truffle: src/share/vm/gc_interface/collectedHeap.hpp comparison

comparison src/share/vm/gc_interface/collectedHeap.hpp @ 0:a61af66fc99e jdk7-b24

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

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+:a61af66fc99e
+/*
+* 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);
+}
+};

Mercurial > hg > truffle

comparison src/share/vm/gc_interface/collectedHeap.hpp @ 0:a61af66fc99e jdk7-b24