lib/physmem.c

   1 /* Calculate the size of physical memory.
   2
   3    Copyright (C) 2000-2001, 2003, 2005-2006, 2009-2025 Free Software
   4    Foundation, Inc.
   5
   6    This file is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation; either version 2.1 of the
   9    License, or (at your option) any later version.
  10
  11    This file 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 Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public License
  17    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  18
  19 /* Written by Paul Eggert.  */
  20
  21 #include <config.h>
  22
  23 #include "physmem.h"
  24
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <unistd.h>
  28
  29 #if HAVE_SYS_PSTAT_H /* HP-UX */
  30 # include <sys/pstat.h>
  31 #endif
  32
  33 #if HAVE_SYS_SYSMP_H /* IRIX */
  34 # include <sys/sysmp.h>
  35 #endif
  36
  37 #if HAVE_SYS_SYSINFO_H
  38 /* Linux, AIX, HP-UX, IRIX, OSF/1, Solaris, Cygwin, Android */
  39 # include <sys/sysinfo.h>
  40 #endif
  41
  42 #if HAVE_MACHINE_HAL_SYSINFO_H /* OSF/1 */
  43 # include <machine/hal_sysinfo.h>
  44 #endif
  45
  46 #if HAVE_SYS_TABLE_H /* OSF/1 */
  47 # include <sys/table.h>
  48 #endif
  49
  50 #include <sys/types.h>
  51
  52 #if HAVE_SYS_PARAM_H
  53 # include <sys/param.h>
  54 #endif
  55
  56 #if HAVE_SYS_SYSCTL_H && !(defined __GLIBC__ && defined __linux__)
  57 /* Linux/musl, macOS, *BSD, IRIX, Minix */
  58 # include <sys/sysctl.h>
  59 #endif
  60
  61 #if HAVE_SYS_SYSTEMCFG_H /* AIX */
  62 # include <sys/systemcfg.h>
  63 #endif
  64
  65 #include "full-read.h"
  66
  67 #ifdef _WIN32
  68
  69 # define WIN32_LEAN_AND_MEAN
  70 # include <windows.h>
  71
  72 /* Don't assume that UNICODE is not defined.  */
  73 # undef GetModuleHandle
  74 # define GetModuleHandle GetModuleHandleA
  75
  76 /* Avoid warnings from gcc -Wcast-function-type.  */
  77 # define GetProcAddress \
  78    (void *) GetProcAddress
  79
  80 /*  MEMORYSTATUSEX is missing from older windows headers, so define
  81     a local replacement.  */
  82 typedef struct
  83 {
  84   DWORD dwLength;
  85   DWORD dwMemoryLoad;
  86   DWORDLONG ullTotalPhys;
  87   DWORDLONG ullAvailPhys;
  88   DWORDLONG ullTotalPageFile;
  89   DWORDLONG ullAvailPageFile;
  90   DWORDLONG ullTotalVirtual;
  91   DWORDLONG ullAvailVirtual;
  92   DWORDLONG ullAvailExtendedVirtual;
  93 } lMEMORYSTATUSEX;
  94 typedef BOOL (WINAPI *PFN_MS_EX) (lMEMORYSTATUSEX*);
  95
  96 #endif
  97
  98 #define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
  99
 100 /* Return the total amount of physical memory.  */
 101 double
 102 physmem_total (void)
 103 {
 104 #if defined _SC_PHYS_PAGES && defined _SC_PAGESIZE
 105   { /* This works on linux-gnu, kfreebsd-gnu, solaris2, and cygwin.  */
 106     double pages = sysconf (_SC_PHYS_PAGES);
