1 /*
   2  * Copyright (c) 2017, 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
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  24 
  25 #ifndef SHARE_VM_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP
  26 #define SHARE_VM_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP
  27 
  28 #include "jfr/utilities/jfrAllocation.hpp"
  29 
  30 class JfrVirtualMemoryManager;
  31 
  32 class JfrVirtualMemory : public JfrCHeapObj {
  33  private:
  34   JfrVirtualMemoryManager* _vmm;
  35   const u1* _reserved_low; // lowest address of reservation
  36   const u1* _reserved_high; // highest address of reservation
  37   u1* _top; // current allocation address
  38   const u1* _commit_point; // synch points for committing new memory
  39   size_t _physical_commit_size_request_words; // aligned to os::vm_allocation_granularity()
  40   size_t _aligned_datum_size_bytes; // datum alignment
  41 
  42   bool commit_memory_block();
  43   void* commit(size_t block_size_request_words);
  44   void* index_ptr(size_t index); // index to address map
  45 
  46  public:
  47   JfrVirtualMemory();
  48   ~JfrVirtualMemory();
  49 
  50   // initialization will do the reservation and return it
  51   void* initialize(size_t reservation_size_request_bytes, size_t block_size_request_bytes, size_t datum_size_bytes = 1);
  52 
  53   void* new_datum(); // datum oriented allocation
  54   void* get(size_t index); // direct access retrieval
  55   size_t aligned_datum_size_bytes() const;
  56 
  57   bool is_full() const; // limit of reservation committed and in use
  58   bool is_empty() const;
  59 
  60   size_t count() const; // how many
  61   size_t live_set() const; // how much resident memory (actually in use)
  62   size_t reserved_size() const; // size of reservation
  63   bool compact(size_t index);
  64 };
  65 
  66 #endif // SHARE_VM_JFR_RECORDER_STORAGE_JFRVIRTUALMEMORY_HPP