1 /* 2 * Copyright (c) 2011, 2014, 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_HEAPREGIONSET_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP 27 28 #include "gc_implementation/g1/heapRegion.hpp" 29 30 // Large buffer for some cases where the output might be larger than normal. 31 #define HRS_ERR_MSG_BUFSZ 512 32 typedef FormatBuffer<HRS_ERR_MSG_BUFSZ> hrs_err_msg; 33 34 // Set verification will be forced either if someone defines 35 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which 36 // asserts are compiled in. 37 #ifndef HEAP_REGION_SET_FORCE_VERIFY 38 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT) 39 #endif // HEAP_REGION_SET_FORCE_VERIFY 40 41 class hrs_ext_msg; 42 43 class HRSMtSafeChecker : public CHeapObj<mtGC> { 44 public: 45 virtual void check() = 0; 46 }; 47 48 class MasterFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); }; 49 class SecondaryFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); }; 50 class HumongousRegionSetMtSafeChecker : public HRSMtSafeChecker { public: void check(); }; 51 class OldRegionSetMtSafeChecker : public HRSMtSafeChecker { public: void check(); }; 52 53 class HeapRegionSetCount VALUE_OBJ_CLASS_SPEC { 54 friend class VMStructs; 55 uint _length; 56 size_t _capacity; 57 58 public: 59 HeapRegionSetCount() : _length(0), _capacity(0) { } 60 61 const uint length() const { return _length; } 62 const size_t capacity() const { return _capacity; } 63 64 void increment(uint length_to_add, size_t capacity_to_add) { 65 _length += length_to_add; 66 _capacity += capacity_to_add; 67 } 68 69 void decrement(const uint length_to_remove, const size_t capacity_to_remove) { 70 _length -= length_to_remove; 71 _capacity -= capacity_to_remove; 72 } 73 }; 74 75 // Base class for all the classes that represent heap region sets. It 76 // contains the basic attributes that each set needs to maintain 77 // (e.g., length, region num, used bytes sum) plus any shared 78 // functionality (e.g., verification). 79 80 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC { 81 friend class VMStructs; 82 private: 83 bool _is_humongous; 84 bool _is_empty; 85 HRSMtSafeChecker* _mt_safety_checker; 86 87 protected: 88 // The number of regions added to the set. If the set contains 89 // only humongous regions, this reflects only 'starts humongous' 90 // regions and does not include 'continues humongous' ones. 91 HeapRegionSetCount _count; 92 93 const char* _name; 94 95 bool _verify_in_progress; 96 97 // verify_region() is used to ensure that the contents of a region 98 // added to / removed from a set are consistent. 99 void verify_region(HeapRegion* hr) PRODUCT_RETURN; 100 101 // Indicates whether all regions in the set should be humongous or 102 // not. Only used during verification. 103 bool regions_humongous() { return _is_humongous; } 104 105 // Indicates whether all regions in the set should be empty or 106 // not. Only used during verification. 107 bool regions_empty() { return _is_empty; } 108 109 void check_mt_safety() { 110 if (_mt_safety_checker != NULL) { 111 _mt_safety_checker->check(); 112 } 113 } 114 115 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { } 116 117 HeapRegionSetBase(const char* name, bool humongous, bool empty, HRSMtSafeChecker* mt_safety_checker); 118 119 public: 120 const char* name() { return _name; } 121 122 uint length() { return _count.length(); } 123 124 bool is_empty() { return _count.length() == 0; } 125 126 size_t total_capacity_bytes() { 127 return _count.capacity(); 128 } 129 130 // It updates the fields of the set to reflect hr being added to 131 // the set and tags the region appropriately. 132 inline void add(HeapRegion* hr); 133 134 // It updates the fields of the set to reflect hr being removed 135 // from the set and tags the region appropriately. 136 inline void remove(HeapRegion* hr); 137 138 // fill_in_ext_msg() writes the the values of the set's attributes 139 // in the custom err_msg (hrs_ext_msg). fill_in_ext_msg_extra() 140 // allows subclasses to append further information. 141 void fill_in_ext_msg(hrs_ext_msg* msg, const char* message); 142 143 virtual void verify(); 144 void verify_start(); 145 void verify_next_region(HeapRegion* hr); 146 void verify_end(); 147 148 #if HEAP_REGION_SET_FORCE_VERIFY 149 void verify_optional() { 150 verify(); 151 } 152 #else // HEAP_REGION_SET_FORCE_VERIFY 153 void verify_optional() { } 154 #endif // HEAP_REGION_SET_FORCE_VERIFY 155 156 virtual void print_on(outputStream* out, bool print_contents = false); 157 }; 158 159 // Customized err_msg for heap region sets. Apart from a 160 // assert/guarantee-specific message it also prints out the values of 161 // the fields of the associated set. This can be very helpful in 162 // diagnosing failures. 163 class hrs_ext_msg : public hrs_err_msg { 164 public: 165 hrs_ext_msg(HeapRegionSetBase* set, const char* message) : hrs_err_msg("%s","") { 166 set->fill_in_ext_msg(this, message); 167 } 168 }; 169 170 #define hrs_assert_sets_match(_set1_, _set2_) \ 171 do { \ 172 assert(((_set1_)->regions_humongous() == \ 173 (_set2_)->regions_humongous()) && \ 174 ((_set1_)->regions_empty() == (_set2_)->regions_empty()), \ 175 hrs_err_msg("the contents of set %s and set %s should match", \ 176 (_set1_)->name(), (_set2_)->name())); \ 177 } while (0) 178 179 // This class represents heap region sets whose members are not 180 // explicitly tracked. It's helpful to group regions using such sets 181 // so that we can reason about all the region groups in the heap using 182 // the same interface (namely, the HeapRegionSetBase API). 