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/lru_rp.hh"
32
33#include <cassert>
34#include <memory>
35
36#include "params/LRURP.hh"
37
38LRURP::LRURP(const Params *p)
39    : BaseReplacementPolicy(p)
40{
41}
42
43void
44LRURP::invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
45const
46{
47    // Reset last touch timestamp
48    std::static_pointer_cast<LRUReplData>(
49        replacement_data)->lastTouchTick = Tick(0);
50}
51
52void
53LRURP::touch(const std::shared_ptr<ReplacementData>& replacement_data) const
54{
55    // Update last touch timestamp
56    std::static_pointer_cast<LRUReplData>(
57        replacement_data)->lastTouchTick = curTick();
58}
59
60void
61LRURP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
62{
63    // Set last touch timestamp
64    std::static_pointer_cast<LRUReplData>(
65        replacement_data)->lastTouchTick = curTick();
66}
67
68ReplaceableEntry*
69LRURP::getVictim(const ReplacementCandidates& candidates) const
70{
71    // There must be at least one replacement candidate
72    assert(candidates.size() > 0);
73
74    // Visit all candidates to find victim
75    ReplaceableEntry* victim = candidates[0];
76    for (const auto& candidate : candidates) {
77        // Update victim entry if necessary
78        if (std::static_pointer_cast<LRUReplData>(
79                    candidate->replacementData)->lastTouchTick <
80                std::static_pointer_cast<LRUReplData>(
81                    victim->replacementData)->lastTouchTick) {
82            victim = candidate;
83        }
84    }
85
86    return victim;
87}
88
89std::shared_ptr<ReplacementData>
90LRURP::instantiateEntry()
91{
92    return std::shared_ptr<ReplacementData>(new LRUReplData());
93}
94
95LRURP*
96LRURPParams::create()
97{
98    return new LRURP(this);
99}
100