Mercurial > hg > graal-compiler
diff src/share/vm/memory/genCollectedHeap.hpp @ 0:a61af66fc99e jdk7-b24
Initial load
author | duke |
---|---|
date | Sat, 01 Dec 2007 00:00:00 +0000 |
parents | |
children | ba764ed4b6f2 c0492d52d55b |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/memory/genCollectedHeap.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,491 @@ +/* + * 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; +};