Mercurial > hg > truffle
diff src/share/vm/gc_interface/collectedHeap.hpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_interface/collectedHeap.hpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,539 @@ +/* + * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. + * + */ + +// 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 BarrierSet; +class ThreadClosure; +class AdaptiveSizePolicy; +class Thread; + +// +// CollectedHeap +// SharedHeap +// GenCollectedHeap +// G1CollectedHeap +// ParallelScavengeHeap +// +class CollectedHeap : public CHeapObj { + friend class VMStructs; + friend class IsGCActiveMark; // Block structured external access to _is_gc_active + +#ifdef ASSERT + static int _fire_out_of_memory_count; +#endif + + protected: + MemRegion _reserved; + BarrierSet* _barrier_set; + bool _is_gc_active; + unsigned int _total_collections; // ... started + unsigned int _total_full_collections; // ... started + size_t _max_heap_capacity; + 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(); + + // Create a new tlab + virtual HeapWord* allocate_new_tlab(size_t size); + + // Fix up tlabs to make the heap well-formed again, + // optionally retiring the tlabs. + virtual void fill_all_tlabs(bool retire); + + // Accumulate statistics on all tlabs. + virtual void accumulate_statistics_all_tlabs(); + + // Reinitialize tlabs before resuming mutators. + virtual void resize_all_tlabs(); + + debug_only(static void check_for_valid_allocation_state();) + + protected: + // Allocate from the current thread's TLAB, with broken-out slow path. + inline static HeapWord* allocate_from_tlab(Thread* thread, size_t size); + static HeapWord* allocate_from_tlab_slow(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(size_t size, bool is_noref, TRAPS); + + // Like allocate_init, but the block returned by a successful allocation + // is guaranteed initialized to zeros. + inline static HeapWord* common_mem_allocate_init(size_t size, bool is_noref, TRAPS); + + // Same as common_mem version, except memory is allocated in the permanent area + // If there is no permanent area, revert to common_mem_allocate_noinit + inline static HeapWord* common_permanent_mem_allocate_noinit(size_t size, TRAPS); + + // Same as common_mem version, except memory is allocated in the permanent area + // If there is no permanent area, revert to common_mem_allocate_init + inline static HeapWord* common_permanent_mem_allocate_init(size_t size, TRAPS); + + // Helper functions for (VM) allocation. + inline static void post_allocation_setup_common(KlassHandle klass, + HeapWord* obj, size_t size); + inline static void post_allocation_setup_no_klass_install(KlassHandle klass, + HeapWord* objPtr, + size_t size); + + inline static void post_allocation_setup_obj(KlassHandle klass, + HeapWord* obj, size_t size); + + inline static void post_allocation_setup_array(KlassHandle klass, + HeapWord* obj, size_t size, + int length); + + // Clears an allocated object. + inline static void init_obj(HeapWord* obj, size_t size); + + // 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; + + public: + enum Name { + Abstract, + SharedHeap, + GenCollectedHeap, + ParallelScavengeHeap, + G1CollectedHeap + }; + + virtual CollectedHeap::Name kind() const { return CollectedHeap::Abstract; } + + /** + * 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() = 0; + + MemRegion reserved_region() const { return _reserved; } + + // Return the number of bytes currently reserved, committed, and used, + // respectively, for holding objects. + size_t reserved_obj_bytes() const { return _reserved.byte_size(); } + + // Future cleanup here. The following functions should specify bytes or + // heapwords as part of their signature. + 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; + + virtual size_t permanent_capacity() const = 0; + virtual size_t permanent_used() 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., + // perm gen space or, 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" if "p" points to the head of an allocated object in the + // heap. Since this method can be expensive in general, we restrict its + // use to assertion checking only. + virtual bool is_in(const void* p) const = 0; + + 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); + } + + // Returns "TRUE" if "p" is allocated as "permanent" data. + // If the heap does not use "permanent" data, returns the same + // value is_in_reserved() would return. + // NOTE: this actually returns true if "p" is in reserved space + // for the space not that it is actually allocated (i.e. in committed + // space). If you need the more conservative answer use is_permanent(). + virtual bool is_in_permanent(const void *p) const = 0; + + // Returns "TRUE" if "p" is in the committed area of "permanent" data. + // If the heap does not use "permanent" data, returns the same + // value is_in() would return. + virtual bool is_permanent(const void *p) const = 0; + + bool is_in_permanent_or_null(const void *p) const { + return p == NULL || is_in_permanent(p); + } + + // Returns "TRUE" if "p" is a method oop in the + // current heap, with high probability. This predicate + // is not stable, in general. + bool is_valid_method(oop p) const; + + 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; } + + // Preload classes into the shared portion of the heap, and then dump + // that data to a file so that it can be loaded directly by another + // VM (then terminate). + virtual void preload_and_dump(TRAPS) { ShouldNotReachHere(); } + + // 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 large_typearray_allocate(KlassHandle klass, int size, int length, TRAPS); + + // Special obj/array allocation facilities. + // Some heaps may want to manage "permanent" data uniquely. These default + // to the general routines if the heap does not support such handling. + inline static oop permanent_obj_allocate(KlassHandle klass, int size, TRAPS); + // permanent_obj_allocate_no_klass_install() does not do the installation of + // the klass pointer in the newly created object (as permanent_obj_allocate() + // above does). This allows for a delay in the installation of the klass + // pointer that is needed during the create of klassKlass's. The + // method post_allocation_install_obj_klass() is used to install the + // klass pointer. + inline static oop permanent_obj_allocate_no_klass_install(KlassHandle klass, + int size, + TRAPS); + inline static void post_allocation_install_obj_klass(KlassHandle klass, + oop obj, + int size); + inline static oop permanent_array_allocate(KlassHandle klass, int size, int length, TRAPS); + + // Raw memory allocation facilities + // The obj and array allocate methods are covers for these methods. + // The permanent allocation method should default to mem_allocate if + // permanent memory isn't supported. + virtual HeapWord* mem_allocate(size_t size, + bool is_noref, + bool is_tlab, + bool* gc_overhead_limit_was_exceeded) = 0; + virtual HeapWord* permanent_mem_allocate(size_t size) = 0; + + // The boundary between a "large" and "small" array of primitives, in words. + virtual size_t large_typearray_limit() = 0; + + // 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); + + // Return an estimate of the maximum allocation that could be performed + // without triggering any collection or expansion activity. In a + // generational collector, for example, this is probably the largest + // allocation that could be supported (without expansion) in the youngest + // generation. It is "unsafe" because no locks are taken; the result + // should be treated as an approximation, not a guarantee, for use in + // heuristic resizing decisions. + virtual size_t unsafe_max_alloc() = 0; + + // 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 { + return false; + } + // The amount of space available for thread-local allocation buffers. + virtual size_t tlab_capacity(Thread *thr) const { + guarantee(false, "thread-local allocation buffers not supported"); + return 0; + } + // 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. + virtual bool can_elide_tlab_store_barriers() const { + guarantee(kind() < CollectedHeap::G1CollectedHeap, "else change or refactor this"); + return true; + } + // 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_barrier(oop new_obj); + + // Can a compiler elide a store barrier when it writes + // a permanent oop into the heap? Applies when the compiler + // is storing x to the heap, where x->is_perm() is true. + virtual bool can_elide_permanent_oop_store_barriers() const; + + // Does this heap support heap inspection (+PrintClassHistogram?) + virtual bool supports_heap_inspection() const { + return false; // Until RFE 5023697 is implemented + } + + // 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; + + // 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) = 0; + + // Returns the barrier set for this heap + BarrierSet* barrier_set() { return _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; + + // Iterate over all the ref-containing fields of all objects, calling + // "cl.do_oop" on each. This includes objects in permanent memory. + virtual void oop_iterate(OopClosure* cl) = 0; + + // Iterate over all objects, calling "cl.do_object" on each. + // This includes objects in permanent memory. + virtual void object_iterate(ObjectClosure* cl) = 0; + + // Behaves the same as oop_iterate, except only traverses + // interior pointers contained in permanent memory. If there + // is no permanent memory, does nothing. + virtual void permanent_oop_iterate(OopClosure* cl) = 0; + + // Behaves the same as object_iterate, except only traverses + // object contained in permanent memory. If there is no + // permanent memory, does nothing. + virtual void permanent_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; + + virtual void print() const = 0; + virtual void print_on(outputStream* st) const = 0; + + // Print all GC threads (other than the VM thread) + // used by this heap. + virtual void print_gc_threads_on(outputStream* st) const = 0; + 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; + + // Heap verification + virtual void verify(bool allow_dirty, bool silent) = 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 ocurred. + 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 +}; + +// 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); + } +};