1 /*

     2  * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #include "precompiled.hpp"

    26 #include "gc/parallel/generationSizer.hpp"

    27 #include "gc/shared/collectorPolicy.hpp"

    28 #include "runtime/globals_extension.hpp"

    29 #include "utilities/align.hpp"

    30 #include "utilities/globalDefinitions.hpp"

    31 

    32 void GenerationSizer::initialize_alignments() {

    33   _space_alignment = _gen_alignment = default_gen_alignment();

    34   _heap_alignment = compute_heap_alignment();

    35 }

    36 

    37 void GenerationSizer::initialize_flags() {

    38   // Do basic sizing work

    39   GenCollectorPolicy::initialize_flags();

    40 

    41   // The survivor ratio's are calculated "raw", unlike the

    42   // default gc, which adds 2 to the ratio value. We need to

    43   // make sure the values are valid before using them.

    44   if (MinSurvivorRatio < 3) {

    45     FLAG_SET_ERGO(uintx, MinSurvivorRatio, 3);

    46   }

    47 

    48   if (InitialSurvivorRatio < 3) {

    49     FLAG_SET_ERGO(uintx, InitialSurvivorRatio, 3);

    50   }

    51 }

    52 

    53 void GenerationSizer::initialize_size_info() {

    54   const size_t max_page_sz = os::page_size_for_region_aligned(_max_heap_byte_size, 8);

    55   const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old

    56   const size_t min_page_sz = os::page_size_for_region_aligned(_min_heap_byte_size, min_pages);

    57   const size_t page_sz = MIN2(max_page_sz, min_page_sz);

    58 

    59   // Can a page size be something else than a power of two?

    60   assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");

    61   size_t new_alignment = align_up(page_sz, _gen_alignment);

    62   if (new_alignment != _gen_alignment) {

    63     _gen_alignment = new_alignment;

    64     _space_alignment = new_alignment;

    65     // Redo everything from the start

    66     initialize_flags();

    67   }

    68   GenCollectorPolicy::initialize_size_info();

    69 }

    70 

    71 bool GenerationSizer::is_hetero_heap() const {

    72   return false;

    73 }

    74 

    75 size_t GenerationSizer::heap_reserved_size_bytes() const {

    76   return _max_heap_byte_size;

    77 }