1 /*
   2  * Copyright (c) 1997, 2013, 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 "code/codeCache.hpp"
  27 #include "code/compiledIC.hpp"
  28 #include "code/icBuffer.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "compiler/compileBroker.hpp"
  31 #include "memory/resourceArea.hpp"
  32 #include "oops/method.hpp"
  33 #include "runtime/atomic.hpp"
  34 #include "runtime/compilationPolicy.hpp"
  35 #include "runtime/mutexLocker.hpp"
  36 #include "runtime/os.hpp"
  37 #include "runtime/sweeper.hpp"
  38 #include "runtime/vm_operations.hpp"
  39 #include "trace/tracing.hpp"
  40 #include "utilities/events.hpp"
  41 #include "utilities/xmlstream.hpp"
  42 
  43 #ifdef ASSERT
  44 
  45 #define SWEEP(nm) record_sweep(nm, __LINE__)
  46 // Sweeper logging code
  47 class SweeperRecord {
  48  public:
  49   int traversal;
  50   int invocation;
  51   int compile_id;
  52   long traversal_mark;
  53   int state;
  54   const char* kind;
  55   address vep;
  56   address uep;
  57   int line;
  58 
  59   void print() {
  60       tty->print_cr("traversal = %d invocation = %d compile_id = %d %s uep = " PTR_FORMAT " vep = "
  61                     PTR_FORMAT " state = %d traversal_mark %d line = %d",
  62                     traversal,
  63                     invocation,
  64                     compile_id,
  65                     kind == NULL ? "" : kind,
  66                     uep,
  67                     vep,
  68                     state,
  69                     traversal_mark,
  70                     line);
  71   }
  72 };
  73 
  74 static int _sweep_index = 0;
  75 static SweeperRecord* _records = NULL;
  76 
  77 void NMethodSweeper::report_events(int id, address entry) {
  78   if (_records != NULL) {
  79     for (int i = _sweep_index; i < SweeperLogEntries; i++) {
  80       if (_records[i].uep == entry ||
  81           _records[i].vep == entry ||
  82           _records[i].compile_id == id) {
  83         _records[i].print();
  84       }
  85     }
  86     for (int i = 0; i < _sweep_index; i++) {
  87       if (_records[i].uep == entry ||
  88           _records[i].vep == entry ||
  89           _records[i].compile_id == id) {
  90         _records[i].print();
  91       }
  92     }
  93   }
  94 }
  95 
  96 void NMethodSweeper::report_events() {
  97   if (_records != NULL) {
  98     for (int i = _sweep_index; i < SweeperLogEntries; i++) {
  99       // skip empty records
 100       if (_records[i].vep == NULL) continue;
 101       _records[i].print();
 102     }
 103     for (int i = 0; i < _sweep_index; i++) {
 104       // skip empty records
 105       if (_records[i].vep == NULL) continue;
 106       _records[i].print();
 107     }
 108   }
 109 }
 110 
 111 void NMethodSweeper::record_sweep(nmethod* nm, int line) {
 112   if (_records != NULL) {
 113     _records[_sweep_index].traversal = _traversals;
 114     _records[_sweep_index].traversal_mark = nm->_stack_traversal_mark;
 115     _records[_sweep_index].invocation = _invocations;
 116     _records[_sweep_index].compile_id = nm->compile_id();
 117     _records[_sweep_index].kind = nm->compile_kind();
 118     _records[_sweep_index].state = nm->_state;
 119     _records[_sweep_index].vep = nm->verified_entry_point();
 120     _records[_sweep_index].uep = nm->entry_point();
 121     _records[_sweep_index].line = line;
 122 
 123     _sweep_index = (_sweep_index + 1) % SweeperLogEntries;
 124   }
 125 }
 126 #else
 127 #define SWEEP(nm)
 128 #endif
 129 
 130 
 131 long      NMethodSweeper::_traversals = 0;   // No. of stack traversals performed
 132 nmethod*  NMethodSweeper::_current = NULL;   // Current nmethod
 133 int       NMethodSweeper::_seen = 0 ;        // No. of nmethods we have currently processed in current pass of CodeCache
 134 int       NMethodSweeper::_flushed_count = 0;   // Nof. nmethods flushed in current sweep
 135 int       NMethodSweeper::_zombified_count = 0; // Nof. nmethods made zombie in current sweep
 136 int       NMethodSweeper::_marked_count = 0;    // Nof. nmethods marked for reclaim in current sweep
 137 
 138 volatile int NMethodSweeper::_invocations = 0;   // No. of invocations left until we are completed with this pass
 139 volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress.
 140 
 141 jint      NMethodSweeper::_locked_seen = 0;
 142 jint      NMethodSweeper::_not_entrant_seen_on_stack = 0;
 143 bool      NMethodSweeper::_resweep = false;
 144 jint      NMethodSweeper::_flush_token = 0;
 145 jlong     NMethodSweeper::_last_full_flush_time = 0;
 146 int       NMethodSweeper::_highest_marked = 0;
 147 int       NMethodSweeper::_dead_compile_ids = 0;
 148 long      NMethodSweeper::_last_flush_traversal_id = 0;
 149 
 150 int       NMethodSweeper::_number_of_flushes = 0; // Total of full traversals caused by full cache
 151 int       NMethodSweeper::_total_nof_methods_reclaimed = 0;
 152 jlong     NMethodSweeper::_total_time_sweeping = 0;
 153 jlong     NMethodSweeper::_total_time_this_sweep = 0;
 154 jlong     NMethodSweeper::_peak_sweep_time = 0;
 155 jlong     NMethodSweeper::_peak_sweep_fraction_time = 0;
 156 jlong     NMethodSweeper::_total_disconnect_time = 0;
 157 jlong     NMethodSweeper::_peak_disconnect_time = 0;
 158 
 159 class MarkActivationClosure: public CodeBlobClosure {
 160 public:
 161   virtual void do_code_blob(CodeBlob* cb) {
 162     // If we see an activation belonging to a non_entrant nmethod, we mark it.
 163     if (cb->is_nmethod() && ((nmethod*)cb)->is_not_entrant()) {
 164       ((nmethod*)cb)->mark_as_seen_on_stack();
 165     }
 166   }
 167 };
 168 static MarkActivationClosure mark_activation_closure;
 169 
 170 bool NMethodSweeper::sweep_in_progress() {
 171   return (_current != NULL);
 172 }
 173 
 174 void NMethodSweeper::scan_stacks() {
 175   assert(SafepointSynchronize::is_at_safepoint(), "must be executed at a safepoint");
 176   if (!MethodFlushing) return;
 177 
 178   // No need to synchronize access, since this is always executed at a
 179   // safepoint.
 180 
 181   // Make sure CompiledIC_lock in unlocked, since we might update some
 182   // inline caches. If it is, we just bail-out and try later.
 183   if (CompiledIC_lock->is_locked() || Patching_lock->is_locked()) return;
 184 
 185   // Check for restart
 186   assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid");
 187   if (!sweep_in_progress() && _resweep) {
 188     _seen        = 0;
 189     _invocations = NmethodSweepFraction;
 190     _current     = CodeCache::first_nmethod();
 191     _traversals  += 1;
 192     _total_time_this_sweep = 0;
 193 
 194     if (PrintMethodFlushing) {
 195       tty->print_cr("### Sweep: stack traversal %d", _traversals);
 196     }
 197     Threads::nmethods_do(&mark_activation_closure);
 198 
 199     // reset the flags since we started a scan from the beginning.
 200     _resweep = false;
 201     _locked_seen = 0;
 202     _not_entrant_seen_on_stack = 0;
 203   }
 204 
 205   if (UseCodeCacheFlushing) {
 206     // only allow new flushes after the interval is complete.
