jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/vmGCOperations.cpp@097d78aaf2b5 (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.cpp@097d78aaf2b5 (annotated)

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

Thu, 04 Oct 2012 10:40:23 -0700

author: jmasa
date: Thu, 04 Oct 2012 10:40:23 -0700
changeset 4131: 097d78aaf2b5
parent 4064: 8da5e203b993
child 4497: 16fb9f942703
child 4542: db9981fd3124
permissions: -rw-r--r--

7198873: NPG: VM Does not unload classes with UseConcMarkSweepGC
Reviewed-by: johnc, mgerdin, jwilhelm

 /*
  * Copyright (c) 2005, 2012, 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"
 #ifndef SERIALGC
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #endif
 #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");
   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;
 }
 void VM_GC_HeapInspection::doit() {
   HandleMark hm;
   CollectedHeap* ch = Universe::heap();
   ch->ensure_parsability(false); // must happen, even if collection does
                                  // not happen (e.g. due to GC_locker)
   if (_full_gc) {
     // The collection attempt below would be skipped anyway if
     // 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.
     if (GC_locker::is_active()) {
       warning("GC locker is held; pre-dump GC was skipped");
     } else {
       ch->collect_as_vm_thread(GCCause::_heap_inspection);
     }
   }
   HeapInspection::heap_inspection(_out, _need_prologue /* need_prologue */);
 }
 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);
 }
 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) {
     if (UseConcMarkSweepGC) {
       if (CMSClassUnloadingEnabled) {
         MetaspaceGC::set_should_concurrent_collect(true);
       }
       // For CMS expand since the collection is going to be concurrent.
       _result =
         _loader_data->metaspace_non_null()->expand_and_allocate(_size, _mdtype);
     }
     if (_result == NULL) {
       // Don't clear the soft refs.  This GC is for reclaiming metadata
       // and is unrelated to the fullness of the Java heap which should
       // be the criteria for clearing SoftReferences.
       if (Verbose && PrintGCDetails && UseConcMarkSweepGC) {
         gclog_or_tty->print_cr("\nCMS full GC for Metaspace");
       }
       heap->collect_as_vm_thread(GCCause::_metadata_GC_threshold);
       _result = _loader_data->metaspace_non_null()->allocate(_size, _mdtype);
     }
     if (_result == NULL && !UseConcMarkSweepGC /* CMS already tried */) {
       // 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 (Verbose && PrintGCDetails && _result == NULL) {
       gclog_or_tty->print_cr("\nAfter Metaspace GC failed to allocate size "
                              SIZE_FORMAT, _size);
     }
   }
   if (_result == NULL && GC_locker::is_active_and_needs_gc()) {
     set_gc_locked();
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/vmGCOperations.cpp@097d78aaf2b5 (annotated)

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