src/vm-limit.c

   1 /* Functions for memory limit warnings.
   2    Copyright (C) 1990, 1992, 2002, 2003, 2004,
   3                  2005 Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs; see the file COPYING.  If not, write to
  19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, USA.  */
  21
  22 #ifdef emacs
  23 #include <config.h>
  24 #include "lisp.h"
  25 #endif
  26
  27 #ifndef emacs
  28 #include <stddef.h>
  29 typedef size_t SIZE;
  30 typedef void *POINTER;
  31 #define EXCEEDS_LISP_PTR(x) 0
  32 #endif
  33
  34 #include "mem-limits.h"
  35
  36 /*
  37   Level number of warnings already issued.
  38   0 -- no warnings issued.
  39   1 -- 75% warning already issued.
  40   2 -- 85% warning already issued.
  41   3 -- 95% warning issued; keep warning frequently.
  42 */
  43 static int warnlevel;
  44
  45 /* Function to call to issue a warning;
  46    0 means don't issue them.  */
  47 static void (*warn_function) ();
  48
  49 /* Get more memory space, complaining if we're near the end. */
  50
  51 static void
  52 check_memory_limits ()
  53 {
  54 #ifdef REL_ALLOC
  55   extern POINTER (*real_morecore) ();
  56 #endif
  57   extern POINTER (*__morecore) ();
  58
  59
  60   register POINTER cp;
  61   unsigned long five_percent;
  62   unsigned long data_size;
  63
  64   if (lim_data == 0)
  65     get_lim_data ();
  66   five_percent = lim_data / 20;
  67
  68   /* Find current end of memory and issue warning if getting near max */
  69 #ifdef REL_ALLOC
  70   if (real_morecore)
  71     cp = (char *) (*real_morecore) (0);
  72   else
  73 #endif
  74   cp = (char *) (*__morecore) (0);
  75   data_size = (char *) cp - (char *) data_space_start;
  76
  77   if (warn_function)
  78     switch (warnlevel)
  79       {
  80       case 0:
  81         if (data_size > five_percent * 15)
  82           {
  83             warnlevel++;
  84             (*warn_function) ("Warning: past 75% of memory limit");
  85           }
  86         break;
  87
  88       case 1:
  89         if (data_size > five_percent * 17)
  90           {
  91             warnlevel++;
  92             (*warn_function) ("Warning: past 85% of memory limit");
  93           }
  94         break;
  95
  96       case 2:
  97         if (data_size > five_percent * 19)
  98           {
  99             warnlevel++;
 100             (*warn_function) ("Warning: past 95% of memory limit");
 101           }
 102         break;
 103
 104       default:
 105         (*warn_function) ("Warning: past acceptable memory limits");
 106         break;
 107       }
 108
 109   /* If we go down below 70% full, issue another 75% warning
 110      when we go up again.  */
 111   if (data_size < five_percent * 14)
 112     warnlevel = 0;
 113   /* If we go down below 80% full, issue another 85% warning
 114      when we go up again.  */
 115   else if (warnlevel > 1 && data_size < five_percent * 16)
 116     warnlevel = 1;
 117   /* If we go down below 90% full, issue another 95% warning
 118      when we go up again.  */
 119   else if (warnlevel > 2 && data_size < five_percent * 18)
 120     warnlevel = 2;
 121
 122   if (EXCEEDS_LISP_PTR (cp))
 123     (*warn_function) ("Warning: memory in use exceeds lisp pointer size");
 124 }
 125
 126 /* Cause reinitialization based on job parameters;
 127    also declare where the end of pure storage is. */
 128
 129 void
 130 memory_warnings (start, warnfun)
 131      POINTER start;
 132      void (*warnfun) ();
 133 {
 134   extern void (* __after_morecore_hook) ();     /* From gmalloc.c */
 135
 136   if (start)
 137     data_space_start = start;
 138   else
 139     data_space_start = start_of_data ();
 140
 141   warn_function = warnfun;
 142   __after_morecore_hook = check_memory_limits;
 143
 144 #ifdef WINDOWSNT
 145   /* Force data limit to be recalculated on each run.  */
 146   lim_data = 0;
 147 #endif
 148 }
 149
 150 /* arch-tag: eab04eda-1f69-447a-8d9f-95f0a3983ca5
 151    (do not change this comment) */