--- /dev/null 2020-01-17 11:46:19.065201212 +0100 +++ new/src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp 2020-01-17 17:10:06.766130663 +0100 @@ -0,0 +1,2904 @@ +/* + * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved. + * + * 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 "memory/allocation.hpp" + +#include "gc/shared/gcTimer.hpp" +#include "gc/shared/gcTraceTime.inline.hpp" +#include "gc/shared/memAllocator.hpp" +#include "gc/shared/parallelCleaning.hpp" +#include "gc/shared/plab.hpp" + +#include "gc/shenandoah/shenandoahAllocTracker.hpp" +#include "gc/shenandoah/shenandoahBarrierSet.hpp" +#include "gc/shenandoah/shenandoahClosures.inline.hpp" +#include "gc/shenandoah/shenandoahCollectionSet.hpp" +#include "gc/shenandoah/shenandoahCollectorPolicy.hpp" +#include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" +#include "gc/shenandoah/shenandoahControlThread.hpp" +#include "gc/shenandoah/shenandoahFreeSet.hpp" +#include "gc/shenandoah/shenandoahPhaseTimings.hpp" +#include "gc/shenandoah/shenandoahHeap.inline.hpp" +#include "gc/shenandoah/shenandoahHeapRegion.hpp" +#include "gc/shenandoah/shenandoahHeapRegionSet.hpp" +#include "gc/shenandoah/shenandoahMarkCompact.hpp" +#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" +#include "gc/shenandoah/shenandoahMemoryPool.hpp" +#include "gc/shenandoah/shenandoahMetrics.hpp" +#include "gc/shenandoah/shenandoahMonitoringSupport.hpp" +#include "gc/shenandoah/shenandoahNormalMode.hpp" +#include "gc/shenandoah/shenandoahOopClosures.inline.hpp" +#include "gc/shenandoah/shenandoahPacer.inline.hpp" +#include "gc/shenandoah/shenandoahPassiveMode.hpp" +#include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" +#include "gc/shenandoah/shenandoahStringDedup.hpp" +#include "gc/shenandoah/shenandoahTaskqueue.hpp" +#include "gc/shenandoah/shenandoahTraversalMode.hpp" +#include "gc/shenandoah/shenandoahUtils.hpp" +#include "gc/shenandoah/shenandoahVerifier.hpp" +#include "gc/shenandoah/shenandoahCodeRoots.hpp" +#include "gc/shenandoah/shenandoahVMOperations.hpp" +#include "gc/shenandoah/shenandoahWorkGroup.hpp" +#include "gc/shenandoah/shenandoahWorkerPolicy.hpp" +#if INCLUDE_JFR +#include "gc/shenandoah/shenandoahJfrSupport.hpp" +#endif + +#include "memory/metaspace.hpp" +#include "runtime/vmThread.hpp" +#include "services/mallocTracker.hpp" + +#ifdef ASSERT +template +void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) { + T o = RawAccess<>::oop_load(p); + if (! CompressedOops::is_null(o)) { + oop obj = CompressedOops::decode_not_null(o); + shenandoah_assert_not_forwarded(p, obj); + } +} + +void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); } +void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); } +#endif + +class ShenandoahPretouchHeapTask : public AbstractGangTask { +private: + ShenandoahRegionIterator _regions; + const size_t _page_size; +public: + ShenandoahPretouchHeapTask(size_t page_size) : + AbstractGangTask("Shenandoah Pretouch Heap"), + _page_size(page_size) {} + + virtual void work(uint worker_id) { + ShenandoahHeapRegion* r = _regions.next(); + while (r != NULL) { + os::pretouch_memory(r->bottom(), r->end(), _page_size); + r = _regions.next(); + } + } +}; + +class ShenandoahPretouchBitmapTask : public AbstractGangTask { +private: + ShenandoahRegionIterator _regions; + char* _bitmap_base; + const size_t _bitmap_size; + const size_t _page_size; +public: + ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : + AbstractGangTask("Shenandoah Pretouch Bitmap"), + _bitmap_base(bitmap_base), + _bitmap_size(bitmap_size), + _page_size(page_size) {} + + virtual void work(uint worker_id) { + ShenandoahHeapRegion* r = _regions.next(); + while (r != NULL) { + size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); + size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); + assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); + + os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); + + r = _regions.next(); + } + } +}; + +jint ShenandoahHeap::initialize() { + initialize_heuristics(); + + // + // Figure out heap sizing + // + + size_t init_byte_size = collector_policy()->initial_heap_byte_size(); + size_t min_byte_size = collector_policy()->min_heap_byte_size(); + size_t max_byte_size = collector_policy()->max_heap_byte_size(); + size_t heap_alignment = collector_policy()->heap_alignment(); + + size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); + + if (ShenandoahAlwaysPreTouch) { + // Enabled pre-touch means the entire heap is committed right away. + init_byte_size = max_byte_size; + } + + Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); + Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); + + _num_regions = ShenandoahHeapRegion::region_count(); + + size_t num_committed_regions = init_byte_size / reg_size_bytes; + num_committed_regions = MIN2(num_committed_regions, _num_regions); + assert(num_committed_regions <= _num_regions, "sanity"); + _initial_size = num_committed_regions * reg_size_bytes; + + size_t num_min_regions = min_byte_size / reg_size_bytes; + num_min_regions = MIN2(num_min_regions, _num_regions); + assert(num_min_regions <= _num_regions, "sanity"); + _minimum_size = num_min_regions * reg_size_bytes; + + _committed = _initial_size; + + size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); + size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); + + // + // Reserve and commit memory for heap + // + + 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())); + _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); + _heap_region_special = heap_rs.special(); + + assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, + "Misaligned heap: " PTR_FORMAT, p2i(base())); + +#if SHENANDOAH_OPTIMIZED_OBJTASK + // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. + // Fail if we ever attempt to address more than we can. + if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) { + FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" + "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" + "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", + p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable()); + vm_exit_during_initialization("Fatal Error", buf); + } +#endif + + ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); + if (!_heap_region_special) { + os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, + "Cannot commit heap memory"); + } + + // + // Reserve and commit memory for bitmap(s) + // + + _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); + _bitmap_size = align_up(_bitmap_size, bitmap_page_size); + + size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); + + guarantee(bitmap_bytes_per_region != 0, + "Bitmap bytes per region should not be zero"); + guarantee(is_power_of_2(bitmap_bytes_per_region), + "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); + + if (bitmap_page_size > bitmap_bytes_per_region) { + _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; + _bitmap_bytes_per_slice = bitmap_page_size; + } else { + _bitmap_regions_per_slice = 1; + _bitmap_bytes_per_slice = bitmap_bytes_per_region; + } + + guarantee(_bitmap_regions_per_slice >= 1, + "Should have at least one region per slice: " SIZE_FORMAT, + _bitmap_regions_per_slice); + + guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, + "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, + _bitmap_bytes_per_slice, bitmap_page_size); + + ReservedSpace bitmap(_bitmap_size, bitmap_page_size); + MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); + _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); + _bitmap_region_special = bitmap.special(); + + size_t bitmap_init_commit = _bitmap_bytes_per_slice * + align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; + bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); + if (!_bitmap_region_special) { + os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, + "Cannot commit bitmap memory"); + } + + _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); + + if (ShenandoahVerify) { + ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); + if (!verify_bitmap.special()) { + os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, + "Cannot commit verification bitmap memory"); + } + MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); + MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); + _verification_bit_map.initialize(_heap_region, verify_bitmap_region); + _verifier = new ShenandoahVerifier(this, &_verification_bit_map); + } + + // Reserve aux bitmap for use in object_iterate(). We don't commit it here. + ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); + MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); + _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); + _aux_bitmap_region_special = aux_bitmap.special(); + _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); + + // + // Create regions and region sets + // + + _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); + _free_set = new ShenandoahFreeSet(this, _num_regions); + _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); + + { + ShenandoahHeapLocker locker(lock()); + + size_t size_words = ShenandoahHeapRegion::region_size_words(); + + for (size_t i = 0; i < _num_regions; i++) { + HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; + bool is_committed = i < num_committed_regions; + ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); + + _marking_context->initialize_top_at_mark_start(r); + _regions[i] = r; + assert(!collection_set()->is_in(i), "New region should not be in collection set"); + } + + // Initialize to complete + _marking_context->mark_complete(); + + _free_set->rebuild(); + } + + if (ShenandoahAlwaysPreTouch) { + assert(!AlwaysPreTouch, "Should have been overridden"); + + // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, + // before initialize() below zeroes it with initializing thread. For any given region, + // we touch the region and the corresponding bitmaps from the same thread. + ShenandoahPushWorkerScope scope(workers(), _max_workers, false); + + size_t pretouch_heap_page_size = heap_page_size; + size_t pretouch_bitmap_page_size = bitmap_page_size; + +#ifdef LINUX + // UseTransparentHugePages would madvise that backing memory can be coalesced into huge + // pages. But, the kernel needs to know that