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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  23  */
  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/gcId.hpp"
  30 #include "gc/shared/genCollectedHeap.hpp"
  31 #include "memory/heapInspection.hpp"
  32 #include "prims/jvmtiExport.hpp"
  33 #include "runtime/handles.hpp"
  34 #include "runtime/jniHandles.hpp"
  35 #include "runtime/synchronizer.hpp"
  36 #include "runtime/vm_operations.hpp"
  37 
  38 // The following class hierarchy represents
  39 // a set of operations (VM_Operation) related to GC.
  40 //
  41 //  VM_Operation
  42 //      VM_GC_Operation
  43 //          VM_GC_HeapInspection
  44 //          VM_GenCollectFull
  45 //          VM_GenCollectFullConcurrent
  46 //          VM_ParallelGCSystemGC
  47 //          VM_CollectForAllocation
  48 //              VM_GenCollectForAllocation
  49 //              VM_ParallelGCFailedAllocation
  50 //  VM_GC_Operation
  51 //   - implements methods common to all classes in the hierarchy:
  52 //     prevents multiple gc requests and manages lock on heap;
  53 //
  54 //  VM_GC_HeapInspection
  55 //   - prints class histogram on SIGBREAK if PrintClassHistogram
  56 //     is specified; and also the attach "inspectheap" operation
  57 //
  58 //  VM_CollectForAllocation
  59 //  VM_GenCollectForAllocation
  60 //  VM_ParallelGCFailedAllocation
  61 //   - this operation is invoked when allocation is failed;
  62 //     operation performs garbage collection and tries to
  63 //     allocate afterwards;
  64 //
  65 //  VM_GenCollectFull
  66 //  VM_GenCollectFullConcurrent
  67 //  VM_ParallelGCSystemGC
  68 //   - these operations preform full collection of heaps of
  69 //     different kind
  70 //
  71 
  72 class VM_GC_Operation: public VM_Operation {
  73  protected:
  74   BasicLock      _pending_list_basic_lock; // for refs pending list notification (PLL)
  75   uint           _gc_count_before;         // gc count before acquiring PLL
  76   uint           _full_gc_count_before;    // full gc count before acquiring PLL
  77   bool           _full;                    // whether a "full" collection
  78   bool           _prologue_succeeded;      // whether doit_prologue succeeded
  79   GCCause::Cause _gc_cause;                // the putative cause for this gc op
  80   bool           _gc_locked;               // will be set if gc was locked
  81 
  82   virtual bool skip_operation() const;
  83 
  84   // java.lang.ref.Reference support
  85   void acquire_pending_list_lock();
  86   void release_and_notify_pending_list_lock();
  87 
  88  public:
  89   VM_GC_Operation(uint gc_count_before,
  90                   GCCause::Cause _cause,
  91                   uint full_gc_count_before = 0,
  92                   bool full = false) {
  93     _full = full;
  94     _prologue_succeeded = false;
  95     _gc_count_before    = gc_count_before;
  96 
  97     // A subclass constructor will likely overwrite the following
  98     _gc_cause           = _cause;
  99 
 100     _gc_locked = false;
 101 
 102     _full_gc_count_before = full_gc_count_before;
 103     // In ParallelScavengeHeap::mem_allocate() collections can be
 104     // executed within a loop and _all_soft_refs_clear can be set
 105     // true after they have been cleared by a collection and another
 106     // collection started so that _all_soft_refs_clear can be true
 107     // when this collection is started.  Don't assert that
 108     // _all_soft_refs_clear have to be false here even though
 109     // mutators have run.  Soft refs will be cleared again in this
 110     // collection.
 111   }
 112   ~VM_GC_Operation();
 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 _csv_format; // "comma separated values" format for spreadsheet.
 135   bool _print_help;
 136   bool _print_class_stats;
 137   const char* _columns;
 138  public:
 139   VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
 140     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
 141                     GCCause::_heap_inspection /* GC Cause */,
 142                     0 /* total full collections, dummy, ignored */,
 143                     request_full_gc) {
 144     _out = out;
 145     _full_gc = request_full_gc;
 146     _csv_format = false;
 147     _print_help = false;
 148     _print_class_stats = false;
 149     _columns = NULL;
 150   }
 151 
 152   ~VM_GC_HeapInspection() {}
 153   virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
 154   virtual bool skip_operation() const;
 155   virtual void doit();
 156   void set_csv_format(bool value) {_csv_format = value;}
 157   void set_print_help(bool value) {_print_help = value;}
 158   void set_print_class_stats(bool value) {_print_class_stats = value;}
 159   void set_columns(const char* value) {_columns = value;}
 160  protected:
 161   bool collect();
 162 };
 163 
 164 class VM_CollectForAllocation : public VM_GC_Operation {
 165  protected:
 166   size_t    _word_size; // Size of object to be allocated (in number of words)
 167   HeapWord* _result;    // Allocation result (NULL if allocation failed)
 168 
 169  public:
 170   VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
 171 
 172   HeapWord* result() const {
 173     return _result;
 174   }
 175 };
 176 
 177 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
 178  private:
 179   bool        _tlab;                       // alloc is of a tlab.
 180  public:
 181   VM_GenCollectForAllocation(size_t word_size,
 182                              bool tlab,
 183                              uint gc_count_before)
 184     : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
 185       _tlab(tlab) {
 186     assert(word_size != 0, "An allocation should always be requested with this operation.");
 187   }
 188   ~VM_GenCollectForAllocation()  {}
 189   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
 190   virtual void doit();
 191 };
 192 
 193 // VM operation to invoke a collection of the heap as a
 194 // GenCollectedHeap heap.
 195 class VM_GenCollectFull: public VM_GC_Operation {
 196  private:
 197   GenCollectedHeap::GenerationType _max_generation;
 198  public:
 199   VM_GenCollectFull(uint gc_count_before,
 200                     uint full_gc_count_before,
 201                     GCCause::Cause gc_cause,
 202                     GenCollectedHeap::GenerationType max_generation)
 203     : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
 204       _max_generation(max_generation) { }
 205   ~VM_GenCollectFull() {}
 206   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
 207   virtual void doit();
 208 };
 209 
 210 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
 211  private:
 212   MetaWord*                _result;
 213   size_t                   _size;     // size of object to be allocated
 214   Metaspace::MetadataType  _mdtype;
 215   ClassLoaderData*         _loader_data;
 216  public:
 217   VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
 218                                   size_t size, Metaspace::MetadataType mdtype,
 219                                   uint gc_count_before,
 220                                   uint full_gc_count_before,
 221                                   GCCause::Cause gc_cause);
 222   virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
 223   virtual void doit();
 224   MetaWord* result() const       { return _result; }
 225 
 226   bool initiate_concurrent_GC();
 227 };
 228 
 229 class SvcGCMarker : public StackObj {
 230  private:
 231   JvmtiGCMarker _jgcm;
 232  public:
 233   typedef enum { MINOR, FULL, OTHER } reason_type;
 234 
 235   SvcGCMarker(reason_type reason ) {
 236     VM_GC_Operation::notify_gc_begin(reason == FULL);
 237   }
 238 
 239   ~SvcGCMarker() {
 240     VM_GC_Operation::notify_gc_end();
 241   }
 242 };
 243 
 244 #endif // SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP