1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/utilities/workgroup.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,653 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "memory/allocation.hpp"
1.30 +#include "memory/allocation.inline.hpp"
1.31 +#include "runtime/os.hpp"
1.32 +#include "utilities/workgroup.hpp"
1.33 +
1.34 +PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
1.35 +
1.36 +// Definitions of WorkGang methods.
1.37 +
1.38 +AbstractWorkGang::AbstractWorkGang(const char* name,
1.39 + bool are_GC_task_threads,
1.40 + bool are_ConcurrentGC_threads) :
1.41 + _name(name),
1.42 + _are_GC_task_threads(are_GC_task_threads),
1.43 + _are_ConcurrentGC_threads(are_ConcurrentGC_threads) {
1.44 +
1.45 + assert(!(are_GC_task_threads && are_ConcurrentGC_threads),
1.46 + "They cannot both be STW GC and Concurrent threads" );
1.47 +
1.48 + // Other initialization.
1.49 + _monitor = new Monitor(/* priority */ Mutex::leaf,
1.50 + /* name */ "WorkGroup monitor",
1.51 + /* allow_vm_block */ are_GC_task_threads);
1.52 + assert(monitor() != NULL, "Failed to allocate monitor");
1.53 + _terminate = false;
1.54 + _task = NULL;
1.55 + _sequence_number = 0;
1.56 + _started_workers = 0;
1.57 + _finished_workers = 0;
1.58 +}
1.59 +
1.60 +WorkGang::WorkGang(const char* name,
1.61 + uint workers,
1.62 + bool are_GC_task_threads,
1.63 + bool are_ConcurrentGC_threads) :
1.64 + AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) {
1.65 + _total_workers = workers;
1.66 +}
1.67 +
1.68 +GangWorker* WorkGang::allocate_worker(uint which) {
1.69 + GangWorker* new_worker = new GangWorker(this, which);
1.70 + return new_worker;
1.71 +}
1.72 +
1.73 +// The current implementation will exit if the allocation
1.74 +// of any worker fails. Still, return a boolean so that
1.75 +// a future implementation can possibly do a partial
1.76 +// initialization of the workers and report such to the
1.77 +// caller.
1.78 +bool WorkGang::initialize_workers() {
1.79 +
1.80 + if (TraceWorkGang) {
1.81 + tty->print_cr("Constructing work gang %s with %d threads",
1.82 + name(),
1.83 + total_workers());
1.84 + }
1.85 + _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, total_workers(), mtInternal);
1.86 + if (gang_workers() == NULL) {
1.87 + vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GangWorker array.");
1.88 + return false;
1.89 + }
1.90 + os::ThreadType worker_type;
1.91 + if (are_ConcurrentGC_threads()) {
1.92 + worker_type = os::cgc_thread;
1.93 + } else {
1.94 + worker_type = os::pgc_thread;
1.95 + }
1.96 + for (uint worker = 0; worker < total_workers(); worker += 1) {
1.97 + GangWorker* new_worker = allocate_worker(worker);
1.98 + assert(new_worker != NULL, "Failed to allocate GangWorker");
1.99 + _gang_workers[worker] = new_worker;
1.100 + if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) {
1.101 + vm_exit_out_of_memory(0, OOM_MALLOC_ERROR,
1.102 + "Cannot create worker GC thread. Out of system resources.");
1.103 + return false;
1.104 + }
1.105 + if (!DisableStartThread) {
1.106 + os::start_thread(new_worker);
1.107 + }
1.108 + }
1.109 + return true;
1.110 +}
1.111 +
1.112 +AbstractWorkGang::~AbstractWorkGang() {
1.113 + if (TraceWorkGang) {
1.114 + tty->print_cr("Destructing work gang %s", name());
1.115 + }
1.116 + stop(); // stop all the workers
1.117 + for (uint worker = 0; worker < total_workers(); worker += 1) {
1.118 + delete gang_worker(worker);
1.119 + }
1.120 + delete gang_workers();
1.121 + delete monitor();
1.122 +}
1.123 +
1.124 +GangWorker* AbstractWorkGang::gang_worker(uint i) const {
1.125 + // Array index bounds checking.
