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/*
* Copyright (c) 2023, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013, 2022, Red Hat, Inc. All rights reserved.
+ * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
#include "gc/shared/locationPrinter.inline.hpp"
#include "gc/shared/memAllocator.hpp"
#include "gc/shared/plab.hpp"
#include "gc/shared/tlab_globals.hpp"
+ #include "gc/shenandoah/shenandoahAgeCensus.hpp"
+ #include "gc/shenandoah/heuristics/shenandoahOldHeuristics.hpp"
+ #include "gc/shenandoah/heuristics/shenandoahYoungHeuristics.hpp"
+ #include "gc/shenandoah/shenandoahAllocRequest.hpp"
#include "gc/shenandoah/shenandoahBarrierSet.hpp"
+ #include "gc/shenandoah/shenandoahCardTable.hpp"
#include "gc/shenandoah/shenandoahClosures.inline.hpp"
#include "gc/shenandoah/shenandoahCollectionSet.hpp"
#include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
#include "gc/shenandoah/shenandoahConcurrentMark.hpp"
#include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
#include "gc/shenandoah/shenandoahControlThread.hpp"
#include "gc/shenandoah/shenandoahFreeSet.hpp"
+ #include "gc/shenandoah/shenandoahGenerationalEvacuationTask.hpp"
+ #include "gc/shenandoah/shenandoahGenerationalHeap.hpp"
+ #include "gc/shenandoah/shenandoahGlobalGeneration.hpp"
#include "gc/shenandoah/shenandoahPhaseTimings.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
#include "gc/shenandoah/shenandoahInitLogger.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/shenandoahOldGeneration.hpp"
#include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
#include "gc/shenandoah/shenandoahPacer.inline.hpp"
#include "gc/shenandoah/shenandoahPadding.hpp"
#include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp"
#include "gc/shenandoah/shenandoahReferenceProcessor.hpp"
#include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
+ #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
#include "gc/shenandoah/shenandoahSTWMark.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"
+ #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
+ #include "gc/shenandoah/mode/shenandoahGenerationalMode.hpp"
#include "gc/shenandoah/mode/shenandoahIUMode.hpp"
#include "gc/shenandoah/mode/shenandoahPassiveMode.hpp"
#include "gc/shenandoah/mode/shenandoahSATBMode.hpp"
+ #include "utilities/globalDefinitions.hpp"
+
#if INCLUDE_JFR
#include "gc/shenandoah/shenandoahJfrSupport.hpp"
#endif
#include "classfile/systemDictionary.hpp"
_num_regions = ShenandoahHeapRegion::region_count();
assert(_num_regions == (max_byte_size / reg_size_bytes),
"Regions should cover entire heap exactly: " SIZE_FORMAT " != " SIZE_FORMAT "/" SIZE_FORMAT,
_num_regions, max_byte_size, reg_size_bytes);
- // Now we know the number of regions, initialize the heuristics.
- initialize_heuristics();
-
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;
// Default to max heap size.
_soft_max_size = _num_regions * reg_size_bytes;
_committed = _initial_size;
+ // Now we know the number of regions and heap sizes, initialize the heuristics.
+ initialize_heuristics_generations();
+
size_t heap_page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
size_t bitmap_page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
size_t region_page_size = UseLargePages ? os::large_page_size() : os::vm_page_size();
//
if (!_heap_region_special) {
os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
"Cannot commit heap memory");
}
+ BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this, _heap_region));
+
+ //
+ // After reserving the Java heap, create the card table, barriers, and workers, in dependency order
+ //
+ if (mode()->is_generational()) {
+ ShenandoahDirectCardMarkRememberedSet *rs;
+ ShenandoahCardTable* card_table = ShenandoahBarrierSet::barrier_set()->card_table();
+ size_t card_count = card_table->cards_required(heap_rs.size() / HeapWordSize);
+ rs = new ShenandoahDirectCardMarkRememberedSet(ShenandoahBarrierSet::barrier_set()->card_table(), card_count);
+ _card_scan = new ShenandoahScanRemembered<ShenandoahDirectCardMarkRememberedSet>(rs);
+
+ // Age census structure
+ _age_census = new ShenandoahAgeCensus();
+ }
+
+ _workers = new ShenandoahWorkerThreads("Shenandoah GC Threads", _max_workers);
+ if (_workers == nullptr) {
+ vm_exit_during_initialization("Failed necessary allocation.");
+ } else {
+ _workers->initialize_workers();
+ }
+
+ if (ParallelGCThreads > 1) {
+ _safepoint_workers = new ShenandoahWorkerThreads("Safepoint Cleanup Thread", ParallelGCThreads);
+ _safepoint_workers->initialize_workers();
+ }
+
//
// Reserve and commit memory for bitmap(s)
//
size_t bitmap_size_orig = ShenandoahMarkBitMap::compute_size(heap_rs.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, _max_workers);
if (ShenandoahVerify) {
ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
os::trace_page_sizes_for_requested_size("Verify Bitmap",
bitmap_size_orig, 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);
os::trace_page_sizes_for_requested_size("Verify Bitmap",
bitmap_size_orig, bitmap_page_size,
cset_rs.base(),
cset_rs.size(), cset_rs.page_size());
}
_regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
+ _affiliations = NEW_C_HEAP_ARRAY(uint8_t, _num_regions, mtGC);
_free_set = new ShenandoahFreeSet(this, _num_regions);
{
ShenandoahHeapLocker locker(lock());
+
for (size_t i = 0; i < _num_regions; i++) {
HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i;
bool is_committed = i < num_committed_regions;
void* loc = region_storage.base() + i * region_align;
assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity");
_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 (AlwaysPreTouch) {
// 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,
assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity");
_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");
+
+ _affiliations[i] = ShenandoahAffiliation::FREE;
}
// Initialize to complete
_marking_context->mark_complete();
+ size_t young_cset_regions, old_cset_regions;
! // We are initializing free set. We ignore cset region tallies.
+ size_t first_old, last_old, num_old;
+ _free_set->prepare_to_rebuild(young_cset_regions, old_cset_regions, first_old, last_old, num_old);
+ _free_set->rebuild(young_cset_regions, old_cset_regions);
}
if (AlwaysPreTouch) {
// 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,
if (ShenandoahPacing) {
_pacer = new ShenandoahPacer(this);
_pacer->setup_for_idle();
}
! _control_thread = new ShenandoahControlThread();
! ShenandoahInitLogger::print();
return JNI_OK;
}
! void ShenandoahHeap::initialize_mode() {
if (ShenandoahGCMode != nullptr) {
if (strcmp(ShenandoahGCMode, "satb") == 0) {
_gc_mode = new ShenandoahSATBMode();
} else if (strcmp(ShenandoahGCMode, "iu") == 0) {
_gc_mode = new ShenandoahIUMode();
} else if (strcmp(ShenandoahGCMode, "passive") == 0) {
_gc_mode = new ShenandoahPassiveMode();
} else {
vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
}
} else {
vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option (null)");
if (ShenandoahPacing) {
_pacer = new ShenandoahPacer(this);
_pacer->setup_for_idle();
}
! initialize_controller();
! print_init_logger();
return JNI_OK;
}
! void ShenandoahHeap::initialize_controller() {
+ _control_thread = new ShenandoahControlThread();
+ }
+
+ void ShenandoahHeap::print_init_logger() const {
+ ShenandoahInitLogger::print();
+ }
+
+ void ShenandoahHeap::initialize_heuristics_generations() {
if (ShenandoahGCMode != nullptr) {
if (strcmp(ShenandoahGCMode, "satb") == 0) {
_gc_mode = new ShenandoahSATBMode();
} else if (strcmp(ShenandoahGCMode, "iu") == 0) {
_gc_mode = new ShenandoahIUMode();
} else if (strcmp(ShenandoahGCMode, "passive") == 0) {
_gc_mode = new ShenandoahPassiveMode();
+ } else if (strcmp(ShenandoahGCMode, "generational") == 0) {
+ _gc_mode = new ShenandoahGenerationalMode();
} else {
vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
}
} else {
vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option (null)");
if (_gc_mode->is_experimental() && !UnlockExperimentalVMOptions) {
vm_exit_during_initialization(
err_msg("GC mode \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
_gc_mode->name()));
}
- }
! void ShenandoahHeap::initialize_heuristics() {
! assert(_gc_mode != nullptr, "Must be initialized");
! _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()));
}
}
#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(nullptr),
_safepoint_workers(nullptr),
_heap_region_special(false),
_num_regions(0),
_regions(nullptr),
_update_refs_iterator(this),
_gc_state_changed(false),
_gc_no_progress_count(0),
_control_thread(nullptr),
_shenandoah_policy(policy),
- _gc_mode(nullptr),
- _heuristics(nullptr),
_free_set(nullptr),
_pacer(nullptr),
_verifier(nullptr),
_phase_timings(nullptr),
_monitoring_support(nullptr),
_memory_pool(nullptr),
_stw_memory_manager("Shenandoah Pauses"),
_cycle_memory_manager("Shenandoah Cycles"),
_gc_timer(new ConcurrentGCTimer()),
_log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
- _ref_processor(new ShenandoahReferenceProcessor(MAX2(_max_workers, 1U))),
_marking_context(nullptr),
_bitmap_size(0),
_bitmap_regions_per_slice(0),
_bitmap_bytes_per_slice(0),
_bitmap_region_special(false),
_aux_bitmap_region_special(false),
_liveness_cache(nullptr),
! _collection_set(nullptr)
{
- // Initialize GC mode early, so we can adjust barrier support
- initialize_mode();
- BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
-
- _max_workers = MAX2(_max_workers, 1U);
- _workers = new ShenandoahWorkerThreads("Shenandoah GC Threads", _max_workers);
- if (_workers == nullptr) {
- vm_exit_during_initialization("Failed necessary allocation.");
- } else {
- _workers->initialize_workers();
- }
-
- if (ParallelGCThreads > 1) {
- _safepoint_workers = new ShenandoahWorkerThreads("Safepoint Cleanup Thread",
- ParallelGCThreads);
- _safepoint_workers->initialize_workers();
- }
}
#ifdef _MSC_VER
#pragma warning( pop )
#endif
- class ShenandoahResetBitmapTask : public WorkerTask {
- private:
- ShenandoahRegionIterator _regions;
-
- public:
- ShenandoahResetBitmapTask() :
- WorkerTask("Shenandoah Reset Bitmap") {}
-
- void work(uint worker_id) {
- ShenandoahHeapRegion* region = _regions.next();
- ShenandoahHeap* heap = ShenandoahHeap::heap();
- ShenandoahMarkingContext* const ctx = heap->marking_context();
- while (region != nullptr) {
- 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 max, " SIZE_FORMAT "%s soft max, " 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(soft_max_capacity()), proper_unit_for_byte_size(soft_max_capacity()),
if (_gc_mode->is_experimental() && !UnlockExperimentalVMOptions) {
vm_exit_during_initialization(
err_msg("GC mode \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
_gc_mode->name()));
}
! // Max capacity is the maximum _allowed_ capacity. That is, the maximum allowed capacity
! // for old would be total heap - minimum capacity of young. This means the sum of the maximum
! // allowed for old and young could exceed the total heap size. It remains the case that the
+ // _actual_ capacity of young + old = total.
