sysdeps/unix/sysv/linux/pthread_setaffinity.c

   1 /* Copyright (C) 2003-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <pthreadP.h>
  21 #include <sysdep.h>
  22 #include <sys/types.h>
  23 #include <shlib-compat.h>
  24
  25
  26 size_t __kernel_cpumask_size attribute_hidden;
  27
  28
  29 /* Determine the size of cpumask_t in the kernel.  */
  30 int
  31 __determine_cpumask_size (pid_t tid)
  32 {
  33   size_t psize;
  34   int res;
  35
  36   for (psize = 128; ; psize *= 2)
  37     {
  38       char buf[psize];
  39       INTERNAL_SYSCALL_DECL (err);
  40
  41       res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, tid, psize, buf);
  42       if (INTERNAL_SYSCALL_ERROR_P (res, err))
  43         {
  44           if (INTERNAL_SYSCALL_ERRNO (res, err) != EINVAL)
  45             return INTERNAL_SYSCALL_ERRNO (res, err);
  46         }
  47       else
  48         break;
  49     }
  50
  51   if (res != 0)
  52     __kernel_cpumask_size = res;
  53
  54   return 0;
  55 }
  56
  57
  58 int
  59 __pthread_setaffinity_new (pthread_t th, size_t cpusetsize,
  60                            const cpu_set_t *cpuset)
  61 {
  62   const struct pthread *pd = (const struct pthread *) th;
  63
  64   INTERNAL_SYSCALL_DECL (err);
  65   int res;
  66
  67   if (__glibc_unlikely (__kernel_cpumask_size == 0))
  68     {
  69       res = __determine_cpumask_size (pd->tid);
  70       if (res != 0)
  71         return res;
  72     }
  73
  74   /* We now know the size of the kernel cpumask_t.  Make sure the user
  75      does not request to set a bit beyond that.  */
  76   for (size_t cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
  77     if (((char *) cpuset)[cnt] != '\0')
  78       /* Found a nonzero byte.  This means the user request cannot be
  79          fulfilled.  */
  80       return EINVAL;
  81
  82   res = INTERNAL_SYSCALL (sched_setaffinity, err, 3, pd->tid, cpusetsize,
  83                           cpuset);
  84
  85 #ifdef RESET_VGETCPU_CACHE
  86   if (!INTERNAL_SYSCALL_ERROR_P (res, err))
  87     RESET_VGETCPU_CACHE ();
  88 #endif
  89
  90   return (INTERNAL_SYSCALL_ERROR_P (res, err)
  91           ? INTERNAL_SYSCALL_ERRNO (res, err)
  92           : 0);
  93 }
  94 versioned_symbol (libpthread, __pthread_setaffinity_new,
  95                   pthread_setaffinity_np, GLIBC_2_3_4);
  96
  97
  98 #if SHLIB_COMPAT (libpthread, GLIBC_2_3_3, GLIBC_2_3_4)
  99 int
 100 __pthread_setaffinity_old (pthread_t th, cpu_set_t *cpuset)
 101 {
 102   /* The old interface by default assumed a 1024 processor bitmap.  */
 103   return __pthread_setaffinity_new (th, 128, cpuset);
 104 }
 105 compat_symbol (libpthread, __pthread_setaffinity_old, pthread_setaffinity_np,
 106                GLIBC_2_3_3);
 107 #endif