1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/defNewGeneration.hpp Sat Dec 01 00:00:00 2007 +0000
1.3 @@ -0,0 +1,332 @@
1.4 +/*
1.5 + * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
1.23 + * CA 95054 USA or visit www.sun.com if you need additional information or
1.24 + * have any questions.
1.25 + *
1.26 + */
1.27 +
1.28 +class EdenSpace;
1.29 +class ContiguousSpace;
1.30 +
1.31 +// DefNewGeneration is a young generation containing eden, from- and
1.32 +// to-space.
1.33 +
1.34 +class DefNewGeneration: public Generation {
1.35 + friend class VMStructs;
1.36 +
1.37 +protected:
1.38 + Generation* _next_gen;
1.39 + int _tenuring_threshold; // Tenuring threshold for next collection.
1.40 + ageTable _age_table;
1.41 + // Size of object to pretenure in words; command line provides bytes
1.42 + size_t _pretenure_size_threshold_words;
1.43 +
1.44 + ageTable* age_table() { return &_age_table; }
1.45 + // Initialize state to optimistically assume no promotion failure will
1.46 + // happen.
1.47 + void init_assuming_no_promotion_failure();
1.48 + // True iff a promotion has failed in the current collection.
1.49 + bool _promotion_failed;
1.50 + bool promotion_failed() { return _promotion_failed; }
1.51 +
1.52 + // Handling promotion failure. A young generation collection
1.53 + // can fail if a live object cannot be copied out of its
1.54 + // location in eden or from-space during the collection. If
1.55 + // a collection fails, the young generation is left in a
1.56 + // consistent state such that it can be collected by a
1.57 + // full collection.
1.58 + // Before the collection
1.59 + // Objects are in eden or from-space
1.60 + // All roots into the young generation point into eden or from-space.
1.61 + //
1.62 + // After a failed collection
1.63 + // Objects may be in eden, from-space, or to-space
1.64 + // An object A in eden or from-space may have a copy B
1.65 + // in to-space. If B exists, all roots that once pointed
1.66 + // to A must now point to B.
1.67 + // All objects in the young generation are unmarked.
1.68 + // Eden, from-space, and to-space will all be collected by
1.69 + // the full collection.
1.70 + void handle_promotion_failure(oop);
1.71 +
1.72 + // In the absence of promotion failure, we wouldn't look at "from-space"
1.73 + // objects after a young-gen collection. When promotion fails, however,
1.74 + // the subsequent full collection will look at from-space objects:
1.75 + // therefore we must remove their forwarding pointers.
1.76 + void remove_forwarding_pointers();
1.77 +
1.78 + // Preserve the mark of "obj", if necessary, in preparation for its mark
1.79 + // word being overwritten with a self-forwarding-pointer.
1.80 + void preserve_mark_if_necessary(oop obj, markOop m);
1.81 +
1.82 + // When one is non-null, so is the other. Together, they each pair is
1.83 + // an object with a preserved mark, and its mark value.
1.84 + GrowableArray<oop>* _objs_with_preserved_marks;
1.85 + GrowableArray<markOop>* _preserved_marks_of_objs;
1.86 +
1.87 + // Returns true if the collection can be safely attempted.
1.88 + // If this method returns false, a collection is not
1.89 + // guaranteed to fail but the system may not be able
1.90 + // to recover from the failure.
1.91 + bool collection_attempt_is_safe();
1.92 +
1.93 + // Promotion failure handling
1.94 + OopClosure *_promo_failure_scan_stack_closure;
1.95 + void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) {
1.96 + _promo_failure_scan_stack_closure = scan_stack_closure;
1.97 + }
1.98 +
1.99 + GrowableArray<oop>* _promo_failure_scan_stack;
1.100 + GrowableArray<oop>* promo_failure_scan_stack() const {
1.101 + return _promo_failure_scan_stack;
1.102 + }
1.103 + void push_on_promo_failure_scan_stack(oop);
1.104 + void drain_promo_failure_scan_stack(void);
1.105 + bool _promo_failure_drain_in_progress;
1.106 +
1.107 + // Performance Counters
1.108 + GenerationCounters* _gen_counters;
1.109 + CSpaceCounters* _eden_counters;
1.110 + CSpaceCounters* _from_counters;
1.111 + CSpaceCounters* _to_counters;
1.112 +
1.113 + // sizing information
1.114 + size_t _max_eden_size;
1.115 + size_t _max_survivor_size;
1.116 +
1.117 + // Allocation support
1.118 + bool _should_allocate_from_space;
1.119 + bool should_allocate_from_space() const {
1.120 + return _should_allocate_from_space;
1.121 + }
1.122 + void clear_should_allocate_from_space() {
1.123 + _should_allocate_from_space = false;
1.124 + }
1.125 + void set_should_allocate_from_space() {
1.126 + _should_allocate_from_space = true;
1.127 + }
1.128 +
1.129 + protected:
1.130 + // Spaces
1.131 + EdenSpace* _eden_space;
1.132 + ContiguousSpace* _from_space;
1.133 + ContiguousSpace* _to_space;
1.134 +
1.135 + enum SomeProtectedConstants {
1.136 + // Generations are GenGrain-aligned and have size that are multiples of
1.137 + // GenGrain.
1.138 + MinFreeScratchWords = 100
1.139 + };
1.140 +
1.141 + // Return the size of a survivor space if this generation were of size
1.142 + // gen_size.
1.143 + size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
1.144 + size_t n = gen_size / (SurvivorRatio + 2);
1.145 + return n > alignment ? align_size_down(n, alignment) : alignment;
1.146 + }
1.147 +
1.148 + public: // was "protected" but caused compile error on win32
1.149 + class IsAliveClosure: public BoolObjectClosure {
1.150 + Generation* _g;
1.151 + public:
1.152 + IsAliveClosure(Generation* g);
1.153 + void do_object(oop p);
1.154 + bool do_object_b(oop p);
1.155 + };
1.156 +
1.157 + class KeepAliveClosure: public OopClosure {
1.158 + protected:
1.159 + ScanWeakRefClosure* _cl;
1.160 + CardTableRS* _rs;
1.161 + public:
1.162 + KeepAliveClosure(ScanWeakRefClosure* cl);
1.163 + void do_oop(oop* p);
1.164 + };
1.165 +
1.166 + class FastKeepAliveClosure: public KeepAliveClosure {
1.167 + protected:
1.168 + HeapWord* _boundary;
1.169 + public:
1.170 + FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
1.171 + void do_oop(oop* p);
1.172 + };
1.173 +
1.174 + class EvacuateFollowersClosure: public VoidClosure {
1.175 + GenCollectedHeap* _gch;
1.176 + int _level;
1.177 + ScanClosure* _scan_cur_or_nonheap;
1.178 + ScanClosure* _scan_older;
1.179 + public:
1.180 + EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
1.181 + ScanClosure* cur, ScanClosure* older);
1.182 + void do_void();
1.183 + };
1.184 +
1.185 + class FastEvacuateFollowersClosure;
1.186 + friend class FastEvacuateFollowersClosure;
1.187 + class FastEvacuateFollowersClosure: public VoidClosure {
1.188 + GenCollectedHeap* _gch;
1.189 + int _level;
1.190 + DefNewGeneration* _gen;
1.191 + FastScanClosure* _scan_cur_or_nonheap;
1.192 + FastScanClosure* _scan_older;
1.193 + public:
1.194 + FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
1.195 + DefNewGeneration* gen,
1.196 + FastScanClosure* cur,
1.197 + FastScanClosure* older);
1.198 + void do_void();
1.199 + };
1.200 +
1.201 + public:
1.202 + DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
1.203 + const char* policy="Copy");
1.204 +
1.205 + virtual Generation::Name kind() { return Generation::DefNew; }
1.206 +
1.207 + // Accessing spaces
1.208 + EdenSpace* eden() const { return _eden_space; }
1.209 + ContiguousSpace* from() const { return _from_space; }
1.210 + ContiguousSpace* to() const { return _to_space; }
1.211 +
1.212 + inline CompactibleSpace* first_compaction_space() const;
1.213 +
1.214 + // Space enquiries
1.215 + size_t capacity() const;
1.216 + size_t used() const;
1.217 + size_t free() const;
1.218 + size_t max_capacity() const;
1.219 + size_t capacity_before_gc() const;
1.220 + size_t unsafe_max_alloc_nogc() const;
1.221 + size_t contiguous_available() const;
1.222 +
1.223 + size_t max_eden_size() const { return _max_eden_size; }
1.224 + size_t max_survivor_size() const { return _max_survivor_size; }
1.225 +
1.226 + bool supports_inline_contig_alloc() const { return true; }
1.227 + HeapWord** top_addr() const;
1.228 + HeapWord** end_addr() const;
1.229 +
1.230 + // Thread-local allocation buffers
1.231 + bool supports_tlab_allocation() const { return true; }
1.232 + inline size_t tlab_capacity() const;
1.233 + inline size_t unsafe_max_tlab_alloc() const;
1.234 +
1.235 + // Grow the generation by the specified number of bytes.
1.236 + // The size of bytes is assumed to be properly aligned.
1.237 + // Return true if the expansion was successful.
1.238 + bool expand(size_t bytes);
1.239 +
1.240 + // DefNewGeneration cannot currently expand except at
1.241 + // a GC.
1.242 + virtual bool is_maximal_no_gc() const { return true; }
1.243 +
1.244 + // Iteration
1.245 + void object_iterate(ObjectClosure* blk);
1.246 + void object_iterate_since_last_GC(ObjectClosure* cl);
1.247 +
1.248 + void younger_refs_iterate(OopsInGenClosure* cl);
1.249 +
1.250 + void space_iterate(SpaceClosure* blk, bool usedOnly = false);
1.251 +
1.252 + // Allocation support
1.253 + virtual bool should_allocate(size_t word_size, bool is_tlab) {
1.254 + assert(UseTLAB || !is_tlab, "Should not allocate tlab");
1.255 +
1.256 + size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
1.257 +
1.258 + const bool non_zero = word_size > 0;
1.259 + const bool overflows = word_size >= overflow_limit;
1.260 + const bool check_too_big = _pretenure_size_threshold_words > 0;
1.261 + const bool not_too_big = word_size < _pretenure_size_threshold_words;
1.262 + const bool size_ok = is_tlab || !check_too_big || not_too_big;
1.263 +
1.264 + bool result = !overflows &&
1.265 + non_zero &&
1.266 + size_ok;
1.267 +
1.268 + return result;
1.269 + }
1.270 +
1.271 + inline HeapWord* allocate(size_t word_size, bool is_tlab);
1.272 + HeapWord* allocate_from_space(size_t word_size);
1.273 +
1.274 + inline HeapWord* par_allocate(size_t word_size, bool is_tlab);
1.275 +
1.276 + // Prologue & Epilogue
1.277 + inline virtual void gc_prologue(bool full);
1.278 + virtual void gc_epilogue(bool full);
1.279 +
1.280 + // Doesn't require additional work during GC prologue and epilogue
1.281 + virtual bool performs_in_place_marking() const { return false; }
1.282 +
1.283 + // Accessing marks
1.284 + void save_marks();
1.285 + void reset_saved_marks();
1.286 + bool no_allocs_since_save_marks();
1.287 +
1.288 + // Need to declare the full complement of closures, whether we'll
1.289 + // override them or not, or get message from the compiler:
1.290 + // oop_since_save_marks_iterate_nv hides virtual function...
1.291 +#define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
1.292 + void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
1.293 +
1.294 + ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
1.295 +
1.296 +#undef DefNew_SINCE_SAVE_MARKS_DECL
1.297 +
1.298 + // For non-youngest collection, the DefNewGeneration can contribute
1.299 + // "to-space".
1.300 + void contribute_scratch(ScratchBlock*& list, Generation* requestor,
1.301 + size_t max_alloc_words);
1.302 +
1.303 + // GC support
1.304 + virtual void compute_new_size();
1.305 + virtual void collect(bool full,
1.306 + bool clear_all_soft_refs,
1.307 + size_t size,
1.308 + bool is_tlab);
1.309 + HeapWord* expand_and_allocate(size_t size,
1.310 + bool is_tlab,
1.311 + bool parallel = false);
1.312 +
1.313 + oop copy_to_survivor_space(oop old, oop* from);
1.314 + int tenuring_threshold() { return _tenuring_threshold; }
1.315 +
1.316 + // Performance Counter support
1.317 + void update_counters();
1.318 +
1.319 + // Printing
1.320 + virtual const char* name() const;
1.321 + virtual const char* short_name() const { return "DefNew"; }
1.322 +
1.323 + bool must_be_youngest() const { return true; }
1.324 + bool must_be_oldest() const { return false; }
1.325 +
1.326 + // PrintHeapAtGC support.
1.327 + void print_on(outputStream* st) const;
1.328 +
1.329 + void verify(bool allow_dirty);
1.330 +
1.331 + protected:
1.332 + void compute_space_boundaries(uintx minimum_eden_size);
1.333 + // Scavenge support
1.334 + void swap_spaces();
1.335 +};
