Mon, 26 Jan 2009 12:47:21 -0800
6786503: Overflow list performance can be improved
Summary: Avoid overflow list walk in CMS & ParNew when it is unnecessary. Fix a couple of correctness issues, including a C-heap leak, in ParNew at the intersection of promotion failure, work queue overflow and object array chunking. Add stress testing option and related assertion checking.
Reviewed-by: jmasa
duke@435 | 1 | /* |
xdono@631 | 2 | * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | class EdenSpace; |
duke@435 | 26 | class ContiguousSpace; |
coleenp@548 | 27 | class ScanClosure; |
duke@435 | 28 | |
duke@435 | 29 | // DefNewGeneration is a young generation containing eden, from- and |
duke@435 | 30 | // to-space. |
duke@435 | 31 | |
duke@435 | 32 | class DefNewGeneration: public Generation { |
duke@435 | 33 | friend class VMStructs; |
duke@435 | 34 | |
duke@435 | 35 | protected: |
duke@435 | 36 | Generation* _next_gen; |
duke@435 | 37 | int _tenuring_threshold; // Tenuring threshold for next collection. |
duke@435 | 38 | ageTable _age_table; |
duke@435 | 39 | // Size of object to pretenure in words; command line provides bytes |
duke@435 | 40 | size_t _pretenure_size_threshold_words; |
duke@435 | 41 | |
duke@435 | 42 | ageTable* age_table() { return &_age_table; } |
duke@435 | 43 | // Initialize state to optimistically assume no promotion failure will |
duke@435 | 44 | // happen. |
duke@435 | 45 | void init_assuming_no_promotion_failure(); |
duke@435 | 46 | // True iff a promotion has failed in the current collection. |
duke@435 | 47 | bool _promotion_failed; |
duke@435 | 48 | bool promotion_failed() { return _promotion_failed; } |
duke@435 | 49 | |
duke@435 | 50 | // Handling promotion failure. A young generation collection |
duke@435 | 51 | // can fail if a live object cannot be copied out of its |
duke@435 | 52 | // location in eden or from-space during the collection. If |
duke@435 | 53 | // a collection fails, the young generation is left in a |
duke@435 | 54 | // consistent state such that it can be collected by a |
duke@435 | 55 | // full collection. |
duke@435 | 56 | // Before the collection |
duke@435 | 57 | // Objects are in eden or from-space |
duke@435 | 58 | // All roots into the young generation point into eden or from-space. |
duke@435 | 59 | // |
duke@435 | 60 | // After a failed collection |
duke@435 | 61 | // Objects may be in eden, from-space, or to-space |
duke@435 | 62 | // An object A in eden or from-space may have a copy B |
duke@435 | 63 | // in to-space. If B exists, all roots that once pointed |
duke@435 | 64 | // to A must now point to B. |
duke@435 | 65 | // All objects in the young generation are unmarked. |
duke@435 | 66 | // Eden, from-space, and to-space will all be collected by |
duke@435 | 67 | // the full collection. |
duke@435 | 68 | void handle_promotion_failure(oop); |
duke@435 | 69 | |
duke@435 | 70 | // In the absence of promotion failure, we wouldn't look at "from-space" |
duke@435 | 71 | // objects after a young-gen collection. When promotion fails, however, |
duke@435 | 72 | // the subsequent full collection will look at from-space objects: |
duke@435 | 73 | // therefore we must remove their forwarding pointers. |
duke@435 | 74 | void remove_forwarding_pointers(); |
