1 /* 2 * Copyright (c) 2001, 2016, 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 #include "precompiled.hpp" 26 #include "gc/parallel/objectStartArray.inline.hpp" 27 #include "gc/shared/cardTableModRefBS.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "oops/oop.inline.hpp" 30 #include "runtime/java.hpp" 31 #include "services/memTracker.hpp" 32 33 void ObjectStartArray::initialize(MemRegion reserved_region) { 34 // We're based on the assumption that we use the same 35 // size blocks as the card table. 36 assert((int)block_size == (int)CardTable::card_size, "Sanity"); 37 assert((int)block_size <= 512, "block_size must be less than or equal to 512"); 38 39 // Calculate how much space must be reserved 40 _reserved_region = reserved_region; 41 42 size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words; 43 assert(bytes_to_reserve > 0, "Sanity"); 44 45 bytes_to_reserve = 46 align_size_up(bytes_to_reserve, os::vm_allocation_granularity()); 47 48 // Do not use large-pages for the backing store. The one large page region 49 // will be used for the heap proper. 50 ReservedSpace backing_store(bytes_to_reserve); 51 if (!backing_store.is_reserved()) { 52 vm_exit_during_initialization("Could not reserve space for ObjectStartArray"); 53 } 54 MemTracker::record_virtual_memory_type((address)backing_store.base(), mtGC); 55 56 // We do not commit any memory initially 57 if (!_virtual_space.initialize(backing_store, 0)) { 58 vm_exit_during_initialization("Could not commit space for ObjectStartArray"); 59 } 60 61 _raw_base = (jbyte*)_virtual_space.low_boundary(); 62 63 if (_raw_base == NULL) { 64 vm_exit_during_initialization("Could not get raw_base address"); 65 } 66 67 MemTracker::record_virtual_memory_type((address)_raw_base, mtGC); 68 69 70 _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift); 71 72 _covered_region.set_start(reserved_region.start()); 73 _covered_region.set_word_size(0); 74 75 _blocks_region.set_start((HeapWord*)_raw_base); 76 _blocks_region.set_word_size(0); 77 } 78 79 void ObjectStartArray::set_covered_region(MemRegion mr) { 80 assert(_reserved_region.contains(mr), "MemRegion outside of reserved space"); 81 assert(_reserved_region.start() == mr.start(), "Attempt to move covered region"); 82 83 HeapWord* low_bound = mr.start(); 84 HeapWord* high_bound = mr.end(); 85 assert((uintptr_t(low_bound) & (block_size - 1)) == 0, "heap must start at block boundary"); 86 assert((uintptr_t(high_bound) & (block_size - 1)) == 0, "heap must end at block boundary"); 87 88 size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words; 89 90 // Only commit memory in page sized chunks 91 requested_blocks_size_in_bytes = 92 align_size_up(requested_blocks_size_in_bytes, os::vm_page_size()); 93 94 _covered_region = mr; 95 96 size_t current_blocks_size_in_bytes = _blocks_region.byte_size(); 97 98 if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) { 99 // Expand 100 size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes; 101 if (!_virtual_space.expand_by(expand_by)) { 102 vm_exit_out_of_memory(expand_by, OOM_MMAP_ERROR, "object start array expansion"); 103 } 104 // Clear *only* the newly allocated region 105 memset(_blocks_region.end(), clean_block, expand_by); 106 } 107 108 if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) { 109 // Shrink 110 size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes; 111 _virtual_space.shrink_by(shrink_by); 112 } 113 114 _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord)); 115 116 assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment"); 117 assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity"); 118 assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map"); 119 assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map"); 120 } 121 122 void ObjectStartArray::reset() { 123 memset(_blocks_region.start(), clean_block, _blocks_region.byte_size()); 124 } 125 126 bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr, 127 HeapWord* end_addr) const { 128 assert(start_addr <= end_addr, 129 "Range is wrong. start_addr (" PTR_FORMAT ") is after end_addr (" PTR_FORMAT ")", 130 p2i(start_addr), p2i(end_addr)); 131 if (start_addr > end_addr) { 132 return false; 133 } 134 135 jbyte* start_block = block_for_addr(start_addr); 136 jbyte* end_block = block_for_addr(end_addr); 137 138 for (jbyte* block = start_block; block <= end_block; block++) { 139 if (*block != clean_block) { 140 return true; 141 } 142 } 143 144 return false; 145 }