| /* |
| * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "memory/allocation.hpp" |
| #include "memory/allocation.inline.hpp" |
| #include "runtime/os.hpp" |
| #include "utilities/workgroup.hpp" |
| |
| PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
| |
| // Definitions of WorkGang methods. |
| |
| AbstractWorkGang::AbstractWorkGang(const char* name, |
| bool are_GC_task_threads, |
| bool are_ConcurrentGC_threads) : |
| _name(name), |
| _are_GC_task_threads(are_GC_task_threads), |
| _are_ConcurrentGC_threads(are_ConcurrentGC_threads) { |
| |
| assert(!(are_GC_task_threads && are_ConcurrentGC_threads), |
| "They cannot both be STW GC and Concurrent threads" ); |
| |
| // Other initialization. |
| _monitor = new Monitor(/* priority */ Mutex::leaf, |
| /* name */ "WorkGroup monitor", |
| /* allow_vm_block */ are_GC_task_threads); |
| assert(monitor() != NULL, "Failed to allocate monitor"); |
| _terminate = false; |
| _task = NULL; |
| _sequence_number = 0; |
| _started_workers = 0; |
| _finished_workers = 0; |
| } |
| |
| WorkGang::WorkGang(const char* name, |
| uint workers, |
| bool are_GC_task_threads, |
| bool are_ConcurrentGC_threads) : |
| AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) { |
| _total_workers = workers; |
| } |
| |
| GangWorker* WorkGang::allocate_worker(uint which) { |
| GangWorker* new_worker = new GangWorker(this, which); |
| return new_worker; |
| } |
| |
| // The current implementation will exit if the allocation |
| // of any worker fails. Still, return a boolean so that |
| // a future implementation can possibly do a partial |
| // initialization of the workers and report such to the |
| // caller. |
| bool WorkGang::initialize_workers() { |
| |
| if (TraceWorkGang) { |
| tty->print_cr("Constructing work gang %s with %d threads", |
| name(), |
| total_workers()); |
| } |
| _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, total_workers(), mtInternal); |
| if (gang_workers() == NULL) { |
| vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GangWorker array."); |
| return false; |
| } |
| os::ThreadType worker_type; |
| if (are_ConcurrentGC_threads()) { |
| worker_type = os::cgc_thread; |
| } else { |
| worker_type = os::pgc_thread; |
| } |
| for (uint worker = 0; worker < total_workers(); worker += 1) { |
| GangWorker* new_worker = allocate_worker(worker); |
| assert(new_worker != NULL, "Failed to allocate GangWorker"); |
| _gang_workers[worker] = new_worker; |
| if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) { |
| vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, |
| "Cannot create worker GC thread. Out of system resources."); |
| return false; |
| } |
| if (!DisableStartThread) { |
| os::start_thread(new_worker); |
| } |
| } |
| return true; |
| } |
| |
| AbstractWorkGang::~AbstractWorkGang() { |
| if (TraceWorkGang) { |
| tty->print_cr("Destructing work gang %s", name()); |
| } |
| stop(); // stop all the workers |
| for (uint worker = 0; worker < total_workers(); worker += 1) { |
| delete gang_worker(worker); |
| } |
| delete gang_workers(); |
| delete monitor(); |
| } |
| |
| GangWorker* AbstractWorkGang::gang_worker(uint i) const { |
| // Array index bounds checking. |
| GangWorker* result = NULL; |
| assert(gang_workers() != NULL, "No workers for indexing"); |
| assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds"); |
| result = _gang_workers[i]; |
| assert(result != NULL, "Indexing to null worker"); |
| return result; |
| } |
| |
| void WorkGang::run_task(AbstractGangTask* task) { |
| run_task(task, total_workers()); |
| } |
| |
| void WorkGang::run_task(AbstractGangTask* task, uint no_of_parallel_workers) { |
| task->set_for_termination(no_of_parallel_workers); |
| |
