1 /* 2 * Copyright (c) 2001, 2010, 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_BUFFERINGOOPCLOSURE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP 27 28 #include "memory/genOopClosures.hpp" 29 #include "memory/generation.hpp" 30 #include "runtime/os.hpp" 31 #include "utilities/taskqueue.hpp" 32 33 // A BufferingOops closure tries to separate out the cost of finding roots 34 // from the cost of applying closures to them. It maintains an array of 35 // ref-containing locations. Until the array is full, applying the closure 36 // to an oop* merely records that location in the array. Since this 37 // closure app cost is small, an elapsed timer can approximately attribute 38 // all of this cost to the cost of finding the roots. When the array fills 39 // up, the wrapped closure is applied to all elements, keeping track of 40 // this elapsed time of this process, and leaving the array empty. 41 // The caller must be sure to call "done" to process any unprocessed 42 // buffered entriess. 43 44 class Generation; 45 class HeapRegion; 46 47 class BufferingOopClosure: public OopClosure { 48 protected: 49 enum PrivateConstants { 50 BufferLength = 1024 51 }; 52 53 StarTask _buffer[BufferLength]; 54 StarTask* _buffer_top; 55 StarTask* _buffer_curr; 56 57 OopClosure* _oc; 58 double _closure_app_seconds; 59 60 void process_buffer () { 61 double start = os::elapsedTime(); 62 for (StarTask* curr = _buffer; curr < _buffer_curr; ++curr) { 63 if (curr->is_narrow()) { 64 assert(UseCompressedOops, "Error"); 65 _oc->do_oop((narrowOop*)(*curr)); 66 } else { 67 _oc->do_oop((oop*)(*curr)); 68 } 69 } 70 _buffer_curr = _buffer; 71 _closure_app_seconds += (os::elapsedTime() - start); 72 } 73 74 template <class T> inline void do_oop_work(T* p) { 75 if (_buffer_curr == _buffer_top) { 76 process_buffer(); 77 } 78 StarTask new_ref(p); 79 *_buffer_curr = new_ref; 80 ++_buffer_curr; 81 } 82 83 public: 84 virtual void do_oop(narrowOop* p) { do_oop_work(p); } 85 virtual void do_oop(oop* p) { do_oop_work(p); } 86 87 void done () { 88 if (_buffer_curr > _buffer) { 89 process_buffer(); 90 } 91 } 92 double closure_app_seconds () { 93 return _closure_app_seconds; 94 } 95 BufferingOopClosure (OopClosure *oc) : 96 _oc(oc), 97 _buffer_curr(_buffer), _buffer_top(_buffer + BufferLength), 98 _closure_app_seconds(0.0) { } 99 }; 100 101 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_BUFFERINGOOPCLOSURE_HPP