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 #ifndef SHARE_MEMORY_METASPACE_MSSETTINGS_HPP
  27 #define SHARE_MEMORY_METASPACE_MSSETTINGS_HPP
  28 
  29 #include "memory/allocation.hpp"
  30 #include "memory/metaspace/msChunklevel.hpp"
  31 #include "utilities/globalDefinitions.hpp"
  32 
  33 namespace metaspace {
  34 
  35 class Settings : public AllStatic {
  36 
  37   // Granularity, in bytes, metaspace is committed with.
  38   static size_t _commit_granule_bytes;
  39 
  40   // Granularity, in words, metaspace is committed with.
  41   static size_t _commit_granule_words;
  42 
  43   // The default size of a non-class VirtualSpaceNode (unless created differently).
  44   // Must be a multiple of the root chunk size.
  45   static const size_t VirtualSpaceNodeDefaultWordSize = chunklevel::MAX_CHUNK_WORD_SIZE * 2; // lets go with 8mb virt size. Seems a good compromise betw. virt and mapping fragmentation.
  46 
  47   // Alignment of the base address of a virtual space node
  48   static const size_t VirtualSpaceNodeReserveAlignmentWordSize = chunklevel::MAX_CHUNK_WORD_SIZE;
  49 
  50   // When allocating from a chunk, if the remaining area in the chunk is too small to hold
  51   // the requested size, we attempt to double the chunk size in place...
  52   static const bool EnlargeChunksInPlace = true;
  53 
  54   // Whether or not chunks handed out to an arena start out fully committed;
  55   // if true, this deactivates committing-on-demand (irregardless of whether
  56   // we uncommit free chunks).
  57   static bool _new_chunks_are_fully_committed;
  58 
  59   // If true, chunks equal or larger than a commit granule are uncommitted
  60   // after being returned to the freelist.
  61   static bool _uncommit_free_chunks;
  62 
  63   // If true, metablock allocations are guarded and periodically checked.
  64   DEBUG_ONLY(static bool _use_allocation_guard;)
  65 
  66   // If true, we handle deallocated blocks (default).
  67   DEBUG_ONLY(static bool _handle_deallocations;)
  68 
  69 public:
  70 
  71   static size_t commit_granule_bytes()                        { return _commit_granule_bytes; }
  72   static size_t commit_granule_words()                        { return _commit_granule_words; }
  73   static bool new_chunks_are_fully_committed()                { return _new_chunks_are_fully_committed; }
  74   static size_t virtual_space_node_default_word_size()        { return VirtualSpaceNodeDefaultWordSize; }
  75   static size_t virtual_space_node_reserve_alignment_words()  { return VirtualSpaceNodeReserveAlignmentWordSize; }
  76   static bool enlarge_chunks_in_place()                       { return EnlargeChunksInPlace; }
  77   static bool uncommit_free_chunks()                          { return _uncommit_free_chunks; }
  78 
  79   static bool use_allocation_guard()                          { return DEBUG_ONLY(_use_allocation_guard) NOT_DEBUG(false); }
  80   static bool handle_deallocations()                          { return DEBUG_ONLY(_handle_deallocations) NOT_DEBUG(true); }
  81 
  82   static void ergo_initialize();
  83 
  84   static void print_on(outputStream* st);
  85 
  86 };
  87 
  88 } // namespace metaspace
  89 
  90 #endif // SHARE_MEMORY_METASPACE_MSSETTINGS_HPP