1 /* 2 * Copyright (c) 1997, 2020, 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/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 if (DeoptimizeALot || DeoptimizeRandom) { 58 InterfaceSupport::deoptimizeAll(); 59 } 60 if (ZombieALot) { 61 InterfaceSupport::zombieAll(); 62 } 63 // do verification AFTER potential deoptimization 64 if (VerifyStack) { 65 InterfaceSupport::verify_stack(); 66 } 67 } 68 69 VMNativeEntryWrapper::VMNativeEntryWrapper() { 70 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot(); 71 } 72 73 VMNativeEntryWrapper::~VMNativeEntryWrapper() { 74 if (GCALotAtAllSafepoints) InterfaceSupport::check_gc_alot(); 75 } 76 77 long InterfaceSupport::_scavenge_alot_counter = 1; 78 long InterfaceSupport::_fullgc_alot_counter = 1; 79 long InterfaceSupport::_fullgc_alot_invocation = 0; 80 81 Histogram* RuntimeHistogram; 82 83 RuntimeHistogramElement::RuntimeHistogramElement(const char* elementName) { 84 static volatile int RuntimeHistogram_lock = 0; 85 _name = elementName; 86 uintx count = 0; 87 88 while (Atomic::cmpxchg(&RuntimeHistogram_lock, 0, 1) != 0) { 89 while (Atomic::load_acquire(&RuntimeHistogram_lock) != 0) { 90 count +=1; 91 if ( (WarnOnStalledSpinLock > 0) 92 && (count % WarnOnStalledSpinLock == 0)) { 93 warning("RuntimeHistogram_lock seems to be stalled"); 94 } 95 } 96 } 97 98 if (RuntimeHistogram == NULL) { 99 RuntimeHistogram = new Histogram("VM Runtime Call Counts",200); 100 } 101 102 RuntimeHistogram->add_element(this); 103 Atomic::dec(&RuntimeHistogram_lock); 104 } 105 106 void InterfaceSupport::gc_alot() { 107 Thread *thread = Thread::current(); 108 if (!thread->is_Java_thread()) return; // Avoid concurrent calls 109 // Check for new, not quite initialized thread. A thread in new mode cannot initiate a GC. 110 JavaThread *current_thread = (JavaThread *)thread; 111 if (current_thread->active_handles() == NULL) return; 112 113 // Short-circuit any possible re-entrant gc-a-lot attempt 114 if (thread->skip_gcalot()) return; 115 116 if (Threads::is_vm_complete()) { 117 118 if (++_fullgc_alot_invocation < FullGCALotStart) { 119 return; 120 } 121 122 // Use this line if you want to block at a specific point, 123 // e.g. one number_of_calls/scavenge/gc before you got into problems 124 if (FullGCALot) _fullgc_alot_counter--; 125 126 // Check if we should force a full gc 127 if (_fullgc_alot_counter == 0) { 128 // Release dummy so objects are forced to move 129 if (!Universe::release_fullgc_alot_dummy()) { 130 warning("FullGCALot: Unable to release more dummies at bottom of heap"); 131 } 132 HandleMark hm(thread); 133 Universe::heap()->collect(GCCause::_full_gc_alot); 134 unsigned int invocations = Universe::heap()->total_full_collections(); 135 // Compute new interval 136 if (FullGCALotInterval > 1) { 137 _fullgc_alot_counter = 1+(long)((double)FullGCALotInterval*os::random()/(max_jint+1.0)); 138 log_trace(gc)("Full gc no: %u\tInterval: %ld", invocations, _fullgc_alot_counter); 139 } else { 140 _fullgc_alot_counter = 1; 141 } 142 // Print progress message 143 if (invocations % 100 == 0) { 144 log_trace(gc)("Full gc no: %u", invocations); 145 } 146 } else { 147 if (ScavengeALot) _scavenge_alot_counter--; 148 // Check if we should force a scavenge 149 if (_scavenge_alot_counter == 0) { 150 HandleMark hm(thread); 151 Universe::heap()->collect(GCCause::_scavenge_alot); 152 unsigned int invocations = Universe::heap()->total_collections() - Universe::heap()->total_full_collections(); 153 // Compute new interval 154 if (ScavengeALotInterval > 1) { 155 _scavenge_alot_counter = 1+(long)((double)ScavengeALotInterval*os::random()/(max_jint+1.0)); 156 log_trace(gc)("Scavenge no: %u\tInterval: %ld", invocations, _scavenge_alot_counter); 157 } else { 158 _scavenge_alot_counter = 1; 159 } 160 // Print progress message 161 if (invocations % 1000 == 0) { 162 log_trace(gc)("Scavenge no: %u", invocations); 163 } 164 } 165 } 166 } 167 } 168 169 170 vframe* vframe_array[50]; 171 int walk_stack_counter = 0; 172 173 void InterfaceSupport::walk_stack_from(vframe* start_vf) { 174 // walk 175 int i = 0; 176 for (vframe* f = start_vf; f; f = f->sender() ) { 177 if (i < 50) vframe_array[i++] = f; 178 } 179 } 180 181 182 void InterfaceSupport::walk_stack() { 183 JavaThread* thread = JavaThread::current(); 184 walk_stack_counter++; 185 if (!thread->has_last_Java_frame()) return; 186 ResourceMark rm(thread); 187 RegisterMap reg_map(thread); 188 walk_stack_from(thread->last_java_vframe(®_map)); 189 } 190 191 // invocation counter for InterfaceSupport::deoptimizeAll/zombieAll functions 192 int deoptimizeAllCounter = 0; 193 int zombieAllCounter = 0; 194 195 void InterfaceSupport::zombieAll() { 196 // This method is called by all threads when a thread make 197 // transition to VM state (for example, runtime calls). 198 // Divide number of calls by number of threads to avoid 199 // dependence of ZombieAll events frequency on number of threads. 200 int value = zombieAllCounter / Threads::number_of_threads(); 201 if (is_init_completed() && value > ZombieALotInterval) { 202 zombieAllCounter = 0; 203 VM_ZombieAll op; 204 VMThread::execute(&op); 205 } 206 zombieAllCounter++; 207 } 208 209 void InterfaceSupport::deoptimizeAll() { 210 // This method is called by all threads when a thread make 211 // transition to VM state (for example, runtime calls). 212 // Divide number of calls by number of threads to avoid 213 // dependence of DeoptimizeAll events frequency on number of threads. 214 int value = deoptimizeAllCounter / Threads::number_of_threads(); 215 if (is_init_completed()) { 216 if (DeoptimizeALot && value > DeoptimizeALotInterval) { 217 deoptimizeAllCounter = 0; 218 VM_DeoptimizeAll op; 219 VMThread::execute(&op); 220 } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) { 221 VM_DeoptimizeAll op; 222 VMThread::execute(&op); 223 } 224 } 225 deoptimizeAllCounter++; 226 } 227 228 229 void InterfaceSupport::verify_stack() { 230 JavaThread* thread = JavaThread::current(); 231 ResourceMark rm(thread); 232 // disabled because it throws warnings that oop maps should only be accessed 233 // in VM thread or during debugging 234 235 if (!thread->has_pending_exception()) { 236 // verification does not work if there are pending exceptions 237 StackFrameStream sfs(thread); 238 CodeBlob* cb = sfs.current()->cb(); 239 // In case of exceptions we might not have a runtime_stub on 240 // top of stack, hence, all callee-saved registers are not going 241 // to be setup correctly, hence, we cannot do stack verify 242 if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return; 243 244 for (; !sfs.is_done(); sfs.next()) { 245 sfs.current()->verify(sfs.register_map()); 246 } 247 } 248 } 249 250 251 void InterfaceSupport::verify_last_frame() { 252 JavaThread* thread = JavaThread::current(); 253 ResourceMark rm(thread); 254 RegisterMap reg_map(thread); 255 frame fr = thread->last_frame(); 256 fr.verify(®_map); 257 } 258 259 260 #endif // ASSERT 261 262 263 void InterfaceSupport_init() { 264 #ifdef ASSERT 265 if (ScavengeALot || FullGCALot) { 266 srand(ScavengeALotInterval * FullGCALotInterval); 267 } 268 #endif 269 }