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

 /*

  * Copyright (c) 2005, 2010, 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 "prims/jvmtiExport.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

 HS_DTRACE_PROBE_DECL1(hotspot, gc__begin, bool);

 HS_DTRACE_PROBE_DECL(hotspot, gc__end);

 // 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) {

   HS_DTRACE_PROBE1(hotspot, gc__begin, full);

   HS_DTRACE_WORKAROUND_TAIL_CALL_BUG();

 }

 void VM_GC_Operation::notify_gc_end() {

   HS_DTRACE_PROBE(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 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");

   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() {

   JvmtiGCForAllocationMarker jgcm;

   notify_gc_begin(false);

   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();

   }

   notify_gc_end();

 }

 void VM_GenCollectFull::doit() {

   JvmtiGCFullMarker jgcm;

   notify_gc_begin(true);

   GenCollectedHeap* gch = GenCollectedHeap::heap();

   GCCauseSetter gccs(gch, _gc_cause);

   gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);

   notify_gc_end();

 }

 void VM_GenCollectForPermanentAllocation::doit() {

   JvmtiGCForAllocationMarker jgcm;

   notify_gc_begin(true);

   SharedHeap* heap = (SharedHeap*)Universe::heap();

   GCCauseSetter gccs(heap, _gc_cause);

   switch (heap->kind()) {

     case (CollectedHeap::GenCollectedHeap): {

       GenCollectedHeap* gch = (GenCollectedHeap*)heap;

       gch->do_full_collection(gch->must_clear_all_soft_refs(),

                               gch->n_gens() - 1);

       break;

     }

 #ifndef SERIALGC

     case (CollectedHeap::G1CollectedHeap): {

       G1CollectedHeap* g1h = (G1CollectedHeap*)heap;

       g1h->do_full_collection(_gc_cause == GCCause::_last_ditch_collection);

       break;

     }

 #endif // SERIALGC

     default:

       ShouldNotReachHere();

   }

   _res = heap->perm_gen()->allocate(_size, false);

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

   if (_res == NULL && GC_locker::is_active_and_needs_gc()) {

     set_gc_locked();

   }

   notify_gc_end();

 }