base/fast_alloc.cc

   1 /*
   2  * Copyright (c) 2003 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 #ifdef __GNUC__
  36 #pragma implementation
  37 #endif
  38
  39 #include <assert.h>
  40 #include "base/fast_alloc.hh"
  41
  42 void *FastAlloc::freeLists[Num_Buckets];
  43
  44 #ifdef FAST_ALLOC_STATS
  45 unsigned FastAlloc::newCount[Num_Buckets];
  46 unsigned FastAlloc::deleteCount[Num_Buckets];
  47 unsigned FastAlloc::allocCount[Num_Buckets];
  48 #endif
  49
  50 void *FastAlloc::moreStructs(int bucket)
  51 {
  52     assert(bucket > 0 && bucket < Num_Buckets);
  53
  54     int sz = bucket * Alloc_Quantum;
  55     const int nstructs = Num_Structs_Per_New;   // how many to allocate?
  56     char *p = ::new char[nstructs * sz];
  57
  58 #ifdef FAST_ALLOC_STATS
  59     ++allocCount[bucket];
  60 #endif
  61
  62     freeLists[bucket] = p;
  63     for (int i = 0; i < (nstructs-2); ++i, p += sz)
  64         *(void **)p = p + sz;
  65     *(void **)p = 0;
  66
  67     return (p + sz);
  68 }
  69
  70
  71 #ifdef FAST_ALLOC_DEBUG
  72
  73 #include <typeinfo>
  74 #include <iostream>
  75 #include <iomanip>
  76 #include <map>
  77 #include <string>
  78
  79 using namespace std;
  80
  81 // count of in-use FastAlloc objects
  82 int FastAlloc::numInUse;
  83
  84 // dummy head & tail object for doubly linked list of in-use FastAlloc
  85 // objects
  86 FastAlloc FastAlloc::inUseHead(&FastAlloc::inUseHead, &FastAlloc::inUseHead);
  87
  88 // special constructor for dummy head: make inUsePrev & inUseNext
  89 // point to self
  90 FastAlloc::FastAlloc(FastAlloc *prev, FastAlloc *next)
  91 {
  92     inUsePrev = prev;
  93     inUseNext = next;
  94 }
  95
  96
  97 // constructor: marks as in use, add to in-use list
  98 FastAlloc::FastAlloc()
  99 {
 100     // mark this object in use
 101     inUse = true;
 102
 103     // update count
 104     ++numInUse;
 105
 106     // add to tail of list of in-use objects ("before" dummy head)
 107     FastAlloc *myNext = &inUseHead;
 108     FastAlloc *myPrev = inUseHead.inUsePrev;
 109
 110     inUsePrev = myPrev;
 111     inUseNext = myNext;
 112     myPrev->inUseNext = this;
 113     myNext->inUsePrev = this;
 114 }
 115
 116 // destructor: mark not in use, remove from in-use list
 117 FastAlloc::~FastAlloc()
 118 {
 119     assert(inUse);
 120     inUse = false;
 121
 122     --numInUse;
 123     assert(numInUse >= 0);
 124
 125     // remove me from in-use list
 126     inUsePrev->inUseNext = inUseNext;
 127     inUseNext->inUsePrev = inUsePrev;
 128 }
 129
 130
 131 // summarize in-use list
 132 void
 133 FastAlloc::dump_summary()
 134 {
 135     map<string, int> typemap;
 136
 137     for (FastAlloc *p = inUseHead.inUseNext; p != &inUseHead; p = p->inUseNext)
 138     {
 139         ++typemap[typeid(*p).name()];
 140     }
 141
 142     map<string, int>::const_iterator mapiter;
 143
 144     cout << " count  type\n"
 145          << " -----  ----\n";
 146     for (mapiter = typemap.begin(); mapiter != typemap.end(); ++mapiter)
 147     {
 148         cout << setw(6) << mapiter->second << "  " << mapiter->first << endl;
 149     }
 150 }
 151
 152
 153 // show oldest n items on in-use list
 154 void
 155 FastAlloc::dump_oldest(int n)
 156 {
 157     // sanity check: don't want to crash the debugger if you forget to
 158     // pass in a parameter
 159     if (n < 0 || n > numInUse)
 160     {
 161         cout << "FastAlloc::dump_oldest: bad arg " << n
 162              << " (" << numInUse << " objects in use" << endl;
 163         return;
 164     }
 165
 166     for (FastAlloc *p = inUseHead.inUsePrev;
 167          p != &inUseHead && n > 0;
 168          p = p->inUsePrev, --n)
 169     {
 170         cout << p << " " << typeid(*p).name() << endl;
 171     }
 172 }
 173
 174
 175 //
 176 // C interfaces to FastAlloc::dump_summary() and FastAlloc::dump_oldest().
 177 // gdb seems to have trouble with calling C++ functions directly.
 178 //
 179 extern "C" void
 180 fast_alloc_summary()
 181 {
 182     FastAlloc::dump_summary();
 183 }
 184
 185 extern "C" void
 186 fast_alloc_oldest(int n)
 187 {
 188     FastAlloc::dump_oldest(n);
 189 }
 190
 191 #endif