| // This thread is executed by the VM thread which does not block |
| // on ordinary MutexLocker's. |
| MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); |
| if (TraceWorkGang) { |
| tty->print_cr("Running work gang %s task %s", name(), task->name()); |
| } |
| // Tell all the workers to run a task. |
| assert(task != NULL, "Running a null task"); |
| // Initialize. |
| _task = task; |
| _sequence_number += 1; |
| _started_workers = 0; |
| _finished_workers = 0; |
| // Tell the workers to get to work. |
| monitor()->notify_all(); |
| // Wait for them to be finished |
| while (finished_workers() < no_of_parallel_workers) { |
| if (TraceWorkGang) { |
| tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d", |
| name(), finished_workers(), no_of_parallel_workers, |
| _sequence_number); |
| } |
| monitor()->wait(/* no_safepoint_check */ true); |
| } |
| _task = NULL; |
| if (TraceWorkGang) { |
| tty->print_cr("\nFinished work gang %s: %d/%d sequence %d", |
| name(), finished_workers(), no_of_parallel_workers, |
| _sequence_number); |
| Thread* me = Thread::current(); |
| tty->print_cr(" T: 0x%x VM_thread: %d", me, me->is_VM_thread()); |
| } |
| } |
| |
| void FlexibleWorkGang::run_task(AbstractGangTask* task) { |
| // If active_workers() is passed, _finished_workers |
| // must only be incremented for workers that find non_null |
| // work (as opposed to all those that just check that the |
| // task is not null). |
| WorkGang::run_task(task, (uint) active_workers()); |
| } |
| |
| void AbstractWorkGang::stop() { |
| // Tell all workers to terminate, then wait for them to become inactive. |
| MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); |
| if (TraceWorkGang) { |
| tty->print_cr("Stopping work gang %s task %s", name(), task()->name()); |
| } |
| _task = NULL; |
| _terminate = true; |
| monitor()->notify_all(); |
| while (finished_workers() < active_workers()) { |
| if (TraceWorkGang) { |
| tty->print_cr("Waiting in work gang %s: %d/%d finished", |
| name(), finished_workers(), active_workers()); |
| } |
| monitor()->wait(/* no_safepoint_check */ true); |
| } |
| } |
| |
| void AbstractWorkGang::internal_worker_poll(WorkData* data) const { |
| assert(monitor()->owned_by_self(), "worker_poll is an internal method"); |
| assert(data != NULL, "worker data is null"); |
| data->set_terminate(terminate()); |
| data->set_task(task()); |
| data->set_sequence_number(sequence_number()); |
| } |
| |
| void AbstractWorkGang::internal_note_start() { |
| assert(monitor()->owned_by_self(), "note_finish is an internal method"); |
| _started_workers += 1; |
| } |
| |
| void AbstractWorkGang::internal_note_finish() { |
| assert(monitor()->owned_by_self(), "note_finish is an internal method"); |
| _finished_workers += 1; |
| } |
| |
| void AbstractWorkGang::print_worker_threads_on(outputStream* st) const { |
| uint num_thr = total_workers(); |
| for (uint i = 0; i < num_thr; i++) { |
| gang_worker(i)->print_on(st); |
| st->cr(); |
| } |
| } |
| |
| void AbstractWorkGang::threads_do(ThreadClosure* tc) const { |
| assert(tc != NULL, "Null ThreadClosure"); |
| uint num_thr = total_workers(); |
| for (uint i = 0; i < num_thr; i++) { |
| tc->do_thread(gang_worker(i)); |
| } |
| } |
| |
| // GangWorker methods. |
| |
| GangWorker::GangWorker(AbstractWorkGang* gang, uint id) { |
| _gang = gang; |
| set_id(id); |
| set_name("Gang worker#%d (%s)", id, gang->name()); |
| } |
| |
| void GangWorker::run() { |
| initialize(); |
| loop(); |
| } |
| |
| void GangWorker::initialize() { |
| this->initialize_thread_local_storage(); |
| this->record_stack_base_and_size(); |
| assert(_gang != NULL, "No gang to run in"); |
| os::set_priority(this, NearMaxPriority); |
