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 "memory/allocation.hpp" 29 #include "gc_implementation/g1/ptrQueue.hpp" 30 31 class JavaThread; 32 class SATBMarkQueueSet; 33 34 // Base class for processing the contents of a SATB buffer. 35 class SATBBufferClosure : public StackObj { 36 protected: 37 ~SATBBufferClosure() { } 38 39 public: 40 // Process the SATB entries in the designated buffer range. 41 virtual void do_buffer(void** buffer, size_t size) = 0; 42 }; 43 44 // A ptrQueue whose elements are "oops", pointers to object heads. 45 class ObjPtrQueue: public PtrQueue { 46 friend class SATBMarkQueueSet; 47 48 private: 49 // Filter out unwanted entries from the buffer. 50 void filter(); 51 52 template <class HeapType> 53 void filter_impl(); 54 55 public: 56 ObjPtrQueue(PtrQueueSet* qset, bool perm = false) : 57 // SATB queues are only active during marking cycles. We create 58 // them with their active field set to false. If a thread is 59 // created during a cycle and its SATB queue needs to be activated 60 // before the thread starts running, we'll need to set its active 61 // field to true. This is done in JavaThread::initialize_queues(). 62 PtrQueue(qset, perm, false /* active */) { } 63 64 // Process queue entries and free resources. 65 void flush(); 66 67 // Apply cl to the active part of the buffer. 68 // Prerequisite: Must be at a safepoint. 69 void apply_closure_and_empty(SATBBufferClosure* cl); 70 71 // Overrides PtrQueue::should_enqueue_buffer(). See the method's 72 // definition for more information. 73 virtual bool should_enqueue_buffer(); 74 75 #ifndef PRODUCT 76 // Helpful for debugging 77 void print(const char* name); 78 static void print(const char* name, void** buf, size_t index, size_t sz); 79 #endif // PRODUCT 80 }; 81 82 class SATBMarkQueueSet: public PtrQueueSet { 83 ObjPtrQueue _shared_satb_queue; 84 85 #ifdef ASSERT 86 void dump_active_states(bool expected_active); 87 void verify_active_states(bool expected_active); 88 #endif // ASSERT 89 90 public: 91 SATBMarkQueueSet(); 92 93 void initialize(Monitor* cbl_mon, Mutex* fl_lock, 94 int process_completed_threshold, 95 Mutex* lock); 96 97 static void handle_zero_index_for_thread(JavaThread* t); 98 99 // Apply "set_active(active)" to all SATB queues in the set. It should be 100 // called only with the world stopped. The method will assert that the 101 // SATB queues of all threads it visits, as well as the SATB queue 102 // set itself, has an active value same as expected_active. 103 void set_active_all_threads(bool active, bool expected_active); 104 105 // Filter all the currently-active SATB buffers. 106 void filter_thread_buffers(); 107 108 // If there exists some completed buffer, pop and process it, and 109 // return true. Otherwise return false. Processing a buffer 110 // consists of applying the closure to the buffer range starting 111 // with the first non-NULL entry to the end of the buffer; the 112 // leading entries may be NULL due to filtering. 113 bool apply_closure_to_completed_buffer(SATBBufferClosure* cl); 114 115 #ifndef PRODUCT 116 // Helpful for debugging 117 void print_all(const char* msg); 118 #endif // PRODUCT 119 120 ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; } 121 122 // If a marking is being abandoned, reset any unprocessed log buffers. 123 void abandon_partial_marking(); 124 }; 125 126 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP