/*
 * Copyright (c) 2014, 2015, 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_implementation/g1/g1PageBasedVirtualSpace.hpp"
#include "oops/markOop.hpp"
#include "oops/oop.inline.hpp"
#include "services/memTracker.hpp"
#ifdef TARGET_OS_FAMILY_linux
# include "os_linux.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_solaris
# include "os_solaris.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_windows
# include "os_windows.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_aix
# include "os_aix.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_bsd
# include "os_bsd.inline.hpp"
#endif
#include "utilities/bitMap.inline.hpp"

G1PageBasedVirtualSpace::G1PageBasedVirtualSpace() : _low_boundary(NULL),
  _high_boundary(NULL), _committed(), _commit_size(0), _special(false),
  _dirty(), _executable(false) {
}

bool G1PageBasedVirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t actual_size, size_t commit_size) {
  if (!rs.is_reserved()) {
    return false;  // Allocation failed.
  }
  assert(_low_boundary == NULL, "VirtualSpace already initialized");
  assert(commit_size > 0, "Granularity must be non-zero.");

  guarantee(is_ptr_aligned(rs.base(), commit_size),
            err_msg("Reserved space base " PTR_FORMAT" is not aligned to requested page size " SIZE_FORMAT, p2i(rs.base()), commit_size));
  guarantee(is_size_aligned(actual_size, os::vm_page_size()),
            err_msg("Given actual reserved space size needs to be OS page size aligned (%d bytes) but is " SIZE_FORMAT, os::vm_page_size(), actual_size));
  guarantee(actual_size <= rs.size(),
            err_msg("Actual size of reserved space " SIZE_FORMAT" bytes is smaller than reservation at " SIZE_FORMAT" bytes", actual_size, rs.size()));

  _low_boundary  = rs.base();
  _high_boundary = _low_boundary + actual_size;

  _special = rs.special();
  _executable = rs.executable();

  _commit_size = commit_size;

  assert(_committed.size() == 0, "virtual space initialized more than once");
  BitMap::idx_t size_in_pages = align_size_up(rs.size(), commit_size) / commit_size;
  _committed.resize(size_in_pages, /* in_resource_area */ false);
  if (_special) {
    _dirty.resize(size_in_pages, /* in_resource_area */ false);
  }

  return true;
}

G1PageBasedVirtualSpace::~G1PageBasedVirtualSpace() {
  release();
}

void G1PageBasedVirtualSpace::release() {
  // This does not release memory it never reserved.
  // Caller must release via rs.release();
  _low_boundary           = NULL;
  _high_boundary          = NULL;
  _special                = false;
  _executable             = false;
  _commit_size            = 0;
  _committed.resize(0, false);
  _dirty.resize(0, false);
}

size_t G1PageBasedVirtualSpace::committed_size() const {
  size_t result = _committed.count_one_bits() * _commit_size;
  // The last page might not be in full.
  if (_committed.at(_committed.size()-1)) {
    result -= pointer_delta((char*)align_ptr_up(_high_boundary, _commit_size), _high_boundary, sizeof(char));
  }
  return result;
}

size_t G1PageBasedVirtualSpace::reserved_size() const {
  return pointer_delta(_high_boundary, _low_boundary, sizeof(char));
}

size_t G1PageBasedVirtualSpace::uncommitted_size()  const {
  return reserved_size() - committed_size();
}

uintptr_t G1PageBasedVirtualSpace::addr_to_page_index(char* addr) const {
  return (addr - _low_boundary) / _commit_size;
}

bool G1PageBasedVirtualSpace::is_area_committed(uintptr_t start, size_t size_in_pages) const {
  uintptr_t end = start + size_in_pages;
  return _committed.get_next_zero_offset(start, end) >= end;
}

bool G1PageBasedVirtualSpace::is_area_uncommitted(uintptr_t start, size_t size_in_pages) const {
  uintptr_t end = start + size_in_pages;
  return _committed.get_next_one_offset(start, end) >= end;
}

char* G1PageBasedVirtualSpace::page_start(uintptr_t index) {
  return _low_boundary + index * _commit_size;
}

char* G1PageBasedVirtualSpace::page_end(uintptr_t index) {
  guarantee(index < _committed.size(), "invariant");
  if (index != (_committed.size() - 1)) {
    return page_start(index + 1);
  }
  return _high_boundary;
}

void G1PageBasedVirtualSpace::commit_int(char* start, char* end) {
  guarantee(start >= _low_boundary && start < _high_boundary,
            err_msg("Start address " PTR_FORMAT" is outside of reserved space.", p2i(start)));
  guarantee(is_ptr_aligned(start, _commit_size),
            err_msg("Start address should be aligned to commit size " SIZE_FORMAT" but got " PTR_FORMAT".",
                    _commit_size, p2i(start)));

  guarantee(end >= _low_boundary && end <= _high_boundary,
            err_msg("End address " PTR_FORMAT" is outside of reserved space.", p2i(end)));
  bool is_high_aligned_to_commit_size = is_ptr_aligned(_high_boundary, _commit_size);
  guarantee(is_ptr_aligned(end, is_high_aligned_to_commit_size ? _commit_size : os::vm_page_size()),
            err_msg("End address should be aligned to page size " SIZE_FORMAT" but got " PTR_FORMAT".",
                    is_high_aligned_to_commit_size ? _commit_size : os::vm_page_size(),
                    p2i(end)));
  // First try to commit in commit_size chunks.
  char* const aligned_end_address = (char*)align_ptr_down(end, _commit_size);
  size_t const size = pointer_delta(aligned_end_address, start, sizeof(char));
  if (size != 0) {
    os::commit_memory_or_exit(start, size, _commit_size, _executable,
                              err_msg("Failed to commit area from " PTR_FORMAT" to " PTR_FORMAT" of length " SIZE_FORMAT".",
                                      p2i(start), p2i(aligned_end_address), size));
  }
  // Finally, commit any remaining tail.
  if (end != aligned_end_address) {
    size_t const tail_size = pointer_delta(end, aligned_end_address, sizeof(char));
    guarantee(tail_size < _commit_size,
              err_msg("Remaining size " SIZE_FORMAT "must be smaller than commit size of " SIZE_FORMAT, tail_size, _commit_size));
    os::commit_memory_or_exit(start, tail_size, _executable,
                              err_msg("Failed to commit remainder pages from " PTR_FORMAT" to " PTR_FORMAT" of length "SIZE_FORMAT".",
                                      p2i(aligned_end_address), p2i(end), tail_size));
  }
}

bool G1PageBasedVirtualSpace::commit(uintptr_t start, size_t size_in_pages) {
  // We need to make sure to commit all pages covered by the given area.
  guarantee(is_area_uncommitted(start, size_in_pages), "Specified area is not uncommitted");

  bool zero_filled = true;
  uintptr_t end = start + size_in_pages;

  if (_special) {
    // Check for dirty pages and update zero_filled if any found.
    if (_dirty.get_next_one_offset(start,end) < end) {
      zero_filled = false;
      _dirty.clear_range(start, end);
    }
  } else {
    commit_int(page_start(start), page_end(end - 1));
  }
  _committed.set_range(start, end);

  if (AlwaysPreTouch) {
    os::pretouch_memory(page_start(start), page_end(end - 1));
  }
  return zero_filled;
}

void G1PageBasedVirtualSpace::uncommit_int(char* start, char* end) {
  os::uncommit_memory(start, pointer_delta(end, start, sizeof(char)));
}

void G1PageBasedVirtualSpace::uncommit(uintptr_t start, size_t size_in_pages) {
  guarantee(is_area_committed(start, size_in_pages), "checking");

  uintptr_t end = start + size_in_pages;
  if (_special) {
    // Mark that memory is dirty. If committed again the memory might
    // need to be cleared explicitly.
    _dirty.set_range(start, end);
  } else {
    uncommit_int(page_start(start), page_end(end - 1));
  }

  _committed.clear_range(start, end);
}

bool G1PageBasedVirtualSpace::contains(const void* p) const {
  return _low_boundary <= (const char*) p && (const char*) p < _high_boundary;
}

#ifndef PRODUCT
void G1PageBasedVirtualSpace::print_on(outputStream* out) {
  out->print   ("Virtual space:");
  if (_special) out->print(" (pinned in memory)");
  out->cr();
  out->print_cr(" - committed: " SIZE_FORMAT, committed_size());
  out->print_cr(" - reserved:  " SIZE_FORMAT, reserved_size());
  out->print_cr(" - [low_b, high_b]: [" PTR_FORMAT", " PTR_FORMAT"]",  p2i(_low_boundary), p2i(_high_boundary));
}

void G1PageBasedVirtualSpace::print() {
  print_on(tty);
}
#endif