every small page is used, in order to coalesce + // them into huge one. Therefore, we need to pretouch with smaller pages. + if (UseTransparentHugePages) { + pretouch_heap_page_size = (size_t)os::vm_page_size(); + pretouch_bitmap_page_size = (size_t)os::vm_page_size(); + } +#endif + + // OS memory managers may want to coalesce back-to-back pages. Make their jobs + // simpler by pre-touching continuous spaces (heap and bitmap) separately. + + log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", + _num_regions, pretouch_bitmap_page_size); + ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); + _workers->run_task(&bcl); + + log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", + _num_regions, pretouch_heap_page_size); + ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); + _workers->run_task(&hcl); + } + + // + // Initialize the rest of GC subsystems + // + + BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); + + _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); + for (uint worker = 0; worker < _max_workers; worker++) { + _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); + Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); + } + + // The call below uses stuff (the SATB* things) that are in G1, but probably + // belong into a shared location. + ShenandoahBarrierSet::satb_mark_queue_set().initialize(SATB_Q_CBL_mon, + SATB_Q_FL_lock, + 20 /*G1SATBProcessCompletedThreshold */, + Shared_SATB_Q_lock); + + _monitoring_support = new ShenandoahMonitoringSupport(this); + _phase_timings = new ShenandoahPhaseTimings(); + ShenandoahStringDedup::initialize(); + ShenandoahCodeRoots::initialize(); + + if (ShenandoahAllocationTrace) { + _alloc_tracker = new ShenandoahAllocTracker(); + } + + if (ShenandoahPacing) { + _pacer = new ShenandoahPacer(this); + _pacer->setup_for_idle(); + } else { + _pacer = NULL; + } + + _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ? + new ShenandoahTraversalGC(this, _num_regions) : + NULL; + + _control_thread = new ShenandoahControlThread(); + + log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", + byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), + byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), + byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) + ); + + log_info(gc, init)("Safepointing mechanism: %s", + SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" : + (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown")); + + return JNI_OK; +} + +void ShenandoahHeap::initialize_heuristics() { + if (ShenandoahGCMode != NULL) { + if (strcmp(ShenandoahGCMode, "traversal") == 0) { + _gc_mode = new ShenandoahTraversalMode(); + } else if (strcmp(ShenandoahGCMode, "normal") == 0) { + _gc_mode = new ShenandoahNormalMode(); + } else if (strcmp(ShenandoahGCMode, "passive") == 0) { + _gc_mode = new ShenandoahPassiveMode(); + } else { + vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); + } + } else { + ShouldNotReachHere(); + } + _gc_mode->initialize_flags(); + _heuristics = _gc_mode->initialize_heuristics(); + + if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { + vm_exit_during_initialization( + err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", + _heuristics->name())); + } + if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { + vm_exit_during_initialization( + err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", + _heuristics->name())); + } + log_info(gc, init)("Shenandoah heuristics: %s", + _heuristics->name()); +} + +#ifdef _MSC_VER +#pragma warning( push ) +#pragma warning( disable:4355 ) // 'this' : used in base member initializer list +#endif + +ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : + CollectedHeap(), + _initial_size(0), + _used(0), + _committed(0), + _bytes_allocated_since_gc_start(0), + _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), + _workers(NULL), + _safepoint_workers(NULL), + _heap_region_special(false), + _num_regions(0), + _regions(NULL), + _update_refs_iterator(this), + _control_thread(NULL), + _shenandoah_policy(policy), + _heuristics(NULL), + _free_set(NULL), + _scm(new ShenandoahConcurrentMark()), + _traversal_gc(NULL), + _full_gc(new ShenandoahMarkCompact()), + _pacer(NULL), + _verifier(NULL), + _alloc_tracker(NULL), + _phase_timings(NULL), + _monitoring_support(NULL), + _memory_pool(NULL), + _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), + _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), + _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), + _soft_ref_policy(), + _ref_processor(NULL), + _marking_context(NULL), + _bitmap_size(0), + _bitmap_regions_per_slice(0), + _bitmap_bytes_per_slice(0), + _bitmap_region_special(false), + _aux_bitmap_region_special(false), + _liveness_cache(NULL), + _collection_set(NULL) +{ + log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); + log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); + + _max_workers = MAX2(_max_workers, 1U); + _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, + /* are_GC_task_threads */ true, + /* are_ConcurrentGC_threads */ true); + if (_workers == NULL) { + vm_exit_during_initialization("Failed necessary allocation."); + } else { + _workers->initialize_workers(); + } + + if (ShenandoahParallelSafepointThreads > 1) { + _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread", + ShenandoahParallelSafepointThreads, + /* are_GC_task_threads */ false, + /* are_ConcurrentGC_threads */ false); + _safepoint_workers->initialize_workers(); + } +} + +#ifdef _MSC_VER +#pragma warning( pop ) +#endif + +class ShenandoahResetBitmapTask : public AbstractGangTask { +private: + ShenandoahRegionIterator _regions; + +public: + ShenandoahResetBitmapTask() : + AbstractGangTask("Parallel Reset Bitmap Task") {} + + void work(uint worker_id) { + ShenandoahHeapRegion* region = _regions.next(); + ShenandoahHeap* heap = ShenandoahHeap::heap(); + ShenandoahMarkingContext* const ctx = heap->marking_context(); + while (region != NULL) { + if (heap->is_bitmap_slice_committed(region)) { + ctx->clear_bitmap(region); + } + region = _regions.next(); + } + } +}; + +void ShenandoahHeap::reset_mark_bitmap() { + assert_gc_workers(_workers->active_workers()); + mark_incomplete_marking_context(); + + ShenandoahResetBitmapTask task; + _workers->run_task(&task); +} + +void ShenandoahHeap::print_on(outputStream* st) const { + st->print_cr("Shenandoah Heap"); + st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", + byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), + byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), + byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); + st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", + num_regions(), + byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), + proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); + + st->print("Status: "); + if (has_forwarded_objects()) st->print("has forwarded objects, "); + if (is_concurrent_mark_in_progress()) st->print("marking, "); + if (is_evacuation_in_progress()) st->print("evacuating, "); + if (is_update_refs_in_progress()) st->print("updating refs, "); + if (is_concurrent_traversal_in_progress()) st->print("traversal, "); + if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); + if (is_full_gc_in_progress()) st->print("full gc, "); + if (is_full_gc_move_in_progress()) st->print("full gc move, "); + + if (cancelled_gc()) { + st->print("cancelled"); + } else { + st->print("not cancelled"); + } + st->cr(); + + st->print_cr("Reserved region:"); + st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", + p2i(reserved_region().start()), + p2i(reserved_region().end())); + + ShenandoahCollectionSet* cset = collection_set(); + st->print_cr("Collection set:"); + if (cset != NULL) { + st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); + st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); + } else { + st->print_cr(" (NULL)"); + } + + st->cr(); + MetaspaceUtils::print_on(st); + + if (Verbose) { + print_heap_regions_on(st); + } +} + +class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { +public: + void do_thread(Thread* thread) { + assert(thread != NULL, "Sanity"); + assert(thread->is_Worker_thread(), "Only worker thread expected"); + ShenandoahThreadLocalData::initialize_gclab(thread); + } +}; + +void ShenandoahHeap::post_initialize() { + CollectedHeap::post_initialize(); + MutexLocker ml(Threads_lock); + + ShenandoahInitWorkerGCLABClosure init_gclabs; + _workers->threads_do(&init_gclabs); + + // gclab can not be initialized early during VM startup, as it can not determinate its max_size. + // Now, we will let WorkGang to initialize gclab when new worker is created. + _workers->set_initialize_gclab(); + + _scm->initialize(_max_workers); + _full_gc->initialize(_gc_timer); + + ref_processing_init(); + + _heuristics->initialize(); + + JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); +} + +size_t ShenandoahHeap::used() const { + return OrderAccess::load_acquire(&_used); +} + +size_t ShenandoahHeap::committed() const { + OrderAccess::acquire(); + return _committed; +} + +void ShenandoahHeap::increase_committed(size_t bytes) { + assert_heaplock_or_safepoint(); + _committed += bytes; +} + +void ShenandoahHeap::decrease_committed(size_t bytes) { + assert_heaplock_or_safepoint(); + _committed -= bytes; +} + +void ShenandoahHeap::increase_used(size_t bytes) { + Atomic::add(bytes, &_used); +} + +void ShenandoahHeap::set_used(size_t bytes) { + OrderAccess::release_store_fence(&_used, bytes); +} + +void ShenandoahHeap::decrease_used(size_t bytes) { + assert(used() >= bytes, "never decrease heap size by more than we've left"); + Atomic::sub(bytes, &_used); +} + +void ShenandoahHeap::increase_allocated(size_t bytes) { + Atomic::add(bytes, &_bytes_allocated_since_gc_start); +} + +void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { + size_t bytes = words * HeapWordSize; + if (!waste) { + increase_used(bytes); + } + increase_allocated(bytes); + if (ShenandoahPacing) { + control_thread()->pacing_notify_alloc(words); + if (waste) { + pacer()->claim_for_alloc(words, true); + } + } +} + +size_t ShenandoahHeap::capacity() const { + return committed(); +} + +size_t ShenandoahHeap::max_capacity() const { + return _num_regions * ShenandoahHeapRegion::region_size_bytes(); +} + +size_t ShenandoahHeap::min_capacity() const { + return _minimum_size; +} + +size_t ShenandoahHeap::initial_capacity() const { + return _initial_size; +} + +bool ShenandoahHeap::is_in(const void* p) const { + HeapWord* heap_base = (HeapWord*) base(); + HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); + return p >= heap_base && p < last_region_end; +} + +void ShenandoahHeap::op_uncommit(double shrink_before) { + assert (ShenandoahUncommit, "should be enabled"); + + // Application allocates from the beginning of the heap, and GC allocates at + // the end of it. It is more efficient to uncommit from the end, so that applications + // could enjoy the near committed regions. GC allocations are much less frequent, + // and therefore can accept the committing costs. + + size_t count = 0; + for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow + ShenandoahHeapRegion* r = get_region(i - 1); + if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { + ShenandoahHeapLocker locker(lock()); + if (r->is_empty_committed()) { + // Do not uncommit below minimal capacity + if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { + break; + } + + r->make_uncommitted(); + count++; + } + } + SpinPause(); // allow allocators to take the lock + } + + if (count > 0) { + control_thread()->notify_heap_changed(); + } +} + +HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { + // New object should fit the GCLAB size + size_t min_size = MAX2(size, PLAB::min_size()); + + // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. + size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; + new_size = MIN2(new_size, PLAB::max_size()); + new_size = MAX2(new_size, PLAB::min_size()); + + // Record new heuristic value even if we take any shortcut. This captures + // the case when moderately-sized objects always take a shortcut. At some point, + // heuristics should catch up with them. + ShenandoahThreadLocalData::set_gclab_size(thread, new_size); + + if (new_size < size) { + // New size still does not fit the object. Fall back to shared allocation. + // This avoids retiring perfectly good GCLABs, when we encounter a large object. + return NULL; + } + + // Retire current GCLAB, and allocate a new one. + PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); + gclab->retire(); + + size_t actual_size = 0; + HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); + if (gclab_buf == NULL) { + return NULL; + } + + assert (size <= actual_size, "allocation should fit"); + + if (ZeroTLAB) { + // ..and clear it. + Copy::zero_to_words(gclab_buf, actual_size); + } else { + // ...and zap just allocated object. +#ifdef ASSERT + // Skip mangling the space corresponding to the object header to + // ensure that the returned space is not considered parsable by + // any concurrent GC thread. + size_t hdr_size = oopDesc::header_size(); + Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); +#endif // ASSERT + } + gclab->set_buf(gclab_buf, actual_size); + return gclab->allocate(size); +} + +HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, + size_t requested_size, + size_t* actual_size) { + ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); + HeapWord* res = allocate_memory(req); + if (res != NULL) { + *actual_size = req.actual_size(); + } else { + *actual_size = 0; + } + return res; +} + +HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, + size_t word_size, + size_t* actual_size) { + ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); + HeapWord* res = allocate_memory(req); + if (res != NULL) { + *actual_size = req.actual_size(); + } else { + *actual_size = 0; + } + return res; +} + +ShenandoahHeap* ShenandoahHeap::heap() { + CollectedHeap* heap = Universe::heap(); + assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); + assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap"); + return (ShenandoahHeap*) heap; +} + +ShenandoahHeap* ShenandoahHeap::heap_no_check() { + CollectedHeap* heap = Universe::heap(); + return (ShenandoahHeap*) heap; +} + +HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { + ShenandoahAllocTrace trace_alloc(req.size(), req.type()); + + intptr_t pacer_epoch = 0; + bool in_new_region = false; + HeapWord* result = NULL; + + if (req.is_mutator_alloc()) { + if (ShenandoahPacing) { + pacer()->pace_for_alloc(req.size()); + pacer_epoch = pacer()->epoch(); + } + + if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { + result = allocate_memory_under_lock(req, in_new_region); + } + + // Allocation failed, block until control thread reacted, then retry allocation. + // + // It might happen that one of the threads requesting allocation would unblock + // way later after GC happened, only to fail the second allocation, because + // other threads have already depleted the free storage. In this case, a better + // strategy is to try again, as long as GC makes progress. + // + // Then, we need to make sure the allocation was retried after at least one + // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. + + size_t tries = 0; + + while (result == NULL && _progress_last_gc.is_set()) { + tries++; + control_thread()->handle_alloc_failure(req.size()); + result = allocate_memory_under_lock(req, in_new_region); + } + + while (result == NULL && tries <= ShenandoahFullGCThreshold) { + tries++; + control_thread()->handle_alloc_failure(req.size()); + result = allocate_memory_under_lock(req, in_new_region); + } + + } else { + assert(req.is_gc_alloc(), "Can only accept GC allocs here"); + result = allocate_memory_under_lock(req, in_new_region); + // Do not call handle_alloc_failure() here, because we cannot block. + // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). + } + + if (in_new_region) { + control_thread()->notify_heap_changed(); + } + + if (result != NULL) { + size_t requested = req.size(); + size_t actual = req.actual_size(); + + assert (req.is_lab_alloc() || (requested == actual), + "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, + ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); + + if (req.is_mutator_alloc()) { + notify_mutator_alloc_words(actual, false); + + // If we requested more than we were granted, give the rest back to pacer. + // This only matters if we are in the same pacing epoch: do not try to unpace + // over the budget for the other phase. + if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { + pacer()->unpace_for_alloc(pacer_epoch, requested - actual); + } + } else { + increase_used(actual*HeapWordSize); + } + } + + return result; +} + +HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { + ShenandoahHeapLocker locker(lock()); + return _free_set->allocate(req, in_new_region); +} + +HeapWord* ShenandoahHeap::mem_allocate(size_t size, + bool* gc_overhead_limit_was_exceeded) { + ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); + return allocate_memory(req); +} + +MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, + size_t size, + Metaspace::MetadataType mdtype) { + MetaWord* result; + + // Inform metaspace OOM to GC heuristics if class unloading is possible. + if (heuristics()->can_unload_classes()) { + ShenandoahHeuristics* h = heuristics(); + h->record_metaspace_oom(); + } + + // Expand and retry allocation + result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); + if (result != NULL) { + return result; + } + + // Start full GC + collect(GCCause::_metadata_GC_clear_soft_refs); + + // Retry allocation + result = loader_data->metaspace_non_null()->allocate(size, mdtype); + if (result != NULL) { + return result; + } + + // Expand and retry allocation + result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); + if (result != NULL) { + return result; + } + + // Out of memory + return NULL; +} + +class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { +private: + ShenandoahHeap* const _heap; + Thread* const _thread; +public: + ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : + _heap(heap), _thread(Thread::current()) {} + + void do_object(oop p) { + shenandoah_assert_marked(NULL, p); + if (!p->is_forwarded()) { + _heap->evacuate_object(p, _thread); + } + } +}; + +class ShenandoahEvacuationTask : public AbstractGangTask { +private: + ShenandoahHeap* const _sh; + ShenandoahCollectionSet* const _cs; + bool _concurrent; +public: + ShenandoahEvacuationTask(ShenandoahHeap* sh, + ShenandoahCollectionSet* cs, + bool concurrent) : + AbstractGangTask("Parallel Evacuation Task"), + _sh(sh), + _cs(cs), + _concurrent(concurrent) + {} + + void work(uint worker_id) { + if (_concurrent) { + ShenandoahConcurrentWorkerSession worker_session(worker_id); + ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); + ShenandoahEvacOOMScope oom_evac_scope; + do_work(); + } else { + ShenandoahParallelWorkerSession worker_session(worker_id); + ShenandoahEvacOOMScope oom_evac_scope; + do_work(); + } + } + +private: + void do_work() { + ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); + ShenandoahHeapRegion* r; + while ((r =_cs->claim_next()) != NULL) { + assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->region_number()); + _sh->marked_object_iterate(r, &cl); + + if (ShenandoahPacing) { + _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); + } + + if (_sh->check_cancelled_gc_and_yield(_concurrent)) { + break; + } + } + } +}; + +void ShenandoahHeap::trash_cset_regions() { + ShenandoahHeapLocker locker(lock()); + + ShenandoahCollectionSet* set = collection_set(); + ShenandoahHeapRegion* r; + set->clear_current_index(); + while ((r = set->next()) != NULL) { + r->make_trash(); + } + collection_set()->clear(); +} + +void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { + st->print_cr("Heap Regions:"); + st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); + st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); + st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); + st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)"); + + for (size_t i = 0; i < num_regions(); i++) { + get_region(i)->print_on(st); + } +} + +void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { + assert(start->is_humongous_start(), "reclaim regions starting with the first one"); + + oop humongous_obj = oop(start->bottom()); + size_t size = humongous_obj->size(); + size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); + size_t index = start->region_number() + required_regions - 1; + + assert(!start->has_live(), "liveness