| if (TraceWorkGang) { |
| tty->print_cr("Running gang worker for gang %s id %d", |
| gang()->name(), id()); |
| } |
| // The VM thread should not execute here because MutexLocker's are used |
| // as (opposed to MutexLockerEx's). |
| assert(!Thread::current()->is_VM_thread(), "VM thread should not be part" |
| " of a work gang"); |
| } |
| |
| void GangWorker::loop() { |
| int previous_sequence_number = 0; |
| Monitor* gang_monitor = gang()->monitor(); |
| for ( ; /* !terminate() */; ) { |
| WorkData data; |
| int part; // Initialized below. |
| { |
| // Grab the gang mutex. |
| MutexLocker ml(gang_monitor); |
| // Wait for something to do. |
| // Polling outside the while { wait } avoids missed notifies |
| // in the outer loop. |
| gang()->internal_worker_poll(&data); |
| if (TraceWorkGang) { |
| tty->print("Polled outside for work in gang %s worker %d", |
| gang()->name(), id()); |
| tty->print(" terminate: %s", |
| data.terminate() ? "true" : "false"); |
| tty->print(" sequence: %d (prev: %d)", |
| data.sequence_number(), previous_sequence_number); |
| if (data.task() != NULL) { |
| tty->print(" task: %s", data.task()->name()); |
| } else { |
| tty->print(" task: NULL"); |
| } |
| tty->cr(); |
| } |
| for ( ; /* break or return */; ) { |
| // Terminate if requested. |
| if (data.terminate()) { |
| gang()->internal_note_finish(); |
| gang_monitor->notify_all(); |
| return; |
| } |
| // Check for new work. |
| if ((data.task() != NULL) && |
| (data.sequence_number() != previous_sequence_number)) { |
| if (gang()->needs_more_workers()) { |
| gang()->internal_note_start(); |
| gang_monitor->notify_all(); |
| part = gang()->started_workers() - 1; |
| break; |
| } |
| } |
| // Nothing to do. |
| gang_monitor->wait(/* no_safepoint_check */ true); |
| gang()->internal_worker_poll(&data); |
| if (TraceWorkGang) { |
| tty->print("Polled inside for work in gang %s worker %d", |
| gang()->name(), id()); |
| tty->print(" terminate: %s", |
| data.terminate() ? "true" : "false"); |
| tty->print(" sequence: %d (prev: %d)", |
| data.sequence_number(), previous_sequence_number); |
| if (data.task() != NULL) { |
| tty->print(" task: %s", data.task()->name()); |
| } else { |
| tty->print(" task: NULL"); |
| } |
| tty->cr(); |
| } |
| } |
| // Drop gang mutex. |
| } |
| if (TraceWorkGang) { |
| tty->print("Work for work gang %s id %d task %s part %d", |
| gang()->name(), id(), data.task()->name(), part); |
| } |
| assert(data.task() != NULL, "Got null task"); |
| data.task()->work(part); |
| { |
| if (TraceWorkGang) { |
| tty->print("Finish for work gang %s id %d task %s part %d", |
| gang()->name(), id(), data.task()->name(), part); |
| } |
| // Grab the gang mutex. |
| MutexLocker ml(gang_monitor); |
| gang()->internal_note_finish(); |
| // Tell the gang you are done. |
| gang_monitor->notify_all(); |
| // Drop the gang mutex. |
| } |
| previous_sequence_number = data.sequence_number(); |
| } |
| } |
| |
| bool GangWorker::is_GC_task_thread() const { |
| return gang()->are_GC_task_threads(); |
| } |
| |
| bool GangWorker::is_ConcurrentGC_thread() const { |
| return gang()->are_ConcurrentGC_threads(); |
| } |
| |
| void GangWorker::print_on(outputStream* st) const { |
| st->print("\"%s\" ", name()); |
| Thread::print_on(st); |
| st->cr(); |
| } |
| |
| // Printing methods |
| |
| const char* AbstractWorkGang::name() const { |
| return _name; |
| } |
| |
| #ifndef PRODUCT |
| |
| const char* AbstractGangTask::name() const { |
| return _name; |
| } |
| |
| #endif /* PRODUCT */ |
| |
| // FlexibleWorkGang |
| |
| |
| // *** WorkGangBarrierSync |
| |
| WorkGangBarrierSync::WorkGangBarrierSync() |
| : _monitor(Mutex::safepoint, "work gang barrier sync", true), |
| _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) { |
| } |
| |
| WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name) |
| : _monitor(Mutex::safepoint, name, true), |
| _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) { |
| } |
| |
| void WorkGangBarrierSync::set_n_workers(uint n_workers) { |
| _n_workers = n_workers; |
| _n_completed = 0; |
| _should_reset = false; |
| _aborted = false; |
| } |
| |
| bool WorkGangBarrierSync::enter() { |
| MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
| if (should_reset()) { |
| // The should_reset() was set and we are the first worker to enter |
| // the sync barrier. We will zero the n_completed() count which |
| // effectively resets the barrier. |
| zero_completed(); |
| set_should_reset(false); |
| } |
| inc_completed(); |
| if (n_completed() == n_workers()) { |
| // At this point we would like to reset the barrier to be ready in |
| // case it is used again. However, we cannot set n_completed() to |
| // 0, even after the notify_all(), given that some other workers |
| // might still be waiting for n_completed() to become == |
| // n_workers(). So, if we set n_completed() to 0, those workers |
| // will get stuck (as they will wake up, see that n_completed() != |
| // n_workers() and go back to sleep). Instead, we raise the |
| // should_reset() flag and the barrier will be reset the first |
| // time a worker enters it again. |
| set_should_reset(true); |
| monitor()->notify_all(); |
| } else { |
| while (n_completed() != n_workers() && !aborted()) { |
| monitor()->wait(/* no_safepoint_check */ true); |
| } |
| } |
| return !aborted(); |
| } |
| |
| void WorkGangBarrierSync::abort() { |
| MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
| set_aborted(); |
| monitor()->notify_all(); |
| } |
| |
| // SubTasksDone functions. |
| |
| SubTasksDone::SubTasksDone(uint n) : |
| _n_tasks(n), _n_threads(1), _tasks(NULL) { |
| _tasks = NEW_C_HEAP_ARRAY(uint, n, mtInternal); |
| guarantee(_tasks != NULL, "alloc failure"); |
| clear(); |
| } |
| |
| bool SubTasksDone::valid() { |
| return _tasks != NULL; |
| } |
| |
| void SubTasksDone::set_n_threads(uint t) { |
| assert(_claimed == 0 || _threads_completed == _n_threads, |
| "should not be called while tasks are being processed!"); |
| _n_threads = (t == 0 ? 1 : t); |
| } |
| |
| void SubTasksDone::clear() { |
| for (uint i = 0; i < _n_tasks; i++) { |
| _tasks[i] = 0; |
| } |
| _threads_completed = 0; |
| #ifdef ASSERT |
| _claimed = 0; |
| #endif |
| } |
| |
| bool SubTasksDone::is_task_claimed(uint t) { |
| assert(0 <= t && t < _n_tasks, "bad task id."); |
| uint old = _tasks[t]; |
| if (old == 0) { |
| old = Atomic::cmpxchg(1, &_tasks[t], 0); |
| } |
| assert(_tasks[t] == 1, "What else?"); |
| bool res = old != 0; |
| #ifdef ASSERT |
| if (!res) { |
| assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?"); |
| Atomic::inc((volatile jint*) &_claimed); |
| } |
| #endif |
| return res; |
| } |
| |
| void SubTasksDone::all_tasks_completed() { |
| jint observed = _threads_completed; |
| jint old; |
| do { |
| old = observed; |
| observed = Atomic::cmpxchg(old+1, &_threads_completed, old); |
| } while (observed != old); |
| // If this was the last thread checking in, clear the tasks. |
| if (observed+1 == (jint)_n_threads) clear(); |
| } |
| |
| |
| SubTasksDone::~SubTasksDone() { |
| if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks, mtInternal); |
| } |
| |
| // *** SequentialSubTasksDone |
| |
| void SequentialSubTasksDone::clear() { |
| _n_tasks = _n_claimed = 0; |
| _n_threads = _n_completed = 0; |
| } |
| |
| bool SequentialSubTasksDone::valid() { |
| return _n_threads > 0; |
| } |
| |
| bool SequentialSubTasksDone::is_task_claimed(uint& t) { |
