| /* |
| * Copyright (c) 2000, 2023, 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/classLoaderDataGraph.hpp" |
| #include "classfile/stringTable.hpp" |
| #include "classfile/symbolTable.hpp" |
| #include "classfile/vmSymbols.hpp" |
| #include "code/codeCache.hpp" |
| #include "code/icBuffer.hpp" |
| #include "compiler/oopMap.hpp" |
| #include "gc/serial/cardTableRS.hpp" |
| #include "gc/serial/defNewGeneration.hpp" |
| #include "gc/serial/genMarkSweep.hpp" |
| #include "gc/serial/markSweep.hpp" |
| #include "gc/shared/adaptiveSizePolicy.hpp" |
| #include "gc/shared/cardTableBarrierSet.hpp" |
| #include "gc/shared/classUnloadingContext.hpp" |
| #include "gc/shared/collectedHeap.inline.hpp" |
| #include "gc/shared/collectorCounters.hpp" |
| #include "gc/shared/continuationGCSupport.inline.hpp" |
| #include "gc/shared/gcId.hpp" |
| #include "gc/shared/gcInitLogger.hpp" |
| #include "gc/shared/gcLocker.hpp" |
| #include "gc/shared/gcPolicyCounters.hpp" |
| #include "gc/shared/gcTrace.hpp" |
| #include "gc/shared/gcTraceTime.inline.hpp" |
| #include "gc/shared/gcVMOperations.hpp" |
| #include "gc/shared/genArguments.hpp" |
| #include "gc/shared/genCollectedHeap.hpp" |
| #include "gc/shared/generationSpec.hpp" |
| #include "gc/shared/locationPrinter.inline.hpp" |
| #include "gc/shared/oopStorage.inline.hpp" |
| #include "gc/shared/oopStorageParState.inline.hpp" |
| #include "gc/shared/oopStorageSet.inline.hpp" |
| #include "gc/shared/scavengableNMethods.hpp" |
| #include "gc/shared/space.hpp" |
| #include "gc/shared/strongRootsScope.hpp" |
| #include "gc/shared/weakProcessor.hpp" |
| #include "gc/shared/workerThread.hpp" |
| #include "memory/iterator.hpp" |
| #include "memory/metaspaceCounters.hpp" |
| #include "memory/metaspaceUtils.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "memory/universe.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/handles.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/java.hpp" |
| #include "runtime/threads.hpp" |
| #include "runtime/vmThread.hpp" |
| #include "services/memoryService.hpp" |
| #include "utilities/autoRestore.hpp" |
| #include "utilities/debug.hpp" |
| #include "utilities/formatBuffer.hpp" |
| #include "utilities/macros.hpp" |
| #include "utilities/stack.inline.hpp" |
| #include "utilities/vmError.hpp" |
| #if INCLUDE_JVMCI |
| #include "jvmci/jvmci.hpp" |
| #endif |
| |
| GenCollectedHeap::GenCollectedHeap(Generation::Name young, |
| Generation::Name old, |
| const char* policy_counters_name) : |
| CollectedHeap(), |
| _young_gen(nullptr), |
| _old_gen(nullptr), |
| _young_gen_spec(new GenerationSpec(young, |
| NewSize, |
| MaxNewSize, |
| GenAlignment)), |
| _old_gen_spec(new GenerationSpec(old, |
| OldSize, |
| MaxOldSize, |
| GenAlignment)), |
| _rem_set(nullptr), |
| _soft_ref_gen_policy(), |
| _size_policy(nullptr), |
| _gc_policy_counters(new GCPolicyCounters(policy_counters_name, 2, 2)), |
| _incremental_collection_failed(false), |
| _full_collections_completed(0), |
| _young_manager(nullptr), |
| _old_manager(nullptr) { |
| } |
| |
| jint GenCollectedHeap::initialize() { |
| // Allocate space for the heap. |
| |
| ReservedHeapSpace heap_rs = allocate(HeapAlignment); |
| |
| if (!heap_rs.is_reserved()) { |
| vm_shutdown_during_initialization( |
| "Could not reserve enough space for object heap"); |
| return JNI_ENOMEM; |
| } |
| |
| initialize_reserved_region(heap_rs); |
| |
| ReservedSpace young_rs = heap_rs.first_part(_young_gen_spec->max_size()); |
| ReservedSpace old_rs = heap_rs.last_part(_young_gen_spec->max_size()); |
| |
| _rem_set = create_rem_set(heap_rs.region()); |
| _rem_set->initialize(young_rs.base(), old_rs.base()); |
| |
| CardTableBarrierSet *bs = new CardTableBarrierSet(_rem_set); |
| bs->initialize(); |
| BarrierSet::set_barrier_set(bs); |
| |
| _young_gen = _young_gen_spec->init(young_rs, rem_set()); |
| _old_gen = _old_gen_spec->init(old_rs, rem_set()); |
| |
| GCInitLogger::print(); |
| |
| return JNI_OK; |
| } |
| |
| CardTableRS* GenCollectedHeap::create_rem_set(const MemRegion& reserved_region) { |
| return new CardTableRS(reserved_region); |
| } |
| |
| void GenCollectedHeap::initialize_size_policy(size_t init_eden_size, |
| size_t init_promo_size, |
| size_t init_survivor_size) { |
| const double max_gc_pause_sec = ((double) MaxGCPauseMillis) / 1000.0; |
| _size_policy = new AdaptiveSizePolicy(init_eden_size, |
| init_promo_size, |
| init_survivor_size, |
| max_gc_pause_sec, |
| GCTimeRatio); |
| } |
| |
| ReservedHeapSpace GenCollectedHeap::allocate(size_t alignment) { |
| // Now figure out the total size. |
| const size_t pageSize = UseLargePages ? os::large_page_size() : os::vm_page_size(); |
| assert(alignment % pageSize == 0, "Must be"); |
| |
| // Check for overflow. |
| size_t total_reserved = _young_gen_spec->max_size() + _old_gen_spec->max_size(); |
| if (total_reserved < _young_gen_spec->max_size()) { |
| vm_exit_during_initialization("The size of the object heap + VM data exceeds " |
| "the maximum representable size"); |
| } |
| assert(total_reserved % alignment == 0, |
| "Gen size; total_reserved=" SIZE_FORMAT ", alignment=" |
| SIZE_FORMAT, total_reserved, alignment); |
| |
| ReservedHeapSpace heap_rs = Universe::reserve_heap(total_reserved, alignment); |
| size_t used_page_size = heap_rs.page_size(); |
| |
| os::trace_page_sizes("Heap", |
| MinHeapSize, |
| total_reserved, |
| used_page_size, |
| heap_rs.base(), |
| heap_rs.size()); |
| |
| return heap_rs; |
| } |
| |
| class GenIsScavengable : public BoolObjectClosure { |
| public: |
| bool do_object_b(oop obj) { |
| return GenCollectedHeap::heap()->is_in_young(obj); |
| } |
| }; |
| |
| static GenIsScavengable _is_scavengable; |
| |
| void GenCollectedHeap::post_initialize() { |
| CollectedHeap::post_initialize(); |
| |
| DefNewGeneration* def_new_gen = (DefNewGeneration*)_young_gen; |
| |
| def_new_gen->ref_processor_init(); |
| |
| initialize_size_policy(def_new_gen->eden()->capacity(), |
| _old_gen->capacity(), |
| def_new_gen->from()->capacity()); |
| |
| MarkSweep::initialize(); |
| |
| ScavengableNMethods::initialize(&_is_scavengable); |
| } |
| |
| PreGenGCValues GenCollectedHeap::get_pre_gc_values() const { |
| const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); |
| |
| return PreGenGCValues(def_new_gen->used(), |
| def_new_gen->capacity(), |
| def_new_gen->eden()->used(), |
| def_new_gen->eden()->capacity(), |
| def_new_gen->from()->used(), |
| def_new_gen->from()->capacity(), |
| old_gen()->used(), |
| old_gen()->capacity()); |
| } |
| |
| GenerationSpec* GenCollectedHeap::young_gen_spec() const { |
| return _young_gen_spec; |
| } |
| |
| GenerationSpec* GenCollectedHeap::old_gen_spec() const { |
| return _old_gen_spec; |
| } |
| |
| size_t GenCollectedHeap::capacity() const { |
| return _young_gen->capacity() + _old_gen->capacity(); |
| } |
| |
| size_t GenCollectedHeap::used() const { |
| return _young_gen->used() + _old_gen->used(); |
| } |
| |
| void GenCollectedHeap::save_used_regions() { |
| _old_gen->save_used_region(); |
| _young_gen->save_used_region(); |
| } |
| |
| size_t GenCollectedHeap::max_capacity() const { |
| return _young_gen->max_capacity() + _old_gen->max_capacity(); |
| } |
| |
| // Update the _full_collections_completed counter |
| // at the end of a stop-world full GC. |
| unsigned int GenCollectedHeap::update_full_collections_completed() { |
| assert(_full_collections_completed <= _total_full_collections, |
| "Can't complete more collections than were started"); |
| _full_collections_completed = _total_full_collections; |
| return _full_collections_completed; |
| } |
| |
| // Return true if any of the following is true: |
| // . the allocation won't fit into the current young gen heap |
| // . gc locker is occupied (jni critical section) |
| // . heap memory is tight -- the most recent previous collection |
| // was a full collection because a partial collection (would |
| // have) failed and is likely to fail again |
| bool GenCollectedHeap::should_try_older_generation_allocation(size_t word_size) const { |
| size_t young_capacity = _young_gen->capacity_before_gc(); |
| return (word_size > heap_word_size(young_capacity)) |
| || GCLocker::is_active_and_needs_gc() |
| || incremental_collection_failed(); |
| } |
| |
| HeapWord* GenCollectedHeap::expand_heap_and_allocate(size_t size, bool is_tlab) { |
| HeapWord* result = nullptr; |
| if (_old_gen->should_allocate(size, is_tlab)) { |
| result = _old_gen->expand_and_allocate(size, is_tlab); |
| } |
| if (result == nullptr) { |
| if (_young_gen->should_allocate(size, is_tlab)) { |
| result = _young_gen->expand_and_allocate(size, is_tlab); |
| } |
| } |
| assert(result == nullptr || is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| HeapWord* GenCollectedHeap::mem_allocate_work(size_t size, |
| bool is_tlab) { |
| |
| HeapWord* result = nullptr; |
| |
| // Loop until the allocation is satisfied, or unsatisfied after GC. |
| for (uint try_count = 1, gclocker_stalled_count = 0; /* return or throw */; try_count += 1) { |
| |
| // First allocation attempt is lock-free. |
| Generation *young = _young_gen; |
| if (young->should_allocate(size, is_tlab)) { |
| result = young->par_allocate(size, is_tlab); |
| if (result != nullptr) { |
| assert(is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| } |
| uint gc_count_before; // Read inside the Heap_lock locked region. |
| { |
| MutexLocker ml(Heap_lock); |
| log_trace(gc, alloc)("GenCollectedHeap::mem_allocate_work: attempting locked slow path allocation"); |
| // Note that only large objects get a shot at being |
| // allocated in later generations. |
| bool first_only = !should_try_older_generation_allocation(size); |
| |
| result = attempt_allocation(size, is_tlab, first_only); |
| if (result != nullptr) { |
| assert(is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| if (GCLocker::is_active_and_needs_gc()) { |
| if (is_tlab) { |
| return nullptr; // Caller will retry allocating individual object. |
| } |
| if (!is_maximal_no_gc()) { |
| // Try and expand heap to satisfy request. |
| result = expand_heap_and_allocate(size, is_tlab); |
| // Result could be null if we are out of space. |
| if (result != nullptr) { |
| return result; |
| } |
| } |
| |
| if (gclocker_stalled_count > GCLockerRetryAllocationCount) { |
| return nullptr; // We didn't get to do a GC and we didn't get any memory. |
| } |
| |
| // If this thread is not in a jni critical section, we stall |
| // the requestor until the critical section has cleared and |
| // GC allowed. When the critical section clears, a GC is |
| // initiated by the last thread exiting the critical section; so |
| // we retry the allocation sequence from the beginning of the loop, |
| // rather than causing more, now probably unnecessary, GC attempts. |
| JavaThread* jthr = JavaThread::current(); |
| if (!jthr->in_critical()) { |
| MutexUnlocker mul(Heap_lock); |
| // Wait for JNI critical section to be exited |
| GCLocker::stall_until_clear(); |
| gclocker_stalled_count += 1; |
| continue; |
| } else { |
| if (CheckJNICalls) { |
| fatal("Possible deadlock due to allocating while" |
| " in jni critical section"); |
| } |
| return nullptr; |
| } |
| } |
| |
| // Read the gc count while the heap lock is held. |
| gc_count_before = total_collections(); |
| } |
| |
| VM_GenCollectForAllocation op(size, is_tlab, gc_count_before); |
| VMThread::execute(&op); |
| if (op.prologue_succeeded()) { |
| result = op.result(); |
| if (op.gc_locked()) { |
| assert(result == nullptr, "must be null if gc_locked() is true"); |
| continue; // Retry and/or stall as necessary. |
| } |
| |
| assert(result == nullptr || is_in_reserved(result), |
| "result not in heap"); |
| return result; |
| } |
| |
| // Give a warning if we seem to be looping forever. |
| if ((QueuedAllocationWarningCount > 0) && |
| (try_count % QueuedAllocationWarningCount == 0)) { |
| log_warning(gc, ergo)("GenCollectedHeap::mem_allocate_work retries %d times," |
| " size=" SIZE_FORMAT " %s", try_count, size, is_tlab ? "(TLAB)" : ""); |
| } |
| } |
| } |
| |
| HeapWord* GenCollectedHeap::attempt_allocation(size_t size, |
| bool is_tlab, |
| bool first_only) { |
| HeapWord* res = nullptr; |
| |
| if (_young_gen->should_allocate(size, is_tlab)) { |
| res = _young_gen->allocate(size, is_tlab); |
| if (res != nullptr || first_only) { |
| return res; |
| } |
| } |
| |
| if (_old_gen->should_allocate(size, is_tlab)) { |
| res = _old_gen->allocate(size, is_tlab); |
| } |
| |
| return res; |
| } |
| |
| HeapWord* GenCollectedHeap::mem_allocate(size_t size, |
| bool* gc_overhead_limit_was_exceeded) { |
| return mem_allocate_work(size, |
| false /* is_tlab */); |
| } |
| |
| bool GenCollectedHeap::must_clear_all_soft_refs() { |
| return _gc_cause == GCCause::_metadata_GC_clear_soft_refs || |
| _gc_cause == GCCause::_wb_full_gc; |
| } |
| |
| void GenCollectedHeap::collect_generation(Generation* gen, bool full, size_t size, |
| bool is_tlab, bool run_verification, bool clear_soft_refs) { |
| FormatBuffer<> title("Collect gen: %s", gen->short_name()); |
| GCTraceTime(Trace, gc, phases) t1(title); |
| TraceCollectorStats tcs(gen->counters()); |
| TraceMemoryManagerStats tmms(gen->gc_manager(), gc_cause(), heap()->is_young_gen(gen) ? "end of minor GC" : "end of major GC"); |
| |
| gen->stat_record()->invocations++; |
| gen->stat_record()->accumulated_time.start(); |
| |
| // Must be done anew before each collection because |
| // a previous collection will do mangling and will |
| // change top of some spaces. |
| record_gen_tops_before_GC(); |
| |
| log_trace(gc)("%s invoke=%d size=" SIZE_FORMAT, heap()->is_young_gen(gen) ? "Young" : "Old", gen->stat_record()->invocations, size * HeapWordSize); |
| |
| if (run_verification && VerifyBeforeGC) { |
| Universe::verify("Before GC"); |
| } |
| COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::clear()); |
| |
| // Do collection work |
| { |
| save_marks(); // save marks for all gens |
| |
| gen->collect(full, clear_soft_refs, size, is_tlab); |
| } |
| |
| COMPILER2_OR_JVMCI_PRESENT(DerivedPointerTable::update_pointers()); |
| |
| gen->stat_record()->accumulated_time.stop(); |
| |
| update_gc_stats(gen, full); |
| |
| if (run_verification && VerifyAfterGC) { |
| Universe::verify("After GC"); |
| } |
| } |
| |
| void GenCollectedHeap::do_collection(bool full, |
| bool clear_all_soft_refs, |
| size_t size, |
| bool is_tlab, |
| GenerationType max_generation) { |
| ResourceMark rm; |
| DEBUG_ONLY(Thread* my_thread = Thread::current();) |
| |
| assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
| assert(my_thread->is_VM_thread(), "only VM thread"); |
| assert(Heap_lock->is_locked(), |
| "the requesting thread should have the Heap_lock"); |
| guarantee(!is_gc_active(), "collection is not reentrant"); |
| |
| if (GCLocker::check_active_before_gc()) { |
| return; // GC is disabled (e.g. JNI GetXXXCritical operation) |
| } |
| |
| const bool do_clear_all_soft_refs = clear_all_soft_refs || |
| soft_ref_policy()->should_clear_all_soft_refs(); |
| |
| ClearedAllSoftRefs casr(do_clear_all_soft_refs, soft_ref_policy()); |
| |
| AutoModifyRestore<bool> temporarily(_is_gc_active, true); |
| |
| bool complete = full && (max_generation == OldGen); |
| bool old_collects_young = complete && !ScavengeBeforeFullGC; |
| bool do_young_collection = !old_collects_young && _young_gen->should_collect(full, size, is_tlab); |
| |
| const PreGenGCValues pre_gc_values = get_pre_gc_values(); |
| |
| bool run_verification = total_collections() >= VerifyGCStartAt; |
| bool prepared_for_verification = false; |
| bool do_full_collection = false; |
| |
| if (do_young_collection) { |
| GCIdMark gc_id_mark; |
| GCTraceCPUTime tcpu(((DefNewGeneration*)_young_gen)->gc_tracer()); |
| GCTraceTime(Info, gc) t("Pause Young", nullptr, gc_cause(), true); |
| |
| print_heap_before_gc(); |
| |
| if (run_verification && VerifyGCLevel <= 0 && VerifyBeforeGC) { |
| prepare_for_verify(); |
| prepared_for_verification = true; |
| } |
| |
| gc_prologue(complete); |
| increment_total_collections(complete); |
| |
| collect_generation(_young_gen, |
| full, |
| size, |
| is_tlab, |
| run_verification && VerifyGCLevel <= 0, |
| do_clear_all_soft_refs); |
| |
| if (size > 0 && (!is_tlab || _young_gen->supports_tlab_allocation()) && |
| size * HeapWordSize <= _young_gen->unsafe_max_alloc_nogc()) { |
| // Allocation request was met by young GC. |
| size = 0; |
| } |
| |
| // Ask if young collection is enough. If so, do the final steps for young collection, |
| // and fallthrough to the end. |
| do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); |
| if (!do_full_collection) { |
| // Adjust generation sizes. |
| _young_gen->compute_new_size(); |
| |
| print_heap_change(pre_gc_values); |
| |
| // Track memory usage and detect low memory after GC finishes |
| MemoryService::track_memory_usage(); |
| |
| gc_epilogue(complete); |
| } |
| |
| print_heap_after_gc(); |
| |
| } else { |
| // No young collection, ask if we need to perform Full collection. |
| do_full_collection = should_do_full_collection(size, full, is_tlab, max_generation); |
| } |
| |
| if (do_full_collection) { |
| GCIdMark gc_id_mark; |
| GCTraceCPUTime tcpu(GenMarkSweep::gc_tracer()); |
| GCTraceTime(Info, gc) t("Pause Full", nullptr, gc_cause(), true); |
| |
| print_heap_before_gc(); |
| |
| if (!prepared_for_verification && run_verification && |
| VerifyGCLevel <= 1 && VerifyBeforeGC) { |
| prepare_for_verify(); |
| } |
| |
| if (!do_young_collection) { |
| gc_prologue(complete); |
| increment_total_collections(complete); |
| } |
| |
| // Accounting quirk: total full collections would be incremented when "complete" |
| // is set, by calling increment_total_collections above. However, we also need to |
| // account Full collections that had "complete" unset. |
| if (!complete) { |
| increment_total_full_collections(); |
| } |
| |
| CodeCache::on_gc_marking_cycle_start(); |
| |
| ClassUnloadingContext ctx(1 /* num_nmethod_unlink_workers */, |
| false /* unregister_nmethods_during_purge */, |
| false /* lock_codeblob_free_separately */); |
| |
| collect_generation(_old_gen, |
| full, |
| size, |
| is_tlab, |
| run_verification && VerifyGCLevel <= 1, |
| do_clear_all_soft_refs); |
| |
| CodeCache::on_gc_marking_cycle_finish(); |
| CodeCache::arm_all_nmethods(); |
| |
| // Adjust generation sizes. |
| _old_gen->compute_new_size(); |
| _young_gen->compute_new_size(); |
| |
| // Delete metaspaces for unloaded class loaders and clean up loader_data graph |
| ClassLoaderDataGraph::purge(true /* at_safepoint */); |
| DEBUG_ONLY(MetaspaceUtils::verify();) |
| |
| // Need to clear claim bits for the next mark. |