duke@435 | 75 | |
duke@435 | 76 | // Preserve the mark of "obj", if necessary, in preparation for its mark |
duke@435 | 77 | // word being overwritten with a self-forwarding-pointer. |
duke@435 | 78 | void preserve_mark_if_necessary(oop obj, markOop m); |
duke@435 | 79 | |
duke@435 | 80 | // When one is non-null, so is the other. Together, they each pair is |
duke@435 | 81 | // an object with a preserved mark, and its mark value. |
duke@435 | 82 | GrowableArray<oop>* _objs_with_preserved_marks; |
duke@435 | 83 | GrowableArray<markOop>* _preserved_marks_of_objs; |
duke@435 | 84 | |
duke@435 | 85 | // Returns true if the collection can be safely attempted. |
duke@435 | 86 | // If this method returns false, a collection is not |
duke@435 | 87 | // guaranteed to fail but the system may not be able |
duke@435 | 88 | // to recover from the failure. |
duke@435 | 89 | bool collection_attempt_is_safe(); |
duke@435 | 90 | |
duke@435 | 91 | // Promotion failure handling |
duke@435 | 92 | OopClosure *_promo_failure_scan_stack_closure; |
duke@435 | 93 | void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) { |
duke@435 | 94 | _promo_failure_scan_stack_closure = scan_stack_closure; |
duke@435 | 95 | } |
duke@435 | 96 | |
duke@435 | 97 | GrowableArray<oop>* _promo_failure_scan_stack; |
duke@435 | 98 | GrowableArray<oop>* promo_failure_scan_stack() const { |
duke@435 | 99 | return _promo_failure_scan_stack; |
duke@435 | 100 | } |
duke@435 | 101 | void push_on_promo_failure_scan_stack(oop); |
duke@435 | 102 | void drain_promo_failure_scan_stack(void); |
duke@435 | 103 | bool _promo_failure_drain_in_progress; |
duke@435 | 104 | |
duke@435 | 105 | // Performance Counters |
duke@435 | 106 | GenerationCounters* _gen_counters; |
duke@435 | 107 | CSpaceCounters* _eden_counters; |
duke@435 | 108 | CSpaceCounters* _from_counters; |
duke@435 | 109 | CSpaceCounters* _to_counters; |
duke@435 | 110 | |
duke@435 | 111 | // sizing information |
duke@435 | 112 | size_t _max_eden_size; |
duke@435 | 113 | size_t _max_survivor_size; |
duke@435 | 114 | |
duke@435 | 115 | // Allocation support |
duke@435 | 116 | bool _should_allocate_from_space; |
duke@435 | 117 | bool should_allocate_from_space() const { |
duke@435 | 118 | return _should_allocate_from_space; |
duke@435 | 119 | } |
duke@435 | 120 | void clear_should_allocate_from_space() { |
duke@435 | 121 | _should_allocate_from_space = false; |
duke@435 | 122 | } |
duke@435 | 123 | void set_should_allocate_from_space() { |
duke@435 | 124 | _should_allocate_from_space = true; |
duke@435 | 125 | } |
duke@435 | 126 | |
duke@435 | 127 | protected: |
duke@435 | 128 | // Spaces |
duke@435 | 129 | EdenSpace* _eden_space; |
duke@435 | 130 | ContiguousSpace* _from_space; |
duke@435 | 131 | ContiguousSpace* _to_space; |
duke@435 | 132 | |
duke@435 | 133 | enum SomeProtectedConstants { |
duke@435 | 134 | // Generations are GenGrain-aligned and have size that are multiples of |
duke@435 | 135 | // GenGrain. |
duke@435 | 136 | MinFreeScratchWords = 100 |
duke@435 | 137 | }; |
duke@435 | 138 | |
duke@435 | 139 | // Return the size of a survivor space if this generation were of size |
duke@435 | 140 | // gen_size. |
duke@435 | 141 | size_t compute_survivor_size(size_t gen_size, size_t alignment) const { |
duke@435 | 142 | size_t n = gen_size / (SurvivorRatio + 2); |
duke@435 | 143 | return n > alignment ? align_size_down(n, alignment) : alignment; |
duke@435 | 144 | } |
duke@435 | 145 | |
duke@435 | 146 | public: // was "protected" but caused compile error on win32 |
duke@435 | 147 | class IsAliveClosure: public BoolObjectClosure { |
duke@435 | 148 | Generation* _g; |
duke@435 | 149 | public: |
duke@435 | 150 | IsAliveClosure(Generation* g); |
duke@435 | 151 | void do_object(oop p); |
duke@435 | 152 | bool do_object_b(oop p); |
duke@435 | 153 | }; |
duke@435 | 154 | |
duke@435 | 155 | class KeepAliveClosure: public OopClosure { |
duke@435 | 156 | protected: |
duke@435 | 157 | ScanWeakRefClosure* _cl; |
duke@435 | 158 | CardTableRS* _rs; |
coleenp@548 | 159 | template <class T> void do_oop_work(T* p); |
duke@435 | 160 | public: |
duke@435 | 161 | KeepAliveClosure(ScanWeakRefClosure* cl); |
coleenp@548 | 162 | virtual void do_oop(oop* p); |
coleenp@548 | 163 | virtual void do_oop(narrowOop* p); |
duke@435 | 164 | }; |
duke@435 | 165 | |
duke@435 | 166 | class FastKeepAliveClosure: public KeepAliveClosure { |
duke@435 | 167 | protected: |
duke@435 | 168 | HeapWord* _boundary; |
coleenp@548 | 169 | template <class T> void do_oop_work(T* p); |
duke@435 | 170 | public: |
duke@435 | 171 | FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl); |
coleenp@548 | 172 | virtual void do_oop(oop* p); |
coleenp@548 | 173 | virtual void do_oop(narrowOop* p); |
duke@435 | 174 | }; |
duke@435 | 175 | |
duke@435 | 176 | class EvacuateFollowersClosure: public VoidClosure { |
duke@435 | 177 | GenCollectedHeap* _gch; |
duke@435 | 178 | int _level; |
duke@435 | 179 | ScanClosure* _scan_cur_or_nonheap; |
duke@435 | 180 | ScanClosure* _scan_older; |
duke@435 | 181 | public: |
duke@435 | 182 | EvacuateFollowersClosure(GenCollectedHeap* gch, int level, |
duke@435 | 183 | ScanClosure* cur, ScanClosure* older); |
duke@435 | 184 | void do_void(); |
duke@435 | 185 | }; |
duke@435 | 186 | |
duke@435 | 187 | class FastEvacuateFollowersClosure; |
duke@435 | 188 | friend class FastEvacuateFollowersClosure; |
duke@435 | 189 | class FastEvacuateFollowersClosure: public VoidClosure { |
duke@435 | 190 | GenCollectedHeap* _gch; |
duke@435 | 191 | int _level; |
duke@435 | 192 | DefNewGeneration* _gen; |
duke@435 | 193 | FastScanClosure* _scan_cur_or_nonheap; |
duke@435 | 194 | FastScanClosure* _scan_older; |
duke@435 | 195 | public: |
duke@435 | 196 | FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level, |
duke@435 | 197 | DefNewGeneration* gen, |
duke@435 | 198 | FastScanClosure* cur, |
duke@435 | 199 | FastScanClosure* older); |
duke@435 | 200 | void do_void(); |
duke@435 | 201 | }; |
duke@435 | 202 | |
duke@435 | 203 | public: |
duke@435 | 204 | DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level, |
duke@435 | 205 | const char* policy="Copy"); |
duke@435 | 206 | |
duke@435 | 207 | virtual Generation::Name kind() { return Generation::DefNew; } |
duke@435 | 208 | |
duke@435 | 209 | // Accessing spaces |
duke@435 | 210 | EdenSpace* eden() const { return _eden_space; } |
duke@435 | 211 | ContiguousSpace* from() const { return _from_space; } |
duke@435 | 212 | ContiguousSpace* to() const { return _to_space; } |
duke@435 | 213 | |
coleenp@548 | 214 | virtual CompactibleSpace* first_compaction_space() const; |
duke@435 | 215 | |
duke@435 | 216 | // Space enquiries |
duke@435 | 217 | size_t capacity() const; |
duke@435 | 218 | size_t used() const; |
duke@435 | 219 | size_t free() const; |
duke@435 | 220 | size_t max_capacity() const; |
duke@435 | 221 | size_t capacity_before_gc() const; |
duke@435 | 222 | size_t unsafe_max_alloc_nogc() const; |
duke@435 | 223 | size_t contiguous_available() const; |
duke@435 | 224 | |
duke@435 | 225 | size_t max_eden_size() const { return _max_eden_size; } |
duke@435 | 226 | size_t max_survivor_size() const { return _max_survivor_size; } |
duke@435 | 227 | |
duke@435 | 228 | bool supports_inline_contig_alloc() const { return true; } |
duke@435 | 229 | HeapWord** top_addr() const; |
duke@435 | 230 | HeapWord** end_addr() const; |
duke@435 | 231 | |
duke@435 | 232 | // Thread-local allocation buffers |
duke@435 | 233 | bool supports_tlab_allocation() const { return true; } |
coleenp@548 | 234 | size_t tlab_capacity() const; |
coleenp@548 | 235 | size_t unsafe_max_tlab_alloc() const; |
duke@435 | 236 | |
duke@435 | 237 | // Grow the generation by the specified number of bytes. |
duke@435 | 238 | // The size of bytes is assumed to be properly aligned. |
duke@435 | 239 | // Return true if the expansion was successful. |
duke@435 | 240 | bool expand(size_t bytes); |
duke@435 | 241 | |
duke@435 | 242 | // DefNewGeneration cannot currently expand except at |
duke@435 | 243 | // a GC. |
duke@435 | 244 | virtual bool is_maximal_no_gc() const { return true; } |
duke@435 | 245 | |
duke@435 | 246 | // Iteration |
duke@435 | 247 | void object_iterate(ObjectClosure* blk); |
duke@435 | 248 | void object_iterate_since_last_GC(ObjectClosure* cl); |
duke@435 | 249 | |
duke@435 | 250 | void younger_refs_iterate(OopsInGenClosure* cl); |
duke@435 | 251 | |
duke@435 | 252 | void space_iterate(SpaceClosure* blk, bool usedOnly = false); |
duke@435 | 253 | |
duke@435 | 254 | // Allocation support |
duke@435 | 255 | virtual bool should_allocate(size_t word_size, bool is_tlab) { |
duke@435 | 256 | assert(UseTLAB || !is_tlab, "Should not allocate tlab"); |
duke@435 | 257 | |
duke@435 | 258 | size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); |
duke@435 | 259 | |
duke@435 | 260 | const bool non_zero = word_size > 0; |
duke@435 | 261 | const bool overflows = word_size >= overflow_limit; |
duke@435 | 262 | const bool check_too_big = _pretenure_size_threshold_words > 0; |
duke@435 | 263 | const bool not_too_big = word_size < _pretenure_size_threshold_words; |
duke@435 | 264 | const bool size_ok = is_tlab || !check_too_big || not_too_big; |
duke@435 | 265 | |
duke@435 | 266 | bool result = !overflows && |
duke@435 | 267 | non_zero && |
duke@435 | 268 | size_ok; |
duke@435 | 269 | |
duke@435 | 270 | return result; |
duke@435 | 271 | } |
duke@435 | 272 | |
coleenp@548 | 273 | HeapWord* allocate(size_t word_size, bool is_tlab); |
duke@435 | 274 | HeapWord* allocate_from_space(size_t word_size); |
duke@435 | 275 | |
coleenp@548 | 276 | HeapWord* par_allocate(size_t word_size, bool is_tlab); |
duke@435 | 277 | |
duke@435 | 278 | // Prologue & Epilogue |
coleenp@548 | 279 | virtual void gc_prologue(bool full); |
duke@435 | 280 | virtual void gc_epilogue(bool full); |
duke@435 | 281 | |
jmasa@698 | 282 | // Save the tops for eden, from, and to |
jmasa@698 | 283 | virtual void record_spaces_top(); |
jmasa@698 | 284 | |
duke@435 | 285 | // Doesn't require additional work during GC prologue and epilogue |
duke@435 | 286 | virtual bool performs_in_place_marking() const { return false; } |
duke@435 | 287 | |
duke@435 | 288 | // Accessing marks |
duke@435 | 289 | void save_marks(); |
duke@435 | 290 | void reset_saved_marks(); |
duke@435 | 291 | bool no_allocs_since_save_marks(); |
duke@435 | 292 | |
duke@435 | 293 | // Need to declare the full complement of closures, whether we'll |
duke@435 | 294 | // override them or not, or get message from the compiler: |
duke@435 | 295 | // oop_since_save_marks_iterate_nv hides virtual function... |
duke@435 | 296 | #define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ |
duke@435 | 297 | void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); |
duke@435 | 298 | |
duke@435 | 299 | ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL) |
duke@435 | 300 | |
duke@435 | 301 | #undef DefNew_SINCE_SAVE_MARKS_DECL |
duke@435 | 302 | |
duke@435 | 303 | // For non-youngest collection, the DefNewGeneration can contribute |
duke@435 | 304 | // "to-space". |
jmasa@698 | 305 | virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, |
duke@435 | 306 | size_t max_alloc_words); |
duke@435 | 307 | |
jmasa@698 | 308 | // Reset for contribution of "to-space". |
jmasa@698 | 309 | virtual void reset_scratch(); |
jmasa@698 | 310 | |
duke@435 | 311 | // GC support |
duke@435 | 312 | virtual void compute_new_size(); |
duke@435 | 313 | virtual void collect(bool full, |
duke@435 | 314 | bool clear_all_soft_refs, |
duke@435 | 315 | size_t size, |
duke@435 | 316 | bool is_tlab); |
duke@435 | 317 | HeapWord* expand_and_allocate(size_t size, |
duke@435 | 318 | bool is_tlab, |
duke@435 | 319 | bool parallel = false); |
duke@435 | 320 | |
coleenp@548 | 321 | oop copy_to_survivor_space(oop old); |
duke@435 | 322 | int tenuring_threshold() { return _tenuring_threshold; } |
duke@435 | 323 | |
duke@435 | 324 | // Performance Counter support |
duke@435 | 325 | void update_counters(); |
duke@435 | 326 | |
duke@435 | 327 | // Printing |
duke@435 | 328 | virtual const char* name() const; |
duke@435 | 329 | virtual const char* short_name() const { return "DefNew"; } |
duke@435 | 330 | |
duke@435 | 331 | bool must_be_youngest() const { return true; } |
duke@435 | 332 | bool must_be_oldest() const { return false; } |
duke@435 | 333 | |
duke@435 | 334 | // PrintHeapAtGC support. |
duke@435 | 335 | void print_on(outputStream* st) const; |
duke@435 | 336 | |
duke@435 | 337 | void verify(bool allow_dirty); |
duke@435 | 338 | |
duke@435 | 339 | protected: |
jmasa@698 | 340 | // If clear_space is true, clear the survivor spaces. Eden is |
jmasa@698 | 341 | // cleared if the minimum size of eden is 0. If mangle_space |
jmasa@698 | 342 | // is true, also mangle the space in debug mode. |
jmasa@698 | 343 | void compute_space_boundaries(uintx minimum_eden_size, |
jmasa@698 | 344 | bool clear_space, |
jmasa@698 | 345 | bool mangle_space); |
duke@435 | 346 | // Scavenge support |
duke@435 | 347 | void swap_spaces(); |
duke@435 | 348 | }; |