1 /*
2 * Copyright (c) 1997, 2016, 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 "gc/shared/genCollectedHeap.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "runtime/atomic.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/init.hpp"
33 #include "runtime/interfaceSupport.inline.hpp"
34 #include "runtime/orderAccess.inline.hpp"
35 #include "runtime/os.inline.hpp"
36 #include "runtime/thread.inline.hpp"
37 #include "runtime/vframe.hpp"
38 #include "utilities/preserveException.hpp"
39
40 // Implementation of InterfaceSupport
41
42 #ifdef ASSERT
43 VMEntryWrapper::VMEntryWrapper() {
44 if (VerifyLastFrame) {
45 InterfaceSupport::verify_last_frame();
46 }
47 }
48
49 VMEntryWrapper::~VMEntryWrapper() {
50 InterfaceSupport::check_gc_alot();
51 if (WalkStackALot) {
52 InterfaceSupport::walk_stack();
53 }
54 #ifdef COMPILER2
55 // This option is not used by Compiler 1
56 if (StressDerivedPointers) {
57 InterfaceSupport::stress_derived_pointers();
58 }
59 #endif
60 if (DeoptimizeALot || DeoptimizeRandom) {
61 InterfaceSupport::deoptimizeAll();
62 }
63 if (ZombieALot) {
64 InterfaceSupport::zombieAll();
65 }
66 if (UnlinkSymbolsALot) {
67 InterfaceSupport::unlinkSymbols();
68 }
69 // do verification AFTER potential deoptimization
70 if (VerifyStack) {
71 InterfaceSupport::verify_stack();
72 }
73 }
74
75 long InterfaceSupport::_number_of_calls = 0;
76 long InterfaceSupport::_scavenge_alot_counter = 1;
77 long InterfaceSupport::_fullgc_alot_counter = 1;
78 long InterfaceSupport::_fullgc_alot_invocation = 0;
79
80 Histogram* RuntimeHistogram;
81
82 RuntimeHistogramElement::RuntimeHistogramElement(const char* elementName) {
83 static volatile int RuntimeHistogram_lock = 0;
84 _name = elementName;
85 uintx count = 0;
86
87 while (Atomic::cmpxchg(1, &RuntimeHistogram_lock, 0) != 0) {
88 while (OrderAccess::load_acquire(&RuntimeHistogram_lock) != 0) {
89 count +=1;
90 if ( (WarnOnStalledSpinLock > 0)
91 && (count % WarnOnStalledSpinLock == 0)) {
92 warning("RuntimeHistogram_lock seems to be stalled");
93 }
94 }
95 }
96
97 if (RuntimeHistogram == NULL) {
98 RuntimeHistogram = new Histogram("VM Runtime Call Counts",200);
99 }
100
101 RuntimeHistogram->add_element(this);
102 Atomic::dec(&RuntimeHistogram_lock);
103 }
104
105 void InterfaceSupport::gc_alot() {
106 Thread *thread = Thread::current();
107 if (!thread->is_Java_thread()) return; // Avoid concurrent calls
108 // Check for new, not quite initialized thread. A thread in new mode cannot initiate a GC.
109 JavaThread *current_thread = (JavaThread *)thread;
110 if (current_thread->active_handles() == NULL) return;
111
112 // Short-circuit any possible re-entrant gc-a-lot attempt
113 if (thread->skip_gcalot()) return;
114
115 if (Threads::is_vm_complete()) {
116
117 if (++_fullgc_alot_invocation < FullGCALotStart) {
118 return;
119 }
120
121 // Use this line if you want to block at a specific point,
122 // e.g. one number_of_calls/scavenge/gc before you got into problems
123 if (FullGCALot) _fullgc_alot_counter--;
124
125 // Check if we should force a full gc
126 if (_fullgc_alot_counter == 0) {
127 // Release dummy so objects are forced to move
128 if (!Universe::release_fullgc_alot_dummy()) {
129 warning("FullGCALot: Unable to release more dummies at bottom of heap");
130 }
131 HandleMark hm(thread);
132 Universe::heap()->collect(GCCause::_full_gc_alot);
133 unsigned int invocations = Universe::heap()->total_full_collections();
134 // Compute new interval
135 if (FullGCALotInterval > 1) {
136 _fullgc_alot_counter = 1+(long)((double)FullGCALotInterval*os::random()/(max_jint+1.0));
137 log_trace(gc)("Full gc no: %u\tInterval: %ld", invocations, _fullgc_alot_counter);
138 } else {
139 _fullgc_alot_counter = 1;
140 }
141 // Print progress message
142 if (invocations % 100 == 0) {
143 log_trace(gc)("Full gc no: %u", invocations);
144 }
145 } else {
146 if (ScavengeALot) _scavenge_alot_counter--;
147 // Check if we should force a scavenge
148 if (_scavenge_alot_counter == 0) {
149 HandleMark hm(thread);
150 Universe::heap()->collect(GCCause::_scavenge_alot);
151 unsigned int invocations = Universe::heap()->total_collections() - Universe::heap()->total_full_collections();
152 // Compute new interval
153 if (ScavengeALotInterval > 1) {
154 _scavenge_alot_counter = 1+(long)((double)ScavengeALotInterval*os::random()/(max_jint+1.0));
