xapian-applications/omega/freemem.cc

   1 /** @file
   2  * @brief determine how much free physical memory there is.
   3  */
   4 /* Copyright (C) 2007,2008,2009,2010,2020 Olly Betts
   5  * Copyright (C) 2008 Lemur Consulting Ltd
   6  *
   7  * This program 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 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program 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 this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  20  */
  21
  22 #include <config.h>
  23
  24 #include "freemem.h"
  25
  26 #include <sys/types.h>
  27 #include <climits>
  28 #include "safeunistd.h"
  29 #ifdef HAVE_SYS_SYSCTL_H
  30 // Linux also has sys/sysctl.h but newer versions give a deprecation warning.
  31 # ifndef __linux__
  32 #  include <sys/sysctl.h>
  33 # endif
  34 #endif
  35 #ifdef HAVE_VM_VM_PARAM_H
  36 # include <vm/vm_param.h>
  37 #endif
  38 #ifdef HAVE_SYS_VMMETER_H
  39 # include <sys/vmmeter.h>
  40 #endif
  41 #ifdef HAVE_SYS_SYSMP_H
  42 # include <sys/sysmp.h>
  43 #endif
  44 #ifdef HAVE_SYS_SYSINFO_H
  45 # include <sys/sysinfo.h>
  46 #endif
  47 #ifdef HAVE_SYS_PSTAT_H
  48 # include <sys/pstat.h>
  49 #endif
  50
  51 #ifdef __WIN32__
  52 # include "safewindows.h"
  53 #endif
  54
  55 /* Tested on:
  56  * Linux, FreeBSD, HP-UX, Microsoft Windows.
  57  */
  58
  59 long
  60 get_free_physical_memory()
  61 {
  62 #ifndef __WIN32__
  63     long pagesize = 1;
  64     long pages = -1;
  65 #if defined(_SC_PAGESIZE) && defined(_SC_PHYS_PAGES)
  66     /* Linux:
  67      * _SC_AVPHYS_PAGES is "available memory", but that excludes memory being
  68      * used by the OS VM cache, which will often be almost all memory which
  69      * isn't otherwise used, so used _SC_PHYS_PAGES which is just memory -
  70      * that's good enough for Omega's use where we really just want to avoid
  71      * runaway filter processes for dragging down the system.
  72      */
  73     pagesize = sysconf(_SC_PAGESIZE);
  74     pages = sysconf(_SC_PHYS_PAGES);
  75 #elif defined HAVE_PSTAT_GETDYNAMIC
  76     /* HP-UX: */
  77     struct pst_dynamic info;
  78     if (pstat_getdynamic(&info, sizeof(info), 1, 0) == 1) {
  79         pagesize = getpagesize();
  80         pages = info.psd_free;
  81     }
  82 #elif defined CTL_VM && (defined VM_TOTAL || defined VM_METER)
  83     /* FreeBSD: */
  84     struct vmtotal vm_info;
  85     int mib[2] = {
  86         CTL_VM,
  87 #ifdef VM_TOTAL
  88         VM_TOTAL
  89 #else
  90         VM_METER
  91 #endif
  92     };
  93     size_t len = sizeof(vm_info);
  94     if (sysctl(mib, 2, &vm_info, &len, NULL, 0) == 0) {
  95         pagesize = getpagesize();
  96         pages = vm_info.t_free;
  97     }
  98 #endif
  99     if (pagesize > 0 && pages > 0) {
 100         long mem = LONG_MAX;
 101         if (pages < LONG_MAX / pagesize) {
 102             mem = pages * pagesize;
 103         }
 104         return mem;
 105     }
 106     return -1;
 107 #else
 108     MEMORYSTATUSEX statex;
 109     statex.dwLength = sizeof(statex);
 110     GlobalMemoryStatusEx(&statex);
 111     return statex.ullAvailPhys;
 112 #endif
 113 }