nptl/pthread_setschedparam.c

   1 /* Copyright (C) 2002-2024 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <sched.h>
  20 #include <string.h>
  21 #include "pthreadP.h"
  22 #include <lowlevellock.h>
  23
  24
  25 int
  26 __pthread_setschedparam (pthread_t threadid, int policy,
  27                          const struct sched_param *param)
  28 {
  29   struct pthread *pd = (struct pthread *) threadid;
  30
  31   /* Make sure the descriptor is valid.  */
  32   if (INVALID_TD_P (pd))
  33     /* Not a valid thread handle.  */
  34     return ESRCH;
  35
  36   int result = 0;
  37
  38   /* See CREATE THREAD NOTES in nptl/pthread_create.c.  */
  39   lll_lock (pd->lock, LLL_PRIVATE);
  40
  41   struct sched_param p;
  42   const struct sched_param *orig_param = param;
  43
  44   /* If the thread should have higher priority because of some
  45      PTHREAD_PRIO_PROTECT mutexes it holds, adjust the priority.  */
  46   if (__builtin_expect (pd->tpp != NULL, 0)
  47       && pd->tpp->priomax > param->sched_priority)
  48     {
  49       p = *param;
  50       p.sched_priority = pd->tpp->priomax;
  51       param = &p;
  52     }
  53
  54   /* Try to set the scheduler information.  */
  55   if (__builtin_expect (__sched_setscheduler (pd->tid, policy,
  56                                               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       pd->schedpolicy = policy;
  63       memcpy (&pd->schedparam, orig_param, sizeof (struct sched_param));
  64       pd->flags |= ATTR_FLAG_SCHED_SET | ATTR_FLAG_POLICY_SET;
  65     }
  66
  67   lll_unlock (pd->lock, LLL_PRIVATE);
  68
  69   return result;
  70 }
  71 strong_alias (__pthread_setschedparam, pthread_setschedparam)