1 /*
   2  * Copyright (c) 2015, 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.
  22  */
  23 
  24 #ifndef OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP
  25 #define OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP
  26 
  27 #include "memory/allocation.hpp"
  28 
  29 class ZErrno;
  30 
  31 class ZBackingFile {
  32 private:
  33   int      _fd;
  34   size_t   _size;
  35   uint64_t _filesystem;
  36   size_t   _block_size;
  37   size_t   _available;
  38   bool     _initialized;
  39 
  40   void warn_available_space(size_t max) const;
  41   void warn_max_map_count(size_t max) const;
  42 
  43   int create_mem_fd(const char* name) const;
  44   int create_file_fd(const char* name) const;
  45   int create_fd(const char* name) const;
  46 
  47   bool is_tmpfs() const;
  48   bool is_hugetlbfs() const;
  49   bool tmpfs_supports_transparent_huge_pages() const;
  50 
  51   ZErrno fallocate_compat_ftruncate(size_t size) const;
  52   ZErrno fallocate_compat_mmap(size_t offset, size_t length, bool reserve_only) const;
  53   ZErrno fallocate_compat_pwrite(size_t offset, size_t length) const;
  54   ZErrno fallocate_fill_hole_compat(size_t offset, size_t length);
  55   ZErrno fallocate_fill_hole_syscall(size_t offset, size_t length);
  56   ZErrno fallocate_fill_hole(size_t offset, size_t length);
  57   ZErrno fallocate_punch_hole(size_t offset, size_t length);
  58   ZErrno split_and_fallocate(bool punch_hole, size_t offset, size_t length);
  59   ZErrno fallocate(bool punch_hole, size_t offset, size_t length);
  60 
  61   bool commit_inner(size_t offset, size_t length);
  62 
  63 public:
  64   ZBackingFile();
  65 
  66   bool is_initialized() const;
  67 
  68   void warn_commit_limits(size_t max) const;
  69 
  70   size_t size() const;
  71 
  72   size_t commit(size_t offset, size_t length);
  73   size_t uncommit(size_t offset, size_t length);
  74 
  75   void map(uintptr_t addr, size_t size, uintptr_t offset) const;
  76   void unmap(uintptr_t addr, size_t size) const;
  77 };
  78 
  79 #endif // OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP