ysr@777: /*
tonyp@2472:  * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
stefank@2314: #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
stefank@2314: #include "gc_implementation/g1/g1CollectorPolicy.hpp"
stefank@2314: #include "gc_implementation/g1/g1MMUTracker.hpp"
stefank@2314: #include "gc_implementation/g1/vm_operations_g1.hpp"
stefank@2314: #include "memory/resourceArea.hpp"
stefank@2314: #include "runtime/vmThread.hpp"
ysr@777: 
ysr@777: // ======= Concurrent Mark Thread ========
ysr@777: 
ysr@777: // The CM thread is created when the G1 garbage collector is used
ysr@777: 
ysr@777: SurrogateLockerThread*
ysr@777:      ConcurrentMarkThread::_slt = NULL;
ysr@777: 
ysr@777: ConcurrentMarkThread::ConcurrentMarkThread(ConcurrentMark* cm) :
ysr@777:   ConcurrentGCThread(),
ysr@777:   _cm(cm),
ysr@777:   _started(false),
ysr@777:   _in_progress(false),
ysr@777:   _vtime_accum(0.0),
ysr@777:   _vtime_mark_accum(0.0),
ysr@777:   _vtime_count_accum(0.0)
ysr@777: {
ysr@777:   create_and_start();
ysr@777: }
ysr@777: 
ysr@777: class CMCheckpointRootsInitialClosure: public VoidClosure {
ysr@777: 
ysr@777:   ConcurrentMark* _cm;
ysr@777: public:
ysr@777: 
ysr@777:   CMCheckpointRootsInitialClosure(ConcurrentMark* cm) :
ysr@777:     _cm(cm) {}
ysr@777: 
ysr@777:   void do_void(){
ysr@777:     _cm->checkpointRootsInitial();
ysr@777:   }
ysr@777: };
ysr@777: 
ysr@777: class CMCheckpointRootsFinalClosure: public VoidClosure {
ysr@777: 
ysr@777:   ConcurrentMark* _cm;
ysr@777: public:
ysr@777: 
ysr@777:   CMCheckpointRootsFinalClosure(ConcurrentMark* cm) :
ysr@777:     _cm(cm) {}
ysr@777: 
ysr@777:   void do_void(){
ysr@777:     _cm->checkpointRootsFinal(false); // !clear_all_soft_refs
ysr@777:   }
ysr@777: };
ysr@777: 
ysr@777: class CMCleanUp: public VoidClosure {
ysr@777:   ConcurrentMark* _cm;
ysr@777: public:
ysr@777: 
ysr@777:   CMCleanUp(ConcurrentMark* cm) :
ysr@777:     _cm(cm) {}
ysr@777: 
ysr@777:   void do_void(){
ysr@777:     _cm->cleanup();
ysr@777:   }
ysr@777: };
ysr@777: 
ysr@777: 
ysr@777: 
ysr@777: void ConcurrentMarkThread::run() {
ysr@777:   initialize_in_thread();
ysr@777:   _vtime_start = os::elapsedVTime();
ysr@777:   wait_for_universe_init();
ysr@777: 
tonyp@2472:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
tonyp@2472:   G1CollectorPolicy* g1_policy = g1h->g1_policy();
ysr@777:   G1MMUTracker *mmu_tracker = g1_policy->mmu_tracker();
ysr@777:   Thread *current_thread = Thread::current();
ysr@777: 
ysr@777:   while (!_should_terminate) {
ysr@777:     // wait until started is set.
ysr@777:     sleepBeforeNextCycle();
ysr@777:     {
ysr@777:       ResourceMark rm;
ysr@777:       HandleMark   hm;
ysr@777:       double cycle_start = os::elapsedVTime();
ysr@777:       double mark_start_sec = os::elapsedTime();
ysr@777:       char verbose_str[128];
ysr@777: 
ysr@777:       if (PrintGC) {
ysr@777:         gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:         gclog_or_tty->stamp(PrintGCTimeStamps);
tonyp@1054:         gclog_or_tty->print_cr("[GC concurrent-mark-start]");
ysr@777:       }
ysr@777: 
ysr@777:       if (!g1_policy->in_young_gc_mode()) {
ysr@777:         // this ensures the flag is not set if we bail out of the marking
ysr@777:         // cycle; normally the flag is cleared immediately after cleanup
tonyp@2472:         g1h->set_marking_complete();
ysr@777: 
ysr@777:         if (g1_policy->adaptive_young_list_length()) {
ysr@777:           double now = os::elapsedTime();
ysr@777:           double init_prediction_ms = g1_policy->predict_init_time_ms();
ysr@777:           jlong sleep_time_ms = mmu_tracker->when_ms(now, init_prediction_ms);
ysr@777:           os::sleep(current_thread, sleep_time_ms, false);
ysr@777:         }
ysr@777: 
ysr@777:         // We don't have to skip here if we've been asked to restart, because
ysr@777:         // in the worst case we just enqueue a new VM operation to start a
ysr@777:         // marking.  Note that the init operation resets has_aborted()
ysr@777:         CMCheckpointRootsInitialClosure init_cl(_cm);
ysr@777:         strcpy(verbose_str, "GC initial-mark");
ysr@777:         VM_CGC_Operation op(&init_cl, verbose_str);
ysr@777:         VMThread::execute(&op);
ysr@777:       }
ysr@777: 
ysr@777:       int iter = 0;
ysr@777:       do {
ysr@777:         iter++;
ysr@777:         if (!cm()->has_aborted()) {
ysr@777:           _cm->markFromRoots();
ysr@777:         }
ysr@777: 
ysr@777:         double mark_end_time = os::elapsedVTime();
ysr@777:         double mark_end_sec = os::elapsedTime();
ysr@777:         _vtime_mark_accum += (mark_end_time - cycle_start);
ysr@777:         if (!cm()->has_aborted()) {
ysr@777:           if (g1_policy->adaptive_young_list_length()) {
ysr@777:             double now = os::elapsedTime();
ysr@777:             double remark_prediction_ms = g1_policy->predict_remark_time_ms();
ysr@777:             jlong sleep_time_ms = mmu_tracker->when_ms(now, remark_prediction_ms);
ysr@777:             os::sleep(current_thread, sleep_time_ms, false);
ysr@777:           }
ysr@777: 
ysr@777:           if (PrintGC) {
ysr@777:             gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:             gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:             gclog_or_tty->print_cr("[GC concurrent-mark-end, %1.7lf sec]",
ysr@777:                                       mark_end_sec - mark_start_sec);
ysr@777:           }
ysr@777: 
ysr@777:           CMCheckpointRootsFinalClosure final_cl(_cm);
ysr@777:           sprintf(verbose_str, "GC remark");
ysr@777:           VM_CGC_Operation op(&final_cl, verbose_str);
ysr@777:           VMThread::execute(&op);
ysr@777:         }
ysr@777:         if (cm()->restart_for_overflow() &&
ysr@777:             G1TraceMarkStackOverflow) {
ysr@777:           gclog_or_tty->print_cr("Restarting conc marking because of MS overflow "
ysr@777:                                  "in remark (restart #%d).", iter);
ysr@777:         }
ysr@777: 
ysr@777:         if (cm()->restart_for_overflow()) {
ysr@777:           if (PrintGC) {
ysr@777:             gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:             gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:             gclog_or_tty->print_cr("[GC concurrent-mark-restart-for-overflow]");
ysr@777:           }
ysr@777:         }
ysr@777:       } while (cm()->restart_for_overflow());
ysr@777:       double counting_start_time = os::elapsedVTime();
ysr@777: 
ysr@777:       // YSR: These look dubious (i.e. redundant) !!! FIX ME
ysr@777:       slt()->manipulatePLL(SurrogateLockerThread::acquirePLL);
ysr@777:       slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
ysr@777: 
ysr@777:       if (!cm()->has_aborted()) {
ysr@777:         double count_start_sec = os::elapsedTime();
ysr@777:         if (PrintGC) {
ysr@777:           gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:           gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:           gclog_or_tty->print_cr("[GC concurrent-count-start]");
ysr@777:         }
ysr@777: 
ysr@777:         _sts.join();
ysr@777:         _cm->calcDesiredRegions();
ysr@777:         _sts.leave();
ysr@777: 
ysr@777:         if (!cm()->has_aborted()) {
ysr@777:           double count_end_sec = os::elapsedTime();
ysr@777:           if (PrintGC) {
ysr@777:             gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:             gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:             gclog_or_tty->print_cr("[GC concurrent-count-end, %1.7lf]",
ysr@777:                                    count_end_sec - count_start_sec);
ysr@777:           }
ysr@777:         }
ysr@777:       }
ysr@777:       double end_time = os::elapsedVTime();
ysr@777:       _vtime_count_accum += (end_time - counting_start_time);
ysr@777:       // Update the total virtual time before doing this, since it will try
ysr@777:       // to measure it to get the vtime for this marking.  We purposely
ysr@777:       // neglect the presumably-short "completeCleanup" phase here.
