Wed, 02 Feb 2011 11:35:26 -0500
7016023: Enable building ARM and PPC from src/closed repository
Reviewed-by: dholmes, bdelsart
1 /*
2 * Copyright (c) 2001, 2010, 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 */
25 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "runtime/os.hpp"
29 #include "utilities/workgroup.hpp"
31 // Definitions of WorkGang methods.
33 AbstractWorkGang::AbstractWorkGang(const char* name,
34 bool are_GC_task_threads,
35 bool are_ConcurrentGC_threads) :
36 _name(name),
37 _are_GC_task_threads(are_GC_task_threads),
38 _are_ConcurrentGC_threads(are_ConcurrentGC_threads) {
40 assert(!(are_GC_task_threads && are_ConcurrentGC_threads),
41 "They cannot both be STW GC and Concurrent threads" );
43 // Other initialization.
44 _monitor = new Monitor(/* priority */ Mutex::leaf,
45 /* name */ "WorkGroup monitor",
46 /* allow_vm_block */ are_GC_task_threads);
47 assert(monitor() != NULL, "Failed to allocate monitor");
48 _terminate = false;
49 _task = NULL;
50 _sequence_number = 0;
51 _started_workers = 0;
52 _finished_workers = 0;
53 }
55 WorkGang::WorkGang(const char* name,
56 int workers,
57 bool are_GC_task_threads,
58 bool are_ConcurrentGC_threads) :
59 AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) {
60 // Save arguments.
61 _total_workers = workers;
62 }
64 GangWorker* WorkGang::allocate_worker(int which) {
65 GangWorker* new_worker = new GangWorker(this, which);
66 return new_worker;
67 }
69 // The current implementation will exit if the allocation
70 // of any worker fails. Still, return a boolean so that
71 // a future implementation can possibly do a partial
72 // initialization of the workers and report such to the
73 // caller.
74 bool WorkGang::initialize_workers() {
76 if (TraceWorkGang) {
77 tty->print_cr("Constructing work gang %s with %d threads",
78 name(),
79 total_workers());
80 }
81 _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, total_workers());
82 if (gang_workers() == NULL) {
83 vm_exit_out_of_memory(0, "Cannot create GangWorker array.");
84 return false;
85 }
86 os::ThreadType worker_type;
87 if (are_ConcurrentGC_threads()) {
88 worker_type = os::cgc_thread;
89 } else {
90 worker_type = os::pgc_thread;
91 }
92 for (int worker = 0; worker < total_workers(); worker += 1) {
93 GangWorker* new_worker = allocate_worker(worker);
94 assert(new_worker != NULL, "Failed to allocate GangWorker");
95 _gang_workers[worker] = new_worker;
96 if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) {
97 vm_exit_out_of_memory(0, "Cannot create worker GC thread. Out of system resources.");
98 return false;
99 }
100 if (!DisableStartThread) {
101 os::start_thread(new_worker);
102 }
103 }
104 return true;
105 }
107 AbstractWorkGang::~AbstractWorkGang() {
108 if (TraceWorkGang) {
109 tty->print_cr("Destructing work gang %s", name());
110 }
111 stop(); // stop all the workers
112 for (int worker = 0; worker < total_workers(); worker += 1) {
113 delete gang_worker(worker);
114 }
115 delete gang_workers();
116 delete monitor();
117 }
119 GangWorker* AbstractWorkGang::gang_worker(int i) const {
120 // Array index bounds checking.
121 GangWorker* result = NULL;
122 assert(gang_workers() != NULL, "No workers for indexing");
123 assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds");
124 result = _gang_workers[i];
125 assert(result != NULL, "Indexing to null worker");
126 return result;
127 }
129 void WorkGang::run_task(AbstractGangTask* task) {
130 // This thread is executed by the VM thread which does not block
131 // on ordinary MutexLocker's.
132 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
133 if (TraceWorkGang) {
134 tty->print_cr("Running work gang %s task %s", name(), task->name());
135 }
136 // Tell all the workers to run a task.
137 assert(task != NULL, "Running a null task");
138 // Initialize.
139 _task = task;
140 _sequence_number += 1;
141 _started_workers = 0;
142 _finished_workers = 0;
143 // Tell the workers to get to work.
144 monitor()->notify_all();
145 // Wait for them to be finished
146 while (finished_workers() < total_workers()) {
147 if (TraceWorkGang) {
148 tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d",
149 name(), finished_workers(), total_workers(),
150 _sequence_number);
151 }
152 monitor()->wait(/* no_safepoint_check */ true);
153 }
154 _task = NULL;
155 if (TraceWorkGang) {
156 tty->print_cr("/nFinished work gang %s: %d/%d sequence %d",
157 name(), finished_workers(), total_workers(),
158 _sequence_number);
159 }
160 }
162 void AbstractWorkGang::stop() {
163 // Tell all workers to terminate, then wait for them to become inactive.
164 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
165 if (TraceWorkGang) {
166 tty->print_cr("Stopping work gang %s task %s", name(), task()->name());
167 }
168 _task = NULL;
169 _terminate = true;
170 monitor()->notify_all();
171 while (finished_workers() < total_workers()) {
172 if (TraceWorkGang) {
173 tty->print_cr("Waiting in work gang %s: %d/%d finished",
174 name(), finished_workers(), total_workers());
175 }
176 monitor()->wait(/* no_safepoint_check */ true);
177 }
178 }
180 void AbstractWorkGang::internal_worker_poll(WorkData* data) const {
181 assert(monitor()->owned_by_self(), "worker_poll is an internal method");
182 assert(data != NULL, "worker data is null");
183 data->set_terminate(terminate());
184 data->set_task(task());
185 data->set_sequence_number(sequence_number());
186 }
188 void AbstractWorkGang::internal_note_start() {
189 assert(monitor()->owned_by_self(), "note_finish is an internal method");
190 _started_workers += 1;
191 }
193 void AbstractWorkGang::internal_note_finish() {
194 assert(monitor()->owned_by_self(), "note_finish is an internal method");
195 _finished_workers += 1;
196 }
198 void AbstractWorkGang::print_worker_threads_on(outputStream* st) const {
199 uint num_thr = total_workers();
200 for (uint i = 0; i < num_thr; i++) {
201 gang_worker(i)->print_on(st);
202 st->cr();
203 }
204 }
206 void AbstractWorkGang::threads_do(ThreadClosure* tc) const {
207 assert(tc != NULL, "Null ThreadClosure");
208 uint num_thr = total_workers();
209 for (uint i = 0; i < num_thr; i++) {
210 tc->do_thread(gang_worker(i));
211 }
212 }
214 // GangWorker methods.
216 GangWorker::GangWorker(AbstractWorkGang* gang, uint id) {
217 _gang = gang;
218 set_id(id);
219 set_name("Gang worker#%d (%s)", id, gang->name());
220 }
222 void GangWorker::run() {
223 initialize();
224 loop();
225 }
227 void GangWorker::initialize() {
228 this->initialize_thread_local_storage();
229 assert(_gang != NULL, "No gang to run in");
230 os::set_priority(this, NearMaxPriority);
231 if (TraceWorkGang) {
232 tty->print_cr("Running gang worker for gang %s id %d",
233 gang()->name(), id());
234 }
235 // The VM thread should not execute here because MutexLocker's are used
236 // as (opposed to MutexLockerEx's).
237 assert(!Thread::current()->is_VM_thread(), "VM thread should not be part"
238 " of a work gang");
239 }
241 void GangWorker::loop() {
242 int previous_sequence_number = 0;
243 Monitor* gang_monitor = gang()->monitor();
244 for ( ; /* !terminate() */; ) {
245 WorkData data;
246 int part; // Initialized below.
247 {
248 // Grab the gang mutex.
249 MutexLocker ml(gang_monitor);
250 // Wait for something to do.
251 // Polling outside the while { wait } avoids missed notifies
252 // in the outer loop.
253 gang()->internal_worker_poll(&data);
254 if (TraceWorkGang) {
255 tty->print("Polled outside for work in gang %s worker %d",
256 gang()->name(), id());
257 tty->print(" terminate: %s",
258 data.terminate() ? "true" : "false");
259 tty->print(" sequence: %d (prev: %d)",
260 data.sequence_number(), previous_sequence_number);
261 if (data.task() != NULL) {
262 tty->print(" task: %s", data.task()->name());
263 } else {
264 tty->print(" task: NULL");
265 }
266 tty->cr();
267 }
268 for ( ; /* break or return */; ) {
269 // Terminate if requested.
270 if (data.terminate()) {
271 gang()->internal_note_finish();
272 gang_monitor->notify_all();
273 return;
274 }
275 // Check for new work.
276 if ((data.task() != NULL) &&
277 (data.sequence_number() != previous_sequence_number)) {
278 gang()->internal_note_start();
279 gang_monitor->notify_all();
280 part = gang()->started_workers() - 1;
281 break;
282 }
283 // Nothing to do.
284 gang_monitor->wait(/* no_safepoint_check */ true);
285 gang()->internal_worker_poll(&data);
286 if (TraceWorkGang) {
287 tty->print("Polled inside for work in gang %s worker %d",
288 gang()->name(), id());
289 tty->print(" terminate: %s",
290 data.terminate() ? "true" : "false");
291 tty->print(" sequence: %d (prev: %d)",
292 data.sequence_number(), previous_sequence_number);
293 if (data.task() != NULL) {
294 tty->print(" task: %s", data.task()->name());
295 } else {
296 tty->print(" task: NULL");
297 }
298 tty->cr();
299 }
300 }
301 // Drop gang mutex.
302 }
303 if (TraceWorkGang) {
304 tty->print("Work for work gang %s id %d task %s part %d",
305 gang()->name(), id(), data.task()->name(), part);
306 }
307 assert(data.task() != NULL, "Got null task");
308 data.task()->work(part);
309 {
310 if (TraceWorkGang) {
311 tty->print("Finish for work gang %s id %d task %s part %d",
312 gang()->name(), id(), data.task()->name(), part);
313 }
314 // Grab the gang mutex.
315 MutexLocker ml(gang_monitor);
316 gang()->internal_note_finish();
317 // Tell the gang you are done.
318 gang_monitor->notify_all();
319 // Drop the gang mutex.
320 }
321 previous_sequence_number = data.sequence_number();
322 }
323 }
325 bool GangWorker::is_GC_task_thread() const {
326 return gang()->are_GC_task_threads();
327 }
329 bool GangWorker::is_ConcurrentGC_thread() const {
330 return gang()->are_ConcurrentGC_threads();
331 }
333 void GangWorker::print_on(outputStream* st) const {
334 st->print("\"%s\" ", name());
335 Thread::print_on(st);
336 st->cr();
337 }
339 // Printing methods
341 const char* AbstractWorkGang::name() const {
342 return _name;
343 }
345 #ifndef PRODUCT
347 const char* AbstractGangTask::name() const {
348 return _name;
349 }
351 #endif /* PRODUCT */
353 // *** WorkGangBarrierSync
355 WorkGangBarrierSync::WorkGangBarrierSync()
356 : _monitor(Mutex::safepoint, "work gang barrier sync", true),
357 _n_workers(0), _n_completed(0), _should_reset(false) {
358 }
360 WorkGangBarrierSync::WorkGangBarrierSync(int n_workers, const char* name)
361 : _monitor(Mutex::safepoint, name, true),
362 _n_workers(n_workers), _n_completed(0), _should_reset(false) {
363 }
365 void WorkGangBarrierSync::set_n_workers(int n_workers) {
366 _n_workers = n_workers;
367 _n_completed = 0;
368 _should_reset = false;
369 }
371 void WorkGangBarrierSync::enter() {
372 MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
373 if (should_reset()) {
374 // The should_reset() was set and we are the first worker to enter
375 // the sync barrier. We will zero the n_completed() count which
376 // effectively resets the barrier.