+ _generation_sizer.heap_size_changed(max_capacity());
+ size_t initial_capacity_young = _generation_sizer.max_young_size();
+ size_t max_capacity_young = _generation_sizer.max_young_size();
+ size_t initial_capacity_old = max_capacity() - max_capacity_young;
+ size_t max_capacity_old = max_capacity() - initial_capacity_young;
! _young_generation = new ShenandoahYoungGeneration(_max_workers, max_capacity_young, initial_capacity_young);
! _old_generation = new ShenandoahOldGeneration(_max_workers, max_capacity_old, initial_capacity_old);
! _global_generation = new ShenandoahGlobalGeneration(_gc_mode->is_generational(), _max_workers, max_capacity(), max_capacity());
! _global_generation->initialize_heuristics(_gc_mode);
! if (mode()->is_generational()) {
! _young_generation->initialize_heuristics(_gc_mode);
! _old_generation->initialize_heuristics(_gc_mode);
}
+ _evac_tracker = new ShenandoahEvacuationTracker(mode()->is_generational());
}
#ifdef _MSC_VER
#pragma warning( push )
#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
#endif
ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
CollectedHeap(),
+ _gc_generation(nullptr),
_initial_size(0),
_committed(0),
! _max_workers(MAX3(ConcGCThreads, ParallelGCThreads, 1U)),
_workers(nullptr),
_safepoint_workers(nullptr),
_heap_region_special(false),
_num_regions(0),
_regions(nullptr),
+ _affiliations(nullptr),
_update_refs_iterator(this),
_gc_state_changed(false),
_gc_no_progress_count(0),
+ _age_census(nullptr),
+ _cancel_requested_time(0),
+ _young_generation(nullptr),
+ _global_generation(nullptr),
+ _old_generation(nullptr),
_control_thread(nullptr),
_shenandoah_policy(policy),
_free_set(nullptr),
_pacer(nullptr),
_verifier(nullptr),
_phase_timings(nullptr),
+ _evac_tracker(nullptr),
+ _mmu_tracker(),
+ _generation_sizer(),
_monitoring_support(nullptr),
_memory_pool(nullptr),
_stw_memory_manager("Shenandoah Pauses"),
_cycle_memory_manager("Shenandoah Cycles"),
_gc_timer(new ConcurrentGCTimer()),
_log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
_marking_context(nullptr),
_bitmap_size(0),
_bitmap_regions_per_slice(0),
_bitmap_bytes_per_slice(0),
_bitmap_region_special(false),
_aux_bitmap_region_special(false),
_liveness_cache(nullptr),
! _collection_set(nullptr),
+ _card_scan(nullptr)
{
}
#ifdef _MSC_VER
#pragma warning( pop )
#endif
void ShenandoahHeap::print_on(outputStream* st) const {
st->print_cr("Shenandoah Heap");
st->print_cr(" " SIZE_FORMAT "%s max, " SIZE_FORMAT "%s soft max, " 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(soft_max_capacity()), proper_unit_for_byte_size(soft_max_capacity()),
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_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, ");
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_old_mark_in_progress()) st->print("old marking, ");
+ if (is_concurrent_young_mark_in_progress()) st->print("young marking, ");
if (is_evacuation_in_progress()) st->print("evacuating, ");
if (is_update_refs_in_progress()) st->print("updating refs, ");
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, ");
}
};
void ShenandoahHeap::post_initialize() {
CollectedHeap::post_initialize();
+ _mmu_tracker.initialize();
+
MutexLocker ml(Threads_lock);
ShenandoahInitWorkerGCLABClosure init_gclabs;
_workers->threads_do(&init_gclabs);
if (_safepoint_workers != nullptr) {
_safepoint_workers->threads_do(&init_gclabs);
_safepoint_workers->set_initialize_gclab();
}
- _heuristics->initialize();
-
JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers();)
}
size_t ShenandoahHeap::used() const {
! return Atomic::load(&_used);
}
size_t ShenandoahHeap::committed() const {
return Atomic::load(&_committed);
}
- size_t ShenandoahHeap::available() const {
- return free_set()->available();
- }
-
void ShenandoahHeap::increase_committed(size_t bytes) {
shenandoah_assert_heaplocked_or_safepoint();
_committed += bytes;
}
void ShenandoahHeap::decrease_committed(size_t bytes) {
shenandoah_assert_heaplocked_or_safepoint();
_committed -= bytes;
}
! void ShenandoahHeap::increase_used(size_t bytes) {
! Atomic::add(&_used, bytes, memory_order_relaxed);
}
! void ShenandoahHeap::set_used(size_t bytes) {
! Atomic::store(&_used, bytes);
}
! void ShenandoahHeap::decrease_used(size_t bytes) {
! assert(used() >= bytes, "never decrease heap size by more than we've left");
! Atomic::sub(&_used, bytes, memory_order_relaxed);
}
! void ShenandoahHeap::increase_allocated(size_t bytes) {
! Atomic::add(&_bytes_allocated_since_gc_start, bytes, memory_order_relaxed);
}
! 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 {
if (_safepoint_workers != nullptr) {
_safepoint_workers->threads_do(&init_gclabs);
_safepoint_workers->set_initialize_gclab();
}
JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers();)
}
+ ShenandoahHeuristics* ShenandoahHeap::heuristics() {
+ return _global_generation->heuristics();
+ }
+
size_t ShenandoahHeap::used() const {
! return global_generation()->used();
}
size_t ShenandoahHeap::committed() const {
return Atomic::load(&_committed);
}
void ShenandoahHeap::increase_committed(size_t bytes) {
shenandoah_assert_heaplocked_or_safepoint();
_committed += bytes;
}
void ShenandoahHeap::decrease_committed(size_t bytes) {
shenandoah_assert_heaplocked_or_safepoint();
_committed -= bytes;
}
! // For tracking usage based on allocations, it should be the case that:
! // * The sum of regions::used == heap::used
+ // * The sum of a generation's regions::used == generation::used
+ // * The sum of a generation's humongous regions::free == generation::humongous_waste
+ // These invariants are checked by the verifier on GC safepoints.
+ //
+ // Additional notes:
+ // * When a mutator's allocation request causes a region to be retired, the
+ // free memory left in that region is considered waste. It does not contribute
+ // to the usage, but it _does_ contribute to allocation rate.
+ // * The bottom of a PLAB must be aligned on card size. In some cases this will
+ // require padding in front of the PLAB (a filler object). Because this padding
+ // is included in the region's used memory we include the padding in the usage
+ // accounting as waste.
+ // * Mutator allocations are used to compute an allocation rate. They are also
+ // sent to the Pacer for those purposes.
+ // * There are three sources of waste:
+ // 1. The padding used to align a PLAB on card size
+ // 2. Region's free is less than minimum TLAB size and is retired
+ // 3. The unused portion of memory in the last region of a humongous object
+ void ShenandoahHeap::increase_used(const ShenandoahAllocRequest& req) {
+ size_t actual_bytes = req.actual_size() * HeapWordSize;
+ size_t wasted_bytes = req.waste() * HeapWordSize;
+ ShenandoahGeneration* generation = generation_for(req.affiliation());
+
+ if (req.is_gc_alloc()) {
+ assert(wasted_bytes == 0 || req.type() == ShenandoahAllocRequest::_alloc_plab, "Only PLABs have waste");
+ increase_used(generation, actual_bytes + wasted_bytes);
+ } else {
+ assert(req.is_mutator_alloc(), "Expected mutator alloc here");
+ // padding and actual size both count towards allocation counter
+ generation->increase_allocated(actual_bytes + wasted_bytes);
+
+ // only actual size counts toward usage for mutator allocations
+ increase_used(generation, actual_bytes);
+
+ // notify pacer of both actual size and waste
+ notify_mutator_alloc_words(req.actual_size(), req.waste());
+
+ if (wasted_bytes > 0 && req.actual_size() > ShenandoahHeapRegion::humongous_threshold_words()) {
+ increase_humongous_waste(generation,wasted_bytes);
+ }
+ }
}
! void ShenandoahHeap::increase_humongous_waste(ShenandoahGeneration* generation, size_t bytes) {
! generation->increase_humongous_waste(bytes);
+ if (!generation->is_global()) {
+ global_generation()->increase_humongous_waste(bytes);
+ }
}
! void ShenandoahHeap::decrease_humongous_waste(ShenandoahGeneration* generation, size_t bytes) {
! generation->decrease_humongous_waste(bytes);
! if (!generation->is_global()) {
+ global_generation()->decrease_humongous_waste(bytes);
+ }
}
! void ShenandoahHeap::increase_used(ShenandoahGeneration* generation, size_t bytes) {
! generation->increase_used(bytes);
+ if (!generation->is_global()) {
+ global_generation()->increase_used(bytes);
+ }
}
! void ShenandoahHeap::decrease_used(ShenandoahGeneration* generation, size_t bytes) {
! generation->decrease_used(bytes);
! if (!generation->is_global()) {
! global_generation()->decrease_used(bytes);
}
! }
+
+ void ShenandoahHeap::notify_mutator_alloc_words(size_t words, size_t waste) {
if (ShenandoahPacing) {
control_thread()->pacing_notify_alloc(words);
! if (waste > 0) {
! pacer()->claim_for_alloc(waste, true);
}
}
}
size_t ShenandoahHeap::capacity() const {
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::maybe_uncommit(double shrink_before, size_t shrink_until) {
assert (ShenandoahUncommit, "should be enabled");
// Determine if there is work to do. This avoids taking heap lock if there is
// no work available, avoids spamming logs with superfluous logging messages,
void ShenandoahHeap::notify_heap_changed() {
// Update monitoring counters when we took a new region. This amortizes the
// update costs on slow path.
monitoring_support()->notify_heap_changed();
!
- // This is called from allocation path, and thus should be fast.
- _heap_changed.try_set();
}
void ShenandoahHeap::set_forced_counters_update(bool value) {
monitoring_support()->set_forced_counters_update(value);
}
void ShenandoahHeap::notify_heap_changed() {
// Update monitoring counters when we took a new region. This amortizes the
// update costs on slow path.
monitoring_support()->notify_heap_changed();
! _heap_changed.set();
}
void ShenandoahHeap::set_forced_counters_update(bool value) {
monitoring_support()->set_forced_counters_update(value);
}
// 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;
+
+ // Limit growth of GCLABs to ShenandoahMaxEvacLABRatio * the minimum size. This enables more equitable distribution of
+ // available evacuation buidget between the many threads that are coordinating in the evacuation effort.
+ if (ShenandoahMaxEvacLABRatio > 0) {
+ log_debug(gc, free)("Allocate new gclab: " SIZE_FORMAT ", " SIZE_FORMAT, new_size, PLAB::min_size() * ShenandoahMaxEvacLABRatio);
+ new_size = MIN2(new_size, PLAB::min_size() * ShenandoahMaxEvacLABRatio);
+ }
+
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,
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.
+ log_debug(gc, free)("New gclab size (" SIZE_FORMAT ") is too small for " SIZE_FORMAT, new_size, size);
return nullptr;
}
// Retire current GCLAB, and allocate a new one.
PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
}
gclab->set_buf(gclab_buf, actual_size);
return gclab->allocate(size);
}
+ void ShenandoahHeap::cancel_old_gc() {
+ shenandoah_assert_safepoint();
+ assert(old_generation() != nullptr, "Should only have mixed collections in generation mode.");
+ if (old_generation()->state() == ShenandoahOldGeneration::WAITING_FOR_BOOTSTRAP) {
+ #ifdef ASSERT
+ old_generation()->validate_waiting_for_bootstrap();
+ #endif
+ } else {
+ log_info(gc)("Terminating old gc cycle.");
+ // Stop marking
+ old_generation()->cancel_marking();
+ // Stop tracking old regions
+ old_generation()->abandon_collection_candidates();
+ // Remove old generation access to young generation mark queues
+ young_generation()->set_old_gen_task_queues(nullptr);
+ // Transition to IDLE now.
+ old_generation()->transition_to(ShenandoahOldGeneration::WAITING_FOR_BOOTSTRAP);
+ }
+ }
+
+ // Called from stubs in JIT code or interpreter
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);
*actual_size = 0;
}
return res;
}
+
+ // is_promotion is true iff this allocation is known for sure to hold the result of young-gen evacuation
+ // to old-gen. plab allocates are not known as such, since they may hold old-gen evacuations.
HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
intptr_t pacer_epoch = 0;
bool in_new_region = false;
HeapWord* result = nullptr;
// strategy is to try again, as long as GC makes progress (or until at least
// one full GC has completed).
size_t original_count = shenandoah_policy()->full_gc_count();
while (result == nullptr
&& (get_gc_no_progress_count() == 0 || original_count == shenandoah_policy()->full_gc_count())) {
! control_thread()->handle_alloc_failure(req);
result = allocate_memory_under_lock(req, in_new_region);
}
if (log_is_enabled(Debug, gc, alloc)) {
ResourceMark rm;
log_debug(gc, alloc)("Thread: %s, Result: " PTR_FORMAT ", Request: %s, Size: " SIZE_FORMAT ", Original: " SIZE_FORMAT ", Latest: " SIZE_FORMAT,
Thread::current()->name(), p2i(result), req.type_string(), req.size(), original_count, get_gc_no_progress_count());
}
} 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().
// strategy is to try again, as long as GC makes progress (or until at least
// one full GC has completed).
size_t original_count = shenandoah_policy()->full_gc_count();
while (result == nullptr
&& (get_gc_no_progress_count() == 0 || original_count == shenandoah_policy()->full_gc_count())) {
! control_thread()->handle_alloc_failure(req, true);
result = allocate_memory_under_lock(req, in_new_region);
}
if (log_is_enabled(Debug, gc, alloc)) {
ResourceMark rm;
log_debug(gc, alloc)("Thread: %s, Result: " PTR_FORMAT ", Request: %s, Size: " SIZE_FORMAT ", Original: " SIZE_FORMAT ", Latest: " SIZE_FORMAT,
Thread::current()->name(), p2i(result), req.type_string(), req.size(), original_count, get_gc_no_progress_count());
}
+
} 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) {
notify_heap_changed();
}
if (result != nullptr) {
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) {
! // If we are dealing with mutator allocation, then we may need to block for safepoint.
! // We cannot block for safepoint for GC allocations, because there is a high chance
! // we are already running at safepoint or from stack watermark machinery, and we cannot
! // block again.
! ShenandoahHeapLocker locker(lock(), req.is_mutator_alloc());
! 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);
if (in_new_region) {
notify_heap_changed();
}
+ if (result == nullptr) {
+ req.set_actual_size(0);
+ }
+
+ // This is called regardless of the outcome of the allocation to account
+ // for any waste created by retiring regions with this request.
+ increase_used(req);
+
if (result != nullptr) {
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()) {
// 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);
}
}
}
return result;
}
HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
! bool try_smaller_lab_size = false;
! size_t smaller_lab_size;
! {
! // promotion_eligible pertains only to PLAB allocations, denoting that the PLAB is allowed to allocate for promotions.
! bool promotion_eligible = false;
! bool allow_allocation = true;
+ bool plab_alloc = false;
+ size_t requested_bytes = req.size() * HeapWordSize;
+ HeapWord* result = nullptr;
+
+ // If we are dealing with mutator allocation, then we may need to block for safepoint.
+ // We cannot block for safepoint for GC allocations, because there is a high chance
+ // we are already running at safepoint or from stack watermark machinery, and we cannot
+ // block again.
+ ShenandoahHeapLocker locker(lock(), req.is_mutator_alloc());
+ Thread* thread = Thread::current();
+
+ if (mode()->is_generational()) {
+ if (req.affiliation() == YOUNG_GENERATION) {
+ if (req.is_mutator_alloc()) {
+ size_t young_words_available = young_generation()->available() / HeapWordSize;
+ if (req.is_lab_alloc() && (req.min_size() < young_words_available)) {
+ // Allow ourselves to try a smaller lab size even if requested_bytes <= young_available. We may need a smaller
+ // lab size because young memory has become too fragmented.
+ try_smaller_lab_size = true;
+ smaller_lab_size = (young_words_available < req.size())? young_words_available: req.size();
+ } else if (req.size() > young_words_available) {
+ // Can't allocate because even min_size() is larger than remaining young_available
+ log_info(gc, ergo)("Unable to shrink %s alloc request of minimum size: " SIZE_FORMAT
+ ", young words available: " SIZE_FORMAT, req.type_string(),
+ HeapWordSize * (req.is_lab_alloc()? req.min_size(): req.size()), young_words_available);
+ return nullptr;
+ }
+ }
+ } else { // reg.affiliation() == OLD_GENERATION
+ assert(req.type() != ShenandoahAllocRequest::_alloc_gclab, "GCLAB pertains only to young-gen memory");
+ if (req.type() == ShenandoahAllocRequest::_alloc_plab) {
+ plab_alloc = true;
+ size_t promotion_avail = old_generation()->get_promoted_reserve();
+ size_t promotion_expended = old_generation()->get_promoted_expended();
+ if (promotion_expended + requested_bytes > promotion_avail) {
+ promotion_avail = 0;
+ if (old_generation()->get_evacuation_reserve() == 0) {
+ // There are no old-gen evacuations in this pass. There's no value in creating a plab that cannot
+ // be used for promotions.
+ allow_allocation = false;
+ }
+ } else {
+ promotion_avail = promotion_avail - (promotion_expended + requested_bytes);
+ promotion_eligible = true;
+ }
+ } else if (req.is_promotion()) {
+ // This is a shared alloc for promotion
+ size_t promotion_avail = old_generation()->get_promoted_reserve();
+ size_t promotion_expended = old_generation()->get_promoted_expended();
+ if (promotion_expended + requested_bytes > promotion_avail) {
+ promotion_avail = 0;
+ } else {
+ promotion_avail = promotion_avail - (promotion_expended + requested_bytes);
+ }
+ if (promotion_avail == 0) {
+ // We need to reserve the remaining memory for evacuation. Reject this allocation. The object will be
+ // evacuated to young-gen memory and promoted during a future GC pass.
+ return nullptr;
+ }
+ // Else, we'll allow the allocation to proceed. (Since we hold heap lock, the tested condition remains true.)
+ } else {
+ // This is a shared allocation for evacuation. Memory has already been reserved for this purpose.
+ }
+ }
+ } // This ends the is_generational() block
+
+ // First try the original request. If TLAB request size is greater than available, allocate() will attempt to downsize
+ // request to fit within available memory.
+ result = (allow_allocation)? _free_set->allocate(req, in_new_region): nullptr;
+ if (result != nullptr) {
+ if (req.is_old()) {
+ ShenandoahThreadLocalData::reset_plab_promoted(thread);
+ if (req.is_gc_alloc()) {
+ bool disable_plab_promotions = false;
+ if (req.type() == ShenandoahAllocRequest::_alloc_plab) {
+ if (promotion_eligible) {
+ size_t actual_size = req.actual_size() * HeapWordSize;
+ // The actual size of the allocation may be larger than the requested bytes (due to alignment on card boundaries).
+ // If this puts us over our promotion budget, we need to disable future PLAB promotions for this thread.
+ if (old_generation()->get_promoted_expended() + actual_size <= old_generation()->get_promoted_reserve()) {
+ // Assume the entirety of this PLAB will be used for promotion. This prevents promotion from overreach.
+ // When we retire this plab, we'll unexpend what we don't really use.
