lfu_rp.cc revision 12727 
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 <cassert>
34#include <memory>
35
36#include "params/LFURP.hh"
37
38LFURP::LFURP(const Params *p)
39    : BaseReplacementPolicy(p)
40{
41}
42
43void
44LFURP::invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
45const
46{
47    // Reset reference count
48    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount = 0;
49}
50
51void
52LFURP::touch(const std::shared_ptr<ReplacementData>& replacement_data) const
53{
54    // Update reference count
55    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount++;
56}
57
58void
59LFURP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
60{
61    // Reset reference count
62    std::static_pointer_cast<LFUReplData>(replacement_data)->refCount = 1;
63}
64
65ReplaceableEntry*
66LFURP::getVictim(const ReplacementCandidates& candidates) const
67{
68    // There must be at least one replacement candidate
69    assert(candidates.size() > 0);
70
71    // Visit all candidates to find victim
72    ReplaceableEntry* victim = candidates[0];
73    for (const auto& candidate : candidates) {
74        // Update victim entry if necessary
75        if (std::static_pointer_cast<LFUReplData>(
76                    candidate->replacementData)->refCount <
77                std::static_pointer_cast<LFUReplData>(
78                    victim->replacementData)->refCount) {
79            victim = candidate;
80        }
81    }
82
83    return victim;
84}
85
86std::shared_ptr<ReplacementData>
87LFURP::instantiateEntry()
88{
89    return std::shared_ptr<ReplacementData>(new LFUReplData());
90}
91
92LFURP*
93LFURPParams::create()
94{
95    return new LFURP(this);
96}
97