| /* |
| * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "classfile/classLoader.hpp" |
| #include "classfile/javaClasses.hpp" |
| #include "gc/shared/allocTracer.hpp" |
| #include "gc/shared/gcId.hpp" |
| #include "gc/shared/gcLocker.inline.hpp" |
| #include "gc/shared/genCollectedHeap.hpp" |
| #include "gc/shared/vmGCOperations.hpp" |
| #include "memory/oopFactory.hpp" |
| #include "logging/log.hpp" |
| #include "oops/instanceKlass.hpp" |
| #include "oops/instanceRefKlass.hpp" |
| #include "runtime/handles.inline.hpp" |
| #include "runtime/init.hpp" |
| #include "runtime/interfaceSupport.hpp" |
| #include "utilities/dtrace.hpp" |
| #include "utilities/macros.hpp" |
| #include "utilities/preserveException.hpp" |
| #if INCLUDE_ALL_GCS |
| #include "gc/g1/g1CollectedHeap.inline.hpp" |
| #endif // INCLUDE_ALL_GCS |
| |
| VM_GC_Operation::~VM_GC_Operation() { |
| CollectedHeap* ch = Universe::heap(); |
| ch->collector_policy()->set_all_soft_refs_clear(false); |
| } |
| |
| // The same dtrace probe can't be inserted in two different files, so we |
| // have to call it here, so it's only in one file. Can't create new probes |
| // for the other file anymore. The dtrace probes have to remain stable. |
| void VM_GC_Operation::notify_gc_begin(bool full) { |
| HOTSPOT_GC_BEGIN( |
| full); |
| HS_DTRACE_WORKAROUND_TAIL_CALL_BUG(); |
| } |
| |
| void VM_GC_Operation::notify_gc_end() { |
| HOTSPOT_GC_END(); |
| HS_DTRACE_WORKAROUND_TAIL_CALL_BUG(); |
| } |
| |
| void VM_GC_Operation::acquire_pending_list_lock() { |
| // we may enter this with pending exception set |
| InstanceRefKlass::acquire_pending_list_lock(&_pending_list_basic_lock); |
| } |
| |
| |
| void VM_GC_Operation::release_and_notify_pending_list_lock() { |
| |
| InstanceRefKlass::release_and_notify_pending_list_lock(&_pending_list_basic_lock); |
| } |
| |
| // Allocations may fail in several threads at about the same time, |
| // resulting in multiple gc requests. We only want to do one of them. |
| // In case a GC locker is active and the need for a GC is already signaled, |
| // we want to skip this GC attempt altogether, without doing a futile |
| // safepoint operation. |
| bool VM_GC_Operation::skip_operation() const { |
| bool skip = (_gc_count_before != Universe::heap()->total_collections()); |
| if (_full && skip) { |
| skip = (_full_gc_count_before != Universe::heap()->total_full_collections()); |
| } |
| if (!skip && GCLocker::is_active_and_needs_gc()) { |
| skip = Universe::heap()->is_maximal_no_gc(); |
| assert(!(skip && (_gc_cause == GCCause::_gc_locker)), |
| "GCLocker cannot be active when initiating GC"); |
| } |
| return skip; |
| } |
| |
| bool VM_GC_Operation::doit_prologue() { |
| assert(Thread::current()->is_Java_thread(), "just checking"); |
| assert(((_gc_cause != GCCause::_no_gc) && |
| (_gc_cause != GCCause::_no_cause_specified)), "Illegal GCCause"); |
| |
| // To be able to handle a GC the VM initialization needs to be completed. |
| if (!is_init_completed()) { |
| vm_exit_during_initialization( |
| err_msg("GC triggered before VM initialization completed. Try increasing " |
| "NewSize, current value " SIZE_FORMAT "%s.", |
| byte_size_in_proper_unit(NewSize), |
| proper_unit_for_byte_size(NewSize))); |
| } |
| |
| acquire_pending_list_lock(); |
| // If the GC count has changed someone beat us to the collection |
| // Get the Heap_lock after the pending_list_lock. |
| Heap_lock->lock(); |
| |
| // Check invocations |
| if (skip_operation()) { |
| // skip collection |
| Heap_lock->unlock(); |
| release_and_notify_pending_list_lock(); |
| _prologue_succeeded = false; |
| } else { |
| _prologue_succeeded = true; |
| } |
| return _prologue_succeeded; |
| } |
| |
| |
| void VM_GC_Operation::doit_epilogue() { |
| assert(Thread::current()->is_Java_thread(), "just checking"); |
| // Release the Heap_lock first. |
| Heap_lock->unlock(); |
| release_and_notify_pending_list_lock(); |
| } |
| |
| bool VM_GC_HeapInspection::skip_operation() const { |
| return false; |
| } |
| |
| bool VM_GC_HeapInspection::collect() { |
| if (GCLocker::is_active()) { |
| return false; |
| } |
| Universe::heap()->collect_as_vm_thread(GCCause::_heap_inspection); |
| return true; |
| } |
| |
| void VM_GC_HeapInspection::doit() { |
| HandleMark hm; |
| Universe::heap()->ensure_parsability(false); // must happen, even if collection does |
| // not happen (e.g. due to GCLocker) |
| // or _full_gc being false |
| if (_full_gc) { |
| if (!collect()) { |
| // The collection attempt was skipped because the gc locker is held. |
| // The following dump may then be a tad misleading to someone expecting |
| // only live objects to show up in the dump (see CR 6944195). Just issue |
| // a suitable warning in that case and do not attempt to do a collection. |
| // The latter is a subtle point, because even a failed attempt |
| // to GC will, in fact, induce one in the future, which we |
| // probably want to avoid in this case because the GC that we may |
| // be about to attempt holds value for us only |
| // if it happens now and not if it happens in the eventual |
