Wed, 11 Sep 2013 00:38:18 -0400
8024256: Minimal VM build is broken with PCH disabled
Reviewed-by: coleenp, twisti
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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
8 *
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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).
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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,
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23 */
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 "gc_implementation/shared/copyFailedInfo.hpp"
32 #include "memory/generation.inline.hpp"
33 #include "utilities/stack.hpp"
35 class EdenSpace;
36 class ContiguousSpace;
37 class ScanClosure;
38 class STWGCTimer;
40 // DefNewGeneration is a young generation containing eden, from- and
41 // to-space.
43 class DefNewGeneration: public Generation {
44 friend class VMStructs;
46 protected:
47 Generation* _next_gen;
48 uint _tenuring_threshold; // Tenuring threshold for next collection.
49 ageTable _age_table;
50 // Size of object to pretenure in words; command line provides bytes
51 size_t _pretenure_size_threshold_words;
53 ageTable* age_table() { return &_age_table; }
55 // Initialize state to optimistically assume no promotion failure will
56 // happen.
57 void init_assuming_no_promotion_failure();
58 // True iff a promotion has failed in the current collection.
59 bool _promotion_failed;
60 bool promotion_failed() { return _promotion_failed; }
61 PromotionFailedInfo _promotion_failed_info;
63 // Handling promotion failure. A young generation collection
64 // can fail if a live object cannot be copied out of its
65 // location in eden or from-space during the collection. If
66 // a collection fails, the young generation is left in a
67 // consistent state such that it can be collected by a
68 // full collection.
69 // Before the collection
70 // Objects are in eden or from-space
71 // All roots into the young generation point into eden or from-space.
72 //
73 // After a failed collection
74 // Objects may be in eden, from-space, or to-space
75 // An object A in eden or from-space may have a copy B
76 // in to-space. If B exists, all roots that once pointed
77 // to A must now point to B.
78 // All objects in the young generation are unmarked.
79 // Eden, from-space, and to-space will all be collected by
80 // the full collection.
81 void handle_promotion_failure(oop);
83 // In the absence of promotion failure, we wouldn't look at "from-space"
84 // objects after a young-gen collection. When promotion fails, however,
85 // the subsequent full collection will look at from-space objects:
86 // therefore we must remove their forwarding pointers.
87 void remove_forwarding_pointers();
89 // Preserve the mark of "obj", if necessary, in preparation for its mark
90 // word being overwritten with a self-forwarding-pointer.
91 void preserve_mark_if_necessary(oop obj, markOop m);
92 void preserve_mark(oop obj, markOop m); // work routine used by the above
94 // Together, these keep <object with a preserved mark, mark value> pairs.
95 // They should always contain the same number of elements.
96 Stack<oop, mtGC> _objs_with_preserved_marks;
97 Stack<markOop, mtGC> _preserved_marks_of_objs;
99 // Promotion failure handling
100 ExtendedOopClosure *_promo_failure_scan_stack_closure;
101 void set_promo_failure_scan_stack_closure(ExtendedOopClosure *scan_stack_closure) {
102 _promo_failure_scan_stack_closure = scan_stack_closure;
103 }
105 Stack<oop, mtGC> _promo_failure_scan_stack;
106 void drain_promo_failure_scan_stack(void);
107 bool _promo_failure_drain_in_progress;
109 // Performance Counters
110 GenerationCounters* _gen_counters;
111 CSpaceCounters* _eden_counters;
112 CSpaceCounters* _from_counters;
113 CSpaceCounters* _to_counters;
115 // sizing information
116 size_t _max_eden_size;
117 size_t _max_survivor_size;
119 // Allocation support
120 bool _should_allocate_from_space;
121 bool should_allocate_from_space() const {
122 return _should_allocate_from_space;
123 }
124 void clear_should_allocate_from_space() {
125 _should_allocate_from_space = false;
126 }
127 void set_should_allocate_from_space() {
128 _should_allocate_from_space = true;
129 }
131 // Tenuring
132 void adjust_desired_tenuring_threshold();
134 // Spaces
135 EdenSpace* _eden_space;
136 ContiguousSpace* _from_space;
137 ContiguousSpace* _to_space;
139 STWGCTimer* _gc_timer;
141 enum SomeProtectedConstants {
142 // Generations are GenGrain-aligned and have size that are multiples of
143 // GenGrain.
144 MinFreeScratchWords = 100
145 };
147 // Return the size of a survivor space if this generation were of size
148 // gen_size.
