/*

 * 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 "runtime/os.hpp"

#include "unittest.hpp"

static size_t small_page_size() {

  return os::vm_page_size();

}

static size_t large_page_size() {

  const size_t large_page_size_example = 4 * M;

  return os::page_size_for_region_aligned(large_page_size_example, 1);

}

TEST_VM(os, page_size_for_region) {

  size_t large_page_example = 4 * M;

  size_t large_page = os::page_size_for_region_aligned(large_page_example, 1);

  size_t small_page = os::vm_page_size();

  if (large_page > small_page) {

    size_t num_small_in_large = large_page / small_page;

    size_t page = os::page_size_for_region_aligned(large_page, num_small_in_large);

    ASSERT_EQ(page, small_page) << "Did not get a small page";

  }

}

TEST_VM(os, page_size_for_region_aligned) {

  if (UseLargePages) {

    const size_t small_page = small_page_size();

    const size_t large_page = large_page_size();

    if (large_page > small_page) {

      size_t num_small_pages_in_large = large_page / small_page;

      size_t page = os::page_size_for_region_aligned(large_page, num_small_pages_in_large);

      ASSERT_EQ(page, small_page);

    }

  }

}

TEST_VM(os, page_size_for_region_alignment) {

  if (UseLargePages) {

    const size_t small_page = small_page_size();

    const size_t large_page = large_page_size();

    if (large_page > small_page) {

      const size_t unaligned_region = large_page + 17;

      size_t page = os::page_size_for_region_aligned(unaligned_region, 1);

      ASSERT_EQ(page, small_page);

      const size_t num_pages = 5;

      const size_t aligned_region = large_page * num_pages;

      page = os::page_size_for_region_aligned(aligned_region, num_pages);

      ASSERT_EQ(page, large_page);

    }

  }

}

TEST_VM(os, page_size_for_region_unaligned) {

  if (UseLargePages) {

    // Given exact page size, should return that page size.

    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {

      size_t expected = os::_page_sizes[i];

      size_t actual = os::page_size_for_region_unaligned(expected, 1);

      ASSERT_EQ(expected, actual);

    }

    // Given slightly larger size than a page size, return the page size.

    for (size_t i = 0; os::_page_sizes[i] != 0; i++) {

      size_t expected = os::_page_sizes[i];

      size_t actual = os::page_size_for_region_unaligned(expected + 17, 1);

      ASSERT_EQ(expected, actual);

    }

    // Given a slightly smaller size than a page size,

    // return the next smaller page size.

    if (os::_page_sizes[1] > os::_page_sizes[0]) {

      size_t expected = os::_page_sizes[0];

      size_t actual = os::page_size_for_region_unaligned(os::_page_sizes[1] - 17, 1);

      ASSERT_EQ(actual, expected);

    }

    // Return small page size for values less than a small page.

    size_t small_page = small_page_size();

    size_t actual = os::page_size_for_region_unaligned(small_page - 17, 1);

    ASSERT_EQ(small_page, actual);

  }

}

#ifdef ASSERT

TEST_VM_ASSERT_MSG(os, page_size_for_region_with_zero_min_pages, "sanity") {

  size_t region_size = 16 * os::vm_page_size();

  os::page_size_for_region_aligned(region_size, 0); // should assert

}

#endif