Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * 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;

     _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; }

 };