must be zero"); + + for(size_t i = 0; i < required_regions; i++) { + // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, + // as it expects that every region belongs to a humongous region starting with a humongous start region. + ShenandoahHeapRegion* region = get_region(index --); + + assert(region->is_humongous(), "expect correct humongous start or continuation"); + assert(!region->is_cset(), "Humongous region should not be in collection set"); + + region->make_trash_immediate(); + } +} + +class ShenandoahRetireGCLABClosure : public ThreadClosure { +public: + void do_thread(Thread* thread) { + PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); + assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); + gclab->retire(); + } +}; + +void ShenandoahHeap::make_parsable(bool retire_tlabs) { + if (UseTLAB) { + CollectedHeap::ensure_parsability(retire_tlabs); + } + ShenandoahRetireGCLABClosure cl; + for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { + cl.do_thread(t); + } + workers()->threads_do(&cl); +} + +void ShenandoahHeap::resize_tlabs() { + CollectedHeap::resize_all_tlabs(); +} + +void ShenandoahHeap::accumulate_statistics_tlabs() { + CollectedHeap::accumulate_statistics_all_tlabs(); +} + +class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { +private: + ShenandoahRootEvacuator* _rp; + +public: + ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : + AbstractGangTask("Shenandoah evacuate and update roots"), + _rp(rp) {} + + void work(uint worker_id) { + ShenandoahParallelWorkerSession worker_session(worker_id); + ShenandoahEvacOOMScope oom_evac_scope; + ShenandoahEvacuateUpdateRootsClosure cl; + MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); + _rp->roots_do(worker_id, &cl); + } +}; + +void ShenandoahHeap::evacuate_and_update_roots() { +#if COMPILER2_OR_JVMCI + DerivedPointerTable::clear(); +#endif + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); + + { + ShenandoahRootEvacuator rp(workers()->active_workers(), ShenandoahPhaseTimings::init_evac); + ShenandoahEvacuateUpdateRootsTask roots_task(&rp); + workers()->run_task(&roots_task); + } + +#if COMPILER2_OR_JVMCI + DerivedPointerTable::update_pointers(); +#endif +} + +// Returns size in bytes +size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { + if (ShenandoahElasticTLAB) { + // With Elastic TLABs, return the max allowed size, and let the allocation path + // figure out the safe size for current allocation. + return ShenandoahHeapRegion::max_tlab_size_bytes(); + } else { + return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); + } +} + +size_t ShenandoahHeap::max_tlab_size() const { + // Returns size in words + return ShenandoahHeapRegion::max_tlab_size_words(); +} + +class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure { +public: + void do_thread(Thread* thread) { + PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); + gclab->retire(); + if (ShenandoahThreadLocalData::gclab_size(thread) > 0) { + ShenandoahThreadLocalData::set_gclab_size(thread, 0); + } + } +}; + +void ShenandoahHeap::retire_and_reset_gclabs() { + ShenandoahRetireAndResetGCLABClosure cl; + for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { + cl.do_thread(t); + } + workers()->threads_do(&cl); +} + +void ShenandoahHeap::collect(GCCause::Cause cause) { + control_thread()->request_gc(cause); +} + +void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { + //assert(false, "Shouldn't need to do full collections"); +} + +CollectorPolicy* ShenandoahHeap::collector_policy() const { + return _shenandoah_policy; +} + +HeapWord* ShenandoahHeap::block_start(const void* addr) const { + Space* sp = heap_region_containing(addr); + if (sp != NULL) { + return sp->block_start(addr); + } + return NULL; +} + +size_t ShenandoahHeap::block_size(const HeapWord* addr) const { + Space* sp = heap_region_containing(addr); + assert(sp != NULL, "block_size of address outside of heap"); + return sp->block_size(addr); +} + +bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { + Space* sp = heap_region_containing(addr); + return sp->block_is_obj(addr); +} + +jlong ShenandoahHeap::millis_since_last_gc() { + double v = heuristics()->time_since_last_gc() * 1000; + assert(0 <= v && v <= max_jlong, "value should fit: %f", v); + return (jlong)v; +} + +void ShenandoahHeap::prepare_for_verify() { + if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) { + make_parsable(false); + } +} + +void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { + workers()->print_worker_threads_on(st); + if (ShenandoahStringDedup::is_enabled()) { + ShenandoahStringDedup::print_worker_threads_on(st); + } +} + +void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { + workers()->threads_do(tcl); + if (_safepoint_workers != NULL) { + _safepoint_workers->threads_do(tcl); + } + if (ShenandoahStringDedup::is_enabled()) { + ShenandoahStringDedup::threads_do(tcl); + } +} + +void ShenandoahHeap::print_tracing_info() const { + LogTarget(Info, gc, stats) lt; + if (lt.is_enabled()) { + ResourceMark rm; + LogStream ls(lt); + + phase_timings()->print_on(&ls); + + ls.cr(); + ls.cr(); + + shenandoah_policy()->print_gc_stats(&ls); + + ls.cr(); + ls.cr(); + + if (ShenandoahPacing) { + pacer()->print_on(&ls); + } + + ls.cr(); + ls.cr(); + + if (ShenandoahAllocationTrace) { + assert(alloc_tracker() != NULL, "Must be"); + alloc_tracker()->print_on(&ls); + } else { + ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); + } + } +} + +void ShenandoahHeap::verify(VerifyOption vo) { + if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { + if (ShenandoahVerify) { + verifier()->verify_generic(vo); + } else { + // TODO: Consider allocating verification bitmaps on demand, + // and turn this on unconditionally. + } + } +} +size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { + return _free_set->capacity(); +} + +class ObjectIterateScanRootClosure : public BasicOopIterateClosure { +private: + MarkBitMap* _bitmap; + Stack* _oop_stack; + + template + void do_oop_work(T* p) { + T o = RawAccess<>::oop_load(p); + if (!CompressedOops::is_null(o)) { + oop obj = CompressedOops::decode_not_null(o); + oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); + if (fwd == NULL) { + // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp. + // + // That operation walks the reachable objects on its own, storing the marking + // wavefront in the object marks. When it is done, it calls the CollectedHeap + // to iterate over all objects to clean up the mess. When it reaches here, + // the Shenandoah fwdptr resolution code encounters the marked objects with + // NULL forwardee. Trying to act on that would crash the VM. Or fail the + // asserts, should we go for resolve_forwarded_pointer(obj). + // + // Therefore, we have to dodge it by doing the raw access to forwardee, and + // assuming the object had no forwardee, if that thing is NULL. + } else { + obj = fwd; + } + assert(oopDesc::is_oop(obj), "must be a valid oop"); + if (!_bitmap->isMarked((HeapWord*) obj)) { + _bitmap->mark((HeapWord*) obj); + _oop_stack->push(obj); + } + } + } +public: + ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack* oop_stack) : + _bitmap(bitmap), _oop_stack(oop_stack) {} + void do_oop(oop* p) { do_oop_work(p); } + void do_oop(narrowOop* p) { do_oop_work(p); } +}; + +/* + * This is public API, used in preparation of object_iterate(). + * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't + * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can + * control, we call SH::make_tlabs_parsable(). + */ +void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { + // No-op. +} + +/* + * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. + * + * We cannot safely iterate objects by doing a linear scan at random points in time. Linear + * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. + * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear + * scanning therefore depends on having a valid marking bitmap to support it. However, we only + * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid + * marking bitmap during marking, after aborted marking or during/after cleanup (when we just + * wiped the bitmap in preparation for next marking). + * + * For all those reasons, we implement object iteration as a single marking traversal, reporting + * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap + * is allowed to report dead objects, but is not required to do so. + */ +void ShenandoahHeap::object_iterate(ObjectClosure* cl) { + assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); + if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { + log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); + return; + } + + // Reset bitmap + _aux_bit_map.clear(); + + Stack oop_stack; + + // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects. + ShenandoahHeapIterationRootScanner rp; + ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); + + // If we are unloading classes right now, we should not touch weak roots, + // on the off-chance we would evacuate them and make them live accidentally. + // In other cases, we have to scan all roots. + if (is_evacuation_in_progress() && unload_classes()) { + rp.strong_roots_do(&oops); + } else { + rp.roots_do(&oops); + } + + // Work through the oop stack to traverse heap. + while (! oop_stack.is_empty()) { + oop obj = oop_stack.pop(); + assert(oopDesc::is_oop(obj), "must be a valid oop"); + cl->do_object(obj); + obj->oop_iterate(&oops); + } + + assert(oop_stack.is_empty(), "should be empty"); + + if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { + log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); + } +} + +void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) { + assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); + object_iterate(cl); +} + +void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { + for (size_t i = 0; i < num_regions(); i++) { + ShenandoahHeapRegion* current = get_region(i); + blk->heap_region_do(current); + } +} + +class ShenandoahParallelHeapRegionTask : public AbstractGangTask { +private: + ShenandoahHeap* const _heap; + ShenandoahHeapRegionClosure* const _blk; + + DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t)); + volatile size_t _index; + DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0); + +public: + ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : + AbstractGangTask("Parallel Region Task"), + _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} + + void work(uint worker_id) { + size_t stride = ShenandoahParallelRegionStride; + + size_t max = _heap->num_regions(); + while (_index < max) { + size_t cur = Atomic::add(stride, &_index) - stride; + size_t start = cur; + size_t end = MIN2(cur + stride, max); + if (start >= max) break; + + for (size_t i = cur; i < end; i++) { + ShenandoahHeapRegion* current = _heap->get_region(i); + _blk->heap_region_do(current); + } + } + } +}; + +void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { + assert(blk->is_thread_safe(), "Only thread-safe closures here"); + if (num_regions() > ShenandoahParallelRegionStride) { + ShenandoahParallelHeapRegionTask task(blk); + workers()->run_task(&task); + } else { + heap_region_iterate(blk); + } +} + +class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { +private: + ShenandoahMarkingContext* const _ctx; +public: + ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} + + void heap_region_do(ShenandoahHeapRegion* r) { + if (r->is_active()) { + r->clear_live_data(); + _ctx->capture_top_at_mark_start(r); + } else { + assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); + assert(_ctx->top_at_mark_start(r) == r->top(), + "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()); + } + } + + bool is_thread_safe() { return true; } +}; + +void ShenandoahHeap::op_init_mark() { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); + assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); + + assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); + assert(!marking_context()->is_complete(), "should not be complete"); + + if (ShenandoahVerify) { + verifier()->verify_before_concmark(); + } + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats); + accumulate_statistics_tlabs(); + } + + if (VerifyBeforeGC) { + Universe::verify(); + } + + set_concurrent_mark_in_progress(true); + // We need to reset all TLABs because we'd lose marks on all objects allocated in them. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); + make_parsable(true); + } + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); + ShenandoahClearLivenessClosure clc; + parallel_heap_region_iterate(&clc); + } + + // Make above changes visible to worker threads + OrderAccess::fence(); + + concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); + + if (UseTLAB) { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); + resize_tlabs(); + } + + if (ShenandoahPacing) { + pacer()->setup_for_mark(); + } +} + +void ShenandoahHeap::op_mark() { + concurrent_mark()->mark_from_roots(); +} + +class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { +private: + ShenandoahMarkingContext* const _ctx; +public: + ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} + + void heap_region_do(ShenandoahHeapRegion* r) { + if (r->is_active()) { + HeapWord *tams = _ctx->top_at_mark_start(r); + HeapWord *top = r->top(); + if (top > tams) { + r->increase_live_data_alloc_words(pointer_delta(top, tams)); + } + } else { + assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); + assert(_ctx->top_at_mark_start(r) == r->top(), + "Region " SIZE_FORMAT " should have correct TAMS", r->region_number()); + } + } + + bool is_thread_safe() { return true; } +}; + +void ShenandoahHeap::op_final_mark() { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); + + // It is critical that we + // evacuate roots right after finishing marking, so that we don't + // get unmarked objects in the roots. + + if (!cancelled_gc()) { + concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); + + if (has_forwarded_objects()) { + // Degen may be caused by failed evacuation of roots + if (is_degenerated_gc_in_progress()) { + concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); + } else { + concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots); + } + } + + if (ShenandoahVerify) { + verifier()->verify_roots_no_forwarded(); + } + + stop_concurrent_marking(); + + // All allocations past TAMS are implicitly live, adjust the region data. + // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); + ShenandoahCompleteLivenessClosure cl; + parallel_heap_region_iterate(&cl); + } + + // Force the threads to reacquire their TLABs outside the collection set. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs); + make_parsable(true); + } + + // We are about to select the collection set, make sure it knows about + // current pinning status. Also, this allows trashing more regions that + // now have their pinning status dropped. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned); + sync_pinned_region_status(); + } + + // Trash the collection set left over from previous cycle, if any. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset); + trash_cset_regions(); + } + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac); + + ShenandoahHeapLocker locker(lock()); + _collection_set->clear(); + _free_set->clear(); + + heuristics()->choose_collection_set(_collection_set); + + _free_set->rebuild(); + } + + // If collection set has candidates, start evacuation. + // Otherwise, bypass the rest of the cycle. + if (!collection_set()->is_empty()) { + ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); + + if (ShenandoahVerify) { + verifier()->verify_before_evacuation(); + } + + set_evacuation_in_progress(true); + // From here on, we need to update references. + set_has_forwarded_objects(true); + + if (!is_degenerated_gc_in_progress()) { + evacuate_and_update_roots(); + } + + if (ShenandoahPacing) { + pacer()->setup_for_evac(); + } + + if (ShenandoahVerify) { + verifier()->verify_roots_no_forwarded(); + verifier()->verify_during_evacuation(); + } + } else { + if (ShenandoahVerify) { + verifier()->verify_after_concmark(); + } + + if (VerifyAfterGC) { + Universe::verify(); + } + } + + } else { + concurrent_mark()->cancel(); + stop_concurrent_marking(); + + if (process_references()) { + // Abandon reference processing right away: pre-cleaning must have failed. + ReferenceProcessor *rp = ref_processor(); + rp->disable_discovery(); + rp->abandon_partial_discovery(); + rp->verify_no_references_recorded(); + } + } +} + +void ShenandoahHeap::op_final_evac() { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); + + set_evacuation_in_progress(false); + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_retire_gclabs); + retire_and_reset_gclabs(); + } + + if (ShenandoahVerify) { + verifier()->verify_after_evacuation(); + } + + if (VerifyAfterGC) { + Universe::verify(); + } +} + +void ShenandoahHeap::op_conc_evac() { + ShenandoahEvacuationTask task(this, _collection_set, true); + workers()->run_task(&task); +} + +void ShenandoahHeap::op_stw_evac() { + ShenandoahEvacuationTask task(this, _collection_set, false); + workers()->run_task(&task); +} + +void ShenandoahHeap::op_updaterefs() { + update_heap_references(true); +} + +void ShenandoahHeap::op_cleanup() { + free_set()->recycle_trash(); +} + +void ShenandoahHeap::op_reset() { + reset_mark_bitmap(); +} + +void ShenandoahHeap::op_preclean() { + concurrent_mark()->preclean_weak_refs(); +} + +void ShenandoahHeap::op_init_traversal() { + traversal_gc()->init_traversal_collection(); +} + +void ShenandoahHeap::op_traversal() { + traversal_gc()->concurrent_traversal_collection(); +} + +void ShenandoahHeap::op_final_traversal() { + traversal_gc()->final_traversal_collection(); +} + +void ShenandoahHeap::op_full(GCCause::Cause cause) { + ShenandoahMetricsSnapshot metrics; + metrics.snap_before(); + + full_gc()->do_it(cause); + if (UseTLAB) { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs); + resize_all_tlabs(); + } + + metrics.snap_after(); + + if (metrics.is_good_progress()) { + _progress_last_gc.set(); + } else { + // Nothing to do. Tell the allocation path that we have failed to make + // progress, and it can finally fail. + _progress_last_gc.unset(); + } +} + +void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { + // Degenerated GC is STW, but it can also fail. Current mechanics communicates + // GC failure via cancelled_concgc() flag. So, if we detect the failure after + // some phase, we have to upgrade the Degenerate GC to Full GC. + + clear_cancelled_gc(); + + ShenandoahMetricsSnapshot metrics; + metrics.snap_before(); + + switch (point) { + case _degenerated_traversal: + { + // Drop the collection set. Note: this leaves some already forwarded objects + // behind, which may be problematic, see comments for ShenandoahEvacAssist + // workarounds in ShenandoahTraversalHeuristics. + + ShenandoahHeapLocker locker(lock()); + collection_set()->clear_current_index(); + for (size_t i = 0; i < collection_set()->count(); i++) { + ShenandoahHeapRegion* r = collection_set()->next(); + r->make_regular_bypass(); + } + collection_set()->clear(); + } + op_final_traversal(); + op_cleanup(); + return; + + // The cases below form the Duff's-like device: it describes the actual GC cycle, + // but enters it at different points, depending on which concurrent phase had + // degenerated. + + case _degenerated_outside_cycle: + // We have degenerated from outside the cycle, which means something is bad with + // the heap, most probably heavy humongous fragmentation, or we are very low on free + // space. It makes little sense to wait for Full GC to reclaim as much as it can, when + // we can do the most aggressive degen cycle, which includes processing references and + // class unloading, unless those features are explicitly disabled. + // + // Note that we can only do this for "outside-cycle" degens, otherwise we would risk + // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. + set_process_references(heuristics()->can_process_references()); + set_unload_classes(heuristics()->can_unload_classes()); + + if (is_traversal_mode()) { + // Not possible to degenerate from here, upgrade to Full GC right away. + cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); + op_degenerated_fail(); + return; + } + + op_reset(); + + op_init_mark(); + if (cancelled_gc()) { + op_degenerated_fail(); + return; + } + + case _degenerated_mark: + op_final_mark(); + if (cancelled_gc()) { + op_degenerated_fail(); + return; + } + + op_cleanup(); + + case _degenerated_evac: + // If heuristics thinks we should