jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/vmGCOperations.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.cpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6619: 9c3dc501b5eb
child 6994: bac98749fe00
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 2005, 2013, 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);
 }
 bool VM_CollectForMetadataAllocation::initiate_concurrent_GC() {
 #if INCLUDE_ALL_GCS
   if (UseConcMarkSweepGC || UseG1GC) {
     if (UseConcMarkSweepGC && CMSClassUnloadingEnabled) {
       MetaspaceGC::set_should_concurrent_collect(true);
     } else if (UseG1GC) {
       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();
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/vmGCOperations.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.cpp