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/*
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* Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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# include "incls/_precompiled.incl"
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# include "incls/_workgroup.cpp.incl"
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// Definitions of WorkGang methods.
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AbstractWorkGang::AbstractWorkGang(const char* name,
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bool are_GC_task_threads,
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bool are_ConcurrentGC_threads) :
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_name(name),
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_are_GC_task_threads(are_GC_task_threads),
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_are_ConcurrentGC_threads(are_ConcurrentGC_threads) {
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assert(!(are_GC_task_threads && are_ConcurrentGC_threads),
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"They cannot both be STW GC and Concurrent threads" );
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// Other initialization.
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_monitor = new Monitor(/* priority */ Mutex::leaf,
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/* name */ "WorkGroup monitor",
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/* allow_vm_block */ are_GC_task_threads);
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assert(monitor() != NULL, "Failed to allocate monitor");
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_terminate = false;
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_task = NULL;
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_sequence_number = 0;
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_started_workers = 0;
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_finished_workers = 0;
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}
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WorkGang::WorkGang(const char* name,
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int workers,
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bool are_GC_task_threads,
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bool are_ConcurrentGC_threads) :
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AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads)
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{
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// Save arguments.
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_total_workers = workers;
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if (TraceWorkGang) {
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tty->print_cr("Constructing work gang %s with %d threads", name, workers);
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}
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_gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, workers);
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if (gang_workers() == NULL) {
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vm_exit_out_of_memory(0, "Cannot create GangWorker array.");
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}
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for (int worker = 0; worker < total_workers(); worker += 1) {
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GangWorker* new_worker = new GangWorker(this, worker);
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assert(new_worker != NULL, "Failed to allocate GangWorker");
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_gang_workers[worker] = new_worker;
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if (new_worker == NULL || !os::create_thread(new_worker, os::pgc_thread))
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vm_exit_out_of_memory(0, "Cannot create worker GC thread. Out of system resources.");
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if (!DisableStartThread) {
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os::start_thread(new_worker);
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}
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}
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}
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AbstractWorkGang::~AbstractWorkGang() {
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if (TraceWorkGang) {
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tty->print_cr("Destructing work gang %s", name());
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}
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stop(); // stop all the workers
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for (int worker = 0; worker < total_workers(); worker += 1) {
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delete gang_worker(worker);
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}
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delete gang_workers();
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delete monitor();
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}
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GangWorker* AbstractWorkGang::gang_worker(int i) const {
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// Array index bounds checking.
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GangWorker* result = NULL;
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assert(gang_workers() != NULL, "No workers for indexing");
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assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds");
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result = _gang_workers[i];
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assert(result != NULL, "Indexing to null worker");
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return result;
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}
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void WorkGang::run_task(AbstractGangTask* task) {
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// This thread is executed by the VM thread which does not block
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// on ordinary MutexLocker's.
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MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
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if (TraceWorkGang) {
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tty->print_cr("Running work gang %s task %s", name(), task->name());
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}
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// Tell all the workers to run a task.
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assert(task != NULL, "Running a null task");
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// Initialize.
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_task = task;
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_sequence_number += 1;
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_started_workers = 0;
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_finished_workers = 0;
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// Tell the workers to get to work.
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monitor()->notify_all();
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// Wait for them to be finished
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while (finished_workers() < total_workers()) {
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if (TraceWorkGang) {
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tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d",
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name(), finished_workers(), total_workers(),
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_sequence_number);
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}
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monitor()->wait(/* no_safepoint_check */ true);
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}
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_task = NULL;
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if (TraceWorkGang) {
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tty->print_cr("/nFinished work gang %s: %d/%d sequence %d",
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name(), finished_workers(), total_workers(),
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_sequence_number);
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}
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}
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void AbstractWorkGang::stop() {
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// Tell all workers to terminate, then wait for them to become inactive.
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MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag);
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if (TraceWorkGang) {
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tty->print_cr("Stopping work gang %s task %s", name(), task()->name());
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}
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_task = NULL;
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_terminate = true;
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monitor()->notify_all();
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while (finished_workers() < total_workers()) {
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if (TraceWorkGang) {
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tty->print_cr("Waiting in work gang %s: %d/%d finished",
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name(), finished_workers(), total_workers());
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}
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monitor()->wait(/* no_safepoint_check */ true);
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}
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}
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void AbstractWorkGang::internal_worker_poll(WorkData* data) const {
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assert(monitor()->owned_by_self(), "worker_poll is an internal method");
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assert(data != NULL, "worker data is null");
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data->set_terminate(terminate());
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data->set_task(task());
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data->set_sequence_number(sequence_number());
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}
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void AbstractWorkGang::internal_note_start() {
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assert(monitor()->owned_by_self(), "note_finish is an internal method");
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_started_workers += 1;
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}
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void AbstractWorkGang::internal_note_finish() {
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assert(monitor()->owned_by_self(), "note_finish is an internal method");
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_finished_workers += 1;
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}
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void AbstractWorkGang::print_worker_threads_on(outputStream* st) const {
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uint num_thr = total_workers();
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for (uint i = 0; i < num_thr; i++) {
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gang_worker(i)->print_on(st);
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st->cr();
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}
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}
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void AbstractWorkGang::threads_do(ThreadClosure* tc) const {
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assert(tc != NULL, "Null ThreadClosure");
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uint num_thr = total_workers();
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for (uint i = 0; i < num_thr; i++) {
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tc->do_thread(gang_worker(i));
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}
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}
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// GangWorker methods.
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GangWorker::GangWorker(AbstractWorkGang* gang, uint id) {
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_gang = gang;
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set_id(id);
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set_name("Gang worker#%d (%s)", id, gang->name());
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}
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void GangWorker::run() {
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initialize();
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loop();
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}
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void GangWorker::initialize() {
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this->initialize_thread_local_storage();
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assert(_gang != NULL, "No gang to run in");
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os::set_priority(this, NearMaxPriority);
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if (TraceWorkGang) {
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tty->print_cr("Running gang worker for gang %s id %d",
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gang()->name(), id());
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}
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// The VM thread should not execute here because MutexLocker's are used
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// as (opposed to MutexLockerEx's).
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assert(!Thread::current()->is_VM_thread(), "VM thread should not be part"
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" of a work gang");
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}
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void GangWorker::loop() {
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int previous_sequence_number = 0;
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Monitor* gang_monitor = gang()->monitor();
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for ( ; /* !terminate() */; ) {
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WorkData data;
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int part; // Initialized below.
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{
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// Grab the gang mutex.
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MutexLocker ml(gang_monitor);
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// Wait for something to do.
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// Polling outside the while { wait } avoids missed notifies
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// in the outer loop.
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gang()->internal_worker_poll(&data);
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if (TraceWorkGang) {
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tty->print("Polled outside for work in gang %s worker %d",
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gang()->name(), id());
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tty->print(" terminate: %s",
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data.terminate() ? "true" : "false");
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tty->print(" sequence: %d (prev: %d)",
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data.sequence_number(), previous_sequence_number);
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if (data.task() != NULL) {
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tty->print(" task: %s", data.task()->name());
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} else {
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tty->print(" task: NULL");
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}
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tty->cr();
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}
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for ( ; /* break or return */; ) {
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// Terminate if requested.
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if (data.terminate()) {
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gang()->internal_note_finish();
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gang_monitor->notify_all();
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return;
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}
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// Check for new work.
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if ((data.task() != NULL) &&
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(data.sequence_number() != previous_sequence_number)) {
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gang()->internal_note_start();
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gang_monitor->notify_all();
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part = gang()->started_workers() - 1;
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break;
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}
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// Nothing to do.
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gang_monitor->wait(/* no_safepoint_check */ true);
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gang()->internal_worker_poll(&data);
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if (TraceWorkGang) {
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tty->print("Polled inside for work in gang %s worker %d",
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gang()->name(), id());
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tty->print(" terminate: %s",
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data.terminate() ? "true" : "false");
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tty->print(" sequence: %d (prev: %d)",
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data.sequence_number(), previous_sequence_number);
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if (data.task() != NULL) {
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tty->print(" task: %s", data.task()->name());
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} else {
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tty->print(" task: NULL");
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}
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tty->cr();
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}
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}
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// Drop gang mutex.
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}
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if (TraceWorkGang) {
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tty->print("Work for work gang %s id %d task %s part %d",
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gang()->name(), id(), data.task()->name(), part);
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}
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assert(data.task() != NULL, "Got null task");
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data.task()->work(part);
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{
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if (TraceWorkGang) {
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tty->print("Finish for work gang %s id %d task %s part %d",
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gang()->name(), id(), data.task()->name(), part);
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}
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// Grab the gang mutex.
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MutexLocker ml(gang_monitor);
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gang()->internal_note_finish();
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// Tell the gang you are done.
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gang_monitor->notify_all();
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// Drop the gang mutex.
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}
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previous_sequence_number = data.sequence_number();
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}
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}
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bool GangWorker::is_GC_task_thread() const {
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return gang()->are_GC_task_threads();
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}
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bool GangWorker::is_ConcurrentGC_thread() const {
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return gang()->are_ConcurrentGC_threads();
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}
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void GangWorker::print_on(outputStream* st) const {
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st->print("\"%s\" ", name());
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Thread::print_on(st);
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st->cr();
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}
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// Printing methods
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const char* AbstractWorkGang::name() const {
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return _name;
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}
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#ifndef PRODUCT
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const char* AbstractGangTask::name() const {
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return _name;
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}
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#endif /* PRODUCT */
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// *** WorkGangBarrierSync
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WorkGangBarrierSync::WorkGangBarrierSync()
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: _monitor(Mutex::safepoint, "work gang barrier sync", true),
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_n_workers(0), _n_completed(0), _should_reset(false) {
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}
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WorkGangBarrierSync::WorkGangBarrierSync(int n_workers, const char* name)
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: _monitor(Mutex::safepoint, name, true),
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_n_workers(n_workers), _n_completed(0), _should_reset(false) {
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}
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void WorkGangBarrierSync::set_n_workers(int n_workers) {
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_n_workers = n_workers;
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_n_completed = 0;
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_should_reset = false;
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1
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}
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void WorkGangBarrierSync::enter() {
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MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
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if (should_reset()) {
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// The should_reset() was set and we are the first worker to enter
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// the sync barrier. We will zero the n_completed() count which
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// effectively resets the barrier.
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zero_completed();
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set_should_reset(false);
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}
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inc_completed();
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if (n_completed() == n_workers()) {
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// At this point we would like to reset the barrier to be ready in
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// case it is used again. However, we cannot set n_completed() to
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// 0, even after the notify_all(), given that some other workers
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// might still be waiting for n_completed() to become ==
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// n_workers(). So, if we set n_completed() to 0, those workers
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// will get stuck (as they will wake up, see that n_completed() !=
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// n_workers() and go back to sleep). Instead, we raise the
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// should_reset() flag and the barrier will be reset the first
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// time a worker enters it again.
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set_should_reset(true);
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monitor()->notify_all();
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} else {
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while (n_completed() != n_workers()) {
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monitor()->wait(/* no_safepoint_check */ true);
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}
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}
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}
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// SubTasksDone functions.
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SubTasksDone::SubTasksDone(int n) :
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_n_tasks(n), _n_threads(1), _tasks(NULL) {
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_tasks = NEW_C_HEAP_ARRAY(jint, n);
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guarantee(_tasks != NULL, "alloc failure");
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clear();
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}
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bool SubTasksDone::valid() {
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return _tasks != NULL;
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}
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void SubTasksDone::set_par_threads(int t) {
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#ifdef ASSERT
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assert(_claimed == 0 || _threads_completed == _n_threads,
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"should not be called while tasks are being processed!");
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#endif
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_n_threads = (t == 0 ? 1 : t);
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}
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void SubTasksDone::clear() {
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for (int i = 0; i < _n_tasks; i++) {
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_tasks[i] = 0;
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}
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_threads_completed = 0;
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#ifdef ASSERT
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_claimed = 0;
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#endif
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}
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|
404 |
bool SubTasksDone::is_task_claimed(int t) {
|
|
405 |
assert(0 <= t && t < _n_tasks, "bad task id.");
|
|
406 |
jint old = _tasks[t];
|
|
407 |
if (old == 0) {
|
|
408 |
old = Atomic::cmpxchg(1, &_tasks[t], 0);
|
|
409 |
}
|
|
410 |
assert(_tasks[t] == 1, "What else?");
|
|
411 |
bool res = old != 0;
|
|
412 |
#ifdef ASSERT
|
|
413 |
if (!res) {
|
|
414 |
assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?");
|
|
415 |
Atomic::inc(&_claimed);
|
|
416 |
}
|
|
417 |
#endif
|
|
418 |
return res;
|
|
419 |
}
|
|
420 |
|
|
421 |
void SubTasksDone::all_tasks_completed() {
|
|
422 |
jint observed = _threads_completed;
|
|
423 |
jint old;
|
|
424 |
do {
|
|
425 |
old = observed;
|
|
426 |
observed = Atomic::cmpxchg(old+1, &_threads_completed, old);
|
|
427 |
} while (observed != old);
|
|
428 |
// If this was the last thread checking in, clear the tasks.
|
|
429 |
if (observed+1 == _n_threads) clear();
|
|
430 |
}
|
|
431 |
|
|
432 |
|
|
433 |
SubTasksDone::~SubTasksDone() {
|
|
434 |
if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks);
|
|
435 |
}
|
|
436 |
|
|
437 |
// *** SequentialSubTasksDone
|
|
438 |
|
|
439 |
void SequentialSubTasksDone::clear() {
|
|
440 |
_n_tasks = _n_claimed = 0;
|
|
441 |
_n_threads = _n_completed = 0;
|
|
442 |
}
|
|
443 |
|
|
444 |
bool SequentialSubTasksDone::valid() {
|
|
445 |
return _n_threads > 0;
|
|
446 |
}
|
|
447 |
|
|
448 |
bool SequentialSubTasksDone::is_task_claimed(int& t) {
|
|
449 |
jint* n_claimed_ptr = &_n_claimed;
|
|
450 |
t = *n_claimed_ptr;
|
|
451 |
while (t < _n_tasks) {
|
|
452 |
jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t);
|
|
453 |
if (res == t) {
|
|
454 |
return false;
|
|
455 |
}
|
|
456 |
t = *n_claimed_ptr;
|
|
457 |
}
|
|
458 |
return true;
|
|
459 |
}
|
|
460 |
|
|
461 |
bool SequentialSubTasksDone::all_tasks_completed() {
|
|
462 |
jint* n_completed_ptr = &_n_completed;
|
|
463 |
jint complete = *n_completed_ptr;
|
|
464 |
while (true) {
|
|
465 |
jint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete);
|
|
466 |
if (res == complete) {
|
|
467 |
break;
|
|
468 |
}
|
|
469 |
complete = res;
|
|
470 |
}
|
|
471 |
if (complete+1 == _n_threads) {
|
|
472 |
clear();
|
|
473 |
return true;
|
|
474 |
}
|
|
475 |
return false;
|
|
476 |
}
|
1374
|
477 |
|
|
478 |
bool FreeIdSet::_stat_init = false;
|
|
479 |
FreeIdSet* FreeIdSet::_sets[NSets];
|
|
480 |
bool FreeIdSet::_safepoint;
|
|
481 |
|
|
482 |
FreeIdSet::FreeIdSet(int sz, Monitor* mon) :
|
|
483 |
_sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0)
|
|
484 |
{
|
|
485 |
_ids = new int[sz];
|
|
486 |
for (int i = 0; i < sz; i++) _ids[i] = i+1;
|
|
487 |
_ids[sz-1] = end_of_list; // end of list.
|
|
488 |
if (_stat_init) {
|
|
489 |
for (int j = 0; j < NSets; j++) _sets[j] = NULL;
|
|
490 |
_stat_init = true;
|
|
491 |
}
|
|
492 |
// Add to sets. (This should happen while the system is still single-threaded.)
|
|
493 |
for (int j = 0; j < NSets; j++) {
|
|
494 |
if (_sets[j] == NULL) {
|
|
495 |
_sets[j] = this;
|
|
496 |
_index = j;
|
|
497 |
break;
|
|
498 |
}
|
|
499 |
}
|
|
500 |
guarantee(_index != -1, "Too many FreeIdSets in use!");
|
|
501 |
}
|
|
502 |
|
|
503 |
FreeIdSet::~FreeIdSet() {
|
|
504 |
_sets[_index] = NULL;
|
|
505 |
}
|
|
506 |
|
|
507 |
void FreeIdSet::set_safepoint(bool b) {
|
|
508 |
_safepoint = b;
|
|
509 |
if (b) {
|
|
510 |
for (int j = 0; j < NSets; j++) {
|
|
511 |
if (_sets[j] != NULL && _sets[j]->_waiters > 0) {
|
|
512 |
Monitor* mon = _sets[j]->_mon;
|
|
513 |
mon->lock_without_safepoint_check();
|
|
514 |
mon->notify_all();
|
|
515 |
mon->unlock();
|
|
516 |
}
|
|
517 |
}
|
|
518 |
}
|
|
519 |
}
|
|
520 |
|
|
521 |
#define FID_STATS 0
|
|
522 |
|
|
523 |
int FreeIdSet::claim_par_id() {
|
|
524 |
#if FID_STATS
|
|
525 |
thread_t tslf = thr_self();
|
|
526 |
tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed);
|
|
527 |
#endif
|
|
528 |
MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
|
|
529 |
while (!_safepoint && _hd == end_of_list) {
|
|
530 |
_waiters++;
|
|
531 |
#if FID_STATS
|
|
532 |
if (_waiters > 5) {
|
|
533 |
tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n",
|
|
534 |
tslf, _waiters, _claimed);
|
|
535 |
}
|
|
536 |
#endif
|
|
537 |
_mon->wait(Mutex::_no_safepoint_check_flag);
|
|
538 |
_waiters--;
|
|
539 |
}
|
|
540 |
if (_hd == end_of_list) {
|
|
541 |
#if FID_STATS
|
|
542 |
tty->print("claim_par_id[%d]: returning EOL.\n", tslf);
|
|
543 |
#endif
|
|
544 |
return -1;
|
|
545 |
} else {
|
|
546 |
int res = _hd;
|
|
547 |
_hd = _ids[res];
|
|
548 |
_ids[res] = claimed; // For debugging.
|
|
549 |
_claimed++;
|
|
550 |
#if FID_STATS
|
|
551 |
tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n",
|
|
552 |
tslf, res, _claimed);
|
|
553 |
#endif
|
|
554 |
return res;
|
|
555 |
}
|
|
556 |
}
|
|
557 |
|
|
558 |
bool FreeIdSet::claim_perm_id(int i) {
|
|
559 |
assert(0 <= i && i < _sz, "Out of range.");
|
|
560 |
MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
|
|
561 |
int prev = end_of_list;
|
|
562 |
int cur = _hd;
|
|
563 |
while (cur != end_of_list) {
|
|
564 |
if (cur == i) {
|
|
565 |
if (prev == end_of_list) {
|
|
566 |
_hd = _ids[cur];
|
|
567 |
} else {
|
|
568 |
_ids[prev] = _ids[cur];
|
|
569 |
}
|
|
570 |
_ids[cur] = claimed;
|
|
571 |
_claimed++;
|
|
572 |
return true;
|
|
573 |
} else {
|
|
574 |
prev = cur;
|
|
575 |
cur = _ids[cur];
|
|
576 |
}
|
|
577 |
}
|
|
578 |
return false;
|
|
579 |
|
|
580 |
}
|
|
581 |
|
|
582 |
void FreeIdSet::release_par_id(int id) {
|
|
583 |
MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag);
|
|
584 |
assert(_ids[id] == claimed, "Precondition.");
|
|
585 |
_ids[id] = _hd;
|
|
586 |
_hd = id;
|
|
587 |
_claimed--;
|
|
588 |
#if FID_STATS
|
|
589 |
tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n",
|
|
590 |
thr_self(), id, _waiters, _claimed);
|
|
591 |
#endif
|
|
592 |
if (_waiters > 0)
|
|
593 |
// Notify all would be safer, but this is OK, right?
|
|
594 |
_mon->notify_all();
|
|
595 |
}
|