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src/hotspot/share/gc/g1/g1CollectionSet.cpp
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rev 54087 : imported patch 8218668-reorganize-collection-set
@@ -57,13 +57,11 @@
_survivor_region_length(0),
_old_region_length(0),
_collection_set_regions(NULL),
_collection_set_cur_length(0),
_collection_set_max_length(0),
- _optional_regions(NULL),
- _optional_region_length(0),
- _optional_region_max_length(0),
+ _num_optional_regions(0),
_bytes_used_before(0),
_recorded_rs_lengths(0),
_inc_build_state(Inactive),
_inc_bytes_used_before(0),
_inc_recorded_rs_lengths(0),
@@ -89,34 +87,21 @@
assert((size_t) young_region_length() == _collection_set_cur_length,
"Young region length %u should match collection set length " SIZE_FORMAT, young_region_length(), _collection_set_cur_length);
_old_region_length = 0;
- _optional_region_length = 0;
+ _num_optional_regions = 0;
}
void G1CollectionSet::initialize(uint max_region_length) {
guarantee(_collection_set_regions == NULL, "Must only initialize once.");
_collection_set_max_length = max_region_length;
_collection_set_regions = NEW_C_HEAP_ARRAY(uint, max_region_length, mtGC);
}
-void G1CollectionSet::initialize_optional(uint max_length) {
- assert(_optional_regions == NULL, "Already initialized");
- assert(_optional_region_length == 0, "Already initialized");
- assert(_optional_region_max_length == 0, "Already initialized");
- _optional_region_max_length = max_length;
- _optional_regions = NEW_C_HEAP_ARRAY(HeapRegion*, _optional_region_max_length, mtGC);
-}
-
void G1CollectionSet::free_optional_regions() {
- _optional_region_length = 0;
- _optional_region_max_length = 0;
- if (_optional_regions != NULL) {
- FREE_C_HEAP_ARRAY(HeapRegion*, _optional_regions);
- _optional_regions = NULL;
- }
+ _num_optional_regions = 0;
}
void G1CollectionSet::clear_candidates() {
delete _candidates;
_candidates = NULL;
@@ -128,57 +113,51 @@
// Add the heap region at the head of the non-incremental collection set
void G1CollectionSet::add_old_region(HeapRegion* hr) {
assert_at_safepoint_on_vm_thread();
- assert(_inc_build_state == Active || hr->index_in_opt_cset() != G1OptionalCSet::InvalidCSetIndex,
+ assert(_inc_build_state == Active,
"Precondition, actively building cset or adding optional later on");
assert(hr->is_old(), "the region should be old");
- assert(!hr->in_collection_set(), "should not already be in the CSet");
+ assert(!hr->in_collection_set(), "should not already be in the collection set");
_g1h->register_old_region_with_cset(hr);
_collection_set_regions[_collection_set_cur_length++] = hr->hrm_index();
assert(_collection_set_cur_length <= _collection_set_max_length, "Collection set now larger than maximum size.");
_bytes_used_before += hr->used();
- size_t rs_length = hr->rem_set()->occupied();
- _recorded_rs_lengths += rs_length;
- _old_region_length += 1;
+ _recorded_rs_lengths += hr->rem_set()->occupied();
+ _old_region_length++;
- log_trace(gc, cset)("Added old region %d to collection set", hr->hrm_index());
+ _g1h->old_set_remove(hr);
}
void G1CollectionSet::add_optional_region(HeapRegion* hr) {
- assert(!optional_is_full(), "Precondition, must have room left for this region");
assert(hr->is_old(), "the region should be old");
assert(!hr->in_collection_set(), "should not already be in the CSet");
_g1h->register_optional_region_with_cset(hr);
- _optional_regions[_optional_region_length] = hr;
- uint index = _optional_region_length++;
- hr->set_index_in_opt_cset(index);
-
- log_trace(gc, cset)("Added region %d to optional collection set (%u)", hr->hrm_index(), _optional_region_length);
+ hr->set_index_in_opt_cset(_num_optional_regions++);
}
-// Initialize the per-collection-set information
void G1CollectionSet::start_incremental_building() {
assert(_collection_set_cur_length == 0, "Collection set must be empty before starting a new collection set.");
assert(_inc_build_state == Inactive, "Precondition");
_inc_bytes_used_before = 0;
_inc_recorded_rs_lengths = 0;
_inc_recorded_rs_lengths_diffs = 0;
_inc_predicted_elapsed_time_ms = 0.0;
_inc_predicted_elapsed_time_ms_diffs = 0.0;
- _inc_build_state = Active;
+
+ update_incremental_marker();
}
-void G1CollectionSet::finalize_incremental_building() {
+void G1CollectionSet::finalize_young_increment() {
assert(_inc_build_state == Active, "Precondition");
assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
// The two "main" fields, _inc_recorded_rs_lengths and
// _inc_predicted_elapsed_time_ms, are updated by the thread
@@ -209,33 +188,52 @@
}
void G1CollectionSet::clear() {
assert_at_safepoint_on_vm_thread();
_collection_set_cur_length = 0;
- _optional_region_length = 0;
}
void G1CollectionSet::iterate(HeapRegionClosure* cl) const {
- iterate_from(cl, 0, 1);
-}
-
-void G1CollectionSet::iterate_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const {
size_t len = _collection_set_cur_length;
OrderAccess::loadload();
+
+ for (uint i = 0; i < len; i++) {
+ HeapRegion* r = _g1h->region_at(_collection_set_regions[i]);
+ bool result = cl->do_heap_region(r);
+ if (result) {
+ cl->set_incomplete();
+ return;
+ }
+ }
+}
+
+void G1CollectionSet::iterate_optional(HeapRegionClosure* cl) const {
+ assert_at_safepoint();
+
+ for (uint i = 0; i < _num_optional_regions; i++) {
+ HeapRegion* r = _candidates->at(i);
+ bool result = cl->do_heap_region(r);
+ guarantee(!result, "Must not cancel iteration");
+ }
+}
+
+void G1CollectionSet::iterate_incremental_part_from(HeapRegionClosure* cl, uint worker_id, uint total_workers) const {
+ assert_at_safepoint();
+
+ size_t len = _collection_set_cur_length - _inc_part_start;
if (len == 0) {
return;
}
+
size_t start_pos = (worker_id * len) / total_workers;
size_t cur_pos = start_pos;
do {
- HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos]);
+ HeapRegion* r = _g1h->region_at(_collection_set_regions[cur_pos + _inc_part_start]);
bool result = cl->do_heap_region(r);
- if (result) {
- cl->set_incomplete();
- return;
- }
+ guarantee(!result, "Must not cancel iteration");
+
cur_pos++;
if (cur_pos == len) {
cur_pos = 0;
}
} while (cur_pos != start_pos);
@@ -397,11 +395,11 @@
#endif // !PRODUCT
double G1CollectionSet::finalize_young_part(double target_pause_time_ms, G1SurvivorRegions* survivors) {
double young_start_time_sec = os::elapsedTime();
- finalize_incremental_building();
+ finalize_young_increment();
guarantee(target_pause_time_ms > 0.0,
"target_pause_time_ms = %1.6lf should be positive", target_pause_time_ms);
size_t pending_cards = _policy->pending_cards();
@@ -438,34 +436,10 @@
phase_times()->record_young_cset_choice_time_ms((young_end_time_sec - young_start_time_sec) * 1000.0);
return time_remaining_ms;
}
-void G1CollectionSet::add_as_old(HeapRegion* hr) {
- candidates()->pop_front(); // already have region via peek()
- _g1h->old_set_remove(hr);
- add_old_region(hr);
-}
-
-void G1CollectionSet::add_as_optional(HeapRegion* hr) {
- assert(_optional_regions != NULL, "Must not be called before array is allocated");
- candidates()->pop_front(); // already have region via peek()
- _g1h->old_set_remove(hr);
- add_optional_region(hr);
-}
-
-bool G1CollectionSet::optional_is_full() {
- assert(_optional_region_length <= _optional_region_max_length, "Invariant");
- return _optional_region_length == _optional_region_max_length;
-}
-
-void G1CollectionSet::clear_optional_region(const HeapRegion* hr) {
- assert(_optional_regions != NULL, "Must not be called before array is allocated");
- uint index = hr->index_in_opt_cset();
- _optional_regions[index] = NULL;
-}
-
static int compare_region_idx(const uint a, const uint b) {
if (a > b) {
return 1;
} else if (a == b) {
return 0;
@@ -474,191 +448,92 @@
}
}
void G1CollectionSet::finalize_old_part(double time_remaining_ms) {
double non_young_start_time_sec = os::elapsedTime();
- double predicted_old_time_ms = 0.0;
- double predicted_optional_time_ms = 0.0;
- double optional_threshold_ms = time_remaining_ms * _policy->optional_prediction_fraction();
- uint expensive_region_num = 0;
+
+ uint num_expensive_regions = 0;
if (collector_state()->in_mixed_phase()) {
candidates()->verify();
- const uint min_old_cset_length = _policy->calc_min_old_cset_length();
- const uint max_old_cset_length = MAX2(min_old_cset_length, _policy->calc_max_old_cset_length());
- bool check_time_remaining = _policy->adaptive_young_list_length();
-
- initialize_optional(max_old_cset_length - min_old_cset_length);
- log_debug(gc, ergo, cset)("Start adding old regions for mixed gc. min %u regions, max %u regions, "
- "time remaining %1.2fms, optional threshold %1.2fms",
- min_old_cset_length, max_old_cset_length, time_remaining_ms, optional_threshold_ms);
-
- HeapRegion* hr = candidates()->peek_front();
- while (hr != NULL) {
- if (old_region_length() + optional_region_length() >= max_old_cset_length) {
- // Added maximum number of old regions to the CSet.
