--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/memory/defNewGeneration.hpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,332 @@
+/*
+ * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+class EdenSpace;
+class ContiguousSpace;
+
+// DefNewGeneration is a young generation containing eden, from- and
+// to-space.
+
+class DefNewGeneration: public Generation {
+ friend class VMStructs;
+
+protected:
+ Generation* _next_gen;
+ int _tenuring_threshold; // Tenuring threshold for next collection.
+ ageTable _age_table;
+ // Size of object to pretenure in words; command line provides bytes
+ size_t _pretenure_size_threshold_words;
+
+ ageTable* age_table() { return &_age_table; }
+ // Initialize state to optimistically assume no promotion failure will
+ // happen.
+ void init_assuming_no_promotion_failure();
+ // True iff a promotion has failed in the current collection.
+ bool _promotion_failed;
+ bool promotion_failed() { return _promotion_failed; }
+
+ // Handling promotion failure. A young generation collection
+ // can fail if a live object cannot be copied out of its
+ // location in eden or from-space during the collection. If
+ // a collection fails, the young generation is left in a
+ // consistent state such that it can be collected by a
+ // full collection.
+ // Before the collection
+ // Objects are in eden or from-space
+ // All roots into the young generation point into eden or from-space.
+ //
+ // After a failed collection
+ // Objects may be in eden, from-space, or to-space
+ // An object A in eden or from-space may have a copy B
+ // in to-space. If B exists, all roots that once pointed
+ // to A must now point to B.
+ // All objects in the young generation are unmarked.
+ // Eden, from-space, and to-space will all be collected by
+ // the full collection.
+ void handle_promotion_failure(oop);
+
+ // In the absence of promotion failure, we wouldn't look at "from-space"
+ // objects after a young-gen collection. When promotion fails, however,
+ // the subsequent full collection will look at from-space objects:
+ // therefore we must remove their forwarding pointers.
+ void remove_forwarding_pointers();
+
+ // Preserve the mark of "obj", if necessary, in preparation for its mark
+ // word being overwritten with a self-forwarding-pointer.
+ void preserve_mark_if_necessary(oop obj, markOop m);
+
+ // When one is non-null, so is the other. Together, they each pair is
+ // an object with a preserved mark, and its mark value.
+ GrowableArray<oop>* _objs_with_preserved_marks;
+ GrowableArray<markOop>* _preserved_marks_of_objs;
+
+ // Returns true if the collection can be safely attempted.
+ // If this method returns false, a collection is not
+ // guaranteed to fail but the system may not be able
+ // to recover from the failure.
+ bool collection_attempt_is_safe();
+
+ // Promotion failure handling
+ OopClosure *_promo_failure_scan_stack_closure;
+ void set_promo_failure_scan_stack_closure(OopClosure *scan_stack_closure) {
+ _promo_failure_scan_stack_closure = scan_stack_closure;
+ }
+
+ GrowableArray<oop>* _promo_failure_scan_stack;
+ GrowableArray<oop>* promo_failure_scan_stack() const {
+ return _promo_failure_scan_stack;
+ }
+ void push_on_promo_failure_scan_stack(oop);
+ void drain_promo_failure_scan_stack(void);
+ bool _promo_failure_drain_in_progress;
+
+ // Performance Counters
+ GenerationCounters* _gen_counters;
+ CSpaceCounters* _eden_counters;
+ CSpaceCounters* _from_counters;
+ CSpaceCounters* _to_counters;
+
+ // sizing information
+ size_t _max_eden_size;
+ size_t _max_survivor_size;
+
+ // Allocation support
+ bool _should_allocate_from_space;
+ bool should_allocate_from_space() const {
+ return _should_allocate_from_space;
+ }
+ void clear_should_allocate_from_space() {
+ _should_allocate_from_space = false;
+ }
+ void set_should_allocate_from_space() {
+ _should_allocate_from_space = true;
+ }
+
+ protected:
+ // Spaces
+ EdenSpace* _eden_space;
+ ContiguousSpace* _from_space;
+ ContiguousSpace* _to_space;
+
+ enum SomeProtectedConstants {
+ // Generations are GenGrain-aligned and have size that are multiples of
+ // GenGrain.
+ MinFreeScratchWords = 100
+ };
+
+ // Return the size of a survivor space if this generation were of size
+ // gen_size.
+ size_t compute_survivor_size(size_t gen_size, size_t alignment) const {
+ size_t n = gen_size / (SurvivorRatio + 2);
+ return n > alignment ? align_size_down(n, alignment) : alignment;
+ }
+
+ public: // was "protected" but caused compile error on win32
+ class IsAliveClosure: public BoolObjectClosure {
+ Generation* _g;
+ public:
+ IsAliveClosure(Generation* g);
+ void do_object(oop p);
+ bool do_object_b(oop p);
+ };
+
+ class KeepAliveClosure: public OopClosure {
+ protected:
+ ScanWeakRefClosure* _cl;
+ CardTableRS* _rs;
+ public:
+ KeepAliveClosure(ScanWeakRefClosure* cl);
+ void do_oop(oop* p);
+ };
+
+ class FastKeepAliveClosure: public KeepAliveClosure {
+ protected:
+ HeapWord* _boundary;
+ public:
+ FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl);
+ void do_oop(oop* p);
+ };
+
+ class EvacuateFollowersClosure: public VoidClosure {
+ GenCollectedHeap* _gch;
+ int _level;
+ ScanClosure* _scan_cur_or_nonheap;
+ ScanClosure* _scan_older;
+ public:
+ EvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+ ScanClosure* cur, ScanClosure* older);
+ void do_void();
+ };
+
+ class FastEvacuateFollowersClosure;
+ friend class FastEvacuateFollowersClosure;
+ class FastEvacuateFollowersClosure: public VoidClosure {
+ GenCollectedHeap* _gch;
+ int _level;
+ DefNewGeneration* _gen;
+ FastScanClosure* _scan_cur_or_nonheap;
+ FastScanClosure* _scan_older;
+ public:
+ FastEvacuateFollowersClosure(GenCollectedHeap* gch, int level,
+ DefNewGeneration* gen,
+ FastScanClosure* cur,
+ FastScanClosure* older);
+ void do_void();
+ };
+
+ public:
+ DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level,
+ const char* policy="Copy");
+
+ virtual Generation::Name kind() { return Generation::DefNew; }
+
+ // Accessing spaces
+ EdenSpace* eden() const { return _eden_space; }
+ ContiguousSpace* from() const { return _from_space; }
+ ContiguousSpace* to() const { return _to_space; }
+
+ inline CompactibleSpace* first_compaction_space() const;
+
+ // Space enquiries
+ size_t capacity() const;
+ size_t used() const;
+ size_t free() const;
+ size_t max_capacity() const;
+ size_t capacity_before_gc() const;
+ size_t unsafe_max_alloc_nogc() const;
+ size_t contiguous_available() const;
+
+ size_t max_eden_size() const { return _max_eden_size; }
+ size_t max_survivor_size() const { return _max_survivor_size; }
+
+ bool supports_inline_contig_alloc() const { return true; }
+ HeapWord** top_addr() const;
+ HeapWord** end_addr() const;
+
+ // Thread-local allocation buffers
+ bool supports_tlab_allocation() const { return true; }
+ inline size_t tlab_capacity() const;
+ inline size_t unsafe_max_tlab_alloc() const;
+
+ // Grow the generation by the specified number of bytes.
+ // The size of bytes is assumed to be properly aligned.
+ // Return true if the expansion was successful.
+ bool expand(size_t bytes);
+
+ // DefNewGeneration cannot currently expand except at
+ // a GC.
+ virtual bool is_maximal_no_gc() const { return true; }
+
+ // Iteration
+ void object_iterate(ObjectClosure* blk);
+ void object_iterate_since_last_GC(ObjectClosure* cl);
+
+ void younger_refs_iterate(OopsInGenClosure* cl);
+
+ void space_iterate(SpaceClosure* blk, bool usedOnly = false);
+
+ // Allocation support
+ virtual bool should_allocate(size_t word_size, bool is_tlab) {
+ assert(UseTLAB || !is_tlab, "Should not allocate tlab");
+
+ size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize);
+
+ const bool non_zero = word_size > 0;
+ const bool overflows = word_size >= overflow_limit;
+ const bool check_too_big = _pretenure_size_threshold_words > 0;
+ const bool not_too_big = word_size < _pretenure_size_threshold_words;
+ const bool size_ok = is_tlab || !check_too_big || not_too_big;
+
+ bool result = !overflows &&
+ non_zero &&
+ size_ok;
+
+ return result;
+ }
+
+ inline HeapWord* allocate(size_t word_size, bool is_tlab);
+ HeapWord* allocate_from_space(size_t word_size);
+
+ inline HeapWord* par_allocate(size_t word_size, bool is_tlab);
+
+ // Prologue & Epilogue
+ inline virtual void gc_prologue(bool full);
+ virtual void gc_epilogue(bool full);
+
+ // Doesn't require additional work during GC prologue and epilogue
+ virtual bool performs_in_place_marking() const { return false; }
+
+ // Accessing marks
+ void save_marks();
+ void reset_saved_marks();
+ bool no_allocs_since_save_marks();
+
+ // Need to declare the full complement of closures, whether we'll
+ // override them or not, or get message from the compiler:
+ // oop_since_save_marks_iterate_nv hides virtual function...
+#define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \
+ void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl);
+
+ ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL)
+
+#undef DefNew_SINCE_SAVE_MARKS_DECL
+
+ // For non-youngest collection, the DefNewGeneration can contribute
+ // "to-space".
+ void contribute_scratch(ScratchBlock*& list, Generation* requestor,
+ size_t max_alloc_words);
+
+ // GC support
+ virtual void compute_new_size();
+ virtual void collect(bool full,
+ bool clear_all_soft_refs,
+ size_t size,
+ bool is_tlab);
+ HeapWord* expand_and_allocate(size_t size,
+ bool is_tlab,
+ bool parallel = false);
+
+ oop copy_to_survivor_space(oop old, oop* from);
+ int tenuring_threshold() { return _tenuring_threshold; }
+
+ // Performance Counter support
+ void update_counters();
+
+ // Printing
+ virtual const char* name() const;
+ virtual const char* short_name() const { return "DefNew"; }
+
+ bool must_be_youngest() const { return true; }
+ bool must_be_oldest() const { return false; }
+
+ // PrintHeapAtGC support.
+ void print_on(outputStream* st) const;
+
+ void verify(bool allow_dirty);
+
+ protected:
+ void compute_space_boundaries(uintx minimum_eden_size);
+ // Scavenge support
+ void swap_spaces();
+};