do the cycle, this flag would be set, + // and we can do evacuation. Otherwise, it would be the shortcut cycle. + if (is_evacuation_in_progress()) { + + // Degeneration under oom-evac protocol might have left some objects in + // collection set un-evacuated. Restart evacuation from the beginning to + // capture all objects. For all the objects that are already evacuated, + // it would be a simple check, which is supposed to be fast. This is also + // safe to do even without degeneration, as CSet iterator is at beginning + // in preparation for evacuation anyway. + // + // Before doing that, we need to make sure we never had any cset-pinned + // regions. This may happen if allocation failure happened when evacuating + // the about-to-be-pinned object, oom-evac protocol left the object in + // the collection set, and then the pin reached the cset region. If we continue + // the cycle here, we would trash the cset and alive objects in it. To avoid + // it, we fail degeneration right away and slide into Full GC to recover. + + { + sync_pinned_region_status(); + collection_set()->clear_current_index(); + + ShenandoahHeapRegion* r; + while ((r = collection_set()->next()) != NULL) { + if (r->is_pinned()) { + cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); + op_degenerated_fail(); + return; + } + } + + collection_set()->clear_current_index(); + } + + op_stw_evac(); + if (cancelled_gc()) { + op_degenerated_fail(); + return; + } + } + + // If heuristics thinks we should do the cycle, this flag would be set, + // and we need to do update-refs. Otherwise, it would be the shortcut cycle. + if (has_forwarded_objects()) { + op_init_updaterefs(); + if (cancelled_gc()) { + op_degenerated_fail(); + return; + } + } + + case _degenerated_updaterefs: + if (has_forwarded_objects()) { + op_final_updaterefs(); + if (cancelled_gc()) { + op_degenerated_fail(); + return; + } + } + + op_cleanup(); + break; + + default: + ShouldNotReachHere(); + } + + if (ShenandoahVerify) { + verifier()->verify_after_degenerated(); + } + + if (VerifyAfterGC) { + Universe::verify(); + } + + metrics.snap_after(); + + // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, + // because that probably means the heap is overloaded and/or fragmented. + if (!metrics.is_good_progress()) { + _progress_last_gc.unset(); + cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); + op_degenerated_futile(); + } else { + _progress_last_gc.set(); + } +} + +void ShenandoahHeap::op_degenerated_fail() { + log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); + shenandoah_policy()->record_degenerated_upgrade_to_full(); + op_full(GCCause::_shenandoah_upgrade_to_full_gc); +} + +void ShenandoahHeap::op_degenerated_futile() { + shenandoah_policy()->record_degenerated_upgrade_to_full(); + op_full(GCCause::_shenandoah_upgrade_to_full_gc); +} + +void ShenandoahHeap::stop_concurrent_marking() { + assert(is_concurrent_mark_in_progress(), "How else could we get here?"); + set_concurrent_mark_in_progress(false); + if (!cancelled_gc()) { + // If we needed to update refs, and concurrent marking has been cancelled, + // we need to finish updating references. + set_has_forwarded_objects(false); + mark_complete_marking_context(); + } +} + +void ShenandoahHeap::force_satb_flush_all_threads() { + if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) { + // No need to flush SATBs + return; + } + + for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { + ShenandoahThreadLocalData::set_force_satb_flush(t, true); + } + // The threads are not "acquiring" their thread-local data, but it does not + // hurt to "release" the updates here anyway. + OrderAccess::fence(); +} + +void ShenandoahHeap::set_gc_state_all_threads(char state) { + for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { + ShenandoahThreadLocalData::set_gc_state(t, state); + } +} + +void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); + _gc_state.set_cond(mask, value); + set_gc_state_all_threads(_gc_state.raw_value()); +} + +void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { + if (has_forwarded_objects()) { + set_gc_state_mask(MARKING | UPDATEREFS, in_progress); + } else { + set_gc_state_mask(MARKING, in_progress); + } + ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); +} + +void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) { + set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress); + ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); +} + +void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); + set_gc_state_mask(EVACUATION, in_progress); +} + +void ShenandoahHeap::ref_processing_init() { + assert(_max_workers > 0, "Sanity"); + + _ref_processor = + new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery + ParallelRefProcEnabled, // MT processing + _max_workers, // Degree of MT processing + true, // MT discovery + _max_workers, // Degree of MT discovery + false, // Reference discovery is not atomic + NULL, // No closure, should be installed before use + true); // Scale worker threads + + shenandoah_assert_rp_isalive_not_installed(); +} + +GCTracer* ShenandoahHeap::tracer() { + return shenandoah_policy()->tracer(); +} + +size_t ShenandoahHeap::tlab_used(Thread* thread) const { + return _free_set->used(); +} + +void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { + if (try_cancel_gc()) { + FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); + log_info(gc)("%s", msg.buffer()); + Events::log(Thread::current(), "%s", msg.buffer()); + } +} + +uint ShenandoahHeap::max_workers() { + return _max_workers; +} + +void ShenandoahHeap::stop() { + // The shutdown sequence should be able to terminate when GC is running. + + // Step 0. Notify policy to disable event recording. + _shenandoah_policy->record_shutdown(); + + // Step 1. Notify control thread that we are in shutdown. + // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. + // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. + control_thread()->prepare_for_graceful_shutdown(); + + // Step 2. Notify GC workers that we are cancelling GC. + cancel_gc(GCCause::_shenandoah_stop_vm); + + // Step 3. Wait until GC worker exits normally. + control_thread()->stop(); + + // Step 4. Stop String Dedup thread if it is active + if (ShenandoahStringDedup::is_enabled()) { + ShenandoahStringDedup::stop(); + } +} + +void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) { + assert(heuristics()->can_unload_classes(), "Class unloading should be enabled"); + + ShenandoahGCPhase root_phase(full_gc ? + ShenandoahPhaseTimings::full_gc_purge : + ShenandoahPhaseTimings::purge); + + ShenandoahIsAliveSelector alive; + BoolObjectClosure* is_alive = alive.is_alive_closure(); + + bool purged_class; + + // Unload classes and purge SystemDictionary. + { + ShenandoahGCPhase phase(full_gc ? + ShenandoahPhaseTimings::full_gc_purge_class_unload : + ShenandoahPhaseTimings::purge_class_unload); + purged_class = SystemDictionary::do_unloading(gc_timer(), + full_gc /* do_cleaning*/ ); + } + + { + ShenandoahGCPhase phase(full_gc ? + ShenandoahPhaseTimings::full_gc_purge_par : + ShenandoahPhaseTimings::purge_par); + uint active = _workers->active_workers(); + ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class); + _workers->run_task(&unlink_task); + } + + if (ShenandoahStringDedup::is_enabled()) { + ShenandoahGCPhase phase(full_gc ? + ShenandoahPhaseTimings::full_gc_purge_string_dedup : + ShenandoahPhaseTimings::purge_string_dedup); + ShenandoahStringDedup::parallel_cleanup(); + } + + { + ShenandoahGCPhase phase(full_gc ? + ShenandoahPhaseTimings::full_gc_purge_cldg : + ShenandoahPhaseTimings::purge_cldg); + ClassLoaderDataGraph::purge(); + } +} + +void ShenandoahHeap::set_has_forwarded_objects(bool cond) { + set_gc_state_mask(HAS_FORWARDED, cond); +} + +void ShenandoahHeap::set_process_references(bool pr) { + _process_references.set_cond(pr); +} + +void ShenandoahHeap::set_unload_classes(bool uc) { + _unload_classes.set_cond(uc); +} + +bool ShenandoahHeap::process_references() const { + return _process_references.is_set(); +} + +bool ShenandoahHeap::unload_classes() const { + return _unload_classes.is_set(); +} + +address ShenandoahHeap::in_cset_fast_test_addr() { + ShenandoahHeap* heap = ShenandoahHeap::heap(); + assert(heap->collection_set() != NULL, "Sanity"); + return (address) heap->collection_set()->biased_map_address(); +} + +address ShenandoahHeap::cancelled_gc_addr() { + return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); +} + +address ShenandoahHeap::gc_state_addr() { + return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); +} + +size_t ShenandoahHeap::bytes_allocated_since_gc_start() { + return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start); +} + +void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { + OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); +} + +void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { + _degenerated_gc_in_progress.set_cond(in_progress); +} + +void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { + _full_gc_in_progress.set_cond(in_progress); +} + +void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { + assert (is_full_gc_in_progress(), "should be"); + _full_gc_move_in_progress.set_cond(in_progress); +} + +void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { + set_gc_state_mask(UPDATEREFS, in_progress); +} + +void ShenandoahHeap::register_nmethod(nmethod* nm) { + ShenandoahCodeRoots::add_nmethod(nm); +} + +void ShenandoahHeap::unregister_nmethod(nmethod* nm) { + ShenandoahCodeRoots::remove_nmethod(nm); +} + +oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { + heap_region_containing(o)->record_pin(); + return o; +} + +void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { + heap_region_containing(o)->record_unpin(); +} + +void ShenandoahHeap::sync_pinned_region_status() { + ShenandoahHeapLocker locker(lock()); + + for (size_t i = 0; i < num_regions(); i++) { + ShenandoahHeapRegion *r = get_region(i); + if (r->is_active()) { + if (r->is_pinned()) { + if (r->pin_count() == 0) { + r->make_unpinned(); + } + } else { + if (r->pin_count() > 0) { + r->make_pinned(); + } + } + } + } + + assert_pinned_region_status(); +} + +#ifdef ASSERT +void ShenandoahHeap::assert_pinned_region_status() { + for (size_t i = 0; i < num_regions(); i++) { + ShenandoahHeapRegion* r = get_region(i); + assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), + "Region " SIZE_FORMAT " pinning status is inconsistent", i); + } +} +#endif + +GCTimer* ShenandoahHeap::gc_timer() const { + return _gc_timer; +} + +#ifdef ASSERT +void ShenandoahHeap::assert_gc_workers(uint nworkers) { + assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); + + if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { + if (UseDynamicNumberOfGCThreads || + (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { + assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); + } else { + // Use ParallelGCThreads inside safepoints + assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); + } + } else { + if (UseDynamicNumberOfGCThreads || + (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { + assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); + } else { + // Use ConcGCThreads outside safepoints + assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); + } + } +} +#endif + +ShenandoahVerifier* ShenandoahHeap::verifier() { + guarantee(ShenandoahVerify, "Should be enabled"); + assert (_verifier != NULL, "sanity"); + return _verifier; +} + +template +class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { +private: + T cl; + ShenandoahHeap* _heap; + ShenandoahRegionIterator* _regions; + bool _concurrent; +public: + ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : + AbstractGangTask("Concurrent Update References Task"), + cl(T()), + _heap(ShenandoahHeap::heap()), + _regions(regions), + _concurrent(concurrent) { + } + + void work(uint worker_id) { + if (_concurrent) { + ShenandoahConcurrentWorkerSession worker_session(worker_id); + ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); + do_work(); + } else { + ShenandoahParallelWorkerSession worker_session(worker_id); + do_work(); + } + } + +private: + void do_work() { + ShenandoahHeapRegion* r = _regions->next(); + ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); + while (r != NULL) { + HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); + assert (top_at_start_ur >= r->bottom(), "sanity"); + if (r->is_active() && !r->is_cset()) { + _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); + } + if (ShenandoahPacing) { + _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); + } + if (_heap->check_cancelled_gc_and_yield(_concurrent)) { + return; + } + r = _regions->next(); + } + } +}; + +void ShenandoahHeap::update_heap_references(bool concurrent) { + ShenandoahUpdateHeapRefsTask task(&_update_refs_iterator, concurrent); + workers()->run_task(&task); +} + +void ShenandoahHeap::op_init_updaterefs() { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); + + set_evacuation_in_progress(false); + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs); + retire_and_reset_gclabs(); + } + + if (ShenandoahVerify) { + if (!is_degenerated_gc_in_progress()) { + verifier()->verify_roots_no_forwarded_except(ShenandoahRootVerifier::ThreadRoots); + } + verifier()->verify_before_updaterefs(); + } + + set_update_refs_in_progress(true); + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare); + + make_parsable(true); + for (uint i = 0; i < num_regions(); i++) { + ShenandoahHeapRegion* r = get_region(i); + r->set_concurrent_iteration_safe_limit(r->top()); + } + + // Reset iterator. + _update_refs_iterator.reset(); + } + + if (ShenandoahPacing) { + pacer()->setup_for_updaterefs(); + } +} + +void ShenandoahHeap::op_final_updaterefs() { + assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); + + // Check if there is left-over work, and finish it + if (_update_refs_iterator.has_next()) { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work); + + // Finish updating references where we left off. + clear_cancelled_gc(); + update_heap_references(false); + } + + // Clear cancelled GC, if set. On cancellation path, the block before would handle + // everything. On degenerated paths, cancelled gc would not be set anyway. + if (cancelled_gc()) { + clear_cancelled_gc(); + } + assert(!cancelled_gc(), "Should have been done right before"); + + if (ShenandoahVerify && !is_degenerated_gc_in_progress()) { + verifier()->verify_roots_no_forwarded_except(ShenandoahRootVerifier::ThreadRoots); + } + + if (is_degenerated_gc_in_progress()) { + concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); + } else { + concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots); + } + + // Has to be done before cset is clear + if (ShenandoahVerify) { + verifier()->verify_roots_in_to_space(); + } + + // Drop unnecessary "pinned" state from regions that does not have CP marks + // anymore, as this would allow trashing them below. + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned); + sync_pinned_region_status(); + } + + { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset); + trash_cset_regions(); + } + + set_has_forwarded_objects(false); + set_update_refs_in_progress(false); + + if (ShenandoahVerify) { + verifier()->verify_after_updaterefs(); + } + + if (VerifyAfterGC) { + Universe::verify(); + } + + { + ShenandoahHeapLocker locker(lock()); + _free_set->rebuild(); + } +} + +#ifdef ASSERT +void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { + _lock.assert_owned_by_current_thread(); +} + +void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { + _lock.assert_not_owned_by_current_thread(); +} + +void ShenandoahHeap::assert_heaplock_or_safepoint() { + _lock.assert_owned_by_current_thread_or_safepoint(); +} +#endif + +void ShenandoahHeap::print_extended_on(outputStream *st) const { + print_on(st); + print_heap_regions_on(st); +} + +bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { + size_t slice = r->region_number() / _bitmap_regions_per_slice; + + size_t regions_from = _bitmap_regions_per_slice * slice; + size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); + for (size_t g = regions_from; g < regions_to; g++) { + assert (g / _bitmap_regions_per_slice == slice, "same slice"); + if (skip_self && g == r->region_number()) continue; + if (get_region(g)->is_committed()) { + return true; + } + } + return false; +} + +bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { + assert_heaplock_owned_by_current_thread(); + + // Bitmaps in special regions do not need commits + if (_bitmap_region_special) { + return true; + } + + if (is_bitmap_slice_committed(r, true)) { + // Some other region from the group is already committed, meaning the bitmap + // slice is already committed, we exit right away. + return true; + } + + // Commit the bitmap slice: + size_t slice = r->region_number() / _bitmap_regions_per_slice; + size_t off = _bitmap_bytes_per_slice * slice; + size_t len = _bitmap_bytes_per_slice; + if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { + return false; + } + return true; +} + +bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { + assert_heaplock_owned_by_current_thread(); + + // Bitmaps in special regions do not need uncommits + if (_bitmap_region_special) { + return true; + } + + if (is_bitmap_slice_committed(r, true)) { + // Some other region from the group is still committed, meaning the bitmap + // slice is should stay committed, exit right away. + return true; + } + + // Uncommit the bitmap slice: + size_t slice = r->region_number() / _bitmap_regions_per_slice; + size_t off = _bitmap_bytes_per_slice * slice; + size_t len = _bitmap_bytes_per_slice; + if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { + return false; + } + return true; +} + +void ShenandoahHeap::safepoint_synchronize_begin() { + if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { + SuspendibleThreadSet::synchronize(); + } +} + +void ShenandoahHeap::safepoint_synchronize_end() { + if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { + SuspendibleThreadSet::desynchronize(); + } +} + +void ShenandoahHeap::vmop_entry_init_mark() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); + + try_inject_alloc_failure(); + VM_ShenandoahInitMark op; + VMThread::execute(&op); // jump to entry_init_mark() under safepoint +} + +void ShenandoahHeap::vmop_entry_final_mark() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); + + try_inject_alloc_failure(); + VM_ShenandoahFinalMarkStartEvac op; + VMThread::execute(&op); // jump to entry_final_mark under safepoint +} + +void ShenandoahHeap::vmop_entry_final_evac() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); + + VM_ShenandoahFinalEvac op; + VMThread::execute(&op); // jump to entry_final_evac under safepoint +} + +void ShenandoahHeap::vmop_entry_init_updaterefs() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); + + try_inject_alloc_failure(); + VM_ShenandoahInitUpdateRefs op; + VMThread::execute(&op); +} + +void ShenandoahHeap::vmop_entry_final_updaterefs() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); + + try_inject_alloc_failure(); + VM_ShenandoahFinalUpdateRefs op; + VMThread::execute(&op); +} + +void ShenandoahHeap::vmop_entry_init_traversal() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross); + + try_inject_alloc_failure(); + VM_ShenandoahInitTraversalGC op; + VMThread::execute(&op); +} + +void ShenandoahHeap::vmop_entry_final_traversal() { + TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross); + + try_inject_alloc_failure(); + VM_ShenandoahFinalTraversalGC op; + VMThread::execute(&op); +} + +void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { + TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); + + try_inject_alloc_failure(); + VM_ShenandoahFullGC op(cause); + VMThread::execute(&op); +} + +void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { + TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); + ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); + + VM_ShenandoahDegeneratedGC degenerated_gc((int)point); + VMThread::execute(°enerated_gc); +} + +void ShenandoahHeap::entry_init_mark() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); + const char* msg = init_mark_event_message(); + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_init_marking(), + "init marking"); + + op_init_mark(); +} + +void ShenandoahHeap::entry_final_mark() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); + const char* msg = final_mark_event_message(); + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_final_marking(), + "final marking"); + + op_final_mark(); +} + +void