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