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(&reg_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(&reg_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 }
--- EOF ---