+ ShenandoahThreadLocalData::enable_plab_promotions(thread);
+ old_generation()->expend_promoted(actual_size);
+ ShenandoahThreadLocalData::set_plab_preallocated_promoted(thread, actual_size);
+ } else {
+ disable_plab_promotions = true;
+ }
+ } else {
+ disable_plab_promotions = true;
+ }
+ if (disable_plab_promotions) {
+ // Disable promotions in this thread because entirety of this PLAB must be available to hold old-gen evacuations.
+ ShenandoahThreadLocalData::disable_plab_promotions(thread);
+ ShenandoahThreadLocalData::set_plab_preallocated_promoted(thread, 0);
+ }
+ } else if (req.is_promotion()) {
+ // Shared promotion. Assume size is requested_bytes.
+ old_generation()->expend_promoted(requested_bytes);
+ }
+ }
+
+ // Register the newly allocated object while we're holding the global lock since there's no synchronization
+ // built in to the implementation of register_object(). There are potential races when multiple independent
+ // threads are allocating objects, some of which might span the same card region. For example, consider
+ // a card table's memory region within which three objects are being allocated by three different threads:
+ //
+ // objects being "concurrently" allocated:
+ // [-----a------][-----b-----][--------------c------------------]
+ // [---- card table memory range --------------]
+ //
+ // Before any objects are allocated, this card's memory range holds no objects. Note that allocation of object a
+ // wants to set the starts-object, first-start, and last-start attributes of the preceding card region.
+ // allocation of object b wants to set the starts-object, first-start, and last-start attributes of this card region.
+ // allocation of object c also wants to set the starts-object, first-start, and last-start attributes of this
+ // card region.
+ //
+ // The thread allocating b and the thread allocating c can "race" in various ways, resulting in confusion, such as
+ // last-start representing object b while first-start represents object c. This is why we need to require all
+ // register_object() invocations to be "mutually exclusive" with respect to each card's memory range.
+ card_scan()->register_object(result);
+ }
+ } else {
+ // The allocation failed. If this was a plab allocation, We've already retired it and no longer have a plab.
+ if (req.is_old() && req.is_gc_alloc() && (req.type() == ShenandoahAllocRequest::_alloc_plab)) {
+ // We don't need to disable PLAB promotions because there is no PLAB. We leave promotions enabled because
+ // this allows the surrounding infrastructure to retry alloc_plab_slow() with a smaller PLAB size.
+ ShenandoahThreadLocalData::set_plab_preallocated_promoted(thread, 0);
+ }
+ }
+ if ((result != nullptr) || !try_smaller_lab_size) {
+ return result;
+ }
+ // else, fall through to try_smaller_lab_size
+ } // This closes the block that holds the heap lock, releasing the lock.
+
+ // We failed to allocate the originally requested lab size. Let's see if we can allocate a smaller lab size.
+ if (req.size() == smaller_lab_size) {
+ // If we were already trying to allocate min size, no value in attempting to repeat the same. End the recursion.
+ return nullptr;
+ }
+
+ // We arrive here if the tlab allocation request can be resized to fit within young_available
+ assert((req.affiliation() == YOUNG_GENERATION) && req.is_lab_alloc() && req.is_mutator_alloc() &&
+ (smaller_lab_size < req.size()), "Only shrink allocation request size for TLAB allocations");
+
+ // By convention, ShenandoahAllocationRequest is primarily read-only. The only mutable instance data is represented by
+ // actual_size(), which is overwritten with the size of the allocaion when the allocation request is satisfied. We use a
+ // recursive call here rather than introducing new methods to mutate the existing ShenandoahAllocationRequest argument.
+ // Mutation of the existing object might result in astonishing results if calling contexts assume the content of immutable
+ // fields remain constant. The original TLAB allocation request was for memory that exceeded the current capacity. We'll
+ // attempt to allocate a smaller TLAB. If this is successful, we'll update actual_size() of our incoming
+ // ShenandoahAllocRequest. If the recursive request fails, we'll simply return nullptr.
+
+ // Note that we've relinquished the HeapLock and some other thread may perform additional allocation before our recursive
+ // call reacquires the lock. If that happens, we will need another recursive call to further reduce the size of our request
+ // for each time another thread allocates young memory during the brief intervals that the heap lock is available to
+ // interfering threads. We expect this interference to be rare. The recursion bottoms out when young_available is
+ // smaller than req.min_size(). The inner-nested call to allocate_memory_under_lock() uses the same min_size() value
+ // as this call, but it uses a preferred size() that is smaller than our preferred size, and is no larger than what we most
+ // recently saw as the memory currently available within the young generation.
+
+ // TODO: At the expense of code clarity, we could rewrite this recursive solution to use iteration. We need at most one
+ // extra instance of the ShenandoahAllocRequest, which we can re-initialize multiple times inside a loop, with one iteration
+ // of the loop required for each time the existing solution would recurse. An iterative solution would be more efficient
+ // in CPU time and stack memory utilization. The expectation is that it is very rare that we would recurse more than once
+ // so making this change is not currently seen as a high priority.
+
+ ShenandoahAllocRequest smaller_req = ShenandoahAllocRequest::for_tlab(req.min_size(), smaller_lab_size);
+
+ // Note that shrinking the preferred size gets us past the gatekeeper that checks whether there's available memory to
+ // satisfy the allocation request. The reality is the actual TLAB size is likely to be even smaller, because it will
+ // depend on how much memory is available within mutator regions that are not yet fully used.
+ HeapWord* result = allocate_memory_under_lock(smaller_req, in_new_region);
+ if (result != nullptr) {
+ req.set_actual_size(smaller_req.actual_size());
+ }
+ return result;
}
HeapWord* ShenandoahHeap::mem_allocate(size_t size,
bool* gc_overhead_limit_was_exceeded) {
ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
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);
size_t size,
Metaspace::MetadataType mdtype) {
MetaWord* result;
// Inform metaspace OOM to GC heuristics if class unloading is possible.
! ShenandoahHeuristics* h = global_generation()->heuristics();
! if (h->can_unload_classes()) {
h->record_metaspace_oom();
}
// Expand and retry allocation
result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
}
}
};
void ShenandoahHeap::evacuate_collection_set(bool concurrent) {
! ShenandoahEvacuationTask task(this, _collection_set, concurrent);
! workers()->run_task(&task);
}
void ShenandoahHeap::trash_cset_regions() {
ShenandoahHeapLocker locker(lock());
}
}
};
void ShenandoahHeap::evacuate_collection_set(bool concurrent) {
! if (mode()->is_generational()) {
! ShenandoahRegionIterator regions;
+ ShenandoahGenerationalEvacuationTask task(ShenandoahGenerationalHeap::heap(), ®ions, concurrent);
+ workers()->run_task(&task);
+ } else {
+ ShenandoahEvacuationTask task(this, _collection_set, concurrent);
+ workers()->run_task(&task);
+ }
+ }
+
+ oop ShenandoahHeap::evacuate_object(oop p, Thread* thread) {
+ assert(thread == Thread::current(), "Expected thread parameter to be current thread.");
+ if (ShenandoahThreadLocalData::is_oom_during_evac(thread)) {
+ // This thread went through the OOM during evac protocol. It is safe to return
+ // the forward pointer. It must not attempt to evacuate any other objects.
+ return ShenandoahBarrierSet::resolve_forwarded(p);
+ }
+
+ assert(ShenandoahThreadLocalData::is_evac_allowed(thread), "must be enclosed in oom-evac scope");
+
+ ShenandoahHeapRegion* r = heap_region_containing(p);
+ assert(!r->is_humongous(), "never evacuate humongous objects");
+
+ ShenandoahAffiliation target_gen = r->affiliation();
+ return try_evacuate_object(p, thread, r, target_gen);
+ }
+
+ oop ShenandoahHeap::try_evacuate_object(oop p, Thread* thread, ShenandoahHeapRegion* from_region,
+ ShenandoahAffiliation target_gen) {
+ assert(target_gen == YOUNG_GENERATION, "Only expect evacuations to young in this mode");
+ assert(from_region->is_young(), "Only expect evacuations from young in this mode");
+ bool alloc_from_lab = true;
+ HeapWord* copy = nullptr;
+ size_t size = p->size();
+
+ #ifdef ASSERT
+ if (ShenandoahOOMDuringEvacALot &&
+ (os::random() & 1) == 0) { // Simulate OOM every ~2nd slow-path call
+ copy = nullptr;
+ } else {
+ #endif
+ if (UseTLAB) {
+ copy = allocate_from_gclab(thread, size);
+ if ((copy == nullptr) && (size < ShenandoahThreadLocalData::gclab_size(thread))) {
+ // GCLAB allocation failed because we are bumping up against the limit on young evacuation reserve. Try resetting
+ // the desired GCLAB size and retry GCLAB allocation to avoid cascading of shared memory allocations.
+ // TODO: is this right? using PLAB::min_size() here for gc lab size?
+ ShenandoahThreadLocalData::set_gclab_size(thread, PLAB::min_size());
+ copy = allocate_from_gclab(thread, size);
+ // If we still get nullptr, we'll try a shared allocation below.
+ }
+ }
+
+ if (copy == nullptr) {
+ // If we failed to allocate in LAB, we'll try a shared allocation.
+ ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared_gc(size, target_gen);
+ copy = allocate_memory(req);
+ alloc_from_lab = false;
+ }
+ #ifdef ASSERT
+ }
+ #endif
+
+ if (copy == nullptr) {
+ control_thread()->handle_alloc_failure_evac(size);
+
+ _oom_evac_handler.handle_out_of_memory_during_evacuation();
+
+ return ShenandoahBarrierSet::resolve_forwarded(p);
+ }
+
+ // Copy the object:
+ _evac_tracker->begin_evacuation(thread, size * HeapWordSize);
+ Copy::aligned_disjoint_words(cast_from_oop<HeapWord*>(p), copy, size);
+
+ oop copy_val = cast_to_oop(copy);
+
+ // Try to install the new forwarding pointer.
+ ContinuationGCSupport::relativize_stack_chunk(copy_val);
+
+ oop result = ShenandoahForwarding::try_update_forwardee(p, copy_val);
+ if (result == copy_val) {
+ // Successfully evacuated. Our copy is now the public one!
+ _evac_tracker->end_evacuation(thread, size * HeapWordSize);
+ shenandoah_assert_correct(nullptr, copy_val);
+ return copy_val;
+ } else {
+ // Failed to evacuate. We need to deal with the object that is left behind. Since this
+ // new allocation is certainly after TAMS, it will be considered live in the next cycle.
+ // But if it happens to contain references to evacuated regions, those references would
+ // not get updated for this stale copy during this cycle, and we will crash while scanning
+ // it the next cycle.
+ if (alloc_from_lab) {
+ // For LAB allocations, it is enough to rollback the allocation ptr. Either the next
+ // object will overwrite this stale copy, or the filler object on LAB retirement will
+ // do this.
+ ShenandoahThreadLocalData::gclab(thread)->undo_allocation(copy, size);
+ } else {
+ // For non-LAB allocations, we have no way to retract the allocation, and
+ // have to explicitly overwrite the copy with the filler object. With that overwrite,
+ // we have to keep the fwdptr initialized and pointing to our (stale) copy.
+ assert(size >= ShenandoahHeap::min_fill_size(), "previously allocated object known to be larger than min_size");
+ fill_with_object(copy, size);
+ shenandoah_assert_correct(nullptr, copy_val);
+ // For non-LAB allocations, the object has already been registered
+ }
+ shenandoah_assert_correct(nullptr, result);
+ return result;
+ }
}
void ShenandoahHeap::trash_cset_regions() {
ShenandoahHeapLocker locker(lock());
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 = cast_to_oop(start->bottom());
size_t size = humongous_obj->size();
size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
for (size_t i = 0; i < num_regions(); i++) {
get_region(i)->print_on(st);
}
}
! size_t ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
assert(start->is_humongous_start(), "reclaim regions starting with the first one");
oop humongous_obj = cast_to_oop(start->bottom());
size_t size = humongous_obj->size();
size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
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();
}
+ return required_regions;
}
class ShenandoahCheckCleanGCLABClosure : public ThreadClosure {
public:
ShenandoahCheckCleanGCLABClosure() {}
void do_thread(Thread* thread) {
PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
assert(gclab != nullptr, "GCLAB should be initialized for %s", thread->name());
assert(gclab->words_remaining() == 0, "GCLAB should not need retirement");
+
+ if (ShenandoahHeap::heap()->mode()->is_generational()) {
+ PLAB* plab = ShenandoahThreadLocalData::plab(thread);
+ assert(plab != nullptr, "PLAB should be initialized for %s", thread->name());
+ assert(plab->words_remaining() == 0, "PLAB should not need retirement");
+ }
}
};
class ShenandoahRetireGCLABClosure : public ThreadClosure {
private:
assert(gclab != nullptr, "GCLAB should be initialized for %s", thread->name());
gclab->retire();
if (_resize && ShenandoahThreadLocalData::gclab_size(thread) > 0) {
ShenandoahThreadLocalData::set_gclab_size(thread, 0);
}
+
+ if (ShenandoahHeap::heap()->mode()->is_generational()) {
+ PLAB* plab = ShenandoahThreadLocalData::plab(thread);
+ assert(plab != nullptr, "PLAB should be initialized for %s", thread->name());
+
+ // There are two reasons to retire all plabs between old-gen evacuation passes.
+ // 1. We need to make the plab memory parsable by remembered-set scanning.
+ // 2. We need to establish a trustworthy UpdateWaterMark value within each old-gen heap region
+ ShenandoahGenerationalHeap::heap()->retire_plab(plab, thread);
+ if (_resize && ShenandoahThreadLocalData::plab_size(thread) > 0) {
+ ShenandoahThreadLocalData::set_plab_size(thread, 0);
+ }
+ }
}
};
void ShenandoahHeap::labs_make_parsable() {
assert(UseTLAB, "Only call with UseTLAB");
}
}
// Returns size in bytes
size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
! // Return the max allowed size, and let the allocation path
- // figure out the safe size for current allocation.
return ShenandoahHeapRegion::max_tlab_size_bytes();
}
size_t ShenandoahHeap::max_tlab_size() const {
// Returns size in words
}
}
// Returns size in bytes
size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
! // Return the max allowed size, and let the allocation path figure out the safe size for current allocation.
return ShenandoahHeapRegion::max_tlab_size_bytes();
}
size_t ShenandoahHeap::max_tlab_size() const {
// Returns size in words
labs_make_parsable();
}
}
void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
! tcl->do_thread(_control_thread);
workers()->threads_do(tcl);
if (_safepoint_workers != nullptr) {
_safepoint_workers->threads_do(tcl);
}
}
labs_make_parsable();
}
}
void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
! if (_shenandoah_policy->is_at_shutdown()) {
+ return;
+ }
+
+ if (_control_thread != nullptr) {
+ tcl->do_thread(_control_thread);
+ }
+
workers()->threads_do(tcl);
if (_safepoint_workers != nullptr) {
_safepoint_workers->threads_do(tcl);
}
}
ls.cr();
ls.cr();
shenandoah_policy()->print_gc_stats(&ls);
+ ls.cr();
+
+ evac_tracker()->print_global_on(&ls);
+
ls.cr();
ls.cr();
}
}
+ void ShenandoahHeap::on_cycle_start(GCCause::Cause cause, ShenandoahGeneration* generation) {
+ shenandoah_policy()->record_collection_cause(cause);
+
+ set_gc_cause(cause);
+ set_gc_generation(generation);
+
+ generation->heuristics()->record_cycle_start();
+ }
+
+ void ShenandoahHeap::on_cycle_end(ShenandoahGeneration* generation) {
+ generation->heuristics()->record_cycle_end();
+ if (mode()->is_generational() && generation->is_global()) {
+ // If we just completed a GLOBAL GC, claim credit for completion of young-gen and old-gen GC as well
+ young_generation()->heuristics()->record_cycle_end();
+ old_generation()->heuristics()->record_cycle_end();
+ }
+ set_gc_cause(GCCause::_no_gc);
+ }
+
void ShenandoahHeap::verify(VerifyOption vo) {
if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
if (ShenandoahVerify) {
verifier()->verify_generic(vo);
} else {
} else {
heap_region_iterate(blk);
}
}
- class ShenandoahInitMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure {
- private:
- ShenandoahMarkingContext* const _ctx;
- public:
- ShenandoahInitMarkUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
-
- void heap_region_do(ShenandoahHeapRegion* r) {
- assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
- if (r->is_active()) {
- // Check if region needs updating its TAMS. We have updated it already during concurrent
- // reset, so it is very likely we don't need to do another write here.
- if (_ctx->top_at_mark_start(r) != r->top()) {
- _ctx->capture_top_at_mark_start(r);
- }
- } else {
- assert(_ctx->top_at_mark_start(r) == r->top(),
- "Region " SIZE_FORMAT " should already have correct TAMS", r->index());
- }
- }
-
- bool is_thread_safe() { return true; }
- };
-
class ShenandoahRendezvousClosure : public HandshakeClosure {
public:
inline ShenandoahRendezvousClosure() : HandshakeClosure("ShenandoahRendezvous") {}
inline void do_thread(Thread* thread) {}
};
void ShenandoahHeap::recycle_trash() {
free_set()->recycle_trash();
}
- class ShenandoahResetUpdateRegionStateClosure : public ShenandoahHeapRegionClosure {
- private:
- ShenandoahMarkingContext* const _ctx;
- public:
- ShenandoahResetUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
-
- void heap_region_do(ShenandoahHeapRegion* r) {
- if (r->is_active()) {
- // Reset live data and set TAMS optimistically. We would recheck these under the pause
- // anyway to capture any updates that happened since now.
- r->clear_live_data();
- _ctx->capture_top_at_mark_start(r);
- }
- }
-
- bool is_thread_safe() { return true; }
- };
-
- void ShenandoahHeap::prepare_gc() {
- reset_mark_bitmap();
-
- ShenandoahResetUpdateRegionStateClosure cl;
- parallel_heap_region_iterate(&cl);
- }
-
- class ShenandoahFinalMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure {
- private:
- ShenandoahMarkingContext* const _ctx;
- ShenandoahHeapLock* const _lock;
-
- public:
- ShenandoahFinalMarkUpdateRegionStateClosure() :
- _ctx(ShenandoahHeap::heap()->complete_marking_context()), _lock(ShenandoahHeap::heap()->lock()) {}
-
- void heap_region_do(ShenandoahHeapRegion* r) {
- if (r->is_active()) {
- // 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.
- 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));
- }
-
- // 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.
- if (r->is_pinned()) {
- if (r->pin_count() == 0) {
- ShenandoahHeapLocker locker(_lock);
- r->make_unpinned();
- }
- } else {
- if (r->pin_count() > 0) {
- ShenandoahHeapLocker locker(_lock);
- r->make_pinned();
- }
- }
-
- // Remember limit for updating refs. It's guaranteed that we get no
- // from-space-refs written from here on.
- r->set_update_watermark_at_safepoint(r->top());
- } else {
- assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
- assert(_ctx->top_at_mark_start(r) == r->top(),
- "Region " SIZE_FORMAT " should have correct TAMS", r->index());
- }
- }
-
- bool is_thread_safe() { return true; }
- };
-
- void ShenandoahHeap::prepare_regions_and_collection_set(bool concurrent) {
- assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC");
- {
- ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_update_region_states :
- ShenandoahPhaseTimings::degen_gc_final_update_region_states);
- ShenandoahFinalMarkUpdateRegionStateClosure cl;
- parallel_heap_region_iterate(&cl);
-
- assert_pinned_region_status();
- }
-
- {
- ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::choose_cset :
- ShenandoahPhaseTimings::degen_gc_choose_cset);
- ShenandoahHeapLocker locker(lock());
- _collection_set->clear();
- heuristics()->choose_collection_set(_collection_set);
- }
-
- {
- ShenandoahGCPhase phase(concurrent ? ShenandoahPhaseTimings::final_rebuild_freeset :
- ShenandoahPhaseTimings::degen_gc_final_rebuild_freeset);
- ShenandoahHeapLocker locker(lock());
- _free_set->rebuild();
- }
- }
-
void ShenandoahHeap::do_class_unloading() {
_unloader.unload();
}
void ShenandoahHeap::stw_weak_refs(bool full_gc) {
// Weak refs processing
ShenandoahPhaseTimings::Phase phase = full_gc ? ShenandoahPhaseTimings::full_gc_weakrefs
: ShenandoahPhaseTimings::degen_gc_weakrefs;
ShenandoahTimingsTracker t(phase);
ShenandoahGCWorkerPhase worker_phase(phase);
! ref_processor()->process_references(phase, workers(), false /* concurrent */);
}
void ShenandoahHeap::prepare_update_heap_references(bool concurrent) {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
void ShenandoahHeap::recycle_trash() {
free_set()->recycle_trash();
}
void ShenandoahHeap::do_class_unloading() {
_unloader.unload();
}
void ShenandoahHeap::stw_weak_refs(bool full_gc) {
// Weak refs processing
ShenandoahPhaseTimings::Phase phase = full_gc ? ShenandoahPhaseTimings::full_gc_weakrefs
: ShenandoahPhaseTimings::degen_gc_weakrefs;
ShenandoahTimingsTracker t(phase);
ShenandoahGCWorkerPhase worker_phase(phase);
! active_generation()->ref_processor()->process_references(phase, workers(), false /* concurrent */);
}
void ShenandoahHeap::prepare_update_heap_references(bool concurrent) {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at Shenandoah safepoint");
_gc_state.set_cond(mask, value);
_gc_state_changed = true;
}
! void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
! assert(!has_forwarded_objects(), "Not expected before/after mark phase");
! set_gc_state(MARKING, 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(EVACUATION, in_progress);
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at Shenandoah safepoint");
_gc_state.set_cond(mask, value);
_gc_state_changed = true;
}
! void ShenandoahHeap::set_concurrent_young_mark_in_progress(bool in_progress) {
! uint mask;
! assert(!has_forwarded_objects(), "Young marking is not concurrent with evacuation");
! if (!in_progress && is_concurrent_old_mark_in_progress()) {
+ assert(mode()->is_generational(), "Only generational GC has old marking");
+ assert(_gc_state.is_set(MARKING), "concurrent_old_marking_in_progress implies MARKING");
+ // If old-marking is in progress when we turn off YOUNG_MARKING, leave MARKING (and OLD_MARKING) on
+ mask = YOUNG_MARKING;
+ } else {
+ mask = MARKING | YOUNG_MARKING;
+ }
+ set_gc_state(mask, in_progress);
+ manage_satb_barrier(in_progress);
+ }
+
+ void ShenandoahHeap::set_concurrent_old_mark_in_progress(bool in_progress) {
+ #ifdef ASSERT
+ // has_forwarded_objects() iff UPDATEREFS or EVACUATION
+ bool has_forwarded = has_forwarded_objects();
+ bool updating_or_evacuating = _gc_state.is_set(UPDATEREFS | EVACUATION);
+ bool evacuating = _gc_state.is_set(EVACUATION);
+ assert ((has_forwarded == updating_or_evacuating) || (evacuating && !has_forwarded && collection_set()->is_empty()),
+ "Updating or evacuating iff has forwarded objects, or if evacuation phase is promoting in place without forwarding");
+ #endif
+ if (!in_progress && is_concurrent_young_mark_in_progress()) {
+ // If young-marking is in progress when we turn off OLD_MARKING, leave MARKING (and YOUNG_MARKING) on
+ assert(_gc_state.is_set(MARKING), "concurrent_young_marking_in_progress implies MARKING");
+ set_gc_state(OLD_MARKING, in_progress);
+ } else {
+ set_gc_state(MARKING | OLD_MARKING, in_progress);
+ }
+ manage_satb_barrier(in_progress);
+ }
+
+ bool ShenandoahHeap::is_prepare_for_old_mark_in_progress() const {
+ return old_generation()->state() == ShenandoahOldGeneration::FILLING;
+ }
+
+ void ShenandoahHeap::set_aging_cycle(bool in_progress) {
+ _is_aging_cycle.set_cond(in_progress);
+ }
+
+ void ShenandoahHeap::manage_satb_barrier(bool active) {
+ if (is_concurrent_mark_in_progress()) {
+ // Ignore request to deactivate barrier while concurrent mark is in progress.
+ // Do not attempt to re-activate the barrier if it is already active.
+ if (active && !ShenandoahBarrierSet::satb_mark_queue_set().is_active()) {
+ ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(active, !active);
+ }
+ } else {
+ // No concurrent marking is in progress so honor request to deactivate,
+ // but only if the barrier is already active.
+ if (!active && ShenandoahBarrierSet::satb_mark_queue_set().is_active()) {
+ ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(active, !active);
+ }
+ }
}
void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
set_gc_state(EVACUATION, in_progress);
bool ShenandoahHeap::try_cancel_gc() {
jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
return prev == CANCELLABLE;
}
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();
}
void ShenandoahHeap::stw_unload_classes(bool full_gc) {
if (!unload_classes()) return;
bool ShenandoahHeap::try_cancel_gc() {
jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
return prev == CANCELLABLE;
}
+ void ShenandoahHeap::cancel_concurrent_mark() {
+ _young_generation->cancel_marking();
+ _old_generation->cancel_marking();
+ _global_generation->cancel_marking();
+
+ ShenandoahBarrierSet::satb_mark_queue_set().abandon_partial_marking();
+ }
+
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());
+ _cancel_requested_time = os::elapsedTime();
}
}
uint ShenandoahHeap::max_workers() {
return _max_workers;
}
void ShenandoahHeap::stop() {
// The shutdown sequence should be able to terminate when GC is running.
! // Step 1. Notify policy to disable event recording and prevent visiting gc threads during shutdown
_shenandoah_policy->record_shutdown();
! // Step 2. 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 3. Notify GC workers that we are cancelling GC.
cancel_gc(GCCause::_shenandoah_stop_vm);
! // Step 4. Wait until GC worker exits normally.
control_thread()->stop();
}
void ShenandoahHeap::stw_unload_classes(bool full_gc) {
if (!unload_classes()) return;
ShenandoahHeap* heap = ShenandoahHeap::heap();
assert(heap->collection_set() != nullptr, "Sanity");
return (address) heap->collection_set()->biased_map_address();
}
- size_t ShenandoahHeap::bytes_allocated_since_gc_start() const {
- return Atomic::load(&_bytes_allocated_since_gc_start);
- }
-
void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
! Atomic::store(&_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);
}
ShenandoahHeap* heap = ShenandoahHeap::heap();
assert(heap->collection_set() != nullptr, "Sanity");
return (address) heap->collection_set()->biased_map_address();
}
void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
! if (mode()->is_generational()) {
+ young_generation()->reset_bytes_allocated_since_gc_start();
+ old_generation()->reset_bytes_allocated_since_gc_start();
+ }
+
+ global_generation()->reset_bytes_allocated_since_gc_start();
}
void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
_degenerated_gc_in_progress.set_cond(in_progress);
}
#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
ConcurrentGCTimer* ShenandoahHeap::gc_timer() const {
#ifdef ASSERT
void ShenandoahHeap::assert_pinned_region_status() {
for (size_t i = 0; i < num_regions(); i++) {
ShenandoahHeapRegion* r = get_region(i);
! if (active_generation()->contains(r)) {
! assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0),
+ "Region " SIZE_FORMAT " pinning status is inconsistent", i);
+ }
}
}
#endif
ConcurrentGCTimer* ShenandoahHeap::gc_timer() const {
template<bool CONCURRENT>
class ShenandoahUpdateHeapRefsTask : public WorkerTask {
private:
ShenandoahHeap* _heap;
ShenandoahRegionIterator* _regions;
public:
! ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions) :
WorkerTask("Shenandoah Update References"),
_heap(ShenandoahHeap::heap()),
! _regions(regions) {
}
void work(uint worker_id) {
if (CONCURRENT) {
ShenandoahConcurrentWorkerSession worker_session(worker_id);
ShenandoahSuspendibleThreadSetJoiner stsj;
! do_work<ShenandoahConcUpdateRefsClosure>();
} else {
ShenandoahParallelWorkerSession worker_session(worker_id);
! do_work<ShenandoahSTWUpdateRefsClosure>();
}
}
private:
template<class T>
! void do_work() {
T cl;
ShenandoahHeapRegion* r = _regions->next();
! ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
while (r != nullptr) {
HeapWord* update_watermark = r->get_update_watermark();
assert (update_watermark >= r->bottom(), "sanity");
if (r->is_active() && !r->is_cset()) {
! _heap->marked_object_oop_iterate(r, &cl, update_watermark);
}
! if (ShenandoahPacing) {
_heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom()));
}
if (_heap->check_cancelled_gc_and_yield(CONCURRENT)) {
return;
}
r = _regions->next();
}
}
};
void ShenandoahHeap::update_heap_references(bool concurrent) {
assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC");
if (concurrent) {
! ShenandoahUpdateHeapRefsTask<true> task(&_update_refs_iterator);
workers()->run_task(&task);
} else {
! ShenandoahUpdateHeapRefsTask<false> task(&_update_refs_iterator);
workers()->run_task(&task);
}
}
-
class ShenandoahFinalUpdateRefsUpdateRegionStateClosure : public ShenandoahHeapRegionClosure {
private:
ShenandoahHeapLock* const _lock;
public:
! ShenandoahFinalUpdateRefsUpdateRegionStateClosure() : _lock(ShenandoahHeap::heap()->lock()) {}
- void heap_region_do(ShenandoahHeapRegion* r) {
// Drop unnecessary "pinned" state from regions that does not have CP marks
// anymore, as this would allow trashing them.
-
if (r->is_active()) {
if (r->is_pinned()) {
if (r->pin_count() == 0) {
ShenandoahHeapLocker locker(_lock);
r->make_unpinned();
template<bool CONCURRENT>
class ShenandoahUpdateHeapRefsTask : public WorkerTask {
private:
ShenandoahHeap* _heap;
ShenandoahRegionIterator* _regions;
+ ShenandoahRegionChunkIterator* _work_chunks;
+
public:
! explicit ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions,
+ ShenandoahRegionChunkIterator* work_chunks) :
WorkerTask("Shenandoah Update References"),
_heap(ShenandoahHeap::heap()),
! _regions(regions),
+ _work_chunks(work_chunks)
+ {
+ bool old_bitmap_stable = _heap->old_generation()->is_mark_complete();
+ log_info(gc, remset)("Scan remembered set using bitmap: %s", BOOL_TO_STR(old_bitmap_stable));
}
void work(uint worker_id) {
if (CONCURRENT) {
ShenandoahConcurrentWorkerSession worker_session(worker_id);
ShenandoahSuspendibleThreadSetJoiner stsj;
! do_work<ShenandoahConcUpdateRefsClosure>(worker_id);
} else {
ShenandoahParallelWorkerSession worker_session(worker_id);
! do_work<ShenandoahSTWUpdateRefsClosure>(worker_id);
}
}
private:
template<class T>
! void do_work(uint worker_id) {
T cl;
+ if (CONCURRENT && (worker_id == 0)) {
+ // We ask the first worker to replenish the Mutator free set by moving regions previously reserved to hold the
+ // results of evacuation. These reserves are no longer necessary because evacuation has completed.
+ size_t cset_regions = _heap->collection_set()->count();
+ // We cannot transfer any more regions than will be reclaimed when the existing collection set is recycled, because
+ // we need the reclaimed collection set regions to replenish the collector reserves
+ _heap->free_set()->move_collector_sets_to_mutator(cset_regions);
+ }
+ // If !CONCURRENT, there's no value in expanding Mutator free set
+
ShenandoahHeapRegion* r = _regions->next();
! // We update references for global, old, and young collections.
+ assert(_heap->active_generation()->is_mark_complete(), "Expected complete marking");
+ ShenandoahMarkingContext* const ctx = _heap->marking_context();
+ bool is_mixed = _heap->collection_set()->has_old_regions();
while (r != nullptr) {
HeapWord* update_watermark = r->get_update_watermark();
assert (update_watermark >= r->bottom(), "sanity");
+
+ log_debug(gc)("ShenandoahUpdateHeapRefsTask::do_work(%u) looking at region " SIZE_FORMAT, worker_id, r->index());
+ bool region_progress = false;
if (r->is_active() && !r->is_cset()) {
! if (!_heap->mode()->is_generational() || r->is_young()) {
+ _heap->marked_object_oop_iterate(r, &cl, update_watermark);
+ region_progress = true;
+ } else if (r->is_old()) {
+ if (_heap->active_generation()->is_global()) {
+ // Note that GLOBAL collection is not as effectively balanced as young and mixed cycles. This is because
+ // concurrent GC threads are parceled out entire heap regions of work at a time and there
+ // is no "catchup phase" consisting of remembered set scanning, during which parcels of work are smaller
+ // and more easily distributed more fairly across threads.
+
+ // TODO: Consider an improvement to load balance GLOBAL GC.
+ _heap->marked_object_oop_iterate(r, &cl, update_watermark);
+ region_progress = true;
+ }
+ // Otherwise, this is an old region in a young or mixed cycle. Process it during a second phase, below.
+ // Don't bother to report pacing progress in this case.
+ } else {
+ // Because updating of references runs concurrently, it is possible that a FREE inactive region transitions
+ // to a non-free active region while this loop is executing. Whenever this happens, the changing of a region's
+ // active status may propagate at a different speed than the changing of the region's affiliation.
+
+ // When we reach this control point, it is because a race has allowed a region's is_active() status to be seen
+ // by this thread before the region's affiliation() is seen by this thread.
+
+ // It's ok for this race to occur because the newly transformed region does not have any references to be
+ // updated.
+
+ assert(r->get_update_watermark() == r->bottom(),
+ "%s Region " SIZE_FORMAT " is_active but not recognized as YOUNG or OLD so must be newly transitioned from FREE",
+ r->affiliation_name(), r->index());
+ }
}
! if (region_progress && ShenandoahPacing) {
_heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom()));
}
if (_heap->check_cancelled_gc_and_yield(CONCURRENT)) {
return;
}
r = _regions->next();
}
+
+ if (_heap->mode()->is_generational() && !_heap->active_generation()->is_global()) {
+ // Since this is generational and not GLOBAL, we have to process the remembered set. There's no remembered
+ // set processing if not in generational mode or if GLOBAL mode.
+
+ // After this thread has exhausted its traditional update-refs work, it continues with updating refs within remembered set.
+ // The remembered set workload is better balanced between threads, so threads that are "behind" can catch up with other
+ // threads during this phase, allowing all threads to work more effectively in parallel.
+ struct ShenandoahRegionChunk assignment;
+ RememberedScanner* scanner = _heap->card_scan();
+
+ while (!_heap->check_cancelled_gc_and_yield(CONCURRENT) && _work_chunks->next(&assignment)) {
+ // Keep grabbing next work chunk to process until finished, or asked to yield
+ ShenandoahHeapRegion* r = assignment._r;
+ if (r->is_active() && !r->is_cset() && r->is_old()) {
+ HeapWord* start_of_range = r->bottom() + assignment._chunk_offset;
+ HeapWord* end_of_range = r->get_update_watermark();
+ if (end_of_range > start_of_range + assignment._chunk_size) {
+ end_of_range = start_of_range + assignment._chunk_size;
+ }
+
+ // Old region in a young cycle or mixed cycle.
+ if (is_mixed) {
+ // TODO: For mixed evac, consider building an old-gen remembered set that allows restricted updating
+ // within old-gen HeapRegions. This remembered set can be constructed by old-gen concurrent marking
+ // and augmented by card marking. For example, old-gen concurrent marking can remember for each old-gen
+ // card which other old-gen regions it refers to: none, one-other specifically, multiple-other non-specific.
+ // Update-references when _mixed_evac processess each old-gen memory range that has a traditional DIRTY
+ // card or if the "old-gen remembered set" indicates that this card holds pointers specifically to an
+ // old-gen region in the most recent collection set, or if this card holds pointers to other non-specific
+ // old-gen heap regions.
+
+ if (r->is_humongous()) {
+ if (start_of_range < end_of_range) {
+ // Need to examine both dirty and clean cards during mixed evac.
+ r->oop_iterate_humongous_slice(&cl, false, start_of_range, assignment._chunk_size, true);
+ }
+ } else {
+ // Since this is mixed evacuation, old regions that are candidates for collection have not been coalesced
+ // and filled. Use mark bits to find objects that need to be updated.
+ //
+ // Future TODO: establish a second remembered set to identify which old-gen regions point to other old-gen
+ // regions which are in the collection set for a particular mixed evacuation.
+ if (start_of_range < end_of_range) {
+ HeapWord* p = nullptr;
+ size_t card_index = scanner->card_index_for_addr(start_of_range);
+ // In case last object in my range spans boundary of my chunk, I may need to scan all the way to top()
+ ShenandoahObjectToOopBoundedClosure<T> objs(&cl, start_of_range, r->top());
+
+ // Any object that begins in a previous range is part of a different scanning assignment. Any object that
+ // starts after end_of_range is also not my responsibility. (Either allocated during evacuation, so does
+ // not hold pointers to from-space, or is beyond the range of my assigned work chunk.)
+
+ // Find the first object that begins in my range, if there is one.
+ p = start_of_range;
+ oop obj = cast_to_oop(p);
+ HeapWord* tams = ctx->top_at_mark_start(r);
+ if (p >= tams) {
+ // We cannot use ctx->is_marked(obj) to test whether an object begins at this address. Instead,
+ // we need to use the remembered set crossing map to advance p to the first object that starts
+ // within the enclosing card.
+
+ while (true) {
+ HeapWord* first_object = scanner->first_object_in_card(card_index);
+ if (first_object != nullptr) {
+ p = first_object;
+ break;
+ } else if (scanner->addr_for_card_index(card_index + 1) < end_of_range) {
+ card_index++;
+ } else {
+ // Force the loop that follows to immediately terminate.
+ p = end_of_range;
+ break;
+ }
+ }
+ obj = cast_to_oop(p);
+ // Note: p may be >= end_of_range
+ } else if (!ctx->is_marked(obj)) {
+ p = ctx->get_next_marked_addr(p, tams);
+ obj = cast_to_oop(p);
+ // If there are no more marked objects before tams, this returns tams.
+ // Note that tams is either >= end_of_range, or tams is the start of an object that is marked.
+ }
+ while (p < end_of_range) {
+ // p is known to point to the beginning of marked object obj
+ objs.do_object(obj);
+ HeapWord* prev_p = p;
+ p += obj->size();
+ if (p < tams) {
+ p = ctx->get_next_marked_addr(p, tams);
+ // If there are no more marked objects before tams, this returns tams. Note that tams is
+ // either >= end_of_range, or tams is the start of an object that is marked.
+ }
+ assert(p != prev_p, "Lack of forward progress");
+ obj = cast_to_oop(p);
+ }
+ }
+ }
+ } else {
+ // This is a young evac..
+ if (start_of_range < end_of_range) {
+ size_t cluster_size =
+ CardTable::card_size_in_words() * ShenandoahCardCluster<ShenandoahDirectCardMarkRememberedSet>::CardsPerCluster;
+ size_t clusters = assignment._chunk_size / cluster_size;
+ assert(clusters * cluster_size == assignment._chunk_size, "Chunk assignment must align on cluster boundaries");
+ scanner->process_region_slice(r, assignment._chunk_offset, clusters, end_of_range, &cl, true, worker_id);
+ }
+ }
+ if (ShenandoahPacing && (start_of_range < end_of_range)) {
+ _heap->pacer()->report_updaterefs(pointer_delta(end_of_range, start_of_range));
+ }
+ }
+ }
+ }
}
};
void ShenandoahHeap::update_heap_references(bool concurrent) {
assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC");
+ uint nworkers = workers()->active_workers();
+ ShenandoahRegionChunkIterator work_list(nworkers);
if (concurrent) {
! ShenandoahUpdateHeapRefsTask<true> task(&_update_refs_iterator, &work_list);
workers()->run_task(&task);
} else {
! ShenandoahUpdateHeapRefsTask<false> task(&_update_refs_iterator, &work_list);
workers()->run_task(&task);
}
+ if (ShenandoahEnableCardStats && card_scan()!=nullptr) { // generational check proxy
+ card_scan()->log_card_stats(nworkers, CARD_STAT_UPDATE_REFS);
+ }
}
class ShenandoahFinalUpdateRefsUpdateRegionStateClosure : public ShenandoahHeapRegionClosure {
private:
+ ShenandoahMarkingContext* _ctx;
ShenandoahHeapLock* const _lock;
+ bool _is_generational;
public:
! ShenandoahFinalUpdateRefsUpdateRegionStateClosure(ShenandoahMarkingContext* ctx) :
+ _ctx(ctx), _lock(ShenandoahHeap::heap()->lock()),
+ _is_generational(ShenandoahHeap::heap()->mode()->is_generational()) { }
+
+ void heap_region_do(ShenandoahHeapRegion* r) override {
+
+ // Maintenance of region age must follow evacuation in order to account for evacuation allocations within survivor
+ // regions. We consult region age during the subsequent evacuation to determine whether certain objects need to
+ // be promoted.
+ if (_is_generational && r->is_young() && r->is_active()) {
+ HeapWord *tams = _ctx->top_at_mark_start(r);
+ HeapWord *top = r->top();
+
+ // Allocations move the watermark when top moves. However, compacting
+ // objects will sometimes lower top beneath the watermark, after which,
+ // attempts to read the watermark will assert out (watermark should not be
+ // higher than top).
+ if (top > tams) {
+ // There have been allocations in this region since the start of the cycle.
+ // Any objects new to this region must not assimilate elevated age.
+ r->reset_age();
+ } else if (ShenandoahHeap::heap()->is_aging_cycle()) {
+ r->increment_age();
+ }
+ }
// Drop unnecessary "pinned" state from regions that does not have CP marks
// anymore, as this would allow trashing them.
if (r->is_active()) {
if (r->is_pinned()) {
if (r->pin_count() == 0) {
ShenandoahHeapLocker locker(_lock);
r->make_unpinned();
}
}
}
}
! bool is_thread_safe() { return true; }
};
void ShenandoahHeap::update_heap_region_states(bool concurrent) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC");
{
ShenandoahGCPhase phase(concurrent ?
ShenandoahPhaseTimings::final_update_refs_update_region_states :
ShenandoahPhaseTimings::degen_gc_final_update_refs_update_region_states);
! ShenandoahFinalUpdateRefsUpdateRegionStateClosure cl;
parallel_heap_region_iterate(&cl);
assert_pinned_region_status();
}
}
}
}
}
! bool is_thread_safe() override { return true; }
};
void ShenandoahHeap::update_heap_region_states(bool concurrent) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
assert(!is_full_gc_in_progress(), "Only for concurrent and degenerated GC");
{
ShenandoahGCPhase phase(concurrent ?
ShenandoahPhaseTimings::final_update_refs_update_region_states :
ShenandoahPhaseTimings::degen_gc_final_update_refs_update_region_states);
! ShenandoahFinalUpdateRefsUpdateRegionStateClosure cl (active_generation()->complete_marking_context());
parallel_heap_region_iterate(&cl);
assert_pinned_region_status();
}
trash_cset_regions();
}
}
void ShenandoahHeap::rebuild_free_set(bool concurrent) {
! {
! ShenandoahGCPhase phase(concurrent ?
! ShenandoahPhaseTimings::final_update_refs_rebuild_freeset :
! ShenandoahPhaseTimings::degen_gc_final_update_refs_rebuild_freeset);
! ShenandoahHeapLocker locker(lock());
! _free_set->rebuild();
}
}
void ShenandoahHeap::print_extended_on(outputStream *st) const {
print_on(st);
trash_cset_regions();
}
}
void ShenandoahHeap::rebuild_free_set(bool concurrent) {
! ShenandoahGCPhase phase(concurrent ?
! ShenandoahPhaseTimings::final_update_refs_rebuild_freeset :
! ShenandoahPhaseTimings::degen_gc_final_update_refs_rebuild_freeset);
! ShenandoahHeapLocker locker(lock());
! size_t young_cset_regions, old_cset_regions;
! size_t first_old_region, last_old_region, old_region_count;
+ _free_set->prepare_to_rebuild(young_cset_regions, old_cset_regions, first_old_region, last_old_region, old_region_count);
+ // If there are no old regions, first_old_region will be greater than last_old_region
+ assert((first_old_region > last_old_region) ||
+ ((last_old_region + 1 - first_old_region >= old_region_count) &&
+ get_region(first_old_region)->is_old() && get_region(last_old_region)->is_old()),
+ "sanity: old_region_count: " SIZE_FORMAT ", first_old_region: " SIZE_FORMAT ", last_old_region: " SIZE_FORMAT,
+ old_region_count, first_old_region, last_old_region);
+
+ if (mode()->is_generational()) {
+ assert(verify_generation_usage(true, old_generation()->used_regions(),
+ old_generation()->used(), old_generation()->get_humongous_waste(),
+ true, young_generation()->used_regions(),
+ young_generation()->used(), young_generation()->get_humongous_waste()),
+ "Generation accounts are inaccurate");
+
+ // The computation of bytes_of_allocation_runway_before_gc_trigger is quite conservative so consider all of this
+ // available for transfer to old. Note that transfer of humongous regions does not impact available.
+ size_t allocation_runway = young_generation()->heuristics()->bytes_of_allocation_runway_before_gc_trigger(young_cset_regions);
+ ShenandoahGenerationalHeap::heap()->compute_old_generation_balance(allocation_runway, old_cset_regions);
+
+ // Total old_available may have been expanded to hold anticipated promotions. We trigger if the fragmented available
+ // memory represents more than 16 regions worth of data. Note that fragmentation may increase when we promote regular
+ // regions in place when many of these regular regions have an abundant amount of available memory within them. Fragmentation
+ // will decrease as promote-by-copy consumes the available memory within these partially consumed regions.
+ //
+ // We consider old-gen to have excessive fragmentation if more than 12.5% of old-gen is free memory that resides
+ // within partially consumed regions of memory.
+ }
+ // Rebuild free set based on adjusted generation sizes.
+ _free_set->rebuild(young_cset_regions, old_cset_regions);
+
+ if (mode()->is_generational() && (ShenandoahGenerationalHumongousReserve > 0)) {
+ old_generation()->maybe_trigger_collection(first_old_region, last_old_region, old_region_count);
}
}
void ShenandoahHeap::print_extended_on(outputStream *st) const {
print_on(st);
memory_pools.append(_memory_pool);
return memory_pools;
}
MemoryUsage ShenandoahHeap::memory_usage() {
! return _memory_pool->get_memory_usage();
}
ShenandoahRegionIterator::ShenandoahRegionIterator() :
_heap(ShenandoahHeap::heap()),
_index(0) {}
memory_pools.append(_memory_pool);
return memory_pools;
}
MemoryUsage ShenandoahHeap::memory_usage() {
! return MemoryUsage(_initial_size, used(), committed(), max_capacity());
}
ShenandoahRegionIterator::ShenandoahRegionIterator() :
_heap(ShenandoahHeap::heap()),
_index(0) {}
void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
assert(worker_id < _max_workers, "sanity");
assert(_liveness_cache != nullptr, "sanity");
ShenandoahLiveData* ld = _liveness_cache[worker_id];
+
for (uint i = 0; i < num_regions(); i++) {
ShenandoahLiveData live = ld[i];
if (live > 0) {
ShenandoahHeapRegion* r = get_region(i);
r->increase_live_data_gc_words(live);
return true;
}
return false;
}
+
+ void ShenandoahHeap::transfer_old_pointers_from_satb() {
+ _old_generation->transfer_pointers_from_satb();
+ }
+
+ bool ShenandoahHeap::verify_generation_usage(bool verify_old, size_t old_regions, size_t old_bytes, size_t old_waste,
+ bool verify_young, size_t young_regions, size_t young_bytes, size_t young_waste) {
+ size_t tally_old_regions = 0;
+ size_t tally_old_bytes = 0;
+ size_t tally_old_waste = 0;
+ size_t tally_young_regions = 0;
+ size_t tally_young_bytes = 0;
+ size_t tally_young_waste = 0;
+
+ shenandoah_assert_heaplocked_or_safepoint();
+ for (size_t i = 0; i < num_regions(); i++) {
+ ShenandoahHeapRegion* r = get_region(i);
+ if (r->is_old()) {
+ tally_old_regions++;
+ tally_old_bytes += r->used();
+ if (r->is_humongous()) {
+ ShenandoahHeapRegion* start = r->humongous_start_region();
+ HeapWord* obj_addr = start->bottom();
+ oop obj = cast_to_oop(obj_addr);
+ size_t word_size = obj->size();
+ HeapWord* end_addr = obj_addr + word_size;
+ if (end_addr <= r->end()) {
+ tally_old_waste += (r->end() - end_addr) * HeapWordSize;
+ }
+ }
+ } else if (r->is_young()) {
+ tally_young_regions++;
+ tally_young_bytes += r->used();
+ if (r->is_humongous()) {
+ ShenandoahHeapRegion* start = r->humongous_start_region();
+ HeapWord* obj_addr = start->bottom();
+ oop obj = cast_to_oop(obj_addr);
+ size_t word_size = obj->size();
+ HeapWord* end_addr = obj_addr + word_size;
+ if (end_addr <= r->end()) {
+ tally_young_waste += (r->end() - end_addr) * HeapWordSize;
+ }
+ }
+ }
+ }
+ if (verify_young &&
+ ((young_regions != tally_young_regions) || (young_bytes != tally_young_bytes) || (young_waste != tally_young_waste))) {
+ return false;
+ } else if (verify_old &&
+ ((old_regions != tally_old_regions) || (old_bytes != tally_old_bytes) || (old_waste != tally_old_waste))) {
+ return false;
+ } else {
+ return true;
+ }
+ }
+
+ ShenandoahGeneration* ShenandoahHeap::generation_for(ShenandoahAffiliation affiliation) const {
+ if (!mode()->is_generational()) {
+ return global_generation();
+ } else if (affiliation == YOUNG_GENERATION) {
+ return young_generation();
+ } else if (affiliation == OLD_GENERATION) {
+ return old_generation();
+ }
+
+ ShouldNotReachHere();
+ return nullptr;
+ }
+
+ void ShenandoahHeap::log_heap_status(const char* msg) const {
+ if (mode()->is_generational()) {
+ young_generation()->log_status(msg);
+ old_generation()->log_status(msg);
+ } else {
+ global_generation()->log_status(msg);
+ }
+ }
+
+ void ShenandoahHeap::clear_cards_for(ShenandoahHeapRegion* region) {
+ if (mode()->is_generational()) {
+ _card_scan->mark_range_as_empty(region->bottom(), pointer_delta(region->end(), region->bottom()));
+ }
+ }
+
+ void ShenandoahHeap::mark_card_as_dirty(void* location) {
+ if (mode()->is_generational()) {
+ _card_scan->mark_card_as_dirty((HeapWord*)location);
+ }
+ }
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