1 /*

     2  * Copyright (c) 2003, 2015, 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/adjoiningGenerations.hpp"

    27 #include "gc/parallel/adjoiningVirtualSpaces.hpp"

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

    29 #include "gc/parallel/parallelScavengeHeap.hpp"

    30 

    31 // If boundary moving is being used, create the young gen and old

    32 // gen with ASPSYoungGen and ASPSOldGen, respectively.  Revert to

    33 // the old behavior otherwise (with PSYoungGen and PSOldGen).

    34 

    35 AdjoiningGenerations::AdjoiningGenerations(ReservedSpace old_young_rs,

    36                                            GenerationSizer* policy,

    37                                            size_t alignment) :

    38   _virtual_spaces(old_young_rs, policy->min_old_size(),

    39                   policy->min_young_size(), alignment) {

    40   size_t init_low_byte_size = policy->initial_old_size();

    41   size_t min_low_byte_size = policy->min_old_size();

    42   size_t max_low_byte_size = policy->max_old_size();

    43   size_t init_high_byte_size = policy->initial_young_size();

    44   size_t min_high_byte_size = policy->min_young_size();

    45   size_t max_high_byte_size = policy->max_young_size();

    46 

    47   assert(min_low_byte_size <= init_low_byte_size &&

    48          init_low_byte_size <= max_low_byte_size, "Parameter check");

    49   assert(min_high_byte_size <= init_high_byte_size &&

    50          init_high_byte_size <= max_high_byte_size, "Parameter check");

    51   // Create the generations differently based on the option to

    52   // move the boundary.

    53   if (UseAdaptiveGCBoundary) {

    54     // Initialize the adjoining virtual spaces.  Then pass the

    55     // a virtual to each generation for initialization of the

    56     // generation.

    57 

    58     // Does the actual creation of the virtual spaces

    59     _virtual_spaces.initialize(max_low_byte_size,

    60                                init_low_byte_size,

    61                                init_high_byte_size);

    62 

    63     // Place the young gen at the high end.  Passes in the virtual space.

    64     _young_gen = new ASPSYoungGen(_virtual_spaces.high(),

    65                                   _virtual_spaces.high()->committed_size(),

    66                                   min_high_byte_size,

    67                                   _virtual_spaces.high_byte_size_limit());

    68 

    69     // Place the old gen at the low end. Passes in the virtual space.

    70     _old_gen = new ASPSOldGen(_virtual_spaces.low(),

    71                               _virtual_spaces.low()->committed_size(),

    72                               min_low_byte_size,

    73                               _virtual_spaces.low_byte_size_limit(),

    74                               "old", 1);

    75 

    76     young_gen()->initialize_work();

    77     assert(young_gen()->reserved().byte_size() <= young_gen()->gen_size_limit(),

    78      "Consistency check");

    79     assert(old_young_rs.size() >= young_gen()->gen_size_limit(),

    80      "Consistency check");

    81 

    82     old_gen()->initialize_work("old", 1);

    83     assert(old_gen()->reserved().byte_size() <= old_gen()->gen_size_limit(),

    84      "Consistency check");

    85     assert(old_young_rs.size() >= old_gen()->gen_size_limit(),

    86      "Consistency check");

    87   } else {

    88 

    89     // Layout the reserved space for the generations.

    90     ReservedSpace old_rs   =

    91       virtual_spaces()->reserved_space().first_part(max_low_byte_size);

    92     ReservedSpace heap_rs  =

    93       virtual_spaces()->reserved_space().last_part(max_low_byte_size);

    94     ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);

    95     assert(young_rs.size() == heap_rs.size(), "Didn't reserve all of the heap");

    96 

    97     // Create the generations.  Virtual spaces are not passed in.

    98     _young_gen = new PSYoungGen(init_high_byte_size,

    99                                 min_high_byte_size,

   100                                 max_high_byte_size);

   101     _old_gen = new PSOldGen(init_low_byte_size,

   102                             min_low_byte_size,

   103                             max_low_byte_size,

   104                             "old", 1);

   105 

   106     // The virtual spaces are created by the initialization of the gens.

   107     _young_gen->initialize(young_rs, alignment);

   108     assert(young_gen()->gen_size_limit() == young_rs.size(),

   109       "Consistency check");

   110     _old_gen->initialize(old_rs, alignment, "old", 1);

   111     assert(old_gen()->gen_size_limit() == old_rs.size(), "Consistency check");

   112   }

   113 }

   114 

   115 size_t AdjoiningGenerations::reserved_byte_size() {

   116   return virtual_spaces()->reserved_space().size();

   117 }

   118 

   119 

   120 // Make checks on the current sizes of the generations and

   121 // the constraints on the sizes of the generations.  Push

   122 // up the boundary within the constraints.  A partial

   123 // push can occur.

   124 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {

   125   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");

   126 

   127   assert_lock_strong(ExpandHeap_lock);

   128   assert_locked_or_safepoint(Heap_lock);

   129 

   130   // These sizes limit the amount the boundaries can move.  Effectively,

   131   // the generation says how much it is willing to yield to the other

   132   // generation.

   133   const size_t young_gen_available = young_gen()->available_for_contraction();

   134   const size_t old_gen_available = old_gen()->available_for_expansion();

   135   const size_t alignment = virtual_spaces()->alignment();

   136   size_t change_in_bytes = MIN3(young_gen_available,

   137                                 old_gen_available,

   138                                 align_size_up_(expand_in_bytes, alignment));

   139 

   140   if (change_in_bytes == 0) {

   141     return;

   142   }

   143 

   144   if (TraceAdaptiveGCBoundary) {

   145     gclog_or_tty->print_cr("Before expansion of old gen with boundary move");

   146     gclog_or_tty->print_cr("  Requested change: " SIZE_FORMAT_HEX

   147                            "  Attempted change: " SIZE_FORMAT_HEX,

   148       expand_in_bytes, change_in_bytes);

   149     if (!PrintHeapAtGC) {

   150       Universe::print_on(gclog_or_tty);

   151     }

   152     gclog_or_tty->print_cr("  PSOldGen max size: " SIZE_FORMAT "K",

   153       old_gen()->max_gen_size()/K);

   154   }

   155 

   156   // Move the boundary between the generations up (smaller young gen).

