src/base/fast_alloc.cc

   1 /*
   2  * Copyright (c) 2000-2005 The Regents of The University of Michigan
   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: Steve Reinhardt
  29  */
  30
  31 /*
  32  * This code was originally written by Steve Reinhardt as part of
  33  * the Wisconsin Wind Tunnel simulator.  Relicensed as part of M5
  34  * by permission.
  35  */
  36
  37 #include <assert.h>
  38 #include "base/fast_alloc.hh"
  39
  40 #if !NO_FAST_ALLOC
  41
  42 #ifdef __GNUC__
  43 #pragma implementation
  44 #endif
  45
  46 void *FastAlloc::freeLists[Num_Buckets];
  47
  48 #ifdef FAST_ALLOC_STATS
  49 unsigned FastAlloc::newCount[Num_Buckets];
  50 unsigned FastAlloc::deleteCount[Num_Buckets];
  51 unsigned FastAlloc::allocCount[Num_Buckets];
  52 #endif
  53
  54 void *FastAlloc::moreStructs(int bucket)
  55 {
  56     assert(bucket > 0 && bucket < Num_Buckets);
  57
  58     int sz = bucket * Alloc_Quantum;
  59     const int nstructs = Num_Structs_Per_New;   // how many to allocate?
  60     char *p = ::new char[nstructs * sz];
  61
  62 #ifdef FAST_ALLOC_STATS
  63     ++allocCount[bucket];
  64 #endif
  65
  66     freeLists[bucket] = p;
  67     for (int i = 0; i < (nstructs-2); ++i, p += sz)
  68         *(void **)p = p + sz;
  69     *(void **)p = 0;
  70
  71     return (p + sz);
  72 }
  73
  74
  75 #ifdef FAST_ALLOC_DEBUG
  76
  77 #include <typeinfo>
  78 #include <iostream>
  79 #include <iomanip>
  80 #include <map>
  81 #include <string>
  82
  83 using namespace std;
  84
  85 // count of in-use FastAlloc objects
  86 int FastAlloc::numInUse;
  87
  88 // dummy head & tail object for doubly linked list of in-use FastAlloc
  89 // objects
  90 FastAlloc FastAlloc::inUseHead(&FastAlloc::inUseHead, &FastAlloc::inUseHead);
  91
  92 // special constructor for dummy head: make inUsePrev & inUseNext
  93 // point to self
  94 FastAlloc::FastAlloc(FastAlloc *prev, FastAlloc *next)
  95 {
  96     inUsePrev = prev;
  97     inUseNext = next;
  98 }
  99
 100
 101 // constructor: marks as in use, add to in-use list
 102 FastAlloc::FastAlloc()
 103 {
 104     // mark this object in use
 105     inUse = true;
 106
 107     // update count
 108     ++numInUse;
 109
 110     // add to tail of list of in-use objects ("before" dummy head)
 111     FastAlloc *myNext = &inUseHead;
 112     FastAlloc *myPrev = inUseHead.inUsePrev;
 113
 114     inUsePrev = myPrev;
 115     inUseNext = myNext;
 116     myPrev->inUseNext = this;
 117     myNext->inUsePrev = this;
 118 }
 119
 120 // destructor: mark not in use, remove from in-use list
 121 FastAlloc::~FastAlloc()
 122 {
 123     assert(inUse);
 124     inUse = false;
 125
 126     --numInUse;
 127     assert(numInUse >= 0);
 128
 129     // remove me from in-use list
 130     inUsePrev->inUseNext = inUseNext;
 131     inUseNext->inUsePrev = inUsePrev;
 132 }
 133
 134
 135 // summarize in-use list
 136 void
 137 FastAlloc::dump_summary()
 138 {
 139     map<string, int> typemap;
 140
 141     for (FastAlloc *p = inUseHead.inUseNext; p != &inUseHead; p = p->inUseNext)
 142     {
 143         ++typemap[typeid(*p).name()];
 144     }
 145
 146     map<string, int>::const_iterator mapiter;
 147
 148     cout << " count  type\n"
 149          << " -----  ----\n";
 150     for (mapiter = typemap.begin(); mapiter != typemap.end(); ++mapiter)
 151     {
 152         cout << setw(6) << mapiter->second << "  " << mapiter->first << endl;
 153     }
 154 }
 155
 156
 157 // show oldest n items on in-use list
 158 void
 159 FastAlloc::dump_oldest(int n)
 160 {
 161     // sanity check: don't want to crash the debugger if you forget to
 162     // pass in a parameter
 163     if (n < 0 || n > numInUse)
 164     {
 165         cout << "FastAlloc::dump_oldest: bad arg " << n
 166              << " (" << numInUse << " objects in use" << endl;
 167         return;
 168     }
 169
 170     for (FastAlloc *p = inUseHead.inUsePrev;
 171          p != &inUseHead && n > 0;
 172          p = p->inUsePrev, --n)
 173     {
 174         cout << p << " " << typeid(*p).name() << endl;
 175     }
 176 }
 177
 178
 179 //
 180 // C interfaces to FastAlloc::dump_summary() and FastAlloc::dump_oldest().
 181 // gdb seems to have trouble with calling C++ functions directly.
 182 //
 183 fast_alloc_summary()
 184 {
 185     FastAlloc::dump_summary();
 186 }
 187
 188 fast_alloc_oldest(int n)
 189 {
 190     FastAlloc::dump_oldest(n);
 191 }
 192
 193 #endif
 194
 195 #endif // NO_FAST_ALLOC