| uint* n_claimed_ptr = &_n_claimed; |
| t = *n_claimed_ptr; |
| while (t < _n_tasks) { |
| jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t); |
| if (res == (jint)t) { |
| return false; |
| } |
| t = *n_claimed_ptr; |
| } |
| return true; |
| } |
| |
| bool SequentialSubTasksDone::all_tasks_completed() { |
| uint* n_completed_ptr = &_n_completed; |
| uint complete = *n_completed_ptr; |
| while (true) { |
| uint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete); |
| if (res == complete) { |
| break; |
| } |
| complete = res; |
| } |
| if (complete+1 == _n_threads) { |
| clear(); |
| return true; |
| } |
| return false; |
| } |
| |
| bool FreeIdSet::_stat_init = false; |
| FreeIdSet* FreeIdSet::_sets[NSets]; |
| bool FreeIdSet::_safepoint; |
| |
| FreeIdSet::FreeIdSet(int sz, Monitor* mon) : |
| _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0) |
| { |
| _ids = NEW_C_HEAP_ARRAY(int, sz, mtInternal); |
| for (int i = 0; i < sz; i++) _ids[i] = i+1; |
| _ids[sz-1] = end_of_list; // end of list. |
| if (_stat_init) { |
| for (int j = 0; j < NSets; j++) _sets[j] = NULL; |
| _stat_init = true; |
| } |
| // Add to sets. (This should happen while the system is still single-threaded.) |
| for (int j = 0; j < NSets; j++) { |
| if (_sets[j] == NULL) { |
| _sets[j] = this; |
| _index = j; |
| break; |
| } |
| } |
| guarantee(_index != -1, "Too many FreeIdSets in use!"); |
| } |
| |
| FreeIdSet::~FreeIdSet() { |
| _sets[_index] = NULL; |
| FREE_C_HEAP_ARRAY(int, _ids, mtInternal); |
| } |
| |
| void FreeIdSet::set_safepoint(bool b) { |
| _safepoint = b; |
| if (b) { |
| for (int j = 0; j < NSets; j++) { |
| if (_sets[j] != NULL && _sets[j]->_waiters > 0) { |
| Monitor* mon = _sets[j]->_mon; |
| mon->lock_without_safepoint_check(); |
| mon->notify_all(); |
| mon->unlock(); |
| } |
| } |
| } |
| } |
| |
| #define FID_STATS 0 |
| |
| int FreeIdSet::claim_par_id() { |
| #if FID_STATS |
| thread_t tslf = thr_self(); |
| tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed); |
| #endif |
| MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
| while (!_safepoint && _hd == end_of_list) { |
| _waiters++; |
| #if FID_STATS |
| if (_waiters > 5) { |
| tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n", |
| tslf, _waiters, _claimed); |
| } |
| #endif |
| _mon->wait(Mutex::_no_safepoint_check_flag); |
| _waiters--; |
| } |
| if (_hd == end_of_list) { |
| #if FID_STATS |
| tty->print("claim_par_id[%d]: returning EOL.\n", tslf); |
| #endif |
| return -1; |
| } else { |
| int res = _hd; |
| _hd = _ids[res]; |
| _ids[res] = claimed; // For debugging. |
| _claimed++; |
| #if FID_STATS |
| tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n", |
| tslf, res, _claimed); |
| #endif |
| return res; |
| } |
| } |
| |
| bool FreeIdSet::claim_perm_id(int i) { |
| assert(0 <= i && i < _sz, "Out of range."); |
| MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
| int prev = end_of_list; |
| int cur = _hd; |
| while (cur != end_of_list) { |
| if (cur == i) { |
| if (prev == end_of_list) { |
| _hd = _ids[cur]; |
| } else { |
| _ids[prev] = _ids[cur]; |
| } |
| _ids[cur] = claimed; |
| _claimed++; |
| return true; |
| } else { |
| prev = cur; |
| cur = _ids[cur]; |
| } |
| } |
| return false; |
| |
| } |
| |
| void FreeIdSet::release_par_id(int id) { |
| MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); |
| assert(_ids[id] == claimed, "Precondition."); |
| _ids[id] = _hd; |
| _hd = id; |
| _claimed--; |
| #if FID_STATS |
| tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n", |
| thr_self(), id, _waiters, _claimed); |
| #endif |
| if (_waiters > 0) |
| // Notify all would be safer, but this is OK, right? |
| _mon->notify_all(); |
| } |