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 /*

  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.

  * 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

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  */

 #include "precompiled.hpp"

 #include "gc_implementation/parallelScavenge/adjoiningGenerations.hpp"

 #include "gc_implementation/parallelScavenge/adjoiningVirtualSpaces.hpp"

 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"

 #include "gc_implementation/parallelScavenge/psPermGen.hpp"

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

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

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

 AdjoiningGenerations::AdjoiningGenerations(ReservedSpace old_young_rs,

                                            size_t init_low_byte_size,

                                            size_t min_low_byte_size,

                                            size_t max_low_byte_size,

                                            size_t init_high_byte_size,

                                            size_t min_high_byte_size,

                                            size_t max_high_byte_size,

                                            size_t alignment) :

   _virtual_spaces(old_young_rs, min_low_byte_size,

                   min_high_byte_size, alignment) {

   assert(min_low_byte_size <= init_low_byte_size &&

          init_low_byte_size <= max_low_byte_size, "Parameter check");

   assert(min_high_byte_size <= init_high_byte_size &&

          init_high_byte_size <= max_high_byte_size, "Parameter check");

   // Create the generations differently based on the option to

   // move the boundary.

   if (UseAdaptiveGCBoundary) {

     // Initialize the adjoining virtual spaces.  Then pass the

     // a virtual to each generation for initialization of the

     // generation.

     // Does the actual creation of the virtual spaces

     _virtual_spaces.initialize(max_low_byte_size,

                                init_low_byte_size,

                                init_high_byte_size);

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

     _young_gen = new ASPSYoungGen(_virtual_spaces.high(),

                                   _virtual_spaces.high()->committed_size(),

                                   min_high_byte_size,

                                   _virtual_spaces.high_byte_size_limit());

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

     _old_gen = new ASPSOldGen(_virtual_spaces.low(),

                               _virtual_spaces.low()->committed_size(),

                               min_low_byte_size,

                               _virtual_spaces.low_byte_size_limit(),

                               "old", 1);

     young_gen()->initialize_work();

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

      "Consistency check");

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

      "Consistency check");

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

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

      "Consistency check");

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

      "Consistency check");

   } else {

     // Layout the reserved space for the generations.

     ReservedSpace old_rs   =

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

     ReservedSpace heap_rs  =

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

     ReservedSpace young_rs = heap_rs.first_part(max_high_byte_size);

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

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

     _young_gen = new PSYoungGen(init_high_byte_size,

                                 min_high_byte_size,

                                 max_high_byte_size);

     _old_gen = new PSOldGen(init_low_byte_size,

                             min_low_byte_size,

                             max_low_byte_size,

                             "old", 1);

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

     _young_gen->initialize(young_rs, alignment);

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

       "Consistency check");

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

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

   }

 }

 size_t AdjoiningGenerations::reserved_byte_size() {

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

 }

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

 // the contraints on the sizes of the generations.  Push

 // up the boundary within the contraints.  A partial

 // push can occur.

 void AdjoiningGenerations::request_old_gen_expansion(size_t expand_in_bytes) {

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

   assert_lock_strong(ExpandHeap_lock);

   assert_locked_or_safepoint(Heap_lock);

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

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

   // generation.

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

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

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

   size_t change_in_bytes = MIN3(young_gen_available,

                                 old_gen_available,

                                 align_size_up_(expand_in_bytes, alignment));

   if (change_in_bytes == 0) {

     return;

   }

   if (TraceAdaptiveGCBoundary) {

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

     gclog_or_tty->print_cr("  Requested change: 0x%x  Attempted change: 0x%x",

       expand_in_bytes, change_in_bytes);

     if (!PrintHeapAtGC) {

       Universe::print_on(gclog_or_tty);

     }

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

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

   }

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

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

     young_gen()->reset_after_change();

     old_gen()->reset_after_change();

   }

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

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

   assert(reserved_byte_size() ==

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

          "Space is missing");

   young_gen()->space_invariants();

   old_gen()->space_invariants();

   if (TraceAdaptiveGCBoundary) {

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

     if (!PrintHeapAtGC) {

       Universe::print_on(gclog_or_tty);

     }

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

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

   }

 }

 // See comments on request_old_gen_expansion()

 bool AdjoiningGenerations::request_young_gen_expansion(size_t expand_in_bytes) {

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

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

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

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

     return false;

   }

   bool result = false;

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

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

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

   size_t change_in_bytes = MIN3(young_gen_available,

                                 old_gen_available,

                                 align_size_up_(expand_in_bytes, alignment));

   if (change_in_bytes == 0) {

     return false;

   }

   if (TraceAdaptiveGCBoundary) {

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

     gclog_or_tty->print_cr("  Requested change: 0x%x  Attempted change: 0x%x",

       expand_in_bytes, change_in_bytes);

     if (!PrintHeapAtGC) {

       Universe::print_on(gclog_or_tty);

     }

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

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

   }

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

   MutexLocker x(ExpandHeap_lock);

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

     young_gen()->reset_after_change();

     old_gen()->reset_after_change();

     result = true;

   }

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

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

   assert(reserved_byte_size() ==

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

          "Space is missing");

   young_gen()->space_invariants();

   old_gen()->space_invariants();

   if (TraceAdaptiveGCBoundary) {

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

     if (!PrintHeapAtGC) {

       Universe::print_on(gclog_or_tty);

     }

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

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

   }

   return result;

 }

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

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

 void AdjoiningGenerations::adjust_boundary_for_old_gen_needs(

   size_t desired_free_space) {

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

   // Stress testing.

   if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 1) {

     MutexLocker x(ExpandHeap_lock);

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

   }

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

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

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

       MutexLocker x(ExpandHeap_lock);

       request_old_gen_expansion(desired_free_space);

     }

   }

 }

 // See comment on adjust_boundary_for_old_gen_needss().

 // Adjust boundary down only.

 void AdjoiningGenerations::adjust_boundary_for_young_gen_needs(size_t eden_size,

     size_t survivor_size) {

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

   // Stress testing.

   if (PSAdaptiveSizePolicyResizeVirtualSpaceAlot == 0) {

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

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

   }

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

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

     size_t desired_size = eden_size + 2 * survivor_size;

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

     if (desired_size > committed) {

       request_young_gen_expansion(desired_size - committed);

     }

   }

 }