/*

 * Copyright 1997-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#include "incls/_precompiled.incl"

#include "incls/_virtualspace.cpp.incl"

// ReservedSpace

ReservedSpace::ReservedSpace(size_t size) {

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

}

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);

}

char *

ReservedSpace::align_reserved_region(char* addr, const size_t len,

                                     const size_t prefix_size,

                                     const size_t prefix_align,

                                     const size_t suffix_size,

                                     const size_t suffix_align)

{

  assert(addr != NULL, "sanity");

  const size_t required_size = prefix_size + suffix_size;

  assert(len >= required_size, "len too small");

  const size_t s = size_t(addr);

  const size_t beg_ofs = s + prefix_size & suffix_align - 1;

  const size_t beg_delta = beg_ofs == 0 ? 0 : suffix_align - beg_ofs;

  if (len < beg_delta + required_size) {

     return NULL; // Cannot do proper alignment.

  }

  const size_t end_delta = len - (beg_delta + required_size);

  if (beg_delta != 0) {

    os::release_memory(addr, beg_delta);

  }

  if (end_delta != 0) {

    char* release_addr = (char*) (s + beg_delta + required_size);

    os::release_memory(release_addr, end_delta);

  }

  return (char*) (s + beg_delta);

}

char* ReservedSpace::reserve_and_align(const size_t reserve_size,

                                       const size_t prefix_size,

                                       const size_t prefix_align,

                                       const size_t suffix_size,

                                       const size_t suffix_align)

{

  assert(reserve_size > prefix_size + suffix_size, "should not be here");

  char* raw_addr = os::reserve_memory(reserve_size, NULL, prefix_align);

  if (raw_addr == NULL) return NULL;

  char* result = align_reserved_region(raw_addr, reserve_size, prefix_size,

                                       prefix_align, suffix_size,

                                       suffix_align);

  if (result == NULL && !os::release_memory(raw_addr, reserve_size)) {

    fatal("os::release_memory failed");

  }

#ifdef ASSERT

  if (result != NULL) {

    const size_t raw = size_t(raw_addr);

    const size_t res = size_t(result);

    assert(res >= raw, "alignment decreased start addr");

    assert(res + prefix_size + suffix_size <= raw + reserve_size,

           "alignment increased end addr");

    assert((res & prefix_align - 1) == 0, "bad alignment of prefix");

    assert((res + prefix_size & suffix_align - 1) == 0,

           "bad alignment of suffix");

  }

#endif

  return result;

}

ReservedSpace::ReservedSpace(const size_t prefix_size,

                             const size_t prefix_align,

                             const size_t suffix_size,

                             const size_t suffix_align,

                             const size_t noaccess_prefix)

{

  assert(prefix_size != 0, "sanity");

  assert(prefix_align != 0, "sanity");

  assert(suffix_size != 0, "sanity");

  assert(suffix_align != 0, "sanity");

  assert((prefix_size & prefix_align - 1) == 0,

    "prefix_size not divisible by prefix_align");

  assert((suffix_size & suffix_align - 1) == 0,

    "suffix_size not divisible by suffix_align");

  assert((suffix_align & prefix_align - 1) == 0,

    "suffix_align not divisible by prefix_align");

  // Add in noaccess_prefix to prefix_size;

  const size_t adjusted_prefix_size = prefix_size + noaccess_prefix;

  const size_t size = adjusted_prefix_size + suffix_size;

  // On systems where the entire region has to be reserved and committed up

  // front, the compound alignment normally done by this method is unnecessary.

  const bool try_reserve_special = UseLargePages &&

    prefix_align == os::large_page_size();

  if (!os::can_commit_large_page_memory() && try_reserve_special) {

    return;

  }

  _base = NULL;

  _size = 0;

  _alignment = 0;

  _special = false;

  _noaccess_prefix = 0;

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

  assert(noaccess_prefix == 0 ||

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

  // Optimistically try to reserve the exact size needed.

  if (addr == NULL) return;

  // Check whether the result has the needed alignment (unlikely unless

  // prefix_align == suffix_align).

  const size_t ofs = size_t(addr) + adjusted_prefix_size & suffix_align - 1;

  if (ofs != 0) {

    // Wrong alignment.  Release, allocate more space and do manual alignment.

    //

    // On most operating systems, another allocation with a somewhat larger size

    // will return an address "close to" that of the previous allocation.  The

    // result is often the same address (if the kernel hands out virtual

    // addresses from low to high), or an address that is offset by the increase

    // in size.  Exploit that to minimize the amount of extra space requested.

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

      fatal("os::release_memory failed");

    }

    const size_t extra = MAX2(ofs, suffix_align - ofs);

    addr = reserve_and_align(size + extra, adjusted_prefix_size, prefix_align,

                             suffix_size, suffix_align);

    if (addr == NULL) {

      // Try an even larger region.  If this fails, address space is exhausted.

      addr = reserve_and_align(size + suffix_align, adjusted_prefix_size,

                               prefix_align, suffix_size, suffix_align);

    }

  }

  _base = addr;

  _size = size;

  _alignment = prefix_align;

  _noaccess_prefix = noaccess_prefix;

}

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

                               char* requested_address,

                               const size_t noaccess_prefix) {

  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");

  _base = NULL;

  _size = 0;

  _special = false;

  _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 (special) {

    if (base != NULL) {

      // Check alignment constraints

      if (alignment > 0) {

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

               "Large pages returned a non-aligned address");

      }

      _special = true;

    } else {

      // failed; try to reserve regular memory below

    }

  }

  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-noaccess_prefix);

    } else {

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

    }

    if (base == NULL) return;

    // Check alignment constraints

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

      // Base not aligned, retry

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

      // Reserve size large enough to do manual alignment and

      // increase size to a multiple of the desired alignment

      size = align_size_up(size, alignment);

      size_t extra_size = size + alignment;

      do {

        char* extra_base = os::reserve_memory(extra_size, NULL, alignment);

        if (extra_base == NULL) return;

        // Do manual alignement

        base = (char*) align_size_up((uintptr_t) extra_base, alignment);

        assert(base >= extra_base, "just checking");

        // Re-reserve the region at the aligned base address.

        os::release_memory(extra_base, extra_size);

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

      } while (base == NULL);

    }

  }

  // Done

  _base = base;

  _size = size;

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

  _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 distinguisable from marks for mark-sweep");

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

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

}

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

                             bool special) {

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

         "size not allocation aligned");

  _base = base;

  _size = size;

  _alignment = alignment;

  _noaccess_prefix = 0;

  _special = special;

}

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());

  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());

  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;

  }

}

void ReservedSpace::protect_noaccess_prefix(const size_t size) {

  // If there is 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");

  }

  _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,

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

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

  // if using compressed oops.

  protect_noaccess_prefix(size);

}

ReservedHeapSpace::ReservedHeapSpace(const size_t prefix_size,

                                     const size_t prefix_align,

                                     const size_t suffix_size,

  ReservedSpace(prefix_size, prefix_align, suffix_size, suffix_align,

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

  protect_noaccess_prefix(prefix_size+suffix_size);

}

// 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;

}

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

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

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

  _low_boundary  = rs.base();

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

  _low = low_boundary();

  _high = low();

  _special = rs.special();

  // 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 = os::page_size_for_region(rs.size(), rs.size(), 1);

  _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;

}

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();

}

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