Mon, 29 Apr 2013 16:13:57 -0400
8011773: Some tests on Interned String crashed JVM with OOM
Summary: Instead of terminating the VM, throw OutOfMemoryError exceptions.
Reviewed-by: coleenp, dholmes
1 /*
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25 #ifndef SHARE_VM_MEMORY_DEFNEWGENERATION_HPP
26 #define SHARE_VM_MEMORY_DEFNEWGENERATION_HPP
28 #include "gc_implementation/shared/ageTable.hpp"
29 #include "gc_implementation/shared/cSpaceCounters.hpp"
30 #include "gc_implementation/shared/generationCounters.hpp"
31 #include "memory/generation.inline.hpp"
32 #include "utilities/stack.hpp"
34 class EdenSpace;
35 class ContiguousSpace;
36 class ScanClosure;
38 // DefNewGeneration is a young generation containing eden, from- and
39 // to-space.
41 class DefNewGeneration: public Generation {
42 friend class VMStructs;
44 protected:
45 Generation* _next_gen;
46 uint _tenuring_threshold; // Tenuring threshold for next collection.
47 ageTable _age_table;
48 // Size of object to pretenure in words; command line provides bytes
49 size_t _pretenure_size_threshold_words;
51 ageTable* age_table() { return &_age_table; }
52 // Initialize state to optimistically assume no promotion failure will
53 // happen.
54 void init_assuming_no_promotion_failure();
55 // True iff a promotion has failed in the current collection.
56 bool _promotion_failed;
57 bool promotion_failed() { return _promotion_failed; }
59 // Handling promotion failure. A young generation collection
60 // can fail if a live object cannot be copied out of its
61 // location in eden or from-space during the collection. If
62 // a collection fails, the young generation is left in a
63 // consistent state such that it can be collected by a
64 // full collection.
65 // Before the collection
66 // Objects are in eden or from-space
67 // All roots into the young generation point into eden or from-space.
68 //
69 // After a failed collection
70 // Objects may be in eden, from-space, or to-space
71 // An object A in eden or from-space may have a copy B
72 // in to-space. If B exists, all roots that once pointed
73 // to A must now point to B.
74 // All objects in the young generation are unmarked.
75 // Eden, from-space, and to-space will all be collected by
76 // the full collection.
77 void handle_promotion_failure(oop);
79 // In the absence of promotion failure, we wouldn't look at "from-space"
80 // objects after a young-gen collection. When promotion fails, however,
81 // the subsequent full collection will look at from-space objects:
82 // therefore we must remove their forwarding pointers.
83 void remove_forwarding_pointers();
85 // Preserve the mark of "obj", if necessary, in preparation for its mark
86 // word being overwritten with a self-forwarding-pointer.
87 void preserve_mark_if_necessary(oop obj, markOop m);
88 void preserve_mark(oop obj, markOop m); // work routine used by the above
90 // Together, these keep <object with a preserved mark, mark value> pairs.
91 // They should always contain the same number of elements.
92 Stack<oop, mtGC> _objs_with_preserved_marks;
93 Stack<markOop, mtGC> _preserved_marks_of_objs;
95 // Promotion failure handling
96 ExtendedOopClosure *_promo_failure_scan_stack_closure;
97 void set_promo_failure_scan_stack_closure(ExtendedOopClosure *scan_stack_closure) {
98 _promo_failure_scan_stack_closure = scan_stack_closure;
99 }
101 Stack<oop, mtGC> _promo_failure_scan_stack;
102 void drain_promo_failure_scan_stack(void);
103 bool _promo_failure_drain_in_progress;
105 // Performance Counters
106 GenerationCounters* _gen_counters;
107 CSpaceCounters* _eden_counters;
108 CSpaceCounters* _from_counters;
109 CSpaceCounters* _to_counters;
111 // sizing information
112 size_t _max_eden_size;
113 size_t _max_survivor_size;
115 // Allocation support
116 bool _should_allocate_from_space;
117 bool should_allocate_from_space() const {
118 return _should_allocate_from_space;
119 }
120 void clear_should_allocate_from_space() {
121 _should_allocate_from_space = false;
122 }
123 void set_should_allocate_from_space() {
124 _should_allocate_from_space = true;
125 }
127 // Tenuring
128 void adjust_desired_tenuring_threshold();
130 // Spaces
131 EdenSpace* _eden_space;
132 ContiguousSpace* _from_space;
133 ContiguousSpace* _to_space;
135 enum SomeProtectedConstants {
136 // Generations are GenGrain-aligned and have size that are multiples of
137 // GenGrain.
