| /* |
| * Copyright (c) 2001, 2016, 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 "classfile/symbolTable.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/g1Allocator.inline.hpp" |
| #include "gc/g1/g1CollectedHeap.inline.hpp" |
| #include "gc/g1/g1CollectorPolicy.hpp" |
| #include "gc/g1/g1CollectorState.hpp" |
| #include "gc/g1/g1EvacStats.inline.hpp" |
| #include "gc/g1/g1GCPhaseTimes.hpp" |
| #include "gc/g1/g1HeapTransition.hpp" |
| #include "gc/g1/g1HeapVerifier.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/g1RootClosures.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/suspendibleThreadSet.hpp" |
| #include "gc/g1/vm_operations_g1.hpp" |
| #include "gc/shared/gcHeapSummary.hpp" |
| #include "gc/shared/gcId.hpp" |
| #include "gc/shared/gcLocker.inline.hpp" |
| #include "gc/shared/gcTimer.hpp" |
| #include "gc/shared/gcTrace.hpp" |
| #include "gc/shared/gcTraceTime.inline.hpp" |
| #include "gc/shared/generationSpec.hpp" |
| #include "gc/shared/isGCActiveMark.hpp" |
| #include "gc/shared/referenceProcessor.inline.hpp" |
| #include "gc/shared/taskqueue.inline.hpp" |
| #include "logging/log.hpp" |
| #include "memory/allocation.hpp" |
| #include "memory/iterator.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/atomic.inline.hpp" |
| #include "runtime/init.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; |
| |
| // 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_dirtied; |
| G1CollectedHeap* _g1h; |
| G1SATBCardTableLoggingModRefBS* _g1_bs; |
| |
| HeapRegion* region_for_card(jbyte* card_ptr) const { |
| return _g1h->heap_region_containing(_g1_bs->addr_for(card_ptr)); |
| } |
| |
| bool will_become_free(HeapRegion* hr) const { |
| // A region will be freed by free_collection_set if the region is in the |
| // collection set and has not had an evacuation failure. |
| return _g1h->is_in_cset(hr) && !hr->evacuation_failed(); |
| } |
| |
| public: |
| RedirtyLoggedCardTableEntryClosure(G1CollectedHeap* g1h) : CardTableEntryClosure(), |
| _num_dirtied(0), _g1h(g1h), _g1_bs(g1h->g1_barrier_set()) { } |
| |
| bool do_card_ptr(jbyte* card_ptr, uint worker_i) { |
| HeapRegion* hr = region_for_card(card_ptr); |
| |
| // Should only dirty cards in regions that won't be freed. |
| if (!will_become_free(hr)) { |
| *card_ptr = CardTableModRefBS::dirty_card_val(); |
| _num_dirtied++; |
| } |
| |
| return true; |
| } |
| |
| size_t num_dirtied() const { return _num_dirtied; } |
| }; |
| |
| |
| 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_pinned(); |
| } |
| |
| // 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()) { |
| log_develop_trace(gc, freelist)("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); |
| log_develop_trace(gc, freelist)("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); |
| } |
| |
| log_develop_trace(gc, freelist)("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()) { |
| log_develop_trace(gc, freelist)("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) { |
| log_develop_trace(gc, freelist)("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"); |
| |
| log_debug(gc, ergo, heap)("Attempt heap expansion (region allocation request failed). Allocation request: " SIZE_FORMAT "B", |
| 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. |
| uint last = first + num_regions - 1; |
| |
| // 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 top of the new object. |
| HeapWord* obj_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); |
| |
| // How many words we use for filler objects. |
| size_t word_fill_size = word_size_sum - word_size; |
| |
| // How many words memory we "waste" which cannot hold a filler object. |
| size_t words_not_fillable = 0; |
| |
| if (word_fill_size >= min_fill_size()) { |
| fill_with_objects(obj_top, word_fill_size); |
| } else if (word_fill_size > 0) { |
| // We have space to fill, but we cannot fit an object there. |
| words_not_fillable = word_fill_size; |
| word_fill_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(obj_top, word_fill_size); |
| 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); |
| } |
| |
| // 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, we will update the top fields of the "continues humongous" |
| // regions except the last one. |
| for (uint i = first; i < last; ++i) { |
| hr = region_at(i); |
| hr->set_top(hr->end()); |
| } |
| |
| hr = region_at(last); |
| // If we cannot fit a filler object, we must set top to the end |
| // of the humongous object, otherwise we cannot iterate the heap |
| // and the BOT will not be complete. |
| hr->set_top(hr->end() - words_not_fillable); |
| |
| assert(hr->bottom() < obj_top && obj_top <= hr->end(), |
| "obj_top should be in last region"); |
| |
| _verifier->check_bitmaps("Humongous Region Allocation", first_hr); |
| |
| assert(words_not_fillable == 0 || |
| first_hr->bottom() + word_size_sum - words_not_fillable == hr->top(), |
| "Miscalculation in humongous allocation"); |
| |
| increase_used((word_size_sum - words_not_fillable) * HeapWordSize); |
| |
| for (uint i = first; i <= last; ++i) { |
| hr = region_at(i); |
| _humongous_set.add(hr); |
| _hr_printer.alloc(hr); |
| } |
| |
| return new_obj; |
| } |
| |
| size_t G1CollectedHeap::humongous_obj_size_in_regions(size_t word_size) { |
| assert(is_humongous(word_size), "Object of size " SIZE_FORMAT " must be humongous here", word_size); |
| return align_size_up_(word_size, HeapRegion::GrainWords) / HeapRegion::GrainWords; |
| } |
| |
| // 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 */); |
| |
| _verifier->verify_region_sets_optional(); |
| |
| uint first = G1_NO_HRM_INDEX; |
| uint obj_regions = (uint) humongous_obj_size_in_regions(word_size); |
| |
| 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. |
| log_debug(gc, ergo, heap)("Attempt heap expansion (humongous allocation request failed). Allocation request: " SIZE_FORMAT "B", |
| 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(); |
| } |
| |
| _verifier->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->attempt_allocation_locked(word_size, context); |
| if (result != NULL) { |
| return result; |
| } |
| |
| if (GCLocker::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->attempt_allocation_force(word_size, context); |
| 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 (GCLocker::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. |
| GCLocker::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->attempt_allocation(word_size, context); |
| 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; |
| } |
| |
| void G1CollectedHeap::begin_archive_alloc_range() { |
| assert_at_safepoint(true /* should_be_vm_thread */); |
| if (_archive_allocator == NULL) { |
| _archive_allocator = G1ArchiveAllocator::create_allocator(this); |
| } |
| } |
| |
| bool G1CollectedHeap::is_archive_alloc_too_large(size_t word_size) { |
| // Allocations in archive regions cannot be of a size that would be considered |
| // humongous even for a minimum-sized region, because G1 region sizes/boundaries |
| // may be different at archive-restore time. |
| return word_size >= humongous_threshold_for(HeapRegion::min_region_size_in_words()); |
| } |
| |
| HeapWord* G1CollectedHeap::archive_mem_allocate(size_t word_size) { |
| assert_at_safepoint(true /* should_be_vm_thread */); |
| assert(_archive_allocator != NULL, "_archive_allocator not initialized"); |
| if (is_archive_alloc_too_large(word_size)) { |
| return NULL; |
| } |
| return _archive_allocator->archive_mem_allocate(word_size); |
| } |
| |
| void G1CollectedHeap::end_archive_alloc_range(GrowableArray<MemRegion>* ranges, |
| size_t end_alignment_in_bytes) { |
| assert_at_safepoint(true /* should_be_vm_thread */); |
| assert(_archive_allocator != NULL, "_archive_allocator not initialized"); |
| |
| // Call complete_archive to do the real work, filling in the MemRegion |
| // array with the archive regions. |
| _archive_allocator->complete_archive(ranges, end_alignment_in_bytes); |
| delete _archive_allocator; |
| _archive_allocator = NULL; |
| } |
| |
| bool G1CollectedHeap::check_archive_addresses(MemRegion* ranges, size_t count) { |
| assert(ranges != NULL, "MemRegion array NULL"); |
| assert(count != 0, "No MemRegions provided"); |
| MemRegion reserved = _hrm.reserved(); |
| for (size_t i = 0; i < count; i++) { |
| if (!reserved.contains(ranges[i].start()) || !reserved.contains(ranges[i].last())) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| bool G1CollectedHeap::alloc_archive_regions(MemRegion* ranges, size_t count) { |
| assert(!is_init_completed(), "Expect to be called at JVM init time"); |
| assert(ranges != NULL, "MemRegion array NULL"); |
| assert(count != 0, "No MemRegions provided"); |
| MutexLockerEx x(Heap_lock); |
| |
| MemRegion reserved = _hrm.reserved(); |
| HeapWord* prev_last_addr = NULL; |
| HeapRegion* prev_last_region = NULL; |
| |
| // Temporarily disable pretouching of heap pages. This interface is used |
| // when mmap'ing archived heap data in, so pre-touching is wasted. |
| FlagSetting fs(AlwaysPreTouch, false); |
| |
| // Enable archive object checking in G1MarkSweep. We have to let it know |
| // about each archive range, so that objects in those ranges aren't marked. |
| G1MarkSweep::enable_archive_object_check(); |
| |
| // For each specified MemRegion range, allocate the corresponding G1 |
| // regions and mark them as archive regions. We expect the ranges in |
| // ascending starting address order, without overlap. |
| for (size_t i = 0; i < count; i++) { |
| MemRegion curr_range = ranges[i]; |
| HeapWord* start_address = curr_range.start(); |
| size_t word_size = curr_range.word_size(); |
| HeapWord* last_address = curr_range.last(); |
| size_t commits = 0; |
| |
| guarantee(reserved.contains(start_address) && reserved.contains(last_address), |
| "MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]", |
| p2i(start_address), p2i(last_address)); |
| guarantee(start_address > prev_last_addr, |
| "Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT , |
| p2i(start_address), p2i(prev_last_addr)); |
| prev_last_addr = last_address; |
| |
| // Check for ranges that start in the same G1 region in which the previous |
| // range ended, and adjust the start address so we don't try to allocate |
| // the same region again. If the current range is entirely within that |
| // region, skip it, just adjusting the recorded top. |
| HeapRegion* start_region = _hrm.addr_to_region(start_address); |
| if ((prev_last_region != NULL) && (start_region == prev_last_region)) { |
| start_address = start_region->end(); |
| if (start_address > last_address) { |
| increase_used(word_size * HeapWordSize); |
| start_region->set_top(last_address + 1); |
| continue; |
| } |
| start_region->set_top(start_address); |
| curr_range = MemRegion(start_address, last_address + 1); |
| start_region = _hrm.addr_to_region(start_address); |
| } |
| |
| // Perform the actual region allocation, exiting if it fails. |
| // Then note how much new space we have allocated. |
| if (!_hrm.allocate_containing_regions(curr_range, &commits)) { |
| return false; |
| } |
| increase_used(word_size * HeapWordSize); |
| if (commits != 0) { |
| log_debug(gc, ergo, heap)("Attempt heap expansion (allocate archive regions). Total size: " SIZE_FORMAT "B", |
| HeapRegion::GrainWords * HeapWordSize * commits); |
| |
| } |
| |
| // Mark each G1 region touched by the range as archive, add it to the old set, |
| // and set the allocation context and top. |
| HeapRegion* curr_region = _hrm.addr_to_region(start_address); |
| HeapRegion* last_region = _hrm.addr_to_region(last_address); |
| prev_last_region = last_region; |
| |
| while (curr_region != NULL) { |
| assert(curr_region->is_empty() && !curr_region->is_pinned(), |
| "Region already in use (index %u)", curr_region->hrm_index()); |
| curr_region->set_allocation_context(AllocationContext::system()); |
| curr_region->set_archive(); |
| _hr_printer.alloc(curr_region); |
| _old_set.add(curr_region); |
| if (curr_region != last_region) { |
| curr_region->set_top(curr_region->end()); |
| curr_region = _hrm.next_region_in_heap(curr_region); |
| } else { |
| curr_region->set_top(last_address + 1); |
| curr_region = NULL; |
| } |
| } |
| |
| // Notify mark-sweep of the archive range. |
| G1MarkSweep::set_range_archive(curr_range, true); |
| } |
| return true; |
| } |
| |
| void G1CollectedHeap::fill_archive_regions(MemRegion* ranges, size_t count) { |
| assert(!is_init_completed(), "Expect to be called at JVM init time"); |
| assert(ranges != NULL, "MemRegion array NULL"); |
| assert(count != 0, "No MemRegions provided"); |
| MemRegion reserved = _hrm.reserved(); |
| HeapWord *prev_last_addr = NULL; |
| HeapRegion* prev_last_region = NULL; |
| |
| // For each MemRegion, create filler objects, if needed, in the G1 regions |
| // that contain the address range. The address range actually within the |
| // MemRegion will not be modified. That is assumed to have been initialized |
| // elsewhere, probably via an mmap of archived heap data. |
| MutexLockerEx x(Heap_lock); |
| for (size_t i = 0; i < count; i++) { |
| HeapWord* start_address = ranges[i].start(); |
| HeapWord* last_address = ranges[i].last(); |
| |
| assert(reserved.contains(start_address) && reserved.contains(last_address), |
| "MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]", |
| p2i(start_address), p2i(last_address)); |
| assert(start_address > prev_last_addr, |
| "Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT , |
| p2i(start_address), p2i(prev_last_addr)); |
| |
| HeapRegion* start_region = _hrm.addr_to_region(start_address); |
| HeapRegion* last_region = _hrm.addr_to_region(last_address); |
| HeapWord* bottom_address = start_region->bottom(); |
| |
| // Check for a range beginning in the same region in which the |
| // previous one ended. |
| if (start_region == prev_last_region) { |
| bottom_address = prev_last_addr + 1; |
| } |
| |
| // Verify that the regions were all marked as archive regions by |
| // alloc_archive_regions. |
| HeapRegion* curr_region = start_region; |
| while (curr_region != NULL) { |
| guarantee(curr_region->is_archive(), |
| "Expected archive region at index %u", curr_region->hrm_index()); |
| if (curr_region != last_region) { |
| curr_region = _hrm.next_region_in_heap(curr_region); |
| } else { |
| curr_region = NULL; |
| } |
| } |
| |
| prev_last_addr = last_address; |
| prev_last_region = last_region; |
| |
| // Fill the memory below the allocated range with dummy object(s), |
| // if the region bottom does not match the range start, or if the previous |
| // range ended within the same G1 region, and there is a gap. |
| if (start_address != bottom_address) { |
| size_t fill_size = pointer_delta(start_address, bottom_address); |
| G1CollectedHeap::fill_with_objects(bottom_address, fill_size); |
| increase_used(fill_size * HeapWordSize); |
| } |
| } |
| } |
| |
| inline HeapWord* G1CollectedHeap::attempt_allocation(size_t word_size, |
| uint* gc_count_before_ret, |
| uint* gclocker_retry_count_ret) { |
| assert_heap_not_locked_and_not_at_safepoint(); |
| assert(!is_humongous(word_size), "attempt_allocation() should not " |
| "be called for humongous allocation requests"); |
| |
| AllocationContext_t context = AllocationContext::current(); |
| HeapWord* result = _allocator->attempt_allocation(word_size, context); |
| |
| if (result == NULL) { |
| result = attempt_allocation_slow(word_size, |
| context, |
| gc_count_before_ret, |
| gclocker_retry_count_ret); |
| } |
| assert_heap_not_locked(); |
| if (result != NULL) { |
| dirty_young_block(result, word_size); |
| } |
| return result; |
| } |
| |
| void G1CollectedHeap::dealloc_archive_regions(MemRegion* ranges, size_t count) { |
| assert(!is_init_completed(), "Expect to be called at JVM init time"); |
| assert(ranges != NULL, "MemRegion array NULL"); |
| assert(count != 0, "No MemRegions provided"); |
| MemRegion reserved = _hrm.reserved(); |
| HeapWord* prev_last_addr = NULL; |
| HeapRegion* prev_last_region = NULL; |
| size_t size_used = 0; |
| size_t uncommitted_regions = 0; |
| |
| // For each Memregion, free the G1 regions that constitute it, and |
| // notify mark-sweep that the range is no longer to be considered 'archive.' |
| MutexLockerEx x(Heap_lock); |
| for (size_t i = 0; i < count; i++) { |
| HeapWord* start_address = ranges[i].start(); |
| HeapWord* last_address = ranges[i].last(); |
| |
| assert(reserved.contains(start_address) && reserved.contains(last_address), |
| "MemRegion outside of heap [" PTR_FORMAT ", " PTR_FORMAT "]", |
| p2i(start_address), p2i(last_address)); |
| assert(start_address > prev_last_addr, |
| "Ranges not in ascending order: " PTR_FORMAT " <= " PTR_FORMAT , |
| p2i(start_address), p2i(prev_last_addr)); |
| size_used += ranges[i].byte_size(); |
| prev_last_addr = last_address; |
| |
| HeapRegion* start_region = _hrm.addr_to_region(start_address); |
| HeapRegion* last_region = _hrm.addr_to_region(last_address); |
| |
| // Check for ranges that start in the same G1 region in which the previous |
| // range ended, and adjust the start address so we don't try to free |
| // the same region again. If the current range is entirely within that |
| // region, skip it. |
| if (start_region == prev_last_region) { |
| start_address = start_region->end(); |
| if (start_address > last_address) { |
| continue; |
| } |
| start_region = _hrm.addr_to_region(start_address); |
| } |
| prev_last_region = last_region; |
| |
| // After verifying that each region was marked as an archive region by |
| // alloc_archive_regions, set it free and empty and uncommit it. |
| HeapRegion* curr_region = start_region; |
| while (curr_region != NULL) { |
| guarantee(curr_region->is_archive(), |
| "Expected archive region at index %u", curr_region->hrm_index()); |
| uint curr_index = curr_region->hrm_index(); |
| _old_set.remove(curr_region); |
| curr_region->set_free(); |
| curr_region->set_top(curr_region->bottom()); |
| if (curr_region != last_region) { |
| curr_region = _hrm.next_region_in_heap(curr_region); |
| } else { |
| curr_region = NULL; |
| } |
| _hrm.shrink_at(curr_index, 1); |
| uncommitted_regions++; |
| } |
| |
| // Notify mark-sweep that this is no longer an archive range. |
| G1MarkSweep::set_range_archive(ranges[i], false); |
| } |
| |
| if (uncommitted_regions != 0) { |
| log_debug(gc, ergo, heap)("Attempt heap shrinking (uncommitted archive regions). Total size: " SIZE_FORMAT "B", |
| HeapRegion::GrainWords * HeapWordSize * uncommitted_regions); |
| } |
| decrease_used(size_used); |
| } |
| |
| 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) { |
| size_t size_in_regions = humongous_obj_size_in_regions(word_size); |
| g1_policy()->add_bytes_allocated_in_old_since_last_gc(size_in_regions * HeapRegion::GrainBytes); |
| return result; |
| } |
| |
| if (GCLocker::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 (GCLocker::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. |
| GCLocker::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->has_mutator_alloc_region(context) || !expect_null_mutator_alloc_region, |
| "the current alloc region was unexpectedly found to be non-NULL"); |
| |
| if (!is_humongous(word_size)) { |
| return _allocator->attempt_allocation_locked(word_size, context); |
| } else { |
| HeapWord* result = humongous_obj_allocate(word_size, context); |
| if (result != NULL && g1_policy()->need_to_start_conc_mark("STW humongous allocation")) { |
| collector_state()->set_initiate_conc_mark_if_possible(true); |
| } |
| 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(); |
| |
| _g1h->reset_gc_time_stamps(r); |
| |
| 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"); |
| } else { |
| 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"); |
| _hr_printer->post_compaction(hr); |
| return false; |
| } |
| |
| PostCompactionPrinterClosure(G1HRPrinter* hr_printer) |
| : _hr_printer(hr_printer) { } |
| }; |
| |
| void G1CollectedHeap::print_hrm_post_compaction() { |
| if (_hr_printer.is_active()) { |
| PostCompactionPrinterClosure cl(hr_printer()); |
| heap_region_iterate(&cl); |
| } |
| |
| } |
| |
| bool G1CollectedHeap::do_full_collection(bool explicit_gc, |
| bool clear_all_soft_refs) { |
| assert_at_safepoint(true /* should_be_vm_thread */); |
| |
| if (GCLocker::check_active_before_gc()) { |
| return false; |
| } |
| |
| STWGCTimer* gc_timer = G1MarkSweep::gc_timer(); |
| gc_timer->register_gc_start(); |
| |
| SerialOldTracer* gc_tracer = G1MarkSweep::gc_tracer(); |
| GCIdMark gc_id_mark; |
| gc_tracer->report_gc_start(gc_cause(), gc_timer->gc_start()); |
| |
| SvcGCMarker sgcm(SvcGCMarker::FULL); |
| ResourceMark rm; |
| |
| print_heap_before_gc(); |
| trace_heap_before_gc(gc_tracer); |
| |
| size_t metadata_prev_used = MetaspaceAux::used_bytes(); |
| |
| _verifier->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(!GCCause::is_user_requested_gc(gc_cause()) || explicit_gc, "invariant"); |
| GCTraceCPUTime tcpu; |
| |
| { |
| GCTraceTime(Info, gc) tm("Pause Full", NULL, gc_cause(), true); |
| TraceCollectorStats tcs(g1mm()->full_collection_counters()); |
| TraceMemoryManagerStats tms(true /* fullGC */, gc_cause()); |
| |
| G1HeapTransition heap_transition(this); |
| 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"); |
| |
| _verifier->verify_before_gc(); |
| |
| _verifier->check_bitmaps("Full GC Start"); |
| pre_full_gc_dump(gc_timer); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::clear(); |
| #endif |
| |
| // 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. |
| 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 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 */); |
| collector_state()->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(); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::update_pointers(); |
| #endif |
| |
| 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_if_necessary_after_full_collection(); |
| |
| // We should do this after we potentially resize the heap so |
| // that all the COMMIT / UNCOMMIT events are generated before |
| // the compaction events. |
| print_hrm_post_compaction(); |
| |
| 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()); |
| workers()->set_active_workers(n_workers); |
| |
| ParRebuildRSTask rebuild_rs_task(this); |
| workers()->run_task(&rebuild_rs_task); |
| |
| // 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"); |
| |
| // 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(); |
| _verifier->verify_region_sets_optional(); |
| |
| _verifier->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 |
| // G1ConcurrentMark::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) { |
| ((G1CMBitMap*) concurrent_mark()->prevMarkBitMap())->clearAll(); |
| } |
| _verifier->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(); |
| |
| // 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); |
| |
| heap_transition.print(); |
| |
| 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) { |
| // Currently, there is no facility in the do_full_collection(bool) API to notify |
| // the caller that 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_full_collection(true, /* explicit_gc */ |
| clear_all_soft_refs); |
| } |
| |
| void G1CollectedHeap::resize_if_necessary_after_full_collection() { |
| // Include 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, |
| "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; |
| |
| log_debug(gc, ergo, heap)("Attempt heap expansion (capacity lower than min desired capacity after Full GC). " |
| "Capacity: " SIZE_FORMAT "B occupancy: " SIZE_FORMAT "B min_desired_capacity: " SIZE_FORMAT "B (" UINTX_FORMAT " %%)", |
| capacity_after_gc, used_after_gc, minimum_desired_capacity, 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; |
| |
| log_debug(gc, ergo, heap)("Attempt heap shrinking (capacity higher than max desired capacity after Full GC). " |
| "Capacity: " SIZE_FORMAT "B occupancy: " SIZE_FORMAT "B min_desired_capacity: " SIZE_FORMAT "B (" UINTX_FORMAT " %%)", |
| capacity_after_gc, used_after_gc, minimum_desired_capacity, MinHeapFreeRatio); |
| |
| shrink(shrink_bytes); |
| } |
| } |
| |
| HeapWord* G1CollectedHeap::satisfy_failed_allocation_helper(size_t word_size, |
| AllocationContext_t context, |
| bool do_gc, |
| bool clear_all_soft_refs, |
| bool expect_null_mutator_alloc_region, |
| bool* gc_succeeded) { |
| *gc_succeeded = true; |
| // Let's attempt the allocation first. |
| HeapWord* result = |
| attempt_allocation_at_safepoint(word_size, |
| context, |
| expect_null_mutator_alloc_region); |
| if (result != NULL) { |
| assert(*gc_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(*gc_succeeded, "sanity"); |
| return result; |
| } |
| |
| if (do_gc) { |
| // Expansion didn't work, we'll try to do a Full GC. |
| *gc_succeeded = do_full_collection(false, /* explicit_gc */ |
| clear_all_soft_refs); |
| } |
| |
| return NULL; |
| } |
| |
| HeapWord* G1CollectedHeap::satisfy_failed_allocation(size_t word_size, |
| AllocationContext_t context, |
| bool* succeeded) { |
| assert_at_safepoint(true /* should_be_vm_thread */); |
| |
| // Attempts to allocate followed by Full GC. |
| HeapWord* result = |
| satisfy_failed_allocation_helper(word_size, |
| context, |
| true, /* do_gc */ |
| false, /* clear_all_soft_refs */ |
| false, /* expect_null_mutator_alloc_region */ |
| succeeded); |
| |
| if (result != NULL || !*succeeded) { |
| return result; |
| } |
| |
| // Attempts to allocate followed by Full GC that will collect all soft references. |
| result = satisfy_failed_allocation_helper(word_size, |
| context, |
| true, /* do_gc */ |
| true, /* clear_all_soft_refs */ |
| true, /* expect_null_mutator_alloc_region */ |
| succeeded); |
| |
| if (result != NULL || !*succeeded) { |
| return result; |
| } |
| |
| // Attempts to allocate, no GC |
| result = satisfy_failed_allocation_helper(word_size, |
| context, |
| false, /* do_gc */ |
| false, /* clear_all_soft_refs */ |
| true, /* expect_null_mutator_alloc_region */ |
| succeeded); |
| |
| 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 */); |
| |
| _verifier->verify_region_sets_optional(); |
| |
| size_t expand_bytes = MAX2(word_size * HeapWordSize, MinHeapDeltaBytes); |
| log_debug(gc, ergo, heap)("Attempt heap expansion (allocation request failed). Allocation request: " SIZE_FORMAT "B", |
| word_size * HeapWordSize); |
| |
| |
| if (expand(expand_bytes)) { |
| _hrm.verify_optional(); |
| _verifier->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, double* expand_time_ms) { |
| size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes); |
| aligned_expand_bytes = align_size_up(aligned_expand_bytes, |
| HeapRegion::GrainBytes); |
| |
| log_debug(gc, ergo, heap)("Expand the heap. requested expansion amount:" SIZE_FORMAT "B expansion amount:" SIZE_FORMAT "B", |
| expand_bytes, aligned_expand_bytes); |
| |
| if (is_maximal_no_gc()) { |
| log_debug(gc, ergo, heap)("Did not expand the heap (heap already fully expanded)"); |
| return false; |
| } |
| |
| double expand_heap_start_time_sec = os::elapsedTime(); |
| 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 (expand_time_ms != NULL) { |
| *expand_time_ms = (os::elapsedTime() - expand_heap_start_time_sec) * MILLIUNITS; |
| } |
| |
| 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 { |
| log_debug(gc, ergo, heap)("Did not expand the heap (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; |
| |
| |
