1 /*
   2  * Copyright (c) 2005, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
  26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
  27 
  28 #include "memory/heapInspection.hpp"
  29 #include "runtime/handles.hpp"
  30 #include "runtime/jniHandles.hpp"
  31 #include "runtime/synchronizer.hpp"
  32 #include "runtime/vm_operations.hpp"
  33 #include "prims/jvmtiExport.hpp"
  34 
  35 // The following class hierarchy represents
  36 // a set of operations (VM_Operation) related to GC.
  37 //
  38 //  VM_Operation
  39 //      VM_GC_Operation
  40 //          VM_GC_HeapInspection
  41 //          VM_GenCollectForAllocation
  42 //          VM_GenCollectFull
  43 //          VM_GenCollectFullConcurrent
  44 //          VM_ParallelGCFailedAllocation
  45 //          VM_ParallelGCFailedPermanentAllocation
  46 //          VM_ParallelGCSystemGC
  47 //  VM_GC_Operation
  48 //   - implements methods common to all classes in the hierarchy:
  49 //     prevents multiple gc requests and manages lock on heap;
  50 //
  51 //  VM_GC_HeapInspection
  52 //   - prints class histogram on SIGBREAK if PrintClassHistogram
  53 //     is specified; and also the attach "inspectheap" operation
  54 //
  55 //  VM_GenCollectForAllocation
  56 //  VM_GenCollectForPermanentAllocation
  57 //  VM_ParallelGCFailedAllocation
  58 //  VM_ParallelGCFailedPermanentAllocation
  59 //   - this operation is invoked when allocation is failed;
  60 //     operation performs garbage collection and tries to
  61 //     allocate afterwards;
  62 //
  63 //  VM_GenCollectFull
  64 //  VM_GenCollectFullConcurrent
  65 //  VM_ParallelGCSystemGC
  66 //   - these operations preform full collection of heaps of
  67 //     different kind
  68 //
  69 
  70 class VM_GC_Operation: public VM_Operation {
  71  protected:
  72   BasicLock     _pending_list_basic_lock; // for refs pending list notification (PLL)
  73   unsigned int  _gc_count_before;         // gc count before acquiring PLL
  74   unsigned int  _full_gc_count_before;    // full gc count before acquiring PLL
  75   bool          _full;                    // whether a "full" collection
  76   bool          _prologue_succeeded;      // whether doit_prologue succeeded
  77   GCCause::Cause _gc_cause;                // the putative cause for this gc op
  78   bool          _gc_locked;               // will be set if gc was locked
  79 
  80   virtual bool skip_operation() const;
  81 
  82   // java.lang.ref.Reference support
  83   void acquire_pending_list_lock();
  84   void release_and_notify_pending_list_lock();
  85 
  86  public:
  87   VM_GC_Operation(unsigned int gc_count_before,
  88                   unsigned int full_gc_count_before = 0,
  89                   bool full = false) {
  90     _full = full;
  91     _prologue_succeeded = false;
  92     _gc_count_before    = gc_count_before;
  93 
  94     // A subclass constructor will likely overwrite the following
  95     _gc_cause           = GCCause::_no_cause_specified;
  96 
  97     _gc_locked = false;
  98 
  99     _full_gc_count_before = full_gc_count_before;
 100     // In ParallelScavengeHeap::mem_allocate() collections can be
 101     // executed within a loop and _all_soft_refs_clear can be set
 102     // true after they have been cleared by a collection and another
 103     // collection started so that _all_soft_refs_clear can be true
 104     // when this collection is started.  Don't assert that
 105     // _all_soft_refs_clear have to be false here even though
 106     // mutators have run.  Soft refs will be cleared again in this
 107     // collection.
 108   }
 109   ~VM_GC_Operation() {
 110     CollectedHeap* ch = Universe::heap();
 111     ch->collector_policy()->set_all_soft_refs_clear(false);
 112   }
 113 
 114   // Acquire the reference synchronization lock
 115   virtual bool doit_prologue();
 116   // Do notifyAll (if needed) and release held lock
 117   virtual void doit_epilogue();
 118 
 119   virtual bool allow_nested_vm_operations() const  { return true; }
 120   bool prologue_succeeded() const { return _prologue_succeeded; }
 121 
 122   void set_gc_locked() { _gc_locked = true; }
 123   bool gc_locked() const  { return _gc_locked; }
 124 
 125   static void notify_gc_begin(bool full = false);
 126   static void notify_gc_end();
 127 };
 128 
 129 
 130 class VM_GC_HeapInspection: public VM_GC_Operation {
 131  private:
 132   outputStream* _out;
 133   bool _full_gc;
 134   bool _need_prologue;
 135  public:
 136   VM_GC_HeapInspection(outputStream* out, bool request_full_gc,
 137                        bool need_prologue) :
 138     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
 139                     0 /* total full collections, dummy, ignored */,
 140                     request_full_gc) {
 141     _gc_cause = GCCause::_heap_inspection;
 142     _out = out;
 143     _full_gc = request_full_gc;
 144     _need_prologue = need_prologue;
 145   }
 146 
 147   ~VM_GC_HeapInspection() {}
 148   virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
 149   virtual bool skip_operation() const;
 150   virtual bool doit_prologue();
 151   virtual void doit();
 152 };
 153 
 154 
 155 class VM_GenCollectForAllocation: public VM_GC_Operation {
 156  private:
 157   HeapWord*   _res;
 158   size_t      _size;                       // size of object to be allocated.
 159   bool        _tlab;                       // alloc is of a tlab.
 160  public:
 161   VM_GenCollectForAllocation(size_t size,
 162                              bool tlab,
 163                              unsigned int gc_count_before)
 164     : VM_GC_Operation(gc_count_before),
 165       _size(size),
 166       _tlab(tlab) {
 167     _gc_cause = GCCause::_allocation_failure;
 168     _res = NULL;
 169   }
 170   ~VM_GenCollectForAllocation()  {}
 171   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
 172   virtual void doit();
 173   HeapWord* result() const       { return _res; }
 174 };
 175 
 176 
 177 // VM operation to invoke a collection of the heap as a
 178 // GenCollectedHeap heap.
 179 class VM_GenCollectFull: public VM_GC_Operation {
 180  private:
 181   int _max_level;
 182  public:
 183   VM_GenCollectFull(unsigned int gc_count_before,
 184                     unsigned int full_gc_count_before,
 185                     GCCause::Cause gc_cause,
 186                       int max_level)
 187     : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */),
 188       _max_level(max_level)
 189   { _gc_cause = gc_cause; }
 190   ~VM_GenCollectFull() {}
 191   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
 192   virtual void doit();
 193 };
 194 
 195 class VM_GenCollectForPermanentAllocation: public VM_GC_Operation {
 196  private:
 197   HeapWord*   _res;
 198   size_t      _size;                       // size of object to be allocated
 199  public:
 200   VM_GenCollectForPermanentAllocation(size_t size,
 201                                       unsigned int gc_count_before,
 202                                       unsigned int full_gc_count_before,
 203                                       GCCause::Cause gc_cause)
 204     : VM_GC_Operation(gc_count_before, full_gc_count_before, true),
 205       _size(size) {
 206     _res = NULL;
 207     _gc_cause = gc_cause;
 208   }
 209   ~VM_GenCollectForPermanentAllocation()  {}
 210   virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; }
 211   virtual void doit();
 212   HeapWord* result() const       { return _res; }
 213 };
 214 
 215 class SvcGCMarker : public StackObj {
 216  private:
 217   JvmtiGCMarker _jgcm;
 218  public:
 219   typedef enum { MINOR, FULL, OTHER } reason_type;
 220 
 221   SvcGCMarker(reason_type reason ) {
 222     VM_GC_Operation::notify_gc_begin(reason == FULL);
 223   }
 224 
 225   ~SvcGCMarker() {
 226     VM_GC_Operation::notify_gc_end();
 227   }
 228 };
 229 
 230 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP