--- old/src/share/vm/gc_interface/collectedHeap.hpp 2015-05-12 11:56:39.077319033 +0200 +++ /dev/null 2015-03-18 17:10:38.111854831 +0100 @@ -1,639 +0,0 @@ -/* - * Copyright (c) 2001, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA - * or visit www.oracle.com if you need additional information or have any - * questions. - * - */ - -#ifndef SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP -#define SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP - -#include "gc_interface/gcCause.hpp" -#include "gc_implementation/shared/gcWhen.hpp" -#include "memory/allocation.hpp" -#include "runtime/handles.hpp" -#include "runtime/perfData.hpp" -#include "runtime/safepoint.hpp" -#include "utilities/events.hpp" - -// A "CollectedHeap" is an implementation of a java heap for HotSpot. This -// is an abstract class: there may be many different kinds of heaps. This -// class defines the functions that a heap must implement, and contains -// infrastructure common to all heaps. - -class AdaptiveSizePolicy; -class BarrierSet; -class CollectorPolicy; -class GCHeapSummary; -class GCTimer; -class GCTracer; -class MetaspaceSummary; -class Thread; -class ThreadClosure; -class VirtualSpaceSummary; -class nmethod; - -class GCMessage : public FormatBuffer<1024> { - public: - bool is_before; - - public: - GCMessage() {} -}; - -class GCHeapLog : public EventLogBase { - private: - void log_heap(bool before); - - public: - GCHeapLog() : EventLogBase("GC Heap History") {} - - void log_heap_before() { - log_heap(true); - } - void log_heap_after() { - log_heap(false); - } -}; - -// -// CollectedHeap -// GenCollectedHeap -// G1CollectedHeap -// ParallelScavengeHeap -// -class CollectedHeap : public CHeapObj { - friend class VMStructs; - friend class IsGCActiveMark; // Block structured external access to _is_gc_active - - private: -#ifdef ASSERT - static int _fire_out_of_memory_count; -#endif - - // Used for filler objects (static, but initialized in ctor). - static size_t _filler_array_max_size; - - GCHeapLog* _gc_heap_log; - - // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 is being used - bool _defer_initial_card_mark; - - MemRegion _reserved; - - protected: - BarrierSet* _barrier_set; - bool _is_gc_active; - uint _n_par_threads; - - unsigned int _total_collections; // ... started - unsigned int _total_full_collections; // ... started - NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) - NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) - - // Reason for current garbage collection. Should be set to - // a value reflecting no collection between collections. - GCCause::Cause _gc_cause; - GCCause::Cause _gc_lastcause; - PerfStringVariable* _perf_gc_cause; - PerfStringVariable* _perf_gc_lastcause; - - // Constructor - CollectedHeap(); - - // Do common initializations that must follow instance construction, - // for example, those needing virtual calls. - // This code could perhaps be moved into initialize() but would - // be slightly more awkward because we want the latter to be a - // pure virtual. - void pre_initialize(); - - // Create a new tlab. All TLAB allocations must go through this. - virtual HeapWord* allocate_new_tlab(size_t size); - - // Accumulate statistics on all tlabs. - virtual void accumulate_statistics_all_tlabs(); - - // Reinitialize tlabs before resuming mutators. - virtual void resize_all_tlabs(); - - // Allocate from the current thread's TLAB, with broken-out slow path. - inline static HeapWord* allocate_from_tlab(KlassHandle klass, Thread* thread, size_t size); - static HeapWord* allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size); - - // Allocate an uninitialized block of the given size, or returns NULL if - // this is impossible. - inline static HeapWord* common_mem_allocate_noinit(KlassHandle klass, size_t size, TRAPS); - - // Like allocate_init, but the block returned by a successful allocation - // is guaranteed initialized to zeros. - inline static HeapWord* common_mem_allocate_init(KlassHandle klass, size_t size, TRAPS); - - // Helper functions for (VM) allocation. - inline static void post_allocation_setup_common(KlassHandle klass, HeapWord* obj); - inline static void post_allocation_setup_no_klass_install(KlassHandle klass, - HeapWord* objPtr); - - inline static void post_allocation_setup_obj(KlassHandle klass, HeapWord* obj, int size); - - inline static void post_allocation_setup_array(KlassHandle klass, - HeapWord* obj, int length); - - // Clears an allocated object. - inline static void init_obj(HeapWord* obj, size_t size); - - // Filler object utilities. - static inline size_t filler_array_hdr_size(); - static inline size_t filler_array_min_size(); - - DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) - DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) - - // Fill with a single array; caller must ensure filler_array_min_size() <= - // words <= filler_array_max_size(). - static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); - - // Fill with a single object (either an int array or a java.lang.Object). - static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); - - virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer); - - // Verification functions - virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) - PRODUCT_RETURN; - virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) - PRODUCT_RETURN; - debug_only(static void check_for_valid_allocation_state();) - - public: - enum Name { - GenCollectedHeap, - ParallelScavengeHeap, - G1CollectedHeap - }; - - static inline size_t filler_array_max_size() { - return _filler_array_max_size; - } - - virtual Name kind() const = 0; - - /** - * Returns JNI error code JNI_ENOMEM if memory could not be