--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/g1/g1CollectedHeap.cpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,6575 @@
+/*
+ * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "classfile/metadataOnStackMark.hpp"
+#include "classfile/stringTable.hpp"
+#include "code/codeCache.hpp"
+#include "code/icBuffer.hpp"
+#include "gc/g1/bufferingOopClosure.hpp"
+#include "gc/g1/concurrentG1Refine.hpp"
+#include "gc/g1/concurrentG1RefineThread.hpp"
+#include "gc/g1/concurrentMarkThread.inline.hpp"
+#include "gc/g1/g1AllocRegion.inline.hpp"
+#include "gc/g1/g1CollectedHeap.inline.hpp"
+#include "gc/g1/g1CollectorPolicy.hpp"
+#include "gc/g1/g1ErgoVerbose.hpp"
+#include "gc/g1/g1EvacFailure.hpp"
+#include "gc/g1/g1GCPhaseTimes.hpp"
+#include "gc/g1/g1Log.hpp"
+#include "gc/g1/g1MarkSweep.hpp"
+#include "gc/g1/g1OopClosures.inline.hpp"
+#include "gc/g1/g1ParScanThreadState.inline.hpp"
+#include "gc/g1/g1RegionToSpaceMapper.hpp"
+#include "gc/g1/g1RemSet.inline.hpp"
+#include "gc/g1/g1RootProcessor.hpp"
+#include "gc/g1/g1StringDedup.hpp"
+#include "gc/g1/g1YCTypes.hpp"
+#include "gc/g1/heapRegion.inline.hpp"
+#include "gc/g1/heapRegionRemSet.hpp"
+#include "gc/g1/heapRegionSet.inline.hpp"
+#include "gc/g1/vm_operations_g1.hpp"
+#include "gc/shared/gcHeapSummary.hpp"
+#include "gc/shared/gcLocker.inline.hpp"
+#include "gc/shared/gcTimer.hpp"
+#include "gc/shared/gcTrace.hpp"
+#include "gc/shared/gcTraceTime.hpp"
+#include "gc/shared/generationSpec.hpp"
+#include "gc/shared/isGCActiveMark.hpp"
+#include "gc/shared/referenceProcessor.hpp"
+#include "gc/shared/taskqueue.inline.hpp"
+#include "memory/allocation.hpp"
+#include "memory/iterator.hpp"
+#include "oops/oop.inline.hpp"
+#include "runtime/atomic.inline.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "runtime/vmThread.hpp"
+#include "utilities/globalDefinitions.hpp"
+#include "utilities/stack.inline.hpp"
+
+size_t G1CollectedHeap::_humongous_object_threshold_in_words = 0;
+
+// turn it on so that the contents of the young list (scan-only /
+// to-be-collected) are printed at "strategic" points before / during
+// / after the collection --- this is useful for debugging
+#define YOUNG_LIST_VERBOSE 0
+// CURRENT STATUS
+// This file is under construction. Search for "FIXME".
+
+// INVARIANTS/NOTES
+//
+// All allocation activity covered by the G1CollectedHeap interface is
+// serialized by acquiring the HeapLock. This happens in mem_allocate
+// and allocate_new_tlab, which are the "entry" points to the
+// allocation code from the rest of the JVM. (Note that this does not
+// apply to TLAB allocation, which is not part of this interface: it
+// is done by clients of this interface.)
+
+// Local to this file.
+
+class RefineCardTableEntryClosure: public CardTableEntryClosure {
+ bool _concurrent;
+public:
+ RefineCardTableEntryClosure() : _concurrent(true) { }
+
+ bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
+ bool oops_into_cset = G1CollectedHeap::heap()->g1_rem_set()->refine_card(card_ptr, worker_i, false);
+ // This path is executed by the concurrent refine or mutator threads,
+ // concurrently, and so we do not care if card_ptr contains references
+ // that point into the collection set.
+ assert(!oops_into_cset, "should be");
+
+ if (_concurrent && SuspendibleThreadSet::should_yield()) {
+ // Caller will actually yield.
+ return false;
+ }
+ // Otherwise, we finished successfully; return true.
+ return true;
+ }
+
+ void set_concurrent(bool b) { _concurrent = b; }
+};
+
+
+class RedirtyLoggedCardTableEntryClosure : public CardTableEntryClosure {
+ private:
+ size_t _num_processed;
+
+ public:
+ RedirtyLoggedCardTableEntryClosure() : CardTableEntryClosure(), _num_processed(0) { }
+
+ bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
+ *card_ptr = CardTableModRefBS::dirty_card_val();
+ _num_processed++;
+ return true;
+ }
+
+ size_t num_processed() const { return _num_processed; }
+};
+
+YoungList::YoungList(G1CollectedHeap* g1h) :
+ _g1h(g1h), _head(NULL), _length(0), _last_sampled_rs_lengths(0),
+ _survivor_head(NULL), _survivor_tail(NULL), _survivor_length(0) {
+ guarantee(check_list_empty(false), "just making sure...");
+}
+
+void YoungList::push_region(HeapRegion *hr) {
+ assert(!hr->is_young(), "should not already be young");
+ assert(hr->get_next_young_region() == NULL, "cause it should!");
+
+ hr->set_next_young_region(_head);
+ _head = hr;
+
+ _g1h->g1_policy()->set_region_eden(hr, (int) _length);
+ ++_length;
+}
+
+void YoungList::add_survivor_region(HeapRegion* hr) {
+ assert(hr->is_survivor(), "should be flagged as survivor region");
+ assert(hr->get_next_young_region() == NULL, "cause it should!");
+
+ hr->set_next_young_region(_survivor_head);
+ if (_survivor_head == NULL) {
+ _survivor_tail = hr;
+ }
+ _survivor_head = hr;
+ ++_survivor_length;
+}
+
+void YoungList::empty_list(HeapRegion* list) {
+ while (list != NULL) {
+ HeapRegion* next = list->get_next_young_region();
+ list->set_next_young_region(NULL);
+ list->uninstall_surv_rate_group();
+ // This is called before a Full GC and all the non-empty /
+ // non-humongous regions at the end of the Full GC will end up as
+ // old anyway.
+ list->set_old();
+ list = next;
+ }
+}
+
+void YoungList::empty_list() {
+ assert(check_list_well_formed(), "young list should be well formed");
+
+ empty_list(_head);
+ _head = NULL;
+ _length = 0;
+
+ empty_list(_survivor_head);
+ _survivor_head = NULL;
+ _survivor_tail = NULL;
+ _survivor_length = 0;
+
+ _last_sampled_rs_lengths = 0;
+
+ assert(check_list_empty(false), "just making sure...");
+}
+
+bool YoungList::check_list_well_formed() {
+ bool ret = true;
+
+ uint length = 0;
+ HeapRegion* curr = _head;
+ HeapRegion* last = NULL;
+ while (curr != NULL) {
+ if (!curr->is_young()) {
+ gclog_or_tty->print_cr("### YOUNG REGION "PTR_FORMAT"-"PTR_FORMAT" "
+ "incorrectly tagged (y: %d, surv: %d)",
+ p2i(curr->bottom()), p2i(curr->end()),
+ curr->is_young(), curr->is_survivor());
+ ret = false;
+ }
+ ++length;
+ last = curr;
+ curr = curr->get_next_young_region();
+ }
+ ret = ret && (length == _length);
+
+ if (!ret) {
+ gclog_or_tty->print_cr("### YOUNG LIST seems not well formed!");
+ gclog_or_tty->print_cr("### list has %u entries, _length is %u",
+ length, _length);
+ }
+
+ return ret;
+}
+
+bool YoungList::check_list_empty(bool check_sample) {
+ bool ret = true;
+
+ if (_length != 0) {
+ gclog_or_tty->print_cr("### YOUNG LIST should have 0 length, not %u",
+ _length);
+ ret = false;
+ }
+ if (check_sample && _last_sampled_rs_lengths != 0) {
+ gclog_or_tty->print_cr("### YOUNG LIST has non-zero last sampled RS lengths");
+ ret = false;
+ }
+ if (_head != NULL) {
+ gclog_or_tty->print_cr("### YOUNG LIST does not have a NULL head");
+ ret = false;
+ }
+ if (!ret) {
+ gclog_or_tty->print_cr("### YOUNG LIST does not seem empty");
+ }
+
+ return ret;
+}
+
+void
+YoungList::rs_length_sampling_init() {
+ _sampled_rs_lengths = 0;
+ _curr = _head;
+}
+
+bool
+YoungList::rs_length_sampling_more() {
+ return _curr != NULL;
+}
+
+void
+YoungList::rs_length_sampling_next() {
+ assert( _curr != NULL, "invariant" );
+ size_t rs_length = _curr->rem_set()->occupied();
+
+ _sampled_rs_lengths += rs_length;
+
+ // The current region may not yet have been added to the
+ // incremental collection set (it gets added when it is
+ // retired as the current allocation region).
+ if (_curr->in_collection_set()) {
+ // Update the collection set policy information for this region
+ _g1h->g1_policy()->update_incremental_cset_info(_curr, rs_length);
+ }
+
+ _curr = _curr->get_next_young_region();
+ if (_curr == NULL) {
+ _last_sampled_rs_lengths = _sampled_rs_lengths;
+ // gclog_or_tty->print_cr("last sampled RS lengths = %d", _last_sampled_rs_lengths);
+ }
+}
+
+void
+YoungList::reset_auxilary_lists() {
+ guarantee( is_empty(), "young list should be empty" );
+ assert(check_list_well_formed(), "young list should be well formed");
+
+ // Add survivor regions to SurvRateGroup.
+ _g1h->g1_policy()->note_start_adding_survivor_regions();
+ _g1h->g1_policy()->finished_recalculating_age_indexes(true /* is_survivors */);
+
+ int young_index_in_cset = 0;
+ for (HeapRegion* curr = _survivor_head;
+ curr != NULL;
+ curr = curr->get_next_young_region()) {
+ _g1h->g1_policy()->set_region_survivor(curr, young_index_in_cset);
+
+ // The region is a non-empty survivor so let's add it to
+ // the incremental collection set for the next evacuation
+ // pause.
+ _g1h->g1_policy()->add_region_to_incremental_cset_rhs(curr);
+ young_index_in_cset += 1;
+ }
+ assert((uint) young_index_in_cset == _survivor_length, "post-condition");
+ _g1h->g1_policy()->note_stop_adding_survivor_regions();
+
+ _head = _survivor_head;
+ _length = _survivor_length;
+ if (_survivor_head != NULL) {
+ assert(_survivor_tail != NULL, "cause it shouldn't be");
+ assert(_survivor_length > 0, "invariant");
+ _survivor_tail->set_next_young_region(NULL);
+ }
+
+ // Don't clear the survivor list handles until the start of
+ // the next evacuation pause - we need it in order to re-tag
+ // the survivor regions from this evacuation pause as 'young'
+ // at the start of the next.
+
+ _g1h->g1_policy()->finished_recalculating_age_indexes(false /* is_survivors */);
+
+ assert(check_list_well_formed(), "young list should be well formed");
+}
+
+void YoungList::print() {
+ HeapRegion* lists[] = {_head, _survivor_head};
+ const char* names[] = {"YOUNG", "SURVIVOR"};
+
+ for (uint list = 0; list < ARRAY_SIZE(lists); ++list) {
+ gclog_or_tty->print_cr("%s LIST CONTENTS", names[list]);
+ HeapRegion *curr = lists[list];
+ if (curr == NULL)
+ gclog_or_tty->print_cr(" empty");
+ while (curr != NULL) {
+ gclog_or_tty->print_cr(" "HR_FORMAT", P: "PTR_FORMAT ", N: "PTR_FORMAT", age: %4d",
+ HR_FORMAT_PARAMS(curr),
+ p2i(curr->prev_top_at_mark_start()),
+ p2i(curr->next_top_at_mark_start()),
+ curr->age_in_surv_rate_group_cond());
+ curr = curr->get_next_young_region();
+ }
+ }
+
+ gclog_or_tty->cr();
+}
+
+void G1RegionMappingChangedListener::reset_from_card_cache(uint start_idx, size_t num_regions) {
+ HeapRegionRemSet::invalidate_from_card_cache(start_idx, num_regions);
+}
+
+void G1RegionMappingChangedListener::on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
+ // The from card cache is not the memory that is actually committed. So we cannot
+ // take advantage of the zero_filled parameter.
+ reset_from_card_cache(start_idx, num_regions);
+}
+
+void G1CollectedHeap::push_dirty_cards_region(HeapRegion* hr)
+{
+ // Claim the right to put the region on the dirty cards region list
+ // by installing a self pointer.
+ HeapRegion* next = hr->get_next_dirty_cards_region();
+ if (next == NULL) {
+ HeapRegion* res = (HeapRegion*)
+ Atomic::cmpxchg_ptr(hr, hr->next_dirty_cards_region_addr(),
+ NULL);
+ if (res == NULL) {
+ HeapRegion* head;
+ do {
+ // Put the region to the dirty cards region list.
+ head = _dirty_cards_region_list;
+ next = (HeapRegion*)
+ Atomic::cmpxchg_ptr(hr, &_dirty_cards_region_list, head);
+ if (next == head) {
+ assert(hr->get_next_dirty_cards_region() == hr,
+ "hr->get_next_dirty_cards_region() != hr");
+ if (next == NULL) {
+ // The last region in the list points to itself.
+ hr->set_next_dirty_cards_region(hr);
+ } else {
+ hr->set_next_dirty_cards_region(next);
+ }
+ }
+ } while (next != head);
+ }
+ }
+}
+
+HeapRegion* G1CollectedHeap::pop_dirty_cards_region()
+{
+ HeapRegion* head;
+ HeapRegion* hr;
+ do {
+ head = _dirty_cards_region_list;
+ if (head == NULL) {
+ return NULL;
+ }
+ HeapRegion* new_head = head->get_next_dirty_cards_region();
+ if (head == new_head) {
+ // The last region.
+ new_head = NULL;
+ }
+ hr = (HeapRegion*)Atomic::cmpxchg_ptr(new_head, &_dirty_cards_region_list,
+ head);
+ } while (hr != head);
+ assert(hr != NULL, "invariant");
+ hr->set_next_dirty_cards_region(NULL);
+ return hr;
+}
+
+// Returns true if the reference points to an object that
+// can move in an incremental collection.
+bool G1CollectedHeap::is_scavengable(const void* p) {
+ HeapRegion* hr = heap_region_containing(p);
+ return !hr->is_humongous();
+}
+
+// Private methods.
+
+HeapRegion*
+G1CollectedHeap::new_region_try_secondary_free_list(bool is_old) {
+ MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
+ while (!_secondary_free_list.is_empty() || free_regions_coming()) {
+ if (!_secondary_free_list.is_empty()) {
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
+ "secondary_free_list has %u entries",
+ _secondary_free_list.length());
+ }
+ // It looks as if there are free regions available on the
+ // secondary_free_list. Let's move them to the free_list and try
+ // again to allocate from it.
+ append_secondary_free_list();
+
+ assert(_hrm.num_free_regions() > 0, "if the secondary_free_list was not "
+ "empty we should have moved at least one entry to the free_list");
+ HeapRegion* res = _hrm.allocate_free_region(is_old);
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
+ "allocated "HR_FORMAT" from secondary_free_list",
+ HR_FORMAT_PARAMS(res));
+ }
+ return res;
+ }
+
+ // Wait here until we get notified either when (a) there are no
+ // more free regions coming or (b) some regions have been moved on
+ // the secondary_free_list.
+ SecondaryFreeList_lock->wait(Mutex::_no_safepoint_check_flag);
+ }
+
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
+ "could not allocate from secondary_free_list");
+ }
+ return NULL;
+}
+
+HeapRegion* G1CollectedHeap::new_region(size_t word_size, bool is_old, bool do_expand) {
+ assert(!is_humongous(word_size) || word_size <= HeapRegion::GrainWords,
+ "the only time we use this to allocate a humongous region is "
+ "when we are allocating a single humongous region");
+
+ HeapRegion* res;
+ if (G1StressConcRegionFreeing) {
+ if (!_secondary_free_list.is_empty()) {
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
+ "forced to look at the secondary_free_list");
+ }
+ res = new_region_try_secondary_free_list(is_old);
+ if (res != NULL) {
+ return res;
+ }
+ }
+ }
+
+ res = _hrm.allocate_free_region(is_old);
+
+ if (res == NULL) {
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [region alloc] : "
+ "res == NULL, trying the secondary_free_list");
+ }
+ res = new_region_try_secondary_free_list(is_old);
+ }
+ if (res == NULL && do_expand && _expand_heap_after_alloc_failure) {
+ // Currently, only attempts to allocate GC alloc regions set
+ // do_expand to true. So, we should only reach here during a
+ // safepoint. If this assumption changes we might have to
+ // reconsider the use of _expand_heap_after_alloc_failure.
+ assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+
+ ergo_verbose1(ErgoHeapSizing,
+ "attempt heap expansion",
+ ergo_format_reason("region allocation request failed")
+ ergo_format_byte("allocation request"),
+ word_size * HeapWordSize);
+ if (expand(word_size * HeapWordSize)) {
+ // Given that expand() succeeded in expanding the heap, and we
+ // always expand the heap by an amount aligned to the heap
+ // region size, the free list should in theory not be empty.
+ // In either case allocate_free_region() will check for NULL.
+ res = _hrm.allocate_free_region(is_old);
+ } else {
+ _expand_heap_after_alloc_failure = false;
+ }
+ }
+ return res;
+}
+
+HeapWord*
+G1CollectedHeap::humongous_obj_allocate_initialize_regions(uint first,
+ uint num_regions,
+ size_t word_size,
+ AllocationContext_t context) {
+ assert(first != G1_NO_HRM_INDEX, "pre-condition");
+ assert(is_humongous(word_size), "word_size should be humongous");
+ assert(num_regions * HeapRegion::GrainWords >= word_size, "pre-condition");
+
+ // Index of last region in the series + 1.
+ uint last = first + num_regions;
+
+ // We need to initialize the region(s) we just discovered. This is
+ // a bit tricky given that it can happen concurrently with
+ // refinement threads refining cards on these regions and
+ // potentially wanting to refine the BOT as they are scanning
+ // those cards (this can happen shortly after a cleanup; see CR
+ // 6991377). So we have to set up the region(s) carefully and in
+ // a specific order.
+
+ // The word size sum of all the regions we will allocate.
+ size_t word_size_sum = (size_t) num_regions * HeapRegion::GrainWords;
+ assert(word_size <= word_size_sum, "sanity");
+
+ // This will be the "starts humongous" region.
+ HeapRegion* first_hr = region_at(first);
+ // The header of the new object will be placed at the bottom of
+ // the first region.
+ HeapWord* new_obj = first_hr->bottom();
+ // This will be the new end of the first region in the series that
+ // should also match the end of the last region in the series.
+ HeapWord* new_end = new_obj + word_size_sum;
+ // This will be the new top of the first region that will reflect
+ // this allocation.
+ HeapWord* new_top = new_obj + word_size;
+
+ // First, we need to zero the header of the space that we will be
+ // allocating. When we update top further down, some refinement
+ // threads might try to scan the region. By zeroing the header we
+ // ensure that any thread that will try to scan the region will
+ // come across the zero klass word and bail out.
+ //
+ // NOTE: It would not have been correct to have used
+ // CollectedHeap::fill_with_object() and make the space look like
+ // an int array. The thread that is doing the allocation will
+ // later update the object header to a potentially different array
+ // type and, for a very short period of time, the klass and length
+ // fields will be inconsistent. This could cause a refinement
+ // thread to calculate the object size incorrectly.
+ Copy::fill_to_words(new_obj, oopDesc::header_size(), 0);
+
+ // We will set up the first region as "starts humongous". This
+ // will also update the BOT covering all the regions to reflect
+ // that there is a single object that starts at the bottom of the
+ // first region.
+ first_hr->set_starts_humongous(new_top, new_end);
+ first_hr->set_allocation_context(context);
+ // Then, if there are any, we will set up the "continues
+ // humongous" regions.
+ HeapRegion* hr = NULL;
+ for (uint i = first + 1; i < last; ++i) {
+ hr = region_at(i);
+ hr->set_continues_humongous(first_hr);
+ hr->set_allocation_context(context);
+ }
+ // If we have "continues humongous" regions (hr != NULL), then the
+ // end of the last one should match new_end.
+ assert(hr == NULL || hr->end() == new_end, "sanity");
+
+ // Up to this point no concurrent thread would have been able to
+ // do any scanning on any region in this series. All the top
+ // fields still point to bottom, so the intersection between
+ // [bottom,top] and [card_start,card_end] will be empty. Before we
+ // update the top fields, we'll do a storestore to make sure that
+ // no thread sees the update to top before the zeroing of the
+ // object header and the BOT initialization.
+ OrderAccess::storestore();
+
+ // Now that the BOT and the object header have been initialized,
+ // we can update top of the "starts humongous" region.
+ assert(first_hr->bottom() < new_top && new_top <= first_hr->end(),
+ "new_top should be in this region");
+ first_hr->set_top(new_top);
+ if (_hr_printer.is_active()) {
+ HeapWord* bottom = first_hr->bottom();
+ HeapWord* end = first_hr->orig_end();
+ if ((first + 1) == last) {
+ // the series has a single humongous region
+ _hr_printer.alloc(G1HRPrinter::SingleHumongous, first_hr, new_top);
+ } else {
+ // the series has more than one humongous regions
+ _hr_printer.alloc(G1HRPrinter::StartsHumongous, first_hr, end);
+ }
+ }
+
+ // Now, we will update the top fields of the "continues humongous"
+ // regions. The reason we need to do this is that, otherwise,
+ // these regions would look empty and this will confuse parts of
+ // G1. For example, the code that looks for a consecutive number
+ // of empty regions will consider them empty and try to
+ // re-allocate them. We can extend is_empty() to also include
+ // !is_continues_humongous(), but it is easier to just update the top
+ // fields here. The way we set top for all regions (i.e., top ==
+ // end for all regions but the last one, top == new_top for the
+ // last one) is actually used when we will free up the humongous
+ // region in free_humongous_region().
+ hr = NULL;
+ for (uint i = first + 1; i < last; ++i) {
+ hr = region_at(i);
+ if ((i + 1) == last) {
+ // last continues humongous region
+ assert(hr->bottom() < new_top && new_top <= hr->end(),
+ "new_top should fall on this region");
+ hr->set_top(new_top);
+ _hr_printer.alloc(G1HRPrinter::ContinuesHumongous, hr, new_top);
+ } else {
+ // not last one
+ assert(new_top > hr->end(), "new_top should be above this region");
+ hr->set_top(hr->end());
+ _hr_printer.alloc(G1HRPrinter::ContinuesHumongous, hr, hr->end());
+ }
+ }
+ // If we have continues humongous regions (hr != NULL), then the
+ // end of the last one should match new_end and its top should
+ // match new_top.
+ assert(hr == NULL ||
+ (hr->end() == new_end && hr->top() == new_top), "sanity");
+ check_bitmaps("Humongous Region Allocation", first_hr);
+
+ assert(first_hr->used() == word_size * HeapWordSize, "invariant");
+ _allocator->increase_used(first_hr->used());
+ _humongous_set.add(first_hr);
+
+ return new_obj;
+}
+
+// If could fit into free regions w/o expansion, try.
+// Otherwise, if can expand, do so.
+// Otherwise, if using ex regions might help, try with ex given back.
+HeapWord* G1CollectedHeap::humongous_obj_allocate(size_t word_size, AllocationContext_t context) {
+ assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
+
+ verify_region_sets_optional();
+
+ uint first = G1_NO_HRM_INDEX;
+ uint obj_regions = (uint)(align_size_up_(word_size, HeapRegion::GrainWords) / HeapRegion::GrainWords);
+
+ if (obj_regions == 1) {
+ // Only one region to allocate, try to use a fast path by directly allocating
+ // from the free lists. Do not try to expand here, we will potentially do that
+ // later.
+ HeapRegion* hr = new_region(word_size, true /* is_old */, false /* do_expand */);
+ if (hr != NULL) {
+ first = hr->hrm_index();
+ }
+ } else {
+ // We can't allocate humongous regions spanning more than one region while
+ // cleanupComplete() is running, since some of the regions we find to be
+ // empty might not yet be added to the free list. It is not straightforward
+ // to know in which list they are on so that we can remove them. We only
+ // need to do this if we need to allocate more than one region to satisfy the
+ // current humongous allocation request. If we are only allocating one region
+ // we use the one-region region allocation code (see above), that already
+ // potentially waits for regions from the secondary free list.
+ wait_while_free_regions_coming();
+ append_secondary_free_list_if_not_empty_with_lock();
+
+ // Policy: Try only empty regions (i.e. already committed first). Maybe we
+ // are lucky enough to find some.
+ first = _hrm.find_contiguous_only_empty(obj_regions);
+ if (first != G1_NO_HRM_INDEX) {
+ _hrm.allocate_free_regions_starting_at(first, obj_regions);
+ }
+ }
+
+ if (first == G1_NO_HRM_INDEX) {
+ // Policy: We could not find enough regions for the humongous object in the
+ // free list. Look through the heap to find a mix of free and uncommitted regions.
+ // If so, try expansion.
+ first = _hrm.find_contiguous_empty_or_unavailable(obj_regions);
+ if (first != G1_NO_HRM_INDEX) {
+ // We found something. Make sure these regions are committed, i.e. expand
+ // the heap. Alternatively we could do a defragmentation GC.
+ ergo_verbose1(ErgoHeapSizing,
+ "attempt heap expansion",
+ ergo_format_reason("humongous allocation request failed")
+ ergo_format_byte("allocation request"),
+ word_size * HeapWordSize);
+
+ _hrm.expand_at(first, obj_regions);
+ g1_policy()->record_new_heap_size(num_regions());
+
+#ifdef ASSERT
+ for (uint i = first; i < first + obj_regions; ++i) {
+ HeapRegion* hr = region_at(i);
+ assert(hr->is_free(), "sanity");
+ assert(hr->is_empty(), "sanity");
+ assert(is_on_master_free_list(hr), "sanity");
+ }
+#endif
+ _hrm.allocate_free_regions_starting_at(first, obj_regions);
+ } else {
+ // Policy: Potentially trigger a defragmentation GC.
+ }
+ }
+
+ HeapWord* result = NULL;
+ if (first != G1_NO_HRM_INDEX) {
+ result = humongous_obj_allocate_initialize_regions(first, obj_regions,
+ word_size, context);
+ assert(result != NULL, "it should always return a valid result");
+
+ // A successful humongous object allocation changes the used space
+ // information of the old generation so we need to recalculate the
+ // sizes and update the jstat counters here.
+ g1mm()->update_sizes();
+ }
+
+ verify_region_sets_optional();
+
+ return result;
+}
+
+HeapWord* G1CollectedHeap::allocate_new_tlab(size_t word_size) {
+ assert_heap_not_locked_and_not_at_safepoint();
+ assert(!is_humongous(word_size), "we do not allow humongous TLABs");
+
+ uint dummy_gc_count_before;
+ uint dummy_gclocker_retry_count = 0;
+ return attempt_allocation(word_size, &dummy_gc_count_before, &dummy_gclocker_retry_count);
+}
+
+HeapWord*
+G1CollectedHeap::mem_allocate(size_t word_size,
+ bool* gc_overhead_limit_was_exceeded) {
+ assert_heap_not_locked_and_not_at_safepoint();
+
+ // Loop until the allocation is satisfied, or unsatisfied after GC.
+ for (uint try_count = 1, gclocker_retry_count = 0; /* we'll return */; try_count += 1) {
+ uint gc_count_before;
+
+ HeapWord* result = NULL;
+ if (!is_humongous(word_size)) {
+ result = attempt_allocation(word_size, &gc_count_before, &gclocker_retry_count);
+ } else {
+ result = attempt_allocation_humongous(word_size, &gc_count_before, &gclocker_retry_count);
+ }
+ if (result != NULL) {
+ return result;
+ }
+
+ // Create the garbage collection operation...
+ VM_G1CollectForAllocation op(gc_count_before, word_size);
+ op.set_allocation_context(AllocationContext::current());
+
+ // ...and get the VM thread to execute it.
+ VMThread::execute(&op);
+
+ if (op.prologue_succeeded() && op.pause_succeeded()) {
+ // If the operation was successful we'll return the result even
+ // if it is NULL. If the allocation attempt failed immediately
+ // after a Full GC, it's unlikely we'll be able to allocate now.
+ HeapWord* result = op.result();
+ if (result != NULL && !is_humongous(word_size)) {
+ // Allocations that take place on VM operations do not do any
+ // card dirtying and we have to do it here. We only have to do
+ // this for non-humongous allocations, though.
+ dirty_young_block(result, word_size);
+ }
+ return result;
+ } else {
+ if (gclocker_retry_count > GCLockerRetryAllocationCount) {
+ return NULL;
+ }
+ assert(op.result() == NULL,
+ "the result should be NULL if the VM op did not succeed");
+ }
+
+ // Give a warning if we seem to be looping forever.
+ if ((QueuedAllocationWarningCount > 0) &&
+ (try_count % QueuedAllocationWarningCount == 0)) {
+ warning("G1CollectedHeap::mem_allocate retries %d times", try_count);
+ }
+ }
+
+ ShouldNotReachHere();
+ return NULL;
+}
+
+HeapWord* G1CollectedHeap::attempt_allocation_slow(size_t word_size,
+ AllocationContext_t context,
+ uint* gc_count_before_ret,
+ uint* gclocker_retry_count_ret) {
+ // Make sure you read the note in attempt_allocation_humongous().
+
+ assert_heap_not_locked_and_not_at_safepoint();
+ assert(!is_humongous(word_size), "attempt_allocation_slow() should not "
+ "be called for humongous allocation requests");
+
+ // We should only get here after the first-level allocation attempt
+ // (attempt_allocation()) failed to allocate.
+
+ // We will loop until a) we manage to successfully perform the
+ // allocation or b) we successfully schedule a collection which
+ // fails to perform the allocation. b) is the only case when we'll
+ // return NULL.
+ HeapWord* result = NULL;
+ for (int try_count = 1; /* we'll return */; try_count += 1) {
+ bool should_try_gc;
+ uint gc_count_before;
+
+ {
+ MutexLockerEx x(Heap_lock);
+ result = _allocator->mutator_alloc_region(context)->attempt_allocation_locked(word_size,
+ false /* bot_updates */);
+ if (result != NULL) {
+ return result;
+ }
+
+ // If we reach here, attempt_allocation_locked() above failed to
+ // allocate a new region. So the mutator alloc region should be NULL.
+ assert(_allocator->mutator_alloc_region(context)->get() == NULL, "only way to get here");
+
+ if (GC_locker::is_active_and_needs_gc()) {
+ if (g1_policy()->can_expand_young_list()) {
+ // No need for an ergo verbose message here,
+ // can_expand_young_list() does this when it returns true.
+ result = _allocator->mutator_alloc_region(context)->attempt_allocation_force(word_size,
+ false /* bot_updates */);
+ if (result != NULL) {
+ return result;
+ }
+ }
+ should_try_gc = false;
+ } else {
+ // The GCLocker may not be active but the GCLocker initiated
+ // GC may not yet have been performed (GCLocker::needs_gc()
+ // returns true). In this case we do not try this GC and
+ // wait until the GCLocker initiated GC is performed, and
+ // then retry the allocation.
