| /* |
| * Copyright (c) 2001, 2016, 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 CollectedHeap; |
| |
| class GCHeapLog : public EventLogBase<GCMessage> { |
| private: |
| void log_heap(CollectedHeap* heap, bool before); |
| |
| public: |
| GCHeapLog() : EventLogBase<GCMessage>("GC Heap History") {} |
| |
| void log_heap_before(CollectedHeap* heap) { |
| log_heap(heap, true); |
| } |
| void log_heap_after(CollectedHeap* heap) { |
| log_heap(heap, false); |
| } |
| }; |
| |
| // |
| // CollectedHeap |
| // GenCollectedHeap |
| // G1CollectedHeap |
| // ParallelScavengeHeap |
| // |
| class CollectedHeap : public CHeapObj<mtInternal> { |
| friend class VMStructs; |
| friend class JVMCIVMStructs; |
| friend class IsGCActiveMark; // Block structured external access to _is_gc_active |
| |
| private: |
| #ifdef ASSERT |
| static int _fire_out_of_memory_count; |
| #endif |
| |
| GCHeapLog* _gc_heap_log; |
| |
| // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 |
| // or INCLUDE_JVMCI is being used |
| bool _defer_initial_card_mark; |
| |
| MemRegion _reserved; |
| |
| protected: |
| BarrierSet* _barrier_set; |
| bool _is_gc_active; |
| |
| // Used for filler objects (static, but initialized in ctor). |
| static size_t _filler_array_max_size; |
| |
| 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; |
| |
| virtual const char* name() 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; } |
| |
| // 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); |
| |
| // Should return true if the reference pending list lock is |
| // acquired from non-Java threads, such as a concurrent GC thread. |
| virtual bool needs_reference_pending_list_locker_thread() const { |
| return false; |
| } |
| |
| // 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 |
| private: |
| void full_gc_dump(GCTimer* timer, bool before); |
| public: |
| 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(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 |