duke@435: /*
stefank@6994:  * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/classLoader.hpp"
stefank@2314: #include "classfile/javaClasses.hpp"
stefank@2314: #include "gc_implementation/shared/vmGCOperations.hpp"
stefank@2314: #include "memory/gcLocker.inline.hpp"
stefank@2314: #include "memory/genCollectedHeap.hpp"
stefank@2314: #include "memory/oopFactory.hpp"
stefank@2314: #include "oops/instanceKlass.hpp"
stefank@2314: #include "oops/instanceRefKlass.hpp"
stefank@2314: #include "runtime/handles.inline.hpp"
stefank@2314: #include "runtime/init.hpp"
stefank@2314: #include "runtime/interfaceSupport.hpp"
stefank@2314: #include "utilities/dtrace.hpp"
stefank@2314: #include "utilities/preserveException.hpp"
jprovino@4542: #include "utilities/macros.hpp"
jprovino@4542: #if INCLUDE_ALL_GCS
stefank@2314: #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
jprovino@4542: #endif // INCLUDE_ALL_GCS
kamg@2445: 
dcubed@3202: #ifndef USDT2
duke@435: HS_DTRACE_PROBE_DECL1(hotspot, gc__begin, bool);
duke@435: HS_DTRACE_PROBE_DECL(hotspot, gc__end);
dcubed@3202: #endif /* !USDT2 */
duke@435: 
duke@435: // The same dtrace probe can't be inserted in two different files, so we
duke@435: // have to call it here, so it's only in one file.  Can't create new probes
duke@435: // for the other file anymore.   The dtrace probes have to remain stable.
duke@435: void VM_GC_Operation::notify_gc_begin(bool full) {
dcubed@3202: #ifndef USDT2
duke@435:   HS_DTRACE_PROBE1(hotspot, gc__begin, full);
jcoomes@1902:   HS_DTRACE_WORKAROUND_TAIL_CALL_BUG();
dcubed@3202: #else /* USDT2 */
dcubed@3202:   HOTSPOT_GC_BEGIN(
dcubed@3202:                    full);
dcubed@3202: #endif /* USDT2 */
duke@435: }
duke@435: 
duke@435: void VM_GC_Operation::notify_gc_end() {
dcubed@3202: #ifndef USDT2
duke@435:   HS_DTRACE_PROBE(hotspot, gc__end);
jcoomes@1902:   HS_DTRACE_WORKAROUND_TAIL_CALL_BUG();
dcubed@3202: #else /* USDT2 */
dcubed@3202:   HOTSPOT_GC_END(
dcubed@3202: );
dcubed@3202: #endif /* USDT2 */
duke@435: }
duke@435: 
duke@435: void VM_GC_Operation::acquire_pending_list_lock() {
duke@435:   // we may enter this with pending exception set
coleenp@4047:   InstanceRefKlass::acquire_pending_list_lock(&_pending_list_basic_lock);
duke@435: }
duke@435: 
duke@435: 
duke@435: void VM_GC_Operation::release_and_notify_pending_list_lock() {
duke@435: 
coleenp@4047:   InstanceRefKlass::release_and_notify_pending_list_lock(&_pending_list_basic_lock);
duke@435: }
duke@435: 
duke@435: // Allocations may fail in several threads at about the same time,
duke@435: // resulting in multiple gc requests.  We only want to do one of them.
duke@435: // In case a GC locker is active and the need for a GC is already signalled,
duke@435: // we want to skip this GC attempt altogether, without doing a futile
duke@435: // safepoint operation.
duke@435: bool VM_GC_Operation::skip_operation() const {
duke@435:   bool skip = (_gc_count_before != Universe::heap()->total_collections());
duke@435:   if (_full && skip) {
duke@435:     skip = (_full_gc_count_before != Universe::heap()->total_full_collections());
duke@435:   }
duke@435:   if (!skip && GC_locker::is_active_and_needs_gc()) {
duke@435:     skip = Universe::heap()->is_maximal_no_gc();
duke@435:     assert(!(skip && (_gc_cause == GCCause::_gc_locker)),
duke@435:            "GC_locker cannot be active when initiating GC");
duke@435:   }
duke@435:   return skip;
duke@435: }
duke@435: 
duke@435: bool VM_GC_Operation::doit_prologue() {
duke@435:   assert(Thread::current()->is_Java_thread(), "just checking");
brutisso@2532:   assert(((_gc_cause != GCCause::_no_gc) &&
brutisso@2532:           (_gc_cause != GCCause::_no_cause_specified)), "Illegal GCCause");
duke@435: 
sjohanss@6619:   // To be able to handle a GC the VM initialization needs to be completed.
sjohanss@6619:   if (!is_init_completed()) {
sjohanss@6619:     vm_exit_during_initialization(
sjohanss@6619:       err_msg("GC triggered before VM initialization completed. Try increasing "
sjohanss@6619:               "NewSize, current value " UINTX_FORMAT "%s.",
sjohanss@6619:               byte_size_in_proper_unit(NewSize),
sjohanss@6619:               proper_unit_for_byte_size(NewSize)));
sjohanss@6619:   }
sjohanss@6619: 
duke@435:   acquire_pending_list_lock();
duke@435:   // If the GC count has changed someone beat us to the collection
duke@435:   // Get the Heap_lock after the pending_list_lock.
duke@435:   Heap_lock->lock();
ysr@777: 
duke@435:   // Check invocations
duke@435:   if (skip_operation()) {
duke@435:     // skip collection
duke@435:     Heap_lock->unlock();
duke@435:     release_and_notify_pending_list_lock();
duke@435:     _prologue_succeeded = false;
duke@435:   } else {
duke@435:     _prologue_succeeded = true;
ysr@777:     SharedHeap* sh = SharedHeap::heap();
ysr@777:     if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = true;
duke@435:   }
duke@435:   return _prologue_succeeded;
duke@435: }
duke@435: 
duke@435: 
duke@435: void VM_GC_Operation::doit_epilogue() {
duke@435:   assert(Thread::current()->is_Java_thread(), "just checking");
duke@435:   // Release the Heap_lock first.
ysr@777:   SharedHeap* sh = SharedHeap::heap();
ysr@777:   if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = false;
duke@435:   Heap_lock->unlock();
duke@435:   release_and_notify_pending_list_lock();
duke@435: }
duke@435: 
duke@435: bool VM_GC_HeapInspection::doit_prologue() {
duke@435:   if (Universe::heap()->supports_heap_inspection()) {
duke@435:     return VM_GC_Operation::doit_prologue();
duke@435:   } else {
duke@435:     return false;
duke@435:   }
duke@435: }
duke@435: 
duke@435: bool VM_GC_HeapInspection::skip_operation() const {
duke@435:   assert(Universe::heap()->supports_heap_inspection(), "huh?");
duke@435:   return false;
duke@435: }
duke@435: 
sla@5237: bool VM_GC_HeapInspection::collect() {
sla@5237:   if (GC_locker::is_active()) {
sla@5237:     return false;
sla@5237:   }
sla@5237:   Universe::heap()->collect_as_vm_thread(GCCause::_heap_inspection);
sla@5237:   return true;
sla@5237: }
sla@5237: 
duke@435: void VM_GC_HeapInspection::doit() {
duke@435:   HandleMark hm;
sla@5237:   Universe::heap()->ensure_parsability(false); // must happen, even if collection does
sla@5237:                                                // not happen (e.g. due to GC_locker)
sla@5237:                                                // or _full_gc being false
duke@435:   if (_full_gc) {
sla@5237:     if (!collect()) {
sla@5237:       // The collection attempt was skipped because the gc locker is held.
sla@5237:       // The following dump may then be a tad misleading to someone expecting
sla@5237:       // only live objects to show up in the dump (see CR 6944195). Just issue
sla@5237:       // a suitable warning in that case and do not attempt to do a collection.
sla@5237:       // The latter is a subtle point, because even a failed attempt
sla@5237:       // to GC will, in fact, induce one in the future, which we
sla@5237:       // probably want to avoid in this case because the GC that we may
sla@5237:       // be about to attempt holds value for us only
sla@5237:       // if it happens now and not if it happens in the eventual
sla@5237:       // future.
kevinw@1827:       warning("GC locker is held; pre-dump GC was skipped");
kevinw@1827:     }
duke@435:   }
acorn@4497:   HeapInspection inspect(_csv_format, _print_help, _print_class_stats,
acorn@4497:                          _columns);
sla@5237:   inspect.heap_inspection(_out);
duke@435: }
duke@435: 
duke@435: 
duke@435: void VM_GenCollectForAllocation::doit() {
kamg@2445:   SvcGCMarker sgcm(SvcGCMarker::MINOR);
duke@435: 
duke@435:   GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435:   GCCauseSetter gccs(gch, _gc_cause);
duke@435:   _res = gch->satisfy_failed_allocation(_size, _tlab);
duke@435:   assert(gch->is_in_reserved_or_null(_res), "result not in heap");
duke@435: 
duke@435:   if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
duke@435:     set_gc_locked();
duke@435:   }
duke@435: }
duke@435: 
duke@435: void VM_GenCollectFull::doit() {
kamg@2445:   SvcGCMarker sgcm(SvcGCMarker::FULL);
duke@435: 
duke@435:   GenCollectedHeap* gch = GenCollectedHeap::heap();
duke@435:   GCCauseSetter gccs(gch, _gc_cause);
duke@435:   gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);
duke@435: }
apetrusenko@574: 
stefank@6996: // Returns true iff concurrent GCs unloads metadata.
stefank@6992: bool VM_CollectForMetadataAllocation::initiate_concurrent_GC() {
stefank@6992: #if INCLUDE_ALL_GCS
stefank@6994:   if (UseConcMarkSweepGC && CMSClassUnloadingEnabled) {
stefank@6994:     MetaspaceGC::set_should_concurrent_collect(true);
stefank@6994:     return true;
stefank@6994:   }
stefank@6992: 
stefank@6996:   if (UseG1GC && ClassUnloadingWithConcurrentMark) {
stefank@6994:     G1CollectedHeap* g1h = G1CollectedHeap::heap();
stefank@6994:     g1h->g1_policy()->set_initiate_conc_mark_if_possible();
stefank@6992: 
stefank@6994:     GCCauseSetter x(g1h, _gc_cause);
stefank@6992: 
stefank@6994:     // At this point we are supposed to start a concurrent cycle. We
stefank@6994:     // will do so if one is not already in progress.
stefank@6994:     bool should_start = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);
stefank@6994: 
stefank@6994:     if (should_start) {
stefank@6994:       double pause_target = g1h->g1_policy()->max_pause_time_ms();
stefank@6994:       g1h->do_collection_pause_at_safepoint(pause_target);
stefank@6992:     }
stefank@6992:     return true;
stefank@6992:   }
stefank@6992: #endif
stefank@6994: 
stefank@6992:   return false;
stefank@6992: }
stefank@6992: 
stefank@6992: static void log_metaspace_alloc_failure_for_concurrent_GC() {
stefank@6992:   if (Verbose && PrintGCDetails) {
stefank@6992:     if (UseConcMarkSweepGC) {
stefank@6992:       gclog_or_tty->print_cr("\nCMS full GC for Metaspace");
stefank@6992:     } else if (UseG1GC) {
stefank@6992:       gclog_or_tty->print_cr("\nG1 full GC for Metaspace");
stefank@6992:     }
stefank@6992:   }
stefank@6992: }
stefank@6992: 
coleenp@4037: void VM_CollectForMetadataAllocation::doit() {
kamg@2445:   SvcGCMarker sgcm(SvcGCMarker::FULL);
kamg@2445: 
coleenp@4037:   CollectedHeap* heap = Universe::heap();
ysr@777:   GCCauseSetter gccs(heap, _gc_cause);
coleenp@4037: 
coleenp@4037:   // Check again if the space is available.  Another thread
coleenp@4037:   // may have similarly failed a metadata allocation and induced
coleenp@4037:   // a GC that freed space for the allocation.
coleenp@4037:   if (!MetadataAllocationFailALot) {
coleenp@4037:     _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype);
stefank@6992:     if (_result != NULL) {
stefank@6992:       return;
coleenp@4037:     }
coleenp@4037:   }
coleenp@4037: 
stefank@6992:   if (initiate_concurrent_GC()) {
stefank@6992:     // For CMS and G1 expand since the collection is going to be concurrent.
stefank@6992:     _result = _loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype);
stefank@6992:     if (_result != NULL) {
stefank@6992:       return;
stefank@6992:     }
stefank@6992: 
stefank@6992:     log_metaspace_alloc_failure_for_concurrent_GC();
stefank@6992:   }
stefank@6992: 
stefank@6992:   // Don't clear the soft refs yet.
stefank@6992:   heap->collect_as_vm_thread(GCCause::_metadata_GC_threshold);
stefank@6992:   // After a GC try to allocate without expanding.  Could fail
stefank@6992:   // and expansion will be tried below.
stefank@6992:   _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype);
stefank@6992:   if (_result != NULL) {
stefank@6992:     return;
stefank@6992:   }
stefank@6992: 
stefank@6992:   // If still failing, allow the Metaspace to expand.
stefank@6992:   // See delta_capacity_until_GC() for explanation of the
stefank@6992:   // amount of the expansion.
stefank@6992:   // This should work unless there really is no more space
stefank@6992:   // or a MaxMetaspaceSize has been specified on the command line.
stefank@6992:   _result = _loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype);
stefank@6992:   if (_result != NULL) {
stefank@6992:     return;
stefank@6992:   }
stefank@6992: 
stefank@6992:   // If expansion failed, do a last-ditch collection and try allocating
stefank@6992:   // again.  A last-ditch collection will clear softrefs.  This
stefank@6992:   // behavior is similar to the last-ditch collection done for perm
stefank@6992:   // gen when it was full and a collection for failed allocation
stefank@6992:   // did not free perm gen space.
stefank@6992:   heap->collect_as_vm_thread(GCCause::_last_ditch_collection);
stefank@6992:   _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype);
stefank@6992:   if (_result != NULL) {
stefank@6992:     return;
stefank@6992:   }
stefank@6992: 
stefank@6992:   if (Verbose && PrintGCDetails) {
stefank@6992:     gclog_or_tty->print_cr("\nAfter Metaspace GC failed to allocate size "
stefank@6992:                            SIZE_FORMAT, _size);
stefank@6992:   }
stefank@6992: 
stefank@6992:   if (GC_locker::is_active_and_needs_gc()) {
apetrusenko@574:     set_gc_locked();
apetrusenko@574:   }
apetrusenko@574: }