1 /*
   2  * Copyright (c) 2005, 2018, 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/vmOperations.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   uint           _gc_count_before;         // gc count before acquiring PLL
  74   uint           _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  public:
  83   VM_GC_Operation(uint gc_count_before,
  84                   GCCause::Cause _cause,
  85                   uint full_gc_count_before = 0,
  86                   bool full = false) {
  87     _full = full;
  88     _prologue_succeeded = false;
  89     _gc_count_before    = gc_count_before;
  90 
  91     // A subclass constructor will likely overwrite the following
  92     _gc_cause           = _cause;
  93 
  94     _gc_locked = false;
  95 
  96     _full_gc_count_before = full_gc_count_before;
  97     // In ParallelScavengeHeap::mem_allocate() collections can be
  98     // executed within a loop and _all_soft_refs_clear can be set
  99     // true after they have been cleared by a collection and another
 100     // collection started so that _all_soft_refs_clear can be true
 101     // when this collection is started.  Don't assert that
 102     // _all_soft_refs_clear have to be false here even though
 103     // mutators have run.  Soft refs will be cleared again in this
 104     // collection.
 105   }
 106   ~VM_GC_Operation();
 107 
 108   // Acquire the reference synchronization lock
 109   virtual bool doit_prologue();
 110   // Do notifyAll (if needed) and release held lock
 111   virtual void doit_epilogue();
 112 
 113   virtual bool allow_nested_vm_operations() const  { return true; }
 114   bool prologue_succeeded() const { return _prologue_succeeded; }
 115 
 116   void set_gc_locked() { _gc_locked = true; }
 117   bool gc_locked() const  { return _gc_locked; }
 118 
 119   static void notify_gc_begin(bool full = false);
 120   static void notify_gc_end();
 121 };
 122 
 123 
 124 class VM_GC_HeapInspection: public VM_GC_Operation {
 125  private:
 126   outputStream* _out;
 127   bool _full_gc;
 128   bool _csv_format; // "comma separated values" format for spreadsheet.
 129   bool _print_help;
 130   bool _print_class_stats;
 131   const char* _columns;
 132  public:
 133   VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
 134     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
 135                     GCCause::_heap_inspection /* GC Cause */,
 136                     0 /* total full collections, dummy, ignored */,
 137                     request_full_gc) {
 138     _out = out;
 139     _full_gc = request_full_gc;
 140     _csv_format = false;
 141     _print_help = false;
 142     _print_class_stats = false;
 143     _columns = NULL;
 144   }
 145 
 146   ~VM_GC_HeapInspection() {}
 147   virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
 148   virtual bool skip_operation() const;
 149   virtual void doit();
 150   void set_csv_format(bool value) {_csv_format = value;}
 151   void set_print_help(bool value) {_print_help = value;}
 152   void set_print_class_stats(bool value) {_print_class_stats = value;}
 153   void set_columns(const char* value) {_columns = value;}
 154  protected:
 155   bool collect();
 156 };
 157 
 158 class VM_CollectForAllocation : public VM_GC_Operation {
 159  protected:
 160   size_t    _word_size; // Size of object to be allocated (in number of words)
 161   HeapWord* _result;    // Allocation result (NULL if allocation failed)
 162 
 163  public:
 164   VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
 165 
 166   HeapWord* result() const {
 167     return _result;
 168   }
 169 };
 170 
 171 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
 172  private:
 173   bool        _tlab;                       // alloc is of a tlab.
 174  public:
 175   VM_GenCollectForAllocation(size_t word_size,
 176                              bool tlab,
 177                              uint gc_count_before)
 178     : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
 179       _tlab(tlab) {
 180     assert(word_size != 0, "An allocation should always be requested with this operation.");
 181   }
 182   ~VM_GenCollectForAllocation()  {}
 183   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
 184   virtual void doit();
 185 };
 186 
 187 // VM operation to invoke a collection of the heap as a
 188 // GenCollectedHeap heap.
 189 class VM_GenCollectFull: public VM_GC_Operation {
 190  private:
 191   GenCollectedHeap::GenerationType _max_generation;
 192  public:
 193   VM_GenCollectFull(uint gc_count_before,
 194                     uint full_gc_count_before,
 195                     GCCause::Cause gc_cause,
 196                     GenCollectedHeap::GenerationType max_generation)
 197     : VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before, true /* full */),
 198       _max_generation(max_generation) { }
 199   ~VM_GenCollectFull() {}
 200   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
 201   virtual void doit();
 202 };
 203 
 204 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
 205  private:
 206   MetaWord*                _result;
 207   size_t                   _size;     // size of object to be allocated
 208   Metaspace::MetadataType  _mdtype;
 209   ClassLoaderData*         _loader_data;
 210 
 211  public:
 212   VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
 213                                   size_t size,
 214                                   Metaspace::MetadataType mdtype,
 215                                   uint gc_count_before,
 216                                   uint full_gc_count_before,
 217                                   GCCause::Cause gc_cause);
 218 
 219   virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
 220   virtual void doit();
 221   MetaWord* result() const       { return _result; }
 222 
 223   bool initiate_concurrent_GC();
 224 };
 225 
 226 class SvcGCMarker : public StackObj {
 227  private:
 228   JvmtiGCMarker _jgcm;
 229  public:
 230   typedef enum { MINOR, FULL, CONCURRENT } reason_type;
 231 
 232   SvcGCMarker(reason_type reason ) {
 233     VM_GC_Operation::notify_gc_begin(reason == FULL);
 234   }
 235 
 236   ~SvcGCMarker() {
 237     VM_GC_Operation::notify_gc_end();
 238   }
 239 };
 240 
 241 #endif // SHARE_VM_GC_SHARED_VMGCOPERATIONS_HPP