nptl/pthread_setschedprio.c

   1 /* Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <sched.h>
  22 #include <string.h>
  23 #include <sched.h>
  24 #include "pthreadP.h"
  25 #include <lowlevellock.h>
  26
  27
  28 int
  29 pthread_setschedprio (threadid, prio)
  30      pthread_t threadid;
  31      int prio;
  32 {
  33   struct pthread *pd = (struct pthread *) threadid;
  34
  35   /* Make sure the descriptor is valid.  */
  36   if (INVALID_TD_P (pd))
  37     /* Not a valid thread handle.  */
  38     return ESRCH;
  39
  40   int result = 0;
  41   struct sched_param param;
  42   param.sched_priority = prio;
  43
  44   lll_lock (pd->lock, LLL_PRIVATE);
  45
  46   /* If the thread should have higher priority because of some
  47      PTHREAD_PRIO_PROTECT mutexes it holds, adjust the priority.  */
  48   if (__builtin_expect (pd->tpp != NULL, 0) && pd->tpp->priomax > prio)
  49     param.sched_priority = pd->tpp->priomax;
  50
  51   /* Try to set the scheduler information.  */
  52   if (__builtin_expect (sched_setparam (pd->tid, &param) == -1, 0))
  53     result = errno;
  54   else
  55     {
  56       /* We succeeded changing the kernel information.  Reflect this
  57          change in the thread descriptor.  */
  58       param.sched_priority = prio;
  59       memcpy (&pd->schedparam, &param, sizeof (struct sched_param));
  60       pd->flags |= ATTR_FLAG_SCHED_SET;
  61     }
  62
  63   lll_unlock (pd->lock, LLL_PRIVATE);
  64
  65   return result;
  66 }