+ if (GC_locker::needs_gc()) {
+ should_try_gc = false;
+ } else {
+ // Read the GC count while still holding the Heap_lock.
+ gc_count_before = total_collections();
+ should_try_gc = true;
+ }
+ }
+ }
+
+ if (should_try_gc) {
+ bool succeeded;
+ result = do_collection_pause(word_size, gc_count_before, &succeeded,
+ GCCause::_g1_inc_collection_pause);
+ if (result != NULL) {
+ assert(succeeded, "only way to get back a non-NULL result");
+ return result;
+ }
+
+ if (succeeded) {
+ // If we get here we successfully scheduled a collection which
+ // failed to allocate. No point in trying to allocate
+ // further. We'll just return NULL.
+ MutexLockerEx x(Heap_lock);
+ *gc_count_before_ret = total_collections();
+ return NULL;
+ }
+ } else {
+ if (*gclocker_retry_count_ret > GCLockerRetryAllocationCount) {
+ MutexLockerEx x(Heap_lock);
+ *gc_count_before_ret = total_collections();
+ return NULL;
+ }
+ // The GCLocker is either active or the GCLocker initiated
+ // GC has not yet been performed. Stall until it is and
+ // then retry the allocation.
+ GC_locker::stall_until_clear();
+ (*gclocker_retry_count_ret) += 1;
+ }
+
+ // We can reach here if we were unsuccessful in scheduling a
+ // collection (because another thread beat us to it) or if we were
+ // stalled due to the GC locker. In either can we should retry the
+ // allocation attempt in case another thread successfully
+ // performed a collection and reclaimed enough space. We do the
+ // first attempt (without holding the Heap_lock) here and the
+ // follow-on attempt will be at the start of the next loop
+ // iteration (after taking the Heap_lock).
+ result = _allocator->mutator_alloc_region(context)->attempt_allocation(word_size,
+ false /* bot_updates */);
+ if (result != NULL) {
+ return result;
+ }
+
+ // Give a warning if we seem to be looping forever.
+ if ((QueuedAllocationWarningCount > 0) &&
+ (try_count % QueuedAllocationWarningCount == 0)) {
+ warning("G1CollectedHeap::attempt_allocation_slow() "
+ "retries %d times", try_count);
+ }
+ }
+
+ ShouldNotReachHere();
+ return NULL;
+}
+
+HeapWord* G1CollectedHeap::attempt_allocation_humongous(size_t word_size,
+ uint* gc_count_before_ret,
+ uint* gclocker_retry_count_ret) {
+ // The structure of this method has a lot of similarities to
+ // attempt_allocation_slow(). The reason these two were not merged
+ // into a single one is that such a method would require several "if
+ // allocation is not humongous do this, otherwise do that"
+ // conditional paths which would obscure its flow. In fact, an early
+ // version of this code did use a unified method which was harder to
+ // follow and, as a result, it had subtle bugs that were hard to
+ // track down. So keeping these two methods separate allows each to
+ // be more readable. It will be good to keep these two in sync as
+ // much as possible.
+
+ assert_heap_not_locked_and_not_at_safepoint();
+ assert(is_humongous(word_size), "attempt_allocation_humongous() "
+ "should only be called for humongous allocations");
+
+ // Humongous objects can exhaust the heap quickly, so we should check if we
+ // need to start a marking cycle at each humongous object allocation. We do
+ // the check before we do the actual allocation. The reason for doing it
+ // before the allocation is that we avoid having to keep track of the newly
+ // allocated memory while we do a GC.
+ if (g1_policy()->need_to_start_conc_mark("concurrent humongous allocation",
+ word_size)) {
+ collect(GCCause::_g1_humongous_allocation);
+ }
+
+ // We will loop until a) we manage to successfully perform the
+ // allocation or b) we successfully schedule a collection which
+ // fails to perform the allocation. b) is the only case when we'll
+ // return NULL.
+ HeapWord* result = NULL;
+ for (int try_count = 1; /* we'll return */; try_count += 1) {
+ bool should_try_gc;
+ uint gc_count_before;
+
+ {
+ MutexLockerEx x(Heap_lock);
+
+ // Given that humongous objects are not allocated in young
+ // regions, we'll first try to do the allocation without doing a
+ // collection hoping that there's enough space in the heap.
+ result = humongous_obj_allocate(word_size, AllocationContext::current());
+ if (result != NULL) {
+ return result;
+ }
+
+ if (GC_locker::is_active_and_needs_gc()) {
+ should_try_gc = false;
+ } else {
+ // The GCLocker may not be active but the GCLocker initiated
+ // GC may not yet have been performed (GCLocker::needs_gc()
+ // returns true). In this case we do not try this GC and
+ // wait until the GCLocker initiated GC is performed, and
+ // then retry the allocation.
+ if (GC_locker::needs_gc()) {
+ should_try_gc = false;
+ } else {
+ // Read the GC count while still holding the Heap_lock.
+ gc_count_before = total_collections();
+ should_try_gc = true;
+ }
+ }
+ }
+
+ if (should_try_gc) {
+ // If we failed to allocate the humongous object, we should try to
+ // do a collection pause (if we're allowed) in case it reclaims
+ // enough space for the allocation to succeed after the pause.
+
+ bool succeeded;
+ result = do_collection_pause(word_size, gc_count_before, &succeeded,
+ GCCause::_g1_humongous_allocation);
+ if (result != NULL) {
+ assert(succeeded, "only way to get back a non-NULL result");
+ return result;
+ }
+
+ if (succeeded) {
+ // If we get here we successfully scheduled a collection which
+ // failed to allocate. No point in trying to allocate
+ // further. We'll just return NULL.
+ MutexLockerEx x(Heap_lock);
+ *gc_count_before_ret = total_collections();
+ return NULL;
+ }
+ } else {
+ if (*gclocker_retry_count_ret > GCLockerRetryAllocationCount) {
+ MutexLockerEx x(Heap_lock);
+ *gc_count_before_ret = total_collections();
+ return NULL;
+ }
+ // The GCLocker is either active or the GCLocker initiated
+ // GC has not yet been performed. Stall until it is and
+ // then retry the allocation.
+ GC_locker::stall_until_clear();
+ (*gclocker_retry_count_ret) += 1;
+ }
+
+ // We can reach here if we were unsuccessful in scheduling a
+ // collection (because another thread beat us to it) or if we were
+ // stalled due to the GC locker. In either can we should retry the
+ // allocation attempt in case another thread successfully
+ // performed a collection and reclaimed enough space. Give a
+ // warning if we seem to be looping forever.
+
+ if ((QueuedAllocationWarningCount > 0) &&
+ (try_count % QueuedAllocationWarningCount == 0)) {
+ warning("G1CollectedHeap::attempt_allocation_humongous() "
+ "retries %d times", try_count);
+ }
+ }
+
+ ShouldNotReachHere();
+ return NULL;
+}
+
+HeapWord* G1CollectedHeap::attempt_allocation_at_safepoint(size_t word_size,
+ AllocationContext_t context,
+ bool expect_null_mutator_alloc_region) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+ assert(_allocator->mutator_alloc_region(context)->get() == NULL ||
+ !expect_null_mutator_alloc_region,
+ "the current alloc region was unexpectedly found to be non-NULL");
+
+ if (!is_humongous(word_size)) {
+ return _allocator->mutator_alloc_region(context)->attempt_allocation_locked(word_size,
+ false /* bot_updates */);
+ } else {
+ HeapWord* result = humongous_obj_allocate(word_size, context);
+ if (result != NULL && g1_policy()->need_to_start_conc_mark("STW humongous allocation")) {
+ g1_policy()->set_initiate_conc_mark_if_possible();
+ }
+ return result;
+ }
+
+ ShouldNotReachHere();
+}
+
+class PostMCRemSetClearClosure: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
+ ModRefBarrierSet* _mr_bs;
+public:
+ PostMCRemSetClearClosure(G1CollectedHeap* g1h, ModRefBarrierSet* mr_bs) :
+ _g1h(g1h), _mr_bs(mr_bs) {}
+
+ bool doHeapRegion(HeapRegion* r) {
+ HeapRegionRemSet* hrrs = r->rem_set();
+
+ if (r->is_continues_humongous()) {
+ // We'll assert that the strong code root list and RSet is empty
+ assert(hrrs->strong_code_roots_list_length() == 0, "sanity");
+ assert(hrrs->occupied() == 0, "RSet should be empty");
+ return false;
+ }
+
+ _g1h->reset_gc_time_stamps(r);
+ hrrs->clear();
+ // You might think here that we could clear just the cards
+ // corresponding to the used region. But no: if we leave a dirty card
+ // in a region we might allocate into, then it would prevent that card
+ // from being enqueued, and cause it to be missed.
+ // Re: the performance cost: we shouldn't be doing full GC anyway!
+ _mr_bs->clear(MemRegion(r->bottom(), r->end()));
+
+ return false;
+ }
+};
+
+void G1CollectedHeap::clear_rsets_post_compaction() {
+ PostMCRemSetClearClosure rs_clear(this, g1_barrier_set());
+ heap_region_iterate(&rs_clear);
+}
+
+class RebuildRSOutOfRegionClosure: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
+ UpdateRSOopClosure _cl;
+public:
+ RebuildRSOutOfRegionClosure(G1CollectedHeap* g1, uint worker_i = 0) :
+ _cl(g1->g1_rem_set(), worker_i),
+ _g1h(g1)
+ { }
+
+ bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_continues_humongous()) {
+ _cl.set_from(r);
+ r->oop_iterate(&_cl);
+ }
+ return false;
+ }
+};
+
+class ParRebuildRSTask: public AbstractGangTask {
+ G1CollectedHeap* _g1;
+ HeapRegionClaimer _hrclaimer;
+
+public:
+ ParRebuildRSTask(G1CollectedHeap* g1) :
+ AbstractGangTask("ParRebuildRSTask"), _g1(g1), _hrclaimer(g1->workers()->active_workers()) {}
+
+ void work(uint worker_id) {
+ RebuildRSOutOfRegionClosure rebuild_rs(_g1, worker_id);
+ _g1->heap_region_par_iterate(&rebuild_rs, worker_id, &_hrclaimer);
+ }
+};
+
+class PostCompactionPrinterClosure: public HeapRegionClosure {
+private:
+ G1HRPrinter* _hr_printer;
+public:
+ bool doHeapRegion(HeapRegion* hr) {
+ assert(!hr->is_young(), "not expecting to find young regions");
+ if (hr->is_free()) {
+ // We only generate output for non-empty regions.
+ } else if (hr->is_starts_humongous()) {
+ if (hr->region_num() == 1) {
+ // single humongous region
+ _hr_printer->post_compaction(hr, G1HRPrinter::SingleHumongous);
+ } else {
+ _hr_printer->post_compaction(hr, G1HRPrinter::StartsHumongous);
+ }
+ } else if (hr->is_continues_humongous()) {
+ _hr_printer->post_compaction(hr, G1HRPrinter::ContinuesHumongous);
+ } else if (hr->is_old()) {
+ _hr_printer->post_compaction(hr, G1HRPrinter::Old);
+ } else {
+ ShouldNotReachHere();
+ }
+ return false;
+ }
+
+ PostCompactionPrinterClosure(G1HRPrinter* hr_printer)
+ : _hr_printer(hr_printer) { }
+};
+
+void G1CollectedHeap::print_hrm_post_compaction() {
+ PostCompactionPrinterClosure cl(hr_printer());
+ heap_region_iterate(&cl);
+}
+
+bool G1CollectedHeap::do_collection(bool explicit_gc,
+ bool clear_all_soft_refs,
+ size_t word_size) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+
+ if (GC_locker::check_active_before_gc()) {
+ return false;
+ }
+
+ STWGCTimer* gc_timer = G1MarkSweep::gc_timer();
+ gc_timer->register_gc_start();
+
+ SerialOldTracer* gc_tracer = G1MarkSweep::gc_tracer();
+ gc_tracer->report_gc_start(gc_cause(), gc_timer->gc_start());
+
+ SvcGCMarker sgcm(SvcGCMarker::FULL);
+ ResourceMark rm;
+
+ G1Log::update_level();
+ print_heap_before_gc();
+ trace_heap_before_gc(gc_tracer);
+
+ size_t metadata_prev_used = MetaspaceAux::used_bytes();
+
+ verify_region_sets_optional();
+
+ const bool do_clear_all_soft_refs = clear_all_soft_refs ||
+ collector_policy()->should_clear_all_soft_refs();
+
+ ClearedAllSoftRefs casr(do_clear_all_soft_refs, collector_policy());
+
+ {
+ IsGCActiveMark x;
+
+ // Timing
+ assert(gc_cause() != GCCause::_java_lang_system_gc || explicit_gc, "invariant");
+ TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
+
+ {
+ GCTraceTime t(GCCauseString("Full GC", gc_cause()), G1Log::fine(), true, NULL, gc_tracer->gc_id());
+ TraceCollectorStats tcs(g1mm()->full_collection_counters());
+ TraceMemoryManagerStats tms(true /* fullGC */, gc_cause());
+
+ g1_policy()->record_full_collection_start();
+
+ // Note: When we have a more flexible GC logging framework that
+ // allows us to add optional attributes to a GC log record we
+ // could consider timing and reporting how long we wait in the
+ // following two methods.
+ wait_while_free_regions_coming();
+ // If we start the compaction before the CM threads finish
+ // scanning the root regions we might trip them over as we'll
+ // be moving objects / updating references. So let's wait until
+ // they are done. By telling them to abort, they should complete
+ // early.
+ _cm->root_regions()->abort();
+ _cm->root_regions()->wait_until_scan_finished();
+ append_secondary_free_list_if_not_empty_with_lock();
+
+ gc_prologue(true);
+ increment_total_collections(true /* full gc */);
+ increment_old_marking_cycles_started();
+
+ assert(used() == recalculate_used(), "Should be equal");
+
+ verify_before_gc();
+
+ check_bitmaps("Full GC Start");
+ pre_full_gc_dump(gc_timer);
+
+ COMPILER2_PRESENT(DerivedPointerTable::clear());
+
+ // Disable discovery and empty the discovered lists
+ // for the CM ref processor.
+ ref_processor_cm()->disable_discovery();
+ ref_processor_cm()->abandon_partial_discovery();
+ ref_processor_cm()->verify_no_references_recorded();
+
+ // Abandon current iterations of concurrent marking and concurrent
+ // refinement, if any are in progress. We have to do this before
+ // wait_until_scan_finished() below.
+ concurrent_mark()->abort();
+
+ // Make sure we'll choose a new allocation region afterwards.
+ _allocator->release_mutator_alloc_region();
+ _allocator->abandon_gc_alloc_regions();
+ g1_rem_set()->cleanupHRRS();
+
+ // We should call this after we retire any currently active alloc
+ // regions so that all the ALLOC / RETIRE events are generated
+ // before the start GC event.
+ _hr_printer.start_gc(true /* full */, (size_t) total_collections());
+
+ // We may have added regions to the current incremental collection
+ // set between the last GC or pause and now. We need to clear the
+ // incremental collection set and then start rebuilding it afresh
+ // after this full GC.
+ abandon_collection_set(g1_policy()->inc_cset_head());
+ g1_policy()->clear_incremental_cset();
+ g1_policy()->stop_incremental_cset_building();
+
+ tear_down_region_sets(false /* free_list_only */);
+ g1_policy()->set_gcs_are_young(true);
+
+ // See the comments in g1CollectedHeap.hpp and
+ // G1CollectedHeap::ref_processing_init() about
+ // how reference processing currently works in G1.
+
+ // Temporarily make discovery by the STW ref processor single threaded (non-MT).
+ ReferenceProcessorMTDiscoveryMutator stw_rp_disc_ser(ref_processor_stw(), false);
+
+ // Temporarily clear the STW ref processor's _is_alive_non_header field.
+ ReferenceProcessorIsAliveMutator stw_rp_is_alive_null(ref_processor_stw(), NULL);
+
+ ref_processor_stw()->enable_discovery();
+ ref_processor_stw()->setup_policy(do_clear_all_soft_refs);
+
+ // Do collection work
+ {
+ HandleMark hm; // Discard invalid handles created during gc
+ G1MarkSweep::invoke_at_safepoint(ref_processor_stw(), do_clear_all_soft_refs);
+ }
+
+ assert(num_free_regions() == 0, "we should not have added any free regions");
+ rebuild_region_sets(false /* free_list_only */);
+
+ // Enqueue any discovered reference objects that have
+ // not been removed from the discovered lists.
+ ref_processor_stw()->enqueue_discovered_references();
+
+ COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
+
+ MemoryService::track_memory_usage();
+
+ assert(!ref_processor_stw()->discovery_enabled(), "Postcondition");
+ ref_processor_stw()->verify_no_references_recorded();
+
+ // Delete metaspaces for unloaded class loaders and clean up loader_data graph
+ ClassLoaderDataGraph::purge();
+ MetaspaceAux::verify_metrics();
+
+ // Note: since we've just done a full GC, concurrent
+ // marking is no longer active. Therefore we need not
+ // re-enable reference discovery for the CM ref processor.
+ // That will be done at the start of the next marking cycle.
+ assert(!ref_processor_cm()->discovery_enabled(), "Postcondition");
+ ref_processor_cm()->verify_no_references_recorded();
+
+ reset_gc_time_stamp();
+ // Since everything potentially moved, we will clear all remembered
+ // sets, and clear all cards. Later we will rebuild remembered
+ // sets. We will also reset the GC time stamps of the regions.
+ clear_rsets_post_compaction();
+ check_gc_time_stamps();
+
+ // Resize the heap if necessary.
+ resize_if_necessary_after_full_collection(explicit_gc ? 0 : word_size);
+
+ if (_hr_printer.is_active()) {
+ // We should do this after we potentially resize the heap so
+ // that all the COMMIT / UNCOMMIT events are generated before
+ // the end GC event.
+
+ print_hrm_post_compaction();
+ _hr_printer.end_gc(true /* full */, (size_t) total_collections());
+ }
+
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ if (hot_card_cache->use_cache()) {
+ hot_card_cache->reset_card_counts();
+ hot_card_cache->reset_hot_cache();
+ }
+
+ // Rebuild remembered sets of all regions.
+ uint n_workers =
+ AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
+ workers()->active_workers(),
+ Threads::number_of_non_daemon_threads());
+ assert(UseDynamicNumberOfGCThreads ||
+ n_workers == workers()->total_workers(),
+ "If not dynamic should be using all the workers");
+ workers()->set_active_workers(n_workers);
+ // Set parallel threads in the heap (_n_par_threads) only
+ // before a parallel phase and always reset it to 0 after
+ // the phase so that the number of parallel threads does
+ // no get carried forward to a serial phase where there
+ // may be code that is "possibly_parallel".
+ set_par_threads(n_workers);
+
+ ParRebuildRSTask rebuild_rs_task(this);
+ assert(UseDynamicNumberOfGCThreads ||
+ workers()->active_workers() == workers()->total_workers(),
+ "Unless dynamic should use total workers");
+ // Use the most recent number of active workers
+ assert(workers()->active_workers() > 0,
+ "Active workers not properly set");
+ set_par_threads(workers()->active_workers());
+ workers()->run_task(&rebuild_rs_task);
+ set_par_threads(0);
+
+ // Rebuild the strong code root lists for each region
+ rebuild_strong_code_roots();
+
+ if (true) { // FIXME
+ MetaspaceGC::compute_new_size();
+ }
+
+#ifdef TRACESPINNING
+ ParallelTaskTerminator::print_termination_counts();
+#endif
+
+ // Discard all rset updates
+ JavaThread::dirty_card_queue_set().abandon_logs();
+ assert(dirty_card_queue_set().completed_buffers_num() == 0, "DCQS should be empty");
+
+ _young_list->reset_sampled_info();
+ // At this point there should be no regions in the
+ // entire heap tagged as young.
+ assert(check_young_list_empty(true /* check_heap */),
+ "young list should be empty at this point");
+
+ // Update the number of full collections that have been completed.
+ increment_old_marking_cycles_completed(false /* concurrent */);
+
+ _hrm.verify_optional();
+ verify_region_sets_optional();
+
+ verify_after_gc();
+
+ // Clear the previous marking bitmap, if needed for bitmap verification.
+ // Note we cannot do this when we clear the next marking bitmap in
+ // ConcurrentMark::abort() above since VerifyDuringGC verifies the
+ // objects marked during a full GC against the previous bitmap.
+ // But we need to clear it before calling check_bitmaps below since
+ // the full GC has compacted objects and updated TAMS but not updated
+ // the prev bitmap.
+ if (G1VerifyBitmaps) {
+ ((CMBitMap*) concurrent_mark()->prevMarkBitMap())->clearAll();
+ }
+ check_bitmaps("Full GC End");
+
+ // Start a new incremental collection set for the next pause
+ assert(g1_policy()->collection_set() == NULL, "must be");
+ g1_policy()->start_incremental_cset_building();
+
+ clear_cset_fast_test();
+
+ _allocator->init_mutator_alloc_region();
+
+ g1_policy()->record_full_collection_end();
+
+ if (G1Log::fine()) {
+ g1_policy()->print_heap_transition();
+ }
+
+ // We must call G1MonitoringSupport::update_sizes() in the same scoping level
+ // as an active TraceMemoryManagerStats object (i.e. before the destructor for the
+ // TraceMemoryManagerStats is called) so that the G1 memory pools are updated
+ // before any GC notifications are raised.
+ g1mm()->update_sizes();
+
+ gc_epilogue(true);
+ }
+
+ if (G1Log::finer()) {
+ g1_policy()->print_detailed_heap_transition(true /* full */);
+ }
+
+ print_heap_after_gc();
+ trace_heap_after_gc(gc_tracer);
+
+ post_full_gc_dump(gc_timer);
+
+ gc_timer->register_gc_end();
+ gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions());
+ }
+
+ return true;
+}
+
+void G1CollectedHeap::do_full_collection(bool clear_all_soft_refs) {
+ // do_collection() will return whether it succeeded in performing
+ // the GC. Currently, there is no facility on the
+ // do_full_collection() API to notify the caller than the collection
+ // did not succeed (e.g., because it was locked out by the GC
+ // locker). So, right now, we'll ignore the return value.
+ bool dummy = do_collection(true, /* explicit_gc */
+ clear_all_soft_refs,
+ 0 /* word_size */);
+}
+
+// This code is mostly copied from TenuredGeneration.
+void
+G1CollectedHeap::
+resize_if_necessary_after_full_collection(size_t word_size) {
+ // Include the current allocation, if any, and bytes that will be
+ // pre-allocated to support collections, as "used".
+ const size_t used_after_gc = used();
+ const size_t capacity_after_gc = capacity();
+ const size_t free_after_gc = capacity_after_gc - used_after_gc;
+
+ // This is enforced in arguments.cpp.
+ assert(MinHeapFreeRatio <= MaxHeapFreeRatio,
+ "otherwise the code below doesn't make sense");
+
+ // We don't have floating point command-line arguments
+ const double minimum_free_percentage = (double) MinHeapFreeRatio / 100.0;
+ const double maximum_used_percentage = 1.0 - minimum_free_percentage;
+ const double maximum_free_percentage = (double) MaxHeapFreeRatio / 100.0;
+ const double minimum_used_percentage = 1.0 - maximum_free_percentage;
+
+ const size_t min_heap_size = collector_policy()->min_heap_byte_size();
+ const size_t max_heap_size = collector_policy()->max_heap_byte_size();
+
+ // We have to be careful here as these two calculations can overflow
+ // 32-bit size_t's.
+ double used_after_gc_d = (double) used_after_gc;
+ double minimum_desired_capacity_d = used_after_gc_d / maximum_used_percentage;
+ double maximum_desired_capacity_d = used_after_gc_d / minimum_used_percentage;
+
+ // Let's make sure that they are both under the max heap size, which
+ // by default will make them fit into a size_t.
+ double desired_capacity_upper_bound = (double) max_heap_size;
+ minimum_desired_capacity_d = MIN2(minimum_desired_capacity_d,
+ desired_capacity_upper_bound);
+ maximum_desired_capacity_d = MIN2(maximum_desired_capacity_d,
+ desired_capacity_upper_bound);
+
+ // We can now safely turn them into size_t's.
+ size_t minimum_desired_capacity = (size_t) minimum_desired_capacity_d;
+ size_t maximum_desired_capacity = (size_t) maximum_desired_capacity_d;
+
+ // This assert only makes sense here, before we adjust them
+ // with respect to the min and max heap size.
+ assert(minimum_desired_capacity <= maximum_desired_capacity,
+ err_msg("minimum_desired_capacity = "SIZE_FORMAT", "
+ "maximum_desired_capacity = "SIZE_FORMAT,
+ minimum_desired_capacity, maximum_desired_capacity));
+
+ // Should not be greater than the heap max size. No need to adjust
+ // it with respect to the heap min size as it's a lower bound (i.e.,
+ // we'll try to make the capacity larger than it, not smaller).
+ minimum_desired_capacity = MIN2(minimum_desired_capacity, max_heap_size);
+ // Should not be less than the heap min size. No need to adjust it
+ // with respect to the heap max size as it's an upper bound (i.e.,
+ // we'll try to make the capacity smaller than it, not greater).
+ maximum_desired_capacity = MAX2(maximum_desired_capacity, min_heap_size);
+
+ if (capacity_after_gc < minimum_desired_capacity) {
+ // Don't expand unless it's significant
+ size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
+ ergo_verbose4(ErgoHeapSizing,
+ "attempt heap expansion",
+ ergo_format_reason("capacity lower than "
+ "min desired capacity after Full GC")
+ ergo_format_byte("capacity")
+ ergo_format_byte("occupancy")
+ ergo_format_byte_perc("min desired capacity"),
+ capacity_after_gc, used_after_gc,
+ minimum_desired_capacity, (double) MinHeapFreeRatio);
+ expand(expand_bytes);
+
+ // No expansion, now see if we want to shrink
+ } else if (capacity_after_gc > maximum_desired_capacity) {
+ // Capacity too large, compute shrinking size
+ size_t shrink_bytes = capacity_after_gc - maximum_desired_capacity;
+ ergo_verbose4(ErgoHeapSizing,
+ "attempt heap shrinking",
+ ergo_format_reason("capacity higher than "
+ "max desired capacity after Full GC")
+ ergo_format_byte("capacity")
+ ergo_format_byte("occupancy")
+ ergo_format_byte_perc("max desired capacity"),
+ capacity_after_gc, used_after_gc,
+ maximum_desired_capacity, (double) MaxHeapFreeRatio);
+ shrink(shrink_bytes);
+ }
+}
+
+
+HeapWord*
+G1CollectedHeap::satisfy_failed_allocation(size_t word_size,
+ AllocationContext_t context,
+ bool* succeeded) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+
+ *succeeded = true;
+ // Let's attempt the allocation first.
+ HeapWord* result =
+ attempt_allocation_at_safepoint(word_size,
+ context,
+ false /* expect_null_mutator_alloc_region */);
+ if (result != NULL) {
+ assert(*succeeded, "sanity");
+ return result;
+ }
+
+ // In a G1 heap, we're supposed to keep allocation from failing by
+ // incremental pauses. Therefore, at least for now, we'll favor
+ // expansion over collection. (This might change in the future if we can
+ // do something smarter than full collection to satisfy a failed alloc.)
+ result = expand_and_allocate(word_size, context);
+ if (result != NULL) {
+ assert(*succeeded, "sanity");
+ return result;
+ }
+
+ // Expansion didn't work, we'll try to do a Full GC.
+ bool gc_succeeded = do_collection(false, /* explicit_gc */
+ false, /* clear_all_soft_refs */
+ word_size);
+ if (!gc_succeeded) {
+ *succeeded = false;
+ return NULL;
+ }
+
+ // Retry the allocation
+ result = attempt_allocation_at_safepoint(word_size,
+ context,
+ true /* expect_null_mutator_alloc_region */);
+ if (result != NULL) {
+ assert(*succeeded, "sanity");
+ return result;
+ }
+
+ // Then, try a Full GC that will collect all soft references.
+ gc_succeeded = do_collection(false, /* explicit_gc */
+ true, /* clear_all_soft_refs */
+ word_size);
+ if (!gc_succeeded) {
+ *succeeded = false;
+ return NULL;
+ }
+
+ // Retry the allocation once more
+ result = attempt_allocation_at_safepoint(word_size,
+ context,
+ true /* expect_null_mutator_alloc_region */);
+ if (result != NULL) {
+ assert(*succeeded, "sanity");
+ return result;
+ }
+
+ assert(!collector_policy()->should_clear_all_soft_refs(),
+ "Flag should have been handled and cleared prior to this point");
+
+ // What else? We might try synchronous finalization later. If the total
+ // space available is large enough for the allocation, then a more
+ // complete compaction phase than we've tried so far might be
+ // appropriate.
+ assert(*succeeded, "sanity");
+ return NULL;
+}
+
+// Attempting to expand the heap sufficiently
+// to support an allocation of the given "word_size". If
+// successful, perform the allocation and return the address of the
+// allocated block, or else "NULL".
+
+HeapWord* G1CollectedHeap::expand_and_allocate(size_t word_size, AllocationContext_t context) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+
+ verify_region_sets_optional();
+
+ size_t expand_bytes = MAX2(word_size * HeapWordSize, MinHeapDeltaBytes);
+ ergo_verbose1(ErgoHeapSizing,
+ "attempt heap expansion",
+ ergo_format_reason("allocation request failed")
+ ergo_format_byte("allocation request"),
+ word_size * HeapWordSize);
+ if (expand(expand_bytes)) {
+ _hrm.verify_optional();
+ verify_region_sets_optional();
+ return attempt_allocation_at_safepoint(word_size,
+ context,
+ false /* expect_null_mutator_alloc_region */);
+ }
+ return NULL;
+}
+
+bool G1CollectedHeap::expand(size_t expand_bytes) {
+ size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
+ aligned_expand_bytes = align_size_up(aligned_expand_bytes,
+ HeapRegion::GrainBytes);
+ ergo_verbose2(ErgoHeapSizing,
+ "expand the heap",
+ ergo_format_byte("requested expansion amount")
+ ergo_format_byte("attempted expansion amount"),
+ expand_bytes, aligned_expand_bytes);
+
+ if (is_maximal_no_gc()) {
+ ergo_verbose0(ErgoHeapSizing,
+ "did not expand the heap",
+ ergo_format_reason("heap already fully expanded"));
+ return false;
+ }
+
+ uint regions_to_expand = (uint)(aligned_expand_bytes / HeapRegion::GrainBytes);
+ assert(regions_to_expand > 0, "Must expand by at least one region");
+
+ uint expanded_by = _hrm.expand_by(regions_to_expand);
+
+ if (expanded_by > 0) {
+ size_t actual_expand_bytes = expanded_by * HeapRegion::GrainBytes;
+ assert(actual_expand_bytes <= aligned_expand_bytes, "post-condition");
+ g1_policy()->record_new_heap_size(num_regions());
+ } else {
+ ergo_verbose0(ErgoHeapSizing,
+ "did not expand the heap",
+ ergo_format_reason("heap expansion operation failed"));
+ // The expansion of the virtual storage space was unsuccessful.
+ // Let's see if it was because we ran out of swap.
+ if (G1ExitOnExpansionFailure &&
+ _hrm.available() >= regions_to_expand) {
+ // We had head room...