| ClassLoaderDataGraph::clear_claimed_marks(); |
| |
| // Resize the metaspace capacity after full collections |
| MetaspaceGC::compute_new_size(); |
| update_full_collections_completed(); |
| |
| print_heap_change(pre_gc_values); |
| |
| // Track memory usage and detect low memory after GC finishes |
| MemoryService::track_memory_usage(); |
| |
| // Need to tell the epilogue code we are done with Full GC, regardless what was |
| // the initial value for "complete" flag. |
| gc_epilogue(true); |
| |
| print_heap_after_gc(); |
| } |
| } |
| |
| bool GenCollectedHeap::should_do_full_collection(size_t size, bool full, bool is_tlab, |
| GenCollectedHeap::GenerationType max_gen) const { |
| return max_gen == OldGen && _old_gen->should_collect(full, size, is_tlab); |
| } |
| |
| void GenCollectedHeap::register_nmethod(nmethod* nm) { |
| ScavengableNMethods::register_nmethod(nm); |
| } |
| |
| void GenCollectedHeap::unregister_nmethod(nmethod* nm) { |
| ScavengableNMethods::unregister_nmethod(nm); |
| } |
| |
| void GenCollectedHeap::verify_nmethod(nmethod* nm) { |
| ScavengableNMethods::verify_nmethod(nm); |
| } |
| |
| void GenCollectedHeap::prune_scavengable_nmethods() { |
| ScavengableNMethods::prune_nmethods_not_into_young(); |
| } |
| |
| void GenCollectedHeap::prune_unlinked_nmethods() { |
| ScavengableNMethods::prune_unlinked_nmethods(); |
| } |
| |
| HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { |
| GCCauseSetter x(this, GCCause::_allocation_failure); |
| HeapWord* result = nullptr; |
| |
| assert(size != 0, "Precondition violated"); |
| if (GCLocker::is_active_and_needs_gc()) { |
| // GC locker is active; instead of a collection we will attempt |
| // to expand the heap, if there's room for expansion. |
| if (!is_maximal_no_gc()) { |
| result = expand_heap_and_allocate(size, is_tlab); |
| } |
| return result; // Could be null if we are out of space. |
| } else if (!incremental_collection_will_fail(false /* don't consult_young */)) { |
| // Do an incremental collection. |
| do_collection(false, // full |
| false, // clear_all_soft_refs |
| size, // size |
| is_tlab, // is_tlab |
| GenCollectedHeap::OldGen); // max_generation |
| } else { |
| log_trace(gc)(" :: Trying full because partial may fail :: "); |
| // Try a full collection; see delta for bug id 6266275 |
| // for the original code and why this has been simplified |
| // with from-space allocation criteria modified and |
| // such allocation moved out of the safepoint path. |
| do_collection(true, // full |
| false, // clear_all_soft_refs |
| size, // size |
| is_tlab, // is_tlab |
| GenCollectedHeap::OldGen); // max_generation |
| } |
| |
| result = attempt_allocation(size, is_tlab, false /*first_only*/); |
| |
| if (result != nullptr) { |
| assert(is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| // OK, collection failed, try expansion. |
| result = expand_heap_and_allocate(size, is_tlab); |
| if (result != nullptr) { |
| return result; |
| } |
| |
| // If we reach this point, we're really out of memory. Try every trick |
| // we can to reclaim memory. Force collection of soft references. Force |
| // a complete compaction of the heap. Any additional methods for finding |
| // free memory should be here, especially if they are expensive. If this |
| // attempt fails, an OOM exception will be thrown. |
| { |
| UIntFlagSetting flag_change(MarkSweepAlwaysCompactCount, 1); // Make sure the heap is fully compacted |
| |
| do_collection(true, // full |
| true, // clear_all_soft_refs |
| size, // size |
| is_tlab, // is_tlab |
| GenCollectedHeap::OldGen); // max_generation |
| } |
| |
| result = attempt_allocation(size, is_tlab, false /* first_only */); |
| if (result != nullptr) { |
| assert(is_in_reserved(result), "result not in heap"); |
| return result; |
| } |
| |
| assert(!soft_ref_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. |
| return nullptr; |
| } |
| |
| #ifdef ASSERT |
| class AssertNonScavengableClosure: public OopClosure { |
| public: |
| virtual void do_oop(oop* p) { |
| assert(!GenCollectedHeap::heap()->is_in_partial_collection(*p), |
| "Referent should not be scavengable."); } |
| virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); } |
| }; |
| static AssertNonScavengableClosure assert_is_non_scavengable_closure; |
| #endif |
| |
| void GenCollectedHeap::process_roots(ScanningOption so, |
| OopClosure* strong_roots, |
| CLDClosure* strong_cld_closure, |
| CLDClosure* weak_cld_closure, |
| CodeBlobToOopClosure* code_roots) { |
| // General roots. |
| assert(code_roots != nullptr, "code root closure should always be set"); |
| |
| ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure); |
