lib/physmem.c

   1 /* Calculate the size of physical memory.
   2    Copyright 2000, 2001 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include "physmem.h"
  25
  26 #if HAVE_UNISTD_H
  27 # include <unistd.h>
  28 #endif
  29
  30 #if HAVE_SYS_PSTAT_H
  31 # include <sys/pstat.h>
  32 #endif
  33
  34 /* Return the total amount of physical memory.  */
  35 double
  36 physmem_total (void)
  37 {
  38 #if defined _SC_PHYS_PAGES && defined _SC_PAGESIZE
  39   {
  40     double pages = sysconf (_SC_PHYS_PAGES);
  41     double pagesize = sysconf (_SC_PAGESIZE);
  42     if (0 <= pages && 0 <= pagesize)
  43       return pages * pagesize;
  44   }
  45 #endif
  46
  47 #if HAVE_PSTAT_GETSTATIC
  48   {
  49     struct pst_static pss;
  50     if (0 <= pstat_getstatic (&pss, sizeof pss, 1, 0))
  51       {
  52         double pages = pss.physical_memory;
  53         double pagesize = pss.page_size;
  54         if (0 <= pages && 0 <= pagesize)
  55           return pages * pagesize;
  56       }
  57   }
  58 #endif
  59
  60   /* Guess 64 MB.  It's probably an older host, so guess small.  */
  61   return 64 * 1024 * 1024;
  62 }
  63
  64 /* Return the amount of physical memory available.  */
  65 double
  66 physmem_available (void)
  67 {
  68 #if defined _SC_AVPHYS_PAGES && defined _SC_PAGESIZE
  69   {
  70     double pages = sysconf (_SC_AVPHYS_PAGES);
  71     double pagesize = sysconf (_SC_PAGESIZE);
  72     if (0 <= pages && 0 <= pagesize)
  73       return pages * pagesize;
  74   }
  75 #endif
  76
  77 #if HAVE_PSTAT_GETSTATIC && HAVE_PSTAT_GETDYNAMIC
  78   {
  79     struct pst_static pss;
  80     struct pst_dynamic psd;
  81     if (0 <= pstat_getstatic (&pss, sizeof pss, 1, 0)
  82         && 0 <= pstat_getdynamic (&psd, sizeof psd, 1, 0))
  83       {
  84         double pages = psd.psd_free;
  85         double pagesize = pss.page_size;
  86         if (0 <= pages && 0 <= pagesize)
  87           return pages * pagesize;
  88       }
  89   }
  90 #endif
  91
  92   /* Guess 25% of physical memory.  */
  93   return physmem_total () / 4;
  94 }