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 "gc/shared/genCollectedHeap.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.inline.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 if (UnlinkSymbolsALot) {
70 InterfaceSupport::unlinkSymbols();
71 }
72 // do verification AFTER potential deoptimization
73 if (VerifyStack) {
74 InterfaceSupport::verify_stack();
75 }
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(1, &RuntimeHistogram_lock, 0) != 0) {
91 while (OrderAccess::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::unlinkSymbols() {
212 VM_UnlinkSymbols op;
213 VMThread::execute(&op);
214 }
215
216 void InterfaceSupport::deoptimizeAll() {
217 // This method is called by all threads when a thread make
218 // transition to VM state (for example, runtime calls).
219 // Divide number of calls by number of threads to avoid
220 // dependence of DeoptimizeAll events frequency on number of threads.
221 int value = deoptimizeAllCounter / Threads::number_of_threads();
222 if (is_init_completed()) {
223 if (DeoptimizeALot && value > DeoptimizeALotInterval) {
224 deoptimizeAllCounter = 0;
225 VM_DeoptimizeAll op;
226 VMThread::execute(&op);
227 } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {
228 VM_DeoptimizeAll op;
229 VMThread::execute(&op);
230 }
231 }
232 deoptimizeAllCounter++;
233 }
234
235
236 void InterfaceSupport::stress_derived_pointers() {
237 #ifdef COMPILER2
238 JavaThread *thread = JavaThread::current();
239 if (!is_init_completed()) return;
240 ResourceMark rm(thread);
241 bool found = false;
242 for (StackFrameStream sfs(thread); !sfs.is_done() && !found; sfs.next()) {
243 CodeBlob* cb = sfs.current()->cb();
244 if (cb != NULL && cb->oop_maps() ) {
245 // Find oopmap for current method
246 const ImmutableOopMap* map = cb->oop_map_for_return_address(sfs.current()->pc());
247 assert(map != NULL, "no oopmap found for pc");
248 found = map->has_derived_pointer();
249 }
250 }
251 if (found) {
252 // $$$ Not sure what to do here.
253 /*
254 Scavenge::invoke(0);
255 */
256 }
257 #endif
258 }
259
260
261 void InterfaceSupport::verify_stack() {
262 JavaThread* thread = JavaThread::current();
263 ResourceMark rm(thread);
264 // disabled because it throws warnings that oop maps should only be accessed
265 // in VM thread or during debugging
266
267 if (!thread->has_pending_exception()) {
268 // verification does not work if there are pending exceptions
269 StackFrameStream sfs(thread);
270 CodeBlob* cb = sfs.current()->cb();
271 // In case of exceptions we might not have a runtime_stub on
272 // top of stack, hence, all callee-saved registers are not going
273 // to be setup correctly, hence, we cannot do stack verify
274 if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;
275
276 for (; !sfs.is_done(); sfs.next()) {
277 sfs.current()->verify(sfs.register_map());
278 }
279 }
280 }
281
282
283 void InterfaceSupport::verify_last_frame() {
284 JavaThread* thread = JavaThread::current();
285 ResourceMark rm(thread);
286 RegisterMap reg_map(thread);
287 frame fr = thread->last_frame();
288 fr.verify(®_map);
289 }
290
291
292 #endif // ASSERT
293
294
295 void InterfaceSupport_init() {
296 #ifdef ASSERT
297 if (ScavengeALot || FullGCALot) {
298 srand(ScavengeALotInterval * FullGCALotInterval);
299 }
300 #endif
301 }
302
303 #ifdef ASSERT
304 // JRT_LEAF rules:
305 // A JRT_LEAF method may not interfere with safepointing by
306 // 1) acquiring or blocking on a Mutex or JavaLock - checked
307 // 2) allocating heap memory - checked
308 // 3) executing a VM operation - checked
309 // 4) executing a system call (including malloc) that could block or grab a lock
310 // 5) invoking GC
311 // 6) reaching a safepoint
312 // 7) running too long
313 // Nor may any method it calls.
314 JRTLeafVerifier::JRTLeafVerifier()
315 : NoSafepointVerifier(true, JRTLeafVerifier::should_verify_GC())
316 {
317 }
318
319 JRTLeafVerifier::~JRTLeafVerifier()
320 {
321 }
322
323 bool JRTLeafVerifier::should_verify_GC() {
324 switch (JavaThread::current()->thread_state()) {
325 case _thread_in_Java:
326 // is in a leaf routine, there must be no safepoint.
327 return true;
328 case _thread_in_native:
329 // A native thread is not subject to safepoints.
330 // Even while it is in a leaf routine, GC is ok
331 return false;
332 default:
333 // Leaf routines cannot be called from other contexts.
334 ShouldNotReachHere();
335 return false;
336 }
337 }
338 #endif