155 log_trace(gc)("Scavenge no: %u\tInterval: %ld", invocations, _scavenge_alot_counter);
156 } else {
157 _scavenge_alot_counter = 1;
158 }
159 // Print progress message
160 if (invocations % 1000 == 0) {
161 log_trace(gc)("Scavenge no: %u", invocations);
162 }
163 }
164 }
165 }
166 }
167
168
169 vframe* vframe_array[50];
170 int walk_stack_counter = 0;
171
172 void InterfaceSupport::walk_stack_from(vframe* start_vf) {
173 // walk
174 int i = 0;
175 for (vframe* f = start_vf; f; f = f->sender() ) {
176 if (i < 50) vframe_array[i++] = f;
177 }
178 }
179
180
181 void InterfaceSupport::walk_stack() {
182 JavaThread* thread = JavaThread::current();
183 walk_stack_counter++;
184 if (!thread->has_last_Java_frame()) return;
185 ResourceMark rm(thread);
186 RegisterMap reg_map(thread);
187 walk_stack_from(thread->last_java_vframe(®_map));
188 }
189
190 // invocation counter for InterfaceSupport::deoptimizeAll/zombieAll functions
191 int deoptimizeAllCounter = 0;
192 int zombieAllCounter = 0;
193
194 void InterfaceSupport::zombieAll() {
195 // This method is called by all threads when a thread make
196 // transition to VM state (for example, runtime calls).
197 // Divide number of calls by number of threads to avoid
198 // dependence of ZombieAll events frequency on number of threads.
199 int value = zombieAllCounter / Threads::number_of_threads();
200 if (is_init_completed() && value > ZombieALotInterval) {
201 zombieAllCounter = 0;
202 VM_ZombieAll op;
203 VMThread::execute(&op);
204 }
205 zombieAllCounter++;
206 }
207
208 void InterfaceSupport::unlinkSymbols() {
209 VM_UnlinkSymbols op;
210 VMThread::execute(&op);
211 }
212
213 void InterfaceSupport::deoptimizeAll() {
214 // This method is called by all threads when a thread make
215 // transition to VM state (for example, runtime calls).
216 // Divide number of calls by number of threads to avoid
217 // dependence of DeoptimizeAll events frequency on number of threads.
218 int value = deoptimizeAllCounter / Threads::number_of_threads();
219 if (is_init_completed()) {
220 if (DeoptimizeALot && value > DeoptimizeALotInterval) {
221 deoptimizeAllCounter = 0;
222 VM_DeoptimizeAll op;
223 VMThread::execute(&op);
224 } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {
225 VM_DeoptimizeAll op;
226 VMThread::execute(&op);
227 }
228 }
229 deoptimizeAllCounter++;
230 }
231
232
233 void InterfaceSupport::stress_derived_pointers() {
234 #ifdef COMPILER2
235 JavaThread *thread = JavaThread::current();
236 if (!is_init_completed()) return;
237 ResourceMark rm(thread);
238 bool found = false;
239 for (StackFrameStream sfs(thread); !sfs.is_done() && !found; sfs.next()) {
240 CodeBlob* cb = sfs.current()->cb();
241 if (cb != NULL && cb->oop_maps() ) {
242 // Find oopmap for current method
243 const ImmutableOopMap* map = cb->oop_map_for_return_address(sfs.current()->pc());
244 assert(map != NULL, "no oopmap found for pc");
245 found = map->has_derived_pointer();
246 }
247 }
248 if (found) {
249 // $$$ Not sure what to do here.
250 /*
251 Scavenge::invoke(0);
252 */
253 }
254 #endif
255 }
256
257
258 void InterfaceSupport::verify_stack() {
259 JavaThread* thread = JavaThread::current();
260 ResourceMark rm(thread);
261 // disabled because it throws warnings that oop maps should only be accessed
262 // in VM thread or during debugging
263
264 if (!thread->has_pending_exception()) {
265 // verification does not work if there are pending exceptions
266 StackFrameStream sfs(thread);
267 CodeBlob* cb = sfs.current()->cb();
268 // In case of exceptions we might not have a runtime_stub on
269 // top of stack, hence, all callee-saved registers are not going
270 // to be setup correctly, hence, we cannot do stack verify
271 if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;
272
273 for (; !sfs.is_done(); sfs.next()) {
274 sfs.current()->verify(sfs.register_map());
275 }
276 }
277 }
278
279
280 void InterfaceSupport::verify_last_frame() {
281 JavaThread* thread = JavaThread::current();
282 ResourceMark rm(thread);
283 RegisterMap reg_map(thread);
284 frame fr = thread->last_frame();
285 fr.verify(®_map);
286 }
287
288
289 #endif // ASSERT
290
291
292 void InterfaceSupport_init() {
293 #ifdef ASSERT
294 if (ScavengeALot || FullGCALot) {
295 srand(ScavengeALotInterval * FullGCALotInterval);
296 }
297 #endif
298 }