ysr@777: /*
brutisso@3456:  * Copyright (c) 2001, 2012, 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"
stefank@2314: #include "gc_implementation/g1/vm_operations_g1.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: 
tonyp@2315: VM_G1CollectForAllocation::VM_G1CollectForAllocation(
tonyp@2315:                                                   unsigned int gc_count_before,
tonyp@2315:                                                   size_t word_size)
tonyp@2315:   : VM_G1OperationWithAllocRequest(gc_count_before, word_size) {
tonyp@2315:   guarantee(word_size > 0, "an allocation should always be requested");
tonyp@2315: }
tonyp@2315: 
ysr@777: void VM_G1CollectForAllocation::doit() {
ysr@777:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
tonyp@2315:   _result = g1h->satisfy_failed_allocation(_word_size, &_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: 
tonyp@2315: VM_G1IncCollectionPause::VM_G1IncCollectionPause(
tonyp@2315:                                       unsigned int   gc_count_before,
tonyp@2315:                                       size_t         word_size,
tonyp@2315:                                       bool           should_initiate_conc_mark,
tonyp@2315:                                       double         target_pause_time_ms,
tonyp@2315:                                       GCCause::Cause gc_cause)
tonyp@2315:   : VM_G1OperationWithAllocRequest(gc_count_before, word_size),
tonyp@2315:     _should_initiate_conc_mark(should_initiate_conc_mark),
tonyp@2315:     _target_pause_time_ms(target_pause_time_ms),
tonyp@2315:     _full_collections_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:   guarantee(word_size == 0 || gc_cause == GCCause::_g1_inc_collection_pause,
tonyp@2315:             "we can only request an allocation if the GC cause is for "
tonyp@2315:             "an incremental GC pause");
tonyp@2315:   _gc_cause = gc_cause;
tonyp@2315: }
tonyp@2315: 
ysr@777: void VM_G1IncCollectionPause::doit() {
ysr@777:   G1CollectedHeap* g1h = G1CollectedHeap::heap();
tonyp@2011:   assert(!_should_initiate_conc_mark ||
tonyp@2011:   ((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
brutisso@3456:    (_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent) ||
brutisso@3456:     _gc_cause == GCCause::_g1_humongous_allocation),
brutisso@3456:          "only a GC locker, a System.gc() 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.
tonyp@2315:     _result = g1h->attempt_allocation_at_safepoint(_word_size,
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) {
tonyp@2011:     // It's safer to read full_collections_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.
tonyp@2011:     _full_collections_completed_before = g1h->full_collections_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@2970:     // If a marking cycle is already in progress just return and skip
johnc@2970:     // the pause - the requesting thread should block in doit_epilogue
johnc@2970:     // until the marking cycle is complete.
johnc@2970:     if (!res) {
johnc@2970:       assert(_word_size == 0, "ExplicitGCInvokesConcurrent shouldn't be allocating");
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.
tonyp@2315:     _result = g1h->attempt_allocation_at_safepoint(_word_size,
tonyp@2315:                                       true /* expect_null_cur_alloc_region */);
tonyp@2315:   } else {
tonyp@2315:     assert(_result == NULL, "invariant");
tonyp@2315:   }
tonyp@2011: }
tonyp@2011: 
tonyp@2011: void VM_G1IncCollectionPause::doit_epilogue() {
tonyp@2011:   VM_GC_Operation::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: 
tonyp@2011:     // In the doit() method we saved g1h->full_collections_completed()
tonyp@2011:     // in the _full_collections_completed_before field. We have to
tonyp@2011:     // wait until we observe that g1h->full_collections_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.
tonyp@2011:     if (g1h->full_collections_completed() <=
tonyp@2011:                                           _full_collections_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);
tonyp@2011:       while (g1h->full_collections_completed() <=
tonyp@2011:                                           _full_collections_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@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::acquirePLL);
johnc@3218: }
johnc@3218: 
johnc@3218: void VM_CGC_Operation::release_and_notify_pending_list_lock() {
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() {
ysr@777:   gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
ysr@777:   TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
ysr@777:   TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
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@3218:   acquire_pending_list_lock();
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@3218:   release_and_notify_pending_list_lock();
ysr@777: }