base.hh revision 12684
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#ifndef __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 32#define __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 33 34#include <memory> 35 36#include "params/BaseReplacementPolicy.hh" 37#include "sim/sim_object.hh" 38 39/** 40 * The replacement data needed by the replacement policy. 41 * Each replacement policy should have its own replacement data. 42 */ 43struct ReplacementData {}; 44 45/** 46 * A replaceable entry is used by any table-like structure that needs to 47 * implement replacement functionality. It provides the replacement data 48 * pointer instantiated and needed by the replacement policy used. 49 * @sa Replacement Policies 50 */ 51class ReplaceableEntry 52{ 53 public: 54 /** 55 * Replacement data associated to this entry. 56 * It is instantiated by the replacement policy. 57 */ 58 std::shared_ptr<ReplacementData> replacementData; 59}; 60 61/** 62 * Replacement candidates as chosen by the indexing policy. 63 */ 64typedef std::vector<ReplaceableEntry*> ReplacementCandidates; 65 66/** 67 * A common base class of cache replacement policy objects. 68 */ 69class BaseReplacementPolicy : public SimObject 70{ 71 public: 72 /** 73 * Convenience typedef. 74 */ 75 typedef BaseReplacementPolicyParams Params; 76 77 /** 78 * Construct and initiliaze this replacement policy. 79 */ 80 BaseReplacementPolicy(const Params *p) : SimObject(p) {} 81 82 /** 83 * Destructor. 84 */ 85 virtual ~BaseReplacementPolicy() {} 86 87 /** 88 * Invalidate replacement data to set it as the next probable victim. 89 * 90 * @param replacement_data Replacement data to be invalidated. 91 */ 92 virtual void invalidate(const std::shared_ptr<ReplacementData>& 93 replacement_data) const = 0; 94 95 /** 96 * Update replacement data. 97 * 98 * @param replacement_data Replacement data to be touched. 99 */ 100 virtual void touch(const std::shared_ptr<ReplacementData>& 101 replacement_data) const = 0; 102 103 /** 104 * Reset replacement data. Used when it's holder is inserted/validated. 105 * 106 * @param replacement_data Replacement data to be reset. 107 */ 108 virtual void reset(const std::shared_ptr<ReplacementData>& 109 replacement_data) const = 0; 110 111 /** 112 * Find replacement victim among candidates. 113 * 114 * @param candidates Replacement candidates, selected by indexing policy. 115 * @return Replacement entry to be replaced. 116 */ 117 virtual ReplaceableEntry* getVictim( 118 const ReplacementCandidates& candidates) const = 0; 119 120 /** 121 * Instantiate a replacement data entry. 122 * 123 * @return A shared pointer to the new replacement data. 124 */ 125 virtual std::shared_ptr<ReplacementData> instantiateEntry() = 0; 126}; 127 128#endif // __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 129