memcheck/tests/sbfragment.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include "../../config.h"
   4 #if defined(HAVE_MALLINFO)
   5 #include <malloc.h>
   6 #endif
   7
   8 #define BIGINCREASE 32000
   9 int debug = 0;
  10
  11 void stats(char *msg)
  12 {
  13 #if defined(HAVE_MALLINFO)
  14   struct mallinfo mallinfo_result;
  15   mallinfo_result = mallinfo();
  16 #endif
  17
  18   /* from /usr/include/malloc.h */
  19   printf("%s\n", msg);
  20
  21 #if defined(HAVE_MALLINFO)
  22   printf("%10d int arena;    /* non-mmapped space allocated from system */\n", mallinfo_result.arena);
  23   printf("%10d int ordblks;  /* number of free chunks */\n", mallinfo_result.ordblks);
  24   printf("%10d int smblks;   /* number of fastbin blocks */\n", mallinfo_result.smblks);
  25   printf("%10d int hblks;    /* number of mmapped regions */\n", mallinfo_result.hblks);
  26   printf("%10d int hblkhd;   /* space in mmapped regions */\n", mallinfo_result.hblkhd);
  27   printf("%10d int usmblks;  /* maximum total allocated space */\n", mallinfo_result.usmblks);
  28   printf("%10d int fsmblks;  /* space available in freed fastbin blocks */\n", mallinfo_result.fsmblks);
  29   printf("%10d int uordblks; /* total allocated space */\n", mallinfo_result.uordblks);
  30   printf("%10d int fordblks; /* total free space */\n", mallinfo_result.fordblks);
  31   printf("%10d int keepcost; /* top-most, releasable (via malloc_trim) space */\n", mallinfo_result.keepcost);
  32   printf("\n");
  33 #endif
  34 }
  35
  36 int main(int argc, char *argv[])
  37 {
  38
  39   char *big = NULL;
  40
  41   char *newbig;
  42   int malloc_failure = 0;
  43   unsigned long bigsize = 8; // current size of the (reallocated) big block.
  44   int i;
  45   int loop;
  46
  47   // two optional arguments: [nr of loop] [debug]
  48   if (argc > 1)
  49      loop = atoi(argv[1]);
  50   else
  51      loop = 3000;
  52
  53   if (argc > 2)
  54      debug = 1;
  55
  56   bigsize += BIGINCREASE;
  57   big = malloc (bigsize);
  58   if (big == NULL)
  59      printf ("failure %d could not allocate size %lu\n",
  60              ++malloc_failure, bigsize);
  61   if (debug)
  62      printf("big 0x%p\n", big);
  63
  64   for (i = 0; i < loop; i++)
  65     {
  66       bigsize += BIGINCREASE;
  67       newbig = malloc(bigsize);
  68       if (newbig == NULL)
  69          printf ("failure %d could not allocate size %lu\n",
  70                  ++malloc_failure, bigsize);
  71       free (big);
  72       big = newbig;
  73       if (debug)
  74          printf("big 0x%p\n", big);
  75     }
  76
  77   printf ("after %d loops, last size block requested %lu\n", loop, bigsize);
  78   // verify if superblock fragmentation occurred
  79   // We consider that an arena of up to 3 times more than bigsize is ok.
  80   {
  81 #if defined(HAVE_MALLINFO)
  82      struct mallinfo mallinfo_result;
  83      mallinfo_result = mallinfo();
  84      // Under valgrind, hblkhd is 0 : all the space is in arena.
  85      // Under native linux, some space is counted hblkhd.
  86      if (malloc_failure > 0)
  87         printf ("%d mallocs failed, below output is doubful\n", malloc_failure);
  88      if (mallinfo_result.arena + mallinfo_result.hblkhd > 3 * bigsize)
  89         printf("unexpected heap fragmentation %lu\n",
  90                (unsigned long) mallinfo_result.arena
  91                + (unsigned long) mallinfo_result.hblkhd);
  92      else
  93 #endif
  94         printf("reasonable heap usage\n");
  95   }
  96
  97   if (debug)
  98      stats ("before freeing last block");
  99   free (big);
 100   if (debug)
 101      stats ("after freeing last block");
 102
 103   return 0;
 104 }