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/nmethod.hpp" 28 #include "compiler/compileBroker.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/methodOop.hpp" 31 #include "runtime/atomic.hpp" 32 #include "runtime/compilationPolicy.hpp" 33 #include "runtime/mutexLocker.hpp" 34 #include "runtime/os.hpp" 35 #include "runtime/sweeper.hpp" 36 #include "runtime/vm_operations.hpp" 37 #include "utilities/events.hpp" 38 #include "utilities/xmlstream.hpp" 39 40 long NMethodSweeper::_traversals = 0; // No. of stack traversals performed 41 nmethod* NMethodSweeper::_current = NULL; // Current nmethod 42 int NMethodSweeper::_seen = 0 ; // No. of nmethods we have currently processed in current pass of CodeCache 43 44 volatile int NMethodSweeper::_invocations = 0; // No. of invocations left until we are completed with this pass 45 volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress. 46 47 jint NMethodSweeper::_locked_seen = 0; 48 jint NMethodSweeper::_not_entrant_seen_on_stack = 0; 49 bool NMethodSweeper::_rescan = false; 50 bool NMethodSweeper::_do_sweep = false; 51 bool NMethodSweeper::_was_full = false; 52 jint NMethodSweeper::_advise_to_sweep = 0; 53 jlong NMethodSweeper::_last_was_full = 0; 54 uint NMethodSweeper::_highest_marked = 0; 55 long NMethodSweeper::_was_full_traversal = 0; 56 57 class MarkActivationClosure: public CodeBlobClosure { 58 public: 59 virtual void do_code_blob(CodeBlob* cb) { 120 // Update the _last_was_full time so we can tell how fast the 121 // code cache is filling up 122 _last_was_full = os::javaTimeMillis(); 123 124 log_sweep("restart_compiler"); 125 } 126 } 127 } 128 } 129 130 void NMethodSweeper::possibly_sweep() { 131 assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode"); 132 if ((!MethodFlushing) || (!_do_sweep)) return; 133 134 if (_invocations > 0) { 135 // Only one thread at a time will sweep 136 jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 ); 137 if (old != 0) { 138 return; 139 } 140 if (_invocations > 0) { 141 sweep_code_cache(); 142 _invocations--; 143 } 144 _sweep_started = 0; 145 } 146 } 147 148 void NMethodSweeper::sweep_code_cache() { 149 #ifdef ASSERT 150 jlong sweep_start; 151 if (PrintMethodFlushing) { 152 sweep_start = os::javaTimeMillis(); 153 } 154 #endif 155 if (PrintMethodFlushing && Verbose) { 156 tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations); 157 } 158 159 // We want to visit all nmethods after NmethodSweepFraction 196 // clean them up so just stop scanning. We could scan once more 197 // but that complicates the control logic and it's unlikely to 198 // matter much. 199 if (PrintMethodFlushing) { 200 tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep"); 201 } 202 } 203 204 #ifdef ASSERT 205 if(PrintMethodFlushing) { 206 jlong sweep_end = os::javaTimeMillis(); 207 tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, sweep_end - sweep_start); 208 } 209 #endif 210 211 if (_invocations == 1) { 212 log_sweep("finished"); 213 } 214 } 215 216 217 void NMethodSweeper::process_nmethod(nmethod *nm) { 218 assert(!CodeCache_lock->owned_by_self(), "just checking"); 219 220 // Skip methods that are currently referenced by the VM 221 if (nm->is_locked_by_vm()) { 222 // But still remember to clean-up inline caches for alive nmethods 223 if (nm->is_alive()) { 224 // Clean-up all inline caches that points to zombie/non-reentrant methods 225 MutexLocker cl(CompiledIC_lock); 226 nm->cleanup_inline_caches(); 227 } else { 228 _locked_seen++; 229 } 230 return; 231 } 232 233 if (nm->is_zombie()) { 234 // If it is first time, we see nmethod then we mark it. Otherwise, 235 // we reclame it. When we have seen a zombie method twice, we know that 236 // there are no inline caches that refer to it. 237 if (nm->is_marked_for_reclamation()) { 238 assert(!nm->is_locked_by_vm(), "must not flush locked nmethods"); 239 if (PrintMethodFlushing && Verbose) { 240 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm); 241 } 242 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 243 nm->flush(); 244 } else { 245 if (PrintMethodFlushing && Verbose) { 246 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm); 247 } 248 nm->mark_for_reclamation(); 249 _rescan = true; 250 } 251 } else if (nm->is_not_entrant()) { 252 // If there is no current activations of this method on the 253 // stack we can safely convert it to a zombie method 254 if (nm->can_not_entrant_be_converted()) { 255 if (PrintMethodFlushing && Verbose) { 256 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm); 257 } 258 nm->make_zombie(); 259 _rescan = true; 260 } else { 261 // Still alive, clean up its inline caches 262 MutexLocker cl(CompiledIC_lock); 263 nm->cleanup_inline_caches(); 264 // we coudn't transition this nmethod so don't immediately 265 // request a rescan. If this method stays on the stack for a 266 // long time we don't want to keep rescanning the code cache. 267 _not_entrant_seen_on_stack++; 268 } 269 } else if (nm->is_unloaded()) { 270 // Unloaded code, just make it a zombie 271 if (PrintMethodFlushing && Verbose) 272 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm); 273 if (nm->is_osr_method()) { 274 // No inline caches will ever point to osr methods, so we can just remove it 275 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 276 nm->flush(); 277 } else { 278 nm->make_zombie(); 279 _rescan = true; 280 } 281 } else { 282 assert(nm->is_alive(), "should be alive"); 283 284 if (UseCodeCacheFlushing) { 285 if ((nm->method()->code() != nm) && !(nm->is_locked_by_vm()) && !(nm->is_osr_method()) && 286 (_traversals > _was_full_traversal+2) && (((uint)nm->compile_id()) < _highest_marked) && 287 CodeCache::needs_flushing()) { 288 // This method has not been called since the forced cleanup happened 289 nm->make_not_entrant(); 290 } 291 } 292 293 // Clean-up all inline caches that points to zombie/non-reentrant methods 294 MutexLocker cl(CompiledIC_lock); 295 nm->cleanup_inline_caches(); 296 } 297 } 298 299 // Code cache unloading: when compilers notice the code cache is getting full, 300 // they will call a vm op that comes here. This code attempts to speculatively 301 // unload the oldest half of the nmethods (based on the compile job id) by 302 // saving the old code in a list in the CodeCache. Then 303 // execution resumes. If a method so marked is not called by the second sweeper 304 // stack traversal after the current one, the nmethod will be marked non-entrant and 305 // got rid of by normal sweeping. If the method is called, the methodOop's 306 // _code field is restored and the methodOop/nmethod 307 // go back to their normal state. 308 void NMethodSweeper::handle_full_code_cache(bool is_full) { 309 // Only the first one to notice can advise us to start early cleaning 310 if (!is_full){ 311 jint old = Atomic::cmpxchg( 1, &_advise_to_sweep, 0 ); 312 if (old != 0) { 313 return; 314 } 315 } | 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/nmethod.hpp" 28 #include "compiler/compileBroker.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/methodOop.hpp" 31 #include "runtime/atomic.hpp" 32 #include "runtime/compilationPolicy.hpp" 33 #include "runtime/mutexLocker.hpp" 34 #include "runtime/os.hpp" 35 #include "runtime/sweeper.hpp" 36 #include "runtime/vm_operations.hpp" 37 #include "utilities/events.hpp" 38 #include "utilities/xmlstream.hpp" 39 40 #ifdef ASSERT 41 42 #define SWEEP(nm) record_sweep(nm, __LINE__) 43 // Sweeper logging code 44 class SweeperRecord { 45 public: 46 int traversal; 47 int invocation; 48 int compile_id; 49 long traversal_mark; 50 int state; 51 const char* kind; 52 address vep; 53 address uep; 54 int line; 55 56 void print() { 57 tty->print_cr("traversal = %d invocation = %d compile_id = %d %s uep = " PTR_FORMAT " vep = " 58 PTR_FORMAT " state = %d traversal_mark %d line = %d", 59 traversal, 60 invocation, 61 compile_id, 62 kind == NULL ? "" : kind, 63 uep, 64 vep, 65 state, 66 traversal_mark, 67 line); 68 } 69 }; 70 71 static uint _sweep_index = 0; 72 static SweeperRecord* _records = NULL; 73 74 void NMethodSweeper::report_events(int id, address entry) { 75 if (_records != NULL) { 76 for (uint i = _sweep_index; i < SweeperLogEntries; i++) { 77 if (_records[i].uep == entry || 78 _records[i].vep == entry || 79 _records[i].compile_id == id) { 80 _records[i].print(); 81 } 82 } 83 for (uint i = 0; i < _sweep_index; i++) { 84 if (_records[i].uep == entry || 85 _records[i].vep == entry || 86 _records[i].compile_id == id) { 87 _records[i].print(); 88 } 89 } 90 } 91 } 92 93 void NMethodSweeper::report_events() { 94 if (_records != NULL) { 95 for (uint i = _sweep_index; i < SweeperLogEntries; i++) { 96 // skip empty records 97 if (_records[i].vep == NULL) continue; 98 _records[i].print(); 99 } 100 for (uint i = 0; i < _sweep_index; i++) { 101 // skip empty records 102 if (_records[i].vep == NULL) continue; 103 _records[i].print(); 104 } 105 } 106 } 107 108 void NMethodSweeper::record_sweep(nmethod* nm, int line) { 109 if (_records != NULL) { 110 _records[_sweep_index].traversal = _traversals; 111 _records[_sweep_index].traversal_mark = nm->_stack_traversal_mark; 112 _records[_sweep_index].invocation = _invocations; 113 _records[_sweep_index].compile_id = nm->compile_id(); 114 _records[_sweep_index].kind = nm->compile_kind(); 115 _records[_sweep_index].state = nm->_state; 116 _records[_sweep_index].vep = nm->verified_entry_point(); 117 _records[_sweep_index].uep = nm->entry_point(); 118 _records[_sweep_index].line = line; 119 120 _sweep_index = (_sweep_index + 1) % SweeperLogEntries; 121 } 122 } 123 #else 124 #define SWEEP(nm) 125 #endif 126 127 128 long NMethodSweeper::_traversals = 0; // No. of stack traversals performed 129 nmethod* NMethodSweeper::_current = NULL; // Current nmethod 130 int NMethodSweeper::_seen = 0 ; // No. of nmethods we have currently processed in current pass of CodeCache 131 132 volatile int NMethodSweeper::_invocations = 0; // No. of invocations left until we are completed with this pass 133 volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress. 134 135 jint NMethodSweeper::_locked_seen = 0; 136 jint NMethodSweeper::_not_entrant_seen_on_stack = 0; 137 bool NMethodSweeper::_rescan = false; 138 bool NMethodSweeper::_do_sweep = false; 139 bool NMethodSweeper::_was_full = false; 140 jint NMethodSweeper::_advise_to_sweep = 0; 141 jlong NMethodSweeper::_last_was_full = 0; 142 uint NMethodSweeper::_highest_marked = 0; 143 long NMethodSweeper::_was_full_traversal = 0; 144 145 class MarkActivationClosure: public CodeBlobClosure { 146 public: 147 virtual void do_code_blob(CodeBlob* cb) { 208 // Update the _last_was_full time so we can tell how fast the 209 // code cache is filling up 210 _last_was_full = os::javaTimeMillis(); 211 212 log_sweep("restart_compiler"); 213 } 214 } 215 } 216 } 217 218 void NMethodSweeper::possibly_sweep() { 219 assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode"); 220 if ((!MethodFlushing) || (!_do_sweep)) return; 221 222 if (_invocations > 0) { 223 // Only one thread at a time will sweep 224 jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 ); 225 if (old != 0) { 226 return; 227 } 228 #ifdef ASSERT 229 if (LogSweeper && _records == NULL) { 230 // Create the ring buffer for the logging code 231 _records = NEW_C_HEAP_ARRAY(SweeperRecord, SweeperLogEntries); 232 memset(_records, 0, sizeof(SweeperRecord) * SweeperLogEntries); 233 } 234 #endif 235 if (_invocations > 0) { 236 sweep_code_cache(); 237 _invocations--; 238 } 239 _sweep_started = 0; 240 } 241 } 242 243 void NMethodSweeper::sweep_code_cache() { 244 #ifdef ASSERT 245 jlong sweep_start; 246 if (PrintMethodFlushing) { 247 sweep_start = os::javaTimeMillis(); 248 } 249 #endif 250 if (PrintMethodFlushing && Verbose) { 251 tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations); 252 } 253 254 // We want to visit all nmethods after NmethodSweepFraction 291 // clean them up so just stop scanning. We could scan once more 292 // but that complicates the control logic and it's unlikely to 293 // matter much. 294 if (PrintMethodFlushing) { 295 tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep"); 296 } 297 } 298 299 #ifdef ASSERT 300 if(PrintMethodFlushing) { 301 jlong sweep_end = os::javaTimeMillis(); 302 tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, sweep_end - sweep_start); 303 } 304 #endif 305 306 if (_invocations == 1) { 307 log_sweep("finished"); 308 } 309 } 310 311 class NMethodMarker: public StackObj { 312 private: 313 CompilerThread* _thread; 314 public: 315 NMethodMarker(nmethod* nm) { 316 _thread = CompilerThread::current(); 317 _thread->set_scanned_nmethod(nm); 318 } 319 ~NMethodMarker() { 320 _thread->set_scanned_nmethod(NULL); 321 } 322 }; 323 324 325 void NMethodSweeper::process_nmethod(nmethod *nm) { 326 assert(!CodeCache_lock->owned_by_self(), "just checking"); 327 328 // Make sure this nmethod doesn't get unloaded during the scan, 329 // since the locks acquired below might safepoint. 