377 zero_completed();
378 set_should_reset(false);
379 }
380 inc_completed();
381 if (n_completed() == n_workers()) {
382 // At this point we would like to reset the barrier to be ready in
383 // case it is used again. However, we cannot set n_completed() to
384 // 0, even after the notify_all(), given that some other workers
385 // might still be waiting for n_completed() to become ==
386 // n_workers(). So, if we set n_completed() to 0, those workers
387 // will get stuck (as they will wake up, see that n_completed() !=
388 // n_workers() and go back to sleep). Instead, we raise the
389 // should_reset() flag and the barrier will be reset the first
390 // time a worker enters it again.
391 set_should_reset(true);
392 monitor()->notify_all();
393 } else {
394 while (n_completed() != n_workers()) {
395 monitor()->wait(/* no_safepoint_check */ true);
396 }
397 }
398 }
400 // SubTasksDone functions.
402 SubTasksDone::SubTasksDone(int n) :
403 _n_tasks(n), _n_threads(1), _tasks(NULL) {
404 _tasks = NEW_C_HEAP_ARRAY(jint, n);
405 guarantee(_tasks != NULL, "alloc failure");
406 clear();
407 }
409 bool SubTasksDone::valid() {
410 return _tasks != NULL;
411 }
413 void SubTasksDone::set_n_threads(int t) {
414 #ifdef ASSERT
415 assert(_claimed == 0 || _threads_completed == _n_threads,
416 "should not be called while tasks are being processed!");
417 #endif
418 _n_threads = (t == 0 ? 1 : t);
419 }
421 void SubTasksDone::clear() {
422 for (int i = 0; i < _n_tasks; i++) {
423 _tasks[i] = 0;
424 }
425 _threads_completed = 0;
426 #ifdef ASSERT
427 _claimed = 0;
428 #endif
429 }
431 bool SubTasksDone::is_task_claimed(int t) {
432 assert(0 <= t && t < _n_tasks, "bad task id.");
433 jint old = _tasks[t];
434 if (old == 0) {
435 old = Atomic::cmpxchg(1, &_tasks[t], 0);
436 }
437 assert(_tasks[t] == 1, "What else?");
438 bool res = old != 0;
439 #ifdef ASSERT
440 if (!res) {
441 assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?");
442 Atomic::inc(&_claimed);
443 }
444 #endif
445 return res;
446 }
448 void SubTasksDone::all_tasks_completed() {
449 jint observed = _threads_completed;
450 jint old;
451 do {
452 old = observed;
453 observed = Atomic::cmpxchg(old+1, &_threads_completed, old);
454 } while (observed != old);
455 // If this was the last thread checking in, clear the tasks.
