8233061: ZGC: Enforce memory ordering in segmented bit maps
Reviewed-by: pliden, stefank
/*
* Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#include "precompiled.hpp"
#include "gc/shared/gcHeapSummary.hpp"
#include "gc/shared/suspendibleThreadSet.hpp"
#include "gc/z/zCollectedHeap.hpp"
#include "gc/z/zGlobals.hpp"
#include "gc/z/zHeap.inline.hpp"
#include "gc/z/zNMethod.hpp"
#include "gc/z/zObjArrayAllocator.hpp"
#include "gc/z/zOop.inline.hpp"
#include "gc/z/zServiceability.hpp"
#include "gc/z/zStat.hpp"
#include "gc/z/zUtils.inline.hpp"
#include "memory/universe.hpp"
#include "runtime/mutexLocker.hpp"
#include "utilities/align.hpp"
ZCollectedHeap* ZCollectedHeap::heap() {
CollectedHeap* heap = Universe::heap();
assert(heap != NULL, "Uninitialized access to ZCollectedHeap::heap()");
assert(heap->kind() == CollectedHeap::Z, "Invalid name");
return (ZCollectedHeap*)heap;
}
ZCollectedHeap::ZCollectedHeap() :
_soft_ref_policy(),
_barrier_set(),
_initialize(&_barrier_set),
_heap(),
_director(new ZDirector()),
_driver(new ZDriver()),
_uncommitter(new ZUncommitter()),
_stat(new ZStat()),
_runtime_workers() {}
CollectedHeap::Name ZCollectedHeap::kind() const {
return CollectedHeap::Z;
}
const char* ZCollectedHeap::name() const {
return ZName;
}
jint ZCollectedHeap::initialize() {
if (!_heap.is_initialized()) {
return JNI_ENOMEM;
}
Universe::calculate_verify_data((HeapWord*)0, (HeapWord*)UINTPTR_MAX);
return JNI_OK;
}
void ZCollectedHeap::initialize_serviceability() {
_heap.serviceability_initialize();
}
void ZCollectedHeap::stop() {
_director->stop();
_driver->stop();
_uncommitter->stop();
_stat->stop();
}
SoftRefPolicy* ZCollectedHeap::soft_ref_policy() {
return &_soft_ref_policy;
}
size_t ZCollectedHeap::max_capacity() const {
return _heap.max_capacity();
}
size_t ZCollectedHeap::capacity() const {
return _heap.capacity();
}
size_t ZCollectedHeap::used() const {
return _heap.used();
}
size_t ZCollectedHeap::unused() const {
return _heap.unused();
}
bool ZCollectedHeap::is_maximal_no_gc() const {
// Not supported
ShouldNotReachHere();
return false;
}
bool ZCollectedHeap::is_in(const void* p) const {
return _heap.is_in((uintptr_t)p);
}
uint32_t ZCollectedHeap::hash_oop(oop obj) const {
return _heap.hash_oop(ZOop::to_address(obj));
}
HeapWord* ZCollectedHeap::allocate_new_tlab(size_t min_size, size_t requested_size, size_t* actual_size) {
const size_t size_in_bytes = ZUtils::words_to_bytes(align_object_size(requested_size));
const uintptr_t addr = _heap.alloc_tlab(size_in_bytes);
if (addr != 0) {
*actual_size = requested_size;
}
return (HeapWord*)addr;
}
oop ZCollectedHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
if (!do_zero) {
return CollectedHeap::array_allocate(klass, size, length, false /* do_zero */, THREAD);
}
ZObjArrayAllocator allocator(klass, size, length, THREAD);
return allocator.allocate();
}
HeapWord* ZCollectedHeap::mem_allocate(size_t size, bool* gc_overhead_limit_was_exceeded) {
const size_t size_in_bytes = ZUtils::words_to_bytes(align_object_size(size));
return (HeapWord*)_heap.alloc_object(size_in_bytes);
}
MetaWord* ZCollectedHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
size_t size,
Metaspace::MetadataType mdtype) {
MetaWord* result;
// Start asynchronous GC
collect(GCCause::_metadata_GC_threshold);
// Expand and retry allocation
result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
if (result != NULL) {
return result;
}
// Start synchronous GC
collect(GCCause::_metadata_GC_clear_soft_refs);
// Retry allocation
result = loader_data->metaspace_non_null()->allocate(size, mdtype);
if (result != NULL) {
return result;
}
// Expand and retry allocation
result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
if (result != NULL) {
return result;
}
// Out of memory
return NULL;
}
void ZCollectedHeap::collect(GCCause::Cause cause) {
_driver->collect(cause);
}
void ZCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
// These collection requests are ignored since ZGC can't run a synchronous
// GC cycle from within the VM thread. This is considered benign, since the
// only GC causes coming in here should be heap dumper and heap inspector.