 207     jlong now           = os::javaTimeMillis();
 208     jlong max_interval  = (jlong)MinCodeCacheFlushingInterval * (jlong)1000;
 209     jlong curr_interval = now - _last_full_flush_time;
 210     if (curr_interval > max_interval) {
 211       _flush_token = 0;
 212     }
 213 
 214     if (!CodeCache::needs_flushing() && !CompileBroker::should_compile_new_jobs()) {
 215       CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
 216       log_sweep("restart_compiler");
 217     }
 218   }
 219 }
 220 
 221 void NMethodSweeper::possibly_sweep() {
 222   assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode");
 223   if (!MethodFlushing || !sweep_in_progress()) return;
 224 
 225   if (_invocations > 0) {
 226     // Only one thread at a time will sweep
 227     jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 );
 228     if (old != 0) {
 229       return;
 230     }
 231 #ifdef ASSERT
 232     if (LogSweeper && _records == NULL) {
 233       // Create the ring buffer for the logging code
 234       _records = NEW_C_HEAP_ARRAY(SweeperRecord, SweeperLogEntries, mtGC);
 235       memset(_records, 0, sizeof(SweeperRecord) * SweeperLogEntries);
 236     }
 237 #endif
 238     if (_invocations > 0) {
 239       sweep_code_cache();
 240       _invocations--;
 241     }
 242     _sweep_started = 0;
 243   }
 244 }
 245 
 246 void NMethodSweeper::sweep_code_cache() {
 247 
 248   jlong sweep_start_counter = os::elapsed_counter();
 249 
 250   _flushed_count   = 0;
 251   _zombified_count = 0;
 252   _marked_count    = 0;
 253 
 254   if (PrintMethodFlushing && Verbose) {
 255     tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations);
 256   }
 257 
 258   if (!CompileBroker::should_compile_new_jobs()) {
 259     // If we have turned off compilations we might as well do full sweeps
 260     // in order to reach the clean state faster. Otherwise the sleeping compiler
 261     // threads will slow down sweeping. After a few iterations the cache
 262     // will be clean and sweeping stops (_resweep will not be set)
 263     _invocations = 1;
 264   }
 265 
 266   // We want to visit all nmethods after NmethodSweepFraction
 267   // invocations so divide the remaining number of nmethods by the
 268   // remaining number of invocations.  This is only an estimate since
 269   // the number of nmethods changes during the sweep so the final
 270   // stage must iterate until it there are no more nmethods.
 271   int todo = (CodeCache::nof_nmethods() - _seen) / _invocations;
 272   int swept_count = 0;
 273 
 274   assert(!SafepointSynchronize::is_at_safepoint(), "should not be in safepoint when we get here");
 275   assert(!CodeCache_lock->owned_by_self(), "just checking");
 276 
 277   {
 278     MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 279 
 280     // The last invocation iterates until there are no more nmethods
 281     for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) {
 282       swept_count++;
 283       if (SafepointSynchronize::is_synchronizing()) { // Safepoint request
 284         if (PrintMethodFlushing && Verbose) {
 285           tty->print_cr("### Sweep at %d out of %d, invocation: %d, yielding to safepoint", _seen, CodeCache::nof_nmethods(), _invocations);
 286         }
 287         MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 288 
 289         assert(Thread::current()->is_Java_thread(), "should be java thread");
 290         JavaThread* thread = (JavaThread*)Thread::current();
 291         ThreadBlockInVM tbivm(thread);
 292         thread->java_suspend_self();
 293       }
 294       // Since we will give up the CodeCache_lock, always skip ahead
 295       // to the next nmethod.  Other blobs can be deleted by other
 296       // threads but nmethods are only reclaimed by the sweeper.
 297       nmethod* next = CodeCache::next_nmethod(_current);
 298 
 299       // Now ready to process nmethod and give up CodeCache_lock
 300       {
 301         MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 302         process_nmethod(_current);
 303       }
 304       _seen++;
 305       _current = next;
 306     }
 307   }
 308 
 309   assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache");
 310 
 311   if (!sweep_in_progress() && !_resweep && (_locked_seen || _not_entrant_seen_on_stack)) {
 312     // we've completed a scan without making progress but there were
 313     // nmethods we were unable to process either because they were
 314     // locked or were still on stack.  We don't have to aggresively
 315     // clean them up so just stop scanning.  We could scan once more
 316     // but that complicates the control logic and it's unlikely to
 317     // matter much.