 107     double pagesize = sysconf (_SC_PAGESIZE);
 108     if (0 <= pages && 0 <= pagesize)
 109       return pages * pagesize;
 110   }
 111 #endif
 112
 113 #if HAVE_SYSINFO && HAVE_STRUCT_SYSINFO_MEM_UNIT
 114   { /* This works on linux.  */
 115     struct sysinfo si;
 116     if (sysinfo(&si) == 0)
 117       return (double) si.totalram * si.mem_unit;
 118   }
 119 #endif
 120
 121 #if HAVE_PSTAT_GETSTATIC
 122   { /* This works on hpux11.  */
 123     struct pst_static pss;
 124     if (0 <= pstat_getstatic (&pss, sizeof pss, 1, 0))
 125       {
 126         double pages = pss.physical_memory;
 127         double pagesize = pss.page_size;
 128         if (0 <= pages && 0 <= pagesize)
 129           return pages * pagesize;
 130       }
 131   }
 132 #endif
 133
 134 #if HAVE_SYSMP && defined MP_SAGET && defined MPSA_RMINFO && defined _SC_PAGESIZE
 135   { /* This works on irix6. */
 136     struct rminfo realmem;
 137     if (sysmp (MP_SAGET, MPSA_RMINFO, &realmem, sizeof realmem) == 0)
 138       {
 139         double pagesize = sysconf (_SC_PAGESIZE);
 140         double pages = realmem.physmem;
 141         if (0 <= pages && 0 <= pagesize)
 142           return pages * pagesize;
 143       }
 144   }
 145 #endif
 146
 147 #if HAVE_GETSYSINFO && defined GSI_PHYSMEM
 148   { /* This works on Tru64 UNIX V4/5.  */
 149     int physmem;
 150
 151     if (getsysinfo (GSI_PHYSMEM, (caddr_t) &physmem, sizeof (physmem),
 152                     NULL, NULL, NULL) == 1)
 153       {
 154         double kbytes = physmem;
 155
 156         if (0 <= kbytes)
 157           return kbytes * 1024.0;
 158       }
 159   }
 160 #endif
 161
 162 #if HAVE_SYSCTL && !(defined __GLIBC__ && defined __linux__) && defined HW_PHYSMEM
 163   { /* This works on *bsd, kfreebsd-gnu, and darwin.  */
 164     unsigned int physmem;
 165     size_t len = sizeof physmem;
 166     static int mib[2] = { CTL_HW, HW_PHYSMEM };
 167
 168     if (sysctl (mib, ARRAY_SIZE (mib), &physmem, &len, NULL, 0) == 0
 169         && len == sizeof (physmem))
 170       return (double) physmem;
 171   }
 172 #endif
 173
 174 #if HAVE__SYSTEM_CONFIGURATION
 175   /* This works on AIX.  */
 176   return _system_configuration.physmem;
 177 #endif
 178
 179 #if defined _WIN32
 180   { /* this works on windows */
 181     PFN_MS_EX pfnex;
 182     HMODULE h = GetModuleHandle ("kernel32.dll");
 183
 184     if (!h)
 185       return 0.0;
 186
 187     /*  Use GlobalMemoryStatusEx if available.  */
 188     if ((pfnex = (PFN_MS_EX) GetProcAddress (h, "GlobalMemoryStatusEx")))
 189       {
 190         lMEMORYSTATUSEX lms_ex;
 191         lms_ex.dwLength = sizeof lms_ex;
 192         if (!pfnex (&lms_ex))
 193           return 0.0;
 194         return (double) lms_ex.ullTotalPhys;
 195       }
 196
 197     /*  Fall back to GlobalMemoryStatus which is always available.
 198         but returns wrong results for physical memory > 4GB.  */
 199     else
 200       {
 201         MEMORYSTATUS ms;
 202         GlobalMemoryStatus (&ms);
 203         return (double) ms.dwTotalPhys;
 204       }
 205   }
 206 #endif
 207
 208   /* Guess 64 MB.  It's probably an older host, so guess small.  */
 209   return 64 * 1024 * 1024;
 210 }
 211
 212 #if defined __linux__
 213
 214 /* Get the amount of free memory and of inactive file cache memory, and
 215    return 0.  Upon failure, return -1.  */
 216 static int
 217 get_meminfo (unsigned long long *mem_free_p,
 218              unsigned long long *mem_inactive_file_p)
 219 {
 220   /* While the sysinfo() system call returns mem_total, mem_free, and a few
 221      other numbers, the only way to get mem_inactive_file is by reading
 222      /proc/meminfo.  */
 223   int fd = open ("/proc/meminfo", O_RDONLY);
 224   if (fd >= 0)
 225     {
 226       char buf[4096];
 227       size_t buf_size = full_read (fd, buf, sizeof (buf));
 228       close (fd);
 229       if (buf_size > 0)
 230         {
 231           char *buf_end = buf + buf_size;
 232           unsigned long long mem_free = 0;
 233           unsigned long long mem_inactive_file = 0;
 234
 235           /* Iterate through the lines.  */
 236           char *line = buf;
 237           for (;;)
 238             {
 239               char *p;
 240               for (p = line; p < buf_end; p++)
 241                 if (*p == '\n')
 242                   break;
 243               if (p == buf_end)
 244                 break;
 245               *p = '\0';
 246               if (sscanf (line, "MemFree: %llu kB", &mem_free) == 1)
 247                 {
 248                   mem_free *= 1024;
 249                 }
 250               if (sscanf (line, "Inactive(file): %llu kB", &mem_inactive_file) == 1)
 251                 {
 252                   mem_inactive_file *= 1024;
 253                 }
 254               line = p + 1;
 255             }
 256           if (mem_free > 0 && mem_inactive_file > 0)
 257             {
 258               *mem_free_p = mem_free;
 259               *mem_inactive_file_p = mem_inactive_file;
 260               return 0;
 261             }
 262         }
 263     }
 264   return -1;
 265 }
 266
 267 #endif
 268
 269 /* Return the amount of physical memory that can be claimed, with a given
 270    aggressivity.  */
 271 double
 272 physmem_claimable (double aggressivity)
 273 {
 274 #if defined _SC_AVPHYS_PAGES && defined _SC_PAGESIZE
 275 # if defined __linux__
 276   /* On Linux, sysconf (_SC_AVPHYS_PAGES) returns the amount of "free" memory.
 277      The Linux memory management system attempts to keep only a small amount
 278      of memory (something like 5% to 10%) as free, because memory is better
 279      used in the file cache.
 280      We compute the "claimable" memory as
 281        (free memory) + aggressivity * (inactive memory in the file cache).  */
 282   if (aggressivity > 0.0)
 283     {
 284       unsigned long long mem_free;
 285       unsigned long long mem_inactive_file;
 286       if (get_meminfo (&mem_free, &mem_inactive_file) == 0)
 287         return (double) mem_free + aggressivity * (double) mem_inactive_file;
 288     }
 289 # endif
 290   { /* This works on linux-gnu, kfreebsd-gnu, solaris2, and cygwin.  */
 291     double pages = sysconf (_SC_AVPHYS_PAGES);
 292     double pagesize = sysconf (_SC_PAGESIZE);
 293     if (0 <= pages && 0 <= pagesize)
 294       return pages * pagesize;
 295   }
 296 #endif
 297
 298 #if HAVE_SYSINFO && HAVE_STRUCT_SYSINFO_MEM_UNIT
 299   { /* This works on linux.  */
 300     struct sysinfo si;
 301     if (sysinfo(&si) == 0)
 302       return ((double) si.freeram + si.bufferram) * si.mem_unit;
 303   }
 304 #endif
 305
 306 #if HAVE_PSTAT_GETSTATIC && HAVE_PSTAT_GETDYNAMIC
 307   { /* This works on hpux11.  */
 308     struct pst_static pss;
 309     struct pst_dynamic psd;
 310     if (0 <= pstat_getstatic (&pss, sizeof pss, 1, 0)
 311         && 0 <= pstat_getdynamic (&psd, sizeof psd, 1, 0))
 312       {
 313         double pages = psd.psd_free;
 314         double pagesize = pss.page_size;
 315         if (0 <= pages && 0 <= pagesize)
 316           return pages * pagesize;
 317       }
 318   }
 319 #endif
 320
 321 #if HAVE_SYSMP && defined MP_SAGET && defined MPSA_RMINFO && defined _SC_PAGESIZE
 322   { /* This works on irix6. */
 323     struct rminfo realmem;
 324     if (sysmp (MP_SAGET, MPSA_RMINFO, &realmem, sizeof realmem) == 0)
 325       {
 326         double pagesize = sysconf (_SC_PAGESIZE);
 327         double pages = realmem.availrmem;
 328         if (0 <= pages && 0 <= pagesize)
 329           return pages * pagesize;
 330       }
 331   }
 332 #endif
 333
 334 #if HAVE_TABLE && defined TBL_VMSTATS
 335   { /* This works on Tru64 UNIX V4/5.  */
 336     struct tbl_vmstats vmstats;
 337
 338     if (table (TBL_VMSTATS, 0, &vmstats, 1, sizeof (vmstats)) == 1)
 339       {
 340         double pages = vmstats.free_count;
 341         double pagesize = vmstats.pagesize;
 342
 343         if (0 <= pages && 0 <= pagesize)
 344           return pages * pagesize;
 345       }
 346   }
 347 #endif
 348
 349 #if HAVE_SYSCTL && !(defined __GLIBC__ && defined __linux__) && defined HW_USERMEM
 350   { /* This works on *bsd, kfreebsd-gnu, and darwin.  */
 351     unsigned int usermem;
 352     size_t len = sizeof usermem;
 353     static int mib[2] = { CTL_HW, HW_USERMEM };
 354
 355     if (sysctl (mib, ARRAY_SIZE (mib), &usermem, &len, NULL, 0) == 0
 356         && len == sizeof (usermem))
 357       return (double) usermem;
 358   }
 359 #endif
 360
 361 #if defined _WIN32
 362   { /* this works on windows */
 363     PFN_MS_EX pfnex;
 364     HMODULE h = GetModuleHandle ("kernel32.dll");
 365
 366     if (!h)
 367       return 0.0;
 368
 369     /*  Use GlobalMemoryStatusEx if available.  */
 370     if ((pfnex = (PFN_MS_EX) GetProcAddress (h, "GlobalMemoryStatusEx")))
 371       {
 372         lMEMORYSTATUSEX lms_ex;
 373         lms_ex.dwLength = sizeof lms_ex;
 374         if (!pfnex (&lms_ex))
 375           return 0.0;
 376         return (double) lms_ex.ullAvailPhys;
 377       }
 378
 379     /*  Fall back to GlobalMemoryStatus which is always available.
 380         but returns wrong results for physical memory > 4GB  */
 381     else
 382       {
 383         MEMORYSTATUS ms;
 384         GlobalMemoryStatus (&ms);
 385         return (double) ms.dwAvailPhys;
 386       }
 387   }
 388 #endif
 389
 390   /* Guess 25% of physical memory.  */
 391   return physmem_total () / 4;
 392 }
 393
 394 /* Return the amount of physical memory available.  */
 395 double
 396 physmem_available (void)
 397 {
 398   return physmem_claimable (0.0);
 399 }
 400
 401 #if DEBUG
 402
 403 # include <stdio.h>
 404 # include <stdlib.h>
 405
 406 int
 407 main (void)
 408 {
 409   printf ("%12.f %12.f\n", physmem_total (), physmem_available ());
 410   exit (0);
 411 }
 412
 413 #endif /* DEBUG */
 414
 415 /*
 416 Local Variables:
 417 compile-command: "gcc -DDEBUG -g -O -Wall -W physmem.c"
 418 End:
 419 */