1 /* 2 * Copyright (c) 2001, 2015, 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/g1/g1BiasedArray.hpp" 27 #include "gc/g1/g1RegionToSpaceMapper.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "memory/virtualspace.hpp" 30 #include "services/memTracker.hpp" 31 #include "utilities/bitMap.inline.hpp" 32 33 G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs, 34 size_t used_size, 35 size_t page_size, 36 size_t region_granularity, 37 size_t commit_factor, 38 MemoryType type) : 39 _storage(rs, used_size, page_size), 40 _region_granularity(region_granularity), 41 _listener(NULL), 42 _commit_map(rs.size() * commit_factor / region_granularity, mtGC) { 43 guarantee(is_power_of_2(page_size), "must be"); 44 guarantee(is_power_of_2(region_granularity), "must be"); 45 46 MemTracker::record_virtual_memory_type((address)rs.base(), type); 47 } 48 49 // G1RegionToSpaceMapper implementation where the region granularity is larger than 50 // or the same as the commit granularity. 51 // Basically, the space corresponding to one region region spans several OS pages. 52 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper { 53 private: 54 size_t _pages_per_region; 55 56 public: 57 G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs, 58 size_t actual_size, 59 size_t page_size, 60 size_t alloc_granularity, 61 size_t commit_factor, 62 MemoryType type) : 63 G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type), 64 _pages_per_region(alloc_granularity / (page_size * commit_factor)) { 65 66 guarantee(alloc_granularity >= page_size, "allocation granularity smaller than commit granularity"); 67 } 68 69 virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) { 70 size_t const start_page = (size_t)start_idx * _pages_per_region; 71 bool zero_filled = _storage.commit(start_page, num_regions * _pages_per_region); 72 if (AlwaysPreTouch) { 73 _storage.pretouch(start_page, num_regions * _pages_per_region, pretouch_gang); 74 } 75 _commit_map.set_range(start_idx, start_idx + num_regions); 76 fire_on_commit(start_idx, num_regions, zero_filled); 77 } 78 79 virtual void uncommit_regions(uint start_idx, size_t num_regions) { 80 _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region); 81 _commit_map.clear_range(start_idx, start_idx + num_regions); 82 } 83 }; 84 85 // G1RegionToSpaceMapper implementation where the region granularity is smaller 86 // than the commit granularity. 87 // Basically, the contents of one OS page span several regions. 88 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper { 89 private: 90 class CommitRefcountArray : public G1BiasedMappedArray<uint> { 91 protected: 92 virtual uint default_value() const { return 0; } 93 }; 94 95 size_t _regions_per_page; 96 97 CommitRefcountArray _refcounts; 98 99 uintptr_t region_idx_to_page_idx(uint region) const { 100 return region / _regions_per_page; 101 } 102 103 public: 104 G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs, 105 size_t actual_size, 106 size_t page_size, 107 size_t alloc_granularity, 108 size_t commit_factor, 109 MemoryType type) : 110 G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type), 111 _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() { 112 113 guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity"); 114 _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_size_up(rs.size(), page_size)), page_size); 115 } 116 117 virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) { 118 size_t const NoPage = ~(size_t)0; 119 120 size_t first_committed = NoPage; 121 size_t num_committed = 0; 122 123 bool all_zero_filled = true; 124 125 for (uint i = start_idx; i < start_idx + num_regions; i++) { 126 assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i); 127 size_t idx = region_idx_to_page_idx(i); 128 uint old_refcount = _refcounts.get_by_index(idx); 129 130 bool zero_filled = false; 131 if (old_refcount == 0) { 132 if (first_committed == NoPage) { 133 first_committed = idx; 134 num_committed = 1; 135 } else { 136 num_committed++; 137 } 138 zero_filled = _storage.commit(idx, 1); 139 } 140 all_zero_filled &= zero_filled; 141 142 _refcounts.set_by_index(idx, old_refcount + 1); 143 _commit_map.set_bit(i); 144 } 145 if (AlwaysPreTouch && num_committed > 0) { 146 _storage.pretouch(first_committed, num_committed, pretouch_gang); 147 } 148 fire_on_commit(start_idx, num_regions, all_zero_filled); 149 } 150 151 virtual void uncommit_regions(uint start_idx, size_t num_regions) { 152 for (uint i = start_idx; i < start_idx + num_regions; i++) { 153 assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i); 154 size_t idx = region_idx_to_page_idx(i); 155 uint old_refcount = _refcounts.get_by_index(idx); 156 assert(old_refcount > 0, "must be"); 157 if (old_refcount == 1) { 158 _storage.uncommit(idx, 1); 159 } 160 _refcounts.set_by_index(idx, old_refcount - 1); 161 _commit_map.clear_bit(i); 162 } 163 } 164 }; 165 166 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) { 167 if (_listener != NULL) { 168 _listener->on_commit(start_idx, num_regions, zero_filled); 169 } 170 } 171 172 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs, 173 size_t actual_size, 174 size_t page_size, 175 size_t region_granularity, 176 size_t commit_factor, 177 MemoryType type) { 178 179 if (region_granularity >= (page_size * commit_factor)) { 180 return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type); 181 } else { 182 return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type); 183 } 184 }