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached max). "
- "old %u regions, optional %u regions",
- old_region_length(), optional_region_length());
- break;
- }
-
- // Stop adding regions if the remaining reclaimable space is
- // not above G1HeapWastePercent.
- size_t reclaimable_bytes = candidates()->remaining_reclaimable_bytes();
- double reclaimable_percent = _policy->reclaimable_bytes_percent(reclaimable_bytes);
- double threshold = (double) G1HeapWastePercent;
- if (reclaimable_percent <= threshold) {
- // We've added enough old regions that the amount of uncollected
- // reclaimable space is at or below the waste threshold. Stop
- // adding old regions to the CSet.
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (reclaimable percentage not over threshold). "
- "reclaimable: " SIZE_FORMAT "%s (%1.2f%%) threshold: " UINTX_FORMAT "%%",
- byte_size_in_proper_unit(reclaimable_bytes), proper_unit_for_byte_size(reclaimable_bytes),
- reclaimable_percent, G1HeapWastePercent);
- break;
- }
-
- double predicted_time_ms = predict_region_elapsed_time_ms(hr);
- time_remaining_ms = MAX2(time_remaining_ms - predicted_time_ms, 0.0);
- // Add regions to old set until we reach minimum amount
- if (old_region_length() < min_old_cset_length) {
- predicted_old_time_ms += predicted_time_ms;
- add_as_old(hr);
- // Record the number of regions added when no time remaining
- if (time_remaining_ms == 0.0) {
- expensive_region_num++;
- }
- } else {
- // In the non-auto-tuning case, we'll finish adding regions
- // to the CSet if we reach the minimum.
- if (!check_time_remaining) {
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (old CSet region num reached min).");
- break;
- }
- // Keep adding regions to old set until we reach optional threshold
- if (time_remaining_ms > optional_threshold_ms) {
- predicted_old_time_ms += predicted_time_ms;
- add_as_old(hr);
- } else if (time_remaining_ms > 0) {
- // Keep adding optional regions until time is up
- if (!optional_is_full()) {
- predicted_optional_time_ms += predicted_time_ms;
- add_as_optional(hr);
- } else {
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (optional set full).");
- break;
- }
- } else {
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (predicted time is too high).");
- break;
- }
- }
- hr = candidates()->peek_front();
- }
- if (hr == NULL) {
- log_debug(gc, ergo, cset)("Finish adding old regions to CSet (candidate old regions not available)");
+
+ uint num_initial_regions;
+ uint num_optional_regions;
+
+ _policy->select_old_collection_set_regions(candidates(),
+ time_remaining_ms,
+ num_expensive_regions,
+ num_initial_regions,
+ num_optional_regions);
+
+ // Prepare initial old regions.
+ move_candidates_to_collection_set(num_initial_regions);
+
+ // Prepare optional regions for evacuation.
+ uint candidate_idx = candidates()->cur_idx();
+ for (uint i = 0; i < num_optional_regions; i++) {
+ add_optional_region(candidates()->at(candidate_idx + i));
}
candidates()->verify();
}
stop_incremental_building();
- log_debug(gc, ergo, cset)("Finish choosing CSet regions old: %u, optional: %u, "
- "predicted old time: %1.2fms, predicted optional time: %1.2fms, time remaining: %1.2f",
- old_region_length(), optional_region_length(),
- predicted_old_time_ms, predicted_optional_time_ms, time_remaining_ms);
- if (expensive_region_num > 0) {
- log_debug(gc, ergo, cset)("CSet contains %u old regions that were added although the predicted time was too high.",
- expensive_region_num);
- }
-
double non_young_end_time_sec = os::elapsedTime();
phase_times()->record_non_young_cset_choice_time_ms((non_young_end_time_sec - non_young_start_time_sec) * 1000.0);
QuickSort::sort(_collection_set_regions, _collection_set_cur_length, compare_region_idx, true);
}
-HeapRegion* G1OptionalCSet::region_at(uint index) {
- return _cset->optional_region_at(index);
-}
-
-void G1OptionalCSet::prepare_evacuation(double time_limit) {
- assert(_current_index == _current_limit, "Before prepare no regions should be ready for evac");
-
- uint prepared_regions = 0;
- double prediction_ms = 0;
-
- _prepare_failed = true;
- for (uint i = _current_index; i < _cset->optional_region_length(); i++) {
- HeapRegion* hr = region_at(i);
- prediction_ms += _cset->predict_region_elapsed_time_ms(hr);
- if (prediction_ms > time_limit) {
- log_debug(gc, cset)("Prepared %u regions for optional evacuation. Predicted time: %.3fms", prepared_regions, prediction_ms);
+void G1CollectionSet::move_candidates_to_collection_set(uint num_old_candidate_regions) {
+ if (num_old_candidate_regions == 0) {
return;
}
-
- // This region will be included in the next optional evacuation.
