ysr@777: /*
mlarsson@7686:  * Copyright (c) 2001, 2015, 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"
johnc@3218: #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
stefank@2314: #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
stefank@2314: #include "gc_implementation/g1/g1CollectorPolicy.hpp"
brutisso@3710: #include "gc_implementation/g1/g1Log.hpp"
stefank@2314: #include "gc_implementation/g1/vm_operations_g1.hpp"
sla@5237: #include "gc_implementation/shared/gcTimer.hpp"
sla@5237: #include "gc_implementation/shared/gcTraceTime.hpp"
stefank@2314: #include "gc_implementation/shared/isGCActiveMark.hpp"
tonyp@2315: #include "gc_implementation/g1/vm_operations_g1.hpp"
stefank@2314: #include "runtime/interfaceSupport.hpp"
ysr@777: 
mlarsson@7686: VM_G1CollectForAllocation::VM_G1CollectForAllocation(uint gc_count_before,
mlarsson@7686:                                                      size_t word_size)
johnc@3666:   : VM_G1OperationWithAllocRequest(gc_count_before, word_size,
johnc@3666:                                    GCCause::_allocation_failure) {
mlarsson@7687:   guarantee(word_size != 0, "An allocation should always be requested with this operation.");
tonyp@2315: }
tonyp@2315: 
ysr@777: void VM_G1CollectForAllocation::doit() {
ysr@777:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
johnc@3765:   GCCauseSetter x(g1h, _gc_cause);
sjohanss@7118: 
sjohanss@7118:   _result = g1h->satisfy_failed_allocation(_word_size, allocation_context(), &_pause_succeeded);
tonyp@2315:   assert(_result == NULL || _pause_succeeded,
tonyp@2315:          "if we get back a result, the pause should have succeeded");
ysr@777: }
ysr@777: 
ysr@777: void VM_G1CollectFull::doit() {
ysr@777:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
ysr@777:   GCCauseSetter x(g1h, _gc_cause);
ysr@777:   g1h->do_full_collection(false /* clear_all_soft_refs */);
ysr@777: }
ysr@777: 
mlarsson@7686: VM_G1IncCollectionPause::VM_G1IncCollectionPause(uint           gc_count_before,
mlarsson@7686:                                                  size_t         word_size,
mlarsson@7686:                                                  bool           should_initiate_conc_mark,
mlarsson@7686:                                                  double         target_pause_time_ms,
mlarsson@7686:                                                  GCCause::Cause gc_cause)
johnc@3666:   : VM_G1OperationWithAllocRequest(gc_count_before, word_size, gc_cause),
tonyp@2315:     _should_initiate_conc_mark(should_initiate_conc_mark),
tonyp@2315:     _target_pause_time_ms(target_pause_time_ms),
johnc@3666:     _should_retry_gc(false),
brutisso@3823:     _old_marking_cycles_completed_before(0) {
tonyp@2315:   guarantee(target_pause_time_ms > 0.0,
tonyp@2315:             err_msg("target_pause_time_ms = %1.6lf should be positive",
tonyp@2315:                     target_pause_time_ms));
tonyp@2315:   _gc_cause = gc_cause;
tonyp@2315: }
tonyp@2315: 
johnc@3666: bool VM_G1IncCollectionPause::doit_prologue() {
mlarsson@7687:   bool res = VM_G1OperationWithAllocRequest::doit_prologue();
johnc@3666:   if (!res) {
johnc@3666:     if (_should_initiate_conc_mark) {
johnc@3666:       // The prologue can fail for a couple of reasons. The first is that another GC
johnc@3666:       // got scheduled and prevented the scheduling of the initial mark GC. The
johnc@3666:       // second is that the GC locker may be active and the heap can't be expanded.
johnc@3666:       // In both cases we want to retry the GC so that the initial mark pause is
johnc@3666:       // actually scheduled. In the second case, however, we should stall until
johnc@3666:       // until the GC locker is no longer active and then retry the initial mark GC.
johnc@3666:       _should_retry_gc = true;
johnc@3666:     }
johnc@3666:   }
johnc@3666:   return res;
johnc@3666: }
johnc@3666: 
ysr@777: void VM_G1IncCollectionPause::doit() {
ysr@777:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
kevinw@8194:   assert(!_should_initiate_conc_mark || g1h->should_do_concurrent_full_gc(_gc_cause),
kevinw@8194:       "only a GC locker, a System.gc(), stats update, whitebox, or a hum allocation induced GC should start a cycle");
tonyp@2011: 
tonyp@2315:   if (_word_size > 0) {
tonyp@2315:     // An allocation has been requested. So, try to do that first.