 318     if (PrintMethodFlushing) {
 319       tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep");
 320     }
 321   }
 322 
 323   jlong sweep_end_counter = os::elapsed_counter();
 324   jlong sweep_time = sweep_end_counter - sweep_start_counter;
 325   _total_time_sweeping  += sweep_time;
 326   _total_time_this_sweep += sweep_time;
 327   _peak_sweep_fraction_time = MAX2(sweep_time, _peak_sweep_fraction_time);
 328   _total_nof_methods_reclaimed += _flushed_count;
 329 
 330   EventSweepCodeCache event(UNTIMED);
 331   if (event.should_commit()) {
 332     event.set_starttime(sweep_start_counter);
 333     event.set_endtime(sweep_end_counter);
 334     event.set_sweepIndex(_traversals);
 335     event.set_sweepFractionIndex(NmethodSweepFraction - _invocations + 1);
 336     event.set_sweptCount(swept_count);
 337     event.set_flushedCount(_flushed_count);
 338     event.set_markedCount(_marked_count);
 339     event.set_zombifiedCount(_zombified_count);
 340     event.commit();
 341   }
 342 
 343 #ifdef ASSERT
 344   if(PrintMethodFlushing) {
 345     tty->print_cr("### sweeper:      sweep time(%d): " INT64_FORMAT, _invocations, (jlong)sweep_time);
 346   }
 347 #endif
 348 
 349   if (_invocations == 1) {
 350     _peak_sweep_time = MAX2(_peak_sweep_time, _total_time_this_sweep);
 351     log_sweep("finished");
 352   }
 353 
 354   // Sweeper is the only case where memory is released,
 355   // check here if it is time to restart the compiler.
 356   if (UseCodeCacheFlushing && !CompileBroker::should_compile_new_jobs() && !CodeCache::needs_flushing()) {
 357     CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
 358     log_sweep("restart_compiler");
 359   }
 360 }
 361 
 362 class NMethodMarker: public StackObj {
 363  private:
 364   CompilerThread* _thread;
 365  public:
 366   NMethodMarker(nmethod* nm) {
 367     _thread = CompilerThread::current();
 368     if (!nm->is_zombie() && !nm->is_unloaded()) {
 369       // Only expose live nmethods for scanning
 370     _thread->set_scanned_nmethod(nm);
 371   }
 372   }
 373   ~NMethodMarker() {
 374     _thread->set_scanned_nmethod(NULL);
 375   }
 376 };
 377 
 378 void NMethodSweeper::release_nmethod(nmethod *nm) {
 379   // Clean up any CompiledICHolders
 380   {
 381     ResourceMark rm;
 382     MutexLocker ml_patch(CompiledIC_lock);
 383     RelocIterator iter(nm);
 384     while (iter.next()) {
 385       if (iter.type() == relocInfo::virtual_call_type) {
 386         CompiledIC::cleanup_call_site(iter.virtual_call_reloc());
 387       }
 388     }
 389   }
 390 
 391   MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
 392   nm->flush();
 393 }
 394 
 395 void NMethodSweeper::process_nmethod(nmethod *nm) {
 396   assert(!CodeCache_lock->owned_by_self(), "just checking");
 397 
 398   // Make sure this nmethod doesn't get unloaded during the scan,
 399   // since the locks acquired below might safepoint.
 400   NMethodMarker nmm(nm);
 401 
 402   SWEEP(nm);
 403 
 404   // Skip methods that are currently referenced by the VM
 405   if (nm->is_locked_by_vm()) {
 406     // But still remember to clean-up inline caches for alive nmethods
 407     if (nm->is_alive()) {
 408       // Clean-up all inline caches that points to zombie/non-reentrant methods
 409       MutexLocker cl(CompiledIC_lock);
 410       nm->cleanup_inline_caches();
 411       SWEEP(nm);
 412     } else {
 413       _locked_seen++;
 414       SWEEP(nm);
 415     }
 416     return;
 417   }
 418 
 419   if (nm->is_zombie()) {
 420     // If it is first time, we see nmethod then we mark it. Otherwise,
 421     // we reclame it. When we have seen a zombie method twice, we know that
 422     // there are no inline caches that refer to it.
 423     if (nm->is_marked_for_reclamation()) {
 424       assert(!nm->is_locked_by_vm(), "must not flush locked nmethods");
 425       if (PrintMethodFlushing && Verbose) {
 426         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm);
 427       }
 428       release_nmethod(nm);
 429       _flushed_count++;
 430     } else {
 431       if (PrintMethodFlushing && Verbose) {
 432         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm);
 433       }
 434       nm->mark_for_reclamation();
 435       _resweep = true;
 436       _marked_count++;
 437       SWEEP(nm);
 438     }
 439   } else if (nm->is_not_entrant()) {
 440     // If there is no current activations of this method on the
 441     // stack we can safely convert it to a zombie method
 442     if (nm->can_not_entrant_be_converted()) {
 443       if (PrintMethodFlushing && Verbose) {
 444         tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm);
 445       }
 446       nm->make_zombie();
 447       _resweep = true;
 448       _zombified_count++;
 449       SWEEP(nm);
 450     } else {
 451       // Still alive, clean up its inline caches
 452       MutexLocker cl(CompiledIC_lock);
 453       nm->cleanup_inline_caches();
 454       // we coudn't transition this nmethod so don't immediately
 455       // request a rescan.  If this method stays on the stack for a
 456       // long time we don't want to keep rescanning the code cache.
