1 /*
   2  * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2020 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 
  28 #include "memory/metaspace/commitLimiter.hpp"
  29 #include "memory/metaspace.hpp"
  30 #include "utilities/debug.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 
  33 namespace metaspace {
  34 
  35 // Returns the size, in words, by which we may expand the metaspace committed area without:
  36 // - _cap == 0: hitting GC threshold or the MaxMetaspaceSize
  37 // - _cap > 0: hitting cap (this is just for testing purposes)
  38 size_t CommitLimiter::possible_expansion_words() const {
  39 
  40   if (_cap > 0) { // Testing.
  41     assert(_cnt.get() <= _cap, "Beyond limit?");
  42     return _cap - _cnt.get();
  43   }
  44 
  45   assert(_cnt.get() * BytesPerWord <= MaxMetaspaceSize, "Beyond limit?");
  46   const size_t words_left_below_max = MaxMetaspaceSize / BytesPerWord - _cnt.get();
  47 
  48   const size_t words_left_below_gc_threshold = MetaspaceGC::allowed_expansion();
  49 
  50   return MIN2(words_left_below_max, words_left_below_gc_threshold);
  51 
  52 }
  53 
  54 static CommitLimiter g_global_limiter(0);
  55 
  56 // Returns the global metaspace commit counter
  57 CommitLimiter* CommitLimiter::globalLimiter() {
  58   return &g_global_limiter;
  59 }
  60 
  61 } // namespace metaspace
  62