base.hh revision 12600
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 "mem/cache/base.hh" 35#include "mem/cache/blk.hh" 36#include "params/BaseReplacementPolicy.hh" 37#include "sim/sim_object.hh" 38 39/** 40 * Replacement candidates as chosen by the indexing policy. 41 * 42 * The base functions touch() and reset() must be called by all subclasses 43 * that override them. 44 * 45 * @todo 46 * Currently the replacement candidates are simply the cache blocks 47 * derived from the possible placement locations of an address, as 48 * defined by the getPossibleLocations() from BaseTags. In a future 49 * patch it should be an inheritable class to allow the replacement 50 * policies to be used with any table-like structure that needs to 51 * replace its entries. 52 */ 53typedef std::vector<CacheBlk*> ReplacementCandidates; 54 55/** 56 * A common base class of cache replacement policy objects. 57 */ 58class BaseReplacementPolicy : public SimObject 59{ 60 public: 61 /** 62 * Convenience typedef. 63 */ 64 typedef BaseReplacementPolicyParams Params; 65 66 /** 67 * Construct and initiliaze this replacement policy. 68 */ 69 BaseReplacementPolicy(const Params *p); 70 71 /** 72 * Destructor. 73 */ 74 virtual ~BaseReplacementPolicy() {} 75 76 /** 77 * Touch a block to update its replacement data. 78 * Updates number of references. 79 * 80 * This base function must be called by all subclasses that override it. 81 * 82 * @param blk Cache block to be touched. 83 */ 84 virtual void touch(CacheBlk *blk); 85 86 /** 87 * Reset replacement data for a block. Used when a block is inserted. 88 * Sets the insertion tick, and update number of references. 89 * 90 * This base function must be called by all subclasses that override it. 91 * 92 * @param blk Cache block to be reset. 93 */ 94 virtual void reset(CacheBlk *blk); 95 96 /** 97 * Find replacement victim among candidates. 98 * 99 * @param candidates Replacement candidates, selected by indexing policy. 100 * @return Cache block to be replaced. 101 */ 102 virtual CacheBlk* getVictim(const ReplacementCandidates& candidates) = 0; 103}; 104 105#endif // __MEM_CACHE_REPLACEMENT_POLICIES_BASE_HH__ 106