1 /*
2 * Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHUTILS_HPP
27 #define SHARE_GC_SHENANDOAH_SHENANDOAHUTILS_HPP
28
29 #include "gc/shared/gcCause.hpp"
30 #include "gc/shared/gcTraceTime.inline.hpp"
31 #include "gc/shared/gcVMOperations.hpp"
32 #include "gc/shared/isGCActiveMark.hpp"
33 #include "gc/shared/suspendibleThreadSet.hpp"
34 #include "gc/shared/workerThread.hpp"
35 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
36 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
37 #include "jfr/jfrEvents.hpp"
38 #include "memory/allocation.hpp"
39 #include "runtime/safepoint.hpp"
40 #include "runtime/vmOperations.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "services/memoryService.hpp"
43
44 #include <cmath>
45 #include <limits>
46
47 class GCTimer;
48 class ShenandoahGeneration;
49
50 #define SHENANDOAH_RETURN_EVENT_MESSAGE(generation_type, prefix, postfix) \
51 switch (generation_type) { \
52 case NON_GEN: \
53 return prefix postfix; \
54 case GLOBAL: \
55 return prefix " (Global)" postfix; \
56 case YOUNG: \
57 return prefix " (Young)" postfix; \
58 case OLD: \
59 return prefix " (Old)" postfix; \
60 default: \
61 ShouldNotReachHere(); \
62 return prefix " (Unknown)" postfix; \
63 } \
64
65 class ShenandoahGCSession : public StackObj {
66 private:
67 ShenandoahHeap* const _heap;
68 ShenandoahGeneration* const _generation;
69 GCTimer* const _timer;
70 GCTracer* const _tracer;
71
72 TraceMemoryManagerStats _trace_cycle;
73
74 static const char* cycle_end_message(ShenandoahGenerationType type);
75 public:
76 ShenandoahGCSession(GCCause::Cause cause, ShenandoahGeneration* generation,
77 bool is_degenerated = false, bool is_out_of_cycle = false);
78 ~ShenandoahGCSession();
79 };
80
81 /*
82 * ShenandoahGCPhaseTiming tracks Shenandoah specific timing information
83 * of a GC phase
84 */
85 class ShenandoahTimingsTracker : public StackObj {
86 private:
87 static ShenandoahPhaseTimings::Phase _current_phase;
88
89 ShenandoahPhaseTimings* const _timings;
90 const ShenandoahPhaseTimings::Phase _phase;
91 const bool _should_aggregate;
92 ShenandoahPhaseTimings::Phase _parent_phase;
93 double _start;
94
95 public:
96 ShenandoahTimingsTracker(ShenandoahPhaseTimings::Phase phase, bool should_aggregate = false);
97 ~ShenandoahTimingsTracker();
98
99 static ShenandoahPhaseTimings::Phase current_phase() { return _current_phase; }
100
101 static bool is_current_phase_valid();
102 };
103
104 /*
105 * ShenandoahPausePhase tracks a STW pause and emits Shenandoah timing and
106 * a corresponding JFR event
107 */
108 class ShenandoahPausePhase : public ShenandoahTimingsTracker {
109 private:
110 GCTraceTimeWrapper<LogLevel::Info, LOG_TAGS(gc)> _tracer;
111 ConcurrentGCTimer* const _timer;
112
113 public:
114 ShenandoahPausePhase(const char* title, ShenandoahPhaseTimings::Phase phase, bool log_heap_usage = false);
115 ~ShenandoahPausePhase();
116 };
117
118 /*
119 * ShenandoahConcurrentPhase tracks a concurrent GC phase and emits Shenandoah timing and
120 * a corresponding JFR event
121 */
122 class ShenandoahConcurrentPhase : public ShenandoahTimingsTracker {
123 private:
124 GCTraceTimeWrapper<LogLevel::Info, LOG_TAGS(gc)> _tracer;
125 ConcurrentGCTimer* const _timer;
126
127 public:
128 ShenandoahConcurrentPhase(const char* title, ShenandoahPhaseTimings::Phase phase, bool log_heap_usage = false);
129 ~ShenandoahConcurrentPhase();
130 };
131
132 /*
133 * ShenandoahGCPhase tracks Shenandoah specific timing information
134 * and emits a corresponding JFR event of a GC phase
135 */
136 class ShenandoahGCPhase : public ShenandoahTimingsTracker {
137 private:
138 ConcurrentGCTimer* const _timer;
139
140 public:
141 ShenandoahGCPhase(ShenandoahPhaseTimings::Phase phase);
142 ~ShenandoahGCPhase();
143 };
144
145 class ShenandoahGCWorkerPhase : public StackObj {
146 private:
147 ShenandoahPhaseTimings* const _timings;
148 const ShenandoahPhaseTimings::Phase _phase;
149 public:
150 ShenandoahGCWorkerPhase(ShenandoahPhaseTimings::Phase phase);
151 ~ShenandoahGCWorkerPhase();
152 };
153
154 // Aggregates all the things that should happen before/after the pause.