allocated, - * and JNI_OK on success. - */ - virtual jint initialize() = 0; - - // In many heaps, there will be a need to perform some initialization activities - // after the Universe is fully formed, but before general heap allocation is allowed. - // This is the correct place to place such initialization methods. - virtual void post_initialize(); - - // Stop any onging concurrent work and prepare for exit. - virtual void stop() {} - - void initialize_reserved_region(HeapWord *start, HeapWord *end); - MemRegion reserved_region() const { return _reserved; } - address base() const { return (address)reserved_region().start(); } - - virtual size_t capacity() const = 0; - virtual size_t used() const = 0; - - // Return "true" if the part of the heap that allocates Java - // objects has reached the maximal committed limit that it can - // reach, without a garbage collection. - virtual bool is_maximal_no_gc() const = 0; - - // Support for java.lang.Runtime.maxMemory(): return the maximum amount of - // memory that the vm could make available for storing 'normal' java objects. - // This is based on the reserved address space, but should not include space - // that the vm uses internally for bookkeeping or temporary storage - // (e.g., in the case of the young gen, one of the survivor - // spaces). - virtual size_t max_capacity() const = 0; - - // Returns "TRUE" if "p" points into the reserved area of the heap. - bool is_in_reserved(const void* p) const { - return _reserved.contains(p); - } - - bool is_in_reserved_or_null(const void* p) const { - return p == NULL || is_in_reserved(p); - } - - // Returns "TRUE" iff "p" points into the committed areas of the heap. - // This method can be expensive so avoid using it in performance critical - // code. - virtual bool is_in(const void* p) const = 0; - - DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); }) - - // Let's define some terms: a "closed" subset of a heap is one that - // - // 1) contains all currently-allocated objects, and - // - // 2) is closed under reference: no object in the closed subset - // references one outside the closed subset. - // - // Membership in a heap's closed subset is useful for assertions. - // Clearly, the entire heap is a closed subset, so the default - // implementation is to use "is_in_reserved". But this may not be too - // liberal to perform useful checking. Also, the "is_in" predicate - // defines a closed subset, but may be too expensive, since "is_in" - // verifies that its argument points to an object head. The - // "closed_subset" method allows a heap to define an intermediate - // predicate, allowing more precise checking than "is_in_reserved" at - // lower cost than "is_in." - - // One important case is a heap composed of disjoint contiguous spaces, - // such as the Garbage-First collector. Such heaps have a convenient - // closed subset consisting of the allocated portions of those - // contiguous spaces. - - // Return "TRUE" iff the given pointer points into the heap's defined - // closed subset (which defaults to the entire heap). - virtual bool is_in_closed_subset(const void* p) const { - return is_in_reserved(p); - } - - bool is_in_closed_subset_or_null(const void* p) const { - return p == NULL || is_in_closed_subset(p); - } - - // An object is scavengable if its location may move during a scavenge. - // (A scavenge is a GC which is not a full GC.) - virtual bool is_scavengable(const void *p) = 0; - - void set_gc_cause(GCCause::Cause v) { - if (UsePerfData) { - _gc_lastcause = _gc_cause; - _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause)); - _perf_gc_cause->set_value(GCCause::to_string(v)); - } - _gc_cause = v; - } - GCCause::Cause gc_cause() { return _gc_cause; } - - // Number of threads currently working on GC tasks. - uint n_par_threads() { return _n_par_threads; } - - // May be overridden to set additional parallelism. - virtual void set_par_threads(uint t) { _n_par_threads = t; }; - - // General obj/array allocation facilities. - inline static oop obj_allocate(KlassHandle klass, int size, TRAPS); - inline static oop array_allocate(KlassHandle klass, int size, int length, TRAPS); - inline static oop array_allocate_nozero(KlassHandle klass, int size, int length, TRAPS); - - inline static void post_allocation_install_obj_klass(KlassHandle klass, - oop obj); - - // Raw memory allocation facilities - // The obj and array allocate methods are covers for these methods. - // mem_allocate() should never be - // called to allocate TLABs, only individual objects. - virtual HeapWord* mem_allocate(size_t size, - bool* gc_overhead_limit_was_exceeded) = 0; - - // Utilities for turning raw memory into filler objects. - // - // min_fill_size() is the smallest region that can be filled. - // fill_with_objects() can fill arbitrary-sized regions of the heap using - // multiple objects. fill_with_object() is for regions known to be smaller - // than the largest array of integers; it uses a single object to fill the - // region and has slightly less overhead. - static size_t min_fill_size() { - return size_t(align_object_size(oopDesc::header_size())); - } - - static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); - - static void fill_with_object(HeapWord* start, size_t words, bool zap = true); - static void fill_with_object(MemRegion region, bool zap = true) { - fill_with_object(region.start(), region.word_size(), zap); - } - static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { - fill_with_object(start, pointer_delta(end, start), zap); - } - - // Return the address "addr" aligned by "alignment_in_bytes" if such - // an address is below "end". Return NULL otherwise. - inline static