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/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/vframe.hpp"
  39 #include "runtime/vmThread.hpp"
  40 #include "utilities/preserveException.hpp"
  41 
  42 // Implementation of InterfaceSupport
  43 
  44 #ifdef ASSERT
  45 VMEntryWrapper::VMEntryWrapper() {
  46   if (VerifyLastFrame) {
  47     InterfaceSupport::verify_last_frame();
  48   }
  49 }
  50 
  51 VMEntryWrapper::~VMEntryWrapper() {
  52   InterfaceSupport::check_gc_alot();
  53   if (WalkStackALot) {
  54     InterfaceSupport::walk_stack();
  55   }
  56 #ifdef COMPILER2
  57   // This option is not used by Compiler 1
  58   if (StressDerivedPointers) {
  59     InterfaceSupport::stress_derived_pointers();
  60   }
  61 #endif
  62   if (DeoptimizeALot || DeoptimizeRandom) {
  63     InterfaceSupport::deoptimizeAll();
  64   }
  65   if (ZombieALot) {
  66     InterfaceSupport::zombieAll();
  67   }
  68   if (UnlinkSymbolsALot) {
  69     InterfaceSupport::unlinkSymbols();
  70   }
  71   // do verification AFTER potential deoptimization
  72   if (VerifyStack) {
  73     InterfaceSupport::verify_stack();
  74   }
  75 }
  76 
  77 long InterfaceSupport::_number_of_calls       = 0;
  78 long InterfaceSupport::_scavenge_alot_counter = 1;
  79 long InterfaceSupport::_fullgc_alot_counter   = 1;
  80 long InterfaceSupport::_fullgc_alot_invocation = 0;
  81 
  82 Histogram* RuntimeHistogram;
  83 
  84 RuntimeHistogramElement::RuntimeHistogramElement(const char* elementName) {
  85   static volatile int RuntimeHistogram_lock = 0;
  86   _name = elementName;
  87   uintx count = 0;
  88 
  89   while (Atomic::cmpxchg(1, &RuntimeHistogram_lock, 0) != 0) {
  90     while (OrderAccess::load_acquire(&RuntimeHistogram_lock) != 0) {
  91       count +=1;
  92       if ( (WarnOnStalledSpinLock > 0)
  93         && (count % WarnOnStalledSpinLock == 0)) {
  94         warning("RuntimeHistogram_lock seems to be stalled");
  95       }
  96     }
  97   }
  98 
  99   if (RuntimeHistogram == NULL) {
 100     RuntimeHistogram = new Histogram("VM Runtime Call Counts",200);
 101   }
 102 
 103   RuntimeHistogram->add_element(this);
 104   Atomic::dec(&RuntimeHistogram_lock);
 105 }
 106 
 107 void InterfaceSupport::gc_alot() {
 108   Thread *thread = Thread::current();
 109   if (!thread->is_Java_thread()) return; // Avoid concurrent calls
 110   // Check for new, not quite initialized thread. A thread in new mode cannot initiate a GC.
 111   JavaThread *current_thread = (JavaThread *)thread;
 112   if (current_thread->active_handles() == NULL) return;
 113 
 114   // Short-circuit any possible re-entrant gc-a-lot attempt
 115   if (thread->skip_gcalot()) return;
 116 
 117   if (Threads::is_vm_complete()) {
 118 
 119     if (++_fullgc_alot_invocation < FullGCALotStart) {
 120       return;
 121     }
 122 
 123     // Use this line if you want to block at a specific point,
 124     // e.g. one number_of_calls/scavenge/gc before you got into problems
 125     if (FullGCALot) _fullgc_alot_counter--;
 126 
 127     // Check if we should force a full gc
 128     if (_fullgc_alot_counter == 0) {
 129       // Release dummy so objects are forced to move
 130       if (!Universe::release_fullgc_alot_dummy()) {
 131         warning("FullGCALot: Unable to release more dummies at bottom of heap");
 132       }
 133       HandleMark hm(thread);
 134       Universe::heap()->collect(GCCause::_full_gc_alot);
 135       unsigned int invocations = Universe::heap()->total_full_collections();
 136       // Compute new interval
 137       if (FullGCALotInterval > 1) {
 138         _fullgc_alot_counter = 1+(long)((double)FullGCALotInterval*os::random()/(max_jint+1.0));
 139         log_trace(gc)("Full gc no: %u\tInterval: %ld", invocations, _fullgc_alot_counter);
 140       } else {
 141         _fullgc_alot_counter = 1;
 142       }
 143       // Print progress message
 144       if (invocations % 100 == 0) {
 145         log_trace(gc)("Full gc no: %u", invocations);
 146       }
 147     } else {
 148       if (ScavengeALot) _scavenge_alot_counter--;
 149       // Check if we should force a scavenge
 150       if (_scavenge_alot_counter == 0) {
 151         HandleMark hm(thread);
 152         Universe::heap()->collect(GCCause::_scavenge_alot);
 153         unsigned int invocations = Universe::heap()->total_collections() - Universe::heap()->total_full_collections();
 154         // Compute new interval
 155         if (ScavengeALotInterval > 1) {
 156           _scavenge_alot_counter = 1+(long)((double)ScavengeALotInterval*os::random()/(max_jint+1.0));
 157           log_trace(gc)("Scavenge no: %u\tInterval: %ld", invocations, _scavenge_alot_counter);
 158         } else {
 159           _scavenge_alot_counter = 1;
 160         }
 161         // Print progress message
 162         if (invocations % 1000 == 0) {
 163           log_trace(gc)("Scavenge no: %u", invocations);
 164         }
 165       }
 166     }
 167   }
 168 }
 169 
 170 
 171 vframe* vframe_array[50];
 172 int walk_stack_counter = 0;
 173 
 174 void InterfaceSupport::walk_stack_from(vframe* start_vf) {
 175   // walk
 176   int i = 0;
 177   for (vframe* f = start_vf; f; f = f->sender() ) {
 178     if (i < 50) vframe_array[i++] = f;
 179   }
 180 }
 181 
 182 
 183 void InterfaceSupport::walk_stack() {
 184   JavaThread* thread = JavaThread::current();
 185   walk_stack_counter++;
 186   if (!thread->has_last_Java_frame()) return;
 187   ResourceMark rm(thread);
 188   RegisterMap reg_map(thread);
 189   walk_stack_from(thread->last_java_vframe(&reg_map));
 190 }
 191 
 192 // invocation counter for InterfaceSupport::deoptimizeAll/zombieAll functions
 193 int deoptimizeAllCounter = 0;
 194 int zombieAllCounter = 0;
 195 
 196 void InterfaceSupport::zombieAll() {
 197   // This method is called by all threads when a thread make
 198   // transition to VM state (for example, runtime calls).
 199   // Divide number of calls by number of threads to avoid
 200   // dependence of ZombieAll events frequency on number of threads.
 201   int value = zombieAllCounter / Threads::number_of_threads();
 202   if (is_init_completed() && value > ZombieALotInterval) {
 203     zombieAllCounter = 0;
 204     VM_ZombieAll op;
 205     VMThread::execute(&op);
 206   }
 207   zombieAllCounter++;
 208 }
 209 
 210 void InterfaceSupport::unlinkSymbols() {
 211   VM_UnlinkSymbols op;
 212   VMThread::execute(&op);
 213 }
 214 
 215 void InterfaceSupport::deoptimizeAll() {
 216   // This method is called by all threads when a thread make
 217   // transition to VM state (for example, runtime calls).
 218   // Divide number of calls by number of threads to avoid
 219   // dependence of DeoptimizeAll events frequency on number of threads.
 220   int value = deoptimizeAllCounter / Threads::number_of_threads();
 221   if (is_init_completed()) {
 222     if (DeoptimizeALot && value > DeoptimizeALotInterval) {
 223       deoptimizeAllCounter = 0;
 224       VM_DeoptimizeAll op;
 225       VMThread::execute(&op);
 226     } else if (DeoptimizeRandom && (value & 0x1F) == (os::random() & 0x1F)) {
 227       VM_DeoptimizeAll op;
 228       VMThread::execute(&op);
 229     }
 230   }
 231   deoptimizeAllCounter++;
 232 }
 233 
 234 
 235 void InterfaceSupport::stress_derived_pointers() {
 236 #ifdef COMPILER2
 237   JavaThread *thread = JavaThread::current();
 238   if (!is_init_completed()) return;
 239   ResourceMark rm(thread);
 240   bool found = false;
 241   for (StackFrameStream sfs(thread); !sfs.is_done() && !found; sfs.next()) {
 242     CodeBlob* cb = sfs.current()->cb();
 243     if (cb != NULL && cb->oop_maps() ) {
 244       // Find oopmap for current method
 245       const ImmutableOopMap* map = cb->oop_map_for_return_address(sfs.current()->pc());
 246       assert(map != NULL, "no oopmap found for pc");
 247       found = map->has_derived_pointer();
 248     }
 249   }
 250   if (found) {
 251     // $$$ Not sure what to do here.
 252     /*
 253     Scavenge::invoke(0);
 254     */
 255   }
 256 #endif
 257 }
 258 
 259 
 260 void InterfaceSupport::verify_stack() {
 261   JavaThread* thread = JavaThread::current();
 262   ResourceMark rm(thread);
 263   // disabled because it throws warnings that oop maps should only be accessed
 264   // in VM thread or during debugging
 265 
 266   if (!thread->has_pending_exception()) {
 267     // verification does not work if there are pending exceptions
 268     StackFrameStream sfs(thread);
 269     CodeBlob* cb = sfs.current()->cb();
 270       // In case of exceptions we might not have a runtime_stub on
 271       // top of stack, hence, all callee-saved registers are not going
 272       // to be setup correctly, hence, we cannot do stack verify
 273     if (cb != NULL && !(cb->is_runtime_stub() || cb->is_uncommon_trap_stub())) return;
 274 
 275     for (; !sfs.is_done(); sfs.next()) {
 276       sfs.current()->verify(sfs.register_map());
 277     }
 278   }
 279 }
 280 
 281 
 282 void InterfaceSupport::verify_last_frame() {
 283   JavaThread* thread = JavaThread::current();
 284   ResourceMark rm(thread);
 285   RegisterMap reg_map(thread);
 286   frame fr = thread->last_frame();
 287   fr.verify(&reg_map);
 288 }
 289 
 290 
 291 #endif // ASSERT
 292 
 293 
 294 void InterfaceSupport_init() {
 295 #ifdef ASSERT
 296   if (ScavengeALot || FullGCALot) {
 297     srand(ScavengeALotInterval * FullGCALotInterval);
 298   }
 299 #endif
 300 }