truffle: src/share/vm/memory/genCollectedHeap.hpp comparison

comparison src/share/vm/memory/genCollectedHeap.hpp @ 0:a61af66fc99e jdk7-b24

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author	duke
date	Sat, 01 Dec 2007 00:00:00 +0000
parents
children	ba764ed4b6f2 c0492d52d55b

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+:a61af66fc99e
+/*
+* Copyright 2000-2007 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 SubTasksDone;
+// A "GenCollectedHeap" is a SharedHeap that uses generational
+// collection.  It is represented with a sequence of Generation's.
+class GenCollectedHeap : public SharedHeap {
+friend class GenCollectorPolicy;
+friend class Generation;
+friend class DefNewGeneration;
+friend class TenuredGeneration;
+friend class ConcurrentMarkSweepGeneration;
+friend class CMSCollector;
+friend class GenMarkSweep;
+friend class VM_GenCollectForAllocation;
+friend class VM_GenCollectFull;
+friend class VM_GenCollectFullConcurrent;
+friend class VM_GC_HeapInspection;
+friend class VM_HeapDumper;
+friend class HeapInspection;
+friend class GCCauseSetter;
+friend class VMStructs;
+public:
+enum SomeConstants {
+max_gens = 10
+};
+friend class VM_PopulateDumpSharedSpace;
+protected:
+// Fields:
+static GenCollectedHeap* _gch;
+private:
+int _n_gens;
+Generation* _gens[max_gens];
+GenerationSpec** _gen_specs;
+// The generational collector policy.
+GenCollectorPolicy* _gen_policy;
+// If a generation would bail out of an incremental collection,
+// it sets this flag.  If the flag is set, satisfy_failed_allocation
+// will attempt allocating in all generations before doing a full GC.
+bool _incremental_collection_will_fail;
+bool _last_incremental_collection_failed;
+// In support of ExplicitGCInvokesConcurrent functionality
+unsigned int _full_collections_completed;
+// Data structure for claiming the (potentially) parallel tasks in
+// (gen-specific) strong roots processing.
+SubTasksDone* _gen_process_strong_tasks;
+// In block contents verification, the number of header words to skip
+NOT_PRODUCT(static size_t _skip_header_HeapWords;)
+// GC is not allowed during the dump of the shared classes.  Keep track
+// of this in order to provide an reasonable error message when terminating.
+bool _preloading_shared_classes;
+protected:
+// Directs each generation up to and including "collectedGen" to recompute
+// its desired size.
+void compute_new_generation_sizes(int collectedGen);
+// Helper functions for allocation
+HeapWord* attempt_allocation(size_t size,
+bool   is_tlab,
+bool   first_only);
+// Helper function for two callbacks below.
+// Considers collection of the first max_level+1 generations.
+void do_collection(bool   full,
+bool   clear_all_soft_refs,
+size_t size,
+bool   is_tlab,
+int    max_level);
+// Callback from VM_GenCollectForAllocation operation.
+// This function does everything necessary/possible to satisfy an
+// allocation request that failed in the youngest generation that should
+// have handled it (including collection, expansion, etc.)
+HeapWord* satisfy_failed_allocation(size_t size, bool is_tlab);
+// Callback from VM_GenCollectFull operation.
+// Perform a full collection of the first max_level+1 generations.
+void do_full_collection(bool clear_all_soft_refs, int max_level);
+// Does the "cause" of GC indicate that
+// we absolutely __must__ clear soft refs?
+bool must_clear_all_soft_refs();
+public:
+GenCollectedHeap(GenCollectorPolicy *policy);
+GCStats* gc_stats(int level) const;
+// Returns JNI_OK on success
+virtual jint initialize();
+char* allocate(size_t alignment, PermanentGenerationSpec* perm_gen_spec,
+size_t* _total_reserved, int* _n_covered_regions,
+ReservedSpace* heap_rs);
+// Does operations required after initialization has been done.
+void post_initialize();
+// Initialize ("weak") refs processing support
+virtual void ref_processing_init();
+virtual CollectedHeap::Name kind() const {
+return CollectedHeap::GenCollectedHeap;
+}
+// The generational collector policy.
+GenCollectorPolicy* gen_policy() const { return _gen_policy; }
+// Adaptive size policy
+virtual AdaptiveSizePolicy* size_policy() {
+return gen_policy()->size_policy();
+}
+size_t capacity() const;
+size_t used() const;
+// Save the "used_region" for generations level and lower,
+// and, if perm is true, for perm gen.
+void save_used_regions(int level, bool perm);
+size_t max_capacity() const;
+HeapWord* mem_allocate(size_t size,
+bool   is_large_noref,
+bool   is_tlab,
+bool*  gc_overhead_limit_was_exceeded);
+// We may support a shared contiguous allocation area, if the youngest
+// generation does.
+bool supports_inline_contig_alloc() const;
+HeapWord** top_addr() const;
+HeapWord** end_addr() const;
+// Return an estimate of the maximum allocation that could be performed
+// without triggering any collection activity.  In a generational
+// collector, for example, this is probably the largest allocation that
+// could be supported in the youngest generation.  It is "unsafe" because
+// no locks are taken; the result should be treated as an approximation,
+// not a guarantee.
+size_t unsafe_max_alloc();
+// Does this heap support heap inspection? (+PrintClassHistogram)
+virtual bool supports_heap_inspection() const { return true; }
+// Perform a full collection of the heap; intended for use in implementing
+// "System.gc". This implies as full a collection as the CollectedHeap
+// supports. Caller does not hold the Heap_lock on entry.
+void collect(GCCause::Cause cause);
+// This interface assumes that it's being called by the
+// vm thread. It collects the heap assuming that the
+// heap lock is already held and that we are executing in
+// the context of the vm thread.
+void collect_as_vm_thread(GCCause::Cause cause);
+// The same as above but assume that the caller holds the Heap_lock.
+void collect_locked(GCCause::Cause cause);
+// Perform a full collection of the first max_level+1 generations.
+// Mostly used for testing purposes. Caller does not hold the Heap_lock on entry.
+void collect(GCCause::Cause cause, int max_level);
+// Returns "TRUE" iff "p" points into the allocated area of the heap.
+// The methods is_in(), is_in_closed_subset() and is_in_youngest() may
+// be expensive to compute in general, so, to prevent
+// their inadvertent use in product jvm's, we restrict their use to
+// assertion checking or verification only.
+bool is_in(const void* p) const;
+// override
+bool is_in_closed_subset(const void* p) const {
+if (UseConcMarkSweepGC) {
+return is_in_reserved(p);
+} else {
+return is_in(p);
+}
+}
+// Returns "TRUE" iff "p" points into the youngest generation.
+bool is_in_youngest(void* p);
+// Iteration functions.
+void oop_iterate(OopClosure* cl);
+void oop_iterate(MemRegion mr, OopClosure* cl);
+void object_iterate(ObjectClosure* cl);
+void object_iterate_since_last_GC(ObjectClosure* cl);
+Space* space_containing(const void* addr) const;
+// A CollectedHeap is divided into a dense sequence of "blocks"; that is,
+// each address in the (reserved) heap is a member of exactly
+// one block.  The defining characteristic of a block is that it is
+// possible to find its size, and thus to progress forward to the next
+// block.  (Blocks may be of different sizes.)  Thus, blocks may
+// represent Java objects, or they might be free blocks in a
+// free-list-based heap (or subheap), as long as the two kinds are
+// distinguishable and the size of each is determinable.
+// Returns the address of the start of the "block" that contains the
+// address "addr".  We say "blocks" instead of "object" since some heaps
+// may not pack objects densely; a chunk may either be an object or a
+// non-object.
+virtual HeapWord* block_start(const void* addr) const;
+// Requires "addr" to be the start of a chunk, and returns its size.
+// "addr + size" is required to be the start of a new chunk, or the end
+// of the active area of the heap. Assumes (and verifies in non-product
+// builds) that addr is in the allocated part of the heap and is
+// the start of a chunk.
+virtual size_t block_size(const HeapWord* addr) const;
+// Requires "addr" to be the start of a block, and returns "TRUE" iff
+// the block is an object. Assumes (and verifies in non-product
+// builds) that addr is in the allocated part of the heap and is
+// the start of a chunk.
+virtual bool block_is_obj(const HeapWord* addr) const;
+// Section on TLAB's.
+virtual bool supports_tlab_allocation() const;
+virtual size_t tlab_capacity(Thread* thr) const;
+virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
+virtual HeapWord* allocate_new_tlab(size_t size);
+// The "requestor" generation is performing some garbage collection
+// action for which it would be useful to have scratch space.  The
+// requestor promises to allocate no more than "max_alloc_words" in any
+// older generation (via promotion say.)   Any blocks of space that can
+// be provided are returned as a list of ScratchBlocks, sorted by
+// decreasing size.
+ScratchBlock* gather_scratch(Generation* requestor, size_t max_alloc_words);
+size_t large_typearray_limit();
+// Ensure parsability: override
+virtual void ensure_parsability(bool retire_tlabs);
+// Time in ms since the longest time a collector ran in
+// in any generation.
+virtual jlong millis_since_last_gc();
+// Total number of full collections completed.
+unsigned int total_full_collections_completed() {
+assert(_full_collections_completed <= _total_full_collections,
+"Can't complete more collections than were started");
+return _full_collections_completed;
+}
+// Update above counter, as appropriate, at the end of a stop-world GC cycle
+unsigned int update_full_collections_completed();
+// Update above counter, as appropriate, at the end of a concurrent GC cycle
+unsigned int update_full_collections_completed(unsigned int count);
+// Update "time of last gc" for all constituent generations
+// to "now".
+void update_time_of_last_gc(jlong now) {
+for (int i = 0; i < _n_gens; i++) {
+_gens[i]->update_time_of_last_gc(now);
+}
+perm_gen()->update_time_of_last_gc(now);
+}
+// Update the gc statistics for each generation.
+// "level" is the level of the lastest collection
+void update_gc_stats(int current_level, bool full) {
+for (int i = 0; i < _n_gens; i++) {
+_gens[i]->update_gc_stats(current_level, full);
+}
+perm_gen()->update_gc_stats(current_level, full);
+}
+// Override.
+bool no_gc_in_progress() { return !is_gc_active(); }
+// Override.
+void prepare_for_verify();
+// Override.
+void verify(bool allow_dirty, bool silent);
+// Override.
+void print() const;
+void print_on(outputStream* st) const;
+virtual void print_gc_threads_on(outputStream* st) const;
+virtual void gc_threads_do(ThreadClosure* tc) const;
+virtual void print_tracing_info() const;
+// PrintGC, PrintGCDetails support
+void print_heap_change(size_t prev_used) const;
+void print_perm_heap_change(size_t perm_prev_used) const;
+// The functions below are helper functions that a subclass of
+// "CollectedHeap" can use in the implementation of its virtual
+// functions.
+class GenClosure : public StackObj {
+public:
+virtual void do_generation(Generation* gen) = 0;
+};
+// Apply "cl.do_generation" to all generations in the heap (not including
+// the permanent generation).  If "old_to_young" determines the order.
+void generation_iterate(GenClosure* cl, bool old_to_young);
+void space_iterate(SpaceClosure* cl);
+// Return "true" if all generations (but perm) have reached the
+// maximal committed limit that they can reach, without a garbage
+// collection.
+virtual bool is_maximal_no_gc() const;
+// Return the generation before "gen", or else NULL.
+Generation* prev_gen(Generation* gen) const {
+int l = gen->level();
+if (l == 0) return NULL;
+else return _gens[l-1];
+}
+// Return the generation after "gen", or else NULL.
+Generation* next_gen(Generation* gen) const {
+int l = gen->level() + 1;
+if (l == _n_gens) return NULL;
+else return _gens[l];
+}
+Generation* get_gen(int i) const {
+if (i >= 0 && i < _n_gens)
+return _gens[i];
+else
+return NULL;
+}
+int n_gens() const {
+assert(_n_gens == gen_policy()->number_of_generations(), "Sanity");
+return _n_gens;
+}
+// Convenience function to be used in situations where the heap type can be
+// asserted to be this type.
+static GenCollectedHeap* heap();
+void set_par_threads(int t);
+// Invoke the "do_oop" method of one of the closures "not_older_gens"
+// or "older_gens" on root locations for the generation at
+// "level".  (The "older_gens" closure is used for scanning references
+// from older generations; "not_older_gens" is used everywhere else.)
