1 /*
2 * Copyright (c) 2001, 2020, 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/g1/g1CollectedHeap.inline.hpp"
27 #include "gc/g1/g1ConcurrentMarkThread.inline.hpp"
28 #include "gc/g1/g1Policy.hpp"
29 #include "gc/g1/g1VMOperations.hpp"
30 #include "gc/shared/concurrentGCBreakpoints.hpp"
31 #include "gc/shared/gcCause.hpp"
32 #include "gc/shared/gcId.hpp"
33 #include "gc/shared/gcTimer.hpp"
34 #include "gc/shared/gcTraceTime.inline.hpp"
35 #include "gc/shared/isGCActiveMark.hpp"
36 #include "memory/universe.hpp"
37 #include "runtime/interfaceSupport.inline.hpp"
38
39 void VM_G1CollectFull::doit() {
40 G1CollectedHeap* g1h = G1CollectedHeap::heap();
41 GCCauseSetter x(g1h, _gc_cause);
42 _gc_succeeded = g1h->do_full_collection(true /* explicit_gc */, false /* clear_all_soft_refs */);
43 }
44
45 VM_G1TryInitiateConcMark::VM_G1TryInitiateConcMark(uint gc_count_before,
46 GCCause::Cause gc_cause,
47 double target_pause_time_ms) :
48 VM_GC_Operation(gc_count_before, gc_cause),
49 _target_pause_time_ms(target_pause_time_ms),
50 _transient_failure(false),
51 _cycle_already_in_progress(false),
52 _whitebox_attached(false),
53 _terminating(false),
54 _gc_succeeded(false)
55 {}
56
57 bool VM_G1TryInitiateConcMark::doit_prologue() {
58 bool result = VM_GC_Operation::doit_prologue();
59 // The prologue can fail for a couple of reasons. The first is that another GC
60 // got scheduled and prevented the scheduling of the initial mark GC. The
61 // second is that the GC locker may be active and the heap can't be expanded.
62 // In both cases we want to retry the GC so that the initial mark pause is
63 // actually scheduled. In the second case, however, we should stall until
64 // until the GC locker is no longer active and then retry the initial mark GC.
65 if (!result) _transient_failure = true;
66 return result;
67 }
68
69 void VM_G1TryInitiateConcMark::doit() {
70 G1CollectedHeap* g1h = G1CollectedHeap::heap();
71
72 GCCauseSetter x(g1h, _gc_cause);
73
74 // Record for handling by caller.
75 _terminating = g1h->_cm_thread->should_terminate();
76
77 if (_terminating && GCCause::is_user_requested_gc(_gc_cause)) {
78 // When terminating, the request to initiate a concurrent cycle will be
79 // ignored by do_collection_pause_at_safepoint; instead it will just do
80 // a young-only or mixed GC (depending on phase). For a user request
81 // there's no point in even doing that much, so done. For some non-user
82 // requests the alternative GC might still be needed.
83 } else if (!g1h->policy()->force_initial_mark_if_outside_cycle(_gc_cause)) {
84 // Failure to force the next GC pause to be an initial mark indicates
85 // there is already a concurrent marking cycle in progress. Set flag
86 // to notify the caller and return immediately.
87 _cycle_already_in_progress = true;
88 } else if ((_gc_cause != GCCause::_wb_breakpoint) &&
89 ConcurrentGCBreakpoints::is_controlled()) {
90 // WhiteBox wants to be in control of concurrent cycles, so don't try to
91 // start one. This check is after the force_initial_mark_xxx so that a
92 // request will be remembered for a later partial collection, even though
93 // we've rejected this request.
94 _whitebox_attached = true;
95 } else if (g1h->do_collection_pause_at_safepoint(_target_pause_time_ms)) {
96 _gc_succeeded = true;
97 } else {
98 // Failure to perform the collection at all occurs because GCLocker is
99 // active, and we have the bad luck to be the collection request that
100 // makes a later _gc_locker collection needed. (Else we would have hit
101 // the GCLocker check in the prologue.)
102 _transient_failure = true;
103 }
104 }
105
106 VM_G1CollectForAllocation::VM_G1CollectForAllocation(size_t word_size,
107 uint gc_count_before,
108 GCCause::Cause gc_cause,
109 double target_pause_time_ms) :
110 VM_CollectForAllocation(word_size, gc_count_before, gc_cause),
111 _gc_succeeded(false),
112 _target_pause_time_ms(target_pause_time_ms) {
113
114 guarantee(target_pause_time_ms > 0.0,
115 "target_pause_time_ms = %1.6lf should be positive",
116 target_pause_time_ms);
117 _gc_cause = gc_cause;
118 }
119
120 void VM_G1CollectForAllocation::doit() {
121 G1CollectedHeap* g1h = G1CollectedHeap::heap();
122
123 if (_word_size > 0) {
124 // An allocation has been requested. So, try to do that first.
125 _result = g1h->attempt_allocation_at_safepoint(_word_size,
126 false /* expect_null_cur_alloc_region */);
127 if (_result != NULL) {
128 // If we can successfully allocate before we actually do the
129 // pause then we will consider this pause successful.
130 _gc_succeeded = true;
131 return;
132 }
133 }
134
135 GCCauseSetter x(g1h, _gc_cause);
136 // Try a partial collection of some kind.
137 _gc_succeeded = g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
138
139 if (_gc_succeeded && (_word_size > 0)) {
140 // An allocation had been requested. Do it, eventually trying a stronger
141 // kind of GC.
142 _result = g1h->satisfy_failed_allocation(_word_size, &_gc_succeeded);
143 }
144 }
145
146 void VM_G1Concurrent::doit() {
147 GCIdMark gc_id_mark(_gc_id);
148 GCTraceCPUTime tcpu;
149 G1CollectedHeap* g1h = G1CollectedHeap::heap();
150
151 // GCTraceTime(...) only supports sub-phases, so a more verbose version
152 // is needed when we report the top-level pause phase.
153 GCTraceTimeLogger(Info, gc) logger(_message, GCCause::_no_gc, true);
154 GCTraceTimePauseTimer timer(_message, g1h->concurrent_mark()->gc_timer_cm());
155 GCTraceTimeDriver t(&logger, &timer);
156
157 TraceCollectorStats tcs(g1h->g1mm()->conc_collection_counters());
158 SvcGCMarker sgcm(SvcGCMarker::CONCURRENT);
159 IsGCActiveMark x;
160 _cl->do_void();
161 }
162
163 bool VM_G1Concurrent::doit_prologue() {
164 Heap_lock->lock();
165 return true;
166 }
167
168 void VM_G1Concurrent::doit_epilogue() {
169 if (Universe::has_reference_pending_list()) {
170 Heap_lock->notify_all();
171 }
172 Heap_lock->unlock();
173 }