1.126 + GangWorker* result = NULL;
1.127 + assert(gang_workers() != NULL, "No workers for indexing");
1.128 + assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds");
1.129 + result = _gang_workers[i];
1.130 + assert(result != NULL, "Indexing to null worker");
1.131 + return result;
1.132 +}
1.133 +
1.134 +void WorkGang::run_task(AbstractGangTask* task) {
1.135 + run_task(task, total_workers());
1.136 +}
1.137 +
1.138 +void WorkGang::run_task(AbstractGangTask* task, uint no_of_parallel_workers) {
1.139 + task->set_for_termination(no_of_parallel_workers);
1.140 +
1.141 + // This thread is executed by the VM thread which does not block
1.142 + // on ordinary MutexLocker's.
1.143 + MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
1.144 + if (TraceWorkGang) {
1.145 + tty->print_cr("Running work gang %s task %s", name(), task->name());
1.146 + }
1.147 + // Tell all the workers to run a task.
1.148 + assert(task != NULL, "Running a null task");
1.149 + // Initialize.
1.150 + _task = task;
1.151 + _sequence_number += 1;
1.152 + _started_workers = 0;
1.153 + _finished_workers = 0;
1.154 + // Tell the workers to get to work.
1.155 + monitor()->notify_all();
1.156 + // Wait for them to be finished
1.157 + while (finished_workers() < no_of_parallel_workers) {
1.158 + if (TraceWorkGang) {
1.159 + tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d",
1.160 + name(), finished_workers(), no_of_parallel_workers,
1.161 + _sequence_number);
1.162 + }
1.163 + monitor()->wait(/* no_safepoint_check */ true);
1.164 + }
1.165 + _task = NULL;
1.166 + if (TraceWorkGang) {
1.167 + tty->print_cr("\nFinished work gang %s: %d/%d sequence %d",
1.168 + name(), finished_workers(), no_of_parallel_workers,
1.169 + _sequence_number);
1.170 + Thread* me = Thread::current();
1.171 + tty->print_cr(" T: 0x%x VM_thread: %d", me, me->is_VM_thread());
1.172 + }
1.173 +}
1.174 +
1.175 +void FlexibleWorkGang::run_task(AbstractGangTask* task) {
1.176 + // If active_workers() is passed, _finished_workers
1.177 + // must only be incremented for workers that find non_null
1.178 + // work (as opposed to all those that just check that the
1.179 + // task is not null).
1.180 + WorkGang::run_task(task, (uint) active_workers());
1.181 +}
1.182 +
1.183 +void AbstractWorkGang::stop() {
1.184 + // Tell all workers to terminate, then wait for them to become inactive.
1.185 + MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
1.186 + if (TraceWorkGang) {
1.187 + tty->print_cr("Stopping work gang %s task %s", name(), task()->name());
1.188 + }
1.189 + _task = NULL;
1.190 + _terminate = true;
1.191 + monitor()->notify_all();
1.192 + while (finished_workers() < active_workers()) {
1.193 + if (TraceWorkGang) {
1.194 + tty->print_cr("Waiting in work gang %s: %d/%d finished",
1.195 + name(), finished_workers(), active_workers());
1.196 + }
1.197 + monitor()->wait(/* no_safepoint_check */ true);
1.198 + }
1.199 +}
1.200 +
1.201 +void AbstractWorkGang::internal_worker_poll(WorkData* data) const {
1.202 + assert(monitor()->owned_by_self(), "worker_poll is an internal method");
1.203 + assert(data != NULL, "worker data is null");
1.204 + data->set_terminate(terminate());
1.205 + data->set_task(task());
1.206 + data->set_sequence_number(sequence_number());
1.207 +}
1.208 +
1.209 +void AbstractWorkGang::internal_note_start() {
1.210 + assert(monitor()->owned_by_self(), "note_finish is an internal method");
1.211 + _started_workers += 1;
1.212 +}
1.213 +
1.214 +void AbstractWorkGang::internal_note_finish() {
1.215 + assert(monitor()->owned_by_self(), "note_finish is an internal method");
1.216 + _finished_workers += 1;
1.217 +}
1.218 +
1.219 +void AbstractWorkGang::print_worker_threads_on(outputStream* st) const {
1.220 + uint num_thr = total_workers();
1.221 + for (uint i = 0; i < num_thr; i++) {
1.222 + gang_worker(i)->print_on(st);
1.223 + st->cr();
1.224 + }
1.225 +}
1.226 +
1.227 +void AbstractWorkGang::threads_do(ThreadClosure* tc) const {
1.228 + assert(tc != NULL, "Null ThreadClosure");
1.229 + uint num_thr = total_workers();
1.230 + for (uint i = 0; i < num_thr; i++) {
1.231 + tc->do_thread(gang_worker(i));
1.232 + }
1.233 +}
1.234 +
1.235 +// GangWorker methods.
1.236 +
1.237 +GangWorker::GangWorker(AbstractWorkGang* gang, uint id) {
1.238 + _gang = gang;
1.239 + set_id(id);
1.240 + set_name("Gang worker#%d (%s)", id, gang->name());
1.241 +}
1.242 +
1.243 +void GangWorker::run() {
1.244 + initialize();
1.245 + loop();
1.246 +}
1.247 +
1.248 +void GangWorker::initialize() {
1.249 + this->initialize_thread_local_storage();
1.250 + this->record_stack_base_and_size();
1.251 + assert(_gang != NULL, "No gang to run in");
1.252 + os::set_priority(this, NearMaxPriority);
1.253 + if (TraceWorkGang) {
1.254 + tty->print_cr("Running gang worker for gang %s id %d",
1.255 + gang()->name(), id());
1.256 + }
1.257 + // The VM thread should not execute here because MutexLocker's are used
1.258 + // as (opposed to MutexLockerEx's).
1.259 + assert(!Thread::current()->is_VM_thread(), "VM thread should not be part"
1.260 + " of a work gang");
1.261 +}
1.262 +
1.263 +void GangWorker::loop() {
1.264 + int previous_sequence_number = 0;
1.265 + Monitor* gang_monitor = gang()->monitor();
1.266 + for ( ; /* !terminate() */; ) {
1.267 + WorkData data;
1.268 + int part; // Initialized below.
1.269 + {
1.270 + // Grab the gang mutex.
1.271 + MutexLocker ml(gang_monitor);
1.272 + // Wait for something to do.
1.273 + // Polling outside the while { wait } avoids missed notifies
1.274 + // in the outer loop.
1.275 + gang()->internal_worker_poll(&data);
1.276 + if (TraceWorkGang) {
1.277 + tty->print("Polled outside for work in gang %s worker %d",
1.278 + gang()->name(), id());
1.279 + tty->print(" terminate: %s",
1.280 + data.terminate() ? "true" : "false");
1.281 + tty->print(" sequence: %d (prev: %d)",
1.282 + data.sequence_number(), previous_sequence_number);
1.283 + if (data.task() != NULL) {
1.284 + tty->print(" task: %s", data.task()->name());
1.285 + } else {
1.286 + tty->print(" task: NULL");
1.287 + }
1.288 + tty->cr();
1.289 + }
1.290 + for ( ; /* break or return */; ) {
1.291 + // Terminate if requested.
1.292 + if (data.terminate()) {
1.293 + gang()->internal_note_finish();
1.294 + gang_monitor->notify_all();
1.295 + return;
1.296 + }
1.297 + // Check for new work.
1.298 + if ((data.task() != NULL) &&
1.299 + (data.sequence_number() != previous_sequence_number)) {
1.300 + if (gang()->needs_more_workers()) {
1.301 + gang()->internal_note_start();
1.302 + gang_monitor->notify_all();
1.303 + part = gang()->started_workers() - 1;
1.304 + break;
1.305 + }
1.306 + }
1.307 + // Nothing to do.
1.308 + gang_monitor->wait(/* no_safepoint_check */ true);
1.309 + gang()->internal_worker_poll(&data);
1.310 + if (TraceWorkGang) {
1.311 + tty->print("Polled inside for work in gang %s worker %d",
1.312 + gang()->name(), id());
1.313 + tty->print(" terminate: %s",
1.314 + data.terminate() ? "true" : "false");
1.315 + tty->print(" sequence: %d (prev: %d)",
1.316 + data.sequence_number(), previous_sequence_number);
1.317 + if (data.task() != NULL) {
1.318 + tty->print(" task: %s", data.task()->name());
1.319 + } else {
1.320 + tty->print(" task: NULL");
1.321 + }
1.322 + tty->cr();
1.323 + }
1.324 + }
1.325 + // Drop gang mutex.
1.326 + }
1.327 + if (TraceWorkGang) {
1.328 + tty->print("Work for work gang %s id %d task %s part %d",
1.329 + gang()->name(), id(), data.task()->name(), part);
1.330 + }
1.331 + assert(data.task() != NULL, "Got null task");
1.332 + data.task()->work(part);
1.333 + {
1.334 + if (TraceWorkGang) {
1.335 + tty->print("Finish for work gang %s id %d task %s part %d",
1.336 + gang()->name(), id(), data.task()->name(), part);
1.337 + }
1.338 + // Grab the gang mutex.
1.339 + MutexLocker ml(gang_monitor);
1.340 + gang()->internal_note_finish();
1.341 + // Tell the gang you are done.
1.342 + gang_monitor->notify_all();
1.343 + // Drop the gang mutex.
1.344 + }
1.345 + previous_sequence_number = data.sequence_number();
1.346 + }
1.347 +}
1.348 +
1.349 +bool GangWorker::is_GC_task_thread() const {
1.350 + return gang()->are_GC_task_threads();
1.351 +}
1.352 +
1.353 +bool GangWorker::is_ConcurrentGC_thread() const {
1.354 + return gang()->are_ConcurrentGC_threads();
1.355 +}
1.356 +
1.357 +void GangWorker::print_on(outputStream* st) const {
1.358 + st->print("\"%s\" ", name());
1.359 + Thread::print_on(st);
1.360 + st->cr();
1.361 +}
1.362 +
1.363 +// Printing methods
1.364 +
1.365 +const char* AbstractWorkGang::name() const {
1.366 + return _name;
1.367 +}
1.368 +
1.369 +#ifndef PRODUCT
1.370 +
1.371 +const char* AbstractGangTask::name() const {
1.372 + return _name;
1.373 +}
1.374 +
1.375 +#endif /* PRODUCT */
1.376 +
1.377 +// FlexibleWorkGang
1.378 +
1.379 +
1.380 +// *** WorkGangBarrierSync
1.381 +
1.382 +WorkGangBarrierSync::WorkGangBarrierSync()
1.383 + : _monitor(Mutex::safepoint, "work gang barrier sync", true),
1.384 + _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) {
1.385 +}
1.386 +
1.387 +WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name)
1.388 + : _monitor(Mutex::safepoint, name, true),
1.389 + _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) {
1.390 +}
1.391 +
1.392 +void WorkGangBarrierSync::set_n_workers(uint n_workers) {
1.393 + _n_workers = n_workers;
1.394 + _n_completed = 0;
1.395 + _should_reset = false;
1.396 + _aborted = false;
1.397 +}
1.398 +
1.399 +bool WorkGangBarrierSync::enter() {
1.400 + MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
1.401 + if (should_reset()) {
1.402 + // The should_reset() was set and we are the first worker to enter
1.403 + // the sync barrier. We will zero the n_completed() count which
1.404 + // effectively resets the barrier.
1.405 + zero_completed();
1.406 + set_should_reset(false);
1.407 + }
1.408 + inc_completed();
1.409 + if (n_completed() == n_workers()) {
1.410 + // At this point we would like to reset the barrier to be ready in
1.411 + // case it is used again. However, we cannot set n_completed() to
1.412 + // 0, even after the notify_all(), given that some other workers
1.413 + // might still be waiting for n_completed() to become ==
1.414 + // n_workers(). So, if we set n_completed() to 0, those workers
1.415 + // will get stuck (as they will wake up, see that n_completed() !=
1.416 + // n_workers() and go back to sleep). Instead, we raise the
1.417 + // should_reset() flag and the barrier will be reset the first
1.418 + // time a worker enters it again.
1.419 + set_should_reset(true);
1.420 + monitor()->notify_all();
1.421 + } else {
1.422 + while (n_completed() != n_workers() && !aborted()) {
1.423 + monitor()->wait(/* no_safepoint_check */ true);
1.424 + }
1.425 + }
1.426 + return !aborted();
1.427 +}
1.428 +
1.429 +void WorkGangBarrierSync::abort() {
1.430 + MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
1.431 + set_aborted();
1.432 + monitor()->notify_all();
1.433 +}
1.434 +
1.435 +// SubTasksDone functions.
1.436 +
1.437 +SubTasksDone::SubTasksDone(uint n) :
1.438 + _n_tasks(n), _n_threads(1), _tasks(NULL) {
1.439 + _tasks = NEW_C_HEAP_ARRAY(uint, n, mtInternal);
1.440 + guarantee(_tasks != NULL, "alloc failure");
1.441 + clear();
1.442 +}
1.443 +
1.444 +bool SubTasksDone::valid() {
1.445 + return _tasks != NULL;
1.446 +}
1.447 +
1.448 +void SubTasksDone::set_n_threads(uint t) {
1.449 + assert(_claimed == 0 || _threads_completed == _n_threads,
1.450 + "should not be called while tasks are being processed!");
1.451 + _n_threads = (t == 0 ? 1 : t);
1.452 +}
1.453 +
1.454 +void SubTasksDone::clear() {
1.455 + for (uint i = 0; i < _n_tasks; i++) {
1.456 + _tasks[i] = 0;
1.457 + }
1.458 + _threads_completed = 0;
1.459 +#ifdef ASSERT
1.460 + _claimed = 0;
1.461 +#endif
1.462 +}
1.463 +
1.464 +bool SubTasksDone::is_task_claimed(uint t) {
1.465 + assert(0 <= t && t < _n_tasks, "bad task id.");
1.466 + uint old = _tasks[t];
1.467 + if (old == 0) {
1.468 + old = Atomic::cmpxchg(1, &_tasks[t], 0);
1.469 + }
1.470 + assert(_tasks[t] == 1, "What else?");
1.471 + bool res = old != 0;
1.472 +#ifdef ASSERT
1.473 + if (!res) {
1.474 + assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?");
1.475 + Atomic::inc((volatile jint*) &_claimed);
1.476 + }
1.477 +#endif
1.478 + return res;
1.479 +}
1.480 +
1.481 +void SubTasksDone::all_tasks_completed() {
1.482 + jint observed = _threads_completed;
1.483 + jint old;
1.484 + do {
1.485 + old = observed;
1.486 + observed = Atomic::cmpxchg(old+1, &_threads_completed, old);
1.487 + } while (observed != old);
1.488 + // If this was the last thread checking in, clear the tasks.
1.489 + if (observed+1 == (jint)_n_threads) clear();
1.490 +}
1.491 +
1.492 +
1.493 +SubTasksDone::~SubTasksDone() {
1.494 + if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks, mtInternal);
1.495 +}
1.496 +
1.497 +// *** SequentialSubTasksDone
1.498 +
1.499 +void SequentialSubTasksDone::clear() {
1.500 + _n_tasks = _n_claimed = 0;
1.501 + _n_threads = _n_completed = 0;
1.502 +}
1.503 +
1.504 +bool SequentialSubTasksDone::valid() {
1.505 + return _n_threads > 0;
1.506 +}
1.507 +
1.508 +bool SequentialSubTasksDone::is_task_claimed(uint& t) {
1.509 + uint* n_claimed_ptr = &_n_claimed;
1.510 + t = *n_claimed_ptr;
1.511 + while (t < _n_tasks) {
1.512 + jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t);
1.513 + if (res == (jint)t) {
1.514 + return false;
1.515 + }
1.516 + t = *n_claimed_ptr;
1.517 + }
1.518 + return true;
1.519 +}
1.520 +
1.521 +bool SequentialSubTasksDone::all_tasks_completed() {
1.522 + uint* n_completed_ptr = &_n_completed;
1.523 + uint complete = *n_completed_ptr;
1.524 + while (true) {
1.525 + uint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete);
1.526 + if (res == complete) {
1.527 + break;
1.528 + }
1.529 + complete = res;
1.530 + }
1.531 + if (complete+1 == _n_threads) {
1.532 + clear();
1.533 + return true;
1.534 + }
1.535 + return false;
1.536 +}
1.537 +
1.538 +bool FreeIdSet::_stat_init = false;
1.539 +FreeIdSet* FreeIdSet::_sets[NSets];
1.540 +bool FreeIdSet::_safepoint;
1.541 +
1.542 +FreeIdSet::FreeIdSet(int sz, Monitor* mon) :
1.543 + _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0)
1.544 +{
1.545 + _ids = NEW_C_HEAP_ARRAY(int, sz, mtInternal);
1.546 + for (int i = 0; i < sz; i++) _ids[i] = i+1;
1.547 + _ids[sz-1] = end_of_list; // end of list.