330 NMethodMarker nmm(nm); 331 332 SWEEP(nm); 333 334 // Skip methods that are currently referenced by the VM 335 if (nm->is_locked_by_vm()) { 336 // But still remember to clean-up inline caches for alive nmethods 337 if (nm->is_alive()) { 338 // Clean-up all inline caches that points to zombie/non-reentrant methods 339 MutexLocker cl(CompiledIC_lock); 340 nm->cleanup_inline_caches(); 341 SWEEP(nm); 342 } else { 343 _locked_seen++; 344 SWEEP(nm); 345 } 346 return; 347 } 348 349 if (nm->is_zombie()) { 350 // If it is first time, we see nmethod then we mark it. Otherwise, 351 // we reclame it. When we have seen a zombie method twice, we know that 352 // there are no inline caches that refer to it. 353 if (nm->is_marked_for_reclamation()) { 354 assert(!nm->is_locked_by_vm(), "must not flush locked nmethods"); 355 if (PrintMethodFlushing && Verbose) { 356 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (marked for reclamation) being flushed", nm->compile_id(), nm); 357 } 358 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 359 nm->flush(); 360 } else { 361 if (PrintMethodFlushing && Verbose) { 362 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm); 363 } 364 nm->mark_for_reclamation(); 365 _rescan = true; 366 SWEEP(nm); 367 } 368 } else if (nm->is_not_entrant()) { 369 // If there is no current activations of this method on the 370 // stack we can safely convert it to a zombie method 371 if (nm->can_not_entrant_be_converted()) { 372 if (PrintMethodFlushing && Verbose) { 373 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm); 374 } 375 nm->make_zombie(); 376 _rescan = true; 377 SWEEP(nm); 378 } else { 379 // Still alive, clean up its inline caches 380 MutexLocker cl(CompiledIC_lock); 381 nm->cleanup_inline_caches(); 382 // we coudn't transition this nmethod so don't immediately 383 // request a rescan. If this method stays on the stack for a 384 // long time we don't want to keep rescanning the code cache. 385 _not_entrant_seen_on_stack++; 386 SWEEP(nm); 387 } 388 } else if (nm->is_unloaded()) { 389 // Unloaded code, just make it a zombie 390 if (PrintMethodFlushing && Verbose) 391 tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (unloaded) being made zombie", nm->compile_id(), nm); 392 if (nm->is_osr_method()) { 393 // No inline caches will ever point to osr methods, so we can just remove it 394 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 395 SWEEP(nm); 396 nm->flush(); 397 } else { 398 nm->make_zombie(); 399 _rescan = true; 400 SWEEP(nm); 401 } 402 } else { 403 assert(nm->is_alive(), "should be alive"); 404 405 if (UseCodeCacheFlushing) { 406 if ((nm->method()->code() != nm) && !(nm->is_locked_by_vm()) && !(nm->is_osr_method()) && 407 (_traversals > _was_full_traversal+2) && (((uint)nm->compile_id()) < _highest_marked) && 408 CodeCache::needs_flushing()) { 409 // This method has not been called since the forced cleanup happened 410 nm->make_not_entrant(); 411 } 412 } 413 414 // Clean-up all inline caches that points to zombie/non-reentrant methods 415 MutexLocker cl(CompiledIC_lock); 416 nm->cleanup_inline_caches(); 417 SWEEP(nm); 418 } 419 } 420 421 // Code cache unloading: when compilers notice the code cache is getting full, 422 // they will call a vm op that comes here. This code attempts to speculatively 423 // unload the oldest half of the nmethods (based on the compile job id) by 424 // saving the old code in a list in the CodeCache. Then 425 // execution resumes. If a method so marked is not called by the second sweeper 426 // stack traversal after the current one, the nmethod will be marked non-entrant and 427 // got rid of by normal sweeping. If the method is called, the methodOop's 428 // _code field is restored and the methodOop/nmethod 429 // go back to their normal state. 430 void NMethodSweeper::handle_full_code_cache(bool is_full) { 431 // Only the first one to notice can advise us to start early cleaning 432 if (!is_full){ 433 jint old = Atomic::cmpxchg( 1, &_advise_to_sweep, 0 ); 434 if (old != 0) { 435 return; 436 } 437 } |