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products/sources/formale Sprachen/Java/Openjdk/src/hotspot/share/gc/parallel/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 4 kB

Quelle psVirtualspace.cpp Sprache: C

/*
* Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#include "precompiled.hpp"
#include "gc/parallel/psVirtualspace.hpp"
#include "memory/virtualspace.hpp"
#include "runtime/os.hpp"

// PSVirtualSpace

PSVirtualSpace::PSVirtualSpace(ReservedSpace rs, size_t alignment) :
  _alignment(alignment)
{
  set_reserved(rs);
  set_committed(reserved_low_addr(), reserved_low_addr());
  DEBUG_ONLY(verify());
}

// Deprecated.
PSVirtualSpace::PSVirtualSpace():
  _alignment(os::vm_page_size()),
  _reserved_low_addr(NULL),
  _reserved_high_addr(NULL),
  _committed_low_addr(NULL),
  _committed_high_addr(NULL),
  _special(false) {
}

// Deprecated.
void PSVirtualSpace::initialize(ReservedSpace rs) {
  set_reserved(rs);
  set_committed(reserved_low_addr(), reserved_low_addr());
  DEBUG_ONLY(verify());
}

PSVirtualSpace::~PSVirtualSpace() {
  release();
}

void PSVirtualSpace::release() {
  DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));
  // This may not release memory it didn't reserve.
  // Use rs.release() to release the underlying memory instead.
  _reserved_low_addr = _reserved_high_addr = NULL;
  _committed_low_addr = _committed_high_addr = NULL;
  _special = false;
}

bool PSVirtualSpace::expand_by(size_t bytes) {
  assert(is_aligned(bytes), "arg not aligned");
  DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));

  if (uncommitted_size() < bytes) {
    return false;
  }

  char* const base_addr = committed_high_addr();
  bool result = special() ||
         os::commit_memory(base_addr, bytes, alignment(), !ExecMem);
  if (result) {
    _committed_high_addr += bytes;
  }

  return result;
}

bool PSVirtualSpace::shrink_by(size_t bytes) {
  assert(is_aligned(bytes), "arg not aligned");
  DEBUG_ONLY(PSVirtualSpaceVerifier this_verifier(this));

  if (committed_size() < bytes) {
    return false;
  }

  char* const base_addr = committed_high_addr() - bytes;
  bool result = special() || os::uncommit_memory(base_addr, bytes);
  if (result) {
    _committed_high_addr -= bytes;
  }

  return result;
}

#ifndef PRODUCT
bool PSVirtualSpace::is_aligned(size_t value, size_t align) {
  const size_t tmp_value = value + align - 1;
  const size_t mask = ~(align - 1);
  return (tmp_value & mask) == value;
}

bool PSVirtualSpace::is_aligned(size_t value) const {
  return is_aligned(value, alignment());
}

bool PSVirtualSpace::is_aligned(char* value) const {
  return is_aligned((size_t)value);
}

void PSVirtualSpace::verify() const {
  assert(is_aligned(alignment(), os::vm_page_size()), "bad alignment");
  assert(is_aligned(reserved_low_addr()), "bad reserved_low_addr");
  assert(is_aligned(reserved_high_addr()), "bad reserved_high_addr");
  assert(is_aligned(committed_low_addr()), "bad committed_low_addr");
  assert(is_aligned(committed_high_addr()), "bad committed_high_addr");

  // Reserved region must be non-empty or both addrs must be 0.
  assert(reserved_low_addr() < reserved_high_addr() ||
         reserved_low_addr() == NULL && reserved_high_addr() == NULL,
         "bad reserved addrs");
  assert(committed_low_addr() <= committed_high_addr(), "bad committed addrs");

  // committed addr grows up
  assert(reserved_low_addr() == committed_low_addr(), "bad low addrs");
  assert(reserved_high_addr() >= committed_high_addr(), "bad high addrs");
}

#endif // #ifndef PRODUCT

void PSVirtualSpace::print_space_boundaries_on(outputStream* st) const {
  st->print_cr(" [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ")",
               p2i(low_boundary()), p2i(high()), p2i(high_boundary()));
}

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