1 /* 2 * Copyright (c) 2001, 2013, 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_implementation/g1/heapRegion.hpp" 27 #include "gc_implementation/g1/heapRegionSeq.inline.hpp" 28 #include "gc_implementation/g1/heapRegionSet.hpp" 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 30 #include "memory/allocation.hpp" 31 32 // Private 33 34 uint HeapRegionSeq::find_contiguous_from(uint from, uint num) { 35 uint len = length(); 36 assert(num > 1, "use this only for sequences of length 2 or greater"); 37 assert(from <= len, 38 err_msg("from: %u should be valid and <= than %u", from, len)); 39 40 uint curr = from; 41 uint first = G1_NULL_HRS_INDEX; 42 uint num_so_far = 0; 43 while (curr < len && num_so_far < num) { 44 if (at(curr)->is_empty()) { 45 if (first == G1_NULL_HRS_INDEX) { 46 first = curr; 47 num_so_far = 1; 48 } else { 49 num_so_far += 1; 50 } 51 } else { 52 first = G1_NULL_HRS_INDEX; 53 num_so_far = 0; 54 } 55 curr += 1; 56 } 57 assert(num_so_far <= num, "post-condition"); 58 if (num_so_far == num) { 59 // we found enough space for the humongous object 60 assert(from <= first && first < len, "post-condition"); 61 assert(first < curr && (curr - first) == num, "post-condition"); 62 for (uint i = first; i < first + num; ++i) { 63 assert(at(i)->is_empty(), "post-condition"); 64 } 65 return first; 66 } else { 67 // we failed to find enough space for the humongous object 68 return G1_NULL_HRS_INDEX; 69 } 70 } 71 72 // Public 73 74 void HeapRegionSeq::initialize(HeapWord* bottom, HeapWord* end) { 75 assert((uintptr_t) bottom % HeapRegion::GrainBytes == 0, 76 "bottom should be heap region aligned"); 77 assert((uintptr_t) end % HeapRegion::GrainBytes == 0, 78 "end should be heap region aligned"); 79 80 _next_search_index = 0; 81 _allocated_length = 0; 82 83 _regions.initialize(bottom, end, HeapRegion::GrainBytes); 84 } 85 86 MemRegion HeapRegionSeq::expand_by(HeapWord* old_end, 87 HeapWord* new_end, 88 FreeRegionList* list) { 89 assert(old_end < new_end, "don't call it otherwise"); 90 G1CollectedHeap* g1h = G1CollectedHeap::heap(); 91 92 HeapWord* next_bottom = old_end; 93 assert(heap_bottom() <= next_bottom, "invariant"); 94 while (next_bottom < new_end) { 95 assert(next_bottom < heap_end(), "invariant"); 96 uint index = length(); 97 98 assert(index < max_length(), "otherwise we cannot expand further"); 99 if (index == 0) { 100 // We have not allocated any regions so far 101 assert(next_bottom == heap_bottom(), "invariant"); 102 } else { 103 // next_bottom should match the end of the last/previous region 104 assert(next_bottom == at(index - 1)->end(), "invariant"); 105 } 106 107 if (index == _allocated_length) { 108 // We have to allocate a new HeapRegion. 109 HeapRegion* new_hr = g1h->new_heap_region(index, next_bottom); 110 if (new_hr == NULL) { 111 // allocation failed, we bail out and return what we have done so far 112 return MemRegion(old_end, next_bottom); 113 } 114 assert(_regions.get_by_index(index) == NULL, "invariant"); 115 _regions.set_by_index(index, new_hr); 116 increment_allocated_length(); 117 } 118 // Have to increment the length first, otherwise we will get an 119 // assert failure at(index) below. 120 increment_length(); 121 HeapRegion* hr = at(index); 122 list->add_as_tail(hr); 123 124 next_bottom = hr->end(); 125 } 126 assert(next_bottom == new_end, "post-condition"); 127 return MemRegion(old_end, next_bottom); 128 } 129 130 uint HeapRegionSeq::free_suffix() { 131 uint res = 0; 132 uint index = length(); 133 while (index > 0) { 134 index -= 1; 135 if (!at(index)->is_empty()) { 136 break; 137 } 138 res += 1; 139 } 140 return res; 141 } 142 143 uint HeapRegionSeq::find_contiguous(uint num) { 144 assert(num > 1, "use this only for sequences of length 2 or greater"); 145 assert(_next_search_index <= length(), 146 err_msg("_next_search_index: %u should be valid and <= than %u", 147 _next_search_index, length())); 148 149 uint start = _next_search_index; 150 uint res = find_contiguous_from(start, num); 151 if (res == G1_NULL_HRS_INDEX && start > 0) { 152 // Try starting from the beginning. If _next_search_index was 0, 153 // no point in doing this again. 154 res = find_contiguous_from(0, num); 155 } 156 if (res != G1_NULL_HRS_INDEX) { 157 assert(res < length(), err_msg("res: %u should be valid", res)); 158 _next_search_index = res + num; 159 assert(_next_search_index <= length(), 160 err_msg("_next_search_index: %u should be valid and <= than %u", 161 _next_search_index, length())); 162 } 163 return res; 164 } 165 166 void HeapRegionSeq::iterate(HeapRegionClosure* blk) const { 167 iterate_from((HeapRegion*) NULL, blk); 168 } 169 170 void HeapRegionSeq::iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const { 171 uint hr_index = 0; 172 if (hr != NULL) { 173 hr_index = hr->hrs_index(); 174 } 175 176 uint len = length(); 177 for (uint i = hr_index; i < len; i += 1) { 178 bool res = blk->doHeapRegion(at(i)); 179 if (res) { 180 blk->incomplete(); 181 return; 182 } 183 } 184 for (uint i = 0; i < hr_index; i += 1) { 185 bool res = blk->doHeapRegion(at(i)); 186 if (res) { 187 blk->incomplete(); 188 return; 189 } 190 } 191 } 192 193 uint HeapRegionSeq::shrink_by(uint num_regions_to_remove) { 194 // Reset this in case it's currently pointing into the regions that 195 // we just removed. 196 _next_search_index = 0; 197 198 assert(length() > 0, "the region sequence should not be empty"); 199 assert(length() <= _allocated_length, "invariant"); 200 assert(_allocated_length > 0, "we should have at least one region committed"); 201 assert(num_regions_to_remove < length(), "We should never remove all regions"); 202 203 uint i = 0; 204 for (; i < num_regions_to_remove; i++) { 205 HeapRegion* cur = at(length() - 1); 206 207 if (!cur->is_empty()) { 208 // We have to give up if the region can not be moved 209 break; 210 } 211 assert(!cur->isHumongous(), "Humongous regions should not be empty"); 212 213 decrement_length(); 214 } 215 return i; 216 } 217 218 #ifndef PRODUCT 219 void HeapRegionSeq::verify_optional() { 220 guarantee(length() <= _allocated_length, 221 err_msg("invariant: _length: %u _allocated_length: %u", 222 length(), _allocated_length)); 223 guarantee(_allocated_length <= max_length(), 224 err_msg("invariant: _allocated_length: %u _max_length: %u", 225 _allocated_length, max_length())); 226 guarantee(_next_search_index <= length(), 227 err_msg("invariant: _next_search_index: %u _length: %u", 228 _next_search_index, length())); 229 230 HeapWord* prev_end = heap_bottom(); 231 for (uint i = 0; i < _allocated_length; i += 1) { 232 HeapRegion* hr = _regions.get_by_index(i); 233 guarantee(hr != NULL, err_msg("invariant: i: %u", i)); 234 guarantee(hr->bottom() == prev_end, 235 err_msg("invariant i: %u "HR_FORMAT" prev_end: "PTR_FORMAT, 236 i, HR_FORMAT_PARAMS(hr), prev_end)); 237 guarantee(hr->hrs_index() == i, 238 err_msg("invariant: i: %u hrs_index(): %u", i, hr->hrs_index())); 239 if (i < length()) { 240 // Asserts will fire if i is >= _length 241 HeapWord* addr = hr->bottom(); 242 guarantee(addr_to_region(addr) == hr, "sanity"); 243 guarantee(addr_to_region_unsafe(addr) == hr, "sanity"); 244 } else { 245 guarantee(hr->is_empty(), "sanity"); 246 guarantee(!hr->isHumongous(), "sanity"); 247 // using assert instead of guarantee here since containing_set() 248 // is only available in non-product builds. 249 assert(hr->containing_set() == NULL, "sanity"); 250 } 251 if (hr->startsHumongous()) { 252 prev_end = hr->orig_end(); 253 } else { 254 prev_end = hr->end(); 255 } 256 } 257 for (uint i = _allocated_length; i < max_length(); i += 1) { 258 guarantee(_regions.get_by_index(i) == NULL, err_msg("invariant i: %u", i)); 259 } 260 } 261 #endif // PRODUCT