1 /*

     2  * Copyright (c) 2018, 2019, 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/g1/g1HeterogeneousCollectorPolicy.hpp"

    27 #include "logging/log.hpp"

    28 #include "runtime/globals_extension.hpp"

    29 #include "runtime/os.hpp"

    30 #include "utilities/formatBuffer.hpp"

    31 

    32 const double G1HeterogeneousCollectorPolicy::MaxRamFractionForYoung = 0.8;

    33 size_t G1HeterogeneousCollectorPolicy::MaxMemoryForYoung;

    34 

    35 static size_t calculate_reasonable_max_memory_for_young(FormatBuffer<100> &calc_str, double max_ram_fraction_for_young) {

    36   julong phys_mem;

    37   // If MaxRam is specified, we use that as maximum physical memory available.

    38   if (FLAG_IS_DEFAULT(MaxRAM)) {

    39     phys_mem = os::physical_memory();

    40     calc_str.append("Physical_Memory");

    41   } else {

    42     phys_mem = (julong)MaxRAM;

    43     calc_str.append("MaxRAM");

    44   }

    45 

    46   julong reasonable_max = phys_mem;

    47 

    48   // If either MaxRAMFraction or MaxRAMPercentage is specified, we use them to calculate

    49   // reasonable max size of young generation.

    50   if (!FLAG_IS_DEFAULT(MaxRAMFraction)) {

    51     reasonable_max = (julong)(phys_mem / MaxRAMFraction);

    52     calc_str.append(" / MaxRAMFraction");

    53   }  else if (!FLAG_IS_DEFAULT(MaxRAMPercentage)) {

    54     reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);

    55     calc_str.append(" * MaxRAMPercentage / 100");

    56   }  else {

    57     // We use our own fraction to calculate max size of young generation.

    58     reasonable_max = phys_mem * max_ram_fraction_for_young;

    59     calc_str.append(" * %0.2f", max_ram_fraction_for_young);

    60   }

    61 

    62   return (size_t)reasonable_max;

    63 }

    64 

    65 void G1HeterogeneousCollectorPolicy::initialize_flags() {

    66 

    67   FormatBuffer<100> calc_str("");

    68 

    69   MaxMemoryForYoung = calculate_reasonable_max_memory_for_young(calc_str, MaxRamFractionForYoung);

    70 

    71   if (MaxNewSize > MaxMemoryForYoung) {

    72     if (FLAG_IS_CMDLINE(MaxNewSize)) {

    73       log_warning(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",

    74                             MaxMemoryForYoung, calc_str.buffer());

    75     } else {

    76       log_info(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s)). "

    77                          "Dram usage can be lowered by setting MaxNewSize to a lower value", MaxMemoryForYoung, calc_str.buffer());

    78     }

    79     MaxNewSize = MaxMemoryForYoung;

    80   }

    81   if (NewSize > MaxMemoryForYoung) {

    82     if (FLAG_IS_CMDLINE(NewSize)) {

    83       log_warning(gc, ergo)("Setting NewSize to " SIZE_FORMAT " based on dram available (calculation = align(%s))",

    84                             MaxMemoryForYoung, calc_str.buffer());

    85     }

    86     NewSize = MaxMemoryForYoung;

    87   }

    88 

    89   // After setting new size flags, call base class initialize_flags()

    90   G1CollectorPolicy::initialize_flags();

    91 }

    92 

    93 size_t G1HeterogeneousCollectorPolicy::reasonable_max_memory_for_young() {

    94   return MaxMemoryForYoung;

    95 }

    96 

    97 size_t G1HeterogeneousCollectorPolicy::heap_reserved_size_bytes() const {

    98     return 2 * _max_heap_byte_size;

    99 }

   100 

   101 bool G1HeterogeneousCollectorPolicy::is_heterogeneous_heap() const {

   102   return true;

   103 }