1 /*
   2  * Copyright (c) 2005, 2015, 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
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  24 
  25 #ifndef SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP
  26 #define SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP
  27 
  28 #include "gc/shared/collectedHeap.hpp"
  29 #include "gc/shared/genCollectedHeap.hpp"
  30 #include "memory/heapInspection.hpp"
  31 #include "prims/jvmtiExport.hpp"
  32 #include "runtime/handles.hpp"
  33 #include "runtime/jniHandles.hpp"
  34 #include "runtime/synchronizer.hpp"
  35 #include "runtime/vm_operations.hpp"
  36 
  37 // The following class hierarchy represents
  38 // a set of operations (VM_Operation) related to GC.
  39 //
  40 //  VM_Operation
  41 //      VM_GC_Operation
  42 //          VM_GC_HeapInspection
  43 //          VM_GenCollectFull
  44 //          VM_GenCollectFullConcurrent
  45 //          VM_ParallelGCSystemGC
  46 //          VM_CollectForAllocation
  47 //              VM_GenCollectForAllocation
  48 //              VM_ParallelGCFailedAllocation
  49 //  VM_GC_Operation
  50 //   - implements methods common to all classes in the hierarchy:
  51 //     prevents multiple gc requests and manages lock on heap;
  52 //
  53 //  VM_GC_HeapInspection
  54 //   - prints class histogram on SIGBREAK if PrintClassHistogram
  55 //     is specified; and also the attach "inspectheap" operation
  56 //
  57 //  VM_CollectForAllocation
  58 //  VM_GenCollectForAllocation
  59 //  VM_ParallelGCFailedAllocation
  60 //   - this operation is invoked when allocation is failed;
  61 //     operation performs garbage collection and tries to
  62 //     allocate afterwards;
  63 //
  64 //  VM_GenCollectFull
  65 //  VM_GenCollectFullConcurrent
  66 //  VM_ParallelGCSystemGC
  67 //   - these operations preform full collection of heaps of
  68 //     different kind
  69 //
  70 
  71 class VM_GC_Operation: public VM_Operation {
  72  protected:
  73   BasicLock      _pending_list_basic_lock; // for refs pending list notification (PLL)
  74   uint           _gc_count_before;         // gc count before acquiring PLL
  75   uint           _full_gc_count_before;    // full gc count before acquiring PLL
  76   bool           _full;                    // whether a "full" collection
  77   bool           _prologue_succeeded;      // whether doit_prologue succeeded
  78   GCCause::Cause _gc_cause;                // the putative cause for this gc op
  79   bool           _gc_locked;               // will be set if gc was locked
  80 
  81   virtual bool skip_operation() const;
  82 
  83   // java.lang.ref.Reference support
  84   void acquire_pending_list_lock();
  85   void release_and_notify_pending_list_lock();
  86 
  87  public:
  88   VM_GC_Operation(uint gc_count_before,
  89                   GCCause::Cause _cause,
  90                   uint full_gc_count_before = 0,
  91                   bool full = false) {
  92     _full = full;
  93     _prologue_succeeded = false;
  94     _gc_count_before    = gc_count_before;
  95 
  96     // A subclass constructor will likely overwrite the following
  97     _gc_cause           = _cause;
  98 
  99     _gc_locked = false;
 100 
 101     _full_gc_count_before = full_gc_count_before;
 102     // In ParallelScavengeHeap::mem_allocate() collections can be
 103     // executed within a loop and _all_soft_refs_clear can be set
 104     // true after they have been cleared by a collection and another
 105     // collection started so that _all_soft_refs_clear can be true
 106     // when this collection is started.  Don't assert that
 107     // _all_soft_refs_clear have to be false here even though
 108     // mutators have run.  Soft refs will be cleared again in this
 109     // collection.
