nptl/pthread_setschedprio.c

   1 /* Copyright (C) 2002-2022 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 <sched.h>
  22 #include "pthreadP.h"
  23 #include <lowlevellock.h>
  24 #include <shlib-compat.h>
  25
  26 int
  27 __pthread_setschedprio (pthread_t threadid, int prio)
  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   struct sched_param param;
  38   param.sched_priority = prio;
  39
  40   /* See CREATE THREAD NOTES in nptl/pthread_create.c.  */
  41   lll_lock (pd->lock, LLL_PRIVATE);
  42
  43   /* If the thread should have higher priority because of some
  44      PTHREAD_PRIO_PROTECT mutexes it holds, adjust the priority.  */
  45   if (__builtin_expect (pd->tpp != NULL, 0) && pd->tpp->priomax > prio)
  46     param.sched_priority = pd->tpp->priomax;
  47
  48   /* Try to set the scheduler information.  */
  49   if (__glibc_unlikely (__sched_setparam (pd->tid, &param) == -1))
  50     result = errno;
  51   else
  52     {
  53       /* We succeeded changing the kernel information.  Reflect this
  54          change in the thread descriptor.  */
  55       param.sched_priority = prio;
  56       memcpy (&pd->schedparam, &param, sizeof (struct sched_param));
  57       pd->flags |= ATTR_FLAG_SCHED_SET;
  58     }
  59
  60   lll_unlock (pd->lock, LLL_PRIVATE);
  61
  62   return result;
  63 }
  64 versioned_symbol (libc, __pthread_setschedprio, pthread_setschedprio,
  65                   GLIBC_2_34);
  66
  67 #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_3_4, GLIBC_2_34)
  68 compat_symbol (libpthread, __pthread_setschedprio, pthread_setschedprio,
  69                GLIBC_2_3_4);
  70 #endif