+ vm_exit_out_of_memory(aligned_expand_bytes, OOM_MMAP_ERROR, "G1 heap expansion");
+ }
+ }
+ return regions_to_expand > 0;
+}
+
+void G1CollectedHeap::shrink_helper(size_t shrink_bytes) {
+ size_t aligned_shrink_bytes =
+ ReservedSpace::page_align_size_down(shrink_bytes);
+ aligned_shrink_bytes = align_size_down(aligned_shrink_bytes,
+ HeapRegion::GrainBytes);
+ uint num_regions_to_remove = (uint)(shrink_bytes / HeapRegion::GrainBytes);
+
+ uint num_regions_removed = _hrm.shrink_by(num_regions_to_remove);
+ size_t shrunk_bytes = num_regions_removed * HeapRegion::GrainBytes;
+
+ ergo_verbose3(ErgoHeapSizing,
+ "shrink the heap",
+ ergo_format_byte("requested shrinking amount")
+ ergo_format_byte("aligned shrinking amount")
+ ergo_format_byte("attempted shrinking amount"),
+ shrink_bytes, aligned_shrink_bytes, shrunk_bytes);
+ if (num_regions_removed > 0) {
+ g1_policy()->record_new_heap_size(num_regions());
+ } else {
+ ergo_verbose0(ErgoHeapSizing,
+ "did not shrink the heap",
+ ergo_format_reason("heap shrinking operation failed"));
+ }
+}
+
+void G1CollectedHeap::shrink(size_t shrink_bytes) {
+ verify_region_sets_optional();
+
+ // We should only reach here at the end of a Full GC which means we
+ // should not not be holding to any GC alloc regions. The method
+ // below will make sure of that and do any remaining clean up.
+ _allocator->abandon_gc_alloc_regions();
+
+ // Instead of tearing down / rebuilding the free lists here, we
+ // could instead use the remove_all_pending() method on free_list to
+ // remove only the ones that we need to remove.
+ tear_down_region_sets(true /* free_list_only */);
+ shrink_helper(shrink_bytes);
+ rebuild_region_sets(true /* free_list_only */);
+
+ _hrm.verify_optional();
+ verify_region_sets_optional();
+}
+
+// Public methods.
+
+#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
+#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
+#endif // _MSC_VER
+
+
+G1CollectedHeap::G1CollectedHeap(G1CollectorPolicy* policy_) :
+ CollectedHeap(),
+ _g1_policy(policy_),
+ _dirty_card_queue_set(false),
+ _into_cset_dirty_card_queue_set(false),
+ _is_alive_closure_cm(this),
+ _is_alive_closure_stw(this),
+ _ref_processor_cm(NULL),
+ _ref_processor_stw(NULL),
+ _bot_shared(NULL),
+ _evac_failure_scan_stack(NULL),
+ _mark_in_progress(false),
+ _cg1r(NULL),
+ _g1mm(NULL),
+ _refine_cte_cl(NULL),
+ _full_collection(false),
+ _secondary_free_list("Secondary Free List", new SecondaryFreeRegionListMtSafeChecker()),
+ _old_set("Old Set", false /* humongous */, new OldRegionSetMtSafeChecker()),
+ _humongous_set("Master Humongous Set", true /* humongous */, new HumongousRegionSetMtSafeChecker()),
+ _humongous_reclaim_candidates(),
+ _has_humongous_reclaim_candidates(false),
+ _free_regions_coming(false),
+ _young_list(new YoungList(this)),
+ _gc_time_stamp(0),
+ _survivor_plab_stats(YoungPLABSize, PLABWeight),
+ _old_plab_stats(OldPLABSize, PLABWeight),
+ _expand_heap_after_alloc_failure(true),
+ _surviving_young_words(NULL),
+ _old_marking_cycles_started(0),
+ _old_marking_cycles_completed(0),
+ _concurrent_cycle_started(false),
+ _heap_summary_sent(false),
+ _in_cset_fast_test(),
+ _dirty_cards_region_list(NULL),
+ _worker_cset_start_region(NULL),
+ _worker_cset_start_region_time_stamp(NULL),
+ _gc_timer_stw(new (ResourceObj::C_HEAP, mtGC) STWGCTimer()),
+ _gc_timer_cm(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
+ _gc_tracer_stw(new (ResourceObj::C_HEAP, mtGC) G1NewTracer()),
+ _gc_tracer_cm(new (ResourceObj::C_HEAP, mtGC) G1OldTracer()) {
+
+ _workers = new FlexibleWorkGang("GC Thread", ParallelGCThreads,
+ /* are_GC_task_threads */true,
+ /* are_ConcurrentGC_threads */false);
+ _workers->initialize_workers();
+
+ _allocator = G1Allocator::create_allocator(this);
+ _humongous_object_threshold_in_words = HeapRegion::GrainWords / 2;
+
+ int n_queues = MAX2((int)ParallelGCThreads, 1);
+ _task_queues = new RefToScanQueueSet(n_queues);
+
+ uint n_rem_sets = HeapRegionRemSet::num_par_rem_sets();
+ assert(n_rem_sets > 0, "Invariant.");
+
+ _worker_cset_start_region = NEW_C_HEAP_ARRAY(HeapRegion*, n_queues, mtGC);
+ _worker_cset_start_region_time_stamp = NEW_C_HEAP_ARRAY(uint, n_queues, mtGC);
+ _evacuation_failed_info_array = NEW_C_HEAP_ARRAY(EvacuationFailedInfo, n_queues, mtGC);
+
+ for (int i = 0; i < n_queues; i++) {
+ RefToScanQueue* q = new RefToScanQueue();
+ q->initialize();
+ _task_queues->register_queue(i, q);
+ ::new (&_evacuation_failed_info_array[i]) EvacuationFailedInfo();
+ }
+ clear_cset_start_regions();
+
+ // Initialize the G1EvacuationFailureALot counters and flags.
+ NOT_PRODUCT(reset_evacuation_should_fail();)
+
+ guarantee(_task_queues != NULL, "task_queues allocation failure.");
+}
+
+G1RegionToSpaceMapper* G1CollectedHeap::create_aux_memory_mapper(const char* description,
+ size_t size,
+ size_t translation_factor) {
+ size_t preferred_page_size = os::page_size_for_region_unaligned(size, 1);
+ // Allocate a new reserved space, preferring to use large pages.
+ ReservedSpace rs(size, preferred_page_size);
+ G1RegionToSpaceMapper* result =
+ G1RegionToSpaceMapper::create_mapper(rs,
+ size,
+ rs.alignment(),
+ HeapRegion::GrainBytes,
+ translation_factor,
+ mtGC);
+ if (TracePageSizes) {
+ gclog_or_tty->print_cr("G1 '%s': pg_sz=" SIZE_FORMAT " base=" PTR_FORMAT " size=" SIZE_FORMAT " alignment=" SIZE_FORMAT " reqsize=" SIZE_FORMAT,
+ description, preferred_page_size, p2i(rs.base()), rs.size(), rs.alignment(), size);
+ }
+ return result;
+}
+
+jint G1CollectedHeap::initialize() {
+ CollectedHeap::pre_initialize();
+ os::enable_vtime();
+
+ G1Log::init();
+
+ // Necessary to satisfy locking discipline assertions.
+
+ MutexLocker x(Heap_lock);
+
+ // We have to initialize the printer before committing the heap, as
+ // it will be used then.
+ _hr_printer.set_active(G1PrintHeapRegions);
+
+ // While there are no constraints in the GC code that HeapWordSize
+ // be any particular value, there are multiple other areas in the
+ // system which believe this to be true (e.g. oop->object_size in some
+ // cases incorrectly returns the size in wordSize units rather than
+ // HeapWordSize).
+ guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
+
+ size_t init_byte_size = collector_policy()->initial_heap_byte_size();
+ size_t max_byte_size = collector_policy()->max_heap_byte_size();
+ size_t heap_alignment = collector_policy()->heap_alignment();
+
+ // Ensure that the sizes are properly aligned.
+ Universe::check_alignment(init_byte_size, HeapRegion::GrainBytes, "g1 heap");
+ Universe::check_alignment(max_byte_size, HeapRegion::GrainBytes, "g1 heap");
+ Universe::check_alignment(max_byte_size, heap_alignment, "g1 heap");
+
+ _refine_cte_cl = new RefineCardTableEntryClosure();
+
+ _cg1r = new ConcurrentG1Refine(this, _refine_cte_cl);
+
+ // Reserve the maximum.
+
+ // When compressed oops are enabled, the preferred heap base
+ // is calculated by subtracting the requested size from the
+ // 32Gb boundary and using the result as the base address for
+ // heap reservation. If the requested size is not aligned to
+ // HeapRegion::GrainBytes (i.e. the alignment that is passed
+ // into the ReservedHeapSpace constructor) then the actual
+ // base of the reserved heap may end up differing from the
+ // address that was requested (i.e. the preferred heap base).
+ // If this happens then we could end up using a non-optimal
+ // compressed oops mode.
+
+ ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size,
+ heap_alignment);
+
+ initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*)(heap_rs.base() + heap_rs.size()));
+
+ // Create the barrier set for the entire reserved region.
+ G1SATBCardTableLoggingModRefBS* bs
+ = new G1SATBCardTableLoggingModRefBS(reserved_region());
+ bs->initialize();
+ assert(bs->is_a(BarrierSet::G1SATBCTLogging), "sanity");
+ set_barrier_set(bs);
+
+ // Also create a G1 rem set.
+ _g1_rem_set = new G1RemSet(this, g1_barrier_set());
+
+ // Carve out the G1 part of the heap.
+
+ ReservedSpace g1_rs = heap_rs.first_part(max_byte_size);
+ size_t page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
+ G1RegionToSpaceMapper* heap_storage =
+ G1RegionToSpaceMapper::create_mapper(g1_rs,
+ g1_rs.size(),
+ page_size,
+ HeapRegion::GrainBytes,
+ 1,
+ mtJavaHeap);
+ os::trace_page_sizes("G1 Heap", collector_policy()->min_heap_byte_size(),
+ max_byte_size, page_size,
+ heap_rs.base(),
+ heap_rs.size());
+ heap_storage->set_mapping_changed_listener(&_listener);
+
+ // Create storage for the BOT, card table, card counts table (hot card cache) and the bitmaps.
+ G1RegionToSpaceMapper* bot_storage =
+ create_aux_memory_mapper("Block offset table",
+ G1BlockOffsetSharedArray::compute_size(g1_rs.size() / HeapWordSize),
+ G1BlockOffsetSharedArray::heap_map_factor());
+
+ ReservedSpace cardtable_rs(G1SATBCardTableLoggingModRefBS::compute_size(g1_rs.size() / HeapWordSize));
+ G1RegionToSpaceMapper* cardtable_storage =
+ create_aux_memory_mapper("Card table",
+ G1SATBCardTableLoggingModRefBS::compute_size(g1_rs.size() / HeapWordSize),
+ G1SATBCardTableLoggingModRefBS::heap_map_factor());
+
+ G1RegionToSpaceMapper* card_counts_storage =
+ create_aux_memory_mapper("Card counts table",
+ G1CardCounts::compute_size(g1_rs.size() / HeapWordSize),
+ G1CardCounts::heap_map_factor());
+
+ size_t bitmap_size = CMBitMap::compute_size(g1_rs.size());
+ G1RegionToSpaceMapper* prev_bitmap_storage =
+ create_aux_memory_mapper("Prev Bitmap", bitmap_size, CMBitMap::heap_map_factor());
+ G1RegionToSpaceMapper* next_bitmap_storage =
+ create_aux_memory_mapper("Next Bitmap", bitmap_size, CMBitMap::heap_map_factor());
+
+ _hrm.initialize(heap_storage, prev_bitmap_storage, next_bitmap_storage, bot_storage, cardtable_storage, card_counts_storage);
+ g1_barrier_set()->initialize(cardtable_storage);
+ // Do later initialization work for concurrent refinement.
+ _cg1r->init(card_counts_storage);
+
+ // 6843694 - ensure that the maximum region index can fit
+ // in the remembered set structures.
+ const uint max_region_idx = (1U << (sizeof(RegionIdx_t)*BitsPerByte-1)) - 1;
+ guarantee((max_regions() - 1) <= max_region_idx, "too many regions");
+
+ size_t max_cards_per_region = ((size_t)1 << (sizeof(CardIdx_t)*BitsPerByte-1)) - 1;
+ guarantee(HeapRegion::CardsPerRegion > 0, "make sure it's initialized");
+ guarantee(HeapRegion::CardsPerRegion < max_cards_per_region,
+ "too many cards per region");
+
+ FreeRegionList::set_unrealistically_long_length(max_regions() + 1);
+
+ _bot_shared = new G1BlockOffsetSharedArray(reserved_region(), bot_storage);
+
+ {
+ HeapWord* start = _hrm.reserved().start();
+ HeapWord* end = _hrm.reserved().end();
+ size_t granularity = HeapRegion::GrainBytes;
+
+ _in_cset_fast_test.initialize(start, end, granularity);
+ _humongous_reclaim_candidates.initialize(start, end, granularity);
+ }
+
+ // Create the ConcurrentMark data structure and thread.
+ // (Must do this late, so that "max_regions" is defined.)
+ _cm = new ConcurrentMark(this, prev_bitmap_storage, next_bitmap_storage);
+ if (_cm == NULL || !_cm->completed_initialization()) {
+ vm_shutdown_during_initialization("Could not create/initialize ConcurrentMark");
+ return JNI_ENOMEM;
+ }
+ _cmThread = _cm->cmThread();
+
+ // Initialize the from_card cache structure of HeapRegionRemSet.
+ HeapRegionRemSet::init_heap(max_regions());
+
+ // Now expand into the initial heap size.
+ if (!expand(init_byte_size)) {
+ vm_shutdown_during_initialization("Failed to allocate initial heap.");
+ return JNI_ENOMEM;
+ }
+
+ // Perform any initialization actions delegated to the policy.
+ g1_policy()->init();
+
+ JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon,
+ SATB_Q_FL_lock,
+ G1SATBProcessCompletedThreshold,
+ Shared_SATB_Q_lock);
+
+ JavaThread::dirty_card_queue_set().initialize(_refine_cte_cl,
+ DirtyCardQ_CBL_mon,
+ DirtyCardQ_FL_lock,
+ concurrent_g1_refine()->yellow_zone(),
+ concurrent_g1_refine()->red_zone(),
+ Shared_DirtyCardQ_lock);
+
+ dirty_card_queue_set().initialize(NULL, // Should never be called by the Java code
+ DirtyCardQ_CBL_mon,
+ DirtyCardQ_FL_lock,
+ -1, // never trigger processing
+ -1, // no limit on length
+ Shared_DirtyCardQ_lock,
+ &JavaThread::dirty_card_queue_set());
+
+ // Initialize the card queue set used to hold cards containing
+ // references into the collection set.
+ _into_cset_dirty_card_queue_set.initialize(NULL, // Should never be called by the Java code
+ DirtyCardQ_CBL_mon,
+ DirtyCardQ_FL_lock,
+ -1, // never trigger processing
+ -1, // no limit on length
+ Shared_DirtyCardQ_lock,
+ &JavaThread::dirty_card_queue_set());
+
+ // Here we allocate the dummy HeapRegion that is required by the
+ // G1AllocRegion class.
+ HeapRegion* dummy_region = _hrm.get_dummy_region();
+
+ // We'll re-use the same region whether the alloc region will
+ // require BOT updates or not and, if it doesn't, then a non-young
+ // region will complain that it cannot support allocations without
+ // BOT updates. So we'll tag the dummy region as eden to avoid that.
+ dummy_region->set_eden();
+ // Make sure it's full.
+ dummy_region->set_top(dummy_region->end());
+ G1AllocRegion::setup(this, dummy_region);
+
+ _allocator->init_mutator_alloc_region();
+
+ // Do create of the monitoring and management support so that
+ // values in the heap have been properly initialized.
+ _g1mm = new G1MonitoringSupport(this);
+
+ G1StringDedup::initialize();
+
+ return JNI_OK;
+}
+
+void G1CollectedHeap::stop() {
+ // Stop all concurrent threads. We do this to make sure these threads
+ // do not continue to execute and access resources (e.g. gclog_or_tty)
+ // that are destroyed during shutdown.
+ _cg1r->stop();
+ _cmThread->stop();
+ if (G1StringDedup::is_enabled()) {
+ G1StringDedup::stop();
+ }
+}
+
+size_t G1CollectedHeap::conservative_max_heap_alignment() {
+ return HeapRegion::max_region_size();
+}
+
+void G1CollectedHeap::post_initialize() {
+ CollectedHeap::post_initialize();
+ ref_processing_init();
+}
+
+void G1CollectedHeap::ref_processing_init() {
+ // Reference processing in G1 currently works as follows:
+ //
+ // * There are two reference processor instances. One is
+ // used to record and process discovered references
+ // during concurrent marking; the other is used to
+ // record and process references during STW pauses
+ // (both full and incremental).
+ // * Both ref processors need to 'span' the entire heap as
+ // the regions in the collection set may be dotted around.
+ //
+ // * For the concurrent marking ref processor:
+ // * Reference discovery is enabled at initial marking.
+ // * Reference discovery is disabled and the discovered
+ // references processed etc during remarking.
+ // * Reference discovery is MT (see below).
+ // * Reference discovery requires a barrier (see below).
+ // * Reference processing may or may not be MT
+ // (depending on the value of ParallelRefProcEnabled
+ // and ParallelGCThreads).
+ // * A full GC disables reference discovery by the CM
+ // ref processor and abandons any entries on it's
+ // discovered lists.
+ //
+ // * For the STW processor:
+ // * Non MT discovery is enabled at the start of a full GC.
+ // * Processing and enqueueing during a full GC is non-MT.
+ // * During a full GC, references are processed after marking.
+ //
+ // * Discovery (may or may not be MT) is enabled at the start
+ // of an incremental evacuation pause.
+ // * References are processed near the end of a STW evacuation pause.
+ // * For both types of GC:
+ // * Discovery is atomic - i.e. not concurrent.
+ // * Reference discovery will not need a barrier.
+
+ MemRegion mr = reserved_region();
+
+ // Concurrent Mark ref processor
+ _ref_processor_cm =
+ new ReferenceProcessor(mr, // span
+ ParallelRefProcEnabled && (ParallelGCThreads > 1),
+ // mt processing
+ (int) ParallelGCThreads,
+ // degree of mt processing
+ (ParallelGCThreads > 1) || (ConcGCThreads > 1),
+ // mt discovery
+ (int) MAX2(ParallelGCThreads, ConcGCThreads),
+ // degree of mt discovery
+ false,
+ // Reference discovery is not atomic
+ &_is_alive_closure_cm);
+ // is alive closure
+ // (for efficiency/performance)
+
+ // STW ref processor
+ _ref_processor_stw =
+ new ReferenceProcessor(mr, // span
+ ParallelRefProcEnabled && (ParallelGCThreads > 1),
+ // mt processing
+ MAX2((int)ParallelGCThreads, 1),
+ // degree of mt processing
+ (ParallelGCThreads > 1),
+ // mt discovery
+ MAX2((int)ParallelGCThreads, 1),
+ // degree of mt discovery
+ true,
+ // Reference discovery is atomic
+ &_is_alive_closure_stw);
+ // is alive closure
+ // (for efficiency/performance)
+}
+
+size_t G1CollectedHeap::capacity() const {
+ return _hrm.length() * HeapRegion::GrainBytes;
+}
+
+void G1CollectedHeap::reset_gc_time_stamps(HeapRegion* hr) {
+ assert(!hr->is_continues_humongous(), "pre-condition");
+ hr->reset_gc_time_stamp();
+ if (hr->is_starts_humongous()) {
+ uint first_index = hr->hrm_index() + 1;
+ uint last_index = hr->last_hc_index();
+ for (uint i = first_index; i < last_index; i += 1) {
+ HeapRegion* chr = region_at(i);
+ assert(chr->is_continues_humongous(), "sanity");
+ chr->reset_gc_time_stamp();
+ }
+ }
+}
+
+#ifndef PRODUCT
+
+class CheckGCTimeStampsHRClosure : public HeapRegionClosure {
+private:
+ unsigned _gc_time_stamp;
+ bool _failures;
+
+public:
+ CheckGCTimeStampsHRClosure(unsigned gc_time_stamp) :
+ _gc_time_stamp(gc_time_stamp), _failures(false) { }
+
+ virtual bool doHeapRegion(HeapRegion* hr) {
+ unsigned region_gc_time_stamp = hr->get_gc_time_stamp();
+ if (_gc_time_stamp != region_gc_time_stamp) {
+ gclog_or_tty->print_cr("Region "HR_FORMAT" has GC time stamp = %d, "
+ "expected %d", HR_FORMAT_PARAMS(hr),
+ region_gc_time_stamp, _gc_time_stamp);
+ _failures = true;
+ }
+ return false;
+ }
+
+ bool failures() { return _failures; }
+};
+
+void G1CollectedHeap::check_gc_time_stamps() {
+ CheckGCTimeStampsHRClosure cl(_gc_time_stamp);
+ heap_region_iterate(&cl);
+ guarantee(!cl.failures(), "all GC time stamps should have been reset");
+}
+#endif // PRODUCT
+
+void G1CollectedHeap::iterate_dirty_card_closure(CardTableEntryClosure* cl,
+ DirtyCardQueue* into_cset_dcq,
+ bool concurrent,
+ uint worker_i) {
+ // Clean cards in the hot card cache
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ hot_card_cache->drain(worker_i, g1_rem_set(), into_cset_dcq);
+
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ size_t n_completed_buffers = 0;
+ while (dcqs.apply_closure_to_completed_buffer(cl, worker_i, 0, true)) {
+ n_completed_buffers++;
+ }
+ g1_policy()->phase_times()->record_thread_work_item(G1GCPhaseTimes::UpdateRS, worker_i, n_completed_buffers);
+ dcqs.clear_n_completed_buffers();
+ assert(!dcqs.completed_buffers_exist_dirty(), "Completed buffers exist!");
+}
+
+
+// Computes the sum of the storage used by the various regions.
+size_t G1CollectedHeap::used() const {
+ return _allocator->used();
+}
+
+size_t G1CollectedHeap::used_unlocked() const {
+ return _allocator->used_unlocked();
+}
+
+class SumUsedClosure: public HeapRegionClosure {
+ size_t _used;
+public:
+ SumUsedClosure() : _used(0) {}
+ bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_continues_humongous()) {
+ _used += r->used();
+ }
+ return false;
+ }
+ size_t result() { return _used; }
+};
+
+size_t G1CollectedHeap::recalculate_used() const {
+ double recalculate_used_start = os::elapsedTime();
+
+ SumUsedClosure blk;
+ heap_region_iterate(&blk);
+
+ g1_policy()->phase_times()->record_evac_fail_recalc_used_time((os::elapsedTime() - recalculate_used_start) * 1000.0);
+ return blk.result();
+}
+
+bool G1CollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
+ switch (cause) {
+ case GCCause::_gc_locker: return GCLockerInvokesConcurrent;
+ case GCCause::_java_lang_system_gc: return ExplicitGCInvokesConcurrent;
+ case GCCause::_g1_humongous_allocation: return true;
+ case GCCause::_update_allocation_context_stats_inc: return true;
+ case GCCause::_wb_conc_mark: return true;
+ default: return false;
+ }
+}
+
+#ifndef PRODUCT
+void G1CollectedHeap::allocate_dummy_regions() {
+ // Let's fill up most of the region
+ size_t word_size = HeapRegion::GrainWords - 1024;
+ // And as a result the region we'll allocate will be humongous.
+ guarantee(is_humongous(word_size), "sanity");
+
+ for (uintx i = 0; i < G1DummyRegionsPerGC; ++i) {
+ // Let's use the existing mechanism for the allocation
+ HeapWord* dummy_obj = humongous_obj_allocate(word_size,
+ AllocationContext::system());
+ if (dummy_obj != NULL) {
+ MemRegion mr(dummy_obj, word_size);
+ CollectedHeap::fill_with_object(mr);
+ } else {
+ // If we can't allocate once, we probably cannot allocate
+ // again. Let's get out of the loop.
+ break;
+ }
+ }
+}
+#endif // !PRODUCT
+
+void G1CollectedHeap::increment_old_marking_cycles_started() {
+ assert(_old_marking_cycles_started == _old_marking_cycles_completed ||
+ _old_marking_cycles_started == _old_marking_cycles_completed + 1,
+ err_msg("Wrong marking cycle count (started: %d, completed: %d)",
+ _old_marking_cycles_started, _old_marking_cycles_completed));
+
+ _old_marking_cycles_started++;
+}
+
+void G1CollectedHeap::increment_old_marking_cycles_completed(bool concurrent) {
+ MonitorLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
+
+ // We assume that if concurrent == true, then the caller is a
+ // concurrent thread that was joined the Suspendible Thread
+ // Set. If there's ever a cheap way to check this, we should add an
+ // assert here.
+
+ // Given that this method is called at the end of a Full GC or of a
+ // concurrent cycle, and those can be nested (i.e., a Full GC can
+ // interrupt a concurrent cycle), the number of full collections
+ // completed should be either one (in the case where there was no
+ // nesting) or two (when a Full GC interrupted a concurrent cycle)
+ // behind the number of full collections started.
+
+ // This is the case for the inner caller, i.e. a Full GC.
+ assert(concurrent ||
+ (_old_marking_cycles_started == _old_marking_cycles_completed + 1) ||
+ (_old_marking_cycles_started == _old_marking_cycles_completed + 2),
+ err_msg("for inner caller (Full GC): _old_marking_cycles_started = %u "
+ "is inconsistent with _old_marking_cycles_completed = %u",
+ _old_marking_cycles_started, _old_marking_cycles_completed));
+
+ // This is the case for the outer caller, i.e. the concurrent cycle.
+ assert(!concurrent ||
+ (_old_marking_cycles_started == _old_marking_cycles_completed + 1),
+ err_msg("for outer caller (concurrent cycle): "
+ "_old_marking_cycles_started = %u "
+ "is inconsistent with _old_marking_cycles_completed = %u",
+ _old_marking_cycles_started, _old_marking_cycles_completed));
+
+ _old_marking_cycles_completed += 1;
+
+ // We need to clear the "in_progress" flag in the CM thread before
+ // we wake up any waiters (especially when ExplicitInvokesConcurrent
+ // is set) so that if a waiter requests another System.gc() it doesn't
+ // incorrectly see that a marking cycle is still in progress.
+ if (concurrent) {
+ _cmThread->clear_in_progress();
+ }
+
+ // This notify_all() will ensure that a thread that called
+ // System.gc() with (with ExplicitGCInvokesConcurrent set or not)
+ // and it's waiting for a full GC to finish will be woken up. It is
+ // waiting in VM_G1IncCollectionPause::doit_epilogue().
+ FullGCCount_lock->notify_all();
+}
+
+void G1CollectedHeap::register_concurrent_cycle_start(const Ticks& start_time) {
+ _concurrent_cycle_started = true;
+ _gc_timer_cm->register_gc_start(start_time);
+
+ _gc_tracer_cm->report_gc_start(gc_cause(), _gc_timer_cm->gc_start());
+ trace_heap_before_gc(_gc_tracer_cm);
+}
+
+void G1CollectedHeap::register_concurrent_cycle_end() {
+ if (_concurrent_cycle_started) {
+ if (_cm->has_aborted()) {
+ _gc_tracer_cm->report_concurrent_mode_failure();
+ }
+
+ _gc_timer_cm->register_gc_end();
+ _gc_tracer_cm->report_gc_end(_gc_timer_cm->gc_end(), _gc_timer_cm->time_partitions());
+
+ // Clear state variables to prepare for the next concurrent cycle.
+ _concurrent_cycle_started = false;
+ _heap_summary_sent = false;
+ }
+}
+
+void G1CollectedHeap::trace_heap_after_concurrent_cycle() {
+ if (_concurrent_cycle_started) {
+ // This function can be called when:
+ // the cleanup pause is run
+ // the concurrent cycle is aborted before the cleanup pause.
+ // the concurrent cycle is aborted after the cleanup pause,
+ // but before the concurrent cycle end has been registered.
+ // Make sure that we only send the heap information once.
+ if (!_heap_summary_sent) {
+ trace_heap_after_gc(_gc_tracer_cm);
+ _heap_summary_sent = true;
+ }
+ }
+}
+
+G1YCType G1CollectedHeap::yc_type() {
+ bool is_young = g1_policy()->gcs_are_young();
+ bool is_initial_mark = g1_policy()->during_initial_mark_pause();
+ bool is_during_mark = mark_in_progress();
+
+ if (is_initial_mark) {
+ return InitialMark;
+ } else if (is_during_mark) {
+ return DuringMark;
+ } else if (is_young) {
+ return Normal;
+ } else {
+ return Mixed;
+ }
+}
+
+void G1CollectedHeap::collect(GCCause::Cause cause) {
+ assert_heap_not_locked();
+
+ uint gc_count_before;
+ uint old_marking_count_before;
+ uint full_gc_count_before;
+ bool retry_gc;
+
+ do {
+ retry_gc = false;
+
+ {
+ MutexLocker ml(Heap_lock);
+
+ // Read the GC count while holding the Heap_lock
+ gc_count_before = total_collections();
+ full_gc_count_before = total_full_collections();
+ old_marking_count_before = _old_marking_cycles_started;
+ }
+
+ if (should_do_concurrent_full_gc(cause)) {
+ // Schedule an initial-mark evacuation pause that will start a
+ // concurrent cycle. We're setting word_size to 0 which means that
+ // we are not requesting a post-GC allocation.
+ VM_G1IncCollectionPause op(gc_count_before,
+ 0, /* word_size */
+ true, /* should_initiate_conc_mark */
+ g1_policy()->max_pause_time_ms(),
+ cause);
+ op.set_allocation_context(AllocationContext::current());
+
+ VMThread::execute(&op);
+ if (!op.pause_succeeded()) {
+ if (old_marking_count_before == _old_marking_cycles_started) {
+ retry_gc = op.should_retry_gc();
+ } else {
+ // A Full GC happened while we were trying to schedule the
+ // initial-mark GC. No point in starting a new cycle given
+ // that the whole heap was collected anyway.
+ }
+
+ if (retry_gc) {
+ if (GC_locker::is_active_and_needs_gc()) {
+ GC_locker::stall_until_clear();
+ }
+ }
+ }
+ } else {
+ if (cause == GCCause::_gc_locker || cause == GCCause::_wb_young_gc
+ DEBUG_ONLY(|| cause == GCCause::_scavenge_alot)) {
+
+ // Schedule a standard evacuation pause. We're setting word_size
+ // to 0 which means that we are not requesting a post-GC allocation.
+ VM_G1IncCollectionPause op(gc_count_before,
+ 0, /* word_size */
+ false, /* should_initiate_conc_mark */
+ g1_policy()->max_pause_time_ms(),
+ cause);
+ VMThread::execute(&op);
+ } else {
+ // Schedule a Full GC.
+ VM_G1CollectFull op(gc_count_before, full_gc_count_before, cause);
+ VMThread::execute(&op);
+ }
+ }
+ } while (retry_gc);
+}
+
+bool G1CollectedHeap::is_in(const void* p) const {
+ if (_hrm.reserved().contains(p)) {
+ // Given that we know that p is in the reserved space,
+ // heap_region_containing_raw() should successfully
+ // return the containing region.
+ HeapRegion* hr = heap_region_containing_raw(p);
+ return hr->is_in(p);
+ } else {
+ return false;
+ }
+}
+
+#ifdef ASSERT
+bool G1CollectedHeap::is_in_exact(const void* p) const {
+ bool contains = reserved_region().contains(p);
+ bool available = _hrm.is_available(addr_to_region((HeapWord*)p));
+ if (contains && available) {
+ return true;
+ } else {
+ return false;
+ }
+}
+#endif
+
+// Iteration functions.
+
+// Applies an ExtendedOopClosure onto all references of objects within a HeapRegion.
+
+class IterateOopClosureRegionClosure: public HeapRegionClosure {
+ ExtendedOopClosure* _cl;
+public:
+ IterateOopClosureRegionClosure(ExtendedOopClosure* cl) : _cl(cl) {}
+ bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_continues_humongous()) {
+ r->oop_iterate(_cl);
+ }
+ return false;
+ }
+};
+
+// Iterates an ObjectClosure over all objects within a HeapRegion.
+
+class IterateObjectClosureRegionClosure: public HeapRegionClosure {
+ ObjectClosure* _cl;
+public:
+ IterateObjectClosureRegionClosure(ObjectClosure* cl) : _cl(cl) {}
+ bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_continues_humongous()) {
+ r->object_iterate(_cl);
+ }
+ return false;
+ }
+};
+
+void G1CollectedHeap::object_iterate(ObjectClosure* cl) {
+ IterateObjectClosureRegionClosure blk(cl);
+ heap_region_iterate(&blk);
+}
+
+void G1CollectedHeap::heap_region_iterate(HeapRegionClosure* cl) const {
+ _hrm.iterate(cl);
+}
+
+void
+G1CollectedHeap::heap_region_par_iterate(HeapRegionClosure* cl,
+ uint worker_id,
+ HeapRegionClaimer *hrclaimer,
+ bool concurrent) const {
+ _hrm.par_iterate(cl, worker_id, hrclaimer, concurrent);
+}
+
+// Clear the cached CSet starting regions and (more importantly)
+// the time stamps. Called when we reset the GC time stamp.
+void G1CollectedHeap::clear_cset_start_regions() {
+ assert(_worker_cset_start_region != NULL, "sanity");
+ assert(_worker_cset_start_region_time_stamp != NULL, "sanity");
+
+ int n_queues = MAX2((int)ParallelGCThreads, 1);
+ for (int i = 0; i < n_queues; i++) {
+ _worker_cset_start_region[i] = NULL;
+ _worker_cset_start_region_time_stamp[i] = 0;
+ }
+}
+
+// Given the id of a worker, obtain or calculate a suitable
+// starting region for iterating over the current collection set.
+HeapRegion* G1CollectedHeap::start_cset_region_for_worker(uint worker_i) {
+ assert(get_gc_time_stamp() > 0, "should have been updated by now");
+
+ HeapRegion* result = NULL;
+ unsigned gc_time_stamp = get_gc_time_stamp();
+
+ if (_worker_cset_start_region_time_stamp[worker_i] == gc_time_stamp) {
+ // Cached starting region for current worker was set
+ // during the current pause - so it's valid.
+ // Note: the cached starting heap region may be NULL
+ // (when the collection set is empty).
+ result = _worker_cset_start_region[worker_i];
+ assert(result == NULL || result->in_collection_set(), "sanity");
+ return result;
+ }
+
+ // The cached entry was not valid so let's calculate
+ // a suitable starting heap region for this worker.
+
+ // We want the parallel threads to start their collection
+ // set iteration at different collection set regions to
+ // avoid contention.
+ // If we have:
+ // n collection set regions
+ // p threads
+ // Then thread t will start at region floor ((t * n) / p)
+
+ result = g1_policy()->collection_set();
+ uint cs_size = g1_policy()->cset_region_length();
+ uint active_workers = workers()->active_workers();
+ assert(UseDynamicNumberOfGCThreads ||
+ active_workers == workers()->total_workers(),
+ "Unless dynamic should use total workers");
+
+ uint end_ind = (cs_size * worker_i) / active_workers;
+ uint start_ind = 0;
+
+ if (worker_i > 0 &&
+ _worker_cset_start_region_time_stamp[worker_i - 1] == gc_time_stamp) {
+ // Previous workers starting region is valid
+ // so let's iterate from there
+ start_ind = (cs_size * (worker_i - 1)) / active_workers;
+ result = _worker_cset_start_region[worker_i - 1];
+ }
+
+ for (uint i = start_ind; i < end_ind; i++) {
+ result = result->next_in_collection_set();
+ }
+
+ // Note: the calculated starting heap region may be NULL
+ // (when the collection set is empty).
+ assert(result == NULL || result->in_collection_set(), "sanity");
+ assert(_worker_cset_start_region_time_stamp[worker_i] != gc_time_stamp,
+ "should be updated only once per pause");
+ _worker_cset_start_region[worker_i] = result;
+ OrderAccess::storestore();
+ _worker_cset_start_region_time_stamp[worker_i] = gc_time_stamp;
+ return result;
+}
+
+void G1CollectedHeap::collection_set_iterate(HeapRegionClosure* cl) {
+ HeapRegion* r = g1_policy()->collection_set();
+ while (r != NULL) {
+ HeapRegion* next = r->next_in_collection_set();
+ if (cl->doHeapRegion(r)) {
+ cl->incomplete();
+ return;
+ }
+ r = next;
+ }
+}
+
+void G1CollectedHeap::collection_set_iterate_from(HeapRegion* r,
+ HeapRegionClosure *cl) {
+ if (r == NULL) {
+ // The CSet is empty so there's nothing to do.
+ return;
+ }
+
+ assert(r->in_collection_set(),
+ "Start region must be a member of the collection set.");
+ HeapRegion* cur = r;
+ while (cur != NULL) {
+ HeapRegion* next = cur->next_in_collection_set();
+ if (cl->doHeapRegion(cur) && false) {
+ cl->incomplete();
+ return;
+ }
+ cur = next;
+ }
+ cur = g1_policy()->collection_set();
+ while (cur != r) {
+ HeapRegion* next = cur->next_in_collection_set();
+ if (cl->doHeapRegion(cur) && false) {
+ cl->incomplete();
+ return;
+ }
+ cur = next;
+ }
+}
+
+HeapRegion* G1CollectedHeap::next_compaction_region(const HeapRegion* from) const {
+ HeapRegion* result = _hrm.next_region_in_heap(from);
+ while (result != NULL && result->is_humongous()) {
+ result = _hrm.next_region_in_heap(result);
+ }
+ return result;
+}
+
+HeapWord* G1CollectedHeap::block_start(const void* addr) const {
+ HeapRegion* hr = heap_region_containing(addr);
+ return hr->block_start(addr);
+}
+
+size_t G1CollectedHeap::block_size(const HeapWord* addr) const {
+ HeapRegion* hr = heap_region_containing(addr);
+ return hr->block_size(addr);
+}
+
+bool G1CollectedHeap::block_is_obj(const HeapWord* addr) const {
+ HeapRegion* hr = heap_region_containing(addr);
+ return hr->block_is_obj(addr);
+}
+
+bool G1CollectedHeap::supports_tlab_allocation() const {
+ return true;
+}
+
+size_t G1CollectedHeap::tlab_capacity(Thread* ignored) const {
+ return (_g1_policy->young_list_target_length() - young_list()->survivor_length()) * HeapRegion::GrainBytes;
+}
+
+size_t G1CollectedHeap::tlab_used(Thread* ignored) const {
+ return young_list()->eden_used_bytes();
+}
+
+// For G1 TLABs should not contain humongous objects, so the maximum TLAB size
+// must be smaller than the humongous object limit.
+size_t G1CollectedHeap::max_tlab_size() const {
+ return align_size_down(_humongous_object_threshold_in_words - 1, MinObjAlignment);
+}
+
+size_t G1CollectedHeap::unsafe_max_tlab_alloc(Thread* ignored) const {
+ // Return the remaining space in the cur alloc region, but not less than
+ // the min TLAB size.
+
+ // Also, this value can be at most the humongous object threshold,
+ // since we can't allow tlabs to grow big enough to accommodate
+ // humongous objects.
+
+ HeapRegion* hr = _allocator->mutator_alloc_region(AllocationContext::current())->get();
+ size_t max_tlab = max_tlab_size() * wordSize;
+ if (hr == NULL) {
+ return max_tlab;
+ } else {
+ return MIN2(MAX2(hr->free(), (size_t) MinTLABSize), max_tlab);
+ }
+}
+
+size_t G1CollectedHeap::max_capacity() const {
+ return _hrm.reserved().byte_size();
+}
+
+jlong G1CollectedHeap::millis_since_last_gc() {
+ // assert(false, "NYI");
+ return 0;
+}
+
+void G1CollectedHeap::prepare_for_verify() {
+ if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
+ ensure_parsability(false);
+ }
+ g1_rem_set()->prepare_for_verify();
+}
+
+bool G1CollectedHeap::allocated_since_marking(oop obj, HeapRegion* hr,
+ VerifyOption vo) {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking:
+ return hr->obj_allocated_since_prev_marking(obj);
+ case VerifyOption_G1UseNextMarking:
+ return hr->obj_allocated_since_next_marking(obj);
+ case VerifyOption_G1UseMarkWord:
+ return false;
+ default:
+ ShouldNotReachHere();
+ }
+ return false; // keep some compilers happy
+}
+
+HeapWord* G1CollectedHeap::top_at_mark_start(HeapRegion* hr, VerifyOption vo) {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking: return hr->prev_top_at_mark_start();
+ case VerifyOption_G1UseNextMarking: return hr->next_top_at_mark_start();
+ case VerifyOption_G1UseMarkWord: return NULL;
+ default: ShouldNotReachHere();
+ }
+ return NULL; // keep some compilers happy
+}
+
+bool G1CollectedHeap::is_marked(oop obj, VerifyOption vo) {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking: return isMarkedPrev(obj);
+ case VerifyOption_G1UseNextMarking: return isMarkedNext(obj);
+ case VerifyOption_G1UseMarkWord: return obj->is_gc_marked();
+ default: ShouldNotReachHere();
+ }
+ return false; // keep some compilers happy
+}
+
+const char* G1CollectedHeap::top_at_mark_start_str(VerifyOption vo) {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking: return "PTAMS";
+ case VerifyOption_G1UseNextMarking: return "NTAMS";
+ case VerifyOption_G1UseMarkWord: return "NONE";
+ default: ShouldNotReachHere();
+ }
+ return NULL; // keep some compilers happy
+}
+
+class VerifyRootsClosure: public OopClosure {
+private:
+ G1CollectedHeap* _g1h;
+ VerifyOption _vo;
+ bool _failures;
+public:
+ // _vo == UsePrevMarking -> use "prev" marking information,
+ // _vo == UseNextMarking -> use "next" marking information,
+ // _vo == UseMarkWord -> use mark word from object header.
+ VerifyRootsClosure(VerifyOption vo) :
+ _g1h(G1CollectedHeap::heap()),
+ _vo(vo),
+ _failures(false) { }
+
+ bool failures() { return _failures; }
+
+ template <class T> void do_oop_nv(T* p) {
+ T heap_oop = oopDesc::load_heap_oop(p);
+ if (!oopDesc::is_null(heap_oop)) {
+ oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
+ if (_g1h->is_obj_dead_cond(obj, _vo)) {
+ gclog_or_tty->print_cr("Root location "PTR_FORMAT" "
+ "points to dead obj "PTR_FORMAT, p2i(p), p2i(obj));
+ if (_vo == VerifyOption_G1UseMarkWord) {
+ gclog_or_tty->print_cr(" Mark word: "INTPTR_FORMAT, (intptr_t)obj->mark());
+ }
+ obj->print_on(gclog_or_tty);
+ _failures = true;
+ }
+ }
+ }
+
+ void do_oop(oop* p) { do_oop_nv(p); }
+ void do_oop(narrowOop* p) { do_oop_nv(p); }
+};
+
+class G1VerifyCodeRootOopClosure: public OopClosure {
+ G1CollectedHeap* _g1h;
+ OopClosure* _root_cl;
+ nmethod* _nm;
+ VerifyOption _vo;
+ bool _failures;
+
+ template <class T> void do_oop_work(T* p) {
+ // First verify that this root is live
+ _root_cl->do_oop(p);
+
+ if (!G1VerifyHeapRegionCodeRoots) {
+ // We're not verifying the code roots attached to heap region.
+ return;
+ }
+
+ // Don't check the code roots during marking verification in a full GC
+ if (_vo == VerifyOption_G1UseMarkWord) {
+ return;
+ }
+
+ // Now verify that the current nmethod (which contains p) is
+ // in the code root list of the heap region containing the
+ // object referenced by p.
+
+ T heap_oop = oopDesc::load_heap_oop(p);
+ if (!oopDesc::is_null(heap_oop)) {
+ oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
+
+ // Now fetch the region containing the object
+ HeapRegion* hr = _g1h->heap_region_containing(obj);
+ HeapRegionRemSet* hrrs = hr->rem_set();
+ // Verify that the strong code root list for this region
+ // contains the nmethod
+ if (!hrrs->strong_code_roots_list_contains(_nm)) {
+ gclog_or_tty->print_cr("Code root location "PTR_FORMAT" "
+ "from nmethod "PTR_FORMAT" not in strong "
+ "code roots for region ["PTR_FORMAT","PTR_FORMAT")",
+ p2i(p), p2i(_nm), p2i(hr->bottom()), p2i(hr->end()));
+ _failures = true;
+ }
+ }
+ }
+
+public:
+ G1VerifyCodeRootOopClosure(G1CollectedHeap* g1h, OopClosure* root_cl, VerifyOption vo):
+ _g1h(g1h), _root_cl(root_cl), _vo(vo), _nm(NULL), _failures(false) {}
+
+ void do_oop(oop* p) { do_oop_work(p); }
+ void do_oop(narrowOop* p) { do_oop_work(p); }
+
+ void set_nmethod(nmethod* nm) { _nm = nm; }
+ bool failures() { return _failures; }
+};
+
+class G1VerifyCodeRootBlobClosure: public CodeBlobClosure {
+ G1VerifyCodeRootOopClosure* _oop_cl;
+
+public:
+ G1VerifyCodeRootBlobClosure(G1VerifyCodeRootOopClosure* oop_cl):
+ _oop_cl(oop_cl) {}
+
+ void do_code_blob(CodeBlob* cb) {
+ nmethod* nm = cb->as_nmethod_or_null();
+ if (nm != NULL) {
+ _oop_cl->set_nmethod(nm);
+ nm->oops_do(_oop_cl);
+ }
+ }
+};
+
+class YoungRefCounterClosure : public OopClosure {
+ G1CollectedHeap* _g1h;
+ int _count;
+ public:
+ YoungRefCounterClosure(G1CollectedHeap* g1h) : _g1h(g1h), _count(0) {}
+ void do_oop(oop* p) { if (_g1h->is_in_young(*p)) { _count++; } }
+ void do_oop(narrowOop* p) { ShouldNotReachHere(); }
+
+ int count() { return _count; }
+ void reset_count() { _count = 0; };
+};
+
+class VerifyKlassClosure: public KlassClosure {
+ YoungRefCounterClosure _young_ref_counter_closure;
+ OopClosure *_oop_closure;
+ public:
+ VerifyKlassClosure(G1CollectedHeap* g1h, OopClosure* cl) : _young_ref_counter_closure(g1h), _oop_closure(cl) {}
+ void do_klass(Klass* k) {
+ k->oops_do(_oop_closure);
+
+ _young_ref_counter_closure.reset_count();
+ k->oops_do(&_young_ref_counter_closure);
+ if (_young_ref_counter_closure.count() > 0) {
+ guarantee(k->has_modified_oops(), err_msg("Klass " PTR_FORMAT ", has young refs but is not dirty.", p2i(k)));
+ }
+ }
+};
+
+class VerifyLivenessOopClosure: public OopClosure {
+ G1CollectedHeap* _g1h;
+ VerifyOption _vo;
+public:
+ VerifyLivenessOopClosure(G1CollectedHeap* g1h, VerifyOption vo):
+ _g1h(g1h), _vo(vo)
+ { }
+ void do_oop(narrowOop *p) { do_oop_work(p); }
+ void do_oop( oop *p) { do_oop_work(p); }
+
+ template <class T> void do_oop_work(T *p) {
+ oop obj = oopDesc::load_decode_heap_oop(p);
+ guarantee(obj == NULL || !_g1h->is_obj_dead_cond(obj, _vo),
+ "Dead object referenced by a not dead object");
+ }
+};
+
+class VerifyObjsInRegionClosure: public ObjectClosure {
+private:
+ G1CollectedHeap* _g1h;
+ size_t _live_bytes;
+ HeapRegion *_hr;
+ VerifyOption _vo;
+public:
+ // _vo == UsePrevMarking -> use "prev" marking information,
+ // _vo == UseNextMarking -> use "next" marking information,
+ // _vo == UseMarkWord -> use mark word from object header.
+ VerifyObjsInRegionClosure(HeapRegion *hr, VerifyOption vo)
+ : _live_bytes(0), _hr(hr), _vo(vo) {
+ _g1h = G1CollectedHeap::heap();
+ }
+ void do_object(oop o) {
+ VerifyLivenessOopClosure isLive(_g1h, _vo);
+ assert(o != NULL, "Huh?");
+ if (!_g1h->is_obj_dead_cond(o, _vo)) {
+ // If the object is alive according to the mark word,
+ // then verify that the marking information agrees.
+ // Note we can't verify the contra-positive of the
+ // above: if the object is dead (according to the mark
+ // word), it may not be marked, or may have been marked
+ // but has since became dead, or may have been allocated
+ // since the last marking.
+ if (_vo == VerifyOption_G1UseMarkWord) {
+ guarantee(!_g1h->is_obj_dead(o), "mark word and concurrent mark mismatch");
+ }
+
+ o->oop_iterate_no_header(&isLive);
+ if (!_hr->obj_allocated_since_prev_marking(o)) {
+ size_t obj_size = o->size(); // Make sure we don't overflow
+ _live_bytes += (obj_size * HeapWordSize);
+ }
+ }
+ }
+ size_t live_bytes() { return _live_bytes; }
+};
+
+class VerifyRegionClosure: public HeapRegionClosure {
+private:
+ bool _par;
+ VerifyOption _vo;
+ bool _failures;
+public:
+ // _vo == UsePrevMarking -> use "prev" marking information,
+ // _vo == UseNextMarking -> use "next" marking information,
+ // _vo == UseMarkWord -> use mark word from object header.
+ VerifyRegionClosure(bool par, VerifyOption vo)
+ : _par(par),
+ _vo(vo),
+ _failures(false) {}
+
+ bool failures() {
+ return _failures;
+ }
+
+ bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_continues_humongous()) {
+ bool failures = false;
+ r->verify(_vo, &failures);
+ if (failures) {
+ _failures = true;
+ } else {
+ VerifyObjsInRegionClosure not_dead_yet_cl(r, _vo);
+ r->object_iterate(¬_dead_yet_cl);
+ if (_vo != VerifyOption_G1UseNextMarking) {
+ if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {
+ gclog_or_tty->print_cr("["PTR_FORMAT","PTR_FORMAT"] "
+ "max_live_bytes "SIZE_FORMAT" "
+ "< calculated "SIZE_FORMAT,
+ p2i(r->bottom()), p2i(r->end()),
+ r->max_live_bytes(),
+ not_dead_yet_cl.live_bytes());
+ _failures = true;
+ }
+ } else {
+ // When vo == UseNextMarking we cannot currently do a sanity
+ // check on the live bytes as the calculation has not been
+ // finalized yet.
+ }
+ }
+ }
+ return false; // stop the region iteration if we hit a failure
+ }
+};
+
+// This is the task used for parallel verification of the heap regions
+
+class G1ParVerifyTask: public AbstractGangTask {
+private:
+ G1CollectedHeap* _g1h;
+ VerifyOption _vo;
+ bool _failures;
+ HeapRegionClaimer _hrclaimer;
+
+public:
+ // _vo == UsePrevMarking -> use "prev" marking information,
+ // _vo == UseNextMarking -> use "next" marking information,
+ // _vo == UseMarkWord -> use mark word from object header.
+ G1ParVerifyTask(G1CollectedHeap* g1h, VerifyOption vo) :
+ AbstractGangTask("Parallel verify task"),
+ _g1h(g1h),
+ _vo(vo),
+ _failures(false),
+ _hrclaimer(g1h->workers()->active_workers()) {}
+
+ bool failures() {
+ return _failures;
+ }
+
+ void work(uint worker_id) {
+ HandleMark hm;
+ VerifyRegionClosure blk(true, _vo);
+ _g1h->heap_region_par_iterate(&blk, worker_id, &_hrclaimer);
+ if (blk.failures()) {
+ _failures = true;
+ }
+ }
+};
+
+void G1CollectedHeap::verify(bool silent, VerifyOption vo) {
+ if (SafepointSynchronize::is_at_safepoint()) {
+ assert(Thread::current()->is_VM_thread(),
+ "Expected to be executed serially by the VM thread at this point");
+
+ if (!silent) { gclog_or_tty->print("Roots "); }
+ VerifyRootsClosure rootsCl(vo);
+ VerifyKlassClosure klassCl(this, &rootsCl);
+ CLDToKlassAndOopClosure cldCl(&klassCl, &rootsCl, false);
+
+ // We apply the relevant closures to all the oops in the
+ // system dictionary, class loader data graph, the string table
+ // and the nmethods in the code cache.
+ G1VerifyCodeRootOopClosure codeRootsCl(this, &rootsCl, vo);
+ G1VerifyCodeRootBlobClosure blobsCl(&codeRootsCl);
+
+ {
+ G1RootProcessor root_processor(this);
+ root_processor.process_all_roots(&rootsCl,
+ &cldCl,
+ &blobsCl);
+ }
+
+ bool failures = rootsCl.failures() || codeRootsCl.failures();
+
+ if (vo != VerifyOption_G1UseMarkWord) {
+ // If we're verifying during a full GC then the region sets
+ // will have been torn down at the start of the GC. Therefore
+ // verifying the region sets will fail. So we only verify
+ // the region sets when not in a full GC.
+ if (!silent) { gclog_or_tty->print("HeapRegionSets "); }
+ verify_region_sets();
+ }
+
+ if (!silent) { gclog_or_tty->print("HeapRegions "); }
+ if (GCParallelVerificationEnabled && ParallelGCThreads > 1) {
+
+ G1ParVerifyTask task(this, vo);
+ assert(UseDynamicNumberOfGCThreads ||
+ workers()->active_workers() == workers()->total_workers(),
+ "If not dynamic should be using all the workers");
+ uint n_workers = workers()->active_workers();
+ set_par_threads(n_workers);
+ workers()->run_task(&task);
+ set_par_threads(0);
+ if (task.failures()) {
+ failures = true;
+ }
+
+ } else {
+ VerifyRegionClosure blk(false, vo);
+ heap_region_iterate(&blk);
+ if (blk.failures()) {
+ failures = true;
+ }
+ }
+
+ if (G1StringDedup::is_enabled()) {
+ if (!silent) gclog_or_tty->print("StrDedup ");
+ G1StringDedup::verify();
+ }
+
+ if (failures) {
+ gclog_or_tty->print_cr("Heap:");
+ // It helps to have the per-region information in the output to
+ // help us track down what went wrong. This is why we call
+ // print_extended_on() instead of print_on().
+ print_extended_on(gclog_or_tty);
+ gclog_or_tty->cr();
+ gclog_or_tty->flush();
+ }
+ guarantee(!failures, "there should not have been any failures");
+ } else {
+ if (!silent) {
+ gclog_or_tty->print("(SKIPPING Roots, HeapRegionSets, HeapRegions, RemSet");
+ if (G1StringDedup::is_enabled()) {
+ gclog_or_tty->print(", StrDedup");
+ }
+ gclog_or_tty->print(") ");
+ }
+ }
+}
+
+void G1CollectedHeap::verify(bool silent) {
+ verify(silent, VerifyOption_G1UsePrevMarking);
+}
+
+double G1CollectedHeap::verify(bool guard, const char* msg) {
+ double verify_time_ms = 0.0;
+
+ if (guard && total_collections() >= VerifyGCStartAt) {
+ double verify_start = os::elapsedTime();
+ HandleMark hm; // Discard invalid handles created during verification
+ prepare_for_verify();
+ Universe::verify(VerifyOption_G1UsePrevMarking, msg);
+ verify_time_ms = (os::elapsedTime() - verify_start) * 1000;
+ }
+
+ return verify_time_ms;
+}
+
+void G1CollectedHeap::verify_before_gc() {
+ double verify_time_ms = verify(VerifyBeforeGC, " VerifyBeforeGC:");
+ g1_policy()->phase_times()->record_verify_before_time_ms(verify_time_ms);
+}
+
+void G1CollectedHeap::verify_after_gc() {
+ double verify_time_ms = verify(VerifyAfterGC, " VerifyAfterGC:");
+ g1_policy()->phase_times()->record_verify_after_time_ms(verify_time_ms);
+}
+
+class PrintRegionClosure: public HeapRegionClosure {
+ outputStream* _st;
+public:
+ PrintRegionClosure(outputStream* st) : _st(st) {}
+ bool doHeapRegion(HeapRegion* r) {
+ r->print_on(_st);
+ return false;
+ }
+};
+
+bool G1CollectedHeap::is_obj_dead_cond(const oop obj,
+ const HeapRegion* hr,
+ const VerifyOption vo) const {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj, hr);
+ case VerifyOption_G1UseNextMarking: return is_obj_ill(obj, hr);
+ case VerifyOption_G1UseMarkWord: return !obj->is_gc_marked();
+ default: ShouldNotReachHere();
+ }
+ return false; // keep some compilers happy
+}
+
+bool G1CollectedHeap::is_obj_dead_cond(const oop obj,
+ const VerifyOption vo) const {
+ switch (vo) {
+ case VerifyOption_G1UsePrevMarking: return is_obj_dead(obj);
+ case VerifyOption_G1UseNextMarking: return is_obj_ill(obj);
+ case VerifyOption_G1UseMarkWord: return !obj->is_gc_marked();
+ default: ShouldNotReachHere();
+ }
+ return false; // keep some compilers happy
+}
+
+void G1CollectedHeap::print_on(outputStream* st) const {
+ st->print(" %-20s", "garbage-first heap");
+ st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
+ capacity()/K, used_unlocked()/K);
+ st->print(" [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ")",
+ p2i(_hrm.reserved().start()),
+ p2i(_hrm.reserved().start() + _hrm.length() + HeapRegion::GrainWords),
+ p2i(_hrm.reserved().end()));
+ st->cr();
+ st->print(" region size " SIZE_FORMAT "K, ", HeapRegion::GrainBytes / K);
+ uint young_regions = _young_list->length();
+ st->print("%u young (" SIZE_FORMAT "K), ", young_regions,
+ (size_t) young_regions * HeapRegion::GrainBytes / K);
+ uint survivor_regions = g1_policy()->recorded_survivor_regions();
+ st->print("%u survivors (" SIZE_FORMAT "K)", survivor_regions,
+ (size_t) survivor_regions * HeapRegion::GrainBytes / K);
+ st->cr();
+ MetaspaceAux::print_on(st);
+}
+
+void G1CollectedHeap::print_extended_on(outputStream* st) const {
+ print_on(st);
+
+ // Print the per-region information.
+ st->cr();
+ st->print_cr("Heap Regions: (Y=young(eden), SU=young(survivor), "
+ "HS=humongous(starts), HC=humongous(continues), "
+ "CS=collection set, F=free, TS=gc time stamp, "
+ "PTAMS=previous top-at-mark-start, "
+ "NTAMS=next top-at-mark-start)");
+ PrintRegionClosure blk(st);
+ heap_region_iterate(&blk);
+}
+
+void G1CollectedHeap::print_on_error(outputStream* st) const {
+ this->CollectedHeap::print_on_error(st);
+
+ if (_cm != NULL) {
+ st->cr();
+ _cm->print_on_error(st);
+ }
+}
+
+void G1CollectedHeap::print_gc_threads_on(outputStream* st) const {
+ workers()->print_worker_threads_on(st);
+ _cmThread->print_on(st);
+ st->cr();
+ _cm->print_worker_threads_on(st);
+ _cg1r->print_worker_threads_on(st);
+ if (G1StringDedup::is_enabled()) {
+ G1StringDedup::print_worker_threads_on(st);
+ }
+}
+
+void G1CollectedHeap::gc_threads_do(ThreadClosure* tc) const {
+ workers()->threads_do(tc);
+ tc->do_thread(_cmThread);
+ _cg1r->threads_do(tc);
+ if (G1StringDedup::is_enabled()) {
+ G1StringDedup::threads_do(tc);
+ }
+}
+
+void G1CollectedHeap::print_tracing_info() const {
+ // We'll overload this to mean "trace GC pause statistics."
+ if (TraceYoungGenTime || TraceOldGenTime) {
+ // The "G1CollectorPolicy" is keeping track of these stats, so delegate
+ // to that.
+ g1_policy()->print_tracing_info();
+ }
+ if (G1SummarizeRSetStats) {
+ g1_rem_set()->print_summary_info();
+ }
+ if (G1SummarizeConcMark) {
+ concurrent_mark()->print_summary_info();
+ }
+ g1_policy()->print_yg_surv_rate_info();
+}
+
+#ifndef PRODUCT
+// Helpful for debugging RSet issues.
+
+class PrintRSetsClosure : public HeapRegionClosure {
+private:
+ const char* _msg;
+ size_t _occupied_sum;
+
+public:
+ bool doHeapRegion(HeapRegion* r) {
+ HeapRegionRemSet* hrrs = r->rem_set();
+ size_t occupied = hrrs->occupied();
+ _occupied_sum += occupied;
+
+ gclog_or_tty->print_cr("Printing RSet for region "HR_FORMAT,
+ HR_FORMAT_PARAMS(r));
+ if (occupied == 0) {
+ gclog_or_tty->print_cr(" RSet is empty");
+ } else {
+ hrrs->print();
+ }
+ gclog_or_tty->print_cr("----------");
+ return false;
+ }
+
+ PrintRSetsClosure(const char* msg) : _msg(msg), _occupied_sum(0) {
+ gclog_or_tty->cr();
+ gclog_or_tty->print_cr("========================================");
+ gclog_or_tty->print_cr("%s", msg);
+ gclog_or_tty->cr();
+ }
+
+ ~PrintRSetsClosure() {
+ gclog_or_tty->print_cr("Occupied Sum: "SIZE_FORMAT, _occupied_sum);
+ gclog_or_tty->print_cr("========================================");
+ gclog_or_tty->cr();
+ }
+};
+
+void G1CollectedHeap::print_cset_rsets() {
+ PrintRSetsClosure cl("Printing CSet RSets");
+ collection_set_iterate(&cl);
+}
+
+void G1CollectedHeap::print_all_rsets() {
+ PrintRSetsClosure cl("Printing All RSets");;
+ heap_region_iterate(&cl);
+}
+#endif // PRODUCT
+
+G1CollectedHeap* G1CollectedHeap::heap() {
+ CollectedHeap* heap = Universe::heap();
+ assert(heap != NULL, "Uninitialized access to G1CollectedHeap::heap()");
+ assert(heap->kind() == CollectedHeap::G1CollectedHeap, "Not a G1CollectedHeap");
+ return (G1CollectedHeap*)heap;
+}
+
+void G1CollectedHeap::gc_prologue(bool full /* Ignored */) {
+ // always_do_update_barrier = false;
+ assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
+ // Fill TLAB's and such
+ accumulate_statistics_all_tlabs();
+ ensure_parsability(true);
+
+ if (G1SummarizeRSetStats && (G1SummarizeRSetStatsPeriod > 0) &&
+ (total_collections() % G1SummarizeRSetStatsPeriod == 0)) {
+ g1_rem_set()->print_periodic_summary_info("Before GC RS summary");
+ }
+}
+
+void G1CollectedHeap::gc_epilogue(bool full) {
+
+ if (G1SummarizeRSetStats &&
+ (G1SummarizeRSetStatsPeriod > 0) &&
+ // we are at the end of the GC. Total collections has already been increased.
+ ((total_collections() - 1) % G1SummarizeRSetStatsPeriod == 0)) {
+ g1_rem_set()->print_periodic_summary_info("After GC RS summary");
+ }
+
+ // FIXME: what is this about?
+ // I'm ignoring the "fill_newgen()" call if "alloc_event_enabled"
+ // is set.
+ COMPILER2_PRESENT(assert(DerivedPointerTable::is_empty(),
+ "derived pointer present"));
+ // always_do_update_barrier = true;
+
+ resize_all_tlabs();
+ allocation_context_stats().update(full);
+
+ // We have just completed a GC. Update the soft reference
+ // policy with the new heap occupancy
+ Universe::update_heap_info_at_gc();
+}
+
+HeapWord* G1CollectedHeap::do_collection_pause(size_t word_size,
+ uint gc_count_before,
+ bool* succeeded,
+ GCCause::Cause gc_cause) {
+ assert_heap_not_locked_and_not_at_safepoint();
+ g1_policy()->record_stop_world_start();
+ VM_G1IncCollectionPause op(gc_count_before,
+ word_size,
+ false, /* should_initiate_conc_mark */
+ g1_policy()->max_pause_time_ms(),
+ gc_cause);
+
+ op.set_allocation_context(AllocationContext::current());
+ VMThread::execute(&op);
+
+ HeapWord* result = op.result();
+ bool ret_succeeded = op.prologue_succeeded() && op.pause_succeeded();
+ assert(result == NULL || ret_succeeded,
+ "the result should be NULL if the VM did not succeed");
+ *succeeded = ret_succeeded;
+
+ assert_heap_not_locked();
+ return result;
+}
+
+void
+G1CollectedHeap::doConcurrentMark() {
+ MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
+ if (!_cmThread->in_progress()) {
+ _cmThread->set_started();
+ CGC_lock->notify();
+ }
+}
+
+size_t G1CollectedHeap::pending_card_num() {
+ size_t extra_cards = 0;
+ JavaThread *curr = Threads::first();
+ while (curr != NULL) {
+ DirtyCardQueue& dcq = curr->dirty_card_queue();
+ extra_cards += dcq.size();
+ curr = curr->next();
+ }
+ DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
+ size_t buffer_size = dcqs.buffer_size();
+ size_t buffer_num = dcqs.completed_buffers_num();
+
+ // PtrQueueSet::buffer_size() and PtrQueue:size() return sizes
+ // in bytes - not the number of 'entries'. We need to convert
+ // into a number of cards.
+ return (buffer_size * buffer_num + extra_cards) / oopSize;
+}
+
+size_t G1CollectedHeap::cards_scanned() {
+ return g1_rem_set()->cardsScanned();
+}
+
+class RegisterHumongousWithInCSetFastTestClosure : public HeapRegionClosure {
+ private:
+ size_t _total_humongous;
+ size_t _candidate_humongous;
+
+ DirtyCardQueue _dcq;
+
+ // We don't nominate objects with many remembered set entries, on
+ // the assumption that such objects are likely still live.
+ bool is_remset_small(HeapRegion* region) const {
+ HeapRegionRemSet* const rset = region->rem_set();
+ return G1EagerReclaimHumongousObjectsWithStaleRefs
+ ? rset->occupancy_less_or_equal_than(G1RSetSparseRegionEntries)
+ : rset->is_empty();
+ }
+
+ bool is_typeArray_region(HeapRegion* region) const {
+ return oop(region->bottom())->is_typeArray();
+ }
+
+ bool humongous_region_is_candidate(G1CollectedHeap* heap, HeapRegion* region) const {
+ assert(region->is_starts_humongous(), "Must start a humongous object");
+
+ // Candidate selection must satisfy the following constraints
+ // while concurrent marking is in progress:
+ //
+ // * In order to maintain SATB invariants, an object must not be
+ // reclaimed if it was allocated before the start of marking and
+ // has not had its references scanned. Such an object must have
+ // its references (including type metadata) scanned to ensure no
+ // live objects are missed by the marking process. Objects
+ // allocated after the start of concurrent marking don't need to
+ // be scanned.
+ //
+ // * An object must not be reclaimed if it is on the concurrent
+ // mark stack. Objects allocated after the start of concurrent
+ // marking are never pushed on the mark stack.
+ //
+ // Nominating only objects allocated after the start of concurrent
+ // marking is sufficient to meet both constraints. This may miss
+ // some objects that satisfy the constraints, but the marking data
+ // structures don't support efficiently performing the needed
+ // additional tests or scrubbing of the mark stack.
+ //
+ // However, we presently only nominate is_typeArray() objects.
+ // A humongous object containing references induces remembered
+ // set entries on other regions. In order to reclaim such an
+ // object, those remembered sets would need to be cleaned up.
+ //
+ // We also treat is_typeArray() objects specially, allowing them
+ // to be reclaimed even if allocated before the start of
+ // concurrent mark. For this we rely on mark stack insertion to
+ // exclude is_typeArray() objects, preventing reclaiming an object
+ // that is in the mark stack. We also rely on the metadata for
+ // such objects to be built-in and so ensured to be kept live.
+ // Frequent allocation and drop of large binary blobs is an
+ // important use case for eager reclaim, and this special handling
+ // may reduce needed headroom.
+
+ return is_typeArray_region(region) && is_remset_small(region);
+ }
+
+ public:
+ RegisterHumongousWithInCSetFastTestClosure()
+ : _total_humongous(0),
+ _candidate_humongous(0),
+ _dcq(&JavaThread::dirty_card_queue_set()) {
+ }
+
+ virtual bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_starts_humongous()) {
+ return false;
+ }
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+
+ bool is_candidate = humongous_region_is_candidate(g1h, r);
+ uint rindex = r->hrm_index();
+ g1h->set_humongous_reclaim_candidate(rindex, is_candidate);
+ if (is_candidate) {
+ _candidate_humongous++;
+ g1h->register_humongous_region_with_cset(rindex);
+ // Is_candidate already filters out humongous object with large remembered sets.
+ // If we have a humongous object with a few remembered sets, we simply flush these
+ // remembered set entries into the DCQS. That will result in automatic
+ // re-evaluation of their remembered set entries during the following evacuation
+ // phase.
+ if (!r->rem_set()->is_empty()) {
+ guarantee(r->rem_set()->occupancy_less_or_equal_than(G1RSetSparseRegionEntries),
+ "Found a not-small remembered set here. This is inconsistent with previous assumptions.");
+ G1SATBCardTableLoggingModRefBS* bs = g1h->g1_barrier_set();
+ HeapRegionRemSetIterator hrrs(r->rem_set());
+ size_t card_index;
+ while (hrrs.has_next(card_index)) {
+ jbyte* card_ptr = (jbyte*)bs->byte_for_index(card_index);
+ // The remembered set might contain references to already freed
+ // regions. Filter out such entries to avoid failing card table
+ // verification.
+ if (!g1h->heap_region_containing(bs->addr_for(card_ptr))->is_free()) {
+ if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
+ *card_ptr = CardTableModRefBS::dirty_card_val();
+ _dcq.enqueue(card_ptr);
+ }
+ }
+ }
+ r->rem_set()->clear_locked();
+ }
+ assert(r->rem_set()->is_empty(), "At this point any humongous candidate remembered set must be empty.");
+ }
+ _total_humongous++;
+
+ return false;
+ }
+
+ size_t total_humongous() const { return _total_humongous; }
+ size_t candidate_humongous() const { return _candidate_humongous; }
+
+ void flush_rem_set_entries() { _dcq.flush(); }
+};
+
+void G1CollectedHeap::register_humongous_regions_with_cset() {
+ if (!G1EagerReclaimHumongousObjects) {
+ g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(0.0, 0, 0);
+ return;
+ }
+ double time = os::elapsed_counter();
+
+ // Collect reclaim candidate information and register candidates with cset.
+ RegisterHumongousWithInCSetFastTestClosure cl;
+ heap_region_iterate(&cl);
+
+ time = ((double)(os::elapsed_counter() - time) / os::elapsed_frequency()) * 1000.0;
+ g1_policy()->phase_times()->record_fast_reclaim_humongous_stats(time,
+ cl.total_humongous(),
+ cl.candidate_humongous());
+ _has_humongous_reclaim_candidates = cl.candidate_humongous() > 0;
+
+ // Finally flush all remembered set entries to re-check into the global DCQS.
+ cl.flush_rem_set_entries();
+}
+
+void
+G1CollectedHeap::setup_surviving_young_words() {
+ assert(_surviving_young_words == NULL, "pre-condition");
+ uint array_length = g1_policy()->young_cset_region_length();
+ _surviving_young_words = NEW_C_HEAP_ARRAY(size_t, (size_t) array_length, mtGC);
+ if (_surviving_young_words == NULL) {
+ vm_exit_out_of_memory(sizeof(size_t) * array_length, OOM_MALLOC_ERROR,
+ "Not enough space for young surv words summary.");
+ }
+ memset(_surviving_young_words, 0, (size_t) array_length * sizeof(size_t));
+#ifdef ASSERT
+ for (uint i = 0; i < array_length; ++i) {
+ assert( _surviving_young_words[i] == 0, "memset above" );
+ }
+#endif // !ASSERT
+}
+
+void
+G1CollectedHeap::update_surviving_young_words(size_t* surv_young_words) {
+ MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
+ uint array_length = g1_policy()->young_cset_region_length();
+ for (uint i = 0; i < array_length; ++i) {
+ _surviving_young_words[i] += surv_young_words[i];
+ }
+}
+
+void
+G1CollectedHeap::cleanup_surviving_young_words() {
+ guarantee( _surviving_young_words != NULL, "pre-condition" );
+ FREE_C_HEAP_ARRAY(size_t, _surviving_young_words);
+ _surviving_young_words = NULL;
+}
+
+#ifdef ASSERT
+class VerifyCSetClosure: public HeapRegionClosure {
+public:
+ bool doHeapRegion(HeapRegion* hr) {
+ // Here we check that the CSet region's RSet is ready for parallel
+ // iteration. The fields that we'll verify are only manipulated
+ // when the region is part of a CSet and is collected. Afterwards,
+ // we reset these fields when we clear the region's RSet (when the
+ // region is freed) so they are ready when the region is
+ // re-allocated. The only exception to this is if there's an
+ // evacuation failure and instead of freeing the region we leave
+ // it in the heap. In that case, we reset these fields during
+ // evacuation failure handling.
+ guarantee(hr->rem_set()->verify_ready_for_par_iteration(), "verification");
+
+ // Here's a good place to add any other checks we'd like to
+ // perform on CSet regions.
+ return false;
+ }
+};
+#endif // ASSERT
+
+#if TASKQUEUE_STATS
+void G1CollectedHeap::print_taskqueue_stats_hdr(outputStream* const st) {
+ st->print_raw_cr("GC Task Stats");
+ st->print_raw("thr "); TaskQueueStats::print_header(1, st); st->cr();
+ st->print_raw("--- "); TaskQueueStats::print_header(2, st); st->cr();
+}
+
+void G1CollectedHeap::print_taskqueue_stats(outputStream* const st) const {
+ print_taskqueue_stats_hdr(st);
+
+ TaskQueueStats totals;
+ const uint n = workers()->total_workers();
+ for (uint i = 0; i < n; ++i) {
+ st->print("%3u ", i); task_queue(i)->stats.print(st); st->cr();
+ totals += task_queue(i)->stats;
+ }
+ st->print_raw("tot "); totals.print(st); st->cr();
+
+ DEBUG_ONLY(totals.verify());
+}
+
+void G1CollectedHeap::reset_taskqueue_stats() {
+ const uint n = workers()->total_workers();
+ for (uint i = 0; i < n; ++i) {
+ task_queue(i)->stats.reset();
+ }
+}
+#endif // TASKQUEUE_STATS
+
+void G1CollectedHeap::log_gc_header() {
+ if (!G1Log::fine()) {
+ return;
+ }
+
+ gclog_or_tty->gclog_stamp(_gc_tracer_stw->gc_id());
+
+ GCCauseString gc_cause_str = GCCauseString("GC pause", gc_cause())
+ .append(g1_policy()->gcs_are_young() ? "(young)" : "(mixed)")
+ .append(g1_policy()->during_initial_mark_pause() ? " (initial-mark)" : "");
+
+ gclog_or_tty->print("[%s", (const char*)gc_cause_str);
+}
+
+void G1CollectedHeap::log_gc_footer(double pause_time_sec) {
+ if (!G1Log::fine()) {
+ return;
+ }
+
+ if (G1Log::finer()) {
+ if (evacuation_failed()) {
+ gclog_or_tty->print(" (to-space exhausted)");
+ }
+ gclog_or_tty->print_cr(", %3.7f secs]", pause_time_sec);
+ g1_policy()->phase_times()->note_gc_end();
+ g1_policy()->phase_times()->print(pause_time_sec);
+ g1_policy()->print_detailed_heap_transition();
+ } else {
+ if (evacuation_failed()) {
+ gclog_or_tty->print("--");
+ }
+ g1_policy()->print_heap_transition();
+ gclog_or_tty->print_cr(", %3.7f secs]", pause_time_sec);
+ }
+ gclog_or_tty->flush();
+}
+
+bool
+G1CollectedHeap::do_collection_pause_at_safepoint(double target_pause_time_ms) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+ guarantee(!is_gc_active(), "collection is not reentrant");
+
+ if (GC_locker::check_active_before_gc()) {
+ return false;
+ }
+
+ _gc_timer_stw->register_gc_start();
+
+ _gc_tracer_stw->report_gc_start(gc_cause(), _gc_timer_stw->gc_start());
+
+ SvcGCMarker sgcm(SvcGCMarker::MINOR);
+ ResourceMark rm;
+
+ G1Log::update_level();
+ print_heap_before_gc();
+ trace_heap_before_gc(_gc_tracer_stw);
+
+ verify_region_sets_optional();
+ verify_dirty_young_regions();
+
+ // This call will decide whether this pause is an initial-mark
+ // pause. If it is, during_initial_mark_pause() will return true
+ // for the duration of this pause.
+ g1_policy()->decide_on_conc_mark_initiation();
+
+ // We do not allow initial-mark to be piggy-backed on a mixed GC.
+ assert(!g1_policy()->during_initial_mark_pause() ||
+ g1_policy()->gcs_are_young(), "sanity");
+
+ // We also do not allow mixed GCs during marking.
+ assert(!mark_in_progress() || g1_policy()->gcs_are_young(), "sanity");
+
+ // Record whether this pause is an initial mark. When the current
+ // thread has completed its logging output and it's safe to signal
+ // the CM thread, the flag's value in the policy has been reset.
+ bool should_start_conc_mark = g1_policy()->during_initial_mark_pause();
+
+ // Inner scope for scope based logging, timers, and stats collection
+ {
+ EvacuationInfo evacuation_info;
+
+ if (g1_policy()->during_initial_mark_pause()) {
+ // We are about to start a marking cycle, so we increment the
+ // full collection counter.
+ increment_old_marking_cycles_started();
+ register_concurrent_cycle_start(_gc_timer_stw->gc_start());
+ }
+
+ _gc_tracer_stw->report_yc_type(yc_type());
+
+ TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
+
+ uint active_workers = AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(),
+ workers()->active_workers(),
+ Threads::number_of_non_daemon_threads());
+ assert(UseDynamicNumberOfGCThreads ||
+ active_workers == workers()->total_workers(),
+ "If not dynamic should be using all the workers");
+ workers()->set_active_workers(active_workers);
+
+ double pause_start_sec = os::elapsedTime();
+ g1_policy()->phase_times()->note_gc_start(active_workers, mark_in_progress());
+ log_gc_header();
+
+ TraceCollectorStats tcs(g1mm()->incremental_collection_counters());
+ TraceMemoryManagerStats tms(false /* fullGC */, gc_cause());
+
+ // If the secondary_free_list is not empty, append it to the
+ // free_list. No need to wait for the cleanup operation to finish;
+ // the region allocation code will check the secondary_free_list
+ // and wait if necessary. If the G1StressConcRegionFreeing flag is
+ // set, skip this step so that the region allocation code has to
+ // get entries from the secondary_free_list.
+ if (!G1StressConcRegionFreeing) {
+ append_secondary_free_list_if_not_empty_with_lock();
+ }
+
+ assert(check_young_list_well_formed(), "young list should be well formed");
+
+ // 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,
+ // it will be set.
+
+ { // Call to jvmpi::post_class_unload_events must occur outside of active GC
+ IsGCActiveMark x;
+
+ gc_prologue(false);
+ increment_total_collections(false /* full gc */);
+ increment_gc_time_stamp();
+
+ verify_before_gc();
+
+ check_bitmaps("GC Start");
+
+ COMPILER2_PRESENT(DerivedPointerTable::clear());
+
+ // Please see comment in g1CollectedHeap.hpp and
+ // G1CollectedHeap::ref_processing_init() to see how
+ // reference processing currently works in G1.
+
+ // Enable discovery in the STW reference processor
+ ref_processor_stw()->enable_discovery();
+
+ {
+ // We want to temporarily turn off discovery by the
+ // CM ref processor, if necessary, and turn it back on
+ // on again later if we do. Using a scoped
+ // NoRefDiscovery object will do this.
+ NoRefDiscovery no_cm_discovery(ref_processor_cm());
+
+ // Forget the current alloc region (we might even choose it to be part
+ // of the collection set!).
+ _allocator->release_mutator_alloc_region();
+
+ // We should call this after we retire the mutator alloc
+ // region(s) so that all the ALLOC / RETIRE events are generated
+ // before the start GC event.
+ _hr_printer.start_gc(false /* full */, (size_t) total_collections());
+
+ // This timing is only used by the ergonomics to handle our pause target.
+ // It is unclear why this should not include the full pause. We will
+ // investigate this in CR 7178365.
+ //
+ // Preserving the old comment here if that helps the investigation:
+ //
+ // The elapsed time induced by the start time below deliberately elides
+ // the possible verification above.
+ double sample_start_time_sec = os::elapsedTime();
+
+#if YOUNG_LIST_VERBOSE
+ gclog_or_tty->print_cr("\nBefore recording pause start.\nYoung_list:");
+ _young_list->print();
+ g1_policy()->print_collection_set(g1_policy()->inc_cset_head(), gclog_or_tty);
+#endif // YOUNG_LIST_VERBOSE
+
+ g1_policy()->record_collection_pause_start(sample_start_time_sec);
+
+ double scan_wait_start = os::elapsedTime();
+ // We have to wait until the CM threads finish scanning the
+ // root regions as it's the only way to ensure that all the
+ // objects on them have been correctly scanned before we start
+ // moving them during the GC.
+ bool waited = _cm->root_regions()->wait_until_scan_finished();
+ double wait_time_ms = 0.0;
+ if (waited) {
+ double scan_wait_end = os::elapsedTime();
+ wait_time_ms = (scan_wait_end - scan_wait_start) * 1000.0;
+ }
+ g1_policy()->phase_times()->record_root_region_scan_wait_time(wait_time_ms);
+
+#if YOUNG_LIST_VERBOSE
+ gclog_or_tty->print_cr("\nAfter recording pause start.\nYoung_list:");
+ _young_list->print();
+#endif // YOUNG_LIST_VERBOSE
+
+ if (g1_policy()->during_initial_mark_pause()) {
+ concurrent_mark()->checkpointRootsInitialPre();
+ }
+
+#if YOUNG_LIST_VERBOSE
+ gclog_or_tty->print_cr("\nBefore choosing collection set.\nYoung_list:");
+ _young_list->print();
+ g1_policy()->print_collection_set(g1_policy()->inc_cset_head(), gclog_or_tty);
+#endif // YOUNG_LIST_VERBOSE
+
+ g1_policy()->finalize_cset(target_pause_time_ms, evacuation_info);
+
+ register_humongous_regions_with_cset();
+
+ assert(check_cset_fast_test(), "Inconsistency in the InCSetState table.");
+
+ _cm->note_start_of_gc();
+ // We call this after finalize_cset() to
+ // ensure that the CSet has been finalized.
+ _cm->verify_no_cset_oops();
+
+ if (_hr_printer.is_active()) {
+ HeapRegion* hr = g1_policy()->collection_set();
+ while (hr != NULL) {
+ _hr_printer.cset(hr);
+ hr = hr->next_in_collection_set();
+ }
+ }
+
+#ifdef ASSERT
+ VerifyCSetClosure cl;
+ collection_set_iterate(&cl);
+#endif // ASSERT
+
+ setup_surviving_young_words();
+
+ // Initialize the GC alloc regions.
+ _allocator->init_gc_alloc_regions(evacuation_info);
+
+ // Actually do the work...
+ evacuate_collection_set(evacuation_info);
+
+ free_collection_set(g1_policy()->collection_set(), evacuation_info);
+
+ eagerly_reclaim_humongous_regions();
+
+ g1_policy()->clear_collection_set();
+
+ cleanup_surviving_young_words();
+
+ // Start a new incremental collection set for the next pause.
+ g1_policy()->start_incremental_cset_building();
+
+ clear_cset_fast_test();
+
+ _young_list->reset_sampled_info();
+
+ // Don't check the whole heap at this point as the
+ // GC alloc regions from this pause have been tagged
+ // as survivors and moved on to the survivor list.
+ // Survivor regions will fail the !is_young() check.
+ assert(check_young_list_empty(false /* check_heap */),
+ "young list should be empty");
+
+#if YOUNG_LIST_VERBOSE
+ gclog_or_tty->print_cr("Before recording survivors.\nYoung List:");
+ _young_list->print();
+#endif // YOUNG_LIST_VERBOSE
+
+ g1_policy()->record_survivor_regions(_young_list->survivor_length(),
+ _young_list->first_survivor_region(),
+ _young_list->last_survivor_region());
+
+ _young_list->reset_auxilary_lists();
+
+ if (evacuation_failed()) {
+ _allocator->set_used(recalculate_used());
+ uint n_queues = MAX2((int)ParallelGCThreads, 1);
+ for (uint i = 0; i < n_queues; i++) {
+ if (_evacuation_failed_info_array[i].has_failed()) {
+ _gc_tracer_stw->report_evacuation_failed(_evacuation_failed_info_array[i]);
+ }
+ }
+ } else {
+ // The "used" of the the collection set have already been subtracted
+ // when they were freed. Add in the bytes evacuated.
+ _allocator->increase_used(g1_policy()->bytes_copied_during_gc());
+ }
+
+ if (g1_policy()->during_initial_mark_pause()) {
+ // We have to do this before we notify the CM threads that
+ // they can start working to make sure that all the
+ // appropriate initialization is done on the CM object.
+ concurrent_mark()->checkpointRootsInitialPost();
+ set_marking_started();
+ // Note that we don't actually trigger the CM thread at
+ // this point. We do that later when we're sure that
+ // the current thread has completed its logging output.
+ }
+
+ allocate_dummy_regions();
+
+#if YOUNG_LIST_VERBOSE
+ gclog_or_tty->print_cr("\nEnd of the pause.\nYoung_list:");
+ _young_list->print();
+ g1_policy()->print_collection_set(g1_policy()->inc_cset_head(), gclog_or_tty);
+#endif // YOUNG_LIST_VERBOSE
+
+ _allocator->init_mutator_alloc_region();
+
+ {
+ size_t expand_bytes = g1_policy()->expansion_amount();
+ if (expand_bytes > 0) {
+ size_t bytes_before = capacity();
+ // No need for an ergo verbose message here,
+ // expansion_amount() does this when it returns a value > 0.
+ if (!expand(expand_bytes)) {
+ // We failed to expand the heap. Cannot do anything about it.
+ }
+ }
+ }
+
+ // We redo the verification but now wrt to the new CSet which
+ // has just got initialized after the previous CSet was freed.
+ _cm->verify_no_cset_oops();
+ _cm->note_end_of_gc();
+
+ // This timing is only used by the ergonomics to handle our pause target.
+ // It is unclear why this should not include the full pause. We will
+ // investigate this in CR 7178365.
+ double sample_end_time_sec = os::elapsedTime();
+ double pause_time_ms = (sample_end_time_sec - sample_start_time_sec) * MILLIUNITS;
+ g1_policy()->record_collection_pause_end(pause_time_ms, evacuation_info);
+
+ MemoryService::track_memory_usage();
+
+ // In prepare_for_verify() below we'll need to scan the deferred
+ // update buffers to bring the RSets up-to-date if
+ // G1HRRSFlushLogBuffersOnVerify has been set. While scanning
+ // the update buffers we'll probably need to scan cards on the
+ // regions we just allocated to (i.e., the GC alloc
+ // regions). However, during the last GC we called
+ // set_saved_mark() on all the GC alloc regions, so card
+ // scanning might skip the [saved_mark_word()...top()] area of
+ // those regions (i.e., the area we allocated objects into
+ // during the last GC). But it shouldn't. Given that
+ // saved_mark_word() is conditional on whether the GC time stamp
+ // on the region is current or not, by incrementing the GC time
+ // stamp here we invalidate all the GC time stamps on all the
+ // regions and saved_mark_word() will simply return top() for
+ // all the regions. This is a nicer way of ensuring this rather
+ // than iterating over the regions and fixing them. In fact, the
+ // GC time stamp increment here also ensures that
+ // saved_mark_word() will return top() between pauses, i.e.,
+ // during concurrent refinement. So we don't need the
+ // is_gc_active() check to decided which top to use when
+ // scanning cards (see CR 7039627).
+ increment_gc_time_stamp();
+
+ verify_after_gc();
+ check_bitmaps("GC End");
+
+ assert(!ref_processor_stw()->discovery_enabled(), "Postcondition");
+ ref_processor_stw()->verify_no_references_recorded();
+
+ // CM reference discovery will be re-enabled if necessary.
+ }
+
+ // We should do this after we potentially expand the heap so
+ // that all the COMMIT events are generated before the end GC
+ // event, and after we retire the GC alloc regions so that all
+ // RETIRE events are generated before the end GC event.
+ _hr_printer.end_gc(false /* full */, (size_t) total_collections());
+
+#ifdef TRACESPINNING
+ ParallelTaskTerminator::print_termination_counts();
+#endif
+
+ gc_epilogue(false);
+ }
+
+ // Print the remainder of the GC log output.
+ log_gc_footer(os::elapsedTime() - pause_start_sec);
+
+ // It is not yet to safe to tell the concurrent mark to
+ // start as we have some optional output below. We don't want the
+ // output from the concurrent mark thread interfering with this
+ // logging output either.
+
+ _hrm.verify_optional();
+ verify_region_sets_optional();
+
+ TASKQUEUE_STATS_ONLY(if (PrintTaskqueue) print_taskqueue_stats());
+ TASKQUEUE_STATS_ONLY(reset_taskqueue_stats());
+
+ print_heap_after_gc();
+ trace_heap_after_gc(_gc_tracer_stw);
+
+ // We must call G1MonitoringSupport::update_sizes() in the same scoping level
+ // as an active TraceMemoryManagerStats object (i.e. before the destructor for the
+ // TraceMemoryManagerStats is called) so that the G1 memory pools are updated
+ // before any GC notifications are raised.
+ g1mm()->update_sizes();
+
+ _gc_tracer_stw->report_evacuation_info(&evacuation_info);
+ _gc_tracer_stw->report_tenuring_threshold(_g1_policy->tenuring_threshold());
+ _gc_timer_stw->register_gc_end();
+ _gc_tracer_stw->report_gc_end(_gc_timer_stw->gc_end(), _gc_timer_stw->time_partitions());
+ }
+ // It should now be safe to tell the concurrent mark thread to start
+ // without its logging output interfering with the logging output
+ // that came from the pause.
+
+ if (should_start_conc_mark) {
+ // CAUTION: after the doConcurrentMark() call below,
+ // the concurrent marking thread(s) could be running
+ // concurrently with us. Make sure that anything after
+ // this point does not assume that we are the only GC thread
+ // running. Note: of course, the actual marking work will
+ // not start until the safepoint itself is released in
+ // SuspendibleThreadSet::desynchronize().
+ doConcurrentMark();
+ }
+
+ return true;
+}
+
+void G1CollectedHeap::init_for_evac_failure(OopsInHeapRegionClosure* cl) {
+ _drain_in_progress = false;
+ set_evac_failure_closure(cl);
+ _evac_failure_scan_stack = new (ResourceObj::C_HEAP, mtGC) GrowableArray<oop>(40, true);
+}
+
+void G1CollectedHeap::finalize_for_evac_failure() {
+ assert(_evac_failure_scan_stack != NULL &&
+ _evac_failure_scan_stack->length() == 0,
+ "Postcondition");
+ assert(!_drain_in_progress, "Postcondition");
+ delete _evac_failure_scan_stack;
+ _evac_failure_scan_stack = NULL;
+}
+
+void G1CollectedHeap::remove_self_forwarding_pointers() {
+ double remove_self_forwards_start = os::elapsedTime();
+
+ set_par_threads();
+ G1ParRemoveSelfForwardPtrsTask rsfp_task(this);
+ workers()->run_task(&rsfp_task);
+ set_par_threads(0);
+
+ // Now restore saved marks, if any.
+ assert(_objs_with_preserved_marks.size() ==
+ _preserved_marks_of_objs.size(), "Both or none.");
+ while (!_objs_with_preserved_marks.is_empty()) {
+ oop obj = _objs_with_preserved_marks.pop();
+ markOop m = _preserved_marks_of_objs.pop();
+ obj->set_mark(m);
+ }
+ _objs_with_preserved_marks.clear(true);
+ _preserved_marks_of_objs.clear(true);
+
+ g1_policy()->phase_times()->record_evac_fail_remove_self_forwards((os::elapsedTime() - remove_self_forwards_start) * 1000.0);
+}
+
+void G1CollectedHeap::push_on_evac_failure_scan_stack(oop obj) {
+ _evac_failure_scan_stack->push(obj);
+}
+
+void G1CollectedHeap::drain_evac_failure_scan_stack() {
+ assert(_evac_failure_scan_stack != NULL, "precondition");
+
+ while (_evac_failure_scan_stack->length() > 0) {
+ oop obj = _evac_failure_scan_stack->pop();
+ _evac_failure_closure->set_region(heap_region_containing(obj));
+ obj->oop_iterate_backwards(_evac_failure_closure);
+ }
+}
+
+oop
+G1CollectedHeap::handle_evacuation_failure_par(G1ParScanThreadState* _par_scan_state,
+ oop old) {
+ assert(obj_in_cs(old),
+ err_msg("obj: "PTR_FORMAT" should still be in the CSet",
+ p2i(old)));
+ markOop m = old->mark();
+ oop forward_ptr = old->forward_to_atomic(old);
+ if (forward_ptr == NULL) {
+ // Forward-to-self succeeded.
