1 /*
   2  * Copyright (c) 2002, 2019, 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_GC_CMS_GSPACECOUNTERS_HPP
  26 #define SHARE_GC_CMS_GSPACECOUNTERS_HPP
  27 
  28 #include "gc/shared/generation.hpp"
  29 #include "gc/shared/generationCounters.hpp"
  30 #include "runtime/perfData.hpp"
  31 #include "utilities/macros.hpp"
  32 
  33 // A GSpaceCounter is a holder class for performance counters
  34 // that track a space;
  35 
  36 class GSpaceCounters: public CHeapObj<mtGC> {
  37   friend class VMStructs;
  38 
  39  private:
  40   PerfVariable*      _capacity;
  41   PerfVariable*      _used;
  42 
  43   // Constant PerfData types don't need to retain a reference.
  44   // However, it's a good idea to document them here.
  45   // PerfConstant*     _size;
  46 
  47   Generation*       _gen;
  48   char*             _name_space;
  49 
  50  public:
  51 
  52   GSpaceCounters(const char* name, int ordinal, size_t max_size, Generation* g,
  53                  GenerationCounters* gc, bool sampled=true);
  54 
  55   ~GSpaceCounters();
  56 
  57   inline void update_capacity() {
  58     _capacity->set_value(_gen->capacity());
  59   }
  60 
  61   inline void update_used() {
  62     _used->set_value(_gen->used());
  63   }
  64 
  65   // special version of update_used() to allow the used value to be
  66   // passed as a parameter. This method can can be used in cases were
  67   // the  utilization is already known and/or when the _gen->used()
  68   // method is known to be expensive and we want to avoid unnecessary
  69   // calls to it.
  70   //
  71   inline void update_used(size_t used) {
  72     _used->set_value(used);
  73   }
  74 
  75   inline void inc_used(size_t size) {
  76     _used->inc(size);
  77   }
  78 
  79   debug_only(
  80     // for security reasons, we do not allow arbitrary reads from
  81     // the counters as they may live in shared memory.
  82     jlong used() {
  83       return _used->get_value();
  84     }
  85     jlong capacity() {
  86       return _used->get_value();
  87     }
  88   )
  89 
  90   inline void update_all() {
  91     update_used();
  92     update_capacity();
  93   }
  94 
  95   const char* name_space() const        { return _name_space; }
  96 };
  97 
  98 class GenerationUsedHelper : public PerfLongSampleHelper {
  99   private:
 100     Generation* _gen;
 101 
 102   public:
 103     GenerationUsedHelper(Generation* g) : _gen(g) { }
 104 
 105     inline jlong take_sample() {
 106       return _gen->used();
 107     }
 108 };
 109 
 110 #endif // SHARE_GC_CMS_GSPACECOUNTERS_HPP