xapian-applications/omega/freemem.cc

   1 /* freemem.cc: determine how much free physical memory there is.
   2  *
   3  * Copyright (C) 2007,2008,2009,2010 Olly Betts
   4  * Copyright (C) 2008 Lemur Consulting Ltd
   5  *
   6  * This program 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 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program 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 this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22
  23 #include "freemem.h"
  24
  25 #include <sys/types.h>
  26 #include <climits>
  27 #include "safeunistd.h"
  28 #ifdef HAVE_SYS_SYSCTL_H
  29 # include <sys/sysctl.h>
  30 #endif
  31 #ifdef HAVE_VM_VM_PARAM_H
  32 # include <vm/vm_param.h>
  33 #endif
  34 #ifdef HAVE_SYS_VMMETER_H
  35 # include <sys/vmmeter.h>
  36 #endif
  37 #ifdef HAVE_SYS_SYSMP_H
  38 # include <sys/sysmp.h>
  39 #endif
  40 #ifdef HAVE_SYS_SYSINFO_H
  41 # include <sys/sysinfo.h>
  42 #endif
  43 #ifdef HAVE_SYS_PSTAT_H
  44 # include <sys/pstat.h>
  45 #endif
  46
  47 #ifdef __WIN32__
  48 # include "safewindows.h"
  49 #endif
  50
  51 /* Tested on:
  52  * Linux, FreeBSD, IRIX, HP-UX, Microsoft Windows.
  53  */
  54
  55 long
  56 get_free_physical_memory()
  57 {
  58 #ifndef __WIN32__
  59     long pagesize = 1;
  60     long pages = -1;
  61 #if defined(_SC_PAGESIZE) && defined(_SC_PHYS_PAGES)
  62     /* Linux:
  63      * _SC_AVPHYS_PAGES is "available memory", but that excludes memory being
  64      * used by the OS VM cache, which will often be almost all memory which
  65      * isn't otherwise used, so used _SC_PHYS_PAGES which is just memory -
  66      * that's good enough for Omega's use where we really just want to avoid
  67      * runaway filter processes for dragging down the system.
  68      */
  69     pagesize = sysconf(_SC_PAGESIZE);
  70     pages = sysconf(_SC_PHYS_PAGES);
  71 #elif defined HAVE_SYSMP
  72     /* IRIX: (rminfo64 and MPSA_RMINFO64?) */
  73     struct rminfo meminfo;
  74     if (sysmp(MP_SAGET, MPSA_RMINFO, &meminfo, sizeof(meminfo)) == 0) {
  75         pagesize = sysconf(_SC_PAGESIZE);
  76         pages = meminfo.availrmem;
  77     }
  78 #elif defined HAVE_PSTAT_GETDYNAMIC
  79     /* HP-UX: */
  80     struct pst_dynamic info;
  81     if (pstat_getdynamic(&info, sizeof(info), 1, 0) == 1) {
  82         pagesize = getpagesize();
  83         pages = info.psd_free;
  84     }
  85 #elif defined CTL_VM && (defined VM_TOTAL || defined VM_METER)
  86     /* FreeBSD: */
  87     struct vmtotal vm_info;
  88     int mib[2] = {
  89         CTL_VM,
  90 #ifdef VM_TOTAL
  91         VM_TOTAL
  92 #else
  93         VM_METER
  94 #endif
  95     };
  96     size_t len = sizeof(vm_info);
  97     if (sysctl(mib, 2, &vm_info, &len, NULL, 0) == 0) {
  98         pagesize = getpagesize();
  99         pages = vm_info.t_free;
 100     }
 101 #endif
 102     if (pagesize > 0 && pages > 0) {
 103         long mem = LONG_MAX;
 104         if (pages < LONG_MAX / pagesize) {
 105             mem = pages * pagesize;
 106         }
 107         return mem;
 108     }
 109     return -1;
 110 #else
 111     MEMORYSTATUSEX statex;
 112     statex.dwLength = sizeof(statex);
 113     GlobalMemoryStatusEx(&statex);
 114     return statex.ullAvailPhys;
 115 #endif
 116 }