// However, neither the heap dumper nor the heap inspector really need a GC
// to happen, but the result of their heap iterations might in that case be
// less accurate since they might include objects that would otherwise have
// been collected by a GC.
assert(Thread::current()->is_VM_thread(), "Should be the VM thread");
guarantee(cause == GCCause::_heap_dump ||
cause == GCCause::_heap_inspection, "Invalid cause");
}
void ZCollectedHeap::do_full_collection(bool clear_all_soft_refs) {
// Not supported
ShouldNotReachHere();
}
bool ZCollectedHeap::supports_tlab_allocation() const {
return true;
}
size_t ZCollectedHeap::tlab_capacity(Thread* ignored) const {
return _heap.tlab_capacity();
}
size_t ZCollectedHeap::tlab_used(Thread* ignored) const {
return _heap.tlab_used();
}
size_t ZCollectedHeap::max_tlab_size() const {
return _heap.max_tlab_size();
}
size_t ZCollectedHeap::unsafe_max_tlab_alloc(Thread* ignored) const {
return _heap.unsafe_max_tlab_alloc();
}
bool ZCollectedHeap::can_elide_tlab_store_barriers() const {
return false;
}
bool ZCollectedHeap::can_elide_initializing_store_barrier(oop new_obj) {
// Not supported
ShouldNotReachHere();
return true;
}
bool ZCollectedHeap::card_mark_must_follow_store() const {
// Not supported
ShouldNotReachHere();
return false;
}
GrowableArray<GCMemoryManager*> ZCollectedHeap::memory_managers() {
return GrowableArray<GCMemoryManager*>(1, 1, _heap.serviceability_memory_manager());
}
GrowableArray<MemoryPool*> ZCollectedHeap::memory_pools() {
return GrowableArray<MemoryPool*>(1, 1, _heap.serviceability_memory_pool());
}
void ZCollectedHeap::object_iterate(ObjectClosure* cl) {
_heap.object_iterate(cl, true /* visit_weaks */);
}
void ZCollectedHeap::safe_object_iterate(ObjectClosure* cl) {
_heap.object_iterate(cl, true /* visit_weaks */);
}
void ZCollectedHeap::register_nmethod(nmethod* nm) {
ZNMethod::register_nmethod(nm);
}
void ZCollectedHeap::unregister_nmethod(nmethod* nm) {
ZNMethod::unregister_nmethod(nm);
}
void ZCollectedHeap::flush_nmethod(nmethod* nm) {
ZNMethod::flush_nmethod(nm);
}
void ZCollectedHeap::verify_nmethod(nmethod* nm) {
// Does nothing
}
WorkGang* ZCollectedHeap::get_safepoint_workers() {
return _runtime_workers.workers();
}
jlong ZCollectedHeap::millis_since_last_gc() {
return ZStatCycle::time_since_last() / MILLIUNITS;
}
void ZCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
tc->do_thread(_director);
tc->do_thread(_driver);
tc->do_thread(_uncommitter);
tc->do_thread(_stat);
_heap.worker_threads_do(tc);
_runtime_workers.threads_do(tc);
}
VirtualSpaceSummary ZCollectedHeap::create_heap_space_summary() {
return VirtualSpaceSummary((HeapWord*)0, (HeapWord*)capacity(), (HeapWord*)max_capacity());
}
void ZCollectedHeap::safepoint_synchronize_begin() {
SuspendibleThreadSet::synchronize();
}
void ZCollectedHeap::safepoint_synchronize_end() {
SuspendibleThreadSet::desynchronize();
}
void ZCollectedHeap::prepare_for_verify() {
// Does nothing
}
void ZCollectedHeap::print_on(outputStream* st) const {
_heap.print_on(st);
}
void ZCollectedHeap::print_on_error(outputStream* st) const {
CollectedHeap::print_on_error(st);
st->print_cr( "Heap");
st->print_cr( " GlobalPhase: %u", ZGlobalPhase);
st->print_cr( " GlobalSeqNum: %u", ZGlobalSeqNum);
st->print_cr( " Offset Max: " SIZE_FORMAT_W(-15) " (" PTR_FORMAT ")", ZAddressOffsetMax, ZAddressOffsetMax);
st->print_cr( " Page Size Small: " SIZE_FORMAT_W(-15) " (" PTR_FORMAT ")", ZPageSizeSmall, ZPageSizeSmall);
st->print_cr( " Page Size Medium: " SIZE_FORMAT_W(-15) " (" PTR_FORMAT ")", ZPageSizeMedium, ZPageSizeMedium);
st->print_cr( "Metadata Bits");
st->print_cr( " Good: " PTR_FORMAT, ZAddressGoodMask);
st->print_cr( " Bad: " PTR_FORMAT, ZAddressBadMask);
st->print_cr( " WeakBad: " PTR_FORMAT, ZAddressWeakBadMask);
st->print_cr( " Marked: " PTR_FORMAT, ZAddressMetadataMarked);
st->print_cr( " Remapped: " PTR_FORMAT, ZAddressMetadataRemapped);
}
void ZCollectedHeap::print_extended_on(outputStream* st) const {
_heap.print_extended_on(st);
}
void ZCollectedHeap::print_gc_threads_on(outputStream* st) const {
_director->print_on(st);
st->cr();
_driver->print_on(st);
st->cr();
_uncommitter->print_on(st);
st->cr();
_stat->print_on(st);
st->cr();
_heap.print_worker_threads_on(st);
_runtime_workers.print_threads_on(st);
}
void ZCollectedHeap::print_tracing_info() const {
// Does nothing
}
bool ZCollectedHeap::print_location(outputStream* st, void* addr) const {
return _heap.print_location(st, (uintptr_t)addr);
}
void ZCollectedHeap::verify(VerifyOption option /* ignored */) {
_heap.verify();
}
bool ZCollectedHeap::is_oop(oop object) const {
return _heap.is_oop(ZOop::to_address(object));
}