HeapWord* align_allocation_or_fail(HeapWord* addr, - HeapWord* end, - unsigned short alignment_in_bytes); - - // Some heaps may offer a contiguous region for shared non-blocking - // allocation, via inlined code (by exporting the address of the top and - // end fields defining the extent of the contiguous allocation region.) - - // This function returns "true" iff the heap supports this kind of - // allocation. (Default is "no".) - virtual bool supports_inline_contig_alloc() const { - return false; - } - // These functions return the addresses of the fields that define the - // boundaries of the contiguous allocation area. (These fields should be - // physically near to one another.) - virtual HeapWord** top_addr() const { - guarantee(false, "inline contiguous allocation not supported"); - return NULL; - } - virtual HeapWord** end_addr() const { - guarantee(false, "inline contiguous allocation not supported"); - return NULL; - } - - // Some heaps may be in an unparseable state at certain times between - // collections. This may be necessary for efficient implementation of - // certain allocation-related activities. Calling this function before - // attempting to parse a heap ensures that the heap is in a parsable - // state (provided other concurrent activity does not introduce - // unparsability). It is normally expected, therefore, that this - // method is invoked with the world stopped. - // NOTE: if you override this method, make sure you call - // super::ensure_parsability so that the non-generational - // part of the work gets done. See implementation of - // CollectedHeap::ensure_parsability and, for instance, - // that of GenCollectedHeap::ensure_parsability(). - // The argument "retire_tlabs" controls whether existing TLABs - // are merely filled or also retired, thus preventing further - // allocation from them and necessitating allocation of new TLABs. - virtual void ensure_parsability(bool retire_tlabs); - - // Section on thread-local allocation buffers (TLABs) - // If the heap supports thread-local allocation buffers, it should override - // the following methods: - // Returns "true" iff the heap supports thread-local allocation buffers. - // The default is "no". - virtual bool supports_tlab_allocation() const = 0; - - // The amount of space available for thread-local allocation buffers. - virtual size_t tlab_capacity(Thread *thr) const = 0; - - // The amount of used space for thread-local allocation buffers for the given thread. - virtual size_t tlab_used(Thread *thr) const = 0; - - virtual size_t max_tlab_size() const; - - // An estimate of the maximum allocation that could be performed - // for thread-local allocation buffers without triggering any - // collection or expansion activity. - virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { - guarantee(false, "thread-local allocation buffers not supported"); - return 0; - } - - // Can a compiler initialize a new object without store barriers? - // This permission only extends from the creation of a new object - // via a TLAB up to the first subsequent safepoint. If such permission - // is granted for this heap type, the compiler promises to call - // defer_store_barrier() below on any slow path allocation of - // a new object for which such initializing store barriers will - // have been elided. - virtual bool can_elide_tlab_store_barriers() const = 0; - - // If a compiler is eliding store barriers for TLAB-allocated objects, - // there is probably a corresponding slow path which can produce - // an object allocated anywhere. The compiler's runtime support - // promises to call this function on such a slow-path-allocated - // object before performing initializations that have elided - // store barriers. Returns new_obj, or maybe a safer copy thereof. - virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj); - - // Answers whether an initializing store to a new object currently - // allocated at the given address doesn't need a store - // barrier. Returns "true" if it doesn't need an initializing - // store barrier; answers "false" if it does. - virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0; - - // If a compiler is eliding store barriers for TLAB-allocated objects, - // we will be informed of a slow-path allocation by a call - // to new_store_pre_barrier() above. Such a call precedes the - // initialization of the object itself, and no post-store-barriers will - // be issued. Some heap types require that the barrier strictly follows - // the initializing stores. (This is currently implemented by deferring the - // barrier until the next slow-path allocation or gc-related safepoint.) - // This interface answers whether a particular heap type needs the card - // mark to be thus strictly sequenced after the stores. - virtual bool card_mark_must_follow_store() const = 0; - - // If the CollectedHeap was asked to defer a store barrier above, - // this informs it to flush such a deferred store barrier to the - // remembered set. - virtual void flush_deferred_store_barrier(JavaThread* thread); - - // Perform a collection of the heap; intended for use in implementing - // "System.gc". This probably implies as full a collection as the - // "CollectedHeap" supports. - virtual void collect(GCCause::Cause cause) = 0; - - // Perform a full collection - virtual void do_full_collection(bool clear_all_soft_refs) = 0; - - // 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. - virtual void collect_as_vm_thread(GCCause::Cause cause); - - // Returns the barrier set for this heap - BarrierSet* barrier_set() { return _barrier_set; } - void set_barrier_set(BarrierSet* barrier_set); - - // Returns "true" iff there is a stop-world GC in progress. (I assume - // that it should answer "false" for the concurrent part of a concurrent - // collector -- dld). - bool is_gc_active() const { return _is_gc_active; } - - // Total number of GC collections (started) - unsigned int total_collections() const { return _total_collections; } - unsigned int total_full_collections() const { return _total_full_collections;} - - // Increment total number of GC collections (started) - // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 - void increment_total_collections(bool full = false) { - _total_collections++; - if (full) { - increment_total_full_collections(); - } - } - - void increment_total_full_collections() { _total_full_collections++; } - - // Return the AdaptiveSizePolicy for the heap. - virtual AdaptiveSizePolicy* size_policy() = 0; - - // Return the CollectorPolicy for the heap - virtual CollectorPolicy* collector_policy() const = 0; - - // Iterate over all objects, calling "cl.do_object" on each. - virtual void object_iterate(ObjectClosure* cl) = 0; - - // Similar to object_iterate() except iterates only - // over live objects. - virtual void safe_object_iterate(ObjectClosure* cl) = 0; - - // NOTE! There is no requirement that a collector implement these - // functions. - // - // 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 = 0; - - // 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. - virtual size_t block_size(const HeapWord* addr) const = 0; - - // Requires "addr" to be the start of a block, and returns "TRUE" iff - // the block is an object. - virtual bool block_is_obj(const HeapWord* addr) const = 0; - - // Returns the longest time (in ms) that has elapsed since the last - // time that any part of the heap was examined by a garbage collection. - virtual jlong millis_since_last_gc() = 0; - - // Perform any cleanup actions necessary before allowing a verification. - virtual void prepare_for_verify() = 0; - - // Generate any dumps preceding or following a full gc - void pre_full_gc_dump(GCTimer* timer); - void post_full_gc_dump(GCTimer* timer); - - VirtualSpaceSummary create_heap_space_summary(); - GCHeapSummary create_heap_summary(); - - MetaspaceSummary create_metaspace_summary(); - - // Print heap information on the given outputStream. - virtual void print_on(outputStream* st) const = 0; - // The default behavior is to call print_on() on tty. - virtual void print() const { - print_on(tty); - } - // Print more detailed heap information on the given - // outputStream. The default behavior is to call print_on(). It is - // up to each subclass to override it and add any additional output - // it needs. - virtual void print_extended_on(outputStream* st) const { - print_on(st); - } - - virtual void print_on_error(outputStream* st) const; - - // Print all GC threads (other than the VM thread) - // used by this heap. - virtual void print_gc_threads_on(outputStream* st) const = 0; - // The default behavior is to call print_gc_threads_on() on tty. - void print_gc_threads() { - print_gc_threads_on(tty); - } - // Iterator for all GC threads (other than VM thread) - virtual void gc_threads_do(ThreadClosure* tc) const = 0; - - // Print any relevant tracing info that flags imply. - // Default implementation does nothing. - virtual void print_tracing_info() const = 0; - - void print_heap_before_gc(); - void print_heap_after_gc(); - - // Registering and unregistering an nmethod (compiled code) with the heap. - // Override with specific mechanism for each specialized heap type. - virtual void register_nmethod(nmethod* nm); - virtual void unregister_nmethod(nmethod* nm); - - void trace_heap_before_gc(const GCTracer* gc_tracer); - void trace_heap_after_gc(const GCTracer* gc_tracer); - - // Heap verification - virtual void verify(bool silent, VerifyOption option) = 0; - - // Non product verification and debugging. -#ifndef PRODUCT - // Support for PromotionFailureALot. Return true if it's time to cause a - // promotion failure. The no-argument version uses - // this->_promotion_failure_alot_count as the counter. - inline bool promotion_should_fail(volatile size_t* count); - inline bool promotion_should_fail(); - - // Reset the PromotionFailureALot counters. Should be called at the end of a - // GC in which promotion failure occurred. - inline void reset_promotion_should_fail(volatile size_t* count); - inline void reset_promotion_should_fail(); -#endif // #ifndef PRODUCT - -#ifdef ASSERT - static int fired_fake_oom() { - return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); - } -#endif - - public: - // Copy the current allocation context statistics for the specified contexts. - // For each context in contexts, set the corresponding entries in the totals - // and accuracy arrays to the current values held by the statistics. Each - // array should be of length len. - // Returns true if there are more stats available. - virtual bool copy_allocation_context_stats(const jint* contexts, - jlong* totals, - jbyte* accuracy, - jint len) { - return false; - } - - /////////////// Unit tests /////////////// - - NOT_PRODUCT(static void test_is_in();) -}; - -// Class to set and reset the GC cause for a CollectedHeap. - -class GCCauseSetter : StackObj { - CollectedHeap* _heap; - GCCause::Cause _previous_cause; - public: - GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { - assert(SafepointSynchronize::is_at_safepoint(), - "This method manipulates heap state without locking"); - _heap = heap; - _previous_cause = _heap->gc_cause(); - _heap->set_gc_cause(cause); - } - - ~GCCauseSetter() { - assert(SafepointSynchronize::is_at_safepoint(), - "This method manipulates heap state without locking"); - _heap->set_gc_cause(_previous_cause); - } -}; - -#endif // SHARE_VM_GC_INTERFACE_COLLECTEDHEAP_HPP --- /dev/null 2015-03-18 17:10:38.111854831 +0100 +++ new/src/share/vm/gc/shared/collectedHeap.hpp 2015-05-12 11:56:38.886310984 +0200 @@ -0,0 +1,639 @@ +/* + * Copyright (c) 2001, 2015, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +#ifndef SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP +#define SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP + +#include "gc/shared/gcCause.hpp" +#include "gc/shared/gcWhen.hpp" +#include "memory/allocation.hpp" +#include "runtime/handles.hpp" +#include "runtime/perfData.hpp" +#include "runtime/safepoint.hpp" +#include "utilities/events.hpp" + +// A "CollectedHeap" is an implementation of a java heap for HotSpot. This +// is an abstract class: there may be many different kinds of heaps. This +// class defines the functions that a heap must implement, and contains +// infrastructure common to all heaps. + +class AdaptiveSizePolicy; +class BarrierSet; +class CollectorPolicy; +class GCHeapSummary; +class GCTimer; +class GCTracer; +class MetaspaceSummary; +class Thread; +class ThreadClosure; +class VirtualSpaceSummary; +class nmethod; + +class GCMessage : public FormatBuffer<1024> { + public: + bool is_before; + + public: + GCMessage() {} +}; + +class GCHeapLog : public EventLogBase { + private: + void log_heap(bool before); + + public: + GCHeapLog() : EventLogBase("GC Heap History") {} + + void log_heap_before() { + log_heap(true); + } + void log_heap_after() { + log_heap(false); + } +}; + +// +// CollectedHeap +// GenCollectedHeap +// G1CollectedHeap +// ParallelScavengeHeap +// +class CollectedHeap : public CHeapObj { + friend class VMStructs; + friend class IsGCActiveMark; // Block structured external access to _is_gc_active + + private: +#ifdef ASSERT + static int _fire_out_of_memory_count; +#endif + + // Used for filler objects (static, but initialized in ctor). + static size_t _filler_array_max_size; + + GCHeapLog* _gc_heap_log; + + // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 is being used + bool _defer_initial_card_mark; + + MemRegion _reserved; + + protected: + BarrierSet* _barrier_set; + bool _is_gc_active; + uint _n_par_threads; + + unsigned int _total_collections; // ... started + unsigned int _total_full_collections; // ... started + NOT_PRODUCT(volatile size_t _promotion_failure_alot_count;) + NOT_PRODUCT(volatile size_t _promotion_failure_alot_gc_number;) + + // Reason for current garbage collection. Should be set to + // a value reflecting no collection between collections. + GCCause::Cause _gc_cause; + GCCause::Cause _gc_lastcause; + PerfStringVariable* _perf_gc_cause; + PerfStringVariable* _perf_gc_lastcause; + + // Constructor + CollectedHeap(); + + // Do common initializations that must follow instance construction, + // for example, those needing virtual calls. + // This code could perhaps be moved into initialize() but would + // be slightly more awkward because we want the latter to be a + // pure virtual. + void pre_initialize(); + + // Create a new tlab. All TLAB allocations must go through this. + virtual HeapWord* allocate_new_tlab(size_t size); + + // Accumulate statistics on all tlabs. + virtual void accumulate_statistics_all_tlabs(); + + // Reinitialize tlabs before resuming mutators. + virtual void resize_all_tlabs(); + + // Allocate from the current thread's TLAB, with broken-out slow path. + inline static HeapWord* allocate_from_tlab(KlassHandle klass, Thread* thread, size_t size); + static HeapWord* allocate_from_tlab_slow(KlassHandle klass, Thread* thread, size_t size); + + // Allocate an uninitialized block of the given size, or returns NULL if + // this is impossible. + inline static HeapWord* common_mem_allocate_noinit(KlassHandle klass, size_t size, TRAPS); + + // Like allocate_init, but the block returned by a successful allocation + // is guaranteed initialized to zeros. + inline static HeapWord* common_mem_allocate_init(KlassHandle klass, size_t size, TRAPS); + + // Helper functions for (VM) allocation. + inline static void post_allocation_setup_common(KlassHandle klass, HeapWord* obj); + inline static void post_allocation_setup_no_klass_install(KlassHandle klass, + HeapWord* objPtr); + + inline static void post_allocation_setup_obj(KlassHandle klass, HeapWord* obj, int size); + + inline static void post_allocation_setup_array(KlassHandle klass, + HeapWord* obj, int length); + + // Clears an allocated object. + inline static void init_obj(HeapWord* obj, size_t size); + + // Filler object utilities. + static inline size_t filler_array_hdr_size(); + static inline size_t filler_array_min_size(); + + DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);) + DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);) + + // Fill with a single array; caller must ensure filler_array_min_size() <= + // words <= filler_array_max_size(). + static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true); + + // Fill with a single object (either an int array or a java.lang.Object). + static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true); + + virtual void trace_heap(GCWhen::Type when, const GCTracer* tracer); + + // Verification functions + virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size) + PRODUCT_RETURN; + virtual void check_for_non_bad_heap_word_value(HeapWord* addr, size_t size) + PRODUCT_RETURN; + debug_only(static void check_for_valid_allocation_state();) + + public: + enum Name { + GenCollectedHeap, + ParallelScavengeHeap, + G1CollectedHeap + }; + + static inline size_t filler_array_max_size() { + return _filler_array_max_size; + } + + virtual Name kind() const = 0; + + /** + * Returns JNI error code JNI_ENOMEM if memory could not be allocated, + * and JNI_OK on success. + */ + virtual jint