1 /*

     2  * Copyright (c) 2005, 2016, 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_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   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, OTHER } 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