1 /*
2 * Copyright (c) 1997, 2019, 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/shared/collectedHeap.hpp"
27 #include "gc/shared/collectedHeap.inline.hpp"
28 #include "logging/log.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "memory/universe.hpp"
31 #include "runtime/atomic.hpp"
32 #include "runtime/frame.inline.hpp"
33 #include "runtime/handles.inline.hpp"
34 #include "runtime/init.hpp"
35 #include "runtime/interfaceSupport.inline.hpp"
36 #include "runtime/orderAccess.hpp"
37 #include "runtime/os.inline.hpp"
38 #include "runtime/thread.inline.hpp"
39 #include "runtime/safepointVerifiers.hpp"
40 #include "runtime/vframe.hpp"
41 #include "runtime/vmThread.hpp"
42 #include "utilities/preserveException.hpp"
43
44 // Implementation of InterfaceSupport
45
46 #ifdef ASSERT
47 VMEntryWrapper::VMEntryWrapper() {
48 if (VerifyLastFrame) {
49 InterfaceSupport::verify_last_frame();
50 }
51 }
52
53 VMEntryWrapper::~VMEntryWrapper() {
54 InterfaceSupport::check_gc_alot();
55 if (WalkStackALot) {
56 InterfaceSupport::walk_stack();
57 }
58 if (DeoptimizeALot || DeoptimizeRandom) {
59 InterfaceSupport::deoptimizeAll();
60 }
61 if (ZombieALot) {
62 InterfaceSupport::zombieAll();
63 }
64 // do verification AFTER potential deoptimization
65 if (VerifyStack) {
66 InterfaceSupport::verify_stack();
67 }
68 }
69
70 VMNativeEntryWrapper::VMNativeEntryWrapper() {
71 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot();
72 }
73
74 VMNativeEntryWrapper::~VMNativeEntryWrapper() {
75 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot();
76 }
77
78 long InterfaceSupport::_number_of_calls = 0;
79 long InterfaceSupport::_scavenge_alot_counter = 1;
80 long InterfaceSupport::_fullgc_alot_counter = 1;
81 long InterfaceSupport::_fullgc_alot_invocation = 0;
82
83 Histogram* RuntimeHistogram;
84
85 RuntimeHistogramElement::RuntimeHistogramElement(const char* elementName) {
86 static volatile int RuntimeHistogram_lock = 0;
87 _name = elementName;
88 uintx count = 0;
89
90 while (Atomic::cmpxchg(&RuntimeHistogram_lock, 0, 1) != 0) {
91 while (Atomic::load_acquire(&RuntimeHistogram_lock) != 0) {
92 count +=1;
93 if ( (WarnOnStalledSpinLock > 0)
94 && (count % WarnOnStalledSpinLock == 0)) {
95 warning("RuntimeHistogram_lock seems to be stalled");
96 }
97 }
98 }
99
100 if (RuntimeHistogram == NULL) {
101 RuntimeHistogram = new Histogram("VM Runtime Call Counts",200);
102 }
103
104 RuntimeHistogram->add_element(this);
105 Atomic::dec(&RuntimeHistogram_lock);
106 }
107
108 void InterfaceSupport::gc_alot() {
109 Thread *thread = Thread::current();
110 if (!thread->is_Java_thread()) return; // Avoid concurrent calls
111 // Check for new, not quite initialized thread. A thread in new mode cannot initiate a GC.
112 JavaThread *current_thread = (JavaThread *)thread;
113 if (current_thread->active_handles() == NULL) return;
114
115 // Short-circuit any possible re-entrant gc-a-lot attempt
116 if (thread->skip_gcalot()) return;
117
118 if (Threads::is_vm_complete()) {
119
120 if (++_fullgc_alot_invocation < FullGCALotStart) {
121 return;
122 }
123
124 // Use this line if you want to block at a specific point,
125 // e.g. one number_of_calls/scavenge/gc before you got into problems
126 if (FullGCALot) _fullgc_alot_counter--;
127
128 // Check if we should force a full gc
129 if (_fullgc_alot_counter == 0) {
130 // Release dummy so objects are forced to move
131 if (!Universe::release_fullgc_alot_dummy()) {
132 warning("FullGCALot: Unable to release more dummies at bottom of heap");
133 }
134 HandleMark hm(thread);
135 Universe::heap()->collect(GCCause::_full_gc_alot);
136 unsigned int invocations = Universe::heap()->total_full_collections();
137 // Compute new interval
138 if (FullGCALotInterval > 1) {
139 _fullgc_alot_counter = 1+(long)((double)FullGCALotInterval*os::random()/(max_jint+1.0));
140 log_trace(gc)("Full gc no: %u\tInterval: %ld", invocations, _fullgc_alot_counter);
141 } else {
142 _fullgc_alot_counter = 1;
143 }
144 // Print progress message
145 if (invocations % 100 == 0) {
146 log_trace(gc)("Full gc no: %u", invocations);
147 }
148 } else {
149 if (ScavengeALot) _scavenge_alot_counter--;
150 // Check if we should force a scavenge
151 if (_scavenge_alot_counter == 0) {
152 HandleMark hm(thread);
153 Universe::heap()->collect(GCCause::_scavenge_alot);
154 unsigned int invocations = Universe::heap()->total_collections() - Universe::heap()->total_full_collections();
155 // Compute new interval
156 if (ScavengeALotInterval > 1) {
157 _scavenge_alot_counter = 1+(long)((double)ScavengeALotInterval*os::random()/(max_jint+1.0));
158 log_trace(gc)("Scavenge no: %u\tInterval: %ld", invocations, _scavenge_alot_counter);
159 } else {
160 _scavenge_alot_counter = 1;
161 }
162 // Print progress message
163 if (invocations % 1000 == 0) {
164 log_trace(gc)("Scavenge no: %u", invocations);
165 }
166 }
167 }
168 }
169 }
170
171
172 vframe* vframe_array[50];
173 int walk_stack_counter = 0;
174
175 void InterfaceSupport::walk_stack_from(vframe* start_vf) {
176 // walk
177 int i = 0;
178 for (vframe* f = start_vf; f; f = f->sender() ) {
179 if (i < 50) vframe_array[i++] = f;
180 }
181 }
182
183
184 void InterfaceSupport::walk_stack() {
185 JavaThread* thread = JavaThread::current();
186 walk_stack_counter++;
187 if (!thread->has_last_Java_frame()) return;
188 ResourceMark rm(thread);
189 RegisterMap reg_map(thread);
190 walk_stack_from(thread->last_java_vframe(®_map));
191 }
192
193 // invocation counter for InterfaceSupport::deoptimizeAll/zombieAll functions
194 int deoptimizeAllCounter = 0;
195 int zombieAllCounter = 0;
196
197 void InterfaceSupport::zombieAll() {
198 // This method is called by all threads when a thread make
199 // transition to VM state (for example, runtime calls).
200 // Divide number of calls by number of threads to avoid
201 // dependence of ZombieAll events frequency on number of threads.
202 int value = zombieAllCounter / Threads::number_of_threads();
203 if (is_init_completed() && value > ZombieALotInterval) {
204 zombieAllCounter = 0;
205 VM_ZombieAll op;
206 VMThread::execute(&op);
207 }
208 zombieAllCounter++;
209 }
210
211 void InterfaceSupport::deoptimizeAll() {
212 // This method is called by all threads when a thread make
213 // transition to VM state (for example, runtime calls).
214 // Divide number of calls by number of threads to avoid
215 // dependence of DeoptimizeAll events frequency on number of threads.
216 int value = deoptimizeAllCounter / Threads::number_of_threads();
217 if (is_init_completed()) {
218 if (DeoptimizeALot && value > DeoptimizeALotInterval) {
219 deoptimizeAllCounter = 0;
220 VM_DeoptimizeAll op;
221 VMThread::execute(&op);
222 } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {
223 VM_DeoptimizeAll op;
224 VMThread::execute(&op);
225 }
226 }
227 deoptimizeAllCounter++;
228 }
229
230
231 void InterfaceSupport::verify_stack() {
232 JavaThread* thread = JavaThread::current();
233 ResourceMark rm(thread);
234 // disabled because it throws warnings that oop maps should only be accessed
235 // in VM thread or during debugging
236
237 if (!thread->has_pending_exception()) {
238 // verification does not work if there are pending exceptions
239 StackFrameStream sfs(thread);
240 CodeBlob* cb = sfs.current()->cb();
241 // In case of exceptions we might not have a runtime_stub on
242 // top of stack, hence, all callee-saved registers are not going
243 // to be setup correctly, hence, we cannot do stack verify
244 if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;
245
246 for (; !sfs.is_done(); sfs.next()) {
247 sfs.current()->verify(sfs.register_map());
248 }
249 }
250 }
251
252
253 void InterfaceSupport::verify_last_frame() {
254 JavaThread* thread = JavaThread::current();
255 ResourceMark rm(thread);
256 RegisterMap reg_map(thread);
257 frame fr = thread->last_frame();
258 fr.verify(®_map);
259 }
260
261
262 #endif // ASSERT
263
264
265 void InterfaceSupport_init() {
266 #ifdef ASSERT
267 if (ScavengeALot || FullGCALot) {
268 srand(ScavengeALotInterval * FullGCALotInterval);
269 }
270 #endif
271 }