149 size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
150 size_t n = gen_size / (SurvivorRatio + 2);
151 return n > alignment ? align_size_down(n, alignment) : alignment;
152 }
154 public: // was "protected" but caused compile error on win32
155 class IsAliveClosure: public BoolObjectClosure {
156 Generation* _g;
157 public:
158 IsAliveClosure(Generation* g);
159 bool do_object_b(oop p);
160 };
162 class KeepAliveClosure: public OopClosure {
163 protected:
164 ScanWeakRefClosure* _cl;
165 CardTableRS* _rs;
166 template <class T> void do_oop_work(T* p);
167 public:
168 KeepAliveClosure(ScanWeakRefClosure* cl);
169 virtual void do_oop(oop* p);
170 virtual void do_oop(narrowOop* p);
171 };
173 class FastKeepAliveClosure: public KeepAliveClosure {
174 protected:
175 HeapWord* _boundary;
176 template <class T> void do_oop_work(T* p);
177 public:
178 FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
179 virtual void do_oop(oop* p);
180 virtual void do_oop(narrowOop* p);
181 };
183 class EvacuateFollowersClosure: public VoidClosure {
184 GenCollectedHeap* _gch;
185 int _level;
186 ScanClosure* _scan_cur_or_nonheap;
187 ScanClosure* _scan_older;
188 public:
189 EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
190 ScanClosure* cur, ScanClosure* older);
191 void do_void();
192 };
194 class FastEvacuateFollowersClosure: public VoidClosure {
195 GenCollectedHeap* _gch;
196 int _level;
197 DefNewGeneration* _gen;
198 FastScanClosure* _scan_cur_or_nonheap;
199 FastScanClosure* _scan_older;
200 public:
201 FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
202 DefNewGeneration* gen,
203 FastScanClosure* cur,
204 FastScanClosure* older);
205 void do_void();
206 };
208 public:
209 DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
210 const char* policy="Copy");
212 virtual void ref_processor_init();
214 virtual Generation::Name kind() { return Generation::DefNew; }
216 // Accessing spaces
217 EdenSpace* eden() const { return _eden_space; }
218 ContiguousSpace* from() const { return _from_space; }
219 ContiguousSpace* to() const { return _to_space; }
221 virtual CompactibleSpace* first_compaction_space() const;
223 // Space enquiries
224 size_t capacity() const;
225 size_t used() const;
226 size_t free() const;
227 size_t max_capacity() const;
228 size_t capacity_before_gc() const;
229 size_t unsafe_max_alloc_nogc() const;
230 size_t contiguous_available() const;
232 size_t max_eden_size() const { return _max_eden_size; }
233 size_t max_survivor_size() const { return _max_survivor_size; }
235 bool supports_inline_contig_alloc() const { return true; }
236 HeapWord** top_addr() const;
237 HeapWord** end_addr() const;
239 // Thread-local allocation buffers
240 bool supports_tlab_allocation() const { return true; }
241 size_t tlab_capacity() const;
242 size_t unsafe_max_tlab_alloc() const;
244 // Grow the generation by the specified number of bytes.
245 // The size of bytes is assumed to be properly aligned.
246 // Return true if the expansion was successful.
247 bool expand(size_t bytes);
249 // DefNewGeneration cannot currently expand except at
250 // a GC.
251 virtual bool is_maximal_no_gc() const { return true; }
253 // Iteration
254 void object_iterate(ObjectClosure* blk);
256 void younger_refs_iterate(OopsInGenClosure* cl);
258 void space_iterate(SpaceClosure* blk, bool usedOnly = false);
260 // Allocation support
261 virtual bool should_allocate(size_t word_size, bool is_tlab) {
262 assert(UseTLAB || !is_tlab, "Should not allocate tlab");
264 size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
266 const bool non_zero = word_size > 0;
267 const bool overflows = word_size >= overflow_limit;
268 const bool check_too_big = _pretenure_size_threshold_words > 0;
269 const bool not_too_big = word_size < _pretenure_size_threshold_words;
270 const bool size_ok = is_tlab || !check_too_big || not_too_big;
272 bool result = !overflows &&
273 non_zero &&
274 size_ok;
276 return result;
277 }
279 HeapWord* allocate(size_t word_size, bool is_tlab);
280 HeapWord* allocate_from_space(size_t word_size);
282 HeapWord* par_allocate(size_t word_size, bool is_tlab);
284 // Prologue & Epilogue
285 virtual void gc_prologue(bool full);
286 virtual void gc_epilogue(bool full);
288 // Save the tops for eden, from, and to
289 virtual void record_spaces_top();
291 // Doesn't require additional work during GC prologue and epilogue
292 virtual bool performs_in_place_marking() const { return false; }
294 // Accessing marks
295 void save_marks();
296 void reset_saved_marks();
297 bool no_allocs_since_save_marks();
299 // Need to declare the full complement of closures, whether we'll
300 // override them or not, or get message from the compiler:
301 // oop_since_save_marks_iterate_nv hides virtual function...
302 #define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
303 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
305 ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
307 #undef DefNew_SINCE_SAVE_MARKS_DECL
309 // For non-youngest collection, the DefNewGeneration can contribute
310 // "to-space".
311 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor,
312 size_t max_alloc_words);
314 // Reset for contribution of "to-space".
315 virtual void reset_scratch();
317 // GC support
318 virtual void compute_new_size();
320 // Returns true if the collection is likely to be safely
321 // completed. Even if this method returns true, a collection
322 // may not be guaranteed to succeed, and the system should be
323 // able to safely unwind and recover from that failure, albeit
324 // at some additional cost. Override superclass's implementation.
325 virtual bool collection_attempt_is_safe();
327 virtual void collect(bool full,
328 bool clear_all_soft_refs,
329 size_t size,
330 bool is_tlab);
331 HeapWord* expand_and_allocate(size_t size,
332 bool is_tlab,
333 bool parallel = false);
335 oop copy_to_survivor_space(oop old);
336 uint tenuring_threshold() { return _tenuring_threshold; }
338 // Performance Counter support
339 void update_counters();
341 // Printing
342 virtual const char* name() const;
343 virtual const char* short_name() const { return "DefNew"; }
345 bool must_be_youngest() const { return true; }
346 bool must_be_oldest() const { return false; }
348 // PrintHeapAtGC support.
349 void print_on(outputStream* st) const;
351 void verify();
353 bool promo_failure_scan_is_complete() const {
354 return _promo_failure_scan_stack.is_empty();
355 }
357 protected:
358 // If clear_space is true, clear the survivor spaces. Eden is
359 // cleared if the minimum size of eden is 0. If mangle_space
360 // is true, also mangle the space in debug mode.
361 void compute_space_boundaries(uintx minimum_eden_size,
362 bool clear_space,
363 bool mangle_space);
364 // Scavenge support
365 void swap_spaces();
366 };
368 #endif // SHARE_VM_MEMORY_DEFNEWGENERATION_HPP