 110   }
 111   ~VM_GC_Operation();
 112 
 113   // Acquire the reference synchronization lock
 114   virtual bool doit_prologue();
 115   // Do notifyAll (if needed) and release held lock
 116   virtual void doit_epilogue();
 117 
 118   virtual bool allow_nested_vm_operations() const  { return true; }
 119   bool prologue_succeeded() const { return _prologue_succeeded; }
 120 
 121   void set_gc_locked() { _gc_locked = true; }
 122   bool gc_locked() const  { return _gc_locked; }
 123 
 124   static void notify_gc_begin(bool full = false);
 125   static void notify_gc_end();
 126 };
 127 
 128 
 129 class VM_GC_HeapInspection: public VM_GC_Operation {
 130  private:
 131   outputStream* _out;
 132   bool _full_gc;
 133   bool _csv_format; // "comma separated values" format for spreadsheet.
 134   bool _print_help;
 135   bool _print_class_stats;
 136   const char* _columns;
 137  public:
 138   VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
 139     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
 140                     GCCause::_heap_inspection /* GC Cause */,
 141                     0 /* total full collections, dummy, ignored */,
 142                     request_full_gc) {
 143     _out = out;
 144     _full_gc = request_full_gc;
 145     _csv_format = false;
 146     _print_help = false;
 147     _print_class_stats = false;
 148     _columns = NULL;
 149   }
 150 
 151   ~VM_GC_HeapInspection() {}
 152   virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
 153   virtual bool skip_operation() const;
 154   virtual void doit();
 155   void set_csv_format(bool value) {_csv_format = value;}
 156   void set_print_help(bool value) {_print_help = value;}
 157   void set_print_class_stats(bool value) {_print_class_stats = value;}
 158   void set_columns(const char* value) {_columns = value;}
 159  protected:
 160   bool collect();
 161 };
 162 
 163 class VM_CollectForAllocation : public VM_GC_Operation {
 164  protected:
 165   size_t    _word_size; // Size of object to be allocated (in number of words)
 166   HeapWord* _result;    // Allocation result (NULL if allocation failed)
 167 
 168  public:
 169   VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
 170 
 171   HeapWord* result() const {
 172     return _result;
 173   }
 174 };
 175 
 176 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
 177  private:
 178   bool        _tlab;                       // alloc is of a tlab.
 179  public:
 180   VM_GenCollectForAllocation(size_t word_size,
 181                              bool tlab,
 182                              uint gc_count_before)
 183     : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
 184       _tlab(tlab) {
 185     assert(word_size != 0, "An allocation should always be requested with this operation.");
 186   }
 187   ~VM_GenCollectForAllocation()  {}
 188   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
 189   virtual void doit();
 190 };
 191 
 192 // VM operation to invoke a collection of the heap as a
 193 // GenCollectedHeap heap.
 194 class VM_GenCollectFull: public VM_GC_Operation {
 195  private:
 196   GenCollectedHeap::GenerationType _max_generation;
 197  public:
 198   VM_GenCollectFull(uint gc_count_before,
 199                     uint full_gc_count_before,
 200                     GCCause::Cause gc_cause,
 201                     GenCollectedHeap::GenerationType max_generation)
 202     : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
 203       _max_generation(max_generation) { }
 204   ~VM_GenCollectFull() {}
 205   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
 206   virtual void doit();
 207 };
 208 
 209 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
 210  private:
 211   MetaWord*                _result;
 212   size_t                   _size;     // size of object to be allocated
 213   Metaspace::MetadataType  _mdtype;
 214   ClassLoaderData*         _loader_data;
 215 
 216  public:
 217   VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
 218                                   size_t size,
 219                                   Metaspace::MetadataType mdtype,
 220                                   uint gc_count_before,
 221                                   uint full_gc_count_before,
 222                                   GCCause::Cause gc_cause);
 223 
 224   virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
 225   virtual void doit();
 226   MetaWord* result() const       { return _result; }
 227 
 228   bool initiate_concurrent_GC();
 229 };
 230 
 231 class SvcGCMarker : public StackObj {
 232  private:
 233   JvmtiGCMarker _jgcm;
 234  public:
 235   typedef enum { MINOR, FULL, OTHER } reason_type;
 236 
 237   SvcGCMarker(reason_type reason ) {
 238     VM_GC_Operation::notify_gc_begin(reason == FULL);
 239   }
 240 
 241   ~SvcGCMarker() {
 242     VM_GC_Operation::notify_gc_end();
 243   }
 244 };
 245 
 246 #endif // SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP