1 /* 2 * Copyright (c) 2014, 2015, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHMARKCOMPACT_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHMARKCOMPACT_HPP 26 27 #include "gc/serial/genMarkSweep.hpp" 28 #include "gc/shared/taskqueue.hpp" 29 #include "gc/shared/workgroup.hpp" 30 #include "gc/shenandoah/shenandoahHeap.hpp" 31 32 class HeapWord; 33 34 /** 35 * This implements full-GC (e.g. when invoking System.gc() ) using a 36 * mark-compact algorithm. It's implemented in four phases: 37 * 38 * 1. Mark all live objects of the heap by traversing objects starting at GC roots. 39 * 2. Calculate the new location of each live object. This is done by sequentially scanning 40 * the heap, keeping track of a next-location-pointer, which is then written to each 41 * object's brooks ptr field. 42 * 3. Update all references. This is implemented by another scan of the heap, and updates 43 * all references in live objects by what's stored in the target object's brooks ptr. 44 * 3. Compact the heap by copying all live objects to their new location. 45 */ 46 47 class ShenandoahMarkCompact: AllStatic { 48 49 public: 50 51 static void do_mark_compact(); 52 53 private: 54 55 static void phase1_mark_heap(); 56 static void phase2_calculate_target_addresses(); 57 static void phase3_update_references(); 58 static void phase4_compact_objects(); 59 static void finish_compaction(HeapWord* last_addr); 60 61 static void allocate_stacks(); 62 }; 63 64 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHMARKCOMPACT_HPP