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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #ifdef emacs
  21 #include "config.h"
  22 #include "lisp.h"
  23 #endif
  24
  25 #ifndef emacs
  26 #include <stddef.h>
  27 typedef size_t SIZE;
  28 typedef void *POINTER;
  29 #define EXCEEDS_LISP_PTR(x) 0
  30 #endif
  31
  32 #include "mem-limits.h"
  33
  34 /*
  35   Level number of warnings already issued.
  36   0 -- no warnings issued.
  37   1 -- 75% warning already issued.
  38   2 -- 85% warning already issued.
  39   3 -- 95% warning issued; keep warning frequently.
  40 */
  41 static int warnlevel;
  42
  43 /* Function to call to issue a warning;
  44    0 means don't issue them.  */
  45 static void (*warn_function) ();
  46
  47 /* Get more memory space, complaining if we're near the end. */
  48
  49 static void
  50 check_memory_limits ()
  51 {
  52   extern POINTER (*__morecore) ();
  53
  54   register POINTER cp;
  55   int five_percent;
  56   int data_size;
  57
  58   if (lim_data == 0)
  59     get_lim_data ();
  60   five_percent = lim_data / 20;
  61
  62   /* Find current end of memory and issue warning if getting near max */
  63   cp = (char *) (*__morecore) (0);
  64   data_size = (char *) cp - (char *) data_space_start;
  65
  66   if (warn_function)
  67     switch (warnlevel)
  68       {
  69       case 0:
  70         if (data_size > five_percent * 15)
  71           {
  72             warnlevel++;
  73             (*warn_function) ("Warning: past 75% of memory limit");
  74           }
  75         break;
  76
  77       case 1:
  78         if (data_size > five_percent * 17)
  79           {
  80             warnlevel++;
  81             (*warn_function) ("Warning: past 85% of memory limit");
  82           }
  83         break;
  84
  85       case 2:
  86         if (data_size > five_percent * 19)
  87           {
  88             warnlevel++;
  89             (*warn_function) ("Warning: past 95% of memory limit");
  90           }
  91         break;
  92
  93       default:
  94         (*warn_function) ("Warning: past acceptable memory limits");
  95         break;
  96       }
  97
  98   /* If we go down below 70% full, issue another 75% warning
  99      when we go up again.  */
 100   if (data_size < five_percent * 14)
 101     warnlevel = 0;
 102   /* If we go down below 80% full, issue another 85% warning
 103      when we go up again.  */
 104   else if (warnlevel > 1 && data_size < five_percent * 16)
 105     warnlevel = 1;
 106   /* If we go down below 90% full, issue another 95% warning
 107      when we go up again.  */
 108   else if (warnlevel > 2 && data_size < five_percent * 18)
 109     warnlevel = 2;
 110
 111   if (EXCEEDS_LISP_PTR (cp))
 112     (*warn_function) ("Warning: memory in use exceeds lisp pointer size");
 113 }
 114
 115 /* Cause reinitialization based on job parameters;
 116    also declare where the end of pure storage is. */
 117
 118 void
 119 memory_warnings (start, warnfun)
 120      POINTER start;
 121      void (*warnfun) ();
 122 {
 123   extern void (* __after_morecore_hook) ();     /* From gmalloc.c */
 124
 125   if (start)
 126     data_space_start = start;
 127   else
 128     data_space_start = start_of_data ();
 129
 130   warn_function = warnfun;
 131   __after_morecore_hook = check_memory_limits;
 132 }