1.548 + if (_stat_init) {
1.549 + for (int j = 0; j < NSets; j++) _sets[j] = NULL;
1.550 + _stat_init = true;
1.551 + }
1.552 + // Add to sets. (This should happen while the system is still single-threaded.)
1.553 + for (int j = 0; j < NSets; j++) {
1.554 + if (_sets[j] == NULL) {
1.555 + _sets[j] = this;
1.556 + _index = j;
1.557 + break;
1.558 + }
1.559 + }
1.560 + guarantee(_index != -1, "Too many FreeIdSets in use!");
1.561 +}
1.562 +
1.563 +FreeIdSet::~FreeIdSet() {
1.564 + _sets[_index] = NULL;
1.565 + FREE_C_HEAP_ARRAY(int, _ids, mtInternal);
1.566 +}
1.567 +
1.568 +void FreeIdSet::set_safepoint(bool b) {
1.569 + _safepoint = b;
1.570 + if (b) {
1.571 + for (int j = 0; j < NSets; j++) {
1.572 + if (_sets[j] != NULL && _sets[j]->_waiters > 0) {
1.573 + Monitor* mon = _sets[j]->_mon;
1.574 + mon->lock_without_safepoint_check();
1.575 + mon->notify_all();
1.576 + mon->unlock();
1.577 + }
1.578 + }
1.579 + }
1.580 +}
1.581 +
1.582 +#define FID_STATS 0
1.583 +
1.584 +int FreeIdSet::claim_par_id() {
1.585 +#if FID_STATS
1.586 + thread_t tslf = thr_self();
1.587 + tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed);
1.588 +#endif
1.589 + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
1.590 + while (!_safepoint && _hd == end_of_list) {
1.591 + _waiters++;
1.592 +#if FID_STATS
1.593 + if (_waiters > 5) {
1.594 + tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n",
1.595 + tslf, _waiters, _claimed);
1.596 + }
1.597 +#endif
1.598 + _mon->wait(Mutex::_no_safepoint_check_flag);
1.599 + _waiters--;
1.600 + }
1.601 + if (_hd == end_of_list) {
1.602 +#if FID_STATS
1.603 + tty->print("claim_par_id[%d]: returning EOL.\n", tslf);
1.604 +#endif
1.605 + return -1;
1.606 + } else {
1.607 + int res = _hd;
1.608 + _hd = _ids[res];
1.609 + _ids[res] = claimed; // For debugging.
1.610 + _claimed++;
1.611 +#if FID_STATS
1.612 + tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n",
1.613 + tslf, res, _claimed);
1.614 +#endif
1.615 + return res;
1.616 + }
1.617 +}
1.618 +
1.619 +bool FreeIdSet::claim_perm_id(int i) {
1.620 + assert(0 <= i && i < _sz, "Out of range.");
1.621 + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
1.622 + int prev = end_of_list;
1.623 + int cur = _hd;
1.624 + while (cur != end_of_list) {
1.625 + if (cur == i) {
1.626 + if (prev == end_of_list) {
1.627 + _hd = _ids[cur];
1.628 + } else {
1.629 + _ids[prev] = _ids[cur];
1.630 + }
1.631 + _ids[cur] = claimed;
1.632 + _claimed++;
1.633 + return true;
1.634 + } else {
1.635 + prev = cur;
1.636 + cur = _ids[cur];
1.637 + }
1.638 + }
1.639 + return false;
1.640 +
1.641 +}
1.642 +
1.643 +void FreeIdSet::release_par_id(int id) {
1.644 + MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
1.645 + assert(_ids[id] == claimed, "Precondition.");
1.646 + _ids[id] = _hd;
1.647 + _hd = id;
1.648 + _claimed--;
1.649 +#if FID_STATS
1.650 + tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n",
1.651 + thr_self(), id, _waiters, _claimed);
1.652 +#endif
1.653 + if (_waiters > 0)
1.654 + // Notify all would be safer, but this is OK, right?
1.655 + _mon->notify_all();
1.656 +}
