lfu_rp.cc revision 12684:44ebd2bc020f 
1/**
2 * Copyright (c) 2018 Inria
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Daniel Carvalho
29 */
30
31#include "mem/cache/replacement_policies/lfu_rp.hh"
32
33#include <memory>
34
35LFURP::LFURP(const Params *p)
36    : BaseReplacementPolicy(p)
37{
38}
39
40void
41LFURP::invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
42const
43{
44    // Reset reference count
45    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount = 0;
46}
47
48void
49LFURP::touch(const std::shared_ptr<ReplacementData>& replacement_data) const
50{
51    // Update reference count
52    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount++;
53}
54
55void
56LFURP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
57{
58    // Reset reference count
59    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount = 1;
60}
61
62ReplaceableEntry*
63LFURP::getVictim(const ReplacementCandidates& candidates) const
64{
65    // There must be at least one replacement candidate
66    assert(candidates.size() > 0);
67
68    // Visit all candidates to find victim
69    ReplaceableEntry* victim = candidates[0];
70    for (const auto& candidate : candidates) {
71        // Update victim entry if necessary
72        if (std::static_pointer_cast<LFUReplData>(
73                    candidate->replacementData)->refCount <
74                std::static_pointer_cast<LFUReplData>(
75                    victim->replacementData)->refCount) {
76            victim = candidate;
77        }
78    }
79
80    return victim;
81}
82
83std::shared_ptr<ReplacementData>
84LFURP::instantiateEntry()
85{
86    return std::shared_ptr<ReplacementData>(new LFUReplData());
87}
88
89LFURP*
90LFURPParams::create()
91{
92    return new LFURP(this);
93}
94