183 184 class HeapRegionSet : public HeapRegionSetBase { 185 public: 186 HeapRegionSet(const char* name, bool humongous, HRSMtSafeChecker* mt_safety_checker): 187 HeapRegionSetBase(name, humongous, false /* empty */, mt_safety_checker) { } 188 189 void bulk_remove(const HeapRegionSetCount& removed) { 190 _count.decrement(removed.length(), removed.capacity()); 191 } 192 }; 193 194 // A set that links all the regions added to it in a doubly-linked 195 // list. We should try to avoid doing operations that iterate over 196 // such lists in performance critical paths. Typically we should 197 // add / remove one region at a time or concatenate two lists. There are 198 // two ways to treat your lists, ordered and un-ordered. All un-ordered 199 // operations are done in constant time. To keep a list ordered only use 200 // add_ordered() to add elements to the list. If a list is not ordered 201 // from start, there is no way to sort it later. 202 203 class FreeRegionListIterator; 204 205 class FreeRegionList : public HeapRegionSetBase { 206 friend class FreeRegionListIterator; 207 208 private: 209 HeapRegion* _head; 210 HeapRegion* _tail; 211 212 // _last is used to keep track of where we added an element the last 213 // time in ordered lists. It helps to improve performance when adding 214 // several ordered items in a row. 215 HeapRegion* _last; 216 217 static uint _unrealistically_long_length; 218 219 void add_as_head_or_tail(FreeRegionList* from_list, bool as_head); 220 221 protected: 222 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg); 223 224 // See the comment for HeapRegionSetBase::clear() 225 virtual void clear(); 226 227 public: 228 FreeRegionList(const char* name, HRSMtSafeChecker* mt_safety_checker = NULL): 229 HeapRegionSetBase(name, false /* humongous */, true /* empty */, mt_safety_checker) { 230 clear(); 231 } 232 233 void verify_list(); 234 235 HeapRegion* head() { return _head; } 236 HeapRegion* tail() { return _tail; } 237 238 static void set_unrealistically_long_length(uint len); 239 240 // Add hr to the list. The region should not be a member of another set. 241 // Assumes that the list is ordered and will preserve that order. The order 242 // is determined by hrs_index. 243 inline void add_ordered(HeapRegion* hr); 244 245 // It adds hr to the list as the new head. The region should not be 246 // a member of another set. 247 inline void add_as_head(HeapRegion* hr); 248 249 // It adds hr to the list as the new tail. The region should not be 250 // a member of another set. 251 inline void add_as_tail(HeapRegion* hr); 252 253 // It removes and returns the head of the list. It assumes that the 254 // list is not empty so it will return a non-NULL value. 255 inline HeapRegion* remove_head(); 256 257 // Convenience method. 258 inline HeapRegion* remove_head_or_null(); 259 260 // Removes and returns the last element (_tail) of the list. It assumes 261 // that the list isn't empty so that it can return a non-NULL value. 262 inline HeapRegion* remove_tail(); 263 264 // Convenience method 265 inline HeapRegion* remove_tail_or_null(); 266 267 // Removes from head or tail based on the given argument. 268 inline HeapRegion* remove_region(bool from_head); 269 270 // Merge two ordered lists. The result is also ordered. The order is 271 // determined by hrs_index. 272 void add_ordered(FreeRegionList* from_list); 273 274 // It moves the regions from from_list to this list and empties 275 // from_list. The new regions will appear in the same order as they 276 // were in from_list and be linked in the beginning of this list. 277 void add_as_head(FreeRegionList* from_list); 278 279 // It moves the regions from from_list to this list and empties 280 // from_list. The new regions will appear in the same order as they 281 // were in from_list and be linked in the end of this list. 282 void add_as_tail(FreeRegionList* from_list); 283 284 // It empties the list by removing all regions from it. 285 void remove_all(); 286 287 // It removes all regions in the list that are pending for removal 288 // (i.e., they have been tagged with "pending_removal"). The list 289 // must not be empty, target_count should reflect the exact number 290 // of regions that are pending for removal in the list, and 291 // target_count should be > 1 (currently, we never need to remove a 292 // single region using this). 293 void remove_all_pending(uint target_count); 294 295 virtual void verify(); 296 297 virtual void print_on(outputStream* out, bool print_contents = false); 298 }; 299 300 // Iterator class that provides a convenient way to iterate over the 301 // regions of a HeapRegionLinkedList instance. 302 303 class FreeRegionListIterator : public StackObj { 304 private: 305 FreeRegionList* _list; 306 HeapRegion* _curr; 307 308 public: 309 bool more_available() { 310 return _curr != NULL; 311 } 312 313 HeapRegion* get_next() { 314 assert(more_available(), 315 "get_next() should be called when more regions are available"); 316 317 // If we are going to introduce a count in the iterator we should 318 // do the "cycle" check. 319 320 HeapRegion* hr = _curr; 321 _list->verify_region(hr); 322 _curr = hr->next(); 323 return hr; 324 } 325 326 FreeRegionListIterator(FreeRegionList* list) : _curr(NULL), _list(list) { 327 _curr = list->head(); 328 } 329 }; 330 331 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP