/*

 * Copyright (c) 1997, 2014, 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"

PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC

// 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, 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(), 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();

}

/*

   First we need to determine if a particular virtual space is using large

   pages.  This is done at the initialize function and only virtual spaces

   that are larger than LargePageSizeInBytes use large pages.  Once we

   have determined this, all expand_by and shrink_by calls must grow and

   shrink by large page size chunks.  If a particular request

   is within the current large page, the call to commit and uncommit memory

   can be ignored.  In the case that the low and high boundaries of this

   space is not large page aligned, the pages leading to the first large

   page address and the pages after the last large page address must be

   allocated with default pages.

*/

bool VirtualSpace::expand_by(size_t bytes, bool pre_touch) {