rev 6992 : 8062063: Usage of UseHugeTLBFS, UseLargePagesInMetaspace and huge SurvivorAlignmentInBytes cause crashes in CMBitMapClosure::do_bit
Summary: Making sure committed memory is cleared when re-committed, even if using large pages.
Reviewed-by: kbarrett, tschatzl

   1 /*
   2  * Copyright (c) 2001, 2013, 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 commit_granularity,
  35                                              size_t region_granularity,
  36                                              MemoryType type) :
  37   _storage(),
  38   _commit_granularity(commit_granularity),
  39   _region_granularity(region_granularity),
  40   _listener(NULL),
  41   _commit_map() {
  42   guarantee(is_power_of_2(commit_granularity), "must be");
  43   guarantee(is_power_of_2(region_granularity), "must be");
  44   _storage.initialize_with_granularity(rs, commit_granularity);
  45 
  46   MemTracker::record_virtual_memory_type((address)rs.base(), type);
  47 }
  48 
  49 // G1RegionToSpaceMapper implementation where the region granularity is larger than
  50 // or the same as the commit granularity.
  51 // Basically, the space corresponding to one region region spans several OS pages.
  52 class G1RegionsLargerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  53  private:
  54   size_t _pages_per_region;
  55 
  56  public:
  57   G1RegionsLargerThanCommitSizeMapper(ReservedSpace rs,
  58                                       size_t os_commit_granularity,
  59                                       size_t alloc_granularity,
  60                                       size_t commit_factor,
  61                                       MemoryType type) :
  62      G1RegionToSpaceMapper(rs, os_commit_granularity, alloc_granularity, type),
  63     _pages_per_region(alloc_granularity / (os_commit_granularity * commit_factor)) {
  64 
  65     guarantee(alloc_granularity >= os_commit_granularity, "allocation granularity smaller than commit granularity");
  66     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
  67   }
  68 
  69   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
  70     bool zero_filled = _storage.commit(start_idx * _pages_per_region, num_regions * _pages_per_region);
  71     _commit_map.set_range(start_idx, start_idx + num_regions);
  72     fire_on_commit(start_idx, num_regions, zero_filled);
  73   }
  74 
  75   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
  76     _storage.uncommit(start_idx * _pages_per_region, num_regions * _pages_per_region);
  77     _commit_map.clear_range(start_idx, start_idx + num_regions);
  78   }
  79 };
  80 
  81 // G1RegionToSpaceMapper implementation where the region granularity is smaller
  82 // than the commit granularity.
  83 // Basically, the contents of one OS page span several regions.
  84 class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
  85  private:
  86   class CommitRefcountArray : public G1BiasedMappedArray<uint> {
  87    protected:
  88      virtual uint default_value() const { return 0; }
  89   };
  90 
  91   size_t _regions_per_page;
  92 
  93   CommitRefcountArray _refcounts;
  94 
  95   uintptr_t region_idx_to_page_idx(uint region) const {
  96     return region / _regions_per_page;
  97   }
  98 
  99  public:
 100   G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
 101                                        size_t os_commit_granularity,
 102                                        size_t alloc_granularity,
 103                                        size_t commit_factor,
 104                                        MemoryType type) :
 105      G1RegionToSpaceMapper(rs, os_commit_granularity, alloc_granularity, type),
 106     _regions_per_page((os_commit_granularity * commit_factor) / alloc_granularity), _refcounts() {
 107 
 108     guarantee((os_commit_granularity * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
 109     _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + rs.size()), os_commit_granularity);
 110     _commit_map.resize(rs.size() * commit_factor / alloc_granularity, /* in_resource_area */ false);
 111   }
 112 
 113   virtual void commit_regions(uintptr_t start_idx, size_t num_regions) {
 114     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
 115       assert(!_commit_map.at(i), err_msg("Trying to commit storage at region "INTPTR_FORMAT" that is already committed", i));
 116       uintptr_t idx = region_idx_to_page_idx(i);
 117       uint old_refcount = _refcounts.get_by_index(idx);
 118       bool zero_filled = false;
 119       if (old_refcount == 0) {
 120         zero_filled = _storage.commit(idx, 1);

 121       }
 122       _refcounts.set_by_index(idx, old_refcount + 1);
 123       _commit_map.set_bit(i);
 124       fire_on_commit(i, 1, zero_filled);
 125     }
 126   }
 127 
 128   virtual void uncommit_regions(uintptr_t start_idx, size_t num_regions) {
 129     for (uintptr_t i = start_idx; i < start_idx + num_regions; i++) {
 130       assert(_commit_map.at(i), err_msg("Trying to uncommit storage at region "INTPTR_FORMAT" that is not committed", i));
 131       uintptr_t idx = region_idx_to_page_idx(i);
 132       uint old_refcount = _refcounts.get_by_index(idx);
 133       assert(old_refcount > 0, "must be");
 134       if (old_refcount == 1) {
 135         _storage.uncommit(idx, 1);
 136       }
 137       _refcounts.set_by_index(idx, old_refcount - 1);
 138       _commit_map.clear_bit(i);
 139     }
 140   }
 141 };
 142 
 143 void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
 144   if (_listener != NULL) {
 145     _listener->on_commit(start_idx, num_regions, zero_filled);
 146   }
 147 }
 148 
 149 G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
 150                                                             size_t os_commit_granularity,
 151                                                             size_t region_granularity,
 152                                                             size_t commit_factor,
 153                                                             MemoryType type) {
 154 
 155   if (region_granularity >= (os_commit_granularity * commit_factor)) {
 156     return new G1RegionsLargerThanCommitSizeMapper(rs, os_commit_granularity, region_granularity, commit_factor, type);
 157   } else {
 158     return new G1RegionsSmallerThanCommitSizeMapper(rs, os_commit_granularity, region_granularity, commit_factor, type);
 159   }
 160 }
--- EOF ---