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_HEAPREGIONSEQ_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP 27 28 #include "gc_implementation/g1/heapRegion.hpp" 29 #include "utilities/growableArray.hpp" 30 31 class HeapRegion; 32 class HeapRegionClosure; 33 34 class HeapRegionSeq: public CHeapObj { 35 36 // _regions is kept sorted by start address order, and no two regions are 37 // overlapping. 38 GrowableArray<HeapRegion*> _regions; 39 40 // The index in "_regions" at which to start the next allocation search. 41 // (For efficiency only; private to obj_allocate after initialization.) 42 int _alloc_search_start; 43 44 // Attempts to allocate a block of the (assumed humongous) word_size, 45 // starting at the region "ind". 46 HeapWord* alloc_obj_from_region_index(int ind, size_t word_size); 47 48 // Currently, we're choosing collection sets in a round-robin fashion, 49 // starting here. 50 int _next_rr_candidate; 51 52 // The bottom address of the bottom-most region, or else NULL if there 53 // are no regions in the sequence. 54 char* _seq_bottom; 55 56 public: 57 // Initializes "this" to the empty sequence of regions. 58 HeapRegionSeq(const size_t max_size); 59 60 // Adds "hr" to "this" sequence. Requires "hr" not to overlap with 61 // any region already in "this". (Will perform better if regions are 62 // inserted in ascending address order.) 63 void insert(HeapRegion* hr); 64 65 // Given a HeapRegion*, returns its index within _regions, 66 // or returns -1 if not found. 67 int find(HeapRegion* hr); 68 69 // Requires the index to be valid, and return the region at the index. 70 HeapRegion* at(size_t i) { return _regions.at((int)i); } 71 72 // Return the number of regions in the sequence. 73 size_t length(); 74 75 // Returns the number of contiguous regions at the end of the sequence 76 // that are available for allocation. 77 size_t free_suffix(); 78 79 // Requires "word_size" to be humongous (in the technical sense). If 80 // possible, allocates a contiguous subsequence of the heap regions to 81 // satisfy the allocation, and returns the address of the beginning of 82 // that sequence, otherwise returns NULL. 83 HeapWord* obj_allocate(size_t word_size); 84 85 // Apply the "doHeapRegion" method of "blk" to all regions in "this", 86 // in address order, terminating the iteration early 87 // if the "doHeapRegion" method returns "true". 88 void iterate(HeapRegionClosure* blk); 89 90 // Apply the "doHeapRegion" method of "blk" to all regions in "this", 91 // starting at "r" (or first region, if "r" is NULL), in a circular 92 // manner, terminating the iteration early if the "doHeapRegion" method 93 // returns "true". 94 void iterate_from(HeapRegion* r, HeapRegionClosure* blk); 95 96 // As above, but start from a given index in the sequence 97 // instead of a given heap region. 98 void iterate_from(int idx, HeapRegionClosure* blk); 99 100 // Requires "shrink_bytes" to be a multiple of the page size and heap 101 // region granularity. Deletes as many "rightmost" completely free heap 102 // regions from the sequence as comprise shrink_bytes bytes. Returns the 103 // MemRegion indicating the region those regions comprised, and sets 104 // "num_regions_deleted" to the number of regions deleted. 105 MemRegion shrink_by(size_t shrink_bytes, size_t& num_regions_deleted); 106 107 // If "addr" falls within a region in the sequence, return that region, 108 // or else NULL. 109 HeapRegion* addr_to_region(const void* addr); 110 111 void print(); 112 113 // Prints out runs of empty regions. 114 void print_empty_runs(); 115 116 }; 117 118 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP