1 /*
   2  * Copyright (c) 2001, 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_implementation/g1/g1BiasedArray.hpp"
  27 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 #include "runtime/virtualspace.hpp"
  30 #include "services/memTracker.hpp"
  31 #include "utilities/bitMap.inline.hpp"
  32 
  33 G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,
  34                                              size_t actual_size,
  35                                              size_t commit_granularity,
  36                                              size_t region_granularity,
  37                                              MemoryType type) :
  38   _storage(),
  39   _commit_granularity(commit_granularity),
  40   _region_granularity(region_granularity),
  41   _listener(NULL),
  42   _commit_map() {
  43   guarantee(is_power_of_2(commit_granularity), "must be");
  44   guarantee(is_power_of_2(region_granularity), "must be");
  45   _storage.initialize_with_granularity(rs, actual_size, commit_granularity);
  46 
  47   MemTracker::record_virtual_memory_type((address)rs.base(), type);
  48 }
  49 
  50 // G1RegionToSpaceMapper implementation where the region granularity is larger than
  51 // or the same as the commit granularity.
  52 // Basically, the space corresponding to one region region spans several OS pages.
  53 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  54  private:
  55   size_t _pages_per_region;
  56 
  57  public:
  58   G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,
  59                                       size_t actual_size,
  60                                       size_t os_commit_granularity,
  61                                       size_t alloc_granularity,
  62                                       size_t commit_factor,
  63                                       MemoryType type) :
  64     G1RegionToSpaceMapper(rs, actual_size, os_commit_granularity, alloc_granularity, type),
  65     _pages_per_region(alloc_granularity / (os_commit_granularity * commit_factor)) {
  66 
  67     guarantee(alloc_granularity >= os_commit_granularity, "allocation granularity smaller than commit granularity");
  68     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
  69   }
  70 
  71   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
  72     bool zero_filled = _storage.commit(start_idx * _pages_per_region, num_regions * _pages_per_region);
  73     _commit_map.set_range(start_idx, start_idx + num_regions);
  74     fire_on_commit(start_idx, num_regions, zero_filled);
  75   }
  76 
  77   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
  78     _storage.uncommit(start_idx * _pages_per_region, num_regions * _pages_per_region);
  79     _commit_map.clear_range(start_idx, start_idx + num_regions);
  80   }
  81 };
  82 
  83 // G1RegionToSpaceMapper implementation where the region granularity is smaller
  84 // than the commit granularity.
  85 // Basically, the contents of one OS page span several regions.
  86 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  87  private:
  88   class CommitRefcountArray : public G1BiasedMappedArray<uint> {
  89    protected:
  90      virtual uint default_value() const { return 0; }
  91   };
  92 
  93   size_t _regions_per_page;
  94 
  95   CommitRefcountArray _refcounts;
  96 
  97   uintptr_t region_idx_to_page_idx(uint region) const {
  98     return region / _regions_per_page;
  99   }
 100 
 101  public:
 102   G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
 103                                        size_t actual_size,
 104                                        size_t os_commit_granularity,
 105                                        size_t alloc_granularity,
 106                                        size_t commit_factor,
 107                                        MemoryType type) :
 108     G1RegionToSpaceMapper(rs, actual_size, os_commit_granularity, alloc_granularity, type),
 109     _regions_per_page((os_commit_granularity * commit_factor) / alloc_granularity), _refcounts() {
 110 
 111     guarantee((os_commit_granularity * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
 112     _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_size_up(rs.size(), os_commit_granularity)), os_commit_granularity);
 113     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
 114   }
 115 
 116   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
 117     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
 118       assert(!_commit_map.at(i), err_msg("Trying to commit storage at region "INTPTR_FORMAT" that is already committed", i));
 119       uintptr_t idx = region_idx_to_page_idx(i);
 120       uint old_refcount = _refcounts.get_by_index(idx);
 121       bool zero_filled = false;
 122       if (old_refcount == 0) {
 123         zero_filled = _storage.commit(idx, 1);
 124       }
 125       _refcounts.set_by_index(idx, old_refcount + 1);
 126       _commit_map.set_bit(i);
 127       fire_on_commit(i, 1, zero_filled);
 128     }
 129   }
 130 
 131   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
 132     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
 133       assert(_commit_map.at(i), err_msg("Trying to uncommit storage at region "INTPTR_FORMAT" that is not committed", i));
 134       uintptr_t idx = region_idx_to_page_idx(i);
 135       uint old_refcount = _refcounts.get_by_index(idx);
 136       assert(old_refcount > 0, "must be");
 137       if (old_refcount == 1) {
 138         _storage.uncommit(idx, 1);
 139       }
 140       _refcounts.set_by_index(idx, old_refcount - 1);
 141       _commit_map.clear_bit(i);
 142     }
 143   }
 144 };
 145 
 146 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
 147   if (_listener != NULL) {
 148     _listener->on_commit(start_idx, num_regions, zero_filled);
 149   }
 150 }
 151 
 152 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
 153                                                             size_t actual_size,
 154                                                             size_t os_commit_granularity,
 155                                                             size_t region_granularity,
 156                                                             size_t commit_factor,
 157                                                             MemoryType type) {
 158 
 159   if (region_granularity >= (os_commit_granularity * commit_factor)) {
 160     return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, os_commit_granularity, region_granularity, commit_factor, type);
 161   } else {
 162     return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, os_commit_granularity, region_granularity, commit_factor, type);
 163   }
 164 }