1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/defNewGeneration.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,369 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2013, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_MEMORY_DEFNEWGENERATION_HPP
1.29 +#define SHARE_VM_MEMORY_DEFNEWGENERATION_HPP
1.30 +
1.31 +#include "gc_implementation/shared/ageTable.hpp"
1.32 +#include "gc_implementation/shared/cSpaceCounters.hpp"
1.33 +#include "gc_implementation/shared/generationCounters.hpp"
1.34 +#include "gc_implementation/shared/copyFailedInfo.hpp"
1.35 +#include "memory/generation.inline.hpp"
1.36 +#include "utilities/stack.hpp"
1.37 +
1.38 +class EdenSpace;
1.39 +class ContiguousSpace;
1.40 +class ScanClosure;
1.41 +class STWGCTimer;
1.42 +
1.43 +// DefNewGeneration is a young generation containing eden, from- and
1.44 +// to-space.
1.45 +
1.46 +class DefNewGeneration: public Generation {
1.47 + friend class VMStructs;
1.48 +
1.49 +protected:
1.50 + Generation* _next_gen;
1.51 + uint _tenuring_threshold; // Tenuring threshold for next collection.
1.52 + ageTable _age_table;
1.53 + // Size of object to pretenure in words; command line provides bytes
1.54 + size_t _pretenure_size_threshold_words;
1.55 +
1.56 + ageTable* age_table() { return &_age_table; }
1.57 +
1.58 + // Initialize state to optimistically assume no promotion failure will
1.59 + // happen.
1.60 + void init_assuming_no_promotion_failure();
1.61 + // True iff a promotion has failed in the current collection.
1.62 + bool _promotion_failed;
1.63 + bool promotion_failed() { return _promotion_failed; }
1.64 + PromotionFailedInfo _promotion_failed_info;
1.65 +
1.66 + // Handling promotion failure. A young generation collection
1.67 + // can fail if a live object cannot be copied out of its
1.68 + // location in eden or from-space during the collection. If
1.69 + // a collection fails, the young generation is left in a
1.70 + // consistent state such that it can be collected by a
1.71 + // full collection.
1.72 + // Before the collection
1.73 + // Objects are in eden or from-space
1.74 + // All roots into the young generation point into eden or from-space.
1.75 + //
1.76 + // After a failed collection
1.77 + // Objects may be in eden, from-space, or to-space
1.78 + // An object A in eden or from-space may have a copy B
1.79 + // in to-space. If B exists, all roots that once pointed
1.80 + // to A must now point to B.
1.81 + // All objects in the young generation are unmarked.
1.82 + // Eden, from-space, and to-space will all be collected by
1.83 + // the full collection.
1.84 + void handle_promotion_failure(oop);
1.85 +
1.86 + // In the absence of promotion failure, we wouldn't look at "from-space"
1.87 + // objects after a young-gen collection. When promotion fails, however,
1.88 + // the subsequent full collection will look at from-space objects:
1.89 + // therefore we must remove their forwarding pointers.
1.90 + void remove_forwarding_pointers();
1.91 +
1.92 + // Preserve the mark of "obj", if necessary, in preparation for its mark
1.93 + // word being overwritten with a self-forwarding-pointer.
1.94 + void preserve_mark_if_necessary(oop obj, markOop m);
1.95 + void preserve_mark(oop obj, markOop m); // work routine used by the above
1.96 +
1.97 + // Together, these keep <object with a preserved mark, mark value> pairs.
1.98 + // They should always contain the same number of elements.
1.99 + Stack<oop, mtGC> _objs_with_preserved_marks;
1.100 + Stack<markOop, mtGC> _preserved_marks_of_objs;
1.101 +
1.102 + // Promotion failure handling
1.103 + ExtendedOopClosure *_promo_failure_scan_stack_closure;
1.104 + void set_promo_failure_scan_stack_closure(ExtendedOopClosure *scan_stack_closure) {
1.105 + _promo_failure_scan_stack_closure = scan_stack_closure;
1.106 + }
1.107 +
1.108 + Stack<oop, mtGC> _promo_failure_scan_stack;
1.109 + void drain_promo_failure_scan_stack(void);
1.110 + bool _promo_failure_drain_in_progress;
1.111 +
1.112 + // Performance Counters
1.113 + GenerationCounters* _gen_counters;
1.114 + CSpaceCounters* _eden_counters;
1.115 + CSpaceCounters* _from_counters;
1.116 + CSpaceCounters* _to_counters;
1.117 +
1.118 + // sizing information
1.119 + size_t _max_eden_size;
1.120 + size_t _max_survivor_size;
1.121 +
1.122 + // Allocation support
1.123 + bool _should_allocate_from_space;
1.124 + bool should_allocate_from_space() const {
1.125 + return _should_allocate_from_space;
1.126 + }
1.127 + void clear_should_allocate_from_space() {
1.128 + _should_allocate_from_space = false;
1.129 + }
1.130 + void set_should_allocate_from_space() {
1.131 + _should_allocate_from_space = true;
1.132 + }
1.133 +
1.134 + // Tenuring
1.135 + void adjust_desired_tenuring_threshold();
1.136 +
1.137 + // Spaces
1.138 + EdenSpace* _eden_space;
1.139 + ContiguousSpace* _from_space;
1.140 + ContiguousSpace* _to_space;
1.141 +
1.142 + STWGCTimer* _gc_timer;
1.143 +
1.144 + enum SomeProtectedConstants {
1.145 + // Generations are GenGrain-aligned and have size that are multiples of
1.146 + // GenGrain.
