nptl/pthread_setschedprio.c

   1 /* Copyright (C) 2002, 2003, 2004 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   /* We have to handle cancellation in the following code since we are
  45      locking another threads desriptor.  */
  46   pthread_cleanup_push ((void (*) (void *)) lll_unlock_wake_cb, &pd->lock);
  47
  48   lll_lock (pd->lock);
  49
  50   /* If the thread should have higher priority because of some
  51      PTHREAD_PRIO_PROTECT mutexes it holds, adjust the priority.  */
  52   if (__builtin_expect (pd->tpp != NULL, 0) && pd->tpp->priomax > prio)
  53     param.sched_priority = pd->tpp->priomax;
  54
  55   /* Try to set the scheduler information.  */
  56   if (__builtin_expect (sched_setparam (pd->tid, &param) == -1, 0))
  57     result = errno;
  58   else
  59     {
  60       /* We succeeded changing the kernel information.  Reflect this
  61          change in the thread descriptor.  */
  62       param.sched_priority = prio;
  63       memcpy (&pd->schedparam, &param, sizeof (struct sched_param));
  64       pd->flags |= ATTR_FLAG_SCHED_SET;
  65     }
  66
  67   lll_unlock (pd->lock);
  68
  69   pthread_cleanup_pop (0);
  70
  71   return result;
  72 }