1 /* 2 * Copyright (c) 2016 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 */ 24 25 #ifndef SHARE_VM_GC_SHARED_WORKERMANAGER_HPP 26 #define SHARE_VM_GC_SHARED_WORKERMANAGER_HPP 27 28 #include "gc/shared/adaptiveSizePolicy.hpp" 29 30 class WorkerManager : public AllStatic { 31 public: 32 // Create additional workers as needed. 33 // active_workers - number of workers being requested for an upcoming 34 // parallel task. 35 // total_workers - total number of workers. This is the maximum 36 // number possible. 37 // created_workers - number of workers already created. This maybe 38 // less than, equal to, or greater than active workers. If greater than 39 // or equal to active_workers, nothing is done. 40 // worker_type - type of thread. 41 // initializing - true if this is called to get the initial number of 42 // GC workers. 43 // If initializing is true, do a vm exit if the workers cannot be created. 44 // The initializing = true case is for JVM start up and failing to 45 // create all the worker at start should considered a problem so exit. 46 // If initializing = false, there are already some number of worker 47 // threads and a failure would not be optimal but should not be fatal. 48 template <class WorkerType> 49 static uint add_workers (WorkerType* holder, 50 uint active_workers, 51 uint total_workers, 52 uint created_workers, 53 os::ThreadType worker_type, 54 bool initializing) { 55 uint start = created_workers; 56 uint end = MIN2(active_workers, total_workers); 57 for (uint worker_id = start; worker_id < end; worker_id += 1) { 58 WorkerThread* new_worker = holder->install_worker(worker_id); 59 assert(new_worker != NULL, "Failed to allocate GangWorker"); 60 if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) { 61 if(initializing) { 62 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, 63 "Cannot create worker GC thread. Out of system resources."); 64 } 65 } 66 created_workers++; 67 os::start_thread(new_worker); 68 } 69 70 return created_workers; 71 } 72 73 // Log (at trace level) a change in the number of created workers. 74 template <class WorkerType> 75 static void log_worker_creation(WorkerType* holder, 76 uint previous_created_workers, 77 uint active_workers, 78 uint created_workers, 79 bool initializing) { 80 if (previous_created_workers < created_workers) { 81 const char* initializing_msg = initializing ? "Adding initial" : "Creating additional"; 82 log_trace(gc, task)("%s %s(s) active workers %u created workers %u", 83 initializing_msg, holder->group_name(), active_workers, created_workers); 84 } 85 } 86 }; 87 #endif // SHARE_VM_GC_SHARED_WORKERMANAGER_HPP