1 /*
   2  * Copyright (c) 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/g1/g1HeterogeneousCollectorPolicy.hpp"
  27 
  28 const double G1HeterogeneousCollectorPolicy::MaxRamFractionForYoung = 0.8;
  29 
  30 void G1HeterogeneousCollectorPolicy::initialize_flags() {
  31 
  32   size_t reasonable_max = reasonable_max_memory_for_young();
  33 
  34   if (MaxNewSize > reasonable_max) {
  35     if (FLAG_IS_CMDLINE(MaxNewSize)) {
  36       log_warning(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " based on dram memory available", reasonable_max);
  37     } else {
  38       log_info(gc, ergo)("Setting MaxNewSize to " SIZE_FORMAT " which is 80%% of dram memory. Dram usage can be lowered by setting MaxNewSize to a lower value", (size_t)reasonable_max);
  39     }
  40     MaxNewSize = reasonable_max;
  41   }
  42   if (NewSize > reasonable_max) {
  43     if (FLAG_IS_CMDLINE(NewSize)) {
  44       log_warning(gc, ergo)("Setting NewSize to " SIZE_FORMAT " based on dram memory available", reasonable_max);
  45     }
  46     NewSize = reasonable_max;
  47   }
  48 
  49   // After setting new size flags, call base class initialize_flags()
  50   G1CollectorPolicy::initialize_flags();
  51 }
  52 
  53 size_t G1HeterogeneousCollectorPolicy::reasonable_max_memory_for_young() {
  54   julong young_size_limit = os::physical_memory();
  55 
  56   // If MaxRam is specified, we use that as maximum physical memory available.
  57   julong phys_mem = FLAG_IS_DEFAULT(MaxRAM) ? os::physical_memory() : (julong)MaxRAM;
  58 
  59   julong reasonable_max = phys_mem;
  60 
  61   // If either MaxRAMFraction or MaxRAMPercentage is specified, we use them to calculate 
  62   // reasonable max size of young generation.
  63   if (!FLAG_IS_DEFAULT(MaxRAMFraction)) {
  64     reasonable_max = (julong)(phys_mem / MaxRAMFraction);
  65   } else if (!FLAG_IS_DEFAULT(MaxRAMPercentage)) {
  66     reasonable_max = (julong)((phys_mem * MaxRAMPercentage) / 100);
  67   } else {
  68     // We use our own fraction to calculate max size of young generation.
  69     reasonable_max = phys_mem * MaxRamFractionForYoung;
  70   }
  71   return (size_t)reasonable_max;
  72 }
  73 
  74 size_t G1HeterogeneousCollectorPolicy::heap_reserved_size_bytes() const {
  75     return 2 * _max_heap_byte_size;
  76 }
  77 
  78 bool G1HeterogeneousCollectorPolicy::is_hetero_heap() const {
  79   return true;
  80 }