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/asPSOldGen.hpp"
  27 #include "gc/parallel/parallelScavengeHeap.hpp"
  28 #include "gc/parallel/psAdaptiveSizePolicy.hpp"
  29 #include "gc/parallel/psMarkSweepDecorator.hpp"
  30 #include "gc/shared/cardTableModRefBS.hpp"
  31 #include "oops/oop.inline.hpp"
  32 #include "runtime/java.hpp"
  33 
  34 // Whereas PSOldGen takes the maximum size of the generation
  35 // (which doesn't change in the case of PSOldGen) as a parameter,
  36 // ASPSOldGen takes the upper limit on the size of
  37 // the generation as a parameter.  In ASPSOldGen the
  38 // maximum size of the generation can change as the boundary
  39 // moves.  The "maximum size of the generation" is still a valid
  40 // concept since the generation can grow and shrink within that
  41 // maximum.  There are lots of useful checks that use that
  42 // maximum.  In PSOldGen the method max_gen_size() returns
  43 // _max_gen_size (as set by the PSOldGen constructor).  This
  44 // is how it always worked.  In ASPSOldGen max_gen_size()
  45 // returned the size of the reserved space for the generation.
  46 // That can change as the boundary moves.  Below the limit of
  47 // the size of the generation is passed to the PSOldGen constructor
  48 // for "_max_gen_size" (have to pass something) but it is not used later.
  49 //
  50 ASPSOldGen::ASPSOldGen(size_t initial_size,
  51                        size_t min_size,
  52                        size_t size_limit,
  53                        const char* gen_name,
  54                        int level) :
  55   PSOldGen(initial_size, min_size, size_limit, gen_name, level),
  56   _gen_size_limit(size_limit)
  57 {}
  58 
  59 ASPSOldGen::ASPSOldGen(PSVirtualSpace* vs,
  60                        size_t initial_size,
  61                        size_t min_size,
  62                        size_t size_limit,
  63                        const char* gen_name,
  64                        int level) :
  65   PSOldGen(initial_size, min_size, size_limit, gen_name, level),
  66   _gen_size_limit(size_limit)
  67 {
  68   _virtual_space = vs;
  69 }
  70 
  71 void ASPSOldGen::initialize_work(const char* perf_data_name, int level) {
  72   PSOldGen::initialize_work(perf_data_name, level);
  73 
  74   // The old gen can grow to gen_size_limit().  _reserve reflects only
  75   // the current maximum that can be committed.
  76   assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check");
  77 
  78   initialize_performance_counters(perf_data_name, level);
  79 }
  80 
  81 void ASPSOldGen::reset_after_change() {
  82   _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(),
  83                         (HeapWord*)virtual_space()->high_boundary());
  84   post_resize();
  85 }
  86 
  87 
  88 size_t ASPSOldGen::available_for_expansion() {
  89   assert(virtual_space()->is_aligned(gen_size_limit()), "not aligned");
  90   assert(gen_size_limit() >= virtual_space()->committed_size(), "bad gen size");
  91 
  92   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
  93   size_t result =  gen_size_limit() - virtual_space()->committed_size();
  94   size_t result_aligned = align_size_down(result, heap->generation_alignment());
  95   return result_aligned;
  96 }
  97 
  98 size_t ASPSOldGen::available_for_contraction() {
  99   size_t uncommitted_bytes = virtual_space()->uncommitted_size();
 100   if (uncommitted_bytes != 0) {
 101     return uncommitted_bytes;
 102   }
 103 
 104   ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
 105   const size_t gen_alignment = heap->generation_alignment();
 106   PSAdaptiveSizePolicy* policy = heap->size_policy();
 107   const size_t working_size =
 108     used_in_bytes() + (size_t) policy->avg_promoted()->padded_average();
 109   const size_t working_aligned = align_size_up(working_size, gen_alignment);
 110   const size_t working_or_min = MAX2(working_aligned, min_gen_size());
 111   if (working_or_min > reserved().byte_size()) {
 112     // If the used or minimum gen size (aligned up) is greater
 113     // than the total reserved size, then the space available
 114     // for contraction should (after proper alignment) be 0
 115     return 0;
 116   }
 117   const size_t max_contraction =
 118     reserved().byte_size() - working_or_min;
 119 
 120   // Use the "increment" fraction instead of the "decrement" fraction
 121   // to allow the other gen to expand more aggressively.  The
 122   // "decrement" fraction is conservative because its intent is to
 123   // only reduce the footprint.
 124 
 125   size_t result = policy->promo_increment_aligned_down(max_contraction);
 126   // Also adjust for inter-generational alignment
 127   size_t result_aligned = align_size_down(result, gen_alignment);
 128 
 129   log_trace(gc, ergo)("ASPSOldGen::available_for_contraction: " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 130                       result_aligned/K, result_aligned);
 131   log_trace(gc, ergo)(" reserved().byte_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 132                       reserved().byte_size()/K, reserved().byte_size());
 133   size_t working_promoted = (size_t) policy->avg_promoted()->padded_average();
 134   log_trace(gc, ergo)(" padded promoted " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 135                       working_promoted/K, working_promoted);
 136   log_trace(gc, ergo)(" used " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 137                       used_in_bytes()/K, used_in_bytes());
 138   log_trace(gc, ergo)(" min_gen_size() " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 139                       min_gen_size()/K, min_gen_size());
 140   log_trace(gc, ergo)(" max_contraction " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 141                       max_contraction/K, max_contraction);
 142   log_trace(gc, ergo)("    without alignment " SIZE_FORMAT " K / " SIZE_FORMAT_HEX,
 143                       policy->promo_increment(max_contraction)/K, policy->promo_increment(max_contraction));
 144   log_trace(gc, ergo)(" alignment " SIZE_FORMAT_HEX, gen_alignment);
 145 
 146   assert(result_aligned <= max_contraction, "arithmetic is wrong");
 147   return result_aligned;
 148 }