456 if (observed+1 == _n_threads) clear();
457 }
460 SubTasksDone::~SubTasksDone() {
461 if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks);
462 }
464 // *** SequentialSubTasksDone
466 void SequentialSubTasksDone::clear() {
467 _n_tasks = _n_claimed = 0;
468 _n_threads = _n_completed = 0;
469 }
471 bool SequentialSubTasksDone::valid() {
472 return _n_threads > 0;
473 }
475 bool SequentialSubTasksDone::is_task_claimed(int& t) {
476 jint* n_claimed_ptr = &_n_claimed;
477 t = *n_claimed_ptr;
478 while (t < _n_tasks) {
479 jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t);
480 if (res == t) {
481 return false;
482 }
483 t = *n_claimed_ptr;
484 }
485 return true;
486 }
488 bool SequentialSubTasksDone::all_tasks_completed() {
489 jint* n_completed_ptr = &_n_completed;
490 jint complete = *n_completed_ptr;
491 while (true) {
492 jint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete);
493 if (res == complete) {
494 break;
495 }
496 complete = res;
497 }
498 if (complete+1 == _n_threads) {
499 clear();
500 return true;
501 }
502 return false;
503 }
505 bool FreeIdSet::_stat_init = false;
506 FreeIdSet* FreeIdSet::_sets[NSets];
507 bool FreeIdSet::_safepoint;
509 FreeIdSet::FreeIdSet(int sz, Monitor* mon) :
510 _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0)
511 {
512 _ids = new int[sz];
513 for (int i = 0; i < sz; i++) _ids[i] = i+1;
514 _ids[sz-1] = end_of_list; // end of list.
515 if (_stat_init) {
516 for (int j = 0; j < NSets; j++) _sets[j] = NULL;
517 _stat_init = true;
518 }
519 // Add to sets. (This should happen while the system is still single-threaded.)
520 for (int j = 0; j < NSets; j++) {
521 if (_sets[j] == NULL) {
522 _sets[j] = this;
523 _index = j;
524 break;
525 }
526 }
527 guarantee(_index != -1, "Too many FreeIdSets in use!");
528 }
530 FreeIdSet::~FreeIdSet() {
531 _sets[_index] = NULL;
532 }
534 void FreeIdSet::set_safepoint(bool b) {
535 _safepoint = b;
536 if (b) {
537 for (int j = 0; j < NSets; j++) {
538 if (_sets[j] != NULL && _sets[j]->_waiters > 0) {
539 Monitor* mon = _sets[j]->_mon;
540 mon->lock_without_safepoint_check();
541 mon->notify_all();
542 mon->unlock();
543 }
544 }
545 }
546 }
548 #define FID_STATS 0
550 int FreeIdSet::claim_par_id() {
551 #if FID_STATS
552 thread_t tslf = thr_self();
553 tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed);
554 #endif
555 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
556 while (!_safepoint && _hd == end_of_list) {
557 _waiters++;
558 #if FID_STATS
559 if (_waiters > 5) {
560 tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n",
561 tslf, _waiters, _claimed);
562 }
563 #endif
564 _mon->wait(Mutex::_no_safepoint_check_flag);
565 _waiters--;
566 }
567 if (_hd == end_of_list) {
568 #if FID_STATS
569 tty->print("claim_par_id[%d]: returning EOL.\n", tslf);
570 #endif
571 return -1;
572 } else {
573 int res = _hd;
574 _hd = _ids[res];
575 _ids[res] = claimed; // For debugging.
576 _claimed++;
577 #if FID_STATS
578 tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n",
579 tslf, res, _claimed);
580 #endif
581 return res;
582 }
583 }
585 bool FreeIdSet::claim_perm_id(int i) {
586 assert(0 <= i && i < _sz, "Out of range.");
587 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
588 int prev = end_of_list;
589 int cur = _hd;
590 while (cur != end_of_list) {
591 if (cur == i) {
592 if (prev == end_of_list) {
593 _hd = _ids[cur];
594 } else {
595 _ids[prev] = _ids[cur];
596 }
597 _ids[cur] = claimed;
598 _claimed++;
599 return true;
600 } else {
601 prev = cur;
602 cur = _ids[cur];
603 }
604 }
605 return false;
607 }
609 void FreeIdSet::release_par_id(int id) {
610 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
611 assert(_ids[id] == claimed, "Precondition.");
612 _ids[id] = _hd;
613 _hd = id;
614 _claimed--;
615 #if FID_STATS
616 tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n",
617 thr_self(), id, _waiters, _claimed);
618 #endif
619 if (_waiters > 0)
620 // Notify all would be safer, but this is OK, right?
621 _mon->notify_all();
622 }