ysr@777:       _vtime_accum = (end_time - _vtime_start);
ysr@777:       if (!cm()->has_aborted()) {
ysr@777:         if (g1_policy->adaptive_young_list_length()) {
ysr@777:           double now = os::elapsedTime();
ysr@777:           double cleanup_prediction_ms = g1_policy->predict_cleanup_time_ms();
ysr@777:           jlong sleep_time_ms = mmu_tracker->when_ms(now, cleanup_prediction_ms);
ysr@777:           os::sleep(current_thread, sleep_time_ms, false);
ysr@777:         }
ysr@777: 
ysr@777:         CMCleanUp cl_cl(_cm);
ysr@777:         sprintf(verbose_str, "GC cleanup");
ysr@777:         VM_CGC_Operation op(&cl_cl, verbose_str);
ysr@777:         VMThread::execute(&op);
ysr@777:       } else {
tonyp@2472:         g1h->set_marking_complete();
ysr@777:       }
ysr@777: 
tonyp@2472:       // Check if cleanup set the free_regions_coming flag. If it
tonyp@2472:       // hasn't, we can just skip the next step.
tonyp@2472:       if (g1h->free_regions_coming()) {
tonyp@2472:         // The following will finish freeing up any regions that we
tonyp@2472:         // found to be empty during cleanup. We'll do this part
tonyp@2472:         // without joining the suspendible set. If an evacuation pause
tonyp@2472:         // takes places, then we would carry on freeing regions in
tonyp@2472:         // case they are needed by the pause. If a Full GC takes
tonyp@2472:         // places, it would wait for us to process the regions
tonyp@2472:         // reclaimed by cleanup.
tonyp@2472: 
ysr@777:         double cleanup_start_sec = os::elapsedTime();
ysr@777:         if (PrintGC) {
ysr@777:           gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:           gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:           gclog_or_tty->print_cr("[GC concurrent-cleanup-start]");
ysr@777:         }
ysr@777: 
ysr@777:         // Now do the remainder of the cleanup operation.
ysr@777:         _cm->completeCleanup();
tonyp@2501:         // Notify anyone who's waiting that there are no more free
tonyp@2501:         // regions coming. We have to do this before we join the STS,
tonyp@2501:         // otherwise we might deadlock: a GC worker could be blocked
tonyp@2501:         // waiting for the notification whereas this thread will be
tonyp@2501:         // blocked for the pause to finish while it's trying to join
tonyp@2501:         // the STS, which is conditional on the GC workers finishing.