| log_debug(gc, ergo, heap)("Shrink the heap. requested shrinking amount: " SIZE_FORMAT "B aligned shrinking amount: " SIZE_FORMAT "B attempted shrinking amount: " SIZE_FORMAT "B", |
| shrink_bytes, aligned_shrink_bytes, shrunk_bytes); |
| if (num_regions_removed > 0) { |
| g1_policy()->record_new_heap_size(num_regions()); |
| } else { |
| log_debug(gc, ergo, heap)("Did not expand the heap (heap shrinking operation failed)"); |
| } |
| } |
| |
| void G1CollectedHeap::shrink(size_t shrink_bytes) { |
| _verifier->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(); |
| _verifier->verify_region_sets_optional(); |
| } |
| |
| // Public methods. |
| |
| G1CollectedHeap::G1CollectedHeap(G1CollectorPolicy* policy_) : |
| CollectedHeap(), |
| _g1_policy(policy_), |
| _dirty_card_queue_set(false), |
| _is_alive_closure_cm(this), |
| _is_alive_closure_stw(this), |
| _ref_processor_cm(NULL), |
| _ref_processor_stw(NULL), |
| _bot(NULL), |
| _cg1r(NULL), |
| _g1mm(NULL), |
| _refine_cte_cl(NULL), |
| _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), |
| _archive_allocator(NULL), |
| _free_regions_coming(false), |
| _young_list(new YoungList(this)), |
| _gc_time_stamp(0), |
| _summary_bytes_used(0), |
| _survivor_evac_stats("Young", YoungPLABSize, PLABWeight), |
| _old_evac_stats("Old", OldPLABSize, PLABWeight), |
| _expand_heap_after_alloc_failure(true), |
| _old_marking_cycles_started(0), |
| _old_marking_cycles_completed(0), |
| _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 WorkGang("GC Thread", ParallelGCThreads, |
| /* are_GC_task_threads */true, |
| /* are_ConcurrentGC_threads */false); |
| _workers->initialize_workers(); |
| _verifier = new G1HeapVerifier(this); |
| |
| _allocator = G1Allocator::create_allocator(this); |
| _humongous_object_threshold_in_words = humongous_threshold_for(HeapRegion::GrainWords); |
| |
| // Override the default _filler_array_max_size so that no humongous filler |
| // objects are created. |
| _filler_array_max_size = _humongous_object_threshold_in_words; |
| |
| uint n_queues = ParallelGCThreads; |
| _task_queues = new RefToScanQueueSet(n_queues); |
| |
| _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 (uint 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) { |
| 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(); |
| |
| // Necessary to satisfy locking discipline assertions. |
| |
| MutexLocker x(Heap_lock); |
| |
| // 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(); |
| |
| jint ecode = JNI_OK; |
| _cg1r = ConcurrentG1Refine::create(this, _refine_cte_cl, &ecode); |
| if (_cg1r == NULL) { |
| return ecode; |
| } |
| |
| // 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", |
| G1BlockOffsetTable::compute_size(g1_rs.size() / HeapWordSize), |
| G1BlockOffsetTable::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 = G1CMBitMap::compute_size(g1_rs.size()); |
| G1RegionToSpaceMapper* prev_bitmap_storage = |
| create_aux_memory_mapper("Prev Bitmap", bitmap_size, G1CMBitMap::heap_map_factor()); |
| G1RegionToSpaceMapper* next_bitmap_storage = |
| create_aux_memory_mapper("Next Bitmap", bitmap_size, G1CMBitMap::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"); |
| |
| G1RemSet::initialize(max_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 = new G1BlockOffsetTable(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 G1ConcurrentMark data structure and thread. |
| // (Must do this late, so that "max_regions" is defined.) |
| _cm = new G1ConcurrentMark(this, prev_bitmap_storage, next_bitmap_storage); |
| if (_cm == NULL || !_cm->completed_initialization()) { |
| vm_shutdown_during_initialization("Could not create/initialize G1ConcurrentMark"); |
| return JNI_ENOMEM; |
| } |
| _cmThread = _cm->cmThread(); |
| |
| // 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, |
| (int)concurrent_g1_refine()->yellow_zone(), |
| (int)concurrent_g1_refine()->red_zone(), |
| Shared_DirtyCardQ_lock, |
| NULL, // fl_owner |
| true); // init_free_ids |
| |
| 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(); |
| |
| _preserved_objs = NEW_C_HEAP_ARRAY(OopAndMarkOopStack, ParallelGCThreads, mtGC); |
| for (uint i = 0; i < ParallelGCThreads; i++) { |
| new (&_preserved_objs[i]) OopAndMarkOopStack(); |
| } |
| |
| 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. logging) |
| // 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 |
| ParallelGCThreads, |
| // degree of mt processing |
| (ParallelGCThreads > 1) || (ConcGCThreads > 1), |
| // mt discovery |
| 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 |
| ParallelGCThreads, |
| // degree of mt processing |
| (ParallelGCThreads > 1), |
| // mt discovery |
| ParallelGCThreads, |
| // degree of mt discovery |
| true, |
| // Reference discovery is atomic |
| &_is_alive_closure_stw); |
| // is alive closure |
| // (for efficiency/performance) |
| } |
| |
| CollectorPolicy* G1CollectedHeap::collector_policy() const { |
| return g1_policy(); |
| } |
| |
| size_t G1CollectedHeap::capacity() const { |
| return _hrm.length() * HeapRegion::GrainBytes; |
| } |
| |
| void G1CollectedHeap::reset_gc_time_stamps(HeapRegion* hr) { |
| hr->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) { |
| log_error(gc, verify)("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_hcc_closure(CardTableEntryClosure* cl, uint worker_i) { |
| _cg1r->hot_card_cache()->drain(cl, worker_i); |
| } |
| |
| void G1CollectedHeap::iterate_dirty_card_closure(CardTableEntryClosure* cl, uint worker_i) { |
| 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 { |
| size_t result = _summary_bytes_used + _allocator->used_in_alloc_regions(); |
| if (_archive_allocator != NULL) { |
| result += _archive_allocator->used(); |
| } |
| return result; |
| } |
| |
| size_t G1CollectedHeap::used_unlocked() const { |
| return _summary_bytes_used; |
| } |
| |
| class SumUsedClosure: public HeapRegionClosure { |
| size_t _used; |
| public: |
| SumUsedClosure() : _used(0) {} |
| bool doHeapRegion(HeapRegion* r) { |
| _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::is_user_requested_concurrent_full_gc(GCCause::Cause cause) { |
| switch (cause) { |
| case GCCause::_java_lang_system_gc: return ExplicitGCInvokesConcurrent; |
| case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent; |
| case GCCause::_update_allocation_context_stats_inc: return true; |
| case GCCause::_wb_conc_mark: return true; |
| default : return false; |
| } |
| } |
| |
| bool G1CollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { |
| switch (cause) { |
| case GCCause::_gc_locker: return GCLockerInvokesConcurrent; |
| case GCCause::_g1_humongous_allocation: return true; |
| default: return is_user_requested_concurrent_full_gc(cause); |
| } |
| } |
| |
| #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"); |
| |
| // _filler_array_max_size is set to humongous object threshold |
| // but temporarily change it to use CollectedHeap::fill_with_object(). |
| SizeTFlagSetting fs(_filler_array_max_size, word_size); |
| |
| 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, |
| "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), |
| "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), |
| "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->set_idle(); |
| } |
| |
| // 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) { |
| GCIdMarkAndRestore conc_gc_id_mark; |
| collector_state()->set_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); |
| _cmThread->set_gc_id(GCId::current()); |
| } |
| |
| void G1CollectedHeap::register_concurrent_cycle_end() { |
| if (collector_state()->concurrent_cycle_started()) { |
| GCIdMarkAndRestore conc_gc_id_mark(_cmThread->gc_id()); |
| if (_cm->has_aborted()) { |
| _gc_tracer_cm->report_concurrent_mode_failure(); |
| |
| // ConcurrentGCTimer will be ended as well. |
| _cm->register_concurrent_gc_end_and_stop_timer(); |
| } else { |
| _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. |
| collector_state()->set_concurrent_cycle_started(false); |
| _heap_summary_sent = false; |
| } |
| } |
| |
| void G1CollectedHeap::trace_heap_after_concurrent_cycle() { |
| if (collector_state()->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) { |
| GCIdMarkAndRestore conc_gc_id_mark(_cmThread->gc_id()); |
| trace_heap_after_gc(_gc_tracer_cm); |
| _heap_summary_sent = true; |
| } |
| } |
| } |
| |
| 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 (GCLocker::is_active_and_needs_gc()) { |
| GCLocker::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() should successfully |
| // return the containing region. |
| HeapRegion* hr = heap_region_containing(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 |
| |
| bool G1CollectedHeap::obj_in_cs(oop obj) { |
| HeapRegion* r = _hrm.addr_to_region((HeapWord*) obj); |
| return r != NULL && r->in_collection_set(); |
| } |
| |
| // 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"); |
| |
| for (uint i = 0; i < ParallelGCThreads; 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(); |
| |
| 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; |
| OrderAccess::loadload(); |
| 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_pinned()) { |
| 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 equal to the humongous object limit. |
| size_t G1CollectedHeap::max_tlab_size() const { |
| return align_size_down(_humongous_object_threshold_in_words, MinObjAlignment); |
| } |
| |
| size_t G1CollectedHeap::unsafe_max_tlab_alloc(Thread* ignored) const { |
| AllocationContext_t context = AllocationContext::current(); |
| return _allocator->unsafe_max_tlab_alloc(context); |
| } |
| |
| 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() { |
| _verifier->prepare_for_verify(); |
| } |
| |
| void G1CollectedHeap::verify(VerifyOption vo) { |
| _verifier->verify(vo); |
| } |
| |
| 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() && !hr->is_archive(); |
| 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: { |
| HeapRegion* hr = _hrm.addr_to_region((HeapWord*)obj); |
| return !obj->is_gc_marked() && !hr->is_archive(); |
| } |
| 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: E=young(eden), S=young(survivor), O=old, " |
| "HS=humongous(starts), HC=humongous(continues), " |
| "CS=collection set, F=free, A=archive, TS=gc time stamp, " |
| "AC=allocation context, " |
| "TAMS=top-at-mark-start (previous, next)"); |
| 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 { |
| g1_rem_set()->print_summary_info(); |
| 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; |
| |
| tty->print_cr("Printing RSet for region " HR_FORMAT, HR_FORMAT_PARAMS(r)); |
| if (occupied == 0) { |
| tty->print_cr(" RSet is empty"); |
| } else { |
| hrrs->print(); |
| } |
| tty->print_cr("----------"); |
| return false; |
| } |
| |
| PrintRSetsClosure(const char* msg) : _msg(msg), _occupied_sum(0) { |
| tty->cr(); |
| tty->print_cr("========================================"); |
| tty->print_cr("%s", msg); |
| tty->cr(); |
| } |
| |
| ~PrintRSetsClosure() { |
| tty->print_cr("Occupied Sum: " SIZE_FORMAT, _occupied_sum); |
| tty->print_cr("========================================"); |
| 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 |
| |
| G1HeapSummary G1CollectedHeap::create_g1_heap_summary() { |
| YoungList* young_list = heap()->young_list(); |
| |
| size_t eden_used_bytes = young_list->eden_used_bytes(); |
| size_t survivor_used_bytes = young_list->survivor_used_bytes(); |
| |
| size_t eden_capacity_bytes = |
| (g1_policy()->young_list_target_length() * HeapRegion::GrainBytes) - survivor_used_bytes; |
| |
| VirtualSpaceSummary heap_summary = create_heap_space_summary(); |
| return G1HeapSummary(heap_summary, used(), eden_used_bytes, eden_capacity_bytes, survivor_used_bytes, num_regions()); |
| } |
| |
| G1EvacSummary G1CollectedHeap::create_g1_evac_summary(G1EvacStats* stats) { |
| return G1EvacSummary(stats->allocated(), stats->wasted(), stats->undo_wasted(), |
| stats->unused(), stats->used(), stats->region_end_waste(), |
| stats->regions_filled(), stats->direct_allocated(), |
| stats->failure_used(), stats->failure_waste()); |
| } |
| |
| void G1CollectedHeap::trace_heap(GCWhen::Type when, const GCTracer* gc_tracer) { |
| const G1HeapSummary& heap_summary = create_g1_heap_summary(); |
| gc_tracer->report_gc_heap_summary(when, heap_summary); |
| |
| const MetaspaceSummary& metaspace_summary = create_metaspace_summary(); |
| gc_tracer->report_metaspace_summary(when, metaspace_summary); |
| } |
| |
| |
| 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); |
| |
| g1_rem_set()->print_periodic_summary_info("Before GC RS summary", total_collections()); |
| } |
| |
| void G1CollectedHeap::gc_epilogue(bool full) { |
| // we are at the end of the GC. Total collections has already been increased. |
| g1_rem_set()->print_periodic_summary_info("After GC RS summary", total_collections() - 1); |
| |
| // FIXME: what is this about? |
| // I'm ignoring the "fill_newgen()" call if "alloc_event_enabled" |
| // is set. |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| assert(DerivedPointerTable::is_empty(), "derived pointer present"); |
| #endif |
| // 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(); |
| 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; |
| } |
| |
| 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->is_in_closed_subset(bs->addr_for(card_ptr))) { |
| if (*card_ptr != CardTableModRefBS::dirty_card_val()) { |
| *card_ptr = CardTableModRefBS::dirty_card_val(); |
| _dcq.enqueue(card_ptr); |
| } |
| } |
| } |
| assert(hrrs.n_yielded() == r->rem_set()->occupied(), |
| "Remembered set hash maps out of sync, cur: " SIZE_FORMAT " entries, next: " SIZE_FORMAT " entries", |
| hrrs.n_yielded(), r->rem_set()->occupied()); |
| 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(); |
| } |
| |
| class VerifyRegionRemSetClosure : public HeapRegionClosure { |
| public: |
| bool doHeapRegion(HeapRegion* hr) { |
| if (!hr->is_archive() && !hr->is_continues_humongous()) { |
| hr->verify_rem_set(); |
| } |
| return false; |
| } |
| }; |
| |
| #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 |
| |
| uint G1CollectedHeap::num_task_queues() const { |
| return _task_queues->size(); |
| } |
| |
| #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() const { |
| if (!log_develop_is_enabled(Trace, gc, task, stats)) { |
| return; |
| } |
| LogHandle(gc, task, stats) log; |
| ResourceMark rm; |
| outputStream* st = log.trace_stream(); |
| |
| print_taskqueue_stats_hdr(st); |
| |
| TaskQueueStats totals; |
| const uint n = num_task_queues(); |
| 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 = num_task_queues(); |
| for (uint i = 0; i < n; ++i) { |
| task_queue(i)->stats.reset(); |
| } |
| } |
| #endif // TASKQUEUE_STATS |
| |
| void G1CollectedHeap::wait_for_root_region_scanning() { |
| 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); |
| } |
| |
| 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 (GCLocker::check_active_before_gc()) { |
| return false; |
| } |
| |
| _gc_timer_stw->register_gc_start(); |
| |
| GCIdMark gc_id_mark; |
| _gc_tracer_stw->report_gc_start(gc_cause(), _gc_timer_stw->gc_start()); |
| |
| SvcGCMarker sgcm(SvcGCMarker::MINOR); |
| ResourceMark rm; |
| |
| wait_for_root_region_scanning(); |
| |
| print_heap_before_gc(); |
| trace_heap_before_gc(_gc_tracer_stw); |
| |
| _verifier->verify_region_sets_optional(); |
| _verifier->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(!collector_state()->during_initial_mark_pause() || |
| collector_state()->gcs_are_young(), "sanity"); |
| |
| // We also do not allow mixed GCs during marking. |
| assert(!collector_state()->mark_in_progress() || collector_state()->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 = collector_state()->during_initial_mark_pause(); |
| |
| // Inner scope for scope based logging, timers, and stats collection |
| { |
| EvacuationInfo evacuation_info; |
| |
| if (collector_state()->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(collector_state()->yc_type()); |
| |
| GCTraceCPUTime tcpu; |
| |
| FormatBuffer<> gc_string("Pause "); |
| if (collector_state()->during_initial_mark_pause()) { |
| gc_string.append("Initial Mark"); |
| } else if (collector_state()->gcs_are_young()) { |
| gc_string.append("Young"); |
| } else { |
| gc_string.append("Mixed"); |
| } |
| GCTraceTime(Info, gc) tm(gc_string, NULL, gc_cause(), true); |
| |
| uint active_workers = AdaptiveSizePolicy::calc_active_workers(workers()->total_workers(), |
| workers()->active_workers(), |
| Threads::number_of_non_daemon_threads()); |
| workers()->set_active_workers(active_workers); |
| |
| g1_policy()->note_gc_start(active_workers); |
| |
| 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(); |
| } |
| |
| G1HeapTransition heap_transition(this); |
| size_t heap_used_bytes_before_gc = used(); |
| |
| 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(); |
| |
| if (VerifyRememberedSets) { |
| log_info(gc, verify)("[Verifying RemSets before GC]"); |
| VerifyRegionRemSetClosure v_cl; |
| heap_region_iterate(&v_cl); |
| } |
| |
| _verifier->verify_before_gc(); |
| |
| _verifier->check_bitmaps("GC Start"); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::clear(); |
| #endif |
| |
| // 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 |
| if (g1_policy()->should_process_references()) { |
| ref_processor_stw()->enable_discovery(); |
| } else { |
| ref_processor_stw()->disable_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(); |
| |
| // 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(); |
| |
| g1_policy()->record_collection_pause_start(sample_start_time_sec); |
| |
| if (collector_state()->during_initial_mark_pause()) { |
| concurrent_mark()->checkpointRootsInitialPre(); |
| } |
| |
| double time_remaining_ms = g1_policy()->finalize_young_cset_part(target_pause_time_ms); |
| g1_policy()->finalize_old_cset_part(time_remaining_ms); |
| |
| evacuation_info.set_collectionset_regions(g1_policy()->cset_region_length()); |
| |
| // Make sure the remembered sets are up to date. This needs to be |
| // done before register_humongous_regions_with_cset(), because the |
| // remembered sets are used there to choose eager reclaim candidates. |
| // If the remembered sets are not up to date we might miss some |
| // entries that need to be handled. |
| g1_rem_set()->cleanupHRRS(); |
| |
| register_humongous_regions_with_cset(); |
| |
| assert(_verifier->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 |
| |
| // Initialize the GC alloc regions. |
| _allocator->init_gc_alloc_regions(evacuation_info); |
| |
| G1ParScanThreadStateSet per_thread_states(this, workers()->active_workers(), g1_policy()->young_cset_region_length()); |
| pre_evacuate_collection_set(); |
| |
| // Actually do the work... |
| evacuate_collection_set(evacuation_info, &per_thread_states); |
| |
| post_evacuate_collection_set(evacuation_info, &per_thread_states); |
| |
| const size_t* surviving_young_words = per_thread_states.surviving_young_words(); |
| free_collection_set(g1_policy()->collection_set(), evacuation_info, surviving_young_words); |
| |
| eagerly_reclaim_humongous_regions(); |
| |
| g1_policy()->clear_collection_set(); |
| |
| record_obj_copy_mem_stats(); |
| _survivor_evac_stats.adjust_desired_plab_sz(); |
| _old_evac_stats.adjust_desired_plab_sz(); |
| |
| // Start a new incremental collection set for the next pause. |
| g1_policy()->start_incremental_cset_building(); |
| |
| clear_cset_fast_test(); |
| |
| // 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"); |
| |
| 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()) { |
| set_used(recalculate_used()); |
| if (_archive_allocator != NULL) { |
| _archive_allocator->clear_used(); |
| } |
| for (uint i = 0; i < ParallelGCThreads; 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. |
| increase_used(g1_policy()->bytes_copied_during_gc()); |
| } |
| |
| if (collector_state()->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(); |
| collector_state()->set_mark_in_progress(true); |
| // 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(); |
| |
| _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 logging here, |
| // expansion_amount() does this when it returns a value > 0. |
| double expand_ms; |
| if (!expand(expand_bytes, &expand_ms)) { |
| // We failed to expand the heap. Cannot do anything about it. |
| } |
| g1_policy()->phase_times()->record_expand_heap_time(expand_ms); |
| } |
| } |
| |
| // 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; |
| size_t total_cards_scanned = per_thread_states.total_cards_scanned(); |
| g1_policy()->record_collection_pause_end(pause_time_ms, total_cards_scanned, heap_used_bytes_before_gc); |
| |
| evacuation_info.set_collectionset_used_before(g1_policy()->collection_set_bytes_used_before()); |
| evacuation_info.set_bytes_copied(g1_policy()->bytes_copied_during_gc()); |
| |
| 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(); |
| |
| if (VerifyRememberedSets) { |
| log_info(gc, verify)("[Verifying RemSets after GC]"); |
| VerifyRegionRemSetClosure v_cl; |
| heap_region_iterate(&v_cl); |
| } |
| |
| _verifier->verify_after_gc(); |
| _verifier->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. |
| } |
| |
| #ifdef TRACESPINNING |
| ParallelTaskTerminator::print_termination_counts(); |
| #endif |
| |
| gc_epilogue(false); |
| } |
| |
| // Print the remainder of the GC log output. |
| if (evacuation_failed()) { |
| log_info(gc)("To-space exhausted"); |
| } |
| |
| g1_policy()->print_phases(); |
| heap_transition.print(); |
| |
| // 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(); |
| _verifier->verify_region_sets_optional(); |
| |
| TASKQUEUE_STATS_ONLY(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::restore_preserved_marks() { |
| G1RestorePreservedMarksTask rpm_task(_preserved_objs); |
| workers()->run_task(&rpm_task); |
| } |
| |
| void G1CollectedHeap::remove_self_forwarding_pointers() { |
| G1ParRemoveSelfForwardPtrsTask rsfp_task; |
| workers()->run_task(&rsfp_task); |
| } |
| |
| void G1CollectedHeap::restore_after_evac_failure() { |
| double remove_self_forwards_start = os::elapsedTime(); |
| |
| remove_self_forwarding_pointers(); |
| restore_preserved_marks(); |
| |
| g1_policy()->phase_times()->record_evac_fail_remove_self_forwards((os::elapsedTime() - remove_self_forwards_start) * 1000.0); |
| } |
| |
| void G1CollectedHeap::preserve_mark_during_evac_failure(uint worker_id, oop obj, markOop m) { |
| if (!_evacuation_failed) { |
| _evacuation_failed = true; |
| } |
| |
| _evacuation_failed_info_array[worker_id].register_copy_failure(obj->size()); |
| |
| // 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)) { |
| OopAndMarkOop elem(obj, m); |
| _preserved_objs[worker_id].push(elem); |
| } |
| } |
| |
| bool G1ParEvacuateFollowersClosure::offer_termination() { |
| G1ParScanThreadState* const pss = par_scan_state(); |
| start_term_time(); |
| const bool res = terminator()->offer_termination(); |
| 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 G1ParTask : public AbstractGangTask { |
| protected: |
| G1CollectedHeap* _g1h; |
| G1ParScanThreadStateSet* _pss; |
| RefToScanQueueSet* _queues; |
| G1RootProcessor* _root_processor; |
| ParallelTaskTerminator _terminator; |
| uint _n_workers; |
| |
| public: |
| G1ParTask(G1CollectedHeap* g1h, G1ParScanThreadStateSet* per_thread_states, RefToScanQueueSet *task_queues, G1RootProcessor* root_processor, uint n_workers) |
| : AbstractGangTask("G1 collection"), |
| _g1h(g1h), |
| _pss(per_thread_states), |
| _queues(task_queues), |
| _root_processor(root_processor), |
| _terminator(n_workers, _queues), |
| _n_workers(n_workers) |
| {} |
| |
| void work(uint worker_id) { |
| if (worker_id >= _n_workers) return; // no work needed this round |
| |
| double start_sec = os::elapsedTime(); |
| _g1h->g1_policy()->phase_times()->record_time_secs(G1GCPhaseTimes::GCWorkerStart, worker_id, start_sec); |
| |
| { |
| ResourceMark rm; |
| HandleMark hm; |
| |
| ReferenceProcessor* rp = _g1h->ref_processor_stw(); |
| |
| G1ParScanThreadState* pss = _pss->state_for_worker(worker_id); |
| pss->set_ref_processor(rp); |
| |
| double start_strong_roots_sec = os::elapsedTime(); |
| |
| _root_processor->evacuate_roots(pss->closures(), worker_id); |
| |
| G1ParPushHeapRSClosure push_heap_rs_cl(_g1h, pss); |
| |
| // We pass a weak code blobs closure to the remembered set scanning because we want to avoid |
| // treating the nmethods visited to act as roots for concurrent marking. |
| // We only want to make sure that the oops in the nmethods are adjusted with regard to the |
| // objects copied by the current evacuation. |
| size_t cards_scanned = _g1h->g1_rem_set()->oops_into_collection_set_do(&push_heap_rs_cl, |
| pss->closures()->weak_codeblobs(), |
| worker_id); |
| |
| _pss->add_cards_scanned(worker_id, cards_scanned); |
| |
| double strong_roots_sec = os::elapsedTime() - start_strong_roots_sec; |
| |
| double term_sec = 0.0; |
| size_t evac_term_attempts = 0; |
| { |
| double start = os::elapsedTime(); |
| G1ParEvacuateFollowersClosure evac(_g1h, pss, _queues, &_terminator); |
| evac.do_void(); |
| |
| evac_term_attempts = evac.term_attempts(); |
| term_sec = evac.term_time(); |
| double elapsed_sec = os::elapsedTime() - start; |
| _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, evac_term_attempts); |
| } |
| |
| assert(pss->queue_is_empty(), "should be empty"); |
| |
| if (log_is_enabled(Debug, gc, task, stats)) { |
| MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag); |
| size_t lab_waste; |
| size_t lab_undo_waste; |
| pss->waste(lab_waste, lab_undo_waste); |
| _g1h->print_termination_stats(worker_id, |
| (os::elapsedTime() - start_sec) * 1000.0, /* elapsed time */ |
| strong_roots_sec * 1000.0, /* strong roots time */ |
| term_sec * 1000.0, /* evac term time */ |
| evac_term_attempts, /* evac term attempts */ |
| lab_waste, /* alloc buffer waste */ |
| lab_undo_waste /* undo waste */ |
| ); |
| } |
| |
| // 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()); |
| } |
| }; |
| |
| void G1CollectedHeap::print_termination_stats_hdr() { |
| log_debug(gc, task, stats)("GC Termination Stats"); |
| log_debug(gc, task, stats)(" elapsed --strong roots-- -------termination------- ------waste (KiB)------"); |
| log_debug(gc, task, stats)("thr ms ms %% ms %% attempts total alloc undo"); |
| log_debug(gc, task, stats)("--- --------- --------- ------ --------- ------ -------- ------- ------- -------"); |
| } |
| |
| void G1CollectedHeap::print_termination_stats(uint worker_id, |
| double elapsed_ms, |
| double strong_roots_ms, |
| double term_ms, |
| size_t term_attempts, |
| size_t alloc_buffer_waste, |
| size_t undo_waste) const { |
| log_debug(gc, task, stats) |
| ("%3d %9.2f %9.2f %6.2f " |
| "%9.2f %6.2f " SIZE_FORMAT_W(8) " " |
| SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7), |
| worker_id, elapsed_ms, strong_roots_ms, strong_roots_ms * 100 / elapsed_ms, |
| term_ms, term_ms * 100 / elapsed_ms, term_attempts, |
| (alloc_buffer_waste + undo_waste) * HeapWordSize / K, |
| alloc_buffer_waste * HeapWordSize / K, |
| undo_waste * HeapWordSize / K); |
| } |
| |
| 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, |
| "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, |
| "claim value %d after unlink less than initial symbol table size %d", |
| SymbolTable::parallel_claimed_index(), _initial_symbol_table_size); |
| |
| log_debug(gc, stringdedup)("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->is_instance_klass()); |
| |
| // this can be null so don't call InstanceKlass::cast |
| return static_cast<InstanceKlass*>(klass); |
| } |
| |
| public: |
| |
| void clean_klass(InstanceKlass* ik) { |
| ik->clean_weak_instanceklass_links(_is_alive); |
| } |
| |
| 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); |
| workers()->run_task(&g1_unlink_task); |
| } |
| |
| void G1CollectedHeap::unlink_string_and_symbol_table(BoolObjectClosure* is_alive, |
| bool process_strings, bool process_symbols) { |
| { |
| G1StringSymbolTableUnlinkTask g1_unlink_task(is_alive, process_strings, process_symbols); |
| workers()->run_task(&g1_unlink_task); |
| } |
| |
| if (G1StringDedup::is_enabled()) { |
| G1StringDedup::unlink(is_alive); |
| } |
| } |
| |
| class G1RedirtyLoggedCardsTask : public AbstractGangTask { |
| private: |
| DirtyCardQueueSet* _queue; |
| G1CollectedHeap* _g1h; |
| public: |
| G1RedirtyLoggedCardsTask(DirtyCardQueueSet* queue, G1CollectedHeap* g1h) : AbstractGangTask("Redirty Cards"), |
| _queue(queue), _g1h(g1h) { } |
| |
| virtual void work(uint worker_id) { |
| G1GCPhaseTimes* phase_times = _g1h->g1_policy()->phase_times(); |
| G1GCParPhaseTimesTracker x(phase_times, G1GCPhaseTimes::RedirtyCards, worker_id); |
| |
| RedirtyLoggedCardTableEntryClosure cl(_g1h); |
| _queue->par_apply_closure_to_all_completed_buffers(&cl); |
| |
| phase_times->record_thread_work_item(G1GCPhaseTimes::RedirtyCards, worker_id, cl.num_dirtied()); |
| } |
| }; |
| |
| void G1CollectedHeap::redirty_logged_cards() { |
| double redirty_logged_cards_start = os::elapsedTime(); |
| |
| G1RedirtyLoggedCardsTask redirty_task(&dirty_card_queue_set(), this); |
| dirty_card_queue_set().reset_for_par_iteration(); |
| workers()->run_task(&redirty_task); |
| |
| 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->is_in_cset(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(), |
| "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), |
| "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; |
| G1ParScanThreadStateSet* _pss; |
| RefToScanQueueSet* _queues; |
| WorkGang* _workers; |
| uint _active_workers; |
| |
| public: |
| G1STWRefProcTaskExecutor(G1CollectedHeap* g1h, |
| G1ParScanThreadStateSet* per_thread_states, |
| WorkGang* workers, |
| RefToScanQueueSet *task_queues, |
| uint n_workers) : |
| _g1h(g1h), |
| _pss(per_thread_states), |
| _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; |
| G1ParScanThreadStateSet* _pss; |
| RefToScanQueueSet* _task_queues; |
| ParallelTaskTerminator* _terminator; |
| |
| public: |
| G1STWRefProcTaskProxy(ProcessTask& proc_task, |
| G1CollectedHeap* g1h, |
| G1ParScanThreadStateSet* per_thread_states, |
| RefToScanQueueSet *task_queues, |
| ParallelTaskTerminator* terminator) : |
| AbstractGangTask("Process reference objects in parallel"), |
| _proc_task(proc_task), |
| _g1h(g1h), |
| _pss(per_thread_states), |
| _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 = _pss->state_for_worker(worker_id); |
| pss->set_ref_processor(NULL); |
| |
| // Keep alive closure. |
| G1CopyingKeepAliveClosure keep_alive(_g1h, pss->closures()->raw_strong_oops(), 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, _pss, _queues, &terminator); |
| |
| _workers->run_task(&proc_task_proxy); |
| } |
| |
| // 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); |
| |
| _workers->run_task(&enq_task_proxy); |
| } |
| |
| // 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; |
| G1ParScanThreadStateSet* _pss; |
| RefToScanQueueSet* _queues; |
| ParallelTaskTerminator _terminator; |
| uint _n_workers; |
| |
| public: |
| G1ParPreserveCMReferentsTask(G1CollectedHeap* g1h, G1ParScanThreadStateSet* per_thread_states, int workers, RefToScanQueueSet *task_queues) : |
| AbstractGangTask("ParPreserveCMReferents"), |
| _g1h(g1h), |
| _pss(per_thread_states), |
| _queues(task_queues), |
| _terminator(workers, _queues), |
| _n_workers(workers) |
| { } |
| |
| void work(uint worker_id) { |
| G1GCParPhaseTimesTracker x(_g1h->g1_policy()->phase_times(), G1GCPhaseTimes::PreserveCMReferents, worker_id); |
| |
| ResourceMark rm; |
| HandleMark hm; |
| |
| G1ParScanThreadState* pss = _pss->state_for_worker(worker_id); |
| pss->set_ref_processor(NULL); |
| assert(pss->queue_is_empty(), "both queue and overflow should be empty"); |
| |
| // Is alive closure |
| G1AlwaysAliveClosure always_alive(_g1h); |
| |
| // Copying keep alive closure. Applied to referent objects that need |
| // to be copied. |
| G1CopyingKeepAliveClosure keep_alive(_g1h, pss->closures()->raw_strong_oops(), 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"); |
| } |
| }; |
| |
| void G1CollectedHeap::process_weak_jni_handles() { |
| double ref_proc_start = os::elapsedTime(); |
| |
| G1STWIsAliveClosure is_alive(this); |
| G1KeepAliveClosure keep_alive(this); |
| JNIHandles::weak_oops_do(&is_alive, &keep_alive); |
| |
| double ref_proc_time = os::elapsedTime() - ref_proc_start; |
| g1_policy()->phase_times()->record_ref_proc_time(ref_proc_time * 1000.0); |
| } |
| |
| void G1CollectedHeap::preserve_cm_referents(G1ParScanThreadStateSet* per_thread_states) { |
| double preserve_cm_referents_start = os::elapsedTime(); |
| // 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. |
| |
| uint no_of_gc_workers = workers()->active_workers(); |
| |
| G1ParPreserveCMReferentsTask keep_cm_referents(this, |
| per_thread_states, |
| no_of_gc_workers, |
| _task_queues); |
| workers()->run_task(&keep_cm_referents); |
| |
| g1_policy()->phase_times()->record_preserve_cm_referents_time_ms((os::elapsedTime() - preserve_cm_referents_start) * 1000.0); |
| } |
| |
| // Weak Reference processing during an evacuation pause (part 1). |
| void G1CollectedHeap::process_discovered_references(G1ParScanThreadStateSet* per_thread_states) { |
| double ref_proc_start = os::elapsedTime(); |
| |
| ReferenceProcessor* rp = _ref_processor_stw; |
| assert(rp->discovery_enabled(), "should have been enabled"); |
| |
| // 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 = per_thread_states->state_for_worker(0); |
| pss->set_ref_processor(NULL); |
| assert(pss->queue_is_empty(), "pre-condition"); |
| |
| // Keep alive closure. |
| G1CopyingKeepAliveClosure keep_alive(this, pss->closures()->raw_strong_oops(), 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); |
| } else { |
| uint no_of_gc_workers = workers()->active_workers(); |
| |
| // 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, per_thread_states, 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->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(G1ParScanThreadStateSet* per_thread_states) { |
| 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 |
| |
| uint n_workers = workers()->active_workers(); |
| |
| assert(rp->num_q() == n_workers, "sanity"); |
| assert(n_workers <= rp->max_num_q(), "sanity"); |
| |
| G1STWRefProcTaskExecutor par_task_executor(this, per_thread_states, workers(), _task_queues, n_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::merge_per_thread_state_info(G1ParScanThreadStateSet* per_thread_states) { |
| double merge_pss_time_start = os::elapsedTime(); |
| per_thread_states->flush(); |
| g1_policy()->phase_times()->record_merge_pss_time_ms((os::elapsedTime() - merge_pss_time_start) * 1000.0); |
| } |
| |
| void G1CollectedHeap::pre_evacuate_collection_set() { |
| _expand_heap_after_alloc_failure = true; |
| _evacuation_failed = false; |
| |
| // 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); |
| |
| g1_rem_set()->prepare_for_oops_into_collection_set_do(); |
| } |
| |
| void G1CollectedHeap::evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* per_thread_states) { |
| // Should G1EvacuationFailureALot be in effect for this GC? |
| NOT_PRODUCT(set_evacuation_failure_alot_for_current_gc();) |
| |
| assert(dirty_card_queue_set().completed_buffers_num() == 0, "Should be empty"); |
| double start_par_time_sec = os::elapsedTime(); |
| double end_par_time_sec; |
| |
| { |
| const uint n_workers = workers()->active_workers(); |
| G1RootProcessor root_processor(this, n_workers); |
| G1ParTask g1_par_task(this, per_thread_states, _task_queues, &root_processor, n_workers); |
| // InitialMark needs claim bits to keep track of the marked-through CLDs. |
| if (collector_state()->during_initial_mark_pause()) { |
| ClassLoaderDataGraph::clear_claimed_marks(); |
| } |
| |
| print_termination_stats_hdr(); |
| |
| 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); |
| } |
| |
| void G1CollectedHeap::post_evacuate_collection_set(EvacuationInfo& evacuation_info, G1ParScanThreadStateSet* per_thread_states) { |
| // 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. |
| if (g1_policy()->should_process_references()) { |
| preserve_cm_referents(per_thread_states); |
| process_discovered_references(per_thread_states); |
| } else { |
| ref_processor_stw()->verify_no_references_recorded(); |
| process_weak_jni_handles(); |
| } |
| |
| 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, g1_policy()->phase_times()); |
| |
| double fixup_time_ms = (os::elapsedTime() - fixup_start) * 1000.0; |
| g1_policy()->phase_times()->record_string_dedup_fixup_time(fixup_time_ms); |
| } |
| |
| g1_rem_set()->cleanup_after_oops_into_collection_set_do(); |
| |
| if (evacuation_failed()) { |
| restore_after_evac_failure(); |
| |
| // 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. |
| if (g1_policy()->should_process_references()) { |
| enqueue_discovered_references(per_thread_states); |
| } else { |
| g1_policy()->phase_times()->record_ref_enq_time(0); |
| } |
| |
| _allocator->release_gc_alloc_regions(evacuation_info); |
| |
| merge_per_thread_state_info(per_thread_states); |
| |
| // 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. |
| G1HotCardCache* hot_card_cache = _cg1r->hot_card_cache(); |
| hot_card_cache->reset_hot_cache(); |
| hot_card_cache->set_use_cache(true); |
| |
| purge_code_root_memory(); |
| |
| redirty_logged_cards(); |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::update_pointers(); |
| #endif |
| } |
| |
| void G1CollectedHeap::record_obj_copy_mem_stats() { |
| g1_policy()->add_bytes_allocated_in_old_since_last_gc(_old_evac_stats.allocated() * HeapWordSize); |
| |
| _gc_tracer_stw->report_evacuation_statistics(create_g1_evac_summary(&_survivor_evac_stats), |
| create_g1_evac_summary(&_old_evac_stats)); |
| } |
| |
| 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_humongous(), "this is only for humongous regions"); |
| assert(free_list != NULL, "pre-condition"); |
| hr->clear_humongous(); |
| free_region(hr, free_list, par); |
| } |
| |
| void G1CollectedHeap::remove_from_old_sets(const uint old_regions_removed, |
| const uint humongous_regions_removed) { |
| if (old_regions_removed > 0 || humongous_regions_removed > 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) { |
| 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())); |
| } |
| } |
| }; |
| |
| class G1ParScrubRemSetTask: public AbstractGangTask { |
| protected: |
| G1RemSet* _g1rs; |
| BitMap* _region_bm; |
| BitMap* _card_bm; |
| HeapRegionClaimer _hrclaimer; |
| |
| public: |
| G1ParScrubRemSetTask(G1RemSet* g1_rs, BitMap* region_bm, BitMap* card_bm, uint num_workers) : |
| AbstractGangTask("G1 ScrubRS"), |
| _g1rs(g1_rs), |
| _region_bm(region_bm), |
| _card_bm(card_bm), |
| _hrclaimer(num_workers) { |
| } |
| |
| void work(uint worker_id) { |
| _g1rs->scrub(_region_bm, _card_bm, worker_id, &_hrclaimer); |
| } |
| }; |
| |
| void G1CollectedHeap::scrub_rem_set(BitMap* region_bm, BitMap* card_bm) { |
| uint num_workers = workers()->active_workers(); |
| G1ParScrubRemSetTask g1_par_scrub_rs_task(g1_rem_set(), region_bm, card_bm, num_workers); |
| workers()->run_task(&g1_par_scrub_rs_task); |
| } |
| |
| 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); |
| |
| workers()->run_task(&cleanup_task); |
| #ifndef PRODUCT |
| _verifier->verify_card_table_cleanup(); |
| #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, const size_t* surviving_young_words) { |
| 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); |
| // When moving a young gen region to old gen, we "allocate" that whole region |
| // there. This is in addition to any already evacuated objects. Notify the |
| // policy about that. |
| // Old gen regions do not cause an additional allocation: both the objects |
| // still in the region and the ones already moved are accounted for elsewhere. |
| if (cur->is_young()) { |
| policy->add_bytes_allocated_in_old_since_last_gc(HeapRegion::GrainBytes); |
| } |
| // The region is now considered to be old. |
| cur->set_old(); |
| // Do some allocation statistics accounting. Regions that failed evacuation |
| // are always made old, so there is no need to update anything in the young |
| // gen statistics, but we need to update old gen statistics. |
| size_t used_words = cur->marked_bytes() / HeapWordSize; |
| _old_evac_stats.add_failure_used_and_waste(used_words, HeapRegion::GrainWords - used_words); |
| _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; |
| uint _humongous_regions_removed; |
| size_t _freed_bytes; |
| public: |
| |
| G1FreeHumongousRegionClosure(FreeRegionList* free_region_list) : |
| _free_region_list(free_region_list), _humongous_regions_removed(0), _freed_bytes(0) { |
| } |
| |
| virtual bool doHeapRegion(HeapRegion* r) { |
| if (!r->is_starts_humongous()) { |
| return false; |
| } |
| |
| G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
| |
| oop obj = (oop)r->bottom(); |
| G1CMBitMap* 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()) { |
| log_debug(gc, humongous)("Live humongous region %u object size " SIZE_FORMAT " start " PTR_FORMAT " 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->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(), |
| "Only eagerly reclaiming type arrays is supported, but the object " |
| PTR_FORMAT " is not.", p2i(r->bottom())); |
| |
| log_debug(gc, humongous)("Dead humongous region %u object size " SIZE_FORMAT " start " PTR_FORMAT " 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->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()); |
| } |
| do { |
| HeapRegion* next = g1h->next_region_in_humongous(r); |
| _freed_bytes += r->used(); |
| r->set_containing_set(NULL); |
| _humongous_regions_removed++; |
| g1h->free_humongous_region(r, _free_region_list, false); |
| r = next; |
| } while (r != NULL); |
| |
| return false; |
| } |
| |
| uint humongous_free_count() { |
| return _humongous_regions_removed; |
| } |
| |
| size_t bytes_freed() const { |
| return _freed_bytes; |
| } |
| }; |
| |
| void G1CollectedHeap::eagerly_reclaim_humongous_regions() { |
| assert_at_safepoint(true); |
| |
| if (!G1EagerReclaimHumongousObjects || |
| (!_has_humongous_reclaim_candidates && !log_is_enabled(Debug, gc, humongous))) { |
| 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); |
| |
| remove_from_old_sets(0, 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_free_count()); |
| } |
| |
| // 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() { |
| log_develop_trace(gc, freelist)("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(); |
| } |
| |
| log_develop_trace(gc, freelist)("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; |
| } |
| |
| log_develop_trace(gc, freelist)("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); |
| } |
| } |
| |
| log_develop_trace(gc, freelist)("G1ConcRegionFreeing [other] : done waiting for free regions"); |
| } |
| |
| bool G1CollectedHeap::is_old_gc_alloc_region(HeapRegion* hr) { |
| return _allocator->is_retained_old_region(hr); |
| } |
| |
| 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()) { |
| log_error(gc, verify)("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 ret = _young_list->check_list_empty(); |
| |
| 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(); |
| } |
| |
| void G1CollectedHeap::increase_used(size_t bytes) { |
| _summary_bytes_used += bytes; |
| } |
| |
| void G1CollectedHeap::decrease_used(size_t bytes) { |
| assert(_summary_bytes_used >= bytes, |
| "invariant: _summary_bytes_used: " SIZE_FORMAT " should be >= bytes: " SIZE_FORMAT, |
| _summary_bytes_used, bytes); |
| _summary_bytes_used -= bytes; |
| } |
| |
| void G1CollectedHeap::set_used(size_t bytes) { |
| _summary_bytes_used = bytes; |
| } |
| |
| 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_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. Archive regions (which are |
| // old) will not have been touched. |
| assert(r->is_free() || r->is_old(), "invariant"); |
| // We now consider them old, so register as such. Leave |
| // archive regions set that way, however, while still adding |
| // them to the old set. |
| if (!r->is_archive()) { |
| 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) { |
| set_used(cl.total_used()); |
| if (_archive_allocator != NULL) { |
| _archive_allocator->clear_used(); |
| } |
| } |
| assert(used_unlocked() == recalculate_used(), |
| "inconsistent used_unlocked(), " |
| "value: " SIZE_FORMAT " recalculated: " SIZE_FORMAT, |
| 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, young_list_full); |
| _verifier->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); |
| 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(); |
| } |
| |
| // 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(); |
| _verifier->check_bitmaps("Survivor Region Allocation", new_alloc_region); |
| } else { |
| new_alloc_region->set_old(); |
| _verifier->check_bitmaps("Old Region Allocation", new_alloc_region); |
| } |
| _hr_printer.alloc(new_alloc_region); |
| bool during_im = collector_state()->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 = collector_state()->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); |
| } |
| |
| HeapRegion* G1CollectedHeap::alloc_highest_free_region() { |
| bool expanded = false; |
| uint index = _hrm.find_highest_free(&expanded); |
| |
| if (index != G1_NO_HRM_INDEX) { |
| if (expanded) { |
| log_debug(gc, ergo, heap)("Attempt heap expansion (requested address range outside heap bounds). region size: " SIZE_FORMAT "B", |
| HeapRegion::GrainWords * HeapWordSize); |
| } |
| _hrm.allocate_free_regions_starting_at(index, 1); |
| return region_at(index); |
| } |
| return NULL; |
| } |
| |
| // 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(), |
| "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(), |
| "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); |
| } |