Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2005, 2014, 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_implementation/shared/vmGCOperations.hpp"

 #include "memory/gcLocker.inline.hpp"

 #include "memory/genCollectedHeap.hpp"

 #include "memory/oopFactory.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/preserveException.hpp"

 #include "utilities/macros.hpp"

 #if INCLUDE_ALL_GCS

 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

 #endif // INCLUDE_ALL_GCS

 #ifndef USDT2

 HS_DTRACE_PROBE_DECL1(hotspot, gc__begin, bool);

 HS_DTRACE_PROBE_DECL(hotspot, gc__end);

 #endif /* !USDT2 */

 // 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) {

 #ifndef USDT2

   HS_DTRACE_PROBE1(hotspot, gc__begin, full);

   HS_DTRACE_WORKAROUND_TAIL_CALL_BUG();

 #else /* USDT2 */

   HOTSPOT_GC_BEGIN(

                    full);

 #endif /* USDT2 */

 }

 void VM_GC_Operation::notify_gc_end() {

 #ifndef USDT2

   HS_DTRACE_PROBE(hotspot, gc__end);

   HS_DTRACE_WORKAROUND_TAIL_CALL_BUG();

 #else /* USDT2 */

   HOTSPOT_GC_END(

 );

 #endif /* USDT2 */

 }

 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 signalled,

 // 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 && GC_locker::is_active_and_needs_gc()) {

     skip = Universe::heap()->is_maximal_no_gc();

     assert(!(skip && (_gc_cause == GCCause::_gc_locker)),

            "GC_locker 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 " UINTX_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;

     SharedHeap* sh = SharedHeap::heap();

     if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = true;

   }

   return _prologue_succeeded;

 }

 void VM_GC_Operation::doit_epilogue() {

   assert(Thread::current()->is_Java_thread(), "just checking");

   // Release the Heap_lock first.

   SharedHeap* sh = SharedHeap::heap();

   if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = false;

   Heap_lock->unlock();

   release_and_notify_pending_list_lock();

 }

 bool VM_GC_HeapInspection::doit_prologue() {

   if (Universe::heap()->supports_heap_inspection()) {

     return VM_GC_Operation::doit_prologue();

   } else {

     return false;

   }

 }

 bool VM_GC_HeapInspection::skip_operation() const {

   assert(Universe::heap()->supports_heap_inspection(), "huh?");

   return false;

 }

 bool VM_GC_HeapInspection::collect() {

   if (GC_locker::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 GC_locker)

                                                // 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);

   _res = gch->satisfy_failed_allocation(_size, _tlab);

   assert(gch->is_in_reserved_or_null(_res), "result not in heap");

   if (_res == NULL && GC_locker::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_level);

 }

 // 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()->set_initiate_conc_mark_if_possible();

     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;

 }

 static void log_metaspace_alloc_failure_for_concurrent_GC() {

   if (Verbose && PrintGCDetails) {

     if (UseConcMarkSweepGC) {

       gclog_or_tty->print_cr("\nCMS full GC for Metaspace");

     } else if (UseG1GC) {

       gclog_or_tty->print_cr("\nG1 full GC for Metaspace");

     }

   }

 }

 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_metaspace_alloc_failure_for_concurrent_GC();

   }

   // 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;

   }

   if (Verbose && PrintGCDetails) {

     gclog_or_tty->print_cr("\nAfter Metaspace GC failed to allocate size "

                            SIZE_FORMAT, _size);

   }

   if (GC_locker::is_active_and_needs_gc()) {

     set_gc_locked();

   }

 }