138 MinFreeScratchWords = 100
139 };
141 // Return the size of a survivor space if this generation were of size
142 // gen_size.
143 size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
144 size_t n = gen_size / (SurvivorRatio + 2);
145 return n > alignment ? align_size_down(n, alignment) : alignment;
146 }
148 public: // was "protected" but caused compile error on win32
149 class IsAliveClosure: public BoolObjectClosure {
150 Generation* _g;
151 public:
152 IsAliveClosure(Generation* g);
153 void do_object(oop p);
154 bool do_object_b(oop p);
155 };
157 class KeepAliveClosure: public OopClosure {
158 protected:
159 ScanWeakRefClosure* _cl;
160 CardTableRS* _rs;
161 template <class T> void do_oop_work(T* p);
162 public:
163 KeepAliveClosure(ScanWeakRefClosure* cl);
164 virtual void do_oop(oop* p);
165 virtual void do_oop(narrowOop* p);
166 };
168 class FastKeepAliveClosure: public KeepAliveClosure {
169 protected:
170 HeapWord* _boundary;
171 template <class T> void do_oop_work(T* p);
172 public:
173 FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
174 virtual void do_oop(oop* p);
175 virtual void do_oop(narrowOop* p);
176 };
178 class EvacuateFollowersClosure: public VoidClosure {
179 GenCollectedHeap* _gch;
180 int _level;
181 ScanClosure* _scan_cur_or_nonheap;
182 ScanClosure* _scan_older;
183 public:
184 EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
185 ScanClosure* cur, ScanClosure* older);
186 void do_void();
187 };
189 class FastEvacuateFollowersClosure: public VoidClosure {
190 GenCollectedHeap* _gch;
191 int _level;
192 DefNewGeneration* _gen;
193 FastScanClosure* _scan_cur_or_nonheap;
194 FastScanClosure* _scan_older;
195 public:
196 FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
197 DefNewGeneration* gen,
198 FastScanClosure* cur,
199 FastScanClosure* older);
200 void do_void();
201 };
203 public:
204 DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
205 const char* policy="Copy");
207 virtual Generation::Name kind() { return Generation::DefNew; }
209 // Accessing spaces
210 EdenSpace* eden() const { return _eden_space; }
211 ContiguousSpace* from() const { return _from_space; }
212 ContiguousSpace* to() const { return _to_space; }
214 virtual CompactibleSpace* first_compaction_space() const;
216 // Space enquiries
217 size_t capacity() const;
218 size_t used() const;
219 size_t free() const;
220 size_t max_capacity() const;
221 size_t capacity_before_gc() const;
222 size_t unsafe_max_alloc_nogc() const;
223 size_t contiguous_available() const;
225 size_t max_eden_size() const { return _max_eden_size; }
226 size_t max_survivor_size() const { return _max_survivor_size; }
228 bool supports_inline_contig_alloc() const { return true; }
229 HeapWord** top_addr() const;
230 HeapWord** end_addr() const;
232 // Thread-local allocation buffers
233 bool supports_tlab_allocation() const { return true; }
234 size_t tlab_capacity() const;
235 size_t unsafe_max_tlab_alloc() const;
237 // Grow the generation by the specified number of bytes.
238 // The size of bytes is assumed to be properly aligned.
239 // Return true if the expansion was successful.
240 bool expand(size_t bytes);
242 // DefNewGeneration cannot currently expand except at
243 // a GC.
244 virtual bool is_maximal_no_gc() const { return true; }
246 // Iteration
247 void object_iterate(ObjectClosure* blk);
248 void object_iterate_since_last_GC(ObjectClosure* cl);
250 void younger_refs_iterate(OopsInGenClosure* cl);
252 void space_iterate(SpaceClosure* blk, bool usedOnly = false);
254 // Allocation support
255 virtual bool should_allocate(size_t word_size, bool is_tlab) {
256 assert(UseTLAB || !is_tlab, "Should not allocate tlab");
258 size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
260 const bool non_zero = word_size > 0;
261 const bool overflows = word_size >= overflow_limit;
262 const bool check_too_big = _pretenure_size_threshold_words > 0;
263 const bool not_too_big = word_size < _pretenure_size_threshold_words;
264 const bool size_ok = is_tlab || !check_too_big || not_too_big;
266 bool result = !overflows &&
267 non_zero &&
268 size_ok;
270 return result;
271 }
273 HeapWord* allocate(size_t word_size, bool is_tlab);
274 HeapWord* allocate_from_space(size_t word_size);
276 HeapWord* par_allocate(size_t word_size, bool is_tlab);
278 // Prologue & Epilogue
279 virtual void gc_prologue(bool full);
280 virtual void gc_epilogue(bool full);
282 // Save the tops for eden, from, and to
283 virtual void record_spaces_top();
285 // Doesn't require additional work during GC prologue and epilogue
286 virtual bool performs_in_place_marking() const { return false; }
288 // Accessing marks
289 void save_marks();
290 void reset_saved_marks();
291 bool no_allocs_since_save_marks();
293 // Need to declare the full complement of closures, whether we'll
294 // override them or not, or get message from the compiler:
295 // oop_since_save_marks_iterate_nv hides virtual function...
296 #define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
297 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
299 ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
301 #undef DefNew_SINCE_SAVE_MARKS_DECL
303 // For non-youngest collection, the DefNewGeneration can contribute
304 // "to-space".
305 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor,
306 size_t max_alloc_words);
308 // Reset for contribution of "to-space".
309 virtual void reset_scratch();
311 // GC support
312 virtual void compute_new_size();
314 // Returns true if the collection is likely to be safely
315 // completed. Even if this method returns true, a collection
316 // may not be guaranteed to succeed, and the system should be
317 // able to safely unwind and recover from that failure, albeit
318 // at some additional cost. Override superclass's implementation.
319 virtual bool collection_attempt_is_safe();
321 virtual void collect(bool full,
322 bool clear_all_soft_refs,
323 size_t size,
324 bool is_tlab);
325 HeapWord* expand_and_allocate(size_t size,
326 bool is_tlab,
327 bool parallel = false);
329 oop copy_to_survivor_space(oop old);
330 uint tenuring_threshold() { return _tenuring_threshold; }
332 // Performance Counter support
333 void update_counters();
335 // Printing
336 virtual const char* name() const;
337 virtual const char* short_name() const { return "DefNew"; }
339 bool must_be_youngest() const { return true; }
340 bool must_be_oldest() const { return false; }
342 // PrintHeapAtGC support.
343 void print_on(outputStream* st) const;
345 void verify();
347 bool promo_failure_scan_is_complete() const {
348 return _promo_failure_scan_stack.is_empty();
349 }
351 protected:
352 // If clear_space is true, clear the survivor spaces. Eden is
353 // cleared if the minimum size of eden is 0. If mangle_space
354 // is true, also mangle the space in debug mode.
355 void compute_space_boundaries(uintx minimum_eden_size,
356 bool clear_space,
357 bool mangle_space);
358 // Scavenge support
359 void swap_spaces();
360 };
362 #endif // SHARE_VM_MEMORY_DEFNEWGENERATION_HPP