 457       _not_entrant_seen_on_stack++;
 458       SWEEP(nm);
 459     }
 460   } else if (nm->is_unloaded()) {
 461     // Unloaded code, just make it a zombie
 462     if (PrintMethodFlushing && Verbose)
 463       tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm);
 464 
 465     if (nm->is_osr_method()) {
 466       SWEEP(nm);
 467       // No inline caches will ever point to osr methods, so we can just remove it
 468       release_nmethod(nm);
 469       _flushed_count++;
 470     } else {
 471       nm->make_zombie();
 472       _resweep = true;
 473       _zombified_count++;
 474       SWEEP(nm);
 475     }
 476   } else {
 477     assert(nm->is_alive(), "should be alive");
 478 
 479     if (UseCodeCacheFlushing) {
 480       if (nm->is_speculatively_disconnected() && !nm->is_locked_by_vm() && !nm->is_osr_method() &&
 481           (_traversals > _last_flush_traversal_id + 2) && (nm->compile_id() < _highest_marked)) {
 482         // This method has not been called since the forced cleanup happened
 483         nm->make_not_entrant();
 484       }
 485     }
 486 
 487     // Clean-up all inline caches that points to zombie/non-reentrant methods
 488     MutexLocker cl(CompiledIC_lock);
 489     nm->cleanup_inline_caches();
 490     SWEEP(nm);
 491   }
 492 }
 493 
 494 // Code cache unloading: when compilers notice the code cache is getting full,
 495 // they will call a vm op that comes here. This code attempts to speculatively
 496 // unload the oldest half of the nmethods (based on the compile job id) by
 497 // saving the old code in a list in the CodeCache. Then
 498 // execution resumes. If a method so marked is not called by the second sweeper
 499 // stack traversal after the current one, the nmethod will be marked non-entrant and
 500 // got rid of by normal sweeping. If the method is called, the Method*'s
 501 // _code field is restored and the Method*/nmethod
 502 // go back to their normal state.
 503 void NMethodSweeper::handle_full_code_cache(bool is_full) {
 504 
 505   if (is_full) {
 506     // Since code cache is full, immediately stop new compiles
 507     if (CompileBroker::set_should_compile_new_jobs(CompileBroker::stop_compilation)) {
 508       log_sweep("disable_compiler");
 509     }
 510   }
 511 
 512   // Make sure only one thread can flush
 513   // The token is reset after CodeCacheMinimumFlushInterval in scan stacks,
 514   // no need to check the timeout here.
 515   jint old = Atomic::cmpxchg( 1, &_flush_token, 0 );
 516   if (old != 0) {
 517     return;
 518   }
 519 
 520   VM_HandleFullCodeCache op(is_full);
 521   VMThread::execute(&op);
 522 
 523   // resweep again as soon as possible
 524   _resweep = true;
 525 }
 526 
 527 void NMethodSweeper::speculative_disconnect_nmethods(bool is_full) {
 528   // If there was a race in detecting full code cache, only run
 529   // one vm op for it or keep the compiler shut off
 530 
 531   jlong disconnect_start_counter = os::elapsed_counter();
 532 
 533   // Traverse the code cache trying to dump the oldest nmethods
 534   int curr_max_comp_id = CompileBroker::get_compilation_id();
 535   int flush_target = ((curr_max_comp_id - _dead_compile_ids) / CodeCacheFlushingFraction) + _dead_compile_ids;
 536 
 537   log_sweep("start_cleaning");
 538 
 539   nmethod* nm = CodeCache::alive_nmethod(CodeCache::first());
 540   jint disconnected = 0;
 541   jint made_not_entrant  = 0;
 542   jint nmethod_count = 0;
 543 
 544   while ((nm != NULL)){
 545     int curr_comp_id = nm->compile_id();
 546 
 547     // OSR methods cannot be flushed like this. Also, don't flush native methods
 548     // since they are part of the JDK in most cases
 549     if (!nm->is_osr_method() && !nm->is_locked_by_vm() && !nm->is_native_method()) {
 550 
 551       // only count methods that can be speculatively disconnected
 552       nmethod_count++;
 553 
 554       if (nm->is_in_use() && (curr_comp_id < flush_target)) {
 555         if ((nm->method()->code() == nm)) {
 556           // This method has not been previously considered for
 557           // unloading or it was restored already
 558           CodeCache::speculatively_disconnect(nm);
 559           disconnected++;
 560         } else if (nm->is_speculatively_disconnected()) {
 561           // This method was previously considered for preemptive unloading and was not called since then
 562           CompilationPolicy::policy()->delay_compilation(nm->method());
 563           nm->make_not_entrant();
 564           made_not_entrant++;
 565         }
 566 
 567         if (curr_comp_id > _highest_marked) {
 568           _highest_marked = curr_comp_id;
 569         }
 570       }
 571     }
 572     nm = CodeCache::alive_nmethod(CodeCache::next(nm));
 573   }
 574 
 575   // remember how many compile_ids wheren't seen last flush.
 576   _dead_compile_ids = curr_max_comp_id - nmethod_count;
 577 
 578   log_sweep("stop_cleaning",
 579                        "disconnected='" UINT32_FORMAT "' made_not_entrant='" UINT32_FORMAT "'",
 580                        disconnected, made_not_entrant);
 581 
 582   // Shut off compiler. Sweeper will start over with a new stack scan and
 583   // traversal cycle and turn it back on if it clears enough space.
 584   if (is_full) {
 585     _last_full_flush_time = os::javaTimeMillis();
 586   }
 587 
 588   jlong disconnect_end_counter = os::elapsed_counter();
 589   jlong disconnect_time = disconnect_end_counter - disconnect_start_counter;
 590   _total_disconnect_time += disconnect_time;
 591   _peak_disconnect_time = MAX2(disconnect_time, _peak_disconnect_time);
 592 
 593   EventCleanCodeCache event(UNTIMED);
 594   if (event.should_commit()) {
 595     event.set_starttime(disconnect_start_counter);
 596     event.set_endtime(disconnect_end_counter);
 597     event.set_disconnectedCount(disconnected);
 598     event.set_madeNonEntrantCount(made_not_entrant);
 599     event.commit();
 600   }
 601   _number_of_flushes++;
 602 
 603   // After two more traversals the sweeper will get rid of unrestored nmethods
 604   _last_flush_traversal_id = _traversals;
 605   _resweep = true;
 606 #ifdef ASSERT
 607 
 608   if(PrintMethodFlushing && Verbose) {
 609     tty->print_cr("### sweeper: unload time: " INT64_FORMAT, (jlong)disconnect_time);
 610   }
 611 #endif
 612 }
 613 
 614 
 615 // Print out some state information about the current sweep and the
 616 // state of the code cache if it's requested.
 617 void NMethodSweeper::log_sweep(const char* msg, const char* format, ...) {
 618   if (PrintMethodFlushing) {
 619     stringStream s;
 620     // Dump code cache state into a buffer before locking the tty,
 621     // because log_state() will use locks causing lock conflicts.
 622     CodeCache::log_state(&s);
 623 
 624     ttyLocker ttyl;
 625     tty->print("### sweeper: %s ", msg);
 626     if (format != NULL) {
 627       va_list ap;
 628       va_start(ap, format);
 629       tty->vprint(format, ap);
 630       va_end(ap);
 631     }
 632     tty->print_cr(s.as_string());
 633   }
 634 
 635   if (LogCompilation && (xtty != NULL)) {
 636     stringStream s;
 637     // Dump code cache state into a buffer before locking the tty,
 638     // because log_state() will use locks causing lock conflicts.
 639     CodeCache::log_state(&s);
 640 
 641     ttyLocker ttyl;
 642     xtty->begin_elem("sweeper state='%s' traversals='" INTX_FORMAT "' ", msg, (intx)traversal_count());
 643     if (format != NULL) {
 644       va_list ap;
 645       va_start(ap, format);
 646       xtty->vprint(format, ap);
 647       va_end(ap);
 648     }
 649     xtty->print(s.as_string());
 650     xtty->stamp();
 651     xtty->end_elem();
 652   }
 653 }