1 /*
   2  * Copyright (c) 2018, 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.
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  23  */
  24 
  25 #ifndef SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP
  26 #define SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP
  27 
  28 #include "memory/allocation.hpp"
  29 #include "memory/metaspace/counter.hpp"
  30 
  31 namespace metaspace {
  32 
  33 class CommitLimiter : public CHeapObj<mtInternal> {
  34 
  35   // Counts total words committed for metaspace
  36   SizeCounter _cnt;
  37 
  38   // Purely for testing purposes.
  39   const size_t _cap;
  40 
  41 public:
  42 
  43   CommitLimiter(size_t cap = 0) : _cnt(), _cap(cap) {}
  44 
  45   // Returns the size, in words, by which we may expand the metaspace committed area without:
  46   // - _cap == 0: hitting GC threshold or the MaxMetaspaceSize
  47   // - _cap > 0: hitting cap (this is just for testing purposes)
  48   size_t possible_expansion_words() const;
  49 
  50   void increase_committed(size_t word_size)   { _cnt.increment_by(word_size); }
  51   void decrease_committed(size_t word_size)   { _cnt.decrement_by(word_size); }
  52   size_t committed_words() const              { return _cnt.get(); }
  53 
  54   // Returns the global metaspace commit counter
  55   static CommitLimiter* globalLimiter();
  56 
  57 };
  58 
  59 } // namespace metaspace
  60 
  61 #endif // SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP