1 /* 2 * Copyright (c) 2001, 2009, 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 // The Concurrent ZF Thread. Performs concurrent zero-filling. 26 27 class ConcurrentZFThread: public ConcurrentGCThread { 28 friend class VMStructs; 29 friend class ZeroFillRegionClosure; 30 31 private: 32 33 // Zero fill the heap region. 34 void processHeapRegion(HeapRegion* r); 35 36 // Stats 37 // Allocation (protected by heap lock). 38 static int _region_allocs; // Number of regions allocated 39 static int _sync_zfs; // Synchronous zero-fills + 40 static int _zf_waits; // Wait for conc zero-fill completion. 41 42 // Number of regions CFZ thread fills. 43 static int _regions_filled; 44 45 double _vtime_start; // Initial virtual time. 46 47 // These are static because the "print_summary_info" method is, and 48 // it currently assumes there is only one ZF thread. We'll change when 49 // we need to. 50 static double _vtime_accum; // Initial virtual time. 51 static double vtime_accum() { return _vtime_accum; } 52 53 // Offer yield for GC. Returns true if yield occurred. 54 bool offer_yield(); 55 56 public: 57 // Constructor 58 ConcurrentZFThread(); 59 60 // Main loop. 61 virtual void run(); 62 63 // Printing 64 void print_on(outputStream* st) const; 65 void print() const; 66 67 // Waits until "r" has been zero-filled. Requires caller to hold the 68 // ZF_mon. 69 static void wait_for_ZF_completed(HeapRegion* r); 70 71 // Get or clear the current unclean region. Should be done 72 // while holding the ZF_needed_mon lock. 73 74 // shutdown 75 void stop(); 76 77 // Stats 78 static void note_region_alloc() {_region_allocs++; } 79 static void note_sync_zfs() { _sync_zfs++; } 80 static void note_zf_wait() { _zf_waits++; } 81 static void note_region_filled() { _regions_filled++; } 82 83 static void print_summary_info(); 84 };