = os::elapsedTime(); double start = os::elapsedTime();
@ -1943,9 +1920,7 @@ public:
G1NoteEndOfConcMarkClosure g1_note_end(_g1h, &local_cleanup_list, G1NoteEndOfConcMarkClosure g1_note_end(_g1h, &local_cleanup_list,
&hrrs_cleanup_task); &hrrs_cleanup_task);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
_g1h->heap_region_par_iterate_chunked(&g1_note_end, worker_id, _g1h->heap_region_par_iterate(&g1_note_end, worker_id, &_hrclaimer);
_g1h->workers()->active_workers(),
HeapRegion::NoteEndClaimValue);
} else { } else {
_g1h->heap_region_iterate(&g1_note_end); _g1h->heap_region_iterate(&g1_note_end);
} }
@ -1991,16 +1966,16 @@ protected:
G1RemSet* _g1rs; G1RemSet* _g1rs;
BitMap* _region_bm; BitMap* _region_bm;
BitMap* _card_bm; BitMap* _card_bm;
HeapRegionClaimer _hrclaimer;
public: public:
G1ParScrubRemSetTask(G1CollectedHeap* g1h, G1ParScrubRemSetTask(G1CollectedHeap* g1h, BitMap* region_bm, BitMap* card_bm, uint n_workers) :
BitMap* region_bm, BitMap* card_bm) : AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), _region_bm(region_bm), _card_bm(card_bm), _hrclaimer(n_workers) {
AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()), }
_region_bm(region_bm), _card_bm(card_bm) { }
void work(uint worker_id) { void work(uint worker_id) {
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
_g1rs->scrub_par(_region_bm, _card_bm, worker_id, _g1rs->scrub_par(_region_bm, _card_bm, worker_id, &_hrclaimer);
HeapRegion::ScrubRemSetClaimValue);
} else { } else {
_g1rs->scrub(_region_bm, _card_bm); _g1rs->scrub(_region_bm, _card_bm);
} }
@ -2043,9 +2018,6 @@ void ConcurrentMark::cleanup() {
G1ParFinalCountTask g1_par_count_task(g1h, &_region_bm, &_card_bm); G1ParFinalCountTask g1_par_count_task(g1h, &_region_bm, &_card_bm);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
assert(g1h->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
g1h->set_par_threads(); g1h->set_par_threads();
n_workers = g1h->n_par_threads(); n_workers = g1h->n_par_threads();
assert(g1h->n_par_threads() == n_workers, assert(g1h->n_par_threads() == n_workers,
@ -2053,9 +2025,6 @@ void ConcurrentMark::cleanup() {
g1h->workers()->run_task(&g1_par_count_task); g1h->workers()->run_task(&g1_par_count_task);
// Done with the parallel phase so reset to 0. // Done with the parallel phase so reset to 0.
g1h->set_par_threads(0); g1h->set_par_threads(0);
assert(g1h->check_heap_region_claim_values(HeapRegion::FinalCountClaimValue),
"sanity check");
} else { } else {
n_workers = 1; n_workers = 1;
g1_par_count_task.work(0); g1_par_count_task.work(0);
@ -2080,9 +2049,6 @@ void ConcurrentMark::cleanup() {
g1h->workers()->run_task(&g1_par_verify_task); g1h->workers()->run_task(&g1_par_verify_task);
// Done with the parallel phase so reset to 0. // Done with the parallel phase so reset to 0.
g1h->set_par_threads(0); g1h->set_par_threads(0);
assert(g1h->check_heap_region_claim_values(HeapRegion::VerifyCountClaimValue),
"sanity check");
} else { } else {
g1_par_verify_task.work(0); g1_par_verify_task.work(0);
} }
@ -2108,14 +2074,11 @@ void ConcurrentMark::cleanup() {
g1h->reset_gc_time_stamp(); g1h->reset_gc_time_stamp();
// Note end of marking in all heap regions. // Note end of marking in all heap regions.
G1ParNoteEndTask g1_par_note_end_task(g1h, &_cleanup_list); G1ParNoteEndTask g1_par_note_end_task(g1h, &_cleanup_list, n_workers);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
g1h->set_par_threads((int)n_workers); g1h->set_par_threads((int)n_workers);
g1h->workers()->run_task(&g1_par_note_end_task); g1h->workers()->run_task(&g1_par_note_end_task);
g1h->set_par_threads(0); g1h->set_par_threads(0);
assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue),
"sanity check");
} else { } else {
g1_par_note_end_task.work(0); g1_par_note_end_task.work(0);
} }
@ -2132,15 +2095,11 @@ void ConcurrentMark::cleanup() {
// regions. // regions.
if (G1ScrubRemSets) { if (G1ScrubRemSets) {
double rs_scrub_start = os::elapsedTime(); double rs_scrub_start = os::elapsedTime();
G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm); G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm, n_workers);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
g1h->set_par_threads((int)n_workers); g1h->set_par_threads((int)n_workers);
g1h->workers()->run_task(&g1_par_scrub_rs_task); g1h->workers()->run_task(&g1_par_scrub_rs_task);
g1h->set_par_threads(0); g1h->set_par_threads(0);
assert(g1h->check_heap_region_claim_values(
HeapRegion::ScrubRemSetClaimValue),
"sanity check");
} else { } else {
g1_par_scrub_rs_task.work(0); g1_par_scrub_rs_task.work(0);
} }
@ -3288,6 +3247,7 @@ protected:
BitMap* _cm_card_bm; BitMap* _cm_card_bm;
uint _max_worker_id; uint _max_worker_id;
int _active_workers; int _active_workers;
HeapRegionClaimer _hrclaimer;
public: public:
G1AggregateCountDataTask(G1CollectedHeap* g1h, G1AggregateCountDataTask(G1CollectedHeap* g1h,
@ -3295,18 +3255,18 @@ public:
BitMap* cm_card_bm, BitMap* cm_card_bm,
uint max_worker_id, uint max_worker_id,
int n_workers) : int n_workers) :
AbstractGangTask("Count Aggregation"), AbstractGangTask("Count Aggregation"),
_g1h(g1h), _cm(cm), _cm_card_bm(cm_card_bm), _g1h(g1h), _cm(cm), _cm_card_bm(cm_card_bm),
_max_worker_id(max_worker_id), _max_worker_id(max_worker_id),
_active_workers(n_workers) { } _active_workers(n_workers),
_hrclaimer(_active_workers) {
}
void work(uint worker_id) { void work(uint worker_id) {
AggregateCountDataHRClosure cl(_g1h, _cm_card_bm, _max_worker_id); AggregateCountDataHRClosure cl(_g1h, _cm_card_bm, _max_worker_id);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
_g1h->heap_region_par_iterate_chunked(&cl, worker_id, _g1h->heap_region_par_iterate(&cl, worker_id, &_hrclaimer);
_active_workers,
HeapRegion::AggregateCountClaimValue);
} else { } else {
_g1h->heap_region_iterate(&cl); _g1h->heap_region_iterate(&cl);
} }
@ -3323,15 +3283,9 @@ void ConcurrentMark::aggregate_count_data() {
_max_worker_id, n_workers); _max_worker_id, n_workers);
if (G1CollectedHeap::use_parallel_gc_threads()) { if (G1CollectedHeap::use_parallel_gc_threads()) {
assert(_g1h->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
_g1h->set_par_threads(n_workers); _g1h->set_par_threads(n_workers);
_g1h->workers()->run_task(&g1_par_agg_task); _g1h->workers()->run_task(&g1_par_agg_task);
_g1h->set_par_threads(0); _g1h->set_par_threads(0);
assert(_g1h->check_heap_region_claim_values(HeapRegion::AggregateCountClaimValue),
"sanity check");
_g1h->reset_heap_region_claim_values();
} else { } else {
g1_par_agg_task.work(0); g1_par_agg_task.work(0);
} }

186
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
View File

@ -90,8 +90,8 @@ size_t G1CollectedHeap::_humongous_object_threshold_in_words = 0;
// Notes on implementation of parallelism in different tasks. // Notes on implementation of parallelism in different tasks.
// //
// G1ParVerifyTask uses heap_region_par_iterate_chunked() for parallelism. // G1ParVerifyTask uses heap_region_par_iterate() for parallelism.
// The number of GC workers is passed to heap_region_par_iterate_chunked(). // The number of GC workers is passed to heap_region_par_iterate().
// It does use run_task() which sets _n_workers in the task. // It does use run_task() which sets _n_workers in the task.
// G1ParTask executes g1_process_roots() -> // G1ParTask executes g1_process_roots() ->
// SharedHeap::process_roots() which calls eventually to // SharedHeap::process_roots() which calls eventually to
@ -1215,17 +1215,15 @@ public:
class ParRebuildRSTask: public AbstractGangTask { class ParRebuildRSTask: public AbstractGangTask {
G1CollectedHeap* _g1; G1CollectedHeap* _g1;
HeapRegionClaimer _hrclaimer;
public: public:
ParRebuildRSTask(G1CollectedHeap* g1) ParRebuildRSTask(G1CollectedHeap* g1) :
: AbstractGangTask("ParRebuildRSTask"), AbstractGangTask("ParRebuildRSTask"), _g1(g1), _hrclaimer(g1->workers()->active_workers()) {}
_g1(g1)
{ }
void work(uint worker_id) { void work(uint worker_id) {
RebuildRSOutOfRegionClosure rebuild_rs(_g1, worker_id); RebuildRSOutOfRegionClosure rebuild_rs(_g1, worker_id);
_g1->heap_region_par_iterate_chunked(&rebuild_rs, worker_id, _g1->heap_region_par_iterate(&rebuild_rs, worker_id, &_hrclaimer);
_g1->workers()->active_workers(),
HeapRegion::RebuildRSClaimValue);
} }
}; };
@ -1455,8 +1453,6 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
set_par_threads(n_workers); set_par_threads(n_workers);
ParRebuildRSTask rebuild_rs_task(this); ParRebuildRSTask rebuild_rs_task(this);
assert(check_heap_region_claim_values(
HeapRegion::InitialClaimValue), "sanity check");
assert(UseDynamicNumberOfGCThreads || assert(UseDynamicNumberOfGCThreads ||
workers()->active_workers() == workers()->total_workers(), workers()->active_workers() == workers()->total_workers(),
"Unless dynamic should use total workers"); "Unless dynamic should use total workers");
@ -1466,9 +1462,6 @@ bool G1CollectedHeap::do_collection(bool explicit_gc,
set_par_threads(workers()->active_workers()); set_par_threads(workers()->active_workers());
workers()->run_task(&rebuild_rs_task); workers()->run_task(&rebuild_rs_task);
set_par_threads(0); set_par_threads(0);
assert(check_heap_region_claim_values(
HeapRegion::RebuildRSClaimValue), "sanity check");
reset_heap_region_claim_values();
} else { } else {
RebuildRSOutOfRegionClosure rebuild_rs(this); RebuildRSOutOfRegionClosure rebuild_rs(this);
heap_region_iterate(&rebuild_rs); heap_region_iterate(&rebuild_rs);
@ -2634,111 +2627,12 @@ void G1CollectedHeap::heap_region_iterate(HeapRegionClosure* cl) const {
} }
void void
G1CollectedHeap::heap_region_par_iterate_chunked(HeapRegionClosure* cl, G1CollectedHeap::heap_region_par_iterate(HeapRegionClosure* cl,
uint worker_id, uint worker_id,
uint num_workers, HeapRegionClaimer *hrclaimer) const {
jint claim_value) const { _hrm.par_iterate(cl, worker_id, hrclaimer);
_hrm.par_iterate(cl, worker_id, num_workers, claim_value);
} }
class ResetClaimValuesClosure: public HeapRegionClosure {
public:
bool doHeapRegion(HeapRegion* r) {
r->set_claim_value(HeapRegion::InitialClaimValue);
return false;
}
};
void G1CollectedHeap::reset_heap_region_claim_values() {
ResetClaimValuesClosure blk;
heap_region_iterate(&blk);
}
void G1CollectedHeap::reset_cset_heap_region_claim_values() {
ResetClaimValuesClosure blk;
collection_set_iterate(&blk);
}
#ifdef ASSERT
// This checks whether all regions in the heap have the correct claim
// value. I also piggy-backed on this a check to ensure that the
// humongous_start_region() information on "continues humongous"
// regions is correct.
class CheckClaimValuesClosure : public HeapRegionClosure {
private:
jint _claim_value;
uint _failures;
HeapRegion* _sh_region;
public:
CheckClaimValuesClosure(jint claim_value) :
_claim_value(claim_value), _failures(0), _sh_region(NULL) { }
bool doHeapRegion(HeapRegion* r) {
if (r->claim_value() != _claim_value) {
gclog_or_tty->print_cr("Region " HR_FORMAT ", "
"claim value = %d, should be %d",
HR_FORMAT_PARAMS(r),
r->claim_value(), _claim_value);
++_failures;
}
if (!r->is_humongous()) {
_sh_region = NULL;
} else if (r->is_starts_humongous()) {
_sh_region = r;
} else if (r->is_continues_humongous()) {
if (r->humongous_start_region() != _sh_region) {
gclog_or_tty->print_cr("Region " HR_FORMAT ", "
"HS = "PTR_FORMAT", should be "PTR_FORMAT,
HR_FORMAT_PARAMS(r),
r->humongous_start_region(),
_sh_region);
++_failures;
}
}
return false;
}
uint failures() { return _failures; }
};
bool G1CollectedHeap::check_heap_region_claim_values(jint claim_value) {
CheckClaimValuesClosure cl(claim_value);
heap_region_iterate(&cl);
return cl.failures() == 0;
}
class CheckClaimValuesInCSetHRClosure: public HeapRegionClosure {
private:
jint _claim_value;
uint _failures;
public:
CheckClaimValuesInCSetHRClosure(jint claim_value) :
_claim_value(claim_value), _failures(0) { }
uint failures() { return _failures; }
bool doHeapRegion(HeapRegion* hr) {
assert(hr->in_collection_set(), "how?");
assert(!hr->is_humongous(), "H-region in CSet");
if (hr->claim_value() != _claim_value) {
gclog_or_tty->print_cr("CSet Region " HR_FORMAT ", "
"claim value = %d, should be %d",
HR_FORMAT_PARAMS(hr),
hr->claim_value(), _claim_value);
_failures += 1;
}
return false;
}
};
bool G1CollectedHeap::check_cset_heap_region_claim_values(jint claim_value) {
CheckClaimValuesInCSetHRClosure cl(claim_value);
collection_set_iterate(&cl);
return cl.failures() == 0;
}
#endif // ASSERT
// Clear the cached CSet starting regions and (more importantly) // Clear the cached CSet starting regions and (more importantly)
// the time stamps. Called when we reset the GC time stamp. // the time stamps. Called when we reset the GC time stamp.
void G1CollectedHeap::clear_cset_start_regions() { void G1CollectedHeap::clear_cset_start_regions() {
@ -3252,19 +3146,21 @@ public:
class G1ParVerifyTask: public AbstractGangTask { class G1ParVerifyTask: public AbstractGangTask {
private: private:
G1CollectedHeap* _g1h; G1CollectedHeap* _g1h;
VerifyOption _vo; VerifyOption _vo;
bool _failures; bool _failures;
HeapRegionClaimer _hrclaimer;
public: public:
// _vo == UsePrevMarking -> use "prev" marking information, // _vo == UsePrevMarking -> use "prev" marking information,
// _vo == UseNextMarking -> use "next" marking information, // _vo == UseNextMarking -> use "next" marking information,
// _vo == UseMarkWord -> use mark word from object header. // _vo == UseMarkWord -> use mark word from object header.
G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) : G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) :
AbstractGangTask("Parallel verify task"), AbstractGangTask("Parallel verify task"),
_g1h(g1h), _g1h(g1h),
_vo(vo), _vo(vo),
_failures(false) { } _failures(false),
_hrclaimer(g1h->workers()->active_workers()) {}
bool failures() { bool failures() {
return _failures; return _failures;
@ -3273,9 +3169,7 @@ public:
void work(uint worker_id) { void work(uint worker_id) {
HandleMark hm; HandleMark hm;
VerifyRegionClosure blk(true, _vo); VerifyRegionClosure blk(true, _vo);
_g1h->heap_region_par_iterate_chunked(&blk, worker_id, _g1h->heap_region_par_iterate(&blk, worker_id, &_hrclaimer);
_g1h->workers()->active_workers(),
HeapRegion::ParVerifyClaimValue);
if (blk.failures()) { if (blk.failures()) {
_failures = true; _failures = true;
} }
@ -3317,8 +3211,6 @@ void G1CollectedHeap::verify(bool silent, VerifyOption vo) {
if (!silent) { gclog_or_tty->print("HeapRegions "); } if (!silent) { gclog_or_tty->print("HeapRegions "); }
if (GCParallelVerificationEnabled && ParallelGCThreads > 1) { if (GCParallelVerificationEnabled && ParallelGCThreads > 1) {
assert(check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
G1ParVerifyTask task(this, vo); G1ParVerifyTask task(this, vo);
assert(UseDynamicNumberOfGCThreads || assert(UseDynamicNumberOfGCThreads ||
@ -3332,15 +3224,6 @@ void G1CollectedHeap::verify(bool silent, VerifyOption vo) {
failures = true; failures = true;
} }
// Checks that the expected amount of parallel work was done.
// The implication is that n_workers is > 0.
assert(check_heap_region_claim_values(HeapRegion::ParVerifyClaimValue),
"sanity check");
reset_heap_region_claim_values();
assert(check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
} else { } else {
VerifyRegionClosure blk(false, vo); VerifyRegionClosure blk(false, vo);
heap_region_iterate(&blk); heap_region_iterate(&blk);
@ -3927,8 +3810,6 @@ G1CollectedHeap::do_collection_pause_at_safepoint(double target_pause_time_ms) {
} }
assert(check_young_list_well_formed(), "young list should be well formed"); assert(check_young_list_well_formed(), "young list should be well formed");
assert(check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
// Don't dynamically change the number of GC threads this early. A value of // Don't dynamically change the number of GC threads this early. A value of
// 0 is used to indicate serial work. When parallel work is done, // 0 is used to indicate serial work. When parallel work is done,
@ -4289,26 +4170,12 @@ void G1CollectedHeap::finalize_for_evac_failure() {
} }
void G1CollectedHeap::remove_self_forwarding_pointers() { void G1CollectedHeap::remove_self_forwarding_pointers() {
assert(check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
double remove_self_forwards_start = os::elapsedTime(); double remove_self_forwards_start = os::elapsedTime();
set_par_threads();
G1ParRemoveSelfForwardPtrsTask rsfp_task(this); G1ParRemoveSelfForwardPtrsTask rsfp_task(this);
workers()->run_task(&rsfp_task);
if (G1CollectedHeap::use_parallel_gc_threads()) { set_par_threads(0);
set_par_threads();
workers()->run_task(&rsfp_task);
set_par_threads(0);
} else {
rsfp_task.work(0);
}
assert(check_cset_heap_region_claim_values(HeapRegion::ParEvacFailureClaimValue), "sanity");
// Reset the claim values in the regions in the collection set.
reset_cset_heap_region_claim_values();
assert(check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
// Now restore saved marks, if any. // Now restore saved marks, if any.
assert(_objs_with_preserved_marks.size() == assert(_objs_with_preserved_marks.size() ==
@ -5949,11 +5816,6 @@ void G1CollectedHeap::evacuate_collection_set(EvacuationInfo& evacuation_info) {
purge_code_root_memory(); purge_code_root_memory();
if (g1_policy()->during_initial_mark_pause()) {
// Reset the claim values set during marking the strong code roots
reset_heap_region_claim_values();
}
finalize_for_evac_failure(); finalize_for_evac_failure();
if (evacuation_failed()) { if (evacuation_failed()) {

42
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp
View File

@ -211,6 +211,7 @@ class G1CollectedHeap : public SharedHeap {
friend class G1FreeHumongousRegionClosure; friend class G1FreeHumongousRegionClosure;
// Other related classes. // Other related classes.
friend class G1MarkSweep; friend class G1MarkSweep;
friend class HeapRegionClaimer;
private: private:
// The one and only G1CollectedHeap, so static functions can find it. // The one and only G1CollectedHeap, so static functions can find it.
@ -1377,38 +1378,15 @@ public:
inline HeapWord* bottom_addr_for_region(uint index) const; inline HeapWord* bottom_addr_for_region(uint index) const;
// Divide the heap region sequence into "chunks" of some size (the number // Iterate over the heap regions in parallel. Assumes that this will be called
// of regions divided by the number of parallel threads times some // in parallel by ParallelGCThreads worker threads with distinct worker ids
// overpartition factor, currently 4). Assumes that this will be called // in the range [0..max(ParallelGCThreads-1, 1)]. Applies "blk->doHeapRegion"
// in parallel by ParallelGCThreads worker threads with distinct worker // to each of the regions, by attempting to claim the region using the
// ids in the range [0..max(ParallelGCThreads-1, 1)], that all parallel // HeapRegionClaimer and, if successful, applying the closure to the claimed
// calls will use the same "claim_value", and that that claim value is // region.
// different from the claim_value of any heap region before the start of void heap_region_par_iterate(HeapRegionClosure* cl,
// the iteration. Applies "blk->doHeapRegion" to each of the regions, by uint worker_id,
// attempting to claim the first region in each chunk, and, if HeapRegionClaimer* hrclaimer) const;
// successful, applying the closure to each region in the chunk (and
// setting the claim value of the second and subsequent regions of the
// chunk.) For now requires that "doHeapRegion" always returns "false",
// i.e., that a closure never attempt to abort a traversal.
void heap_region_par_iterate_chunked(HeapRegionClosure* cl,
uint worker_id,
uint num_workers,
jint claim_value) const;
// It resets all the region claim values to the default.
void reset_heap_region_claim_values();
// Resets the claim values of regions in the current
// collection set to the default.
void reset_cset_heap_region_claim_values();
#ifdef ASSERT
bool check_heap_region_claim_values(jint claim_value);
// Same as the routine above but only checks regions in the
// current collection set.
bool check_cset_heap_region_claim_values(jint claim_value);
#endif // ASSERT
// Clear the cached cset start regions and (more importantly) // Clear the cached cset start regions and (more importantly)
// the time stamps. Called when we reset the GC time stamp. // the time stamps. Called when we reset the GC time stamp.

22
hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp
View File

@ -1598,19 +1598,17 @@ class ParKnownGarbageTask: public AbstractGangTask {
CollectionSetChooser* _hrSorted; CollectionSetChooser* _hrSorted;
uint _chunk_size; uint _chunk_size;
G1CollectedHeap* _g1; G1CollectedHeap* _g1;
HeapRegionClaimer _hrclaimer;
public: public:
ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size) : ParKnownGarbageTask(CollectionSetChooser* hrSorted, uint chunk_size, uint n_workers) :
AbstractGangTask("ParKnownGarbageTask"), AbstractGangTask("ParKnownGarbageTask"),
_hrSorted(hrSorted), _chunk_size(chunk_size), _hrSorted(hrSorted), _chunk_size(chunk_size),
_g1(G1CollectedHeap::heap()) { } _g1(G1CollectedHeap::heap()), _hrclaimer(n_workers) {}
void work(uint worker_id) { void work(uint worker_id) {
ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size); ParKnownGarbageHRClosure parKnownGarbageCl(_hrSorted, _chunk_size);
_g1->heap_region_par_iterate(&parKnownGarbageCl, worker_id, &_hrclaimer);
// Back to zero for the claim value.
_g1->heap_region_par_iterate_chunked(&parKnownGarbageCl, worker_id,
_g1->workers()->active_workers(),
HeapRegion::InitialClaimValue);
} }
}; };
@ -1641,12 +1639,8 @@ G1CollectorPolicy::record_concurrent_mark_cleanup_end(int no_of_gc_threads) {
} }
_collectionSetChooser->prepare_for_par_region_addition(_g1->num_regions(), _collectionSetChooser->prepare_for_par_region_addition(_g1->num_regions(),
WorkUnit); WorkUnit);
ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser, ParKnownGarbageTask parKnownGarbageTask(_collectionSetChooser, WorkUnit, (uint) no_of_gc_threads);
(int) WorkUnit);
_g1->workers()->run_task(&parKnownGarbageTask); _g1->workers()->run_task(&parKnownGarbageTask);
assert(_g1->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
"sanity check");
} else { } else {
KnownGarbageClosure knownGarbagecl(_collectionSetChooser); KnownGarbageClosure knownGarbagecl(_collectionSetChooser);
_g1->heap_region_iterate(&knownGarbagecl); _g1->heap_region_iterate(&knownGarbagecl);