- prepare_to_evacuate_optional_region(hr);
- prepared_regions++;
- _current_limit++;
- _prepare_failed = false;
+ uint candidate_idx = candidates()->cur_idx();
+ for (uint i = 0; i < num_old_candidate_regions; i++) {
+ HeapRegion* r = candidates()->at(candidate_idx + i);
+ // This potentially optional candidate region is going to be an actual collection
+ // set region. Clear cset marker.
+ _g1h->clear_in_cset(r);
+ add_old_region(r);
}
+ candidates()->remove(num_old_candidate_regions);
- log_debug(gc, cset)("Prepared all %u regions for optional evacuation. Predicted time: %.3fms",
- prepared_regions, prediction_ms);
+ candidates()->verify();
}
-bool G1OptionalCSet::prepare_failed() {
- return _prepare_failed;
+void G1CollectionSet::finalize_initial_collection_set(double target_pause_time_ms, G1SurvivorRegions* survivor) {
+ double time_remaining_ms = finalize_young_part(target_pause_time_ms, survivor);
+ finalize_old_part(time_remaining_ms);
}
-void G1OptionalCSet::complete_evacuation() {
- _evacuation_failed = false;
- for (uint i = _current_index; i < _current_limit; i++) {
- HeapRegion* hr = region_at(i);
- _cset->clear_optional_region(hr);
- if (hr->evacuation_failed()){
- _evacuation_failed = true;
- }
- }
- _current_index = _current_limit;
-}
+bool G1CollectionSet::finalize_optional_for_evacuation(double remaining_pause_time) {
+ update_incremental_marker();
-bool G1OptionalCSet::evacuation_failed() {
- return _evacuation_failed;
-}
+ uint num_selected_regions;
+ _policy->select_optional_collection_set_regions(candidates(),
+ _num_optional_regions,
+ remaining_pause_time,
+ num_selected_regions);
-G1OptionalCSet::~G1OptionalCSet() {
- G1CollectedHeap* g1h = G1CollectedHeap::heap();
- while (!is_empty()) {
- // We want to return regions not evacuated to the collection set candidates
- // in reverse order to maintain the old order.
- HeapRegion* hr = _cset->remove_last_optional_region();
- assert(hr != NULL, "Should be valid region left");
- _pset->record_unused_optional_region(hr);
- g1h->old_set_add(hr);
- g1h->clear_in_cset(hr);
- hr->set_index_in_opt_cset(InvalidCSetIndex);
- _cset->candidates()->push_front(hr);
- }
- _cset->free_optional_regions();
-}
+ move_candidates_to_collection_set(num_selected_regions);
-uint G1OptionalCSet::size() {
- return _cset->optional_region_length() - _current_index;
-}
+ _num_optional_regions -= num_selected_regions;
-bool G1OptionalCSet::is_empty() {
- return size() == 0;
+ stop_incremental_building();
+ return num_selected_regions > 0;
}
-void G1OptionalCSet::prepare_to_evacuate_optional_region(HeapRegion* hr) {
- log_trace(gc, cset)("Adding region %u for optional evacuation", hr->hrm_index());
- G1CollectedHeap::heap()->clear_in_cset(hr);
- _cset->add_old_region(hr);
+void G1CollectionSet::abandon_optional_collection_set(G1ParScanThreadStateSet* pss) {
+ for (uint i = 0; i < _num_optional_regions; i++) {
+ HeapRegion* r = candidates()->at(candidates()->cur_idx() + i);
+ pss->record_unused_optional_region(r);
+ _g1h->clear_in_cset(r);
+ r->clear_index_in_opt_cset();
+ }
+ _num_optional_regions = 0;
}
#ifdef ASSERT
class G1VerifyYoungCSetIndicesClosure : public HeapRegionClosure {
private:
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