+ assert(_par_scan_state != NULL, "par scan state");
+ OopsInHeapRegionClosure* cl = _par_scan_state->evac_failure_closure();
+ uint queue_num = _par_scan_state->queue_num();
+
+ _evacuation_failed = true;
+ _evacuation_failed_info_array[queue_num].register_copy_failure(old->size());
+ if (_evac_failure_closure != cl) {
+ MutexLockerEx x(EvacFailureStack_lock, Mutex::_no_safepoint_check_flag);
+ assert(!_drain_in_progress,
+ "Should only be true while someone holds the lock.");
+ // Set the global evac-failure closure to the current thread's.
+ assert(_evac_failure_closure == NULL, "Or locking has failed.");
+ set_evac_failure_closure(cl);
+ // Now do the common part.
+ handle_evacuation_failure_common(old, m);
+ // Reset to NULL.
+ set_evac_failure_closure(NULL);
+ } else {
+ // The lock is already held, and this is recursive.
+ assert(_drain_in_progress, "This should only be the recursive case.");
+ handle_evacuation_failure_common(old, m);
+ }
+ return old;
+ } else {
+ // Forward-to-self failed. Either someone else managed to allocate
+ // space for this object (old != forward_ptr) or they beat us in
+ // self-forwarding it (old == forward_ptr).
+ assert(old == forward_ptr || !obj_in_cs(forward_ptr),
+ err_msg("obj: "PTR_FORMAT" forwarded to: "PTR_FORMAT" "
+ "should not be in the CSet",
+ p2i(old), p2i(forward_ptr)));
+ return forward_ptr;
+ }
+}
+
+void G1CollectedHeap::handle_evacuation_failure_common(oop old, markOop m) {
+ preserve_mark_if_necessary(old, m);
+
+ HeapRegion* r = heap_region_containing(old);
+ if (!r->evacuation_failed()) {
+ r->set_evacuation_failed(true);
+ _hr_printer.evac_failure(r);
+ }
+
+ push_on_evac_failure_scan_stack(old);
+
+ if (!_drain_in_progress) {
+ // prevent recursion in copy_to_survivor_space()
+ _drain_in_progress = true;
+ drain_evac_failure_scan_stack();
+ _drain_in_progress = false;
+ }
+}
+
+void G1CollectedHeap::preserve_mark_if_necessary(oop obj, markOop m) {
+ assert(evacuation_failed(), "Oversaving!");
+ // We want to call the "for_promotion_failure" version only in the
+ // case of a promotion failure.
+ if (m->must_be_preserved_for_promotion_failure(obj)) {
+ _objs_with_preserved_marks.push(obj);
+ _preserved_marks_of_objs.push(m);
+ }
+}
+
+void G1ParCopyHelper::mark_object(oop obj) {
+ assert(!_g1->heap_region_containing(obj)->in_collection_set(), "should not mark objects in the CSet");
+
+ // We know that the object is not moving so it's safe to read its size.
+ _cm->grayRoot(obj, (size_t) obj->size(), _worker_id);
+}
+
+void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
+ assert(from_obj->is_forwarded(), "from obj should be forwarded");
+ assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
+ assert(from_obj != to_obj, "should not be self-forwarded");
+
+ assert(_g1->heap_region_containing(from_obj)->in_collection_set(), "from obj should be in the CSet");
+ assert(!_g1->heap_region_containing(to_obj)->in_collection_set(), "should not mark objects in the CSet");
+
+ // The object might be in the process of being copied by another
+ // worker so we cannot trust that its to-space image is
+ // well-formed. So we have to read its size from its from-space
+ // image which we know should not be changing.
+ _cm->grayRoot(to_obj, (size_t) from_obj->size(), _worker_id);
+}
+
+template <class T>
+void G1ParCopyHelper::do_klass_barrier(T* p, oop new_obj) {
+ if (_g1->heap_region_containing_raw(new_obj)->is_young()) {
+ _scanned_klass->record_modified_oops();
+ }
+}
+
+template <G1Barrier barrier, G1Mark do_mark_object>
+template <class T>
+void G1ParCopyClosure<barrier, do_mark_object>::do_oop_work(T* 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");
+
+ const InCSetState state = _g1->in_cset_state(obj);
+ if (state.is_in_cset()) {
+ oop forwardee;
+ markOop m = obj->mark();
+ if (m->is_marked()) {
+ forwardee = (oop) m->decode_pointer();
+ } else {
+ forwardee = _par_scan_state->copy_to_survivor_space(state, obj, m);
+ }
+ assert(forwardee != NULL, "forwardee should not be NULL");
+ oopDesc::encode_store_heap_oop(p, forwardee);
+ if (do_mark_object != G1MarkNone && forwardee != obj) {
+ // If the object is self-forwarded we don't need to explicitly
+ // mark it, the evacuation failure protocol will do so.
+ mark_forwarded_object(obj, forwardee);
+ }
+
+ if (barrier == G1BarrierKlass) {
+ do_klass_barrier(p, forwardee);
+ }
+ } else {
+ if (state.is_humongous()) {
+ _g1->set_humongous_is_live(obj);
+ }
+ // The object is not in collection set. If we're a root scanning
+ // closure during an initial mark pause then attempt to mark the object.
+ if (do_mark_object == G1MarkFromRoot) {
+ mark_object(obj);
+ }
+ }
+
+ if (barrier == G1BarrierEvac) {
+ _par_scan_state->update_rs(_from, p, _worker_id);
+ }
+}
+
+template void G1ParCopyClosure<G1BarrierEvac, G1MarkNone>::do_oop_work(oop* p);
+template void G1ParCopyClosure<G1BarrierEvac, G1MarkNone>::do_oop_work(narrowOop* p);
+
+class G1ParEvacuateFollowersClosure : public VoidClosure {
+protected:
+ G1CollectedHeap* _g1h;
+ G1ParScanThreadState* _par_scan_state;
+ RefToScanQueueSet* _queues;
+ ParallelTaskTerminator* _terminator;
+
+ G1ParScanThreadState* par_scan_state() { return _par_scan_state; }
+ RefToScanQueueSet* queues() { return _queues; }
+ ParallelTaskTerminator* terminator() { return _terminator; }
+
+public:
+ G1ParEvacuateFollowersClosure(G1CollectedHeap* g1h,
+ G1ParScanThreadState* par_scan_state,
+ RefToScanQueueSet* queues,
+ ParallelTaskTerminator* terminator)
+ : _g1h(g1h), _par_scan_state(par_scan_state),
+ _queues(queues), _terminator(terminator) {}
+
+ void do_void();
+
+private:
+ inline bool offer_termination();
+};
+
+bool G1ParEvacuateFollowersClosure::offer_termination() {
+ G1ParScanThreadState* const pss = par_scan_state();
+ pss->start_term_time();
+ const bool res = terminator()->offer_termination();
+ pss->end_term_time();
+ return res;
+}
+
+void G1ParEvacuateFollowersClosure::do_void() {
+ G1ParScanThreadState* const pss = par_scan_state();
+ pss->trim_queue();
+ do {
+ pss->steal_and_trim_queue(queues());
+ } while (!offer_termination());
+}
+
+class G1KlassScanClosure : public KlassClosure {
+ G1ParCopyHelper* _closure;
+ bool _process_only_dirty;
+ int _count;
+ public:
+ G1KlassScanClosure(G1ParCopyHelper* closure, bool process_only_dirty)
+ : _process_only_dirty(process_only_dirty), _closure(closure), _count(0) {}
+ void do_klass(Klass* klass) {
+ // If the klass has not been dirtied we know that there's
+ // no references into the young gen and we can skip it.
+ if (!_process_only_dirty || klass->has_modified_oops()) {
+ // Clean the klass since we're going to scavenge all the metadata.
+ klass->clear_modified_oops();
+
+ // Tell the closure that this klass is the Klass to scavenge
+ // and is the one to dirty if oops are left pointing into the young gen.
+ _closure->set_scanned_klass(klass);
+
+ klass->oops_do(_closure);
+
+ _closure->set_scanned_klass(NULL);
+ }
+ _count++;
+ }
+};
+
+class G1ParTask : public AbstractGangTask {
+protected:
+ G1CollectedHeap* _g1h;
+ RefToScanQueueSet *_queues;
+ G1RootProcessor* _root_processor;
+ ParallelTaskTerminator _terminator;
+ uint _n_workers;
+
+ Mutex _stats_lock;
+ Mutex* stats_lock() { return &_stats_lock; }
+
+public:
+ G1ParTask(G1CollectedHeap* g1h, RefToScanQueueSet *task_queues, G1RootProcessor* root_processor)
+ : AbstractGangTask("G1 collection"),
+ _g1h(g1h),
+ _queues(task_queues),
+ _root_processor(root_processor),
+ _terminator(0, _queues),
+ _stats_lock(Mutex::leaf, "parallel G1 stats lock", true)
+ {}
+
+ RefToScanQueueSet* queues() { return _queues; }
+
+ RefToScanQueue *work_queue(int i) {
+ return queues()->queue(i);
+ }
+
+ ParallelTaskTerminator* terminator() { return &_terminator; }
+
+ virtual void set_for_termination(uint active_workers) {
+ _root_processor->set_num_workers(active_workers);
+ terminator()->reset_for_reuse(active_workers);
+ _n_workers = active_workers;
+ }
+
+ // Helps out with CLD processing.
+ //
+ // During InitialMark we need to:
+ // 1) Scavenge all CLDs for the young GC.
+ // 2) Mark all objects directly reachable from strong CLDs.
+ template <G1Mark do_mark_object>
+ class G1CLDClosure : public CLDClosure {
+ G1ParCopyClosure<G1BarrierNone, do_mark_object>* _oop_closure;
+ G1ParCopyClosure<G1BarrierKlass, do_mark_object> _oop_in_klass_closure;
+ G1KlassScanClosure _klass_in_cld_closure;
+ bool _claim;
+
+ public:
+ G1CLDClosure(G1ParCopyClosure<G1BarrierNone, do_mark_object>* oop_closure,
+ bool only_young, bool claim)
+ : _oop_closure(oop_closure),
+ _oop_in_klass_closure(oop_closure->g1(),
+ oop_closure->pss(),
+ oop_closure->rp()),
+ _klass_in_cld_closure(&_oop_in_klass_closure, only_young),
+ _claim(claim) {
+
+ }
+
+ void do_cld(ClassLoaderData* cld) {
+ cld->oops_do(_oop_closure, &_klass_in_cld_closure, _claim);
+ }
+ };
+
+ void work(uint worker_id) {
+ if (worker_id >= _n_workers) return; // no work needed this round
+
+ _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::GCWorkerStart, worker_id, os::elapsedTime());
+
+ {
+ ResourceMark rm;
+ HandleMark hm;
+
+ ReferenceProcessor* rp = _g1h->ref_processor_stw();
+
+ G1ParScanThreadState pss(_g1h, worker_id, rp);
+ G1ParScanHeapEvacFailureClosure evac_failure_cl(_g1h, &pss, rp);
+
+ pss.set_evac_failure_closure(&evac_failure_cl);
+
+ bool only_young = _g1h->g1_policy()->gcs_are_young();
+
+ // Non-IM young GC.
+ G1ParCopyClosure<G1BarrierNone, G1MarkNone> scan_only_root_cl(_g1h, &pss, rp);
+ G1CLDClosure<G1MarkNone> scan_only_cld_cl(&scan_only_root_cl,
+ only_young, // Only process dirty klasses.
+ false); // No need to claim CLDs.
+ // IM young GC.
+ // Strong roots closures.
+ G1ParCopyClosure<G1BarrierNone, G1MarkFromRoot> scan_mark_root_cl(_g1h, &pss, rp);
+ G1CLDClosure<G1MarkFromRoot> scan_mark_cld_cl(&scan_mark_root_cl,
+ false, // Process all klasses.
+ true); // Need to claim CLDs.
+ // Weak roots closures.
+ G1ParCopyClosure<G1BarrierNone, G1MarkPromotedFromRoot> scan_mark_weak_root_cl(_g1h, &pss, rp);
+ G1CLDClosure<G1MarkPromotedFromRoot> scan_mark_weak_cld_cl(&scan_mark_weak_root_cl,
+ false, // Process all klasses.
+ true); // Need to claim CLDs.
+
+ OopClosure* strong_root_cl;
+ OopClosure* weak_root_cl;
+ CLDClosure* strong_cld_cl;
+ CLDClosure* weak_cld_cl;
+
+ bool trace_metadata = false;
+
+ if (_g1h->g1_policy()->during_initial_mark_pause()) {
+ // We also need to mark copied objects.
+ strong_root_cl = &scan_mark_root_cl;
+ strong_cld_cl = &scan_mark_cld_cl;
+ if (ClassUnloadingWithConcurrentMark) {
+ weak_root_cl = &scan_mark_weak_root_cl;
+ weak_cld_cl = &scan_mark_weak_cld_cl;
+ trace_metadata = true;
+ } else {
+ weak_root_cl = &scan_mark_root_cl;
+ weak_cld_cl = &scan_mark_cld_cl;
+ }
+ } else {
+ strong_root_cl = &scan_only_root_cl;
+ weak_root_cl = &scan_only_root_cl;
+ strong_cld_cl = &scan_only_cld_cl;
+ weak_cld_cl = &scan_only_cld_cl;
+ }
+
+ pss.start_strong_roots();
+
+ _root_processor->evacuate_roots(strong_root_cl,
+ weak_root_cl,
+ strong_cld_cl,
+ weak_cld_cl,
+ trace_metadata,
+ worker_id);
+
+ G1ParPushHeapRSClosure push_heap_rs_cl(_g1h, &pss);
+ _root_processor->scan_remembered_sets(&push_heap_rs_cl,
+ weak_root_cl,
+ worker_id);
+ pss.end_strong_roots();
+
+ {
+ double start = os::elapsedTime();
+ G1ParEvacuateFollowersClosure evac(_g1h, &pss, _queues, &_terminator);
+ evac.do_void();
+ double elapsed_sec = os::elapsedTime() - start;
+ double term_sec = pss.term_time();
+ _g1h->g1_policy()->phase_times()->add_time_secs(G1GCPhaseTimes::ObjCopy, worker_id, elapsed_sec - term_sec);
+ _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::Termination, worker_id, term_sec);
+ _g1h->g1_policy()->phase_times()->record_thread_work_item(G1GCPhaseTimes::Termination, worker_id, pss.term_attempts());
+ }
+ _g1h->g1_policy()->record_thread_age_table(pss.age_table());
+ _g1h->update_surviving_young_words(pss.surviving_young_words()+1);
+
+ if (PrintTerminationStats) {
+ MutexLocker x(stats_lock());
+ pss.print_termination_stats(worker_id);
+ }
+
+ assert(pss.queue_is_empty(), "should be empty");
+
+ // Close the inner scope so that the ResourceMark and HandleMark
+ // destructors are executed here and are included as part of the
+ // "GC Worker Time".
+ }
+ _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::GCWorkerEnd, worker_id, os::elapsedTime());
+ }
+};
+
+class G1StringSymbolTableUnlinkTask : public AbstractGangTask {
+private:
+ BoolObjectClosure* _is_alive;
+ int _initial_string_table_size;
+ int _initial_symbol_table_size;
+
+ bool _process_strings;
+ int _strings_processed;
+ int _strings_removed;
+
+ bool _process_symbols;
+ int _symbols_processed;
+ int _symbols_removed;
+
+public:
+ G1StringSymbolTableUnlinkTask(BoolObjectClosure* is_alive, bool process_strings, bool process_symbols) :
+ AbstractGangTask("String/Symbol Unlinking"),
+ _is_alive(is_alive),
+ _process_strings(process_strings), _strings_processed(0), _strings_removed(0),
+ _process_symbols(process_symbols), _symbols_processed(0), _symbols_removed(0) {
+
+ _initial_string_table_size = StringTable::the_table()->table_size();
+ _initial_symbol_table_size = SymbolTable::the_table()->table_size();
+ if (process_strings) {
+ StringTable::clear_parallel_claimed_index();
+ }
+ if (process_symbols) {
+ SymbolTable::clear_parallel_claimed_index();
+ }
+ }
+
+ ~G1StringSymbolTableUnlinkTask() {
+ guarantee(!_process_strings || StringTable::parallel_claimed_index() >= _initial_string_table_size,
+ err_msg("claim value %d after unlink less than initial string table size %d",
+ StringTable::parallel_claimed_index(), _initial_string_table_size));
+ guarantee(!_process_symbols || SymbolTable::parallel_claimed_index() >= _initial_symbol_table_size,
+ err_msg("claim value %d after unlink less than initial symbol table size %d",
+ SymbolTable::parallel_claimed_index(), _initial_symbol_table_size));
+
+ if (G1TraceStringSymbolTableScrubbing) {
+ gclog_or_tty->print_cr("Cleaned string and symbol table, "
+ "strings: "SIZE_FORMAT" processed, "SIZE_FORMAT" removed, "
+ "symbols: "SIZE_FORMAT" processed, "SIZE_FORMAT" removed",
+ strings_processed(), strings_removed(),
+ symbols_processed(), symbols_removed());
+ }
+ }
+
+ void work(uint worker_id) {
+ int strings_processed = 0;
+ int strings_removed = 0;
+ int symbols_processed = 0;
+ int symbols_removed = 0;
+ if (_process_strings) {
+ StringTable::possibly_parallel_unlink(_is_alive, &strings_processed, &strings_removed);
+ Atomic::add(strings_processed, &_strings_processed);
+ Atomic::add(strings_removed, &_strings_removed);
+ }
+ if (_process_symbols) {
+ SymbolTable::possibly_parallel_unlink(&symbols_processed, &symbols_removed);
+ Atomic::add(symbols_processed, &_symbols_processed);
+ Atomic::add(symbols_removed, &_symbols_removed);
+ }
+ }
+
+ size_t strings_processed() const { return (size_t)_strings_processed; }
+ size_t strings_removed() const { return (size_t)_strings_removed; }
+
+ size_t symbols_processed() const { return (size_t)_symbols_processed; }
+ size_t symbols_removed() const { return (size_t)_symbols_removed; }
+};
+
+class G1CodeCacheUnloadingTask VALUE_OBJ_CLASS_SPEC {
+private:
+ static Monitor* _lock;
+
+ BoolObjectClosure* const _is_alive;
+ const bool _unloading_occurred;
+ const uint _num_workers;
+
+ // Variables used to claim nmethods.
+ nmethod* _first_nmethod;
+ volatile nmethod* _claimed_nmethod;
+
+ // The list of nmethods that need to be processed by the second pass.
+ volatile nmethod* _postponed_list;
+ volatile uint _num_entered_barrier;
+
+ public:
+ G1CodeCacheUnloadingTask(uint num_workers, BoolObjectClosure* is_alive, bool unloading_occurred) :
+ _is_alive(is_alive),
+ _unloading_occurred(unloading_occurred),
+ _num_workers(num_workers),
+ _first_nmethod(NULL),
+ _claimed_nmethod(NULL),
+ _postponed_list(NULL),
+ _num_entered_barrier(0)
+ {
+ nmethod::increase_unloading_clock();
+ // Get first alive nmethod
+ NMethodIterator iter = NMethodIterator();
+ if(iter.next_alive()) {
+ _first_nmethod = iter.method();
+ }
+ _claimed_nmethod = (volatile nmethod*)_first_nmethod;
+ }
+
+ ~G1CodeCacheUnloadingTask() {
+ CodeCache::verify_clean_inline_caches();
+
+ CodeCache::set_needs_cache_clean(false);
+ guarantee(CodeCache::scavenge_root_nmethods() == NULL, "Must be");
+
+ CodeCache::verify_icholder_relocations();
+ }
+
+ private:
+ void add_to_postponed_list(nmethod* nm) {
+ nmethod* old;
+ do {
+ old = (nmethod*)_postponed_list;
+ nm->set_unloading_next(old);
+ } while ((nmethod*)Atomic::cmpxchg_ptr(nm, &_postponed_list, old) != old);
+ }
+
+ void clean_nmethod(nmethod* nm) {
+ bool postponed = nm->do_unloading_parallel(_is_alive, _unloading_occurred);
+
+ if (postponed) {
+ // This nmethod referred to an nmethod that has not been cleaned/unloaded yet.
+ add_to_postponed_list(nm);
+ }
+
+ // Mark that this thread has been cleaned/unloaded.
+ // After this call, it will be safe to ask if this nmethod was unloaded or not.
+ nm->set_unloading_clock(nmethod::global_unloading_clock());
+ }
+
+ void clean_nmethod_postponed(nmethod* nm) {
+ nm->do_unloading_parallel_postponed(_is_alive, _unloading_occurred);
+ }
+
+ static const int MaxClaimNmethods = 16;
+
+ void claim_nmethods(nmethod** claimed_nmethods, int *num_claimed_nmethods) {
+ nmethod* first;
+ NMethodIterator last;
+
+ do {
+ *num_claimed_nmethods = 0;
+
+ first = (nmethod*)_claimed_nmethod;
+ last = NMethodIterator(first);
+
+ if (first != NULL) {
+
+ for (int i = 0; i < MaxClaimNmethods; i++) {
+ if (!last.next_alive()) {
+ break;
+ }
+ claimed_nmethods[i] = last.method();
+ (*num_claimed_nmethods)++;
+ }
+ }
+
+ } while ((nmethod*)Atomic::cmpxchg_ptr(last.method(), &_claimed_nmethod, first) != first);
+ }
+
+ nmethod* claim_postponed_nmethod() {
+ nmethod* claim;
+ nmethod* next;
+
+ do {
+ claim = (nmethod*)_postponed_list;
+ if (claim == NULL) {
+ return NULL;
+ }
+
+ next = claim->unloading_next();
+
+ } while ((nmethod*)Atomic::cmpxchg_ptr(next, &_postponed_list, claim) != claim);
+
+ return claim;
+ }
+
+ public:
+ // Mark that we're done with the first pass of nmethod cleaning.
+ void barrier_mark(uint worker_id) {
+ MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
+ _num_entered_barrier++;
+ if (_num_entered_barrier == _num_workers) {
+ ml.notify_all();
+ }
+ }
+
+ // See if we have to wait for the other workers to
+ // finish their first-pass nmethod cleaning work.
+ void barrier_wait(uint worker_id) {
+ if (_num_entered_barrier < _num_workers) {
+ MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
+ while (_num_entered_barrier < _num_workers) {
+ ml.wait(Mutex::_no_safepoint_check_flag, 0, false);
+ }
+ }
+ }
+
+ // Cleaning and unloading of nmethods. Some work has to be postponed
+ // to the second pass, when we know which nmethods survive.
+ void work_first_pass(uint worker_id) {
+ // The first nmethods is claimed by the first worker.
+ if (worker_id == 0 && _first_nmethod != NULL) {
+ clean_nmethod(_first_nmethod);
+ _first_nmethod = NULL;
+ }
+
+ int num_claimed_nmethods;
+ nmethod* claimed_nmethods[MaxClaimNmethods];
+
+ while (true) {
+ claim_nmethods(claimed_nmethods, &num_claimed_nmethods);
+
+ if (num_claimed_nmethods == 0) {
+ break;
+ }
+
+ for (int i = 0; i < num_claimed_nmethods; i++) {
+ clean_nmethod(claimed_nmethods[i]);
+ }
+ }
+ }
+
+ void work_second_pass(uint worker_id) {
+ nmethod* nm;
+ // Take care of postponed nmethods.
+ while ((nm = claim_postponed_nmethod()) != NULL) {
+ clean_nmethod_postponed(nm);
+ }
+ }
+};
+
+Monitor* G1CodeCacheUnloadingTask::_lock = new Monitor(Mutex::leaf, "Code Cache Unload lock", false, Monitor::_safepoint_check_never);
+
+class G1KlassCleaningTask : public StackObj {
+ BoolObjectClosure* _is_alive;
+ volatile jint _clean_klass_tree_claimed;
+ ClassLoaderDataGraphKlassIteratorAtomic _klass_iterator;
+
+ public:
+ G1KlassCleaningTask(BoolObjectClosure* is_alive) :
+ _is_alive(is_alive),
+ _clean_klass_tree_claimed(0),
+ _klass_iterator() {
+ }
+
+ private:
+ bool claim_clean_klass_tree_task() {
+ if (_clean_klass_tree_claimed) {
+ return false;
+ }
+
+ return Atomic::cmpxchg(1, (jint*)&_clean_klass_tree_claimed, 0) == 0;
+ }
+
+ InstanceKlass* claim_next_klass() {
+ Klass* klass;
+ do {
+ klass =_klass_iterator.next_klass();
+ } while (klass != NULL && !klass->oop_is_instance());
+
+ return (InstanceKlass*)klass;
+ }
+
+public:
+
+ void clean_klass(InstanceKlass* ik) {
+ ik->clean_implementors_list(_is_alive);
+ ik->clean_method_data(_is_alive);
+
+ // G1 specific cleanup work that has
+ // been moved here to be done in parallel.
+ ik->clean_dependent_nmethods();
+ }
+
+ void work() {
+ ResourceMark rm;
+
+ // One worker will clean the subklass/sibling klass tree.
+ if (claim_clean_klass_tree_task()) {
+ Klass::clean_subklass_tree(_is_alive);
+ }
+
+ // All workers will help cleaning the classes,
+ InstanceKlass* klass;
+ while ((klass = claim_next_klass()) != NULL) {
+ clean_klass(klass);
+ }
+ }
+};
+
+// To minimize the remark pause times, the tasks below are done in parallel.
+class G1ParallelCleaningTask : public AbstractGangTask {
+private:
+ G1StringSymbolTableUnlinkTask _string_symbol_task;
+ G1CodeCacheUnloadingTask _code_cache_task;
+ G1KlassCleaningTask _klass_cleaning_task;
+
+public:
+ // The constructor is run in the VMThread.
+ G1ParallelCleaningTask(BoolObjectClosure* is_alive, bool process_strings, bool process_symbols, uint num_workers, bool unloading_occurred) :
+ AbstractGangTask("Parallel Cleaning"),
+ _string_symbol_task(is_alive, process_strings, process_symbols),
+ _code_cache_task(num_workers, is_alive, unloading_occurred),
+ _klass_cleaning_task(is_alive) {
+ }
+
+ // The parallel work done by all worker threads.
+ void work(uint worker_id) {
+ // Do first pass of code cache cleaning.
+ _code_cache_task.work_first_pass(worker_id);
+
+ // Let the threads mark that the first pass is done.
+ _code_cache_task.barrier_mark(worker_id);
+
+ // Clean the Strings and Symbols.
+ _string_symbol_task.work(worker_id);
+
+ // Wait for all workers to finish the first code cache cleaning pass.
+ _code_cache_task.barrier_wait(worker_id);
+
+ // Do the second code cache cleaning work, which realize on
+ // the liveness information gathered during the first pass.
+ _code_cache_task.work_second_pass(worker_id);
+
+ // Clean all klasses that were not unloaded.
+ _klass_cleaning_task.work();
+ }
+};
+
+
+void G1CollectedHeap::parallel_cleaning(BoolObjectClosure* is_alive,
+ bool process_strings,
+ bool process_symbols,
+ bool class_unloading_occurred) {
+ uint n_workers = workers()->active_workers();
+
+ G1ParallelCleaningTask g1_unlink_task(is_alive, process_strings, process_symbols,
+ n_workers, class_unloading_occurred);
+ set_par_threads(n_workers);
+ workers()->run_task(&g1_unlink_task);
+ set_par_threads(0);
+}
+
+void G1CollectedHeap::unlink_string_and_symbol_table(BoolObjectClosure* is_alive,
+ bool process_strings, bool process_symbols) {
+ {
+ uint n_workers = workers()->active_workers();
+ G1StringSymbolTableUnlinkTask g1_unlink_task(is_alive, process_strings, process_symbols);
+ set_par_threads(n_workers);
+ workers()->run_task(&g1_unlink_task);
+ set_par_threads(0);
+ }
+
+ if (G1StringDedup::is_enabled()) {
+ G1StringDedup::unlink(is_alive);
+ }
+}
+
+class G1RedirtyLoggedCardsTask : public AbstractGangTask {
+ private:
+ DirtyCardQueueSet* _queue;
+ public:
+ G1RedirtyLoggedCardsTask(DirtyCardQueueSet* queue) : AbstractGangTask("Redirty Cards"), _queue(queue) { }
+
+ virtual void work(uint worker_id) {
+ G1GCPhaseTimes* phase_times = G1CollectedHeap::heap()->g1_policy()->phase_times();
+ G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::RedirtyCards, worker_id);
+
+ RedirtyLoggedCardTableEntryClosure cl;
+ _queue->par_apply_closure_to_all_completed_buffers(&cl);
+
+ phase_times->record_thread_work_item(G1GCPhaseTimes::RedirtyCards, worker_id, cl.num_processed());
+ }
+};
+
+void G1CollectedHeap::redirty_logged_cards() {
+ double redirty_logged_cards_start = os::elapsedTime();
+
+ uint n_workers = workers()->active_workers();
+
+ G1RedirtyLoggedCardsTask redirty_task(&dirty_card_queue_set());
+ dirty_card_queue_set().reset_for_par_iteration();
+ set_par_threads(n_workers);
+ workers()->run_task(&redirty_task);
+ set_par_threads(0);
+
+ DirtyCardQueueSet& dcq = JavaThread::dirty_card_queue_set();
+ dcq.merge_bufferlists(&dirty_card_queue_set());
+ assert(dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
+
+ g1_policy()->phase_times()->record_redirty_logged_cards_time_ms((os::elapsedTime() - redirty_logged_cards_start) * 1000.0);
+}
+
+// Weak Reference Processing support
+
+// An always "is_alive" closure that is used to preserve referents.
+// If the object is non-null then it's alive. Used in the preservation
+// of referent objects that are pointed to by reference objects
+// discovered by the CM ref processor.
+class G1AlwaysAliveClosure: public BoolObjectClosure {
+ G1CollectedHeap* _g1;
+public:
+ G1AlwaysAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
+ bool do_object_b(oop p) {
+ if (p != NULL) {
+ return true;
+ }
+ return false;
+ }
+};
+
+bool G1STWIsAliveClosure::do_object_b(oop p) {
+ // An object is reachable if it is outside the collection set,
+ // or is inside and copied.
+ return !_g1->obj_in_cs(p) || p->is_forwarded();
+}
+
+// Non Copying Keep Alive closure
+class G1KeepAliveClosure: public OopClosure {
+ G1CollectedHeap* _g1;
+public:
+ G1KeepAliveClosure(G1CollectedHeap* g1) : _g1(g1) {}
+ void do_oop(narrowOop* p) { guarantee(false, "Not needed"); }
+ void do_oop(oop* p) {
+ oop obj = *p;
+ assert(obj != NULL, "the caller should have filtered out NULL values");
+
+ const InCSetState cset_state = _g1->in_cset_state(obj);
+ if (!cset_state.is_in_cset_or_humongous()) {
+ return;
+ }
+ if (cset_state.is_in_cset()) {
+ assert( obj->is_forwarded(), "invariant" );
+ *p = obj->forwardee();
+ } else {
+ assert(!obj->is_forwarded(), "invariant" );
+ assert(cset_state.is_humongous(),
+ err_msg("Only allowed InCSet state is IsHumongous, but is %d", cset_state.value()));
+ _g1->set_humongous_is_live(obj);
+ }
+ }
+};
+
+// Copying Keep Alive closure - can be called from both
+// serial and parallel code as long as different worker
+// threads utilize different G1ParScanThreadState instances
+// and different queues.
+
+class G1CopyingKeepAliveClosure: public OopClosure {
+ G1CollectedHeap* _g1h;
+ OopClosure* _copy_non_heap_obj_cl;
+ G1ParScanThreadState* _par_scan_state;
+
+public:
+ G1CopyingKeepAliveClosure(G1CollectedHeap* g1h,
+ OopClosure* non_heap_obj_cl,
+ G1ParScanThreadState* pss):
+ _g1h(g1h),
+ _copy_non_heap_obj_cl(non_heap_obj_cl),
+ _par_scan_state(pss)
+ {}
+
+ virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+ virtual void do_oop( oop* p) { do_oop_work(p); }
+
+ template <class T> void do_oop_work(T* p) {
+ oop obj = oopDesc::load_decode_heap_oop(p);
+
+ if (_g1h->is_in_cset_or_humongous(obj)) {
+ // If the referent object has been forwarded (either copied
+ // to a new location or to itself in the event of an
+ // evacuation failure) then we need to update the reference
+ // field and, if both reference and referent are in the G1
+ // heap, update the RSet for the referent.
+ //
+ // If the referent has not been forwarded then we have to keep
+ // it alive by policy. Therefore we have copy the referent.
+ //
+ // If the reference field is in the G1 heap then we can push
+ // on the PSS queue. When the queue is drained (after each
+ // phase of reference processing) the object and it's followers
+ // will be copied, the reference field set to point to the
+ // new location, and the RSet updated. Otherwise we need to
+ // use the the non-heap or metadata closures directly to copy
+ // the referent object and update the pointer, while avoiding
+ // updating the RSet.
+
+ if (_g1h->is_in_g1_reserved(p)) {
+ _par_scan_state->push_on_queue(p);
+ } else {
+ assert(!Metaspace::contains((const void*)p),
+ err_msg("Unexpectedly found a pointer from metadata: " PTR_FORMAT, p2i(p)));
+ _copy_non_heap_obj_cl->do_oop(p);
+ }
+ }
+ }
+};
+
+// Serial drain queue closure. Called as the 'complete_gc'
+// closure for each discovered list in some of the
+// reference processing phases.
+
+class G1STWDrainQueueClosure: public VoidClosure {
+protected:
+ G1CollectedHeap* _g1h;
+ G1ParScanThreadState* _par_scan_state;
+
+ G1ParScanThreadState* par_scan_state() { return _par_scan_state; }
+
+public:
+ G1STWDrainQueueClosure(G1CollectedHeap* g1h, G1ParScanThreadState* pss) :
+ _g1h(g1h),
+ _par_scan_state(pss)
+ { }
+
+ void do_void() {
+ G1ParScanThreadState* const pss = par_scan_state();
+ pss->trim_queue();
+ }
+};
+
+// Parallel Reference Processing closures
+
+// Implementation of AbstractRefProcTaskExecutor for parallel reference
+// processing during G1 evacuation pauses.
+
+class G1STWRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
+private:
+ G1CollectedHeap* _g1h;
+ RefToScanQueueSet* _queues;
+ FlexibleWorkGang* _workers;
+ uint _active_workers;
+
+public:
+ G1STWRefProcTaskExecutor(G1CollectedHeap* g1h,
+ FlexibleWorkGang* workers,
+ RefToScanQueueSet *task_queues,
+ uint n_workers) :
+ _g1h(g1h),
+ _queues(task_queues),
+ _workers(workers),
+ _active_workers(n_workers)
+ {
+ assert(n_workers > 0, "shouldn't call this otherwise");
+ }
+
+ // Executes the given task using concurrent marking worker threads.
+ virtual void execute(ProcessTask& task);
+ virtual void execute(EnqueueTask& task);
+};
+
+// Gang task for possibly parallel reference processing
+
+class G1STWRefProcTaskProxy: public AbstractGangTask {
+ typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
+ ProcessTask& _proc_task;
+ G1CollectedHeap* _g1h;
+ RefToScanQueueSet *_task_queues;
+ ParallelTaskTerminator* _terminator;
+
+public:
+ G1STWRefProcTaskProxy(ProcessTask& proc_task,
+ G1CollectedHeap* g1h,
+ RefToScanQueueSet *task_queues,
+ ParallelTaskTerminator* terminator) :
+ AbstractGangTask("Process reference objects in parallel"),
+ _proc_task(proc_task),
+ _g1h(g1h),
+ _task_queues(task_queues),
+ _terminator(terminator)
+ {}
+
+ virtual void work(uint worker_id) {
+ // The reference processing task executed by a single worker.
+ ResourceMark rm;
+ HandleMark hm;
+
+ G1STWIsAliveClosure is_alive(_g1h);
+
+ G1ParScanThreadState pss(_g1h, worker_id, NULL);
+ G1ParScanHeapEvacFailureClosure evac_failure_cl(_g1h, &pss, NULL);
+
+ pss.set_evac_failure_closure(&evac_failure_cl);
+
+ G1ParScanExtRootClosure only_copy_non_heap_cl(_g1h, &pss, NULL);
+
+ G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(_g1h, &pss, NULL);
+
+ OopClosure* copy_non_heap_cl = &only_copy_non_heap_cl;
+
+ if (_g1h->g1_policy()->during_initial_mark_pause()) {
+ // We also need to mark copied objects.
+ copy_non_heap_cl = ©_mark_non_heap_cl;
+ }
+
+ // Keep alive closure.
+ G1CopyingKeepAliveClosure keep_alive(_g1h, copy_non_heap_cl, &pss);
+
+ // Complete GC closure
+ G1ParEvacuateFollowersClosure drain_queue(_g1h, &pss, _task_queues, _terminator);
+
+ // Call the reference processing task's work routine.
+ _proc_task.work(worker_id, is_alive, keep_alive, drain_queue);
+
+ // Note we cannot assert that the refs array is empty here as not all
+ // of the processing tasks (specifically phase2 - pp2_work) execute
+ // the complete_gc closure (which ordinarily would drain the queue) so
+ // the queue may not be empty.
+ }
+};
+
+// Driver routine for parallel reference processing.
+// Creates an instance of the ref processing gang
+// task and has the worker threads execute it.
+void G1STWRefProcTaskExecutor::execute(ProcessTask& proc_task) {
+ assert(_workers != NULL, "Need parallel worker threads.");
+
+ ParallelTaskTerminator terminator(_active_workers, _queues);
+ G1STWRefProcTaskProxy proc_task_proxy(proc_task, _g1h, _queues, &terminator);
+
+ _g1h->set_par_threads(_active_workers);
+ _workers->run_task(&proc_task_proxy);
+ _g1h->set_par_threads(0);
+}
+
+// Gang task for parallel reference enqueueing.
+
+class G1STWRefEnqueueTaskProxy: public AbstractGangTask {
+ typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
+ EnqueueTask& _enq_task;
+
+public:
+ G1STWRefEnqueueTaskProxy(EnqueueTask& enq_task) :
+ AbstractGangTask("Enqueue reference objects in parallel"),
+ _enq_task(enq_task)
+ { }
+
+ virtual void work(uint worker_id) {
+ _enq_task.work(worker_id);
+ }
+};
+
+// Driver routine for parallel reference enqueueing.
+// Creates an instance of the ref enqueueing gang
+// task and has the worker threads execute it.
+
+void G1STWRefProcTaskExecutor::execute(EnqueueTask& enq_task) {
+ assert(_workers != NULL, "Need parallel worker threads.");
+
+ G1STWRefEnqueueTaskProxy enq_task_proxy(enq_task);
+
+ _g1h->set_par_threads(_active_workers);
+ _workers->run_task(&enq_task_proxy);
+ _g1h->set_par_threads(0);
+}
+
+// End of weak reference support closures
+
+// Abstract task used to preserve (i.e. copy) any referent objects
+// that are in the collection set and are pointed to by reference
+// objects discovered by the CM ref processor.
+
+class G1ParPreserveCMReferentsTask: public AbstractGangTask {
+protected:
+ G1CollectedHeap* _g1h;
+ RefToScanQueueSet *_queues;
+ ParallelTaskTerminator _terminator;
+ uint _n_workers;
+
+public:
+ G1ParPreserveCMReferentsTask(G1CollectedHeap* g1h, uint workers, RefToScanQueueSet *task_queues) :
+ AbstractGangTask("ParPreserveCMReferents"),
+ _g1h(g1h),
+ _queues(task_queues),
+ _terminator(workers, _queues),
+ _n_workers(workers)
+ { }
+
+ void work(uint worker_id) {
+ ResourceMark rm;
+ HandleMark hm;
+
+ G1ParScanThreadState pss(_g1h, worker_id, NULL);
+ G1ParScanHeapEvacFailureClosure evac_failure_cl(_g1h, &pss, NULL);
+
+ pss.set_evac_failure_closure(&evac_failure_cl);
+
+ assert(pss.queue_is_empty(), "both queue and overflow should be empty");
+
+ G1ParScanExtRootClosure only_copy_non_heap_cl(_g1h, &pss, NULL);
+
+ G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(_g1h, &pss, NULL);
+
+ OopClosure* copy_non_heap_cl = &only_copy_non_heap_cl;
+
+ if (_g1h->g1_policy()->during_initial_mark_pause()) {
+ // We also need to mark copied objects.
+ copy_non_heap_cl = ©_mark_non_heap_cl;
+ }
+
+ // Is alive closure
+ G1AlwaysAliveClosure always_alive(_g1h);
+
+ // Copying keep alive closure. Applied to referent objects that need
+ // to be copied.
+ G1CopyingKeepAliveClosure keep_alive(_g1h, copy_non_heap_cl, &pss);
+
+ ReferenceProcessor* rp = _g1h->ref_processor_cm();
+
+ uint limit = ReferenceProcessor::number_of_subclasses_of_ref() * rp->max_num_q();
+ uint stride = MIN2(MAX2(_n_workers, 1U), limit);
+
+ // limit is set using max_num_q() - which was set using ParallelGCThreads.
+ // So this must be true - but assert just in case someone decides to
+ // change the worker ids.
+ assert(worker_id < limit, "sanity");
+ assert(!rp->discovery_is_atomic(), "check this code");
+
+ // Select discovered lists [i, i+stride, i+2*stride,...,limit)
+ for (uint idx = worker_id; idx < limit; idx += stride) {
+ DiscoveredList& ref_list = rp->discovered_refs()[idx];
+
+ DiscoveredListIterator iter(ref_list, &keep_alive, &always_alive);
+ while (iter.has_next()) {
+ // Since discovery is not atomic for the CM ref processor, we
+ // can see some null referent objects.
+ iter.load_ptrs(DEBUG_ONLY(true));
+ oop ref = iter.obj();
+
+ // This will filter nulls.
+ if (iter.is_referent_alive()) {
+ iter.make_referent_alive();
+ }
+ iter.move_to_next();
+ }
+ }
+
+ // Drain the queue - which may cause stealing
+ G1ParEvacuateFollowersClosure drain_queue(_g1h, &pss, _queues, &_terminator);
+ drain_queue.do_void();
+ // Allocation buffers were retired at the end of G1ParEvacuateFollowersClosure
+ assert(pss.queue_is_empty(), "should be");
+ }
+};
+
+// Weak Reference processing during an evacuation pause (part 1).
+void G1CollectedHeap::process_discovered_references(uint no_of_gc_workers) {
+ double ref_proc_start = os::elapsedTime();
+
+ ReferenceProcessor* rp = _ref_processor_stw;
+ assert(rp->discovery_enabled(), "should have been enabled");
+
+ // Any reference objects, in the collection set, that were 'discovered'
+ // by the CM ref processor should have already been copied (either by
+ // applying the external root copy closure to the discovered lists, or
+ // by following an RSet entry).
+ //
+ // But some of the referents, that are in the collection set, that these
+ // reference objects point to may not have been copied: the STW ref
+ // processor would have seen that the reference object had already
+ // been 'discovered' and would have skipped discovering the reference,
+ // but would not have treated the reference object as a regular oop.
+ // As a result the copy closure would not have been applied to the
+ // referent object.
+ //
+ // We need to explicitly copy these referent objects - the references
+ // will be processed at the end of remarking.
+ //
+ // We also need to do this copying before we process the reference
+ // objects discovered by the STW ref processor in case one of these
+ // referents points to another object which is also referenced by an
+ // object discovered by the STW ref processor.
+
+ assert(no_of_gc_workers == workers()->active_workers(), "Need to reset active GC workers");
+
+ set_par_threads(no_of_gc_workers);
+ G1ParPreserveCMReferentsTask keep_cm_referents(this,
+ no_of_gc_workers,
+ _task_queues);
+
+ workers()->run_task(&keep_cm_referents);
+
+ set_par_threads(0);
+
+ // Closure to test whether a referent is alive.
+ G1STWIsAliveClosure is_alive(this);
+
+ // Even when parallel reference processing is enabled, the processing
+ // of JNI refs is serial and performed serially by the current thread
+ // rather than by a worker. The following PSS will be used for processing
+ // JNI refs.
+
+ // Use only a single queue for this PSS.
+ G1ParScanThreadState pss(this, 0, NULL);
+
+ // We do not embed a reference processor in the copying/scanning
+ // closures while we're actually processing the discovered
+ // reference objects.
+ G1ParScanHeapEvacFailureClosure evac_failure_cl(this, &pss, NULL);
+
+ pss.set_evac_failure_closure(&evac_failure_cl);
+
+ assert(pss.queue_is_empty(), "pre-condition");
+
+ G1ParScanExtRootClosure only_copy_non_heap_cl(this, &pss, NULL);
+
+ G1ParScanAndMarkExtRootClosure copy_mark_non_heap_cl(this, &pss, NULL);
+
+ OopClosure* copy_non_heap_cl = &only_copy_non_heap_cl;
+
+ if (g1_policy()->during_initial_mark_pause()) {
+ // We also need to mark copied objects.
+ copy_non_heap_cl = ©_mark_non_heap_cl;
+ }
+
+ // Keep alive closure.
+ G1CopyingKeepAliveClosure keep_alive(this, copy_non_heap_cl, &pss);
+
+ // Serial Complete GC closure
+ G1STWDrainQueueClosure drain_queue(this, &pss);
+
+ // Setup the soft refs policy...
+ rp->setup_policy(false);
+
+ ReferenceProcessorStats stats;
+ if (!rp->processing_is_mt()) {
+ // Serial reference processing...
+ stats = rp->process_discovered_references(&is_alive,
+ &keep_alive,
+ &drain_queue,
+ NULL,
+ _gc_timer_stw,
+ _gc_tracer_stw->gc_id());
+ } else {
+ // Parallel reference processing
+ assert(rp->num_q() == no_of_gc_workers, "sanity");
+ assert(no_of_gc_workers <= rp->max_num_q(), "sanity");
+
+ G1STWRefProcTaskExecutor par_task_executor(this, workers(), _task_queues, no_of_gc_workers);
+ stats = rp->process_discovered_references(&is_alive,
+ &keep_alive,
+ &drain_queue,
+ &par_task_executor,
+ _gc_timer_stw,
+ _gc_tracer_stw->gc_id());
+ }
+
+ _gc_tracer_stw->report_gc_reference_stats(stats);
+
+ // We have completed copying any necessary live referent objects.
+ assert(pss.queue_is_empty(), "both queue and overflow should be empty");
+
+ double ref_proc_time = os::elapsedTime() - ref_proc_start;
+ g1_policy()->phase_times()->record_ref_proc_time(ref_proc_time * 1000.0);
+}
+
+// Weak Reference processing during an evacuation pause (part 2).
+void G1CollectedHeap::enqueue_discovered_references(uint no_of_gc_workers) {
+ double ref_enq_start = os::elapsedTime();
+
+ ReferenceProcessor* rp = _ref_processor_stw;
+ assert(!rp->discovery_enabled(), "should have been disabled as part of processing");
+
+ // Now enqueue any remaining on the discovered lists on to
+ // the pending list.
+ if (!rp->processing_is_mt()) {
+ // Serial reference processing...
+ rp->enqueue_discovered_references();
+ } else {
+ // Parallel reference enqueueing
+
+ assert(no_of_gc_workers == workers()->active_workers(),
+ "Need to reset active workers");
+ assert(rp->num_q() == no_of_gc_workers, "sanity");
+ assert(no_of_gc_workers <= rp->max_num_q(), "sanity");
+
+ G1STWRefProcTaskExecutor par_task_executor(this, workers(), _task_queues, no_of_gc_workers);
+ rp->enqueue_discovered_references(&par_task_executor);
+ }
+
+ rp->verify_no_references_recorded();
+ assert(!rp->discovery_enabled(), "should have been disabled");
+
+ // FIXME
+ // CM's reference processing also cleans up the string and symbol tables.
+ // Should we do that here also? We could, but it is a serial operation
+ // and could significantly increase the pause time.
+
+ double ref_enq_time = os::elapsedTime() - ref_enq_start;
+ g1_policy()->phase_times()->record_ref_enq_time(ref_enq_time * 1000.0);
+}
+
+void G1CollectedHeap::evacuate_collection_set(EvacuationInfo& evacuation_info) {
+ _expand_heap_after_alloc_failure = true;
+ _evacuation_failed = false;
+
+ // Should G1EvacuationFailureALot be in effect for this GC?
+ NOT_PRODUCT(set_evacuation_failure_alot_for_current_gc();)
+
+ g1_rem_set()->prepare_for_oops_into_collection_set_do();
+
+ // Disable the hot card cache.
+ G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache();
+ hot_card_cache->reset_hot_cache_claimed_index();
+ hot_card_cache->set_use_cache(false);
+
+ const uint n_workers = workers()->active_workers();
+ assert(UseDynamicNumberOfGCThreads ||
+ n_workers == workers()->total_workers(),
+ "If not dynamic should be using all the workers");
+ set_par_threads(n_workers);
+
+
+ init_for_evac_failure(NULL);
+
+ assert(dirty_card_queue_set().completed_buffers_num() == 0, "Should be empty");
+ double start_par_time_sec = os::elapsedTime();
+ double end_par_time_sec;
+
+ {
+ G1RootProcessor root_processor(this);
+ G1ParTask g1_par_task(this, _task_queues, &root_processor);
+ // InitialMark needs claim bits to keep track of the marked-through CLDs.
+ if (g1_policy()->during_initial_mark_pause()) {
+ ClassLoaderDataGraph::clear_claimed_marks();
+ }
+
+ // The individual threads will set their evac-failure closures.
+ if (PrintTerminationStats) G1ParScanThreadState::print_termination_stats_hdr();
+ // These tasks use ShareHeap::_process_strong_tasks
+ assert(UseDynamicNumberOfGCThreads ||
+ workers()->active_workers() == workers()->total_workers(),
+ "If not dynamic should be using all the workers");
+ workers()->run_task(&g1_par_task);
+ end_par_time_sec = os::elapsedTime();
+
+ // Closing the inner scope will execute the destructor
+ // for the G1RootProcessor object. We record the current
+ // elapsed time before closing the scope so that time
+ // taken for the destructor is NOT included in the
+ // reported parallel time.
+ }
+
+ G1GCPhaseTimes* phase_times = g1_policy()->phase_times();
+
+ double par_time_ms = (end_par_time_sec - start_par_time_sec) * 1000.0;
+ phase_times->record_par_time(par_time_ms);
+
+ double code_root_fixup_time_ms =
+ (os::elapsedTime() - end_par_time_sec) * 1000.0;
+ phase_times->record_code_root_fixup_time(code_root_fixup_time_ms);
+
+ set_par_threads(0);
+
+ // Process any discovered reference objects - we have
+ // to do this _before_ we retire the GC alloc regions
+ // as we may have to copy some 'reachable' referent
+ // objects (and their reachable sub-graphs) that were
+ // not copied during the pause.
+ process_discovered_references(n_workers);
+
+ if (G1StringDedup::is_enabled()) {
+ double fixup_start = os::elapsedTime();
+
+ G1STWIsAliveClosure is_alive(this);
+ G1KeepAliveClosure keep_alive(this);
+ G1StringDedup::unlink_or_oops_do(&is_alive, &keep_alive, true, phase_times);
+
+ double fixup_time_ms = (os::elapsedTime() - fixup_start) * 1000.0;
+ phase_times->record_string_dedup_fixup_time(fixup_time_ms);
+ }
+
+ _allocator->release_gc_alloc_regions(n_workers, evacuation_info);
+ g1_rem_set()->cleanup_after_oops_into_collection_set_do();
+
+ // Reset and re-enable the hot card cache.
+ // Note the counts for the cards in the regions in the
+ // collection set are reset when the collection set is freed.
+ hot_card_cache->reset_hot_cache();
+ hot_card_cache->set_use_cache(true);
+
+ purge_code_root_memory();
+
+ finalize_for_evac_failure();
+
+ if (evacuation_failed()) {
+ remove_self_forwarding_pointers();
+
+ // Reset the G1EvacuationFailureALot counters and flags
+ // Note: the values are reset only when an actual
+ // evacuation failure occurs.
+ NOT_PRODUCT(reset_evacuation_should_fail();)
+ }
+
+ // Enqueue any remaining references remaining on the STW
+ // reference processor's discovered lists. We need to do
+ // this after the card table is cleaned (and verified) as
+ // the act of enqueueing entries on to the pending list
+ // will log these updates (and dirty their associated
+ // cards). We need these updates logged to update any
+ // RSets.
+ enqueue_discovered_references(n_workers);
+
+ redirty_logged_cards();
+ COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
+}
+
+void G1CollectedHeap::free_region(HeapRegion* hr,
+ FreeRegionList* free_list,
+ bool par,
+ bool locked) {
+ assert(!hr->is_free(), "the region should not be free");
+ assert(!hr->is_empty(), "the region should not be empty");
+ assert(_hrm.is_available(hr->hrm_index()), "region should be committed");
+ assert(free_list != NULL, "pre-condition");
+
+ if (G1VerifyBitmaps) {
+ MemRegion mr(hr->bottom(), hr->end());
+ concurrent_mark()->clearRangePrevBitmap(mr);
+ }
+
+ // Clear the card counts for this region.
+ // Note: we only need to do this if the region is not young
+ // (since we don't refine cards in young regions).
+ if (!hr->is_young()) {
+ _cg1r->hot_card_cache()->reset_card_counts(hr);
+ }
+ hr->hr_clear(par, true /* clear_space */, locked /* locked */);
+ free_list->add_ordered(hr);
+}
+
+void G1CollectedHeap::free_humongous_region(HeapRegion* hr,
+ FreeRegionList* free_list,
+ bool par) {
+ assert(hr->is_starts_humongous(), "this is only for starts humongous regions");
+ assert(free_list != NULL, "pre-condition");
+
+ size_t hr_capacity = hr->capacity();
+ // We need to read this before we make the region non-humongous,
+ // otherwise the information will be gone.
+ uint last_index = hr->last_hc_index();
+ hr->clear_humongous();
+ free_region(hr, free_list, par);
+
+ uint i = hr->hrm_index() + 1;
+ while (i < last_index) {
+ HeapRegion* curr_hr = region_at(i);
+ assert(curr_hr->is_continues_humongous(), "invariant");
+ curr_hr->clear_humongous();
+ free_region(curr_hr, free_list, par);
+ i += 1;
+ }
+}
+
+void G1CollectedHeap::remove_from_old_sets(const HeapRegionSetCount& old_regions_removed,
+ const HeapRegionSetCount& humongous_regions_removed) {
+ if (old_regions_removed.length() > 0 || humongous_regions_removed.length() > 0) {
+ MutexLockerEx x(OldSets_lock, Mutex::_no_safepoint_check_flag);
+ _old_set.bulk_remove(old_regions_removed);
+ _humongous_set.bulk_remove(humongous_regions_removed);
+ }
+
+}
+
+void G1CollectedHeap::prepend_to_freelist(FreeRegionList* list) {
+ assert(list != NULL, "list can't be null");
+ if (!list->is_empty()) {
+ MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
+ _hrm.insert_list_into_free_list(list);
+ }
+}
+
+void G1CollectedHeap::decrement_summary_bytes(size_t bytes) {
+ _allocator->decrease_used(bytes);
+}
+
+class G1ParCleanupCTTask : public AbstractGangTask {
+ G1SATBCardTableModRefBS* _ct_bs;
+ G1CollectedHeap* _g1h;
+ HeapRegion* volatile _su_head;
+public:
+ G1ParCleanupCTTask(G1SATBCardTableModRefBS* ct_bs,
+ G1CollectedHeap* g1h) :
+ AbstractGangTask("G1 Par Cleanup CT Task"),
+ _ct_bs(ct_bs), _g1h(g1h) { }
+
+ void work(uint worker_id) {
+ HeapRegion* r;
+ while (r = _g1h->pop_dirty_cards_region()) {
+ clear_cards(r);
+ }
+ }
+
+ void clear_cards(HeapRegion* r) {
+ // Cards of the survivors should have already been dirtied.
+ if (!r->is_survivor()) {
+ _ct_bs->clear(MemRegion(r->bottom(), r->end()));
+ }
+ }
+};
+
+#ifndef PRODUCT
+class G1VerifyCardTableCleanup: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
+ G1SATBCardTableModRefBS* _ct_bs;
+public:
+ G1VerifyCardTableCleanup(G1CollectedHeap* g1h, G1SATBCardTableModRefBS* ct_bs)
+ : _g1h(g1h), _ct_bs(ct_bs) { }
+ virtual bool doHeapRegion(HeapRegion* r) {
+ if (r->is_survivor()) {
+ _g1h->verify_dirty_region(r);
+ } else {
+ _g1h->verify_not_dirty_region(r);
+ }
+ return false;
+ }
+};
+
+void G1CollectedHeap::verify_not_dirty_region(HeapRegion* hr) {
+ // All of the region should be clean.
+ G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
+ MemRegion mr(hr->bottom(), hr->end());
+ ct_bs->verify_not_dirty_region(mr);
+}
+
+void G1CollectedHeap::verify_dirty_region(HeapRegion* hr) {
+ // We cannot guarantee that [bottom(),end()] is dirty. Threads
+ // dirty allocated blocks as they allocate them. The thread that
+ // retires each region and replaces it with a new one will do a
+ // maximal allocation to fill in [pre_dummy_top(),end()] but will
+ // not dirty that area (one less thing to have to do while holding
+ // a lock). So we can only verify that [bottom(),pre_dummy_top()]
+ // is dirty.
+ G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
+ MemRegion mr(hr->bottom(), hr->pre_dummy_top());
+ if (hr->is_young()) {
+ ct_bs->verify_g1_young_region(mr);
+ } else {
+ ct_bs->verify_dirty_region(mr);
+ }
+}
+
+void G1CollectedHeap::verify_dirty_young_list(HeapRegion* head) {
+ G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
+ for (HeapRegion* hr = head; hr != NULL; hr = hr->get_next_young_region()) {
+ verify_dirty_region(hr);
+ }
+}
+
+void G1CollectedHeap::verify_dirty_young_regions() {
+ verify_dirty_young_list(_young_list->first_region());
+}
+
+bool G1CollectedHeap::verify_no_bits_over_tams(const char* bitmap_name, CMBitMapRO* bitmap,
+ HeapWord* tams, HeapWord* end) {
+ guarantee(tams <= end,
+ err_msg("tams: "PTR_FORMAT" end: "PTR_FORMAT, p2i(tams), p2i(end)));
+ HeapWord* result = bitmap->getNextMarkedWordAddress(tams, end);
+ if (result < end) {
+ gclog_or_tty->cr();
+ gclog_or_tty->print_cr("## wrong marked address on %s bitmap: "PTR_FORMAT,
+ bitmap_name, p2i(result));
+ gclog_or_tty->print_cr("## %s tams: "PTR_FORMAT" end: "PTR_FORMAT,
+ bitmap_name, p2i(tams), p2i(end));
+ return false;
+ }
+ return true;
+}
+
+bool G1CollectedHeap::verify_bitmaps(const char* caller, HeapRegion* hr) {
+ CMBitMapRO* prev_bitmap = concurrent_mark()->prevMarkBitMap();
+ CMBitMapRO* next_bitmap = (CMBitMapRO*) concurrent_mark()->nextMarkBitMap();
+
+ HeapWord* bottom = hr->bottom();
+ HeapWord* ptams = hr->prev_top_at_mark_start();
+ HeapWord* ntams = hr->next_top_at_mark_start();
+ HeapWord* end = hr->end();
+
+ bool res_p = verify_no_bits_over_tams("prev", prev_bitmap, ptams, end);
+
+ bool res_n = true;
+ // We reset mark_in_progress() before we reset _cmThread->in_progress() and in this window
+ // we do the clearing of the next bitmap concurrently. Thus, we can not verify the bitmap
+ // if we happen to be in that state.
+ if (mark_in_progress() || !_cmThread->in_progress()) {
+ res_n = verify_no_bits_over_tams("next", next_bitmap, ntams, end);
+ }
+ if (!res_p || !res_n) {
+ gclog_or_tty->print_cr("#### Bitmap verification failed for "HR_FORMAT,
+ HR_FORMAT_PARAMS(hr));
+ gclog_or_tty->print_cr("#### Caller: %s", caller);
+ return false;
+ }
+ return true;
+}
+
+void G1CollectedHeap::check_bitmaps(const char* caller, HeapRegion* hr) {
+ if (!G1VerifyBitmaps) return;
+
+ guarantee(verify_bitmaps(caller, hr), "bitmap verification");
+}
+
+class G1VerifyBitmapClosure : public HeapRegionClosure {
+private:
+ const char* _caller;
+ G1CollectedHeap* _g1h;
+ bool _failures;
+
+public:
+ G1VerifyBitmapClosure(const char* caller, G1CollectedHeap* g1h) :
+ _caller(caller), _g1h(g1h), _failures(false) { }
+
+ bool failures() { return _failures; }
+
+ virtual bool doHeapRegion(HeapRegion* hr) {
+ if (hr->is_continues_humongous()) return false;
+
+ bool result = _g1h->verify_bitmaps(_caller, hr);
+ if (!result) {
+ _failures = true;
+ }
+ return false;
+ }
+};
+
+void G1CollectedHeap::check_bitmaps(const char* caller) {
+ if (!G1VerifyBitmaps) return;
+
+ G1VerifyBitmapClosure cl(caller, this);
+ heap_region_iterate(&cl);
+ guarantee(!cl.failures(), "bitmap verification");
+}
+
+class G1CheckCSetFastTableClosure : public HeapRegionClosure {
+ private:
+ bool _failures;
+ public:
+ G1CheckCSetFastTableClosure() : HeapRegionClosure(), _failures(false) { }
+
+ virtual bool doHeapRegion(HeapRegion* hr) {
+ uint i = hr->hrm_index();
+ InCSetState cset_state = (InCSetState) G1CollectedHeap::heap()->_in_cset_fast_test.get_by_index(i);
+ if (hr->is_humongous()) {
+ if (hr->in_collection_set()) {
+ gclog_or_tty->print_cr("\n## humongous region %u in CSet", i);
+ _failures = true;
+ return true;
+ }
+ if (cset_state.is_in_cset()) {
+ gclog_or_tty->print_cr("\n## inconsistent cset state %d for humongous region %u", cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ if (hr->is_continues_humongous() && cset_state.is_humongous()) {
+ gclog_or_tty->print_cr("\n## inconsistent cset state %d for continues humongous region %u", cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ } else {
+ if (cset_state.is_humongous()) {
+ gclog_or_tty->print_cr("\n## inconsistent cset state %d for non-humongous region %u", cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ if (hr->in_collection_set() != cset_state.is_in_cset()) {
+ gclog_or_tty->print_cr("\n## in CSet %d / cset state %d inconsistency for region %u",
+ hr->in_collection_set(), cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ if (cset_state.is_in_cset()) {
+ if (hr->is_young() != (cset_state.is_young())) {
+ gclog_or_tty->print_cr("\n## is_young %d / cset state %d inconsistency for region %u",
+ hr->is_young(), cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ if (hr->is_old() != (cset_state.is_old())) {
+ gclog_or_tty->print_cr("\n## is_old %d / cset state %d inconsistency for region %u",
+ hr->is_old(), cset_state.value(), i);
+ _failures = true;
+ return true;
+ }
+ }
+ }
+ return false;
+ }
+
+ bool failures() const { return _failures; }
+};
+
+bool G1CollectedHeap::check_cset_fast_test() {
+ G1CheckCSetFastTableClosure cl;
+ _hrm.iterate(&cl);
+ return !cl.failures();
+}
+#endif // PRODUCT
+
+void G1CollectedHeap::cleanUpCardTable() {
+ G1SATBCardTableModRefBS* ct_bs = g1_barrier_set();
+ double start = os::elapsedTime();
+
+ {
+ // Iterate over the dirty cards region list.
+ G1ParCleanupCTTask cleanup_task(ct_bs, this);
+
+ set_par_threads();
+ workers()->run_task(&cleanup_task);
+ set_par_threads(0);
+#ifndef PRODUCT
+ if (G1VerifyCTCleanup || VerifyAfterGC) {
+ G1VerifyCardTableCleanup cleanup_verifier(this, ct_bs);
+ heap_region_iterate(&cleanup_verifier);
+ }
+#endif
+ }
+
+ double elapsed = os::elapsedTime() - start;
+ g1_policy()->phase_times()->record_clear_ct_time(elapsed * 1000.0);
+}
+
+void G1CollectedHeap::free_collection_set(HeapRegion* cs_head, EvacuationInfo& evacuation_info) {
+ size_t pre_used = 0;
+ FreeRegionList local_free_list("Local List for CSet Freeing");
+
+ double young_time_ms = 0.0;
+ double non_young_time_ms = 0.0;
+
+ // Since the collection set is a superset of the the young list,
+ // all we need to do to clear the young list is clear its
+ // head and length, and unlink any young regions in the code below
+ _young_list->clear();
+
+ G1CollectorPolicy* policy = g1_policy();
+
+ double start_sec = os::elapsedTime();
+ bool non_young = true;
+
+ HeapRegion* cur = cs_head;
+ int age_bound = -1;
+ size_t rs_lengths = 0;
+
+ while (cur != NULL) {
+ assert(!is_on_master_free_list(cur), "sanity");
+ if (non_young) {
+ if (cur->is_young()) {
+ double end_sec = os::elapsedTime();
+ double elapsed_ms = (end_sec - start_sec) * 1000.0;
+ non_young_time_ms += elapsed_ms;
+
+ start_sec = os::elapsedTime();
+ non_young = false;
+ }
+ } else {
+ if (!cur->is_young()) {
+ double end_sec = os::elapsedTime();
+ double elapsed_ms = (end_sec - start_sec) * 1000.0;
+ young_time_ms += elapsed_ms;
+
+ start_sec = os::elapsedTime();
+ non_young = true;
+ }
+ }
+
+ rs_lengths += cur->rem_set()->occupied_locked();
+
+ HeapRegion* next = cur->next_in_collection_set();
+ assert(cur->in_collection_set(), "bad CS");
+ cur->set_next_in_collection_set(NULL);
+ clear_in_cset(cur);
+
+ if (cur->is_young()) {
+ int index = cur->young_index_in_cset();
+ assert(index != -1, "invariant");
+ assert((uint) index < policy->young_cset_region_length(), "invariant");
+ size_t words_survived = _surviving_young_words[index];
+ cur->record_surv_words_in_group(words_survived);
+
+ // At this point the we have 'popped' cur from the collection set
+ // (linked via next_in_collection_set()) but it is still in the
+ // young list (linked via next_young_region()). Clear the
+ // _next_young_region field.
+ cur->set_next_young_region(NULL);
+ } else {
+ int index = cur->young_index_in_cset();
+ assert(index == -1, "invariant");
+ }
+
+ assert( (cur->is_young() && cur->young_index_in_cset() > -1) ||
+ (!cur->is_young() && cur->young_index_in_cset() == -1),
+ "invariant" );
+
+ if (!cur->evacuation_failed()) {
+ MemRegion used_mr = cur->used_region();
+
+ // And the region is empty.
+ assert(!used_mr.is_empty(), "Should not have empty regions in a CS.");
+ pre_used += cur->used();
+ free_region(cur, &local_free_list, false /* par */, true /* locked */);
+ } else {
+ cur->uninstall_surv_rate_group();
+ if (cur->is_young()) {
+ cur->set_young_index_in_cset(-1);
+ }
+ cur->set_evacuation_failed(false);
+ // The region is now considered to be old.
+ cur->set_old();
+ _old_set.add(cur);
+ evacuation_info.increment_collectionset_used_after(cur->used());
+ }
+ cur = next;
+ }
+
+ evacuation_info.set_regions_freed(local_free_list.length());
+ policy->record_max_rs_lengths(rs_lengths);
+ policy->cset_regions_freed();
+
+ double end_sec = os::elapsedTime();
+ double elapsed_ms = (end_sec - start_sec) * 1000.0;
+
+ if (non_young) {
+ non_young_time_ms += elapsed_ms;
+ } else {
+ young_time_ms += elapsed_ms;
+ }
+
+ prepend_to_freelist(&local_free_list);
+ decrement_summary_bytes(pre_used);
+ policy->phase_times()->record_young_free_cset_time_ms(young_time_ms);
+ policy->phase_times()->record_non_young_free_cset_time_ms(non_young_time_ms);
+}
+
+class G1FreeHumongousRegionClosure : public HeapRegionClosure {
+ private:
+ FreeRegionList* _free_region_list;
+ HeapRegionSet* _proxy_set;
+ HeapRegionSetCount _humongous_regions_removed;
+ size_t _freed_bytes;
+ public:
+
+ G1FreeHumongousRegionClosure(FreeRegionList* free_region_list) :
+ _free_region_list(free_region_list), _humongous_regions_removed(), _freed_bytes(0) {
+ }
+
+ virtual bool doHeapRegion(HeapRegion* r) {
+ if (!r->is_starts_humongous()) {
+ return false;
+ }
+
+ G1CollectedHeap* g1h = G1CollectedHeap::heap();
+
+ oop obj = (oop)r->bottom();
+ CMBitMap* next_bitmap = g1h->concurrent_mark()->nextMarkBitMap();
+
+ // The following checks whether the humongous object is live are sufficient.
+ // The main additional check (in addition to having a reference from the roots
+ // or the young gen) is whether the humongous object has a remembered set entry.
+ //
+ // A humongous object cannot be live if there is no remembered set for it
+ // because:
+ // - there can be no references from within humongous starts regions referencing
+ // the object because we never allocate other objects into them.
+ // (I.e. there are no intra-region references that may be missed by the
+ // remembered set)
+ // - as soon there is a remembered set entry to the humongous starts region
+ // (i.e. it has "escaped" to an old object) this remembered set entry will stay
+ // until the end of a concurrent mark.
+ //
+ // It is not required to check whether the object has been found dead by marking
+ // or not, in fact it would prevent reclamation within a concurrent cycle, as
+ // all objects allocated during that time are considered live.
+ // SATB marking is even more conservative than the remembered set.
+ // So if at this point in the collection there is no remembered set entry,
+ // nobody has a reference to it.
+ // At the start of collection we flush all refinement logs, and remembered sets
+ // are completely up-to-date wrt to references to the humongous object.
+ //
+ // Other implementation considerations:
+ // - never consider object arrays at this time because they would pose
+ // considerable effort for cleaning up the the remembered sets. This is
+ // required because stale remembered sets might reference locations that
+ // are currently allocated into.
+ uint region_idx = r->hrm_index();
+ if (!g1h->is_humongous_reclaim_candidate(region_idx) ||
+ !r->rem_set()->is_empty()) {
+
+ if (G1TraceEagerReclaimHumongousObjects) {
+ gclog_or_tty->print_cr("Live humongous region %u size "SIZE_FORMAT" start "PTR_FORMAT" length %u with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d reclaim candidate %d type array %d",
+ region_idx,
+ (size_t)obj->size() * HeapWordSize,
+ p2i(r->bottom()),
+ r->region_num(),
+ r->rem_set()->occupied(),
+ r->rem_set()->strong_code_roots_list_length(),
+ next_bitmap->isMarked(r->bottom()),
+ g1h->is_humongous_reclaim_candidate(region_idx),
+ obj->is_typeArray()
+ );
+ }
+
+ return false;
+ }
+
+ guarantee(obj->is_typeArray(),
+ err_msg("Only eagerly reclaiming type arrays is supported, but the object "
+ PTR_FORMAT " is not.",
+ p2i(r->bottom())));
+
+ if (G1TraceEagerReclaimHumongousObjects) {
+ gclog_or_tty->print_cr("Dead humongous region %u size "SIZE_FORMAT" start "PTR_FORMAT" length %u with remset "SIZE_FORMAT" code roots "SIZE_FORMAT" is marked %d reclaim candidate %d type array %d",
+ region_idx,
+ (size_t)obj->size() * HeapWordSize,
+ p2i(r->bottom()),
+ r->region_num(),
+ r->rem_set()->occupied(),
+ r->rem_set()->strong_code_roots_list_length(),
+ next_bitmap->isMarked(r->bottom()),
+ g1h->is_humongous_reclaim_candidate(region_idx),
+ obj->is_typeArray()
+ );
+ }
+ // Need to clear mark bit of the humongous object if already set.
+ if (next_bitmap->isMarked(r->bottom())) {
+ next_bitmap->clear(r->bottom());
+ }
+ _freed_bytes += r->used();
+ r->set_containing_set(NULL);
+ _humongous_regions_removed.increment(1u, r->capacity());
+ g1h->free_humongous_region(r, _free_region_list, false);
+
+ return false;
+ }
+
+ HeapRegionSetCount& humongous_free_count() {
+ return _humongous_regions_removed;
+ }
+
+ size_t bytes_freed() const {
+ return _freed_bytes;
+ }
+
+ size_t humongous_reclaimed() const {
+ return _humongous_regions_removed.length();
+ }
+};
+
+void G1CollectedHeap::eagerly_reclaim_humongous_regions() {
+ assert_at_safepoint(true);
+
+ if (!G1EagerReclaimHumongousObjects ||
+ (!_has_humongous_reclaim_candidates && !G1TraceEagerReclaimHumongousObjects)) {
+ g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms(0.0, 0);
+ return;
+ }
+
+ double start_time = os::elapsedTime();
+
+ FreeRegionList local_cleanup_list("Local Humongous Cleanup List");
+
+ G1FreeHumongousRegionClosure cl(&local_cleanup_list);
+ heap_region_iterate(&cl);
+
+ HeapRegionSetCount empty_set;
+ remove_from_old_sets(empty_set, cl.humongous_free_count());
+
+ G1HRPrinter* hrp = hr_printer();
+ if (hrp->is_active()) {
+ FreeRegionListIterator iter(&local_cleanup_list);
+ while (iter.more_available()) {
+ HeapRegion* hr = iter.get_next();
+ hrp->cleanup(hr);
+ }
+ }
+
+ prepend_to_freelist(&local_cleanup_list);
+ decrement_summary_bytes(cl.bytes_freed());
+
+ g1_policy()->phase_times()->record_fast_reclaim_humongous_time_ms((os::elapsedTime() - start_time) * 1000.0,
+ cl.humongous_reclaimed());
+}
+
+// This routine is similar to the above but does not record
+// any policy statistics or update free lists; we are abandoning
+// the current incremental collection set in preparation of a
+// full collection. After the full GC we will start to build up
+// the incremental collection set again.
+// This is only called when we're doing a full collection
+// and is immediately followed by the tearing down of the young list.
+
+void G1CollectedHeap::abandon_collection_set(HeapRegion* cs_head) {
+ HeapRegion* cur = cs_head;
+
+ while (cur != NULL) {
+ HeapRegion* next = cur->next_in_collection_set();
+ assert(cur->in_collection_set(), "bad CS");
+ cur->set_next_in_collection_set(NULL);
+ clear_in_cset(cur);
+ cur->set_young_index_in_cset(-1);
+ cur = next;
+ }
+}
+
+void G1CollectedHeap::set_free_regions_coming() {
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [cm thread] : "
+ "setting free regions coming");
+ }
+
+ assert(!free_regions_coming(), "pre-condition");
+ _free_regions_coming = true;
+}
+
+void G1CollectedHeap::reset_free_regions_coming() {
+ assert(free_regions_coming(), "pre-condition");
+
+ {
+ MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
+ _free_regions_coming = false;
+ SecondaryFreeList_lock->notify_all();
+ }
+
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [cm thread] : "
+ "reset free regions coming");
+ }
+}
+
+void G1CollectedHeap::wait_while_free_regions_coming() {
+ // Most of the time we won't have to wait, so let's do a quick test
+ // first before we take the lock.
+ if (!free_regions_coming()) {
+ return;
+ }
+
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [other] : "
+ "waiting for free regions");
+ }
+
+ {
+ MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
+ while (free_regions_coming()) {
+ SecondaryFreeList_lock->wait(Mutex::_no_safepoint_check_flag);
+ }
+ }
+
+ if (G1ConcRegionFreeingVerbose) {
+ gclog_or_tty->print_cr("G1ConcRegionFreeing [other] : "
+ "done waiting for free regions");
+ }
+}
+
+void G1CollectedHeap::set_region_short_lived_locked(HeapRegion* hr) {
+ _young_list->push_region(hr);
+}
+
+class NoYoungRegionsClosure: public HeapRegionClosure {
+private:
+ bool _success;
+public:
+ NoYoungRegionsClosure() : _success(true) { }
+ bool doHeapRegion(HeapRegion* r) {
+ if (r->is_young()) {
+ gclog_or_tty->print_cr("Region ["PTR_FORMAT", "PTR_FORMAT") tagged as young",
+ p2i(r->bottom()), p2i(r->end()));
+ _success = false;
+ }
+ return false;
+ }
+ bool success() { return _success; }
+};
+
+bool G1CollectedHeap::check_young_list_empty(bool check_heap, bool check_sample) {
+ bool ret = _young_list->check_list_empty(check_sample);
+
+ if (check_heap) {
+ NoYoungRegionsClosure closure;
+ heap_region_iterate(&closure);
+ ret = ret && closure.success();
+ }
+
+ return ret;
+}
+
+class TearDownRegionSetsClosure : public HeapRegionClosure {
+private:
+ HeapRegionSet *_old_set;
+
+public:
+ TearDownRegionSetsClosure(HeapRegionSet* old_set) : _old_set(old_set) { }
+
+ bool doHeapRegion(HeapRegion* r) {
+ if (r->is_old()) {
+ _old_set->remove(r);
+ } else {
+ // We ignore free regions, we'll empty the free list afterwards.
+ // We ignore young regions, we'll empty the young list afterwards.
+ // We ignore humongous regions, we're not tearing down the
+ // humongous regions set.
+ assert(r->is_free() || r->is_young() || r->is_humongous(),
+ "it cannot be another type");
+ }
+ return false;
+ }
+
+ ~TearDownRegionSetsClosure() {
+ assert(_old_set->is_empty(), "post-condition");
+ }
+};
+
+void G1CollectedHeap::tear_down_region_sets(bool free_list_only) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+
+ if (!free_list_only) {
+ TearDownRegionSetsClosure cl(&_old_set);
+ heap_region_iterate(&cl);
+
+ // Note that emptying the _young_list is postponed and instead done as
+ // the first step when rebuilding the regions sets again. The reason for
+ // this is that during a full GC string deduplication needs to know if
+ // a collected region was young or old when the full GC was initiated.
+ }
+ _hrm.remove_all_free_regions();
+}
+
+class RebuildRegionSetsClosure : public HeapRegionClosure {
+private:
+ bool _free_list_only;
+ HeapRegionSet* _old_set;
+ HeapRegionManager* _hrm;
+ size_t _total_used;
+
+public:
+ RebuildRegionSetsClosure(bool free_list_only,
+ HeapRegionSet* old_set, HeapRegionManager* hrm) :
+ _free_list_only(free_list_only),
+ _old_set(old_set), _hrm(hrm), _total_used(0) {
+ assert(_hrm->num_free_regions() == 0, "pre-condition");
+ if (!free_list_only) {
+ assert(_old_set->is_empty(), "pre-condition");
+ }
+ }
+
+ bool doHeapRegion(HeapRegion* r) {
+ if (r->is_continues_humongous()) {
+ return false;
+ }
+
+ if (r->is_empty()) {
+ // Add free regions to the free list
+ r->set_free();
+ r->set_allocation_context(AllocationContext::system());
+ _hrm->insert_into_free_list(r);
+ } else if (!_free_list_only) {
+ assert(!r->is_young(), "we should not come across young regions");
+
+ if (r->is_humongous()) {
+ // We ignore humongous regions, we left the humongous set unchanged
+ } else {
+ // Objects that were compacted would have ended up on regions
+ // that were previously old or free.
+ assert(r->is_free() || r->is_old(), "invariant");
+ // We now consider them old, so register as such.
+ r->set_old();
+ _old_set->add(r);
+ }
+ _total_used += r->used();
+ }
+
+ return false;
+ }
+
+ size_t total_used() {
+ return _total_used;
+ }
+};
+
+void G1CollectedHeap::rebuild_region_sets(bool free_list_only) {
+ assert_at_safepoint(true /* should_be_vm_thread */);
+
+ if (!free_list_only) {
+ _young_list->empty_list();
+ }
+
+ RebuildRegionSetsClosure cl(free_list_only, &_old_set, &_hrm);
+ heap_region_iterate(&cl);
+
+ if (!free_list_only) {
+ _allocator->set_used(cl.total_used());
+ }
+ assert(_allocator->used_unlocked() == recalculate_used(),
+ err_msg("inconsistent _allocator->used_unlocked(), "
+ "value: "SIZE_FORMAT" recalculated: "SIZE_FORMAT,
+ _allocator->used_unlocked(), recalculate_used()));
+}
+
+void G1CollectedHeap::set_refine_cte_cl_concurrency(bool concurrent) {
+ _refine_cte_cl->set_concurrent(concurrent);
+}
+
+bool G1CollectedHeap::is_in_closed_subset(const void* p) const {
+ HeapRegion* hr = heap_region_containing(p);
+ return hr->is_in(p);
+}
+
+// Methods for the mutator alloc region
+
+HeapRegion* G1CollectedHeap::new_mutator_alloc_region(size_t word_size,
+ bool force) {
+ assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
+ assert(!force || g1_policy()->can_expand_young_list(),
+ "if force is true we should be able to expand the young list");
+ bool young_list_full = g1_policy()->is_young_list_full();
+ if (force || !young_list_full) {
+ HeapRegion* new_alloc_region = new_region(word_size,
+ false /* is_old */,
+ false /* do_expand */);
+ if (new_alloc_region != NULL) {
+ set_region_short_lived_locked(new_alloc_region);
+ _hr_printer.alloc(new_alloc_region, G1HRPrinter::Eden, young_list_full);
+ check_bitmaps("Mutator Region Allocation", new_alloc_region);
+ return new_alloc_region;
+ }
+ }
+ return NULL;
+}
+
+void G1CollectedHeap::retire_mutator_alloc_region(HeapRegion* alloc_region,
+ size_t allocated_bytes) {
+ assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
+ assert(alloc_region->is_eden(), "all mutator alloc regions should be eden");
+
+ g1_policy()->add_region_to_incremental_cset_lhs(alloc_region);
+ _allocator->increase_used(allocated_bytes);
+ _hr_printer.retire(alloc_region);
+ // We update the eden sizes here, when the region is retired,
+ // instead of when it's allocated, since this is the point that its
+ // used space has been recored in _summary_bytes_used.
+ g1mm()->update_eden_size();
+}
+
+void G1CollectedHeap::set_par_threads() {
+ // Don't change the number of workers. Use the value previously set
+ // in the workgroup.
+ uint n_workers = workers()->active_workers();
+ assert(UseDynamicNumberOfGCThreads ||
+ n_workers == workers()->total_workers(),
+ "Otherwise should be using the total number of workers");
+ if (n_workers == 0) {
+ assert(false, "Should have been set in prior evacuation pause.");
+ n_workers = ParallelGCThreads;
+ workers()->set_active_workers(n_workers);
+ }
+ set_par_threads(n_workers);
+}
+
+// Methods for the GC alloc regions
+
+HeapRegion* G1CollectedHeap::new_gc_alloc_region(size_t word_size,
+ uint count,
+ InCSetState dest) {
+ assert(FreeList_lock->owned_by_self(), "pre-condition");
+
+ if (count < g1_policy()->max_regions(dest)) {
+ const bool is_survivor = (dest.is_young());
+ HeapRegion* new_alloc_region = new_region(word_size,
+ !is_survivor,
+ true /* do_expand */);
+ if (new_alloc_region != NULL) {
+ // We really only need to do this for old regions given that we
+ // should never scan survivors. But it doesn't hurt to do it
+ // for survivors too.
+ new_alloc_region->record_timestamp();
+ if (is_survivor) {
+ new_alloc_region->set_survivor();
+ _hr_printer.alloc(new_alloc_region, G1HRPrinter::Survivor);
+ check_bitmaps("Survivor Region Allocation", new_alloc_region);
+ } else {
+ new_alloc_region->set_old();
+ _hr_printer.alloc(new_alloc_region, G1HRPrinter::Old);
+ check_bitmaps("Old Region Allocation", new_alloc_region);
+ }
+ bool during_im = g1_policy()->during_initial_mark_pause();
+ new_alloc_region->note_start_of_copying(during_im);
+ return new_alloc_region;
+ }
+ }
+ return NULL;
+}
+
+void G1CollectedHeap::retire_gc_alloc_region(HeapRegion* alloc_region,
+ size_t allocated_bytes,
+ InCSetState dest) {
+ bool during_im = g1_policy()->during_initial_mark_pause();
+ alloc_region->note_end_of_copying(during_im);
+ g1_policy()->record_bytes_copied_during_gc(allocated_bytes);
+ if (dest.is_young()) {
+ young_list()->add_survivor_region(alloc_region);
+ } else {
+ _old_set.add(alloc_region);
+ }
+ _hr_printer.retire(alloc_region);
+}
+
+// Heap region set verification
+
+class VerifyRegionListsClosure : public HeapRegionClosure {
+private:
+ HeapRegionSet* _old_set;
+ HeapRegionSet* _humongous_set;
+ HeapRegionManager* _hrm;
+
+public:
+ HeapRegionSetCount _old_count;
+ HeapRegionSetCount _humongous_count;
+ HeapRegionSetCount _free_count;
+
+ VerifyRegionListsClosure(HeapRegionSet* old_set,
+ HeapRegionSet* humongous_set,
+ HeapRegionManager* hrm) :
+ _old_set(old_set), _humongous_set(humongous_set), _hrm(hrm),
+ _old_count(), _humongous_count(), _free_count(){ }
+
+ bool doHeapRegion(HeapRegion* hr) {
+ if (hr->is_continues_humongous()) {
+ return false;
+ }
+
+ if (hr->is_young()) {
+ // TODO
+ } else if (hr->is_starts_humongous()) {
+ assert(hr->containing_set() == _humongous_set, err_msg("Heap region %u is starts humongous but not in humongous set.", hr->hrm_index()));
+ _humongous_count.increment(1u, hr->capacity());
+ } else if (hr->is_empty()) {
+ assert(_hrm->is_free(hr), err_msg("Heap region %u is empty but not on the free list.", hr->hrm_index()));
+ _free_count.increment(1u, hr->capacity());
+ } else if (hr->is_old()) {
+ assert(hr->containing_set() == _old_set, err_msg("Heap region %u is old but not in the old set.", hr->hrm_index()));
+ _old_count.increment(1u, hr->capacity());
+ } else {
+ ShouldNotReachHere();
+ }
+ return false;
+ }
+
+ void verify_counts(HeapRegionSet* old_set, HeapRegionSet* humongous_set, HeapRegionManager* free_list) {
+ guarantee(old_set->length() == _old_count.length(), err_msg("Old set count mismatch. Expected %u, actual %u.", old_set->length(), _old_count.length()));
+ guarantee(old_set->total_capacity_bytes() == _old_count.capacity(), err_msg("Old set capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
+ old_set->total_capacity_bytes(), _old_count.capacity()));
+
+ guarantee(humongous_set->length() == _humongous_count.length(), err_msg("Hum set count mismatch. Expected %u, actual %u.", humongous_set->length(), _humongous_count.length()));
+ guarantee(humongous_set->total_capacity_bytes() == _humongous_count.capacity(), err_msg("Hum set capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
+ humongous_set->total_capacity_bytes(), _humongous_count.capacity()));
+
+ guarantee(free_list->num_free_regions() == _free_count.length(), err_msg("Free list count mismatch. Expected %u, actual %u.", free_list->num_free_regions(), _free_count.length()));
+ guarantee(free_list->total_capacity_bytes() == _free_count.capacity(), err_msg("Free list capacity mismatch. Expected " SIZE_FORMAT ", actual " SIZE_FORMAT,
+ free_list->total_capacity_bytes(), _free_count.capacity()));
+ }
+};
+
+void G1CollectedHeap::verify_region_sets() {
+ assert_heap_locked_or_at_safepoint(true /* should_be_vm_thread */);
+
+ // First, check the explicit lists.
+ _hrm.verify();
+ {
+ // Given that a concurrent operation might be adding regions to
+ // the secondary free list we have to take the lock before
+ // verifying it.
+ MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
+ _secondary_free_list.verify_list();
+ }
+
+ // If a concurrent region freeing operation is in progress it will
+ // be difficult to correctly attributed any free regions we come
+ // across to the correct free list given that they might belong to
+ // one of several (free_list, secondary_free_list, any local lists,
+ // etc.). So, if that's the case we will skip the rest of the
+ // verification operation. Alternatively, waiting for the concurrent
+ // operation to complete will have a non-trivial effect on the GC's
+ // operation (no concurrent operation will last longer than the
+ // interval between two calls to verification) and it might hide
+ // any issues that we would like to catch during testing.
+ if (free_regions_coming()) {
+ return;
+ }
+
+ // Make sure we append the secondary_free_list on the free_list so
+ // that all free regions we will come across can be safely
+ // attributed to the free_list.
+ append_secondary_free_list_if_not_empty_with_lock();
+
+ // Finally, make sure that the region accounting in the lists is
+ // consistent with what we see in the heap.
+
+ VerifyRegionListsClosure cl(&_old_set, &_humongous_set, &_hrm);
+ heap_region_iterate(&cl);
+ cl.verify_counts(&_old_set, &_humongous_set, &_hrm);
+}
+
+// Optimized nmethod scanning
+
+class RegisterNMethodOopClosure: public OopClosure {
+ G1CollectedHeap* _g1h;
+ nmethod* _nm;
+
+ template <class T> void do_oop_work(T* p) {
+ T heap_oop = oopDesc::load_heap_oop(p);
+ if (!oopDesc::is_null(heap_oop)) {
+ oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
+ HeapRegion* hr = _g1h->heap_region_containing(obj);
+ assert(!hr->is_continues_humongous(),
+ err_msg("trying to add code root "PTR_FORMAT" in continuation of humongous region "HR_FORMAT
+ " starting at "HR_FORMAT,
+ p2i(_nm), HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region())));
+
+ // HeapRegion::add_strong_code_root_locked() avoids adding duplicate entries.
+ hr->add_strong_code_root_locked(_nm);
+ }
+ }
+
+public:
+ RegisterNMethodOopClosure(G1CollectedHeap* g1h, nmethod* nm) :
+ _g1h(g1h), _nm(nm) {}
+
+ void do_oop(oop* p) { do_oop_work(p); }
+ void do_oop(narrowOop* p) { do_oop_work(p); }
+};
+
+class UnregisterNMethodOopClosure: public OopClosure {
+ G1CollectedHeap* _g1h;
+ nmethod* _nm;
+
+ template <class T> void do_oop_work(T* p) {
+ T heap_oop = oopDesc::load_heap_oop(p);
+ if (!oopDesc::is_null(heap_oop)) {
+ oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
+ HeapRegion* hr = _g1h->heap_region_containing(obj);
+ assert(!hr->is_continues_humongous(),
+ err_msg("trying to remove code root "PTR_FORMAT" in continuation of humongous region "HR_FORMAT
+ " starting at "HR_FORMAT,
+ p2i(_nm), HR_FORMAT_PARAMS(hr), HR_FORMAT_PARAMS(hr->humongous_start_region())));
+
+ hr->remove_strong_code_root(_nm);
+ }
+ }
+
+public:
+ UnregisterNMethodOopClosure(G1CollectedHeap* g1h, nmethod* nm) :
+ _g1h(g1h), _nm(nm) {}
+
+ void do_oop(oop* p) { do_oop_work(p); }
+ void do_oop(narrowOop* p) { do_oop_work(p); }
+};
+
+void G1CollectedHeap::register_nmethod(nmethod* nm) {
+ CollectedHeap::register_nmethod(nm);
+
+ guarantee(nm != NULL, "sanity");
+ RegisterNMethodOopClosure reg_cl(this, nm);
+ nm->oops_do(®_cl);
+}
+
+void G1CollectedHeap::unregister_nmethod(nmethod* nm) {
+ CollectedHeap::unregister_nmethod(nm);
+
+ guarantee(nm != NULL, "sanity");
+ UnregisterNMethodOopClosure reg_cl(this, nm);
+ nm->oops_do(®_cl, true);
+}
+
+void G1CollectedHeap::purge_code_root_memory() {
+ double purge_start = os::elapsedTime();
+ G1CodeRootSet::purge();
+ double purge_time_ms = (os::elapsedTime() - purge_start) * 1000.0;
+ g1_policy()->phase_times()->record_strong_code_root_purge_time(purge_time_ms);
+}
+
+class RebuildStrongCodeRootClosure: public CodeBlobClosure {
+ G1CollectedHeap* _g1h;
+
+public:
+ RebuildStrongCodeRootClosure(G1CollectedHeap* g1h) :
+ _g1h(g1h) {}
+
+ void do_code_blob(CodeBlob* cb) {
+ nmethod* nm = (cb != NULL) ? cb->as_nmethod_or_null() : NULL;
+ if (nm == NULL) {
+ return;
+ }
+
+ if (ScavengeRootsInCode) {
+ _g1h->register_nmethod(nm);
+ }
+ }
+};
+
+void G1CollectedHeap::rebuild_strong_code_roots() {
+ RebuildStrongCodeRootClosure blob_cl(this);
+ CodeCache::blobs_do(&blob_cl);
+}