--- a/src/hotspot/share/gc/cms/cmsVMOperations.cpp Fri Nov 08 14:54:17 2019 +0000
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,255 +0,0 @@
-/*
- * Copyright (c) 2005, 2019, 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 "gc/cms/cmsHeap.hpp"
-#include "gc/cms/cmsVMOperations.hpp"
-#include "gc/cms/concurrentMarkSweepGeneration.inline.hpp"
-#include "gc/cms/concurrentMarkSweepThread.hpp"
-#include "gc/shared/gcLocker.hpp"
-#include "gc/shared/gcTimer.hpp"
-#include "gc/shared/gcTraceTime.inline.hpp"
-#include "gc/shared/isGCActiveMark.hpp"
-#include "memory/universe.hpp"
-#include "runtime/handles.inline.hpp"
-#include "runtime/interfaceSupport.inline.hpp"
-#include "runtime/os.hpp"
-#include "utilities/dtrace.hpp"
-
-//////////////////////////////////////////////////////////
-// Methods in abstract class VM_CMS_Operation
-//////////////////////////////////////////////////////////
-void VM_CMS_Operation::verify_before_gc() {
- if (VerifyBeforeGC &&
- CMSHeap::heap()->total_collections() >= VerifyGCStartAt) {
- GCTraceTime(Info, gc, phases, verify) tm("Verify Before", _collector->_gc_timer_cm);
- HandleMark hm;
- FreelistLocker x(_collector);
- MutexLocker y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
- CMSHeap::heap()->prepare_for_verify();
- Universe::verify();
- }
-}
-
-void VM_CMS_Operation::verify_after_gc() {
- if (VerifyAfterGC &&
- CMSHeap::heap()->total_collections() >= VerifyGCStartAt) {
- GCTraceTime(Info, gc, phases, verify) tm("Verify After", _collector->_gc_timer_cm);
- HandleMark hm;
- FreelistLocker x(_collector);
- MutexLocker y(_collector->bitMapLock(), Mutex::_no_safepoint_check_flag);
- Universe::verify();
- }
-}
-
-bool VM_CMS_Operation::lost_race() const {
- if (CMSCollector::abstract_state() == CMSCollector::Idling) {
- // We lost a race to a foreground collection
- // -- there's nothing to do
- return true;
- }
- assert(CMSCollector::abstract_state() == legal_state(),
- "Inconsistent collector state?");
- return false;
-}
-
-bool VM_CMS_Operation::doit_prologue() {
- assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
- assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
- assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
- "Possible deadlock");
-
- Heap_lock->lock();
- if (lost_race()) {
- assert(_prologue_succeeded == false, "Initialized in c'tor");
- Heap_lock->unlock();
- } else {
- _prologue_succeeded = true;
- }
- return _prologue_succeeded;
-}
-
-void VM_CMS_Operation::doit_epilogue() {
- assert(Thread::current()->is_ConcurrentGC_thread(), "just checking");
- assert(!CMSCollector::foregroundGCShouldWait(), "Possible deadlock");
- assert(!ConcurrentMarkSweepThread::cms_thread_has_cms_token(),
- "Possible deadlock");
-
- if (Universe::has_reference_pending_list()) {
- Heap_lock->notify_all();
- }
- Heap_lock->unlock();
-}
-
-//////////////////////////////////////////////////////////
-// Methods in class VM_CMS_Initial_Mark
-//////////////////////////////////////////////////////////
-void VM_CMS_Initial_Mark::doit() {
- if (lost_race()) {
- // Nothing to do.
- return;
- }
- HS_PRIVATE_CMS_INITMARK_BEGIN();
- GCIdMark gc_id_mark(_gc_id);
-
- _collector->_gc_timer_cm->register_gc_pause_start("Initial Mark");
-
- CMSHeap* heap = CMSHeap::heap();
- GCCauseSetter gccs(heap, GCCause::_cms_initial_mark);
-
- VM_CMS_Operation::verify_before_gc();
-
- IsGCActiveMark x; // stop-world GC active
- _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsInitial, heap->gc_cause());
-
- VM_CMS_Operation::verify_after_gc();
-
- _collector->_gc_timer_cm->register_gc_pause_end();
-
- HS_PRIVATE_CMS_INITMARK_END();
-}
-
-//////////////////////////////////////////////////////////
-// Methods in class VM_CMS_Final_Remark_Operation
-//////////////////////////////////////////////////////////
-void VM_CMS_Final_Remark::doit() {
- if (lost_race()) {
- // Nothing to do.
- return;
- }
- HS_PRIVATE_CMS_REMARK_BEGIN();
- GCIdMark gc_id_mark(_gc_id);
-
- _collector->_gc_timer_cm->register_gc_pause_start("Final Mark");
-
- CMSHeap* heap = CMSHeap::heap();
- GCCauseSetter gccs(heap, GCCause::_cms_final_remark);
-
- VM_CMS_Operation::verify_before_gc();
-
- IsGCActiveMark x; // stop-world GC active
- _collector->do_CMS_operation(CMSCollector::CMS_op_checkpointRootsFinal, heap->gc_cause());
-
- VM_CMS_Operation::verify_after_gc();
-
- _collector->save_heap_summary();
- _collector->_gc_timer_cm->register_gc_pause_end();
-
- HS_PRIVATE_CMS_REMARK_END();
-}
-
-// VM operation to invoke a concurrent collection of a
-// GenCollectedHeap heap.
-void VM_GenCollectFullConcurrent::doit() {
- assert(Thread::current()->is_VM_thread(), "Should be VM thread");
- assert(GCLockerInvokesConcurrent || ExplicitGCInvokesConcurrent, "Unexpected");
-
- CMSHeap* heap = CMSHeap::heap();
- if (_gc_count_before == heap->total_collections()) {
- // The "full" of do_full_collection call below "forces"
- // a collection; the second arg, 0, below ensures that
- // only the young gen is collected. XXX In the future,
- // we'll probably need to have something in this interface
- // to say do this only if we are sure we will not bail
- // out to a full collection in this attempt, but that's
- // for the future.
- assert(SafepointSynchronize::is_at_safepoint(),
- "We can only be executing this arm of if at a safepoint");
- GCCauseSetter gccs(heap, _gc_cause);
- heap->do_full_collection(heap->must_clear_all_soft_refs(), GenCollectedHeap::YoungGen);
- } // Else no need for a foreground young gc
- assert((_gc_count_before < heap->total_collections()) ||
- (GCLocker::is_active() /* gc may have been skipped */
- && (_gc_count_before == heap->total_collections())),
- "total_collections() should be monotonically increasing");
-
- MutexLocker x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
- assert(_full_gc_count_before <= heap->total_full_collections(), "Error");
- if (heap->total_full_collections() == _full_gc_count_before) {
- // Nudge the CMS thread to start a concurrent collection.
- CMSCollector::request_full_gc(_full_gc_count_before, _gc_cause);
- } else {
- assert(_full_gc_count_before < heap->total_full_collections(), "Error");
- FullGCCount_lock->notify_all(); // Inform the Java thread its work is done
- }
-}
-
-bool VM_GenCollectFullConcurrent::evaluate_at_safepoint() const {
- Thread* thr = Thread::current();
- assert(thr != NULL, "Unexpected tid");
- if (!thr->is_Java_thread()) {
- assert(thr->is_VM_thread(), "Expected to be evaluated by VM thread");
- CMSHeap* heap = CMSHeap::heap();
- if (_gc_count_before != heap->total_collections()) {
- // No need to do a young gc, we'll just nudge the CMS thread
- // in the doit() method above, to be executed soon.
- assert(_gc_count_before < heap->total_collections(),
- "total_collections() should be monotonically increasing");
- return false; // no need for foreground young gc
- }
- }
- return true; // may still need foreground young gc
-}
-
-
-void VM_GenCollectFullConcurrent::doit_epilogue() {
- Thread* thr = Thread::current();
- assert(thr->is_Java_thread(), "just checking");
- JavaThread* jt = (JavaThread*)thr;
-
- if (Universe::has_reference_pending_list()) {
- Heap_lock->notify_all();
- }
- Heap_lock->unlock();
-
- // It is fine to test whether completed collections has
- // exceeded our request count without locking because
- // the completion count is monotonically increasing;
- // this will break for very long-running apps when the
- // count overflows and wraps around. XXX fix me !!!
- // e.g. at the rate of 1 full gc per ms, this could
- // overflow in about 1000 years.
- CMSHeap* heap = CMSHeap::heap();
- if (_gc_cause != GCCause::_gc_locker &&
- heap->total_full_collections_completed() <= _full_gc_count_before) {
- // maybe we should change the condition to test _gc_cause ==
- // GCCause::_java_lang_system_gc or GCCause::_dcmd_gc_run,
- // instead of _gc_cause != GCCause::_gc_locker
- assert(GCCause::is_user_requested_gc(_gc_cause),
- "the only way to get here if this was a System.gc()-induced GC");
- assert(ExplicitGCInvokesConcurrent, "Error");
- // Now, wait for witnessing concurrent gc cycle to complete,
- // but do so in native mode, because we want to lock the
- // FullGCEvent_lock, which may be needed by the VM thread
- // or by the CMS thread, so we do not want to be suspended
- // while holding that lock.
- ThreadToNativeFromVM native(jt);
- MutexLocker ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
- // Either a concurrent or a stop-world full gc is sufficient
- // witness to our request.
- while (heap->total_full_collections_completed() <= _full_gc_count_before) {
- FullGCCount_lock->wait_without_safepoint_check();
- }
- }
-}