sjohanss@7118:     _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
tonyp@2315:                                      false /* expect_null_cur_alloc_region */);
tonyp@2315:     if (_result != NULL) {
tonyp@2315:       // If we can successfully allocate before we actually do the
tonyp@2315:       // pause then we will consider this pause successful.
tonyp@2315:       _pause_succeeded = true;
tonyp@2315:       return;
tonyp@2315:     }
tonyp@2315:   }
tonyp@2315: 
ysr@1523:   GCCauseSetter x(g1h, _gc_cause);
tonyp@2011:   if (_should_initiate_conc_mark) {
brutisso@3823:     // It's safer to read old_marking_cycles_completed() here, given
tonyp@2011:     // that noone else will be updating it concurrently. Since we'll
tonyp@2011:     // only need it if we're initiating a marking cycle, no point in
tonyp@2011:     // setting it earlier.
brutisso@3823:     _old_marking_cycles_completed_before = g1h->old_marking_cycles_completed();
tonyp@2011: 
tonyp@2011:     // At this point we are supposed to start a concurrent cycle. We
tonyp@2011:     // will do so if one is not already in progress.
tonyp@3114:     bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);
johnc@2970: 
johnc@2970:     // The above routine returns true if we were able to force the
johnc@2970:     // next GC pause to be an initial mark; it returns false if a
johnc@2970:     // marking cycle is already in progress.
johnc@2970:     //
johnc@3666:     // If a marking cycle is already in progress just return and skip the
johnc@3666:     // pause below - if the reason for requesting this initial mark pause
johnc@3666:     // was due to a System.gc() then the requesting thread should block in
johnc@3666:     // doit_epilogue() until the marking cycle is complete.
johnc@3666:     //
johnc@3666:     // If this initial mark pause was requested as part of a humongous
johnc@3666:     // allocation then we know that the marking cycle must just have
johnc@3666:     // been started by another thread (possibly also allocating a humongous
johnc@3666:     // object) as there was no active marking cycle when the requesting
johnc@3666:     // thread checked before calling collect() in
johnc@3666:     // attempt_allocation_humongous(). Retrying the GC, in this case,
johnc@3666:     // will cause the requesting thread to spin inside collect() until the
johnc@3666:     // just started marking cycle is complete - which may be a while. So
johnc@3666:     // we do NOT retry the GC.
johnc@2970:     if (!res) {
johnc@3666:       assert(_word_size == 0, "Concurrent Full GC/Humongous Object IM shouldn't be allocating");
johnc@3666:       if (_gc_cause != GCCause::_g1_humongous_allocation) {
johnc@3666:         _should_retry_gc = true;
johnc@3666:       }
johnc@2970:       return;
johnc@2970:     }
tonyp@2011:   }
tonyp@2315: 
tonyp@2315:   _pause_succeeded =
tonyp@2315:     g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
tonyp@2315:   if (_pause_succeeded && _word_size > 0) {
tonyp@2315:     // An allocation had been requested.
sjohanss@7118:     _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
tonyp@2315:                                       true /* expect_null_cur_alloc_region */);
tonyp@2315:   } else {
tonyp@2315:     assert(_result == NULL, "invariant");
johnc@3666:     if (!_pause_succeeded) {
johnc@3666:       // Another possible reason reason for the pause to not be successful
johnc@3666:       // is that, again, the GC locker is active (and has become active
johnc@3666:       // since the prologue was executed). In this case we should retry
johnc@3666:       // the pause after waiting for the GC locker to become inactive.
johnc@3666:       _should_retry_gc = true;
johnc@3666:     }
tonyp@2315:   }
tonyp@2011: }
tonyp@2011: 
tonyp@2011: void VM_G1IncCollectionPause::doit_epilogue() {
mlarsson@7687:   VM_G1OperationWithAllocRequest::doit_epilogue();
tonyp@2011: 
tonyp@2011:   // If the pause was initiated by a System.gc() and
tonyp@2011:   // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
tonyp@2011:   // that just started (or maybe one that was already in progress) to
tonyp@2011:   // finish.