19
hotspot/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp
View File

@ -177,16 +177,18 @@ class RemoveSelfForwardPtrHRClosure: public HeapRegionClosure {
G1CollectedHeap* _g1h; G1CollectedHeap* _g1h;
ConcurrentMark* _cm; ConcurrentMark* _cm;
uint _worker_id; uint _worker_id;
HeapRegionClaimer* _hrclaimer;
DirtyCardQueue _dcq; DirtyCardQueue _dcq;
UpdateRSetDeferred _update_rset_cl; UpdateRSetDeferred _update_rset_cl;
public: public:
RemoveSelfForwardPtrHRClosure(G1CollectedHeap* g1h, RemoveSelfForwardPtrHRClosure(G1CollectedHeap* g1h,
uint worker_id) : uint worker_id,
_g1h(g1h), _dcq(&g1h->dirty_card_queue_set()), _update_rset_cl(g1h, &_dcq), HeapRegionClaimer* hrclaimer) :
_worker_id(worker_id), _cm(_g1h->concurrent_mark()) { _g1h(g1h), _dcq(&g1h->dirty_card_queue_set()), _update_rset_cl(g1h, &_dcq),
} _worker_id(worker_id), _cm(_g1h->concurrent_mark()), _hrclaimer(hrclaimer) {
}
bool doHeapRegion(HeapRegion *hr) { bool doHeapRegion(HeapRegion *hr) {
bool during_initial_mark = _g1h->g1_policy()->during_initial_mark_pause(); bool during_initial_mark = _g1h->g1_policy()->during_initial_mark_pause();
@ -195,7 +197,7 @@ public:
assert(!hr->is_humongous(), "sanity"); assert(!hr->is_humongous(), "sanity");
assert(hr->in_collection_set(), "bad CS"); assert(hr->in_collection_set(), "bad CS");
if (hr->claimHeapRegion(HeapRegion::ParEvacFailureClaimValue)) { if (_hrclaimer->claim_region(hr->hrm_index())) {
if (hr->evacuation_failed()) { if (hr->evacuation_failed()) {
RemoveSelfForwardPtrObjClosure rspc(_g1h, _cm, hr, &_update_rset_cl, RemoveSelfForwardPtrObjClosure rspc(_g1h, _cm, hr, &_update_rset_cl,
during_initial_mark, during_initial_mark,
@ -233,14 +235,15 @@ public:
class G1ParRemoveSelfForwardPtrsTask: public AbstractGangTask { class G1ParRemoveSelfForwardPtrsTask: public AbstractGangTask {
protected: protected:
G1CollectedHeap* _g1h; G1CollectedHeap* _g1h;
HeapRegionClaimer _hrclaimer;
public: public:
G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) : G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) :
AbstractGangTask("G1 Remove Self-forwarding Pointers"), AbstractGangTask("G1 Remove Self-forwarding Pointers"), _g1h(g1h),
_g1h(g1h) { } _hrclaimer(g1h->workers()->active_workers()) {}
void work(uint worker_id) { void work(uint worker_id) {
RemoveSelfForwardPtrHRClosure rsfp_cl(_g1h, worker_id); RemoveSelfForwardPtrHRClosure rsfp_cl(_g1h, worker_id, &_hrclaimer);
HeapRegion* hr = _g1h->start_cset_region_for_worker(worker_id); HeapRegion* hr = _g1h->start_cset_region_for_worker(worker_id);
_g1h->collection_set_iterate_from(hr, &rsfp_cl); _g1h->collection_set_iterate_from(hr, &rsfp_cl);

8
hotspot/src/share/vm/gc_implementation/g1/g1RemSet.cpp
View File

@ -425,13 +425,9 @@ void G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
_g1->heap_region_iterate(&scrub_cl); _g1->heap_region_iterate(&scrub_cl);
} }
void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm, void G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer *hrclaimer) {
uint worker_num, int claim_val) {
ScrubRSClosure scrub_cl(region_bm, card_bm); ScrubRSClosure scrub_cl(region_bm, card_bm);
_g1->heap_region_par_iterate_chunked(&scrub_cl, _g1->heap_region_par_iterate(&scrub_cl, worker_num, hrclaimer);
worker_num,
n_workers(),
claim_val);
} }
G1TriggerClosure::G1TriggerClosure() : G1TriggerClosure::G1TriggerClosure() :

6
hotspot/src/share/vm/gc_implementation/g1/g1RemSet.hpp
View File

@ -128,10 +128,10 @@ public:
void scrub(BitMap* region_bm, BitMap* card_bm); void scrub(BitMap* region_bm, BitMap* card_bm);
// Like the above, but assumes is called in parallel: "worker_num" is the // Like the above, but assumes is called in parallel: "worker_num" is the
// parallel thread id of the current thread, and "claim_val" is the // parallel thread id of the current thread, and "hrclaimer" is the shared
// value that should be used to claim heap regions. // HeapRegionClaimer that should be used to claim heap regions.
void scrub_par(BitMap* region_bm, BitMap* card_bm, void scrub_par(BitMap* region_bm, BitMap* card_bm,
uint worker_num, int claim_val); uint worker_num, HeapRegionClaimer* hrclaimer);
// Refine the card corresponding to "card_ptr". // Refine the card corresponding to "card_ptr".
// If check_for_refs_into_cset is true, a true result is returned // If check_for_refs_into_cset is true, a true result is returned

14
hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp
View File

@ -217,7 +217,6 @@ void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
} else { } else {
hrrs->clear(); hrrs->clear();
} }
_claimed = InitialClaimValue;
} }
zero_marked_bytes(); zero_marked_bytes();
@ -294,17 +293,6 @@ void HeapRegion::clear_humongous() {
_humongous_start_region = NULL; _humongous_start_region = NULL;
} }
bool HeapRegion::claimHeapRegion(jint claimValue) {
jint current = _claimed;
if (current != claimValue) {
jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
if (res == current) {
return true;
}
}
return false;
}
HeapRegion::HeapRegion(uint hrm_index, HeapRegion::HeapRegion(uint hrm_index,
G1BlockOffsetSharedArray* sharedOffsetArray, G1BlockOffsetSharedArray* sharedOffsetArray,
MemRegion mr) : MemRegion mr) :
@ -314,7 +302,7 @@ HeapRegion::HeapRegion(uint hrm_index,
_humongous_start_region(NULL), _humongous_start_region(NULL),
_in_collection_set(false), _in_collection_set(false),
_next_in_special_set(NULL), _next_in_special_set(NULL),
_claimed(InitialClaimValue), _evacuation_failed(false), _evacuation_failed(false),
_prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0), _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
_next_young_region(NULL), _next_young_region(NULL),
_next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),

22
hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp
View File

@ -254,9 +254,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
HeapRegionSetBase* _containing_set; HeapRegionSetBase* _containing_set;
#endif // ASSERT #endif // ASSERT
// For parallel heapRegion traversal.
jint _claimed;
// We use concurrent marking to determine the amount of live data // We use concurrent marking to determine the amount of live data
// in each heap region. // in each heap region.
size_t _prev_marked_bytes; // Bytes known to be live via last completed marking. size_t _prev_marked_bytes; // Bytes known to be live via last completed marking.
@ -336,19 +333,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
// up once during initialization time. // up once during initialization time.
static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size); static void setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size);
enum ClaimValues {
InitialClaimValue = 0,
FinalCountClaimValue = 1,
NoteEndClaimValue = 2,
ScrubRemSetClaimValue = 3,
ParVerifyClaimValue = 4,
RebuildRSClaimValue = 5,
ParEvacFailureClaimValue = 6,
AggregateCountClaimValue = 7,
VerifyCountClaimValue = 8,
ParMarkRootClaimValue = 9
};
// All allocated blocks are occupied by objects in a HeapRegion // All allocated blocks are occupied by objects in a HeapRegion
bool block_is_obj(const HeapWord* p) const; bool block_is_obj(const HeapWord* p) const;
@ -691,12 +675,6 @@ class HeapRegion: public G1OffsetTableContigSpace {
return (HeapWord *) obj >= next_top_at_mark_start(); return (HeapWord *) obj >= next_top_at_mark_start();
} }
// For parallel heapRegion traversal.
bool claimHeapRegion(int claimValue);
jint claim_value() { return _claimed; }
// Use this carefully: only when you're sure no one is claiming...
void set_claim_value(int claimValue) { _claimed = claimValue; }
// Returns the "evacuation_failed" property of the region. // Returns the "evacuation_failed" property of the region.
bool evacuation_failed() { return _evacuation_failed; } bool evacuation_failed() { return _evacuation_failed; }

55
hotspot/src/share/vm/gc_implementation/g1/heapRegionManager.cpp
View File

@ -260,20 +260,17 @@ uint HeapRegionManager::find_unavailable_from_idx(uint start_idx, uint* res_idx)
return num_regions; return num_regions;
} }
uint HeapRegionManager::start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const { void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, HeapRegionClaimer* hrclaimer) const {
return num_regions * worker_i / num_workers; const uint start_index = hrclaimer->start_region_for_worker(worker_id);
}
void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, uint num_workers, jint claim_value) const {
const uint start_index = start_region_for_worker(worker_id, num_workers, _allocated_heapregions_length);
// Every worker will actually look at all regions, skipping over regions that // Every worker will actually look at all regions, skipping over regions that
// are currently not committed. // are currently not committed.
// This also (potentially) iterates over regions newly allocated during GC. This // This also (potentially) iterates over regions newly allocated during GC. This
// is no problem except for some extra work. // is no problem except for some extra work.
for (uint count = 0; count < _allocated_heapregions_length; count++) { const uint n_regions = hrclaimer->n_regions();
const uint index = (start_index + count) % _allocated_heapregions_length; for (uint count = 0; count < n_regions; count++) {
assert(0 <= index && index < _allocated_heapregions_length, "sanity"); const uint index = (start_index + count) % n_regions;
assert(0 <= index && index < n_regions, "sanity");
// Skip over unavailable regions // Skip over unavailable regions
if (!is_available(index)) { if (!is_available(index)) {
continue; continue;
@ -282,11 +279,11 @@ void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, uint
// We'll ignore "continues humongous" regions (we'll process them // We'll ignore "continues humongous" regions (we'll process them
// when we come across their corresponding "start humongous" // when we come across their corresponding "start humongous"
// region) and regions already claimed. // region) and regions already claimed.
if (r->claim_value() == claim_value || r->is_continues_humongous()) { if (hrclaimer->is_region_claimed(index) || r->is_continues_humongous()) {
continue; continue;
} }
// OK, try to claim it // OK, try to claim it
if (!r->claimHeapRegion(claim_value)) { if (!hrclaimer->claim_region(index)) {
continue; continue;
} }
// Success! // Success!
@ -306,13 +303,11 @@ void HeapRegionManager::par_iterate(HeapRegionClosure* blk, uint worker_id, uint
assert(chr->humongous_start_region() == r, assert(chr->humongous_start_region() == r,
err_msg("Must work on humongous continuation of the original start region " err_msg("Must work on humongous continuation of the original start region "
PTR_FORMAT ", but is " PTR_FORMAT, p2i(r), p2i(chr))); PTR_FORMAT ", but is " PTR_FORMAT, p2i(r), p2i(chr)));
assert(chr->claim_value() != claim_value, assert(!hrclaimer->is_region_claimed(ch_index),
"Must not have been claimed yet because claiming of humongous continuation first claims the start region"); "Must not have been claimed yet because claiming of humongous continuation first claims the start region");
bool claim_result = chr->claimHeapRegion(claim_value); // There's no need to actually claim the continues humongous region, but we can do it in an assert as an extra precaution.
// We should always be able to claim it; no one else should assert(hrclaimer->claim_region(ch_index), "We should always be able to claim the continuesHumongous part of the humongous object");
// be trying to claim this region.
guarantee(claim_result, "We should always be able to claim the is_continues_humongous part of the humongous object");
bool res2 = blk->doHeapRegion(chr); bool res2 = blk->doHeapRegion(chr);
if (res2) { if (res2) {
@ -445,3 +440,31 @@ void HeapRegionManager::verify_optional() {
} }
#endif // PRODUCT #endif // PRODUCT
HeapRegionClaimer::HeapRegionClaimer(uint n_workers) :
_n_workers(n_workers), _n_regions(G1CollectedHeap::heap()->_hrm._allocated_heapregions_length), _claims(NULL) {
assert(n_workers > 0, "Need at least one worker.");
_claims = NEW_C_HEAP_ARRAY(uint, _n_regions, mtGC);
memset(_claims, Unclaimed, sizeof(*_claims) * _n_regions);
}
HeapRegionClaimer::~HeapRegionClaimer() {
if (_claims != NULL) {
FREE_C_HEAP_ARRAY(uint, _claims, mtGC);
}
}
uint HeapRegionClaimer::start_region_for_worker(uint worker_id) const {
assert(worker_id < _n_workers, "Invalid worker_id.");
return _n_regions * worker_id / _n_workers;
}
bool HeapRegionClaimer::is_region_claimed(uint region_index) const {
assert(region_index < _n_regions, "Invalid index.");
return _claims[region_index] == Claimed;
}
bool HeapRegionClaimer::claim_region(uint region_index) {
assert(region_index < _n_regions, "Invalid index.");
uint old_val = Atomic::cmpxchg(Claimed, &_claims[region_index], Unclaimed);
return old_val == Unclaimed;
}

35
hotspot/src/share/vm/gc_implementation/g1/heapRegionManager.hpp
View File

@ -31,6 +31,7 @@
class HeapRegion; class HeapRegion;
class HeapRegionClosure; class HeapRegionClosure;
class HeapRegionClaimer;
class FreeRegionList; class FreeRegionList;
class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
@ -66,6 +67,7 @@ class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
class HeapRegionManager: public CHeapObj<mtGC> { class HeapRegionManager: public CHeapObj<mtGC> {
friend class VMStructs; friend class VMStructs;
friend class HeapRegionClaimer;
G1HeapRegionTable _regions; G1HeapRegionTable _regions;
@ -99,9 +101,6 @@ class HeapRegionManager: public CHeapObj<mtGC> {
// Notify other data structures about change in the heap layout. // Notify other data structures about change in the heap layout.
void update_committed_space(HeapWord* old_end, HeapWord* new_end); void update_committed_space(HeapWord* old_end, HeapWord* new_end);
// Calculate the starting region for each worker during parallel iteration so
// that they do not all start from the same region.
uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const;
// Find a contiguous set of empty or uncommitted regions of length num and return // Find a contiguous set of empty or uncommitted regions of length num and return
// the index of the first region or G1_NO_HRM_INDEX if the search was unsuccessful. // the index of the first region or G1_NO_HRM_INDEX if the search was unsuccessful.
@ -223,7 +222,7 @@ public:
// terminating the iteration early if doHeapRegion() returns true. // terminating the iteration early if doHeapRegion() returns true.
void iterate(HeapRegionClosure* blk) const; void iterate(HeapRegionClosure* blk) const;
void par_iterate(HeapRegionClosure* blk, uint worker_id, uint no_of_par_workers, jint claim_value) const; void par_iterate(HeapRegionClosure* blk, uint worker_id, HeapRegionClaimer* hrclaimer) const;
// Uncommit up to num_regions_to_remove regions that are completely free. // Uncommit up to num_regions_to_remove regions that are completely free.
// Return the actual number of uncommitted regions. // Return the actual number of uncommitted regions.
@ -235,5 +234,33 @@ public:
void verify_optional() PRODUCT_RETURN; void verify_optional() PRODUCT_RETURN;
}; };
// The HeapRegionClaimer is used during parallel iteration over heap regions,
// allowing workers to claim heap regions, gaining exclusive rights to these regions.
class HeapRegionClaimer : public StackObj {
uint _n_workers;
uint _n_regions;
uint* _claims;
static const uint Unclaimed = 0;
static const uint Claimed = 1;
public:
HeapRegionClaimer(uint n_workers);
~HeapRegionClaimer();
inline uint n_regions() const {
return _n_regions;
}
// Calculate the starting region for given worker so
// that they do not all start from the same region.
uint start_region_for_worker(uint worker_id) const;
// Check if region has been claimed with this HRClaimer.
bool is_region_claimed(uint region_index) const;
// Claim the given region, returns true if successfully claimed.
bool claim_region(uint region_index);
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP