1/*
2 * Copyright (c) 2001, 2017, 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/g1/g1BiasedArray.hpp"
27#include "gc/g1/g1RegionToSpaceMapper.hpp"
28#include "memory/allocation.inline.hpp"
29#include "memory/virtualspace.hpp"
30#include "services/memTracker.hpp"
31#include "utilities/align.hpp"
32#include "utilities/bitMap.inline.hpp"
33
34G1RegionToSpaceMapper::G1RegionToSpaceMapper(ReservedSpace rs,
35                                             size_t used_size,
36                                             size_t page_size,
37                                             size_t region_granularity,
38                                             size_t commit_factor,
39                                             MemoryType type) :
40  _storage(rs, used_size, page_size),
41  _region_granularity(region_granularity),
42  _listener(NULL),
43  _commit_map(rs.size() * commit_factor / region_granularity, mtGC) {
44  guarantee(is_power_of_2(page_size), "must be");
45  guarantee(is_power_of_2(region_granularity), "must be");
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.
53class 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 page_size,
61                                      size_t alloc_granularity,
62                                      size_t commit_factor,
63                                      MemoryType type) :
64    G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
65    _pages_per_region(alloc_granularity / (page_size * commit_factor)) {
66
67    guarantee(alloc_granularity >= page_size, "allocation granularity smaller than commit granularity");
68  }
69
70  virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
71    size_t const start_page = (size_t)start_idx * _pages_per_region;
72    bool zero_filled = _storage.commit(start_page, num_regions * _pages_per_region);
73    if (AlwaysPreTouch) {
74      _storage.pretouch(start_page, num_regions * _pages_per_region, pretouch_gang);
75    }
76    _commit_map.set_range(start_idx, start_idx + num_regions);
77    fire_on_commit(start_idx, num_regions, zero_filled);
78  }
79
80  virtual void uncommit_regions(uint start_idx, size_t num_regions) {
81    _storage.uncommit((size_t)start_idx * _pages_per_region, num_regions * _pages_per_region);
82    _commit_map.clear_range(start_idx, start_idx + num_regions);
83  }
84};
85
86// G1RegionToSpaceMapper implementation where the region granularity is smaller
87// than the commit granularity.
88// Basically, the contents of one OS page span several regions.
89class G1RegionsSmallerThanCommitSizeMapper : public G1RegionToSpaceMapper {
90 private:
91  class CommitRefcountArray : public G1BiasedMappedArray<uint> {
92   protected:
93     virtual uint default_value() const { return 0; }
94  };
95
96  size_t _regions_per_page;
97
98  CommitRefcountArray _refcounts;
99
100  uintptr_t region_idx_to_page_idx(uint region) const {
101    return region / _regions_per_page;
102  }
103
104 public:
105  G1RegionsSmallerThanCommitSizeMapper(ReservedSpace rs,
106                                       size_t actual_size,
107                                       size_t page_size,
108                                       size_t alloc_granularity,
109                                       size_t commit_factor,
110                                       MemoryType type) :
111    G1RegionToSpaceMapper(rs, actual_size, page_size, alloc_granularity, commit_factor, type),
112    _regions_per_page((page_size * commit_factor) / alloc_granularity), _refcounts() {
113
114    guarantee((page_size * commit_factor) >= alloc_granularity, "allocation granularity smaller than commit granularity");
115    _refcounts.initialize((HeapWord*)rs.base(), (HeapWord*)(rs.base() + align_up(rs.size(), page_size)), page_size);
116  }
117
118  virtual void commit_regions(uint start_idx, size_t num_regions, WorkGang* pretouch_gang) {
119    size_t const NoPage = ~(size_t)0;
120
121    size_t first_committed = NoPage;
122    size_t num_committed = 0;
123
124    bool all_zero_filled = true;
125
126    for (uint i = start_idx; i < start_idx + num_regions; i++) {
127      assert(!_commit_map.at(i), "Trying to commit storage at region %u that is already committed", i);
128      size_t idx = region_idx_to_page_idx(i);
129      uint old_refcount = _refcounts.get_by_index(idx);
130
131      bool zero_filled = false;
132      if (old_refcount == 0) {
133        if (first_committed == NoPage) {
134          first_committed = idx;
135          num_committed = 1;
136        } else {
137          num_committed++;
138        }
139        zero_filled = _storage.commit(idx, 1);
140      }
141      all_zero_filled &= zero_filled;
142
143      _refcounts.set_by_index(idx, old_refcount + 1);
144      _commit_map.set_bit(i);
145    }
146    if (AlwaysPreTouch && num_committed > 0) {
147      _storage.pretouch(first_committed, num_committed, pretouch_gang);
148    }
149    fire_on_commit(start_idx, num_regions, all_zero_filled);
150  }
151
152  virtual void uncommit_regions(uint start_idx, size_t num_regions) {
153    for (uint i = start_idx; i < start_idx + num_regions; i++) {
154      assert(_commit_map.at(i), "Trying to uncommit storage at region %u that is not committed", i);
155      size_t idx = region_idx_to_page_idx(i);
156      uint old_refcount = _refcounts.get_by_index(idx);
157      assert(old_refcount > 0, "must be");
158      if (old_refcount == 1) {
159        _storage.uncommit(idx, 1);
160      }
161      _refcounts.set_by_index(idx, old_refcount - 1);
162      _commit_map.clear_bit(i);
163    }
164  }
165};
166
167void G1RegionToSpaceMapper::fire_on_commit(uint start_idx, size_t num_regions, bool zero_filled) {
168  if (_listener != NULL) {
169    _listener->on_commit(start_idx, num_regions, zero_filled);
170  }
171}
172
173G1RegionToSpaceMapper* G1RegionToSpaceMapper::create_mapper(ReservedSpace rs,
174                                                            size_t actual_size,
175                                                            size_t page_size,
176                                                            size_t region_granularity,
177                                                            size_t commit_factor,
178                                                            MemoryType type) {
179
180  if (region_granularity >= (page_size * commit_factor)) {
181    return new G1RegionsLargerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
182  } else {
183    return new G1RegionsSmallerThanCommitSizeMapper(rs, actual_size, page_size, region_granularity, commit_factor, type);
184  }
185}
186