src/vm-limit.c

   1 /* Functions for memory limit warnings.
   2    Copyright (C) 1990, 1992, 2002, 2003, 2004,
   3                  2005, 2006 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 #ifdef HAVE_GETRLIMIT
  37 #include <sys/resource.h>
  38 #endif
  39
  40 /*
  41   Level number of warnings already issued.
  42   0 -- no warnings issued.
  43   1 -- 75% warning already issued.
  44   2 -- 85% warning already issued.
  45   3 -- 95% warning issued; keep warning frequently.
  46 */
  47 static int warnlevel;
  48
  49 /* Function to call to issue a warning;
  50    0 means don't issue them.  */
  51 static void (*warn_function) ();
  52
  53 /* Get more memory space, complaining if we're near the end. */
  54
  55 static void
  56 check_memory_limits ()
  57 {
  58 #ifdef REL_ALLOC
  59   extern POINTER (*real_morecore) ();
  60 #endif
  61   extern POINTER (*__morecore) ();
  62
  63
  64   register POINTER cp;
  65   unsigned long five_percent;
  66   unsigned long data_size;
  67
  68 #ifdef HAVE_GETRLIMIT
  69   struct rlimit {
  70     rlim_t rlim_cur;
  71     rlim_t rlim_max;
  72   } rlimit;
  73
  74   getrlimit (RLIMIT_DATA, &rlimit);
  75
  76   five_percent = rlimit.rlim_max / 20;
  77   data_size = rlimit.rlim_cur;
  78
  79 #else /* not HAVE_GETRLIMIT */
  80
  81   if (lim_data == 0)
  82     get_lim_data ();
  83   five_percent = lim_data / 20;
  84
  85   /* Find current end of memory and issue warning if getting near max */
  86 #ifdef REL_ALLOC
  87   if (real_morecore)
  88     cp = (char *) (*real_morecore) (0);
  89   else
  90 #endif
  91   cp = (char *) (*__morecore) (0);
  92   data_size = (char *) cp - (char *) data_space_start;
  93
  94 #endif /* not HAVE_GETRLIMIT */
  95
  96   if (warn_function)
  97     switch (warnlevel)
  98       {
  99       case 0:
 100         if (data_size > five_percent * 15)
 101           {
 102             warnlevel++;
 103             (*warn_function) ("Warning: past 75% of memory limit");
 104           }
 105         break;
 106
 107       case 1:
 108         if (data_size > five_percent * 17)
 109           {
 110             warnlevel++;
 111             (*warn_function) ("Warning: past 85% of memory limit");
 112           }
 113         break;
 114
 115       case 2:
 116         if (data_size > five_percent * 19)
 117           {
 118             warnlevel++;
 119             (*warn_function) ("Warning: past 95% of memory limit");
 120           }
 121         break;
 122
 123       default:
 124         (*warn_function) ("Warning: past acceptable memory limits");
 125         break;
 126       }
 127
 128   /* If we go down below 70% full, issue another 75% warning
 129      when we go up again.  */
 130   if (data_size < five_percent * 14)
 131     warnlevel = 0;
 132   /* If we go down below 80% full, issue another 85% warning
 133      when we go up again.  */
 134   else if (warnlevel > 1 && data_size < five_percent * 16)
 135     warnlevel = 1;
 136   /* If we go down below 90% full, issue another 95% warning
 137      when we go up again.  */
 138   else if (warnlevel > 2 && data_size < five_percent * 18)
 139     warnlevel = 2;
 140
 141   if (EXCEEDS_LISP_PTR (cp))
 142     (*warn_function) ("Warning: memory in use exceeds lisp pointer size");
 143 }
 144
 145 /* Cause reinitialization based on job parameters;
 146    also declare where the end of pure storage is. */
 147
 148 void
 149 memory_warnings (start, warnfun)
 150      POINTER start;
 151      void (*warnfun) ();
 152 {
 153   extern void (* __after_morecore_hook) ();     /* From gmalloc.c */
 154
 155   if (start)
 156     data_space_start = start;
 157   else
 158     data_space_start = start_of_data ();
 159
 160   warn_function = warnfun;
 161   __after_morecore_hook = check_memory_limits;
 162
 163 #ifdef WINDOWSNT
 164   /* Force data limit to be recalculated on each run.  */
 165   lim_data = 0;
 166 #endif
 167 }
 168
 169 /* arch-tag: eab04eda-1f69-447a-8d9f-95f0a3983ca5
 170    (do not change this comment) */