155 class ShenandoahGCPauseMark : public StackObj {
156 private:
157 ShenandoahHeap* const _heap;
158 const GCIdMark _gc_id_mark;
159 const SvcGCMarker _svc_gc_mark;
160 const IsSTWGCActiveMark _is_gc_active_mark;
161 TraceMemoryManagerStats _trace_pause;
162
163 public:
164 ShenandoahGCPauseMark(uint gc_id, const char* notification_action, SvcGCMarker::reason_type type);
165 };
166
167 class ShenandoahSafepoint : public AllStatic {
168 public:
169 // Check if Shenandoah GC safepoint is in progress. This is nominally
170 // equivalent to calling SafepointSynchronize::is_at_safepoint(), but
171 // it also checks the Shenandoah specifics, when it can.
172 static inline bool is_at_shenandoah_safepoint() {
173 if (!SafepointSynchronize::is_at_safepoint()) return false;
174
175 Thread* const thr = Thread::current();
176 // Shenandoah GC specific safepoints are scheduled by control thread.
177 // So if we are enter here from control thread, then we are definitely not
178 // at Shenandoah safepoint, but at something else.
179 if (thr == ShenandoahHeap::heap()->control_thread()) return false;
180
181 // This is not VM thread, cannot see what VM thread is doing,
182 // so pretend this is a proper Shenandoah safepoint
183 if (!thr->is_VM_thread()) return true;
184
185 // Otherwise check we are at proper operation type
186 VM_Operation* vm_op = VMThread::vm_operation();
187 if (vm_op == nullptr) return false;
188
189 VM_Operation::VMOp_Type type = vm_op->type();
190 return type == VM_Operation::VMOp_ShenandoahInitMark ||
191 type == VM_Operation::VMOp_ShenandoahFinalMarkStartEvac ||
192 type == VM_Operation::VMOp_ShenandoahFinalRoots ||
193 type == VM_Operation::VMOp_ShenandoahInitUpdateRefs ||
194 type == VM_Operation::VMOp_ShenandoahFinalUpdateRefs ||
195 type == VM_Operation::VMOp_ShenandoahFinalVerify ||
196 type == VM_Operation::VMOp_ShenandoahFullGC ||
197 type == VM_Operation::VMOp_ShenandoahDegeneratedGC;
198 }
199 };
200
201 class ShenandoahWorkerSession : public StackObj {
202 protected:
203 ShenandoahWorkerSession(uint worker_id);
204 public:
205 static inline uint worker_id() {
206 return WorkerThread::worker_id();
207 }
208 };
209
210 class ShenandoahConcurrentWorkerSession : public ShenandoahWorkerSession {
211 private:
212 EventGCPhaseConcurrent _event;
213
214 public:
215 ShenandoahConcurrentWorkerSession(uint worker_id) : ShenandoahWorkerSession(worker_id) { }
216 ~ShenandoahConcurrentWorkerSession();
217 };
218
219 class ShenandoahParallelWorkerSession : public ShenandoahWorkerSession {
220 private:
221 EventGCPhaseParallel _event;
222
223 public:
224 ShenandoahParallelWorkerSession(uint worker_id) : ShenandoahWorkerSession(worker_id) { }
225 ~ShenandoahParallelWorkerSession();
226 };
227
228 // Regions cannot be uncommitted when concurrent reset is zeroing out the bitmaps.
229 // This CADR class enforces this by forbidding region uncommits while it is in scope.
230 class ShenandoahNoUncommitMark : public StackObj {
231 ShenandoahHeap* const _heap;
232 public:
233 explicit ShenandoahNoUncommitMark(ShenandoahHeap* heap) : _heap(heap) {
234 _heap->forbid_uncommit();
235 }
236
237 ~ShenandoahNoUncommitMark() {
238 _heap->allow_uncommit();
239 }
240 };
241
242 // Casting a double that cannot be represented as a size_t may result in undefined behavior.
243 // This small function checks if the given double is representable in a size_t and returns
244 // that representation if it is. Otherwise, if the double cannot be safely cast to a size_t
245 // it returns zero.
246 inline size_t shenandoah_safe_size_cast(const double d) {
247 static constexpr double size_max_as_double = static_cast<double>(std::numeric_limits<size_t>::max());
248 if (std::isnan(d) || d < 0 || d >= size_max_as_double) {
249 // NaN is unordered, all comparisons will be false.
250 // +Inf is always greater than, -Inf is always less than
251 return 0;
252 }
253 return static_cast<size_t>(d);
254 }
255
256
257
258 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHUTILS_HPP