1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
27 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
28 #include "gc_implementation/g1/vm_operations_g1.hpp"
29 #include "gc_implementation/shared/isGCActiveMark.hpp"
30 #include "runtime/interfaceSupport.hpp"
31
32 void VM_G1CollectForAllocation::doit() {
33 JvmtiGCForAllocationMarker jgcm;
34 G1CollectedHeap* g1h = G1CollectedHeap::heap();
35 _res = g1h->satisfy_failed_allocation(_size);
36 assert(g1h->is_in_or_null(_res), "result not in heap");
37 }
38
39 void VM_G1CollectFull::doit() {
40 JvmtiGCFullMarker jgcm;
41 G1CollectedHeap* g1h = G1CollectedHeap::heap();
42 GCCauseSetter x(g1h, _gc_cause);
43 g1h->do_full_collection(false /* clear_all_soft_refs */);
44 }
45
46 void VM_G1IncCollectionPause::doit() {
47 JvmtiGCForAllocationMarker jgcm;
48 G1CollectedHeap* g1h = G1CollectedHeap::heap();
49 assert(!_should_initiate_conc_mark ||
50 ((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
51 (_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)),
52 "only a GC locker or a System.gc() induced GC should start a cycle");
53
54 GCCauseSetter x(g1h, _gc_cause);
55 if (_should_initiate_conc_mark) {
56 // It's safer to read full_collections_completed() here, given
57 // that noone else will be updating it concurrently. Since we'll
58 // only need it if we're initiating a marking cycle, no point in
59 // setting it earlier.
60 _full_collections_completed_before = g1h->full_collections_completed();
61
62 // At this point we are supposed to start a concurrent cycle. We
63 // will do so if one is not already in progress.
64 bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle();
65 }
66 g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
67 }
68
69 void VM_G1IncCollectionPause::doit_epilogue() {
70 VM_GC_Operation::doit_epilogue();
71
72 // If the pause was initiated by a System.gc() and
73 // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
74 // that just started (or maybe one that was already in progress) to
75 // finish.
76 if (_gc_cause == GCCause::_java_lang_system_gc &&
77 _should_initiate_conc_mark) {
78 assert(ExplicitGCInvokesConcurrent,
79 "the only way to be here is if ExplicitGCInvokesConcurrent is set");
80
81 G1CollectedHeap* g1h = G1CollectedHeap::heap();
82
83 // In the doit() method we saved g1h->full_collections_completed()
84 // in the _full_collections_completed_before field. We have to
85 // wait until we observe that g1h->full_collections_completed()
86 // has increased by at least one. This can happen if a) we started
87 // a cycle and it completes, b) a cycle already in progress
88 // completes, or c) a Full GC happens.
89
90 // If the condition has already been reached, there's no point in
91 // actually taking the lock and doing the wait.
92 if (g1h->full_collections_completed() <=
93 _full_collections_completed_before) {
94 // The following is largely copied from CMS
95
96 Thread* thr = Thread::current();
97 assert(thr->is_Java_thread(), "invariant");
98 JavaThread* jt = (JavaThread*)thr;
99 ThreadToNativeFromVM native(jt);
100
101 MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
102 while (g1h->full_collections_completed() <=
103 _full_collections_completed_before) {
104 FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
105 }
106 }
107 }
108 }
109
110 void VM_CGC_Operation::doit() {
111 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
112 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
113 TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
114 SharedHeap* sh = SharedHeap::heap();
115 // This could go away if CollectedHeap gave access to _gc_is_active...
116 if (sh != NULL) {
117 IsGCActiveMark x;
118 _cl->do_void();
119 } else {
120 _cl->do_void();
121 }
122 }
123
124 bool VM_CGC_Operation::doit_prologue() {
125 Heap_lock->lock();
126 SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
127 return true;
128 }
129
130 void VM_CGC_Operation::doit_epilogue() {
131 SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
132 Heap_lock->unlock();
133 }