tonyp@2501:         g1h->reset_free_regions_coming();
tonyp@2501: 
tonyp@2492:         _sts.join();
tonyp@2472:         g1_policy->record_concurrent_mark_cleanup_completed();
tonyp@2492:         _sts.leave();
ysr@777: 
tonyp@2472:         double cleanup_end_sec = os::elapsedTime();
tonyp@2472:         if (PrintGC) {
tonyp@2472:           gclog_or_tty->date_stamp(PrintGCDateStamps);
tonyp@2472:           gclog_or_tty->stamp(PrintGCTimeStamps);
tonyp@2472:           gclog_or_tty->print_cr("[GC concurrent-cleanup-end, %1.7lf]",
tonyp@2472:                                  cleanup_end_sec - cleanup_start_sec);
ysr@777:         }
ysr@777:       }
tonyp@2472:       guarantee(cm()->cleanup_list_is_empty(),
tonyp@2472:                 "at this point there should be no regions on the cleanup list");
ysr@777: 
ysr@777:       if (cm()->has_aborted()) {
ysr@777:         if (PrintGC) {
ysr@777:           gclog_or_tty->date_stamp(PrintGCDateStamps);
ysr@777:           gclog_or_tty->stamp(PrintGCTimeStamps);
ysr@777:           gclog_or_tty->print_cr("[GC concurrent-mark-abort]");
ysr@777:         }
ysr@777:       }
ysr@777: 
ysr@777:       // we now want to allow clearing of the marking bitmap to be
ysr@777:       // suspended by a collection pause.
ysr@777:       _sts.join();
ysr@777:       _cm->clearNextBitmap();
ysr@777:       _sts.leave();
ysr@777:     }
tonyp@2011: 
tonyp@2011:     // Update the number of full collections that have been
tonyp@2011:     // completed. This will also notify the FullGCCount_lock in case a
tonyp@2011:     // Java thread is waiting for a full GC to happen (e.g., it
tonyp@2011:     // called System.gc() with +ExplicitGCInvokesConcurrent).
tonyp@2372:     _sts.join();
tonyp@2472:     g1h->increment_full_collections_completed(true /* concurrent */);
tonyp@2372:     _sts.leave();
ysr@777:   }
ysr@777:   assert(_should_terminate, "just checking");
ysr@777: 
ysr@777:   terminate();
ysr@777: }
ysr@777: 
ysr@777: 
ysr@777: void ConcurrentMarkThread::yield() {
ysr@777:   _sts.yield("Concurrent Mark");
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentMarkThread::stop() {
ysr@777:   // it is ok to take late safepoints here, if needed
ysr@777:   MutexLockerEx mu(Terminator_lock);
ysr@777:   _should_terminate = true;
ysr@777:   while (!_has_terminated) {
ysr@777:     Terminator_lock->wait();
ysr@777:   }
ysr@777: }
ysr@777: 
tonyp@1454: void ConcurrentMarkThread::print() const {
tonyp@1454:   print_on(tty);
tonyp@1454: }
tonyp@1454: 
tonyp@1454: void ConcurrentMarkThread::print_on(outputStream* st) const {
tonyp@1454:   st->print("\"G1 Main Concurrent Mark GC Thread\" ");
tonyp@1454:   Thread::print_on(st);
tonyp@1454:   st->cr();
ysr@777: }
ysr@777: 
ysr@777: void ConcurrentMarkThread::sleepBeforeNextCycle() {
ysr@777:   // We join here because we don't want to do the "shouldConcurrentMark()"
ysr@777:   // below while the world is otherwise stopped.
johnc@2195:   assert(!in_progress(), "should have been cleared");
johnc@2195: 
ysr@777:   MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);
ysr@777:   while (!started()) {
ysr@777:     CGC_lock->wait(Mutex::_no_safepoint_check_flag);
ysr@777:   }
ysr@777:   set_in_progress();
ysr@777:   clear_started();
ysr@777: }
ysr@777: 
ysr@777: // Note: this method, although exported by the ConcurrentMarkSweepThread,
ysr@777: // which is a non-JavaThread, can only be called by a JavaThread.
ysr@777: // Currently this is done at vm creation time (post-vm-init) by the
ysr@777: // main/Primordial (Java)Thread.
ysr@777: // XXX Consider changing this in the future to allow the CMS thread
ysr@777: // itself to create this thread?
ysr@777: void ConcurrentMarkThread::makeSurrogateLockerThread(TRAPS) {
ysr@777:   assert(_slt == NULL, "SLT already created");
ysr@777:   _slt = SurrogateLockerThread::make(THREAD);
ysr@777: }