1 /*
   2  * Copyright (c) 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
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 
  27 #include "memory/metaspace/commitLimiter.hpp"
  28 #include "memory/metaspace.hpp"
  29 #include "utilities/debug.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 
  32 namespace metaspace {
  33 
  34 // Returns the size, in words, by which we may expand the metaspace committed area without:
  35 // - _cap == 0: hitting GC threshold or the MaxMetaspaceSize
  36 // - _cap > 0: hitting cap (this is just for testing purposes)
  37 size_t CommitLimiter::possible_expansion_words() const {
  38 
  39   if (_cap > 0) { // Testing.
  40     assert(_cnt.get() <= _cap, "Beyond limit?");
  41     return _cap - _cnt.get();
  42   }
  43 
  44   assert(_cnt.get() * BytesPerWord <= MaxMetaspaceSize, "Beyond limit?");
  45   const size_t words_left_below_max = MaxMetaspaceSize / BytesPerWord - _cnt.get();
  46 
  47   const size_t words_left_below_gc_threshold = MetaspaceGC::allowed_expansion();
  48 
  49   return MIN2(words_left_below_max, words_left_below_gc_threshold);
  50 
  51 }
  52 
  53 static CommitLimiter g_global_limiter(0);
  54 
  55 // Returns the global metaspace commit counter
  56 CommitLimiter* CommitLimiter::globalLimiter() {
  57   return &g_global_limiter;
  58 }
  59 
  60 } // namespace metaspace
  61