+// If "younger_gens_as_roots" is false, younger generations are
+// not scanned as roots; in this case, the caller must be arranging to
+// scan the younger generations itself.  (For example, a generation might
+// explicitly mark reachable objects in younger generations, to avoid
+// excess storage retention.)  If "collecting_perm_gen" is false, then
+// roots that may only contain references to permGen objects are not
+// scanned. The "so" argument determines which of the roots
+// the closure is applied to:
+// "SO_None" does none;
+// "SO_AllClasses" applies the closure to all entries in the SystemDictionary;
+// "SO_SystemClasses" to all the "system" classes and loaders;
+// "SO_Symbols_and_Strings" applies the closure to all entries in
+// SymbolsTable and StringTable.
+void gen_process_strong_roots(int level, bool younger_gens_as_roots,
+bool collecting_perm_gen,
+SharedHeap::ScanningOption so,
+OopsInGenClosure* older_gens,
+OopsInGenClosure* not_older_gens);
+// Apply "blk" to all the weak roots of the system.  These include
+// JNI weak roots, the code cache, system dictionary, symbol table,
+// string table, and referents of reachable weak refs.
+void gen_process_weak_roots(OopClosure* root_closure,
+OopClosure* non_root_closure);
+// Set the saved marks of generations, if that makes sense.
+// In particular, if any generation might iterate over the oops
+// in other generations, it should call this method.
+void save_marks();
+// Apply "cur->do_oop" or "older->do_oop" to all the oops in objects
+// allocated since the last call to save_marks in generations at or above
+// "level" (including the permanent generation.)  The "cur" closure is
+// applied to references in the generation at "level", and the "older"
+// closure to older (and permanent) generations.
+#define GCH_SINCE_SAVE_MARKS_ITERATE_DECL(OopClosureType, nv_suffix)    \
+void oop_since_save_marks_iterate(int level,                          \
+OopClosureType* cur,                \
+OopClosureType* older);
+ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DECL)
+#undef GCH_SINCE_SAVE_MARKS_ITERATE_DECL
+// Returns "true" iff no allocations have occurred in any generation at
+// "level" or above (including the permanent generation) since the last
+// call to "save_marks".
+bool no_allocs_since_save_marks(int level);
+// If a generation bails out of an incremental collection,
+// it sets this flag.
+bool incremental_collection_will_fail() {
+return _incremental_collection_will_fail;
+}
+void set_incremental_collection_will_fail() {
+_incremental_collection_will_fail = true;
+}
+void clear_incremental_collection_will_fail() {
+_incremental_collection_will_fail = false;
+}
+bool last_incremental_collection_failed() const {
+return _last_incremental_collection_failed;
+}
+void set_last_incremental_collection_failed() {
+_last_incremental_collection_failed = true;
+}
+void clear_last_incremental_collection_failed() {
+_last_incremental_collection_failed = false;
+}
+// Promotion of obj into gen failed.  Try to promote obj to higher non-perm
+// gens in ascending order; return the new location of obj if successful.
+// Otherwise, try expand-and-allocate for obj in each generation starting at
+// gen; return the new location of obj if successful.  Otherwise, return NULL.
+oop handle_failed_promotion(Generation* gen,
+oop obj,
+size_t obj_size,
+oop* ref);
+private:
+// Accessor for memory state verification support
+NOT_PRODUCT(
+static size_t skip_header_HeapWords() { return _skip_header_HeapWords; }
+)
+// Override
+void check_for_non_bad_heap_word_value(HeapWord* addr,
+size_t size) PRODUCT_RETURN;
+// For use by mark-sweep.  As implemented, mark-sweep-compact is global
+// in an essential way: compaction is performed across generations, by
+// iterating over spaces.
+void prepare_for_compaction();
+// Perform a full collection of the first max_level+1 generations.
+// This is the low level interface used by the public versions of
+// collect() and collect_locked(). Caller holds the Heap_lock on entry.
+void collect_locked(GCCause::Cause cause, int max_level);
+// Returns success or failure.
+bool create_cms_collector();
+// In support of ExplicitGCInvokesConcurrent functionality
+bool should_do_concurrent_full_gc(GCCause::Cause cause);
+void collect_mostly_concurrent(GCCause::Cause cause);
+protected:
+virtual void gc_prologue(bool full);
+virtual void gc_epilogue(bool full);
+public:
+virtual void preload_and_dump(TRAPS) KERNEL_RETURN;
+};

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comparison src/share/vm/memory/genCollectedHeap.hpp @ 0:a61af66fc99e jdk7-b24