initialize() = 0; + + // In many heaps, there will be a need to perform some initialization activities + // after the Universe is fully formed, but before general heap allocation is allowed. + // This is the correct place to place such initialization methods. + virtual void post_initialize(); + + // Stop any onging concurrent work and prepare for exit. + virtual void stop() {} + + void initialize_reserved_region(HeapWord *start, HeapWord *end); + MemRegion reserved_region() const { return _reserved; } + address base() const { return (address)reserved_region().start(); } + + virtual size_t capacity() const = 0; + virtual size_t used() const = 0; + + // Return "true" if the part of the heap that allocates Java + // objects has reached the maximal committed limit that it can + // reach, without a garbage collection. + virtual bool is_maximal_no_gc() const = 0; + + // Support for java.lang.Runtime.maxMemory(): return the maximum amount of + // memory that the vm could make available for storing 'normal' java objects. + // This is based on the reserved address space, but should not include space + // that the vm uses internally for bookkeeping or temporary storage + // (e.g., in the case of the young gen, one of the survivor + // spaces). + virtual size_t max_capacity() const = 0; + + // Returns "TRUE" if "p" points into the reserved area of the heap. + bool is_in_reserved(const void* p) const { + return _reserved.contains(p); + } + + bool is_in_reserved_or_null(const void* p) const { + return p == NULL || is_in_reserved(p); + } + + // Returns "TRUE" iff "p" points into the committed areas of the heap. + // This method can be expensive so avoid using it in performance critical + // code. + virtual bool is_in(const void* p) const = 0; + + DEBUG_ONLY(bool is_in_or_null(const void* p) const { return p == NULL || is_in(p); }) + + // Let's define some terms: a "closed" subset of a heap is one that + // + // 1) contains all currently-allocated objects, and + // + // 2) is closed under reference: no object in the closed subset + // references one outside the closed subset. + // + // Membership in a heap's closed subset is useful for assertions. + // Clearly, the entire heap is a closed subset, so the default + // implementation is to use "is_in_reserved". But this may not be too + // liberal to perform useful checking. Also, the "is_in" predicate + // defines a closed subset, but may be too expensive, since "is_in" + // verifies that its argument points to an object head. The + // "closed_subset" method allows a heap to define an intermediate + // predicate, allowing more precise checking than "is_in_reserved" at + // lower cost than "is_in." + + // One important case is a heap composed of disjoint contiguous spaces, + // such as the Garbage-First collector. Such heaps have a convenient + // closed subset consisting of the allocated portions of those + // contiguous spaces. + + // Return "TRUE" iff the given pointer points into the heap's defined + // closed subset (which defaults to the entire heap). + virtual bool is_in_closed_subset(const void* p) const { + return is_in_reserved(p); + } + + bool is_in_closed_subset_or_null(const void* p) const { + return p == NULL || is_in_closed_subset(p); + } + + // An object is scavengable if its location may move during a scavenge. + // (A scavenge is a GC which is not a full GC.) + virtual bool is_scavengable(const void *p) = 0; + + void set_gc_cause(GCCause::Cause v) { + if (UsePerfData) { + _gc_lastcause = _gc_cause; + _perf_gc_lastcause->set_value(GCCause::to_string(_gc_lastcause)); + _perf_gc_cause->set_value(GCCause::to_string(v)); + } + _gc_cause = v; + } + GCCause::Cause gc_cause() { return _gc_cause; } + + // Number of threads currently working on GC tasks. + uint n_par_threads() { return _n_par_threads; } + + // May be overridden to set additional parallelism. + virtual void set_par_threads(uint t) { _n_par_threads = t; }; + + // General obj/array allocation facilities. + inline static oop obj_allocate(KlassHandle klass, int size, TRAPS); + inline static oop array_allocate(KlassHandle klass, int size, int length, TRAPS); + inline static oop array_allocate_nozero(KlassHandle klass, int size, int length, TRAPS); + + inline static void post_allocation_install_obj_klass(KlassHandle klass, + oop obj); + + // Raw memory allocation facilities + // The obj and array allocate methods are covers for these methods. + // mem_allocate() should never be + // called to allocate TLABs, only individual objects. + virtual HeapWord* mem_allocate(size_t size, + bool* gc_overhead_limit_was_exceeded) = 0; + + // Utilities for turning raw memory into filler objects. + // + // min_fill_size() is the smallest region that can be filled. + // fill_with_objects() can fill arbitrary-sized regions of the heap using + // multiple objects. fill_with_object() is for regions known to be smaller + // than the largest array of integers; it uses a single object to fill the + // region and has slightly less overhead. + static size_t min_fill_size() { + return size_t(align_object_size(oopDesc::header_size())); + } + + static void fill_with_objects(HeapWord* start, size_t words, bool zap = true); + + static void fill_with_object(HeapWord* start, size_t words, bool zap = true); + static void fill_with_object(MemRegion region, bool zap = true) { + fill_with_object(region.start(), region.word_size(), zap); + } + static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) { + fill_with_object(start, pointer_delta(end, start), zap); + } + + // Return the address "addr" aligned by "alignment_in_bytes" if such + // an address is below "end". Return NULL otherwise. + inline static HeapWord* align_allocation_or_fail(HeapWord* addr, + HeapWord* end, + unsigned short alignment_in_bytes); + + // Some heaps may offer a contiguous region for shared non-blocking + // allocation, via inlined code (by exporting the address of the top and + // end fields defining the extent of the contiguous allocation region.) + + // This function returns "true" iff the heap supports this kind of + // allocation. (Default is "no".) + virtual bool supports_inline_contig_alloc() const { + return false; + } + // These functions return the addresses of the fields that define the + // boundaries of the contiguous allocation area. (These fields should be + // physically near to one another.) + virtual HeapWord** top_addr() const { + guarantee(false, "inline contiguous allocation not supported"); + return NULL; + } + virtual HeapWord** end_addr() const { + guarantee(false, "inline contiguous allocation not supported"); + return NULL; + } + + // Some heaps may be in an unparseable state at certain times between + // collections. This may be necessary for efficient implementation of + // certain allocation-related activities. Calling this function before + // attempting to parse a heap ensures that the heap is in a parsable + // state (provided other concurrent activity does not introduce + // unparsability). It is normally expected, therefore, that this + // method is invoked with the world stopped. + // NOTE: if you override this method, make sure you call + // super::ensure_parsability so that the non-generational + // part of the work gets done. See implementation of + // CollectedHeap::ensure_parsability and, for instance, + // that of GenCollectedHeap::ensure_parsability(). + // The argument "retire_tlabs" controls whether existing TLABs + // are merely filled or also retired, thus preventing further + // allocation from them and necessitating allocation of new TLABs. + virtual void ensure_parsability(bool retire_tlabs); + + // Section on thread-local allocation buffers (TLABs) + // If the heap supports thread-local allocation buffers, it should override + // the following methods: + // Returns "true" iff the heap supports thread-local allocation buffers. + // The default is "no". + virtual bool supports_tlab_allocation() const = 0; + + // The amount of space available for thread-local allocation buffers. + virtual size_t tlab_capacity(Thread *thr) const = 0; + + // The amount of used space for thread-local allocation buffers for the given thread. + virtual size_t tlab_used(Thread *thr) const = 0; + + virtual size_t max_tlab_size() const; + + // An estimate of the maximum allocation that could be performed + // for thread-local allocation buffers without triggering any + // collection or expansion activity. + virtual size_t unsafe_max_tlab_alloc(Thread *thr) const { + guarantee(false, "thread-local allocation buffers not supported"); + return 0; + } + + // Can a compiler initialize a new object without store barriers? + // This permission only extends from the creation of a new object + // via a TLAB up to the first subsequent safepoint. If such permission + // is granted for this heap type, the compiler promises to call + // defer_store_barrier() below on any slow path allocation of + // a new object for which such initializing store barriers will + // have been elided. + virtual bool can_elide_tlab_store_barriers() const = 0; + + // If a compiler is eliding store barriers for TLAB-allocated objects, + // there is probably a corresponding slow path which can produce + // an object allocated anywhere. The compiler's runtime support + // promises to call this function on such a slow-path-allocated + // object before performing initializations that have elided + // store barriers. Returns new_obj, or maybe a safer copy thereof. + virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj); + + // Answers whether an initializing store to a new object currently + // allocated at the given address doesn't need a store + // barrier. Returns "true" if it doesn't need an initializing + // store barrier; answers "false" if it does. + virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0; + + // If a compiler is eliding store barriers for TLAB-allocated objects, + // we will be informed of a slow-path allocation by a call + // to new_store_pre_barrier() above. Such a call precedes the + // initialization of the object itself, and no post-store-barriers will + // be issued. Some heap types require that the barrier strictly follows + // the initializing stores. (This is currently implemented by deferring the + // barrier until the next slow-path allocation or gc-related safepoint.) + // This interface answers whether a particular heap type needs the card + // mark to be thus strictly sequenced after the stores. + virtual bool card_mark_must_follow_store() const = 0; + + // If the CollectedHeap was asked to defer a store barrier above, + // this informs it to flush such a deferred store barrier to the + // remembered set. + virtual void flush_deferred_store_barrier(JavaThread* thread); + + // Perform a collection of the heap; intended for use in implementing + // "System.gc". This probably implies as full a collection as the + // "CollectedHeap" supports. + virtual void collect(GCCause::Cause cause) = 0; + + // Perform a full collection + virtual void do_full_collection(bool clear_all_soft_refs) = 0; + + // 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. + virtual void collect_as_vm_thread(GCCause::Cause cause); + + // Returns the barrier set for this heap + BarrierSet* barrier_set() { return _barrier_set; } + void set_barrier_set(BarrierSet* barrier_set); + + // Returns "true" iff there is a stop-world GC in progress. (I assume + // that it should answer "false" for