1.147 + MinFreeScratchWords = 100
1.148 + };
1.149 +
1.150 + // Return the size of a survivor space if this generation were of size
1.151 + // gen_size.
1.152 + size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
1.153 + size_t n = gen_size / (SurvivorRatio + 2);
1.154 + return n > alignment ? align_size_down(n, alignment) : alignment;
1.155 + }
1.156 +
1.157 + public: // was "protected" but caused compile error on win32
1.158 + class IsAliveClosure: public BoolObjectClosure {
1.159 + Generation* _g;
1.160 + public:
1.161 + IsAliveClosure(Generation* g);
1.162 + bool do_object_b(oop p);
1.163 + };
1.164 +
1.165 + class KeepAliveClosure: public OopClosure {
1.166 + protected:
1.167 + ScanWeakRefClosure* _cl;
1.168 + CardTableRS* _rs;
1.169 + template <class T> void do_oop_work(T* p);
1.170 + public:
1.171 + KeepAliveClosure(ScanWeakRefClosure* cl);
1.172 + virtual void do_oop(oop* p);
1.173 + virtual void do_oop(narrowOop* p);
1.174 + };
1.175 +
1.176 + class FastKeepAliveClosure: public KeepAliveClosure {
1.177 + protected:
1.178 + HeapWord* _boundary;
1.179 + template <class T> void do_oop_work(T* p);
1.180 + public:
1.181 + FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
1.182 + virtual void do_oop(oop* p);
1.183 + virtual void do_oop(narrowOop* p);
1.184 + };
1.185 +
1.186 + class EvacuateFollowersClosure: public VoidClosure {
1.187 + GenCollectedHeap* _gch;
1.188 + int _level;
1.189 + ScanClosure* _scan_cur_or_nonheap;
1.190 + ScanClosure* _scan_older;
1.191 + public:
1.192 + EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
1.193 + ScanClosure* cur, ScanClosure* older);
1.194 + void do_void();
1.195 + };
1.196 +
1.197 + class FastEvacuateFollowersClosure: public VoidClosure {
1.198 + GenCollectedHeap* _gch;
1.199 + int _level;
1.200 + DefNewGeneration* _gen;
1.201 + FastScanClosure* _scan_cur_or_nonheap;
1.202 + FastScanClosure* _scan_older;
1.203 + public:
1.204 + FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
1.205 + DefNewGeneration* gen,
1.206 + FastScanClosure* cur,
1.207 + FastScanClosure* older);
1.208 + void do_void();
1.209 + };
1.210 +
1.211 + public:
1.212 + DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
1.213 + const char* policy="Copy");
1.214 +
1.215 + virtual void ref_processor_init();
1.216 +
1.217 + virtual Generation::Name kind() { return Generation::DefNew; }
1.218 +
1.219 + // Accessing spaces
1.220 + EdenSpace* eden() const { return _eden_space; }
1.221 + ContiguousSpace* from() const { return _from_space; }
1.222 + ContiguousSpace* to() const { return _to_space; }
1.223 +
1.224 + virtual CompactibleSpace* first_compaction_space() const;
1.225 +
1.226 + // Space enquiries
1.227 + size_t capacity() const;
1.228 + size_t used() const;
1.229 + size_t free() const;
1.230 + size_t max_capacity() const;
1.231 + size_t capacity_before_gc() const;
1.232 + size_t unsafe_max_alloc_nogc() const;
1.233 + size_t contiguous_available() const;
1.234 +
1.235 + size_t max_eden_size() const { return _max_eden_size; }
1.236 + size_t max_survivor_size() const { return _max_survivor_size; }
1.237 +
1.238 + bool supports_inline_contig_alloc() const { return true; }
1.239 + HeapWord** top_addr() const;
1.240 + HeapWord** end_addr() const;
1.241 +
1.242 + // Thread-local allocation buffers
1.243 + bool supports_tlab_allocation() const { return true; }
1.244 + size_t tlab_capacity() const;
1.245 + size_t tlab_used() const;
1.246 + size_t unsafe_max_tlab_alloc() const;
1.247 +
1.248 + // Grow the generation by the specified number of bytes.
1.249 + // The size of bytes is assumed to be properly aligned.
1.250 + // Return true if the expansion was successful.
1.251 + bool expand(size_t bytes);
1.252 +
1.253 + // DefNewGeneration cannot currently expand except at
1.254 + // a GC.
1.255 + virtual bool is_maximal_no_gc() const { return true; }
1.256 +
1.257 + // Iteration
1.258 + void object_iterate(ObjectClosure* blk);
1.259 +
1.260 + void younger_refs_iterate(OopsInGenClosure* cl);
1.261 +
1.262 + void space_iterate(SpaceClosure* blk, bool usedOnly = false);
1.263 +
1.264 + // Allocation support
1.265 + virtual bool should_allocate(size_t word_size, bool is_tlab) {
1.266 + assert(UseTLAB || !is_tlab, "Should not allocate tlab");
1.267 +
1.268 + size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
1.269 +
1.270 + const bool non_zero = word_size > 0;
1.271 + const bool overflows = word_size >= overflow_limit;
1.272 + const bool check_too_big = _pretenure_size_threshold_words > 0;
1.273 + const bool not_too_big = word_size < _pretenure_size_threshold_words;
1.274 + const bool size_ok = is_tlab || !check_too_big || not_too_big;
1.275 +
1.276 + bool result = !overflows &&
1.277 + non_zero &&
1.278 + size_ok;
1.279 +
1.280 + return result;
1.281 + }
1.282 +
1.283 + HeapWord* allocate(size_t word_size, bool is_tlab);
1.284 + HeapWord* allocate_from_space(size_t word_size);
1.285 +
1.286 + HeapWord* par_allocate(size_t word_size, bool is_tlab);
1.287 +
1.288 + // Prologue & Epilogue
1.289 + virtual void gc_prologue(bool full);
1.290 + virtual void gc_epilogue(bool full);
1.291 +
1.292 + // Save the tops for eden, from, and to
1.293 + virtual void record_spaces_top();
1.294 +
1.295 + // Doesn't require additional work during GC prologue and epilogue
1.296 + virtual bool performs_in_place_marking() const { return false; }
1.297 +
1.298 + // Accessing marks
1.299 + void save_marks();
1.300 + void reset_saved_marks();
1.301 + bool no_allocs_since_save_marks();
1.302 +
1.303 + // Need to declare the full complement of closures, whether we'll
1.304 + // override them or not, or get message from the compiler:
1.305 + // oop_since_save_marks_iterate_nv hides virtual function...
1.306 +#define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
1.307 + void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
1.308 +
1.309 + ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
1.310 +
1.311 +#undef DefNew_SINCE_SAVE_MARKS_DECL
1.312 +
1.313 + // For non-youngest collection, the DefNewGeneration can contribute
1.314 + // "to-space".
1.315 + virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor,
1.316 + size_t max_alloc_words);
1.317 +
1.318 + // Reset for contribution of "to-space".
1.319 + virtual void reset_scratch();
1.320 +
1.321 + // GC support
1.322 + virtual void compute_new_size();
1.323 +
1.324 + // Returns true if the collection is likely to be safely
1.325 + // completed. Even if this method returns true, a collection
1.326 + // may not be guaranteed to succeed, and the system should be
1.327 + // able to safely unwind and recover from that failure, albeit
1.328 + // at some additional cost. Override superclass's implementation.
1.329 + virtual bool collection_attempt_is_safe();
1.330 +
1.331 + virtual void collect(bool full,
1.332 + bool clear_all_soft_refs,
1.333 + size_t size,
1.334 + bool is_tlab);
1.335 + HeapWord* expand_and_allocate(size_t size,
1.336 + bool is_tlab,
1.337 + bool parallel = false);
1.338 +
1.339 + oop copy_to_survivor_space(oop old);
1.340 + uint tenuring_threshold() { return _tenuring_threshold; }
1.341 +
1.342 + // Performance Counter support
1.343 + void update_counters();
1.344 +
1.345 + // Printing
1.346 + virtual const char* name() const;
1.347 + virtual const char* short_name() const { return "DefNew"; }
1.348 +
1.349 + bool must_be_youngest() const { return true; }
1.350 + bool must_be_oldest() const { return false; }
1.351 +
1.352 + // PrintHeapAtGC support.
1.353 + void print_on(outputStream* st) const;
1.354 +
1.355 + void verify();
1.356 +
1.357 + bool promo_failure_scan_is_complete() const {
1.358 + return _promo_failure_scan_stack.is_empty();
1.359 + }
1.360 +
1.361 + protected:
1.362 + // If clear_space is true, clear the survivor spaces. Eden is
1.363 + // cleared if the minimum size of eden is 0. If mangle_space
1.364 + // is true, also mangle the space in debug mode.
1.365 + void compute_space_boundaries(uintx minimum_eden_size,
1.366 + bool clear_space,
1.367 + bool mangle_space);
1.368 + // Scavenge support
1.369 + void swap_spaces();
1.370 +};
1.371 +
1.372 +#endif // SHARE_VM_MEMORY_DEFNEWGENERATION_HPP