| |
| // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway |
| CodeBlobToOopClosure* roots_from_code_p = (so & SO_AllCodeCache) ? nullptr : code_roots; |
| |
| Threads::oops_do(strong_roots, roots_from_code_p); |
| |
| OopStorageSet::strong_oops_do(strong_roots); |
| |
| if (so & SO_ScavengeCodeCache) { |
| assert(code_roots != nullptr, "must supply closure for code cache"); |
| |
| // We only visit parts of the CodeCache when scavenging. |
| ScavengableNMethods::nmethods_do(code_roots); |
| } |
| if (so & SO_AllCodeCache) { |
| assert(code_roots != nullptr, "must supply closure for code cache"); |
| |
| // CMSCollector uses this to do intermediate-strength collections. |
| // We scan the entire code cache, since CodeCache::do_unloading is not called. |
| CodeCache::blobs_do(code_roots); |
| } |
| // Verify that the code cache contents are not subject to |
| // movement by a scavenging collection. |
| DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations)); |
| DEBUG_ONLY(ScavengableNMethods::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable)); |
| } |
| |
| void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure) { |
| WeakProcessor::oops_do(root_closure); |
| } |
| |
| bool GenCollectedHeap::no_allocs_since_save_marks() { |
| return _young_gen->no_allocs_since_save_marks() && |
| _old_gen->no_allocs_since_save_marks(); |
| } |
| |
| // public collection interfaces |
| void GenCollectedHeap::collect(GCCause::Cause cause) { |
| // The caller doesn't have the Heap_lock |
| assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); |
| |
| unsigned int gc_count_before; |
| unsigned int full_gc_count_before; |
| |
| { |
| 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(); |
| } |
| |
| if (GCLocker::should_discard(cause, gc_count_before)) { |
| return; |
| } |
| |
| bool should_run_young_gc = (cause == GCCause::_wb_young_gc) |
| || (cause == GCCause::_gc_locker) |
| DEBUG_ONLY(|| (cause == GCCause::_scavenge_alot)); |
| |
| const GenerationType max_generation = should_run_young_gc |
| ? YoungGen |
| : OldGen; |
| |
| while (true) { |
| VM_GenCollectFull op(gc_count_before, full_gc_count_before, |
| cause, max_generation); |
| VMThread::execute(&op); |
| |
| if (!GCCause::is_explicit_full_gc(cause)) { |
| return; |
| } |
| |
| { |
| MutexLocker ml(Heap_lock); |
| // Read the GC count while holding the Heap_lock |
| if (full_gc_count_before != total_full_collections()) { |
| return; |
| } |
| } |
| |
| if (GCLocker::is_active_and_needs_gc()) { |
| // If GCLocker is active, wait until clear before retrying. |
| GCLocker::stall_until_clear(); |
| } |
| } |
| } |
| |
| void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs) { |
| do_full_collection(clear_all_soft_refs, OldGen); |
| } |
| |
| void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, |
| GenerationType last_generation) { |
| do_collection(true, // full |
| clear_all_soft_refs, // clear_all_soft_refs |
| 0, // size |
| false, // is_tlab |
| last_generation); // last_generation |
| // Hack XXX FIX ME !!! |
| // A scavenge may not have been attempted, or may have |
| // been attempted and failed, because the old gen was too full |
| if (gc_cause() == GCCause::_gc_locker && incremental_collection_failed()) { |
| log_debug(gc, jni)("GC locker: Trying a full collection because scavenge failed"); |
| // This time allow the old gen to be collected as well |
| do_collection(true, // full |
| clear_all_soft_refs, // clear_all_soft_refs |
| 0, // size |
| false, // is_tlab |
| OldGen); // last_generation |
| } |
| } |
| |
| bool GenCollectedHeap::is_in_young(const void* p) const { |
| bool result = p < _old_gen->reserved().start(); |
| assert(result == _young_gen->is_in_reserved(p), |
| "incorrect test - result=%d, p=" PTR_FORMAT, result, p2i(p)); |
| return result; |
| } |
| |
| bool GenCollectedHeap::requires_barriers(stackChunkOop obj) const { |
| return !is_in_young(obj); |
| } |
| |
| // Returns "TRUE" iff "p" points into the committed areas of the heap. |
| bool GenCollectedHeap::is_in(const void* p) const { |
| return _young_gen->is_in(p) || _old_gen->is_in(p); |
| } |
| |
| #ifdef ASSERT |
| // Don't implement this by using is_in_young(). This method is used |
| // in some cases to check that is_in_young() is correct. |
| bool GenCollectedHeap::is_in_partial_collection(const void* p) { |
| assert(is_in_reserved(p) || p == nullptr, |
| "Does not work if address is non-null and outside of the heap"); |
| return p < _young_gen->reserved().end() && p != nullptr; |
| } |
| #endif |
| |
| void GenCollectedHeap::oop_iterate(OopIterateClosure* cl) { |
| _young_gen->oop_iterate(cl); |
| _old_gen->oop_iterate(cl); |