ShenandoahHeap::entry_final_evac() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); + static const char* msg = "Pause Final Evac"; + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + op_final_evac(); +} + +void ShenandoahHeap::entry_init_updaterefs() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); + + static const char* msg = "Pause Init Update Refs"; + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + // No workers used in this phase, no setup required + + op_init_updaterefs(); +} + +void ShenandoahHeap::entry_final_updaterefs() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); + + static const char* msg = "Pause Final Update Refs"; + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), + "final reference update"); + + op_final_updaterefs(); +} + +void ShenandoahHeap::entry_init_traversal() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc); + + static const char* msg = "Pause Init Traversal"; + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), + "init traversal"); + + op_init_traversal(); +} + +void ShenandoahHeap::entry_final_traversal() { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc); + + static const char* msg = "Pause Final Traversal"; + GCTraceTime(Info, gc) time(msg, gc_timer()); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), + "final traversal"); + + op_final_traversal(); +} + +void ShenandoahHeap::entry_full(GCCause::Cause cause) { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); + + static const char* msg = "Pause Full"; + GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_fullgc(), + "full gc"); + + op_full(cause); +} + +void ShenandoahHeap::entry_degenerated(int point) { + ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); + ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); + + ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; + const char* msg = degen_event_message(dpoint); + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), + "stw degenerated gc"); + + set_degenerated_gc_in_progress(true); + op_degenerated(dpoint); + set_degenerated_gc_in_progress(false); +} + +void ShenandoahHeap::entry_mark() { + TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); + + const char* msg = conc_mark_event_message(); + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), + "concurrent marking"); + + try_inject_alloc_failure(); + op_mark(); +} + +void ShenandoahHeap::entry_evac() { + ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); + TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); + + static const char* msg = "Concurrent evacuation"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), + "concurrent evacuation"); + + try_inject_alloc_failure(); + op_conc_evac(); +} + +void ShenandoahHeap::entry_updaterefs() { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); + + static const char* msg = "Concurrent update references"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), + "concurrent reference update"); + + try_inject_alloc_failure(); + op_updaterefs(); +} +void ShenandoahHeap::entry_cleanup() { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); + + static const char* msg = "Concurrent cleanup"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + // This phase does not use workers, no need for setup + + try_inject_alloc_failure(); + op_cleanup(); +} + +void ShenandoahHeap::entry_reset() { + ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); + + static const char* msg = "Concurrent reset"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), + "concurrent reset"); + + try_inject_alloc_failure(); + op_reset(); +} + +void ShenandoahHeap::entry_preclean() { + if (ShenandoahPreclean && process_references()) { + static const char* msg = "Concurrent precleaning"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), + "concurrent preclean", + /* check_workers = */ false); + + try_inject_alloc_failure(); + op_preclean(); + } +} + +void ShenandoahHeap::entry_traversal() { + static const char* msg = "Concurrent traversal"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); + + ShenandoahWorkerScope scope(workers(), + ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(), + "concurrent traversal"); + + try_inject_alloc_failure(); + op_traversal(); +} + +void ShenandoahHeap::entry_uncommit(double shrink_before) { + static const char *msg = "Concurrent uncommit"; + GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); + EventMark em("%s", msg); + + ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); + + op_uncommit(shrink_before); +} + +void ShenandoahHeap::try_inject_alloc_failure() { + if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { + _inject_alloc_failure.set(); + os::naked_short_sleep(1); + if (cancelled_gc()) { + log_info(gc)("Allocation failure was successfully injected"); + } + } +} + +bool ShenandoahHeap::should_inject_alloc_failure() { + return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); +} + +void ShenandoahHeap::initialize_serviceability() { + _memory_pool = new ShenandoahMemoryPool(this); + _cycle_memory_manager.add_pool(_memory_pool); + _stw_memory_manager.add_pool(_memory_pool); +} + +GrowableArray ShenandoahHeap::memory_managers() { + GrowableArray memory_managers(2); + memory_managers.append(&_cycle_memory_manager); + memory_managers.append(&_stw_memory_manager); + return memory_managers; +} + +GrowableArray ShenandoahHeap::memory_pools() { + GrowableArray memory_pools(1); + memory_pools.append(_memory_pool); + return memory_pools; +} + +MemoryUsage ShenandoahHeap::memory_usage() { + return _memory_pool->get_memory_usage(); +} + +void ShenandoahHeap::enter_evacuation() { + _oom_evac_handler.enter_evacuation(); +} + +void ShenandoahHeap::leave_evacuation() { + _oom_evac_handler.leave_evacuation(); +} + +ShenandoahRegionIterator::ShenandoahRegionIterator() : + _heap(ShenandoahHeap::heap()), + _index(0) {} + +ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : + _heap(heap), + _index(0) {} + +void ShenandoahRegionIterator::reset() { + _index = 0; +} + +bool ShenandoahRegionIterator::has_next() const { + return _index < _heap->num_regions(); +} + +char ShenandoahHeap::gc_state() const { + return _gc_state.raw_value(); +} + +void ShenandoahHeap::deduplicate_string(oop str) { + assert(java_lang_String::is_instance(str), "invariant"); + + if (ShenandoahStringDedup::is_enabled()) { + ShenandoahStringDedup::deduplicate(str); + } +} + +const char* ShenandoahHeap::init_mark_event_message() const { + bool update_refs = has_forwarded_objects(); + bool proc_refs = process_references(); + bool unload_cls = unload_classes(); + + if (update_refs && proc_refs && unload_cls) { + return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; + } else if (update_refs && proc_refs) { + return "Pause Init Mark (update refs) (process weakrefs)"; + } else if (update_refs && unload_cls) { + return "Pause Init Mark (update refs) (unload classes)"; + } else if (proc_refs && unload_cls) { + return "Pause Init Mark (process weakrefs) (unload classes)"; + } else if (update_refs) { + return "Pause Init Mark (update refs)"; + } else if (proc_refs) { + return "Pause Init Mark (process weakrefs)"; + } else if (unload_cls) { + return "Pause Init Mark (unload classes)"; + } else { + return "Pause Init Mark"; + } +} + +const char* ShenandoahHeap::final_mark_event_message() const { + bool update_refs = has_forwarded_objects(); + bool proc_refs = process_references(); + bool unload_cls = unload_classes(); + + if (update_refs && proc_refs && unload_cls) { + return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; + } else if (update_refs && proc_refs) { + return "Pause Final Mark (update refs) (process weakrefs)"; + } else if (update_refs && unload_cls) { + return "Pause Final Mark (update refs) (unload classes)"; + } else if (proc_refs && unload_cls) { + return "Pause Final Mark (process weakrefs) (unload classes)"; + } else if (update_refs) { + return "Pause Final Mark (update refs)"; + } else if (proc_refs) { + return "Pause Final Mark (process weakrefs)"; + } else if (unload_cls) { + return "Pause Final Mark (unload classes)"; + } else { + return "Pause Final Mark"; + } +} + +const char* ShenandoahHeap::conc_mark_event_message() const { + bool update_refs = has_forwarded_objects(); + bool proc_refs = process_references(); + bool unload_cls = unload_classes(); + + if (update_refs && proc_refs && unload_cls) { + return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; + } else if (update_refs && proc_refs) { + return "Concurrent marking (update refs) (process weakrefs)"; + } else if (update_refs && unload_cls) { + return "Concurrent marking (update refs) (unload classes)"; + } else if (proc_refs && unload_cls) { + return "Concurrent marking (process weakrefs) (unload classes)"; + } else if (update_refs) { + return "Concurrent marking (update refs)"; + } else if (proc_refs) { + return "Concurrent marking (process weakrefs)"; + } else if (unload_cls) { + return "Concurrent marking (unload classes)"; + } else { + return "Concurrent marking"; + } +} + +const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { + switch (point) { + case _degenerated_unset: + return "Pause Degenerated GC ()"; + case _degenerated_traversal: + return "Pause Degenerated GC (Traversal)"; + case _degenerated_outside_cycle: + return "Pause Degenerated GC (Outside of Cycle)"; + case _degenerated_mark: + return "Pause Degenerated GC (Mark)"; + case _degenerated_evac: + return "Pause Degenerated GC (Evacuation)"; + case _degenerated_updaterefs: + return "Pause Degenerated GC (Update Refs)"; + default: + ShouldNotReachHere(); + return "ERROR"; + } +} + +jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { +#ifdef ASSERT + assert(_liveness_cache != NULL, "sanity"); + assert(worker_id < _max_workers, "sanity"); + for (uint i = 0; i < num_regions(); i++) { + assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); + } +#endif + return _liveness_cache[worker_id]; +} + +void ShenandoahHeap::flush_liveness_cache(uint worker_id) { + assert(worker_id < _max_workers, "sanity"); + assert(_liveness_cache != NULL, "sanity"); + jushort* ld = _liveness_cache[worker_id]; + for (uint i = 0; i < num_regions(); i++) { + ShenandoahHeapRegion* r = get_region(i); + jushort live = ld[i]; + if (live > 0) { + r->increase_live_data_gc_words(live); + ld[i] = 0; + } + } +}