/*

 * Copyright (c) 1997, 2013, 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 "oops/markOop.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/virtualspace.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

// ReservedSpace

// Dummy constructor

ReservedSpace::ReservedSpace() : _base(NULL), _size(0), _noaccess_prefix(0),

    _alignment(0), _special(false), _executable(false) {

}

ReservedSpace::ReservedSpace(size_t size) {

  size_t page_size = os::page_size_for_region(size, size, 1);

  bool large_pages = page_size != (size_t)os::vm_page_size();

  // Don't force the alignment to be large page aligned,

  // since that will waste memory.

  size_t alignment = os::vm_allocation_granularity();

  initialize(size, alignment, large_pages, NULL, 0, false);

}

ReservedSpace::ReservedSpace(size_t size, size_t alignment,

                             bool large,

                             char* requested_address,

                             const size_t noaccess_prefix) {

  initialize(size+noaccess_prefix, alignment, large, requested_address,

             noaccess_prefix, false);

}

ReservedSpace::ReservedSpace(size_t size, size_t alignment,

                             bool large,

                             bool executable) {

  initialize(size, alignment, large, NULL, 0, executable);

}

// Helper method.

static bool failed_to_reserve_as_requested(char* base, char* requested_address,

                                           const size_t size, bool special)

{

  if (base == requested_address || requested_address == NULL)

    return false; // did not fail

  if (base != NULL) {

    // Different reserve address may be acceptable in other cases

    // but for compressed oops heap should be at requested address.

    assert(UseCompressedOops, "currently requested address used only for compressed oops");

    if (PrintCompressedOopsMode) {

      tty->cr();

      tty->print_cr("Reserved memory not at requested address: " PTR_FORMAT " vs " PTR_FORMAT, base, requested_address);

    }

    // OS ignored requested address. Try different address.

    if (special) {

      if (!os::release_memory_special(base, size)) {

        fatal("os::release_memory_special failed");

      }

    } else {

      if (!os::release_memory(base, size)) {

        fatal("os::release_memory failed");

      }

    }

  }

  return true;

}

void ReservedSpace::initialize(size_t size, size_t alignment, bool large,

                               char* requested_address,

                               const size_t noaccess_prefix,

                               bool executable) {

  const size_t granularity = os::vm_allocation_granularity();

  assert((size & (granularity - 1)) == 0,

         "size not aligned to os::vm_allocation_granularity()");

  assert((alignment & (granularity - 1)) == 0,

         "alignment not aligned to os::vm_allocation_granularity()");

  assert(alignment == 0 || is_power_of_2((intptr_t)alignment),

         "not a power of 2");

  alignment = MAX2(alignment, (size_t)os::vm_page_size());

  // Assert that if noaccess_prefix is used, it is the same as alignment.

  assert(noaccess_prefix == 0 ||

         noaccess_prefix == alignment, "noaccess prefix wrong");

  _base = NULL;

  _size = 0;

  _special = false;

  _executable = executable;

  _alignment = 0;

  _noaccess_prefix = 0;

  if (size == 0) {

    return;

  }

  // If OS doesn't support demand paging for large page memory, we need

  // to use reserve_memory_special() to reserve and pin the entire region.

  bool special = large && !os::can_commit_large_page_memory();

  char* base = NULL;

  if (requested_address != 0) {

    requested_address -= noaccess_prefix; // adjust requested address

    assert(requested_address != NULL, "huge noaccess prefix?");

  }

  if (special) {

    base = os::reserve_memory_special(size, alignment, requested_address, executable);

    if (base != NULL) {

      if (failed_to_reserve_as_requested(base, requested_address, size, true)) {

        // OS ignored requested address. Try different address.

        return;

      }

      // Check alignment constraints.

      assert((uintptr_t) base % alignment == 0,

             err_msg("Large pages returned a non-aligned address, base: "

                 PTR_FORMAT " alignment: " PTR_FORMAT,

                 base, (void*)(uintptr_t)alignment));

      _special = true;

    } else {

      // failed; try to reserve regular memory below

      if (UseLargePages && (!FLAG_IS_DEFAULT(UseLargePages) ||

                            !FLAG_IS_DEFAULT(LargePageSizeInBytes))) {

        if (PrintCompressedOopsMode) {

          tty->cr();

          tty->print_cr("Reserve regular memory without large pages.");

        }

      }

    }

  }

  if (base == NULL) {

    // Optimistically assume that the OSes returns an aligned base pointer.

    // When reserving a large address range, most OSes seem to align to at

    // least 64K.

    // If the memory was requested at a particular address, use

    // os::attempt_reserve_memory_at() to avoid over mapping something

    // important.  If available space is not detected, return NULL.

    if (requested_address != 0) {

      base = os::attempt_reserve_memory_at(size, requested_address);

      if (failed_to_reserve_as_requested(base, requested_address, size, false)) {

        // OS ignored requested address. Try different address.

        base = NULL;

      }

    } else {

      base = os::reserve_memory(size, NULL, alignment);

    }

    if (base == NULL) return;

    // Check alignment constraints

    if ((((size_t)base + noaccess_prefix) & (alignment - 1)) != 0) {

      // Base not aligned, retry

      if (!os::release_memory(base, size)) fatal("os::release_memory failed");

      // Make sure that size is aligned

      size = align_size_up(size, alignment);

      base = os::reserve_memory_aligned(size, alignment);

      if (requested_address != 0 &&

          failed_to_reserve_as_requested(base, requested_address, size, false)) {

        // As a result of the alignment constraints, the allocated base differs

        // from the requested address. Return back to the caller who can

        // take remedial action (like try again without a requested address).

        assert(_base == NULL, "should be");

        return;

      }

    }

  }

  // Done

  _base = base;

  _size = size;

  _alignment = alignment;

  _noaccess_prefix = noaccess_prefix;

  // Assert that if noaccess_prefix is used, it is the same as alignment.

  assert(noaccess_prefix == 0 ||

         noaccess_prefix == _alignment, "noaccess prefix wrong");

  assert(markOopDesc::encode_pointer_as_mark(_base)->decode_pointer() == _base,

         "area must be distinguishable from marks for mark-sweep");

  assert(markOopDesc::encode_pointer_as_mark(&_base[size])->decode_pointer() == &_base[size],

         "area must be distinguishable from marks for mark-sweep");

}

ReservedSpace::ReservedSpace(char* base, size_t size, size_t alignment,

                             bool special, bool executable) {

  assert((size % os::vm_allocation_granularity()) == 0,

         "size not allocation aligned");

  _base = base;

  _size = size;

  _alignment = alignment;

  _noaccess_prefix = 0;

  _special = special;

  _executable = executable;

}

ReservedSpace ReservedSpace::first_part(size_t partition_size, size_t alignment,

                                        bool split, bool realloc) {

  assert(partition_size <= size(), "partition failed");

  if (split) {

    os::split_reserved_memory(base(), size(), partition_size, realloc);

  }

  ReservedSpace result(base(), partition_size, alignment, special(),

                       executable());

  return result;

}

ReservedSpace

ReservedSpace::last_part(size_t partition_size, size_t alignment) {

  assert(partition_size <= size(), "partition failed");

  ReservedSpace result(base() + partition_size, size() - partition_size,

                       alignment, special(), executable());

  return result;

}

size_t ReservedSpace::page_align_size_up(size_t size) {

  return align_size_up(size, os::vm_page_size());

}

size_t ReservedSpace::page_align_size_down(size_t size) {

  return align_size_down(size, os::vm_page_size());

}

size_t ReservedSpace::allocation_align_size_up(size_t size) {

  return align_size_up(size, os::vm_allocation_granularity());

}

size_t ReservedSpace::allocation_align_size_down(size_t size) {

  return align_size_down(size, os::vm_allocation_granularity());

}

void ReservedSpace::release() {

  if (is_reserved()) {

    char *real_base = _base - _noaccess_prefix;

    const size_t real_size = _size + _noaccess_prefix;

    if (special()) {

      os::release_memory_special(real_base, real_size);

    } else{

      os::release_memory(real_base, real_size);

    }

    _base = NULL;

    _size = 0;

    _noaccess_prefix = 0;

    _special = false;

    _executable = false;

  }

}

void ReservedSpace::protect_noaccess_prefix(const size_t size) {

  assert( (_noaccess_prefix != 0) == (UseCompressedOops && _base != NULL &&

                                      (Universe::narrow_oop_base() != NULL) &&

                                      Universe::narrow_oop_use_implicit_null_checks()),

         "noaccess_prefix should be used only with non zero based compressed oops");

  // If there is no noaccess prefix, return.

  if (_noaccess_prefix == 0) return;

  assert(_noaccess_prefix >= (size_t)os::vm_page_size(),

         "must be at least page size big");

  // Protect memory at the base of the allocated region.

  // If special, the page was committed (only matters on windows)

  if (!os::protect_memory(_base, _noaccess_prefix, os::MEM_PROT_NONE,

                          _special)) {

    fatal("cannot protect protection page");

  }

  if (PrintCompressedOopsMode) {

    tty->cr();

    tty->print_cr("Protected page at the reserved heap base: " PTR_FORMAT " / " INTX_FORMAT " bytes", _base, _noaccess_prefix);

  }

  _base += _noaccess_prefix;

  _size -= _noaccess_prefix;

  assert((size == _size) && ((uintptr_t)_base % _alignment == 0),

         "must be exactly of required size and alignment");

}

ReservedHeapSpace::ReservedHeapSpace(size_t size, size_t alignment,

                                     bool large, char* requested_address) :

  ReservedSpace(size, alignment, large,

                requested_address,

                (UseCompressedOops && (Universe::narrow_oop_base() != NULL) &&

                 Universe::narrow_oop_use_implicit_null_checks()) ?

                  lcm(os::vm_page_size(), alignment) : 0) {

  if (base() > 0) {

    MemTracker::record_virtual_memory_type((address)base(), mtJavaHeap);

  }

  // Only reserved space for the java heap should have a noaccess_prefix

  // if using compressed oops.

  protect_noaccess_prefix(size);

}

// Reserve space for code segment.  Same as Java heap only we mark this as

// executable.

ReservedCodeSpace::ReservedCodeSpace(size_t r_size,

                                     size_t rs_align,

                                     bool large) :

  ReservedSpace(r_size, rs_align, large, /*executable*/ true) {

  MemTracker::record_virtual_memory_type((address)base(), mtCode);

}

// VirtualSpace

VirtualSpace::VirtualSpace() {

  _low_boundary           = NULL;

  _high_boundary          = NULL;

  _low                    = NULL;

  _high                   = NULL;

  _lower_high             = NULL;

  _middle_high            = NULL;

  _upper_high             = NULL;

  _lower_high_boundary    = NULL;

  _middle_high_boundary   = NULL;

  _upper_high_boundary    = NULL;

  _lower_alignment        = 0;

  _middle_alignment       = 0;

  _upper_alignment        = 0;

  _special                = false;

  _executable             = false;

}

bool VirtualSpace::initialize(ReservedSpace rs, size_t committed_size) {

  const size_t max_commit_granularity = os::page_size_for_region(rs.size(), rs.size(), 1);

  return initialize_with_granularity(rs, committed_size, max_commit_granularity);

}

bool VirtualSpace::initialize_with_granularity(ReservedSpace rs, size_t committed_size, size_t max_commit_granularity) {

  if(!rs.is_reserved()) return false;  // allocation failed.

  assert(_low_boundary == NULL, "VirtualSpace already initialized");

  assert(max_commit_granularity > 0, "Granularity must be non-zero.");

  _low_boundary  = rs.base();

  _high_boundary = low_boundary() + rs.size();

  _low = low_boundary();

  _high = low();

  _special = rs.special();

  _executable = rs.executable();

  // When a VirtualSpace begins life at a large size, make all future expansion

  // and shrinking occur aligned to a granularity of large pages.  This avoids

  // fragmentation of physical addresses that inhibits the use of large pages

  // by the OS virtual memory system.  Empirically,  we see that with a 4MB

  // page size, the only spaces that get handled this way are codecache and

  // the heap itself, both of which provide a substantial performance

  // boost in many benchmarks when covered by large pages.

  //

  // No attempt is made to force large page alignment at the very top and

  // bottom of the space if they are not aligned so already.

  _lower_alignment  = os::vm_page_size();

  _middle_alignment = max_commit_granularity;

  _upper_alignment  = os::vm_page_size();

  // End of each region

  _lower_high_boundary = (char*) round_to((intptr_t) low_boundary(), middle_alignment());

  _middle_high_boundary = (char*) round_down((intptr_t) high_boundary(), middle_alignment());

  _upper_high_boundary = high_boundary();

  // High address of each region

  _lower_high = low_boundary();

  _middle_high = lower_high_boundary();

  _upper_high = middle_high_boundary();

  // commit to initial size

  if (committed_size > 0) {

    if (!expand_by(committed_size)) {

      return false;

    }

  }

  return true;

}

VirtualSpace::~VirtualSpace() {

  release();

}

void VirtualSpace::release() {

  // This does not release memory it never reserved.

  // Caller must release via rs.release();

  _low_boundary           = NULL;

  _high_boundary          = NULL;

  _low                    = NULL;

  _high                   = NULL;

  _lower_high             = NULL;

  _middle_high            = NULL;

  _upper_high             = NULL;

  _lower_high_boundary    = NULL;

  _middle_high_boundary   = NULL;

  _upper_high_boundary    = NULL;

  _lower_alignment        = 0;

  _middle_alignment       = 0;

  _upper_alignment        = 0;

  _special                = false;

  _executable             = false;

}

size_t VirtualSpace::committed_size() const {

  return pointer_delta(high(), low(), sizeof(char));

}

size_t VirtualSpace::reserved_size() const {

  return pointer_delta(high_boundary(), low_boundary(), sizeof(char));

}

size_t VirtualSpace::uncommitted_size()  const {

  return reserved_size() - committed_size();

}

size_t VirtualSpace::actual_committed_size() const {

  // Special VirtualSpaces commit all reserved space up front.

  if (special()) {

    return reserved_size();

  }

  size_t committed_low    = pointer_delta(_lower_high,  _low_boundary,         sizeof(char));

  size_t committed_middle = pointer_delta(_middle_high, _lower_high_boundary,  sizeof(char));

  size_t committed_high   = pointer_delta(_upper_high,  _middle_high_boundary, sizeof(char));

#ifdef ASSERT

  size_t lower  = pointer_delta(_lower_high_boundary,  _low_boundary,         sizeof(char));

  size_t middle = pointer_delta(_middle_high_boundary, _lower_high_boundary,  sizeof(char));

  size_t upper  = pointer_delta(_upper_high_boundary,  _middle_high_boundary, sizeof(char));

  if (committed_high > 0) {

    assert(committed_low == lower, "Must be");

    assert(committed_middle == middle, "Must be");

  }

  if (committed_middle > 0) {

    assert(committed_low == lower, "Must be");

  }

  if (committed_middle < middle) {

    assert(committed_high == 0, "Must be");

  }

  if (committed_low < lower) {

    assert(committed_high == 0, "Must be");

    assert(committed_middle == 0, "Must be");

  }

#endif

  return committed_low + committed_middle + committed_high;

}

bool VirtualSpace::contains(const void* p) const {

  return low() <= (const char*) p && (const char*) p < high();