1 /* 2 * Copyright (c) 2001, 2015, 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_IMPLEMENTATION_G1_SATBQUEUE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP 27 28 #include "gc_implementation/g1/ptrQueue.hpp" 29 30 class ObjectClosure; 31 class JavaThread; 32 class SATBMarkQueueSet; 33 34 // A ptrQueue whose elements are "oops", pointers to object heads. 35 class ObjPtrQueue: public PtrQueue { 36 friend class Threads; 37 friend class SATBMarkQueueSet; 38 friend class G1RemarkThreadsClosure; 39 40 private: 41 // Filter out unwanted entries from the buffer. 42 void filter(); 43 44 // Apply the closure to all elements. 45 void apply_closure(ObjectClosure* cl); 46 47 // Apply the closure to all elements and empty the buffer; 48 void apply_closure_and_empty(ObjectClosure* cl); 49 50 // Apply the closure to all elements of "buf", down to "index" (inclusive.) 51 static void apply_closure_to_buffer(ObjectClosure* cl, 52 void** buf, size_t index, size_t sz); 53 54 public: 55 ObjPtrQueue(PtrQueueSet* qset, bool perm = false) : 56 // SATB queues are only active during marking cycles. We create 57 // them with their active field set to false. If a thread is 58 // created during a cycle and its SATB queue needs to be activated 59 // before the thread starts running, we'll need to set its active 60 // field to true. This is done in JavaThread::initialize_queues(). 61 PtrQueue(qset, perm, false /* active */) { } 62 63 // Process queue entries and free resources. 64 void flush(); 65 66 // Overrides PtrQueue::should_enqueue_buffer(). See the method's 67 // definition for more information. 68 virtual bool should_enqueue_buffer(); 69 70 #ifndef PRODUCT 71 // Helpful for debugging 72 void print(const char* name); 73 static void print(const char* name, void** buf, size_t index, size_t sz); 74 #endif // PRODUCT 75 }; 76 77 class SATBMarkQueueSet: public PtrQueueSet { 78 ObjectClosure* _closure; 79 ObjectClosure** _par_closures; // One per ParGCThread. 80 81 ObjPtrQueue _shared_satb_queue; 82 83 // Utility function to support sequential and parallel versions. If 84 // "par" is true, then "worker" is the par thread id; if "false", worker 85 // is ignored. 86 bool apply_closure_to_completed_buffer_work(bool par, uint worker); 87 88 #ifdef ASSERT 89 void dump_active_states(bool expected_active); 90 void verify_active_states(bool expected_active); 91 #endif // ASSERT 92 93 public: 94 SATBMarkQueueSet(); 95 96 void initialize(Monitor* cbl_mon, Mutex* fl_lock, 97 int process_completed_threshold, 98 Mutex* lock); 99 100 static void handle_zero_index_for_thread(JavaThread* t); 101 102 // Apply "set_active(active)" to all SATB queues in the set. It should be 103 // called only with the world stopped. The method will assert that the 104 // SATB queues of all threads it visits, as well as the SATB queue 105 // set itself, has an active value same as expected_active. 106 void set_active_all_threads(bool active, bool expected_active); 107 108 // Filter all the currently-active SATB buffers. 109 void filter_thread_buffers(); 110 111 // Register "blk" as "the closure" for all queues. Only one such closure 112 // is allowed. The "apply_closure_to_completed_buffer" method will apply 113 // this closure to a completed buffer, and "iterate_closure_all_threads" 114 // applies it to partially-filled buffers (the latter should only be done 115 // with the world stopped). 116 void set_closure(ObjectClosure* closure); 117 // Set the parallel closures: pointer is an array of pointers to 118 // closures, one for each parallel GC thread. 119 void set_par_closure(int i, ObjectClosure* closure); 120 121 // If there exists some completed buffer, pop it, then apply the 122 // registered closure to all its elements, and return true. If no 123 // completed buffers exist, return false. 124 bool apply_closure_to_completed_buffer() { 125 return apply_closure_to_completed_buffer_work(false, 0); 126 } 127 // Parallel version of the above. 128 bool par_apply_closure_to_completed_buffer(uint worker) { 129 return apply_closure_to_completed_buffer_work(true, worker); 130 } 131 132 // Apply the given closure on enqueued and currently-active buffers 133 // respectively. Both methods are read-only, i.e., they do not 134 // modify any of the buffers. 135 void iterate_completed_buffers_read_only(ObjectClosure* cl); 136 void iterate_thread_buffers_read_only(ObjectClosure* cl); 137 138 #ifndef PRODUCT 139 // Helpful for debugging 140 void print_all(const char* msg); 141 #endif // PRODUCT 142 143 ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; } 144 145 // If a marking is being abandoned, reset any unprocessed log buffers. 146 void abandon_partial_marking(); 147 }; 148 149 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP