mru_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/mru_rp.hh"
32
33#include <memory>
34
35MRURP::MRURP(const Params *p)
36    : BaseReplacementPolicy(p)
37{
38}
39
40void
41MRURP::invalidate(const std::shared_ptr<ReplacementData>& replacement_data)
42const
43{
44    // Reset last touch timestamp
45    std::static_pointer_cast<MRUReplData>(
46        replacement_data)->lastTouchTick = Tick(0);
47}
48
49void
50MRURP::touch(const std::shared_ptr<ReplacementData>& replacement_data) const
51{
52    // Update last touch timestamp
53    std::static_pointer_cast<MRUReplData>(
54        replacement_data)->lastTouchTick = curTick();
55}
56
57void
58MRURP::reset(const std::shared_ptr<ReplacementData>& replacement_data) const
59{
60    // Set last touch timestamp
61    std::static_pointer_cast<MRUReplData>(
62        replacement_data)->lastTouchTick = curTick();
63}
64
65ReplaceableEntry*
66MRURP::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<MRUReplData>(
76                    candidate->replacementData)->lastTouchTick >
77                std::static_pointer_cast<MRUReplData>(
78                    victim->replacementData)->lastTouchTick) {
79            victim = candidate;
80        }
81    }
82
83    return victim;
84}
85
86std::shared_ptr<ReplacementData>
87MRURP::instantiateEntry()
88{
89    return std::shared_ptr<ReplacementData>(new MRUReplData());
90}
91
92MRURP*
93MRURPParams::create()
94{
95    return new MRURP(this);
96}
97