tonyp@2011:   if (_gc_cause == GCCause::_java_lang_system_gc &&
tonyp@2011:       _should_initiate_conc_mark) {
tonyp@2011:     assert(ExplicitGCInvokesConcurrent,
tonyp@2011:            "the only way to be here is if ExplicitGCInvokesConcurrent is set");
tonyp@2011: 
tonyp@2011:     G1CollectedHeap* g1h = G1CollectedHeap::heap();
tonyp@2011: 
brutisso@3823:     // In the doit() method we saved g1h->old_marking_cycles_completed()
brutisso@3823:     // in the _old_marking_cycles_completed_before field. We have to
brutisso@3823:     // wait until we observe that g1h->old_marking_cycles_completed()
tonyp@2011:     // has increased by at least one. This can happen if a) we started
tonyp@2011:     // a cycle and it completes, b) a cycle already in progress
tonyp@2011:     // completes, or c) a Full GC happens.
tonyp@2011: 
tonyp@2011:     // If the condition has already been reached, there's no point in
tonyp@2011:     // actually taking the lock and doing the wait.
brutisso@3823:     if (g1h->old_marking_cycles_completed() <=
brutisso@3823:                                           _old_marking_cycles_completed_before) {
tonyp@2011:       // The following is largely copied from CMS
tonyp@2011: 
tonyp@2011:       Thread* thr = Thread::current();
tonyp@2011:       assert(thr->is_Java_thread(), "invariant");
tonyp@2011:       JavaThread* jt = (JavaThread*)thr;
tonyp@2011:       ThreadToNativeFromVM native(jt);
tonyp@2011: 
tonyp@2011:       MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
brutisso@3823:       while (g1h->old_marking_cycles_completed() <=
brutisso@3823:                                           _old_marking_cycles_completed_before) {
tonyp@2011:         FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
tonyp@2011:       }
tonyp@2011:     }
tonyp@2011:   }
ysr@777: }
ysr@777: 
johnc@3218: void VM_CGC_Operation::acquire_pending_list_lock() {
johnc@3666:   assert(_needs_pll, "don't call this otherwise");
johnc@3218:   // The caller may block while communicating
johnc@3218:   // with the SLT thread in order to acquire/release the PLL.
kbarrett@7360:   SurrogateLockerThread* slt = ConcurrentMarkThread::slt();
kbarrett@7360:   if (slt != NULL) {
kbarrett@7360:     slt->manipulatePLL(SurrogateLockerThread::acquirePLL);
kbarrett@7360:   } else {
kbarrett@7360:     SurrogateLockerThread::report_missing_slt();
kbarrett@7360:   }
johnc@3218: }
johnc@3218: 
johnc@3218: void VM_CGC_Operation::release_and_notify_pending_list_lock() {
johnc@3666:   assert(_needs_pll, "don't call this otherwise");
johnc@3218:   // The caller may block while communicating
johnc@3218:   // with the SLT thread in order to acquire/release the PLL.
johnc@3218:   ConcurrentMarkThread::slt()->
johnc@3218:     manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
johnc@3218: }
johnc@3218: 
ysr@777: void VM_CGC_Operation::doit() {
brutisso@3710:   TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
brutisso@6904:   GCTraceTime t(_printGCMessage, G1Log::fine(), true, G1CollectedHeap::heap()->gc_timer_cm(), G1CollectedHeap::heap()->concurrent_mark()->concurrent_gc_id());
ysr@777:   SharedHeap* sh = SharedHeap::heap();
ysr@777:   // This could go away if CollectedHeap gave access to _gc_is_active...
ysr@777:   if (sh != NULL) {
ysr@777:     IsGCActiveMark x;
ysr@777:     _cl->do_void();
ysr@777:   } else {
ysr@777:     _cl->do_void();
ysr@777:   }
ysr@777: }
ysr@777: 
ysr@777: bool VM_CGC_Operation::doit_prologue() {
johnc@3218:   // Note the relative order of the locks must match that in
johnc@3218:   // VM_GC_Operation::doit_prologue() or deadlocks can occur
johnc@3666:   if (_needs_pll) {
johnc@3666:     acquire_pending_list_lock();
johnc@3666:   }
johnc@3218: 
ysr@777:   Heap_lock->lock();
ysr@777:   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
ysr@777:   return true;
ysr@777: }
ysr@777: 
ysr@777: void VM_CGC_Operation::doit_epilogue() {
johnc@3218:   // Note the relative order of the unlocks must match that in
johnc@3218:   // VM_GC_Operation::doit_epilogue()
ysr@777:   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
ysr@777:   Heap_lock->unlock();
johnc@3666:   if (_needs_pll) {
johnc@3666:     release_and_notify_pending_list_lock();
johnc@3666:   }
ysr@777: }