src/vm-limit.c

   1 /* Functions for memory limit warnings.
   2    Copyright (C) 1990, 1992 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 2, 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, Inc., 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21 #ifdef emacs
  22 #include <config.h>
  23 #include "lisp.h"
  24 #endif
  25
  26 #ifndef emacs
  27 #include <stddef.h>
  28 typedef size_t SIZE;
  29 typedef void *POINTER;
  30 #define EXCEEDS_LISP_PTR(x) 0
  31 #endif
  32
  33 #include "mem-limits.h"
  34
  35 /*
  36   Level number of warnings already issued.
  37   0 -- no warnings issued.
  38   1 -- 75% warning already issued.
  39   2 -- 85% warning already issued.
  40   3 -- 95% warning issued; keep warning frequently.
  41 */
  42 static int warnlevel;
  43
  44 /* Function to call to issue a warning;
  45    0 means don't issue them.  */
  46 static void (*warn_function) ();
  47
  48 /* Get more memory space, complaining if we're near the end. */
  49
  50 static void
  51 check_memory_limits ()
  52 {
  53   extern POINTER (*__morecore) ();
  54
  55   register POINTER cp;
  56   unsigned long five_percent;
  57   unsigned long data_size;
  58
  59   if (lim_data == 0)
  60     get_lim_data ();
  61   five_percent = lim_data / 20;
  62
  63   /* Find current end of memory and issue warning if getting near max */
  64   cp = (char *) (*__morecore) (0);
  65   data_size = (char *) cp - (char *) data_space_start;
  66
  67   if (warn_function)
  68     switch (warnlevel)
  69       {
  70       case 0:
  71         if (data_size > five_percent * 15)
  72           {
  73             warnlevel++;
  74             (*warn_function) ("Warning: past 75% of memory limit");
  75           }
  76         break;
  77
  78       case 1:
  79         if (data_size > five_percent * 17)
  80           {
  81             warnlevel++;
  82             (*warn_function) ("Warning: past 85% of memory limit");
  83           }
  84         break;
  85
  86       case 2:
  87         if (data_size > five_percent * 19)
  88           {
  89             warnlevel++;
  90             (*warn_function) ("Warning: past 95% of memory limit");
  91           }
  92         break;
  93
  94       default:
  95         (*warn_function) ("Warning: past acceptable memory limits");
  96         break;
  97       }
  98
  99   /* If we go down below 70% full, issue another 75% warning
 100      when we go up again.  */
 101   if (data_size < five_percent * 14)
 102     warnlevel = 0;
 103   /* If we go down below 80% full, issue another 85% warning
 104      when we go up again.  */
 105   else if (warnlevel > 1 && data_size < five_percent * 16)
 106     warnlevel = 1;
 107   /* If we go down below 90% full, issue another 95% warning
 108      when we go up again.  */
 109   else if (warnlevel > 2 && data_size < five_percent * 18)
 110     warnlevel = 2;
 111
 112   if (EXCEEDS_LISP_PTR (cp))
 113     (*warn_function) ("Warning: memory in use exceeds lisp pointer size");
 114 }
 115
 116 /* Cause reinitialization based on job parameters;
 117    also declare where the end of pure storage is. */
 118
 119 void
 120 memory_warnings (start, warnfun)
 121      POINTER start;
 122      void (*warnfun) ();
 123 {
 124   extern void (* __after_morecore_hook) ();     /* From gmalloc.c */
 125
 126   if (start)
 127     data_space_start = start;
 128   else
 129     data_space_start = start_of_data ();
 130
 131   warn_function = warnfun;
 132   __after_morecore_hook = check_memory_limits;
 133 }