| // future. |
| warning("GC locker is held; pre-dump GC was skipped"); |
| } |
| } |
| HeapInspection inspect(_csv_format, _print_help, _print_class_stats, |
| _columns); |
| inspect.heap_inspection(_out); |
| } |
| |
| |
| void VM_GenCollectForAllocation::doit() { |
| SvcGCMarker sgcm(SvcGCMarker::MINOR); |
| |
| GenCollectedHeap* gch = GenCollectedHeap::heap(); |
| GCCauseSetter gccs(gch, _gc_cause); |
| _result = gch->satisfy_failed_allocation(_word_size, _tlab); |
| assert(gch->is_in_reserved_or_null(_result), "result not in heap"); |
| |
| if (_result == NULL && GCLocker::is_active_and_needs_gc()) { |
| set_gc_locked(); |
| } |
| } |
| |
| void VM_GenCollectFull::doit() { |
| SvcGCMarker sgcm(SvcGCMarker::FULL); |
| |
| GenCollectedHeap* gch = GenCollectedHeap::heap(); |
| GCCauseSetter gccs(gch, _gc_cause); |
| gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_generation); |
| } |
| |
| VM_CollectForMetadataAllocation::VM_CollectForMetadataAllocation(ClassLoaderData* loader_data, |
| size_t size, |
| Metaspace::MetadataType mdtype, |
| uint gc_count_before, |
| uint full_gc_count_before, |
| GCCause::Cause gc_cause) |
| : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true), |
| _loader_data(loader_data), _size(size), _mdtype(mdtype), _result(NULL) { |
| assert(_size != 0, "An allocation should always be requested with this operation."); |
| AllocTracer::send_allocation_requiring_gc_event(_size * HeapWordSize, GCId::peek()); |
| } |
| |
| // Returns true iff concurrent GCs unloads metadata. |
| bool VM_CollectForMetadataAllocation::initiate_concurrent_GC() { |
| #if INCLUDE_ALL_GCS |
| if (UseConcMarkSweepGC && CMSClassUnloadingEnabled) { |
| MetaspaceGC::set_should_concurrent_collect(true); |
| return true; |
| } |
| |
| if (UseG1GC && ClassUnloadingWithConcurrentMark) { |
| G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
| g1h->g1_policy()->collector_state()->set_initiate_conc_mark_if_possible(true); |
| |
| GCCauseSetter x(g1h, _gc_cause); |
| |
| // At this point we are supposed to start a concurrent cycle. We |
| // will do so if one is not already in progress. |
| bool should_start = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause); |
| |
| if (should_start) { |
| double pause_target = g1h->g1_policy()->max_pause_time_ms(); |
| g1h->do_collection_pause_at_safepoint(pause_target); |
| } |
| return true; |
| } |
| #endif |
| |
| return false; |
| } |
| |
| void VM_CollectForMetadataAllocation::doit() { |
| SvcGCMarker sgcm(SvcGCMarker::FULL); |
| |
| CollectedHeap* heap = Universe::heap(); |
| GCCauseSetter gccs(heap, _gc_cause); |
| |
| // Check again if the space is available. Another thread |
| // may have similarly failed a metadata allocation and induced |
| // a GC that freed space for the allocation. |
| if (!MetadataAllocationFailALot) { |
| _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype); |
| if (_result != NULL) { |
| return; |
| } |
| } |
| |
| if (initiate_concurrent_GC()) { |
| // For CMS and G1 expand since the collection is going to be concurrent. |
| _result = _loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype); |
| if (_result != NULL) { |
| return; |
| } |
| |
| log_debug(gc)("%s full GC for Metaspace", UseConcMarkSweepGC ? "CMS" : "G1"); |
| } |
| |
| // Don't clear the soft refs yet. |
| heap->collect_as_vm_thread(GCCause::_metadata_GC_threshold); |
| // After a GC try to allocate without expanding. Could fail |
| // and expansion will be tried below. |
| _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype); |
| if (_result != NULL) { |
| return; |
| } |
| |
| // If still failing, allow the Metaspace to expand. |
| // See delta_capacity_until_GC() for explanation of the |
| // amount of the expansion. |
| // This should work unless there really is no more space |
| // or a MaxMetaspaceSize has been specified on the command line. |
| _result = _loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype); |
| if (_result != NULL) { |
| return; |
| } |
| |
| // If expansion failed, do a last-ditch collection and try allocating |
| // again. A last-ditch collection will clear softrefs. This |
| // behavior is similar to the last-ditch collection done for perm |
| // gen when it was full and a collection for failed allocation |
| // did not free perm gen space. |
| heap->collect_as_vm_thread(GCCause::_last_ditch_collection); |
| _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype); |
| if (_result != NULL) { |
| return; |
| } |
| |
| log_debug(gc)("After Metaspace GC failed to allocate size " SIZE_FORMAT, _size); |
| |
| if (GCLocker::is_active_and_needs_gc()) { |
| set_gc_locked(); |
| } |
| } |
| |
| VM_CollectForAllocation::VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause) |
| : VM_GC_Operation(gc_count_before, cause), _result(NULL), _word_size(word_size) { |
| // Only report if operation was really caused by an allocation. |
| if (_word_size != 0) { |
| AllocTracer::send_allocation_requiring_gc_event(_word_size * HeapWordSize, GCId::peek()); |
| } |
| } |