src/vm-limit.c

   1 /* Functions for memory limit warnings.
   2    Copyright (C) 1990 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 1, or (at your option)
   9 any later version.
  10
  11 GNU Emacs is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include "config.h"
  21 #include "lisp.h"
  22 #include "mem_limits.h"
  23
  24 /*
  25   Level number of warnings already issued.
  26   0 -- no warnings issued.
  27   1 -- 75% warning already issued.
  28   2 -- 85% warning already issued.
  29 */
  30 static int warnlevel;
  31
  32 /* Function to call to issue a warning;
  33    0 means don't issue them.  */
  34 static void (*warnfunction) ();
  35
  36 extern POINTER sbrk ();
  37
  38 /* Get more memory space, complaining if we're near the end. */
  39
  40 static POINTER
  41 morecore_with_warning (size)
  42      register int size;
  43 {
  44   POINTER result;
  45   register POINTER cp;
  46   register unsigned int siz;
  47
  48   if (!data_space_start)
  49     {
  50       data_space_start = start_of_data ();
  51     }
  52
  53   if (lim_data == 0)
  54     get_lim_data ();
  55
  56   /* Find current end of memory and issue warning if getting near max */
  57   cp = sbrk (0);
  58   siz = cp - data_space_start;
  59
  60   if (warnfunction)
  61     switch (warnlevel)
  62       {
  63       case 0:
  64         if (siz > (lim_data / 4) * 3)
  65           {
  66             warnlevel++;
  67             (*warnfunction) ("Warning: past 75% of memory limit");
  68           }
  69         break;
  70
  71       case 1:
  72         if (siz > (lim_data / 20) * 17)
  73           {
  74             warnlevel++;
  75             (*warnfunction) ("Warning: past 85% of memory limit");
  76           }
  77         break;
  78
  79       case 2:
  80         if (siz > (lim_data / 20) * 19)
  81           {
  82             warnlevel++;
  83             (*warnfunction) ("Warning: past 95% of memory limit");
  84           }
  85         break;
  86
  87       default:
  88         (*warnfunction) ("Warning: past acceptable memory limits");
  89         break;
  90       }
  91
  92   if (EXCEEDS_ELISP_PTR (cp))
  93     (*warnfunction) ("Warning: memory in use exceeds lisp pointer size");
  94
  95   result = sbrk (size);
  96   if (result == (POINTER) -1)
  97     return NULL;
  98   return result;
  99 }
 100
 101 /* Cause reinitialization based on job parameters;
 102    also declare where the end of pure storage is. */
 103
 104 void
 105 malloc_init (start, warnfun)
 106      POINTER start;
 107      void (*warnfun) ();
 108 {
 109   extern POINTER (* __morecore) ();     /* From gmalloc.c */
 110
 111   if (start)
 112     data_space_start = start;
 113   lim_data = 0;
 114   warnlevel = 0;
 115   warnfunction = warnfun;
 116   __morecore = &morecore_with_warning;
 117 }