/* * Copyright (c) 2005, 2010, 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. * */ // The following class hierarchy represents // a set of operations (VM_Operation) related to GC. // // VM_Operation // VM_GC_Operation // VM_GC_HeapInspection // VM_GenCollectForAllocation // VM_GenCollectFull // VM_GenCollectFullConcurrent // VM_ParallelGCFailedAllocation // VM_ParallelGCFailedPermanentAllocation // VM_ParallelGCSystemGC // VM_GC_Operation // - implements methods common to all classes in the hierarchy: // prevents multiple gc requests and manages lock on heap; // // VM_GC_HeapInspection // - prints class histogram on SIGBREAK if PrintClassHistogram // is specified; and also the attach "inspectheap" operation // // VM_GenCollectForAllocation // VM_GenCollectForPermanentAllocation // VM_ParallelGCFailedAllocation // VM_ParallelGCFailedPermanentAllocation // - this operation is invoked when allocation is failed; // operation performs garbage collection and tries to // allocate afterwards; // // VM_GenCollectFull // VM_GenCollectFullConcurrent // VM_ParallelGCSystemGC // - these operations preform full collection of heaps of // different kind // class VM_GC_Operation: public VM_Operation { protected: BasicLock _pending_list_basic_lock; // for refs pending list notification (PLL) unsigned int _gc_count_before; // gc count before acquiring PLL unsigned int _full_gc_count_before; // full gc count before acquiring PLL bool _full; // whether a "full" collection bool _prologue_succeeded; // whether doit_prologue succeeded GCCause::Cause _gc_cause; // the putative cause for this gc op bool _gc_locked; // will be set if gc was locked virtual bool skip_operation() const; // java.lang.ref.Reference support void acquire_pending_list_lock(); void release_and_notify_pending_list_lock(); public: VM_GC_Operation(unsigned int gc_count_before, unsigned int full_gc_count_before = 0, bool full = false) { _full = full; _prologue_succeeded = false; _gc_count_before = gc_count_before; // A subclass constructor will likely overwrite the following _gc_cause = GCCause::_no_cause_specified; _gc_locked = false; if (full) { _full_gc_count_before = full_gc_count_before; } // In ParallelScavengeHeap::mem_allocate() collections can be // executed within a loop and _all_soft_refs_clear can be set // true after they have been cleared by a collection and another // collection started so that _all_soft_refs_clear can be true // when this collection is started. Don't assert that // _all_soft_refs_clear have to be false here even though // mutators have run. Soft refs will be cleared again in this // collection. } ~VM_GC_Operation() { CollectedHeap* ch = Universe::heap(); ch->collector_policy()->set_all_soft_refs_clear(false); } // Acquire the reference synchronization lock virtual bool doit_prologue(); // Do notifyAll (if needed) and release held lock virtual void doit_epilogue(); virtual bool allow_nested_vm_operations() const { return true; } bool prologue_succeeded() const { return _prologue_succeeded; } void set_gc_locked() { _gc_locked = true; } bool gc_locked() const { return _gc_locked; } static void notify_gc_begin(bool full = false); static void notify_gc_end(); }; class VM_GC_HeapInspection: public VM_GC_Operation { private: outputStream* _out; bool _full_gc; bool _need_prologue; public: VM_GC_HeapInspection(outputStream* out, bool request_full_gc, bool need_prologue) : VM_GC_Operation(0 /* total collections, dummy, ignored */, 0 /* total full collections, dummy, ignored */, request_full_gc) { _out = out; _full_gc = request_full_gc; _need_prologue = need_prologue; } ~VM_GC_HeapInspection() {} virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; } virtual bool skip_operation() const; virtual bool doit_prologue(); virtual void doit(); }; class VM_GenCollectForAllocation: public VM_GC_Operation { private: HeapWord* _res; size_t _size; // size of object to be allocated. bool _tlab; // alloc is of a tlab. public: VM_GenCollectForAllocation(size_t size, bool tlab, unsigned int gc_count_before) : VM_GC_Operation(gc_count_before), _size(size), _tlab(tlab) { _res = NULL; } ~VM_GenCollectForAllocation() {} virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; } virtual void doit(); HeapWord* result() const { return _res; } }; // VM operation to invoke a collection of the heap as a // GenCollectedHeap heap. class VM_GenCollectFull: public VM_GC_Operation { private: int _max_level; public: VM_GenCollectFull(unsigned int gc_count_before, unsigned int full_gc_count_before, GCCause::Cause gc_cause, int max_level) : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */), _max_level(max_level) { _gc_cause = gc_cause; } ~VM_GenCollectFull() {} virtual VMOp_Type type() const { return VMOp_GenCollectFull; } virtual void doit(); }; class VM_GenCollectForPermanentAllocation: public VM_GC_Operation { private: HeapWord* _res; size_t _size; // size of object to be allocated public: VM_GenCollectForPermanentAllocation(size_t size, unsigned int gc_count_before, unsigned int full_gc_count_before, GCCause::Cause gc_cause) : VM_GC_Operation(gc_count_before, full_gc_count_before, true), _size(size) { _res = NULL; _gc_cause = gc_cause; } ~VM_GenCollectForPermanentAllocation() {} virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; } virtual void doit(); HeapWord* result() const { return _res; } };