| } |
| |
| void GenCollectedHeap::object_iterate(ObjectClosure* cl) { |
| _young_gen->object_iterate(cl); |
| _old_gen->object_iterate(cl); |
| } |
| |
| Space* GenCollectedHeap::space_containing(const void* addr) const { |
| Space* res = _young_gen->space_containing(addr); |
| if (res != nullptr) { |
| return res; |
| } |
| res = _old_gen->space_containing(addr); |
| assert(res != nullptr, "Could not find containing space"); |
| return res; |
| } |
| |
| HeapWord* GenCollectedHeap::block_start(const void* addr) const { |
| assert(is_in_reserved(addr), "block_start of address outside of heap"); |
| if (_young_gen->is_in_reserved(addr)) { |
| assert(_young_gen->is_in(addr), "addr should be in allocated part of generation"); |
| return _young_gen->block_start(addr); |
| } |
| |
| assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); |
| assert(_old_gen->is_in(addr), "addr should be in allocated part of generation"); |
| return _old_gen->block_start(addr); |
| } |
| |
| bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { |
| assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); |
| assert(block_start(addr) == addr, "addr must be a block start"); |
| if (_young_gen->is_in_reserved(addr)) { |
| return _young_gen->block_is_obj(addr); |
| } |
| |
| assert(_old_gen->is_in_reserved(addr), "Some generation should contain the address"); |
| return _old_gen->block_is_obj(addr); |
| } |
| |
| size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { |
| assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); |
| assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!"); |
| return _young_gen->tlab_capacity(); |
| } |
| |
| size_t GenCollectedHeap::tlab_used(Thread* thr) const { |
| assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); |
| assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!"); |
| return _young_gen->tlab_used(); |
| } |
| |
| size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { |
| assert(!_old_gen->supports_tlab_allocation(), "Old gen supports TLAB allocation?!"); |
| assert(_young_gen->supports_tlab_allocation(), "Young gen doesn't support TLAB allocation?!"); |
| return _young_gen->unsafe_max_tlab_alloc(); |
| } |
| |
| HeapWord* GenCollectedHeap::allocate_new_tlab(size_t min_size, |
| size_t requested_size, |
| size_t* actual_size) { |
| HeapWord* result = mem_allocate_work(requested_size /* size */, |
| true /* is_tlab */); |
| if (result != nullptr) { |
| *actual_size = requested_size; |
| } |
| |
| return result; |
| } |
| |
| // Requires "*prev_ptr" to be non-null. Deletes and a block of minimal size |
| // from the list headed by "*prev_ptr". |
| static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { |
| bool first = true; |
| size_t min_size = 0; // "first" makes this conceptually infinite. |
| ScratchBlock **smallest_ptr, *smallest; |
| ScratchBlock *cur = *prev_ptr; |
| while (cur) { |
| assert(*prev_ptr == cur, "just checking"); |
| if (first || cur->num_words < min_size) { |
| smallest_ptr = prev_ptr; |
| smallest = cur; |
| min_size = smallest->num_words; |
| first = false; |
| } |
| prev_ptr = &cur->next; |
| cur = cur->next; |
| } |
| smallest = *smallest_ptr; |
| *smallest_ptr = smallest->next; |
| return smallest; |
| } |
| |
| // Sort the scratch block list headed by res into decreasing size order, |
| // and set "res" to the result. |
| static void sort_scratch_list(ScratchBlock*& list) { |
| ScratchBlock* sorted = nullptr; |
| ScratchBlock* unsorted = list; |
| while (unsorted) { |
| ScratchBlock *smallest = removeSmallestScratch(&unsorted); |
| smallest->next = sorted; |
| sorted = smallest; |
| } |
| list = sorted; |
| } |
| |
| ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, |
| size_t max_alloc_words) { |
| ScratchBlock* res = nullptr; |
| _young_gen->contribute_scratch(res, requestor, max_alloc_words); |
| _old_gen->contribute_scratch(res, requestor, max_alloc_words); |
| sort_scratch_list(res); |
| return res; |
| } |
| |
| void GenCollectedHeap::release_scratch() { |
| _young_gen->reset_scratch(); |
| _old_gen->reset_scratch(); |
| } |
| |
| void GenCollectedHeap::prepare_for_verify() { |
| ensure_parsability(false); // no need to retire TLABs |
| } |
| |
| void GenCollectedHeap::generation_iterate(GenClosure* cl, |
| bool old_to_young) { |
| if (old_to_young) { |
| cl->do_generation(_old_gen); |
| cl->do_generation(_young_gen); |
| } else { |
| cl->do_generation(_young_gen); |
| cl->do_generation(_old_gen); |
| } |
| } |
| |
| bool GenCollectedHeap::is_maximal_no_gc() const { |
| return _young_gen->is_maximal_no_gc() && _old_gen->is_maximal_no_gc(); |
| } |
| |
| void GenCollectedHeap::save_marks() { |
| _young_gen->save_marks(); |
| _old_gen->save_marks(); |
| } |
| |
| GenCollectedHeap* GenCollectedHeap::heap() { |
| // SerialHeap is the only subtype of GenCollectedHeap. |
| return named_heap<GenCollectedHeap>(CollectedHeap::Serial); |
| } |
| |
| #if INCLUDE_SERIALGC |
| void GenCollectedHeap::prepare_for_compaction() { |
| // Start by compacting into same gen. |
| CompactPoint cp(_old_gen); |
| _old_gen->prepare_for_compaction(&cp); |
| _young_gen->prepare_for_compaction(&cp); |
| } |
| #endif // INCLUDE_SERIALGC |
| |
| void GenCollectedHeap::verify(VerifyOption option /* ignored */) { |
| log_debug(gc, verify)("%s", _old_gen->name()); |
| _old_gen->verify(); |
| |
| log_debug(gc, verify)("%s", _young_gen->name()); |
| _young_gen->verify(); |
| |
| log_debug(gc, verify)("RemSet"); |
| rem_set()->verify(); |
| } |
| |
| void GenCollectedHeap::print_on(outputStream* st) const { |
| if (_young_gen != nullptr) { |
| _young_gen->print_on(st); |
| } |
| if (_old_gen != nullptr) { |
| _old_gen->print_on(st); |
| } |
| MetaspaceUtils::print_on(st); |
| } |
| |
| void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { |
| } |
| |
| bool GenCollectedHeap::print_location(outputStream* st, void* addr) const { |
| return BlockLocationPrinter<GenCollectedHeap>::print_location(st, addr); |
| } |
| |
| void GenCollectedHeap::print_tracing_info() const { |
| if (log_is_enabled(Debug, gc, heap, exit)) { |
| LogStreamHandle(Debug, gc, heap, exit) lsh; |
| _young_gen->print_summary_info_on(&lsh); |
| _old_gen->print_summary_info_on(&lsh); |
| } |
| } |
| |
| void GenCollectedHeap::print_heap_change(const PreGenGCValues& pre_gc_values) const { |
| const DefNewGeneration* const def_new_gen = (DefNewGeneration*) young_gen(); |
| |
| log_info(gc, heap)(HEAP_CHANGE_FORMAT" " |
| HEAP_CHANGE_FORMAT" " |
| HEAP_CHANGE_FORMAT, |
| HEAP_CHANGE_FORMAT_ARGS(def_new_gen->short_name(), |
| pre_gc_values.young_gen_used(), |
| pre_gc_values.young_gen_capacity(), |
| def_new_gen->used(), |
| def_new_gen->capacity()), |
| HEAP_CHANGE_FORMAT_ARGS("Eden", |
| pre_gc_values.eden_used(), |
| pre_gc_values.eden_capacity(), |
| def_new_gen->eden()->used(), |
| def_new_gen->eden()->capacity()), |
| HEAP_CHANGE_FORMAT_ARGS("From", |
| pre_gc_values.from_used(), |
| pre_gc_values.from_capacity(), |
| def_new_gen->from()->used(), |
| def_new_gen->from()->capacity())); |
| log_info(gc, heap)(HEAP_CHANGE_FORMAT, |
| HEAP_CHANGE_FORMAT_ARGS(old_gen()->short_name(), |
| pre_gc_values.old_gen_used(), |
| pre_gc_values.old_gen_capacity(), |
| old_gen()->used(), |
| old_gen()->capacity())); |
| MetaspaceUtils::print_metaspace_change(pre_gc_values.metaspace_sizes()); |
| } |
| |
| class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { |
| private: |
| bool _full; |
| public: |
| void do_generation(Generation* gen) { |
| gen->gc_prologue(_full); |
| } |
| GenGCPrologueClosure(bool full) : _full(full) {}; |
| }; |
| |
| void GenCollectedHeap::gc_prologue(bool full) { |
| assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); |
| |
| // Fill TLAB's and such |
| ensure_parsability(true); // retire TLABs |
| |
| // Walk generations |
| GenGCPrologueClosure blk(full); |
| generation_iterate(&blk, false); // not old-to-young. |
| }; |
| |
| class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { |
| private: |
| bool _full; |
| public: |
| void do_generation(Generation* gen) { |
| gen->gc_epilogue(_full); |
| } |
| GenGCEpilogueClosure(bool full) : _full(full) {}; |
| }; |
| |
| void GenCollectedHeap::gc_epilogue(bool full) { |
| #if COMPILER2_OR_JVMCI |
| assert(DerivedPointerTable::is_empty(), "derived pointer present"); |
| #endif // COMPILER2_OR_JVMCI |
| |
| resize_all_tlabs(); |
| |
| GenGCEpilogueClosure blk(full); |
| generation_iterate(&blk, false); // not old-to-young. |
| |
| MetaspaceCounters::update_performance_counters(); |
| }; |
| |
| #ifndef PRODUCT |
| class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { |
| private: |
| public: |
| void do_generation(Generation* gen) { |
| gen->record_spaces_top(); |
| } |
| }; |
| |
| void GenCollectedHeap::record_gen_tops_before_GC() { |
| if (ZapUnusedHeapArea) { |
| GenGCSaveTopsBeforeGCClosure blk; |
| generation_iterate(&blk, false); // not old-to-young. |
| } |
| } |
| #endif // not PRODUCT |
| |
| class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { |
| public: |
| void do_generation(Generation* gen) { |
| gen->ensure_parsability(); |
| } |
| }; |
| |
| void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { |
| CollectedHeap::ensure_parsability(retire_tlabs); |
| GenEnsureParsabilityClosure ep_cl; |
| generation_iterate(&ep_cl, false); |
| } |
