gnu/lib/libmalloc/vm-limit.c

   1 /* Functions for memory limit warnings.
   2    Copyright (C) 1990, 1992 Free Software Foundation, Inc.
   3
   4
   5 This file is part of the GNU C Library.
   6
   7 The GNU C Library is free software; you can redistribute it and/or
   8 modify it under the terms of the GNU Library General Public License as
   9 published by the Free Software Foundation; either version 2 of the
  10 License, or (at your option) any later version.
  11
  12 The GNU C Library 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 GNU
  15 Library General Public License for more details.
  16
  17 You should have received a copy of the GNU Library General Public
  18 License along with the GNU C Library; see the file COPYING.LIB.  If
  19 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  20 Cambridge, MA 02139, 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   extern POINTER (*__morecore) ();
  55
  56   register POINTER cp;
  57   int five_percent;
  58   int data_size;
  59
  60   if (lim_data == 0)
  61     get_lim_data ();
  62   five_percent = lim_data / 20;
  63
  64   /* Find current end of memory and issue warning if getting near max */
  65   cp = (char *) (*__morecore) (0);
  66   data_size = (char *) cp - (char *) data_space_start;
  67
  68   if (warn_function)
  69     switch (warnlevel)
  70       {
  71       case 0:
  72         if (data_size > five_percent * 15)
  73           {
  74             warnlevel++;
  75             (*warn_function) ("Warning: past 75% of memory limit");
  76           }
  77         break;
  78
  79       case 1:
  80         if (data_size > five_percent * 17)
  81           {
  82             warnlevel++;
  83             (*warn_function) ("Warning: past 85% of memory limit");
  84           }
  85         break;
  86
  87       case 2:
  88         if (data_size > five_percent * 19)
  89           {
  90             warnlevel++;
  91             (*warn_function) ("Warning: past 95% of memory limit");
  92           }
  93         break;
  94
  95       default:
  96         (*warn_function) ("Warning: past acceptable memory limits");
  97         break;
  98       }
  99
 100   /* If we go down below 70% full, issue another 75% warning
 101      when we go up again.  */
 102   if (data_size < five_percent * 14)
 103     warnlevel = 0;
 104   /* If we go down below 80% full, issue another 85% warning
 105      when we go up again.  */
 106   else if (warnlevel > 1 && data_size < five_percent * 16)
 107     warnlevel = 1;
 108   /* If we go down below 90% full, issue another 95% warning
 109      when we go up again.  */
 110   else if (warnlevel > 2 && data_size < five_percent * 18)
 111     warnlevel = 2;
 112
 113   if (EXCEEDS_LISP_PTR (cp))
 114     (*warn_function) ("Warning: memory in use exceeds lisp pointer size");
 115 }
 116
 117 /* Cause reinitialization based on job parameters;
 118    also declare where the end of pure storage is. */
 119
 120 void
 121 memory_warnings (start, warnfun)
 122      POINTER start;
 123      void (*warnfun) ();
 124 {
 125   extern void (* __after_morecore_hook) ();     /* From gmalloc.c */
 126
 127   if (start)
 128     data_space_start = start;
 129   else
 130     data_space_start = start_of_data ();
 131
 132   warn_function = warnfun;
 133   __after_morecore_hook = check_memory_limits;
 134 }