   157   if (virtual_spaces()->adjust_boundary_up(change_in_bytes)) {

   158     young_gen()->reset_after_change();

   159     old_gen()->reset_after_change();

   160   }

   161 

   162   // The total reserved for the generations should match the sum

   163   // of the two even if the boundary is moving.

   164   assert(reserved_byte_size() ==

   165          old_gen()->max_gen_size() + young_gen()->max_size(),

   166          "Space is missing");

   167   young_gen()->space_invariants();

   168   old_gen()->space_invariants();

   169 

   170   if (TraceAdaptiveGCBoundary) {

   171     gclog_or_tty->print_cr("After expansion of old gen with boundary move");

   172     if (!PrintHeapAtGC) {

   173       Universe::print_on(gclog_or_tty);

   174     }

   175     gclog_or_tty->print_cr("  PSOldGen max size: " SIZE_FORMAT "K",

   176       old_gen()->max_gen_size()/K);

   177   }

   178 }

   179 

   180 // See comments on request_old_gen_expansion()

   181 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {

   182   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");

   183 

   184   // If eden is not empty, the boundary can be moved but no advantage

   185   // can be made of the move since eden cannot be moved.

   186   if (!young_gen()->eden_space()->is_empty()) {

   187     return false;

   188   }

   189 

   190 

   191   bool result = false;

   192   const size_t young_gen_available = young_gen()->available_for_expansion();

   193   const size_t old_gen_available = old_gen()->available_for_contraction();

   194   const size_t alignment = virtual_spaces()->alignment();

   195   size_t change_in_bytes = MIN3(young_gen_available,

   196                                 old_gen_available,

   197                                 align_size_up_(expand_in_bytes, alignment));

   198 

   199   if (change_in_bytes == 0) {

   200     return false;

   201   }

   202 

   203   if (TraceAdaptiveGCBoundary) {

   204     gclog_or_tty->print_cr("Before expansion of young gen with boundary move");

   205     gclog_or_tty->print_cr("  Requested change: " SIZE_FORMAT_HEX "  Attempted change: " SIZE_FORMAT_HEX,

   206       expand_in_bytes, change_in_bytes);

   207     if (!PrintHeapAtGC) {

   208       Universe::print_on(gclog_or_tty);

   209     }

   210     gclog_or_tty->print_cr("  PSYoungGen max size: " SIZE_FORMAT "K",

   211       young_gen()->max_size()/K);

   212   }

   213 

   214   // Move the boundary between the generations down (smaller old gen).

   215   MutexLocker x(ExpandHeap_lock);

   216   if (virtual_spaces()->adjust_boundary_down(change_in_bytes)) {

   217     young_gen()->reset_after_change();

   218     old_gen()->reset_after_change();

   219     result = true;

   220   }

   221 

   222   // The total reserved for the generations should match the sum

   223   // of the two even if the boundary is moving.

   224   assert(reserved_byte_size() ==

   225          old_gen()->max_gen_size() + young_gen()->max_size(),

   226          "Space is missing");

   227   young_gen()->space_invariants();

   228   old_gen()->space_invariants();

   229 

   230   if (TraceAdaptiveGCBoundary) {

   231     gclog_or_tty->print_cr("After expansion of young gen with boundary move");

   232     if (!PrintHeapAtGC) {

   233       Universe::print_on(gclog_or_tty);

   234     }

   235     gclog_or_tty->print_cr("  PSYoungGen max size: " SIZE_FORMAT "K",

   236       young_gen()->max_size()/K);

   237   }

   238 

   239   return result;

   240 }

   241 

   242 // Additional space is needed in the old generation.  Try to move the boundary

   243 // up to meet the need.  Moves boundary up only

   244 void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(

   245   size_t desired_free_space) {

   246   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");

   247 

   248   // Stress testing.

   249   if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {

   250     MutexLocker x(ExpandHeap_lock);

   251     request_old_gen_expansion(virtual_spaces()->alignment() * 3 / 2);

   252   }

   253 

   254   // Expand only if the entire generation is already committed.

   255   if (old_gen()->virtual_space()->uncommitted_size() == 0) {

   256     if (old_gen()->free_in_bytes() < desired_free_space) {

   257       MutexLocker x(ExpandHeap_lock);

   258       request_old_gen_expansion(desired_free_space);

   259     }

   260   }

   261 }

   262 

   263 // See comment on adjust_boundary_for_old_gen_needss().

   264 // Adjust boundary down only.

   265 void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,

   266     size_t survivor_size) {

   267 

   268   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");

   269 

   270   // Stress testing.

   271   if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {

   272     request_young_gen_expansion(virtual_spaces()->alignment() * 3 / 2);

   273     eden_size = young_gen()->eden_space()->capacity_in_bytes();

   274   }

   275 

   276   // Expand only if the entire generation is already committed.

   277   if (young_gen()->virtual_space()->uncommitted_size() == 0) {

   278     size_t desired_size = eden_size + 2 * survivor_size;

   279     const size_t committed = young_gen()->virtual_space()->committed_size();

   280     if (desired_size > committed) {

   281       request_young_gen_expansion(desired_size - committed);

   282     }

   283   }

   284 }