the concurrent part of a concurrent + // collector -- dld). + bool is_gc_active() const { return _is_gc_active; } + + // Total number of GC collections (started) + unsigned int total_collections() const { return _total_collections; } + unsigned int total_full_collections() const { return _total_full_collections;} + + // Increment total number of GC collections (started) + // Should be protected but used by PSMarkSweep - cleanup for 1.4.2 + void increment_total_collections(bool full = false) { + _total_collections++; + if (full) { + increment_total_full_collections(); + } + } + + void increment_total_full_collections() { _total_full_collections++; } + + // Return the AdaptiveSizePolicy for the heap. + virtual AdaptiveSizePolicy* size_policy() = 0; + + // Return the CollectorPolicy for the heap + virtual CollectorPolicy* collector_policy() const = 0; + + // Iterate over all objects, calling "cl.do_object" on each. + virtual void object_iterate(ObjectClosure* cl) = 0; + + // Similar to object_iterate() except iterates only + // over live objects. + virtual void safe_object_iterate(ObjectClosure* cl) = 0; + + // NOTE! There is no requirement that a collector implement these + // functions. + // + // 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 = 0; + + // 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. + virtual size_t block_size(const HeapWord* addr) const = 0; + + // Requires "addr" to be the start of a block, and returns "TRUE" iff + // the block is an object. + virtual bool block_is_obj(const HeapWord* addr) const = 0; + + // Returns the longest time (in ms) that has elapsed since the last + // time that any part of the heap was examined by a garbage collection. + virtual jlong millis_since_last_gc() = 0; + + // Perform any cleanup actions necessary before allowing a verification. + virtual void prepare_for_verify() = 0; + + // Generate any dumps preceding or following a full gc + void pre_full_gc_dump(GCTimer* timer); + void post_full_gc_dump(GCTimer* timer); + + VirtualSpaceSummary create_heap_space_summary(); + GCHeapSummary create_heap_summary(); + + MetaspaceSummary create_metaspace_summary(); + + // Print heap information on the given outputStream. + virtual void print_on(outputStream* st) const = 0; + // The default behavior is to call print_on() on tty. + virtual void print() const { + print_on(tty); + } + // Print more detailed heap information on the given + // outputStream. The default behavior is to call print_on(). It is + // up to each subclass to override it and add any additional output + // it needs. + virtual void print_extended_on(outputStream* st) const { + print_on(st); + } + + virtual void print_on_error(outputStream* st) const; + + // Print all GC threads (other than the VM thread) + // used by this heap. + virtual void print_gc_threads_on(outputStream* st) const = 0; + // The default behavior is to call print_gc_threads_on() on tty. + void print_gc_threads() { + print_gc_threads_on(tty); + } + // Iterator for all GC threads (other than VM thread) + virtual void gc_threads_do(ThreadClosure* tc) const = 0; + + // Print any relevant tracing info that flags imply. + // Default implementation does nothing. + virtual void print_tracing_info() const = 0; + + void print_heap_before_gc(); + void print_heap_after_gc(); + + // Registering and unregistering an nmethod (compiled code) with the heap. + // Override with specific mechanism for each specialized heap type. + virtual void register_nmethod(nmethod* nm); + virtual void unregister_nmethod(nmethod* nm); + + void trace_heap_before_gc(const GCTracer* gc_tracer); + void trace_heap_after_gc(const GCTracer* gc_tracer); + + // Heap verification + virtual void verify(bool silent, VerifyOption option) = 0; + + // Non product verification and debugging. +#ifndef PRODUCT + // Support for PromotionFailureALot. Return true if it's time to cause a + // promotion failure. The no-argument version uses + // this->_promotion_failure_alot_count as the counter. + inline bool promotion_should_fail(volatile size_t* count); + inline bool promotion_should_fail(); + + // Reset the PromotionFailureALot counters. Should be called at the end of a + // GC in which promotion failure occurred. + inline void reset_promotion_should_fail(volatile size_t* count); + inline void reset_promotion_should_fail(); +#endif // #ifndef PRODUCT + +#ifdef ASSERT + static int fired_fake_oom() { + return (CIFireOOMAt > 1 && _fire_out_of_memory_count >= CIFireOOMAt); + } +#endif + + public: + // Copy the current allocation context statistics for the specified contexts. + // For each context in contexts, set the corresponding entries in the totals + // and accuracy arrays to the current values held by the statistics. Each + // array should be of length len. + // Returns true if there are more stats available. + virtual bool copy_allocation_context_stats(const jint* contexts, + jlong* totals, + jbyte* accuracy, + jint len) { + return false; + } + + /////////////// Unit tests /////////////// + + NOT_PRODUCT(static void test_is_in();) +}; + +// Class to set and reset the GC cause for a CollectedHeap. + +class GCCauseSetter : StackObj { + CollectedHeap* _heap; + GCCause::Cause _previous_cause; + public: + GCCauseSetter(CollectedHeap* heap, GCCause::Cause cause) { + assert(SafepointSynchronize::is_at_safepoint(), + "This method manipulates heap state without locking"); + _heap = heap; + _previous_cause = _heap->gc_cause(); + _heap->set_gc_cause(cause); + } + + ~GCCauseSetter() { + assert(SafepointSynchronize::is_at_safepoint(), + "This method manipulates heap state without locking"); + _heap->set_gc_cause(_previous_cause); + } +}; + +#endif // SHARE_VM_GC_SHARED_COLLECTEDHEAP_HPP