1 /*
2 * Copyright (c) 1997, 2018, 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 "runtime/atomic.hpp"
31 #include "runtime/frame.inline.hpp"
32 #include "runtime/handles.inline.hpp"
33 #include "runtime/init.hpp"
34 #include "runtime/interfaceSupport.inline.hpp"
35 #include "runtime/orderAccess.hpp"
36 #include "runtime/os.inline.hpp"
37 #include "runtime/thread.inline.hpp"
38 #include "runtime/safepointVerifiers.hpp"
39 #include "runtime/vframe.hpp"
40 #include "runtime/vmThread.hpp"
41 #include "utilities/preserveException.hpp"
42
43 // Implementation of InterfaceSupport
44
45 #ifdef ASSERT
46 VMEntryWrapper::VMEntryWrapper() {
47 if (VerifyLastFrame) {
48 InterfaceSupport::verify_last_frame();
49 }
50 }
51
52 VMEntryWrapper::~VMEntryWrapper() {
53 InterfaceSupport::check_gc_alot();
54 if (WalkStackALot) {
55 InterfaceSupport::walk_stack();
56 }
57 #ifdef COMPILER2
58 // This option is not used by Compiler 1
59 if (StressDerivedPointers) {
60 InterfaceSupport::stress_derived_pointers();
61 }
62 #endif
63 if (DeoptimizeALot || DeoptimizeRandom) {
64 InterfaceSupport::deoptimizeAll();
65 }
66 if (ZombieALot) {
67 InterfaceSupport::zombieAll();
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::deoptimizeAll() {
209 // This method is called by all threads when a thread make
210 // transition to VM state (for example, runtime calls).
211 // Divide number of calls by number of threads to avoid
212 // dependence of DeoptimizeAll events frequency on number of threads.
213 int value = deoptimizeAllCounter / Threads::number_of_threads();
214 if (is_init_completed()) {
215 if (DeoptimizeALot && value > DeoptimizeALotInterval) {
216 deoptimizeAllCounter = 0;
217 VM_DeoptimizeAll op;
218 VMThread::execute(&op);
219 } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {
220 VM_DeoptimizeAll op;
221 VMThread::execute(&op);
222 }
223 }
224 deoptimizeAllCounter++;
225 }
226
227
228 void InterfaceSupport::stress_derived_pointers() {
229 #ifdef COMPILER2
230 JavaThread *thread = JavaThread::current();
231 if (!is_init_completed()) return;
232 ResourceMark rm(thread);
233 bool found = false;
234 for (StackFrameStream sfs(thread); !sfs.is_done() && !found; sfs.next()) {
235 CodeBlob* cb = sfs.current()->cb();
236 if (cb != NULL && cb->oop_maps() ) {
237 // Find oopmap for current method
238 const ImmutableOopMap* map = cb->oop_map_for_return_address(sfs.current()->pc());
239 assert(map != NULL, "no oopmap found for pc");
240 found = map->has_derived_pointer();
241 }
242 }
243 if (found) {
244 // $$$ Not sure what to do here.
245 /*
246 Scavenge::invoke(0);
247 */
248 }
249 #endif
250 }
251
252
253 void InterfaceSupport::verify_stack() {
254 JavaThread* thread = JavaThread::current();
255 ResourceMark rm(thread);
256 // disabled because it throws warnings that oop maps should only be accessed
257 // in VM thread or during debugging
258
259 if (!thread->has_pending_exception()) {
260 // verification does not work if there are pending exceptions
261 StackFrameStream sfs(thread);
262 CodeBlob* cb = sfs.current()->cb();
263 // In case of exceptions we might not have a runtime_stub on
264 // top of stack, hence, all callee-saved registers are not going
265 // to be setup correctly, hence, we cannot do stack verify
266 if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;
267
268 for (; !sfs.is_done(); sfs.next()) {
269 sfs.current()->verify(sfs.register_map());
270 }
271 }
272 }
273
274
275 void InterfaceSupport::verify_last_frame() {
276 JavaThread* thread = JavaThread::current();
277 ResourceMark rm(thread);
278 RegisterMap reg_map(thread);
279 frame fr = thread->last_frame();
280 fr.verify(®_map);
281 }
282
283
284 #endif // ASSERT
285
286
287 void InterfaceSupport_init() {
288 #ifdef ASSERT
289 if (ScavengeALot || FullGCALot) {
290 srand(ScavengeALotInterval * FullGCALotInterval);
291 }
292 #endif
293 }
294
295 #ifdef ASSERT
296 // JRT_LEAF rules:
297 // A JRT_LEAF method may not interfere with safepointing by
298 // 1) acquiring or blocking on a Mutex or JavaLock - checked
299 // 2) allocating heap memory - checked
300 // 3) executing a VM operation - checked
301 // 4) executing a system call (including malloc) that could block or grab a lock
302 // 5) invoking GC
303 // 6) reaching a safepoint
304 // 7) running too long
305 // Nor may any method it calls.
306 JRTLeafVerifier::JRTLeafVerifier()
307 : NoSafepointVerifier(true, JRTLeafVerifier::should_verify_GC())
308 {
309 }
310
311 JRTLeafVerifier::~JRTLeafVerifier()
312 {
313 }
314
315 bool JRTLeafVerifier::should_verify_GC() {
316 switch (JavaThread::current()->thread_state()) {
317 case _thread_in_Java:
318 // is in a leaf routine, there must be no safepoint.
319 return true;
320 case _thread_in_native:
321 // A native thread is not subject to safepoints.
322 // Even while it is in a leaf routine, GC is ok
323 return false;
324 default:
325 // Leaf routines cannot be called from other contexts.
326 ShouldNotReachHere();
327 return false;
328 }
329 }
330 #endif // ASSERT