1 /* 2 * Copyright (c) 2017, 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 #include "precompiled.hpp" 26 #include "gc/cms/concurrentMarkSweepThread.hpp" 27 #include "gc/cms/cmsHeap.hpp" 28 #include "gc/cms/vmCMSOperations.hpp" 29 #include "gc/shared/genOopClosures.inline.hpp" 30 #include "gc/shared/strongRootsScope.hpp" 31 #include "gc/shared/workgroup.hpp" 32 #include "oops/oop.inline.hpp" 33 #include "runtime/vmThread.hpp" 34 #include "utilities/stack.inline.hpp" 35 36 CMSHeap::CMSHeap(GenCollectorPolicy *policy) : GenCollectedHeap(policy) { 37 _workers = new WorkGang("GC Thread", ParallelGCThreads, 38 /* are_GC_task_threads */true, 39 /* are_ConcurrentGC_threads */false); 40 _workers->initialize_workers(); 41 } 42 43 jint CMSHeap::initialize() { 44 jint status = GenCollectedHeap::initialize(); 45 if (status != JNI_OK) return status; 46 47 // If we are running CMS, create the collector responsible 48 // for collecting the CMS generations. 49 assert(collector_policy()->is_concurrent_mark_sweep_policy(), "must be CMS policy"); 50 create_cms_collector(); 51 52 return JNI_OK; 53 } 54 55 void CMSHeap::check_gen_kinds() { 56 assert(young_gen()->kind() == Generation::ParNew, 57 "Wrong youngest generation type"); 58 assert(old_gen()->kind() == Generation::ConcurrentMarkSweep, 59 "Wrong generation kind"); 60 } 61 62 CMSHeap* CMSHeap::heap() { 63 CollectedHeap* heap = Universe::heap(); 64 assert(heap != NULL, "Uninitialized access to CMSHeap::heap()"); 65 assert(heap->kind() == CollectedHeap::CMSHeap, "Not a CMSHeap"); 66 return (CMSHeap*) heap; 67 } 68 69 void CMSHeap::gc_threads_do(ThreadClosure* tc) const { 70 assert(workers() != NULL, "should have workers here"); 71 workers()->threads_do(tc); 72 ConcurrentMarkSweepThread::threads_do(tc); 73 } 74 75 void CMSHeap::print_gc_threads_on(outputStream* st) const { 76 assert(workers() != NULL, "should have workers here"); 77 workers()->print_worker_threads_on(st); 78 ConcurrentMarkSweepThread::print_all_on(st); 79 } 80 81 void CMSHeap::print_on_error(outputStream* st) const { 82 GenCollectedHeap::print_on_error(st); 83 st->cr(); 84 CMSCollector::print_on_error(st); 85 } 86 87 void CMSHeap::create_cms_collector() { 88 assert(old_gen()->kind() == Generation::ConcurrentMarkSweep, 89 "Unexpected generation kinds"); 90 assert(gen_policy()->is_concurrent_mark_sweep_policy(), "Unexpected policy type"); 91 CMSCollector* collector = 92 new CMSCollector((ConcurrentMarkSweepGeneration*) old_gen(), 93 rem_set(), 94 gen_policy()->as_concurrent_mark_sweep_policy()); 95 96 if (!collector->completed_initialization()) { 97 vm_shutdown_during_initialization("Could not create CMS collector"); 98 } 99 } 100 101 void CMSHeap::collect(GCCause::Cause cause) { 102 if (should_do_concurrent_full_gc(cause)) { 103 // Mostly concurrent full collection. 104 collect_mostly_concurrent(cause); 105 } else { 106 GenCollectedHeap::collect(cause); 107 } 108 } 109 110 bool CMSHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { 111 switch (cause) { 112 case GCCause::_gc_locker: return GCLockerInvokesConcurrent; 113 case GCCause::_java_lang_system_gc: 114 case GCCause::_dcmd_gc_run: return ExplicitGCInvokesConcurrent; 115 default: return false; 116 } 117 } 118 119 void CMSHeap::collect_mostly_concurrent(GCCause::Cause cause) { 120 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); 121 122 MutexLocker ml(Heap_lock); 123 // Read the GC counts while holding the Heap_lock 124 unsigned int full_gc_count_before = total_full_collections(); 125 unsigned int gc_count_before = total_collections(); 126 { 127 MutexUnlocker mu(Heap_lock); 128 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); 129 VMThread::execute(&op); 130 } 131 } 132 133 void CMSHeap::stop() { 134 ConcurrentMarkSweepThread::cmst()->stop(); 135 } 136 137 void CMSHeap::cms_process_roots(StrongRootsScope* scope, 138 bool young_gen_as_roots, 139 ScanningOption so, 140 bool only_strong_roots, 141 OopsInGenClosure* root_closure, 142 CLDClosure* cld_closure) { 143 MarkingCodeBlobClosure mark_code_closure(root_closure, !CodeBlobToOopClosure::FixRelocations); 144 OopsInGenClosure* weak_roots = only_strong_roots ? NULL : root_closure; 145 CLDClosure* weak_cld_closure = only_strong_roots ? NULL : cld_closure; 146 147 process_roots(scope, so, root_closure, weak_roots, cld_closure, weak_cld_closure, &mark_code_closure); 148 if (!only_strong_roots) { 149 process_string_table_roots(scope, root_closure); 150 } 151 152 if (young_gen_as_roots && 153 !_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { 154 root_closure->set_generation(young_gen()); 155 young_gen()->oop_iterate(root_closure); 156 root_closure->reset_generation(); 157 } 158 159 _process_strong_tasks->all_tasks_completed(scope->n_threads()); 160 } 161 162 void CMSHeap::gc_prologue(bool full) { 163 always_do_update_barrier = false; 164 GenCollectedHeap::gc_prologue(full); 165 }; 166 167 void CMSHeap::gc_epilogue(bool full) { 168 GenCollectedHeap::gc_epilogue(full); 169 always_do_update_barrier = true; 170 };