nptl/pthread_mutex_conf.c

   1 /* Pthread mutex tunable parameters.
   2    Copyright (C) 2018-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   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    <https://www.gnu.org/licenses/>.  */
  18
  19 #define TUNABLE_NAMESPACE pthread
  20 #include <pthread_mutex_conf.h>
  21 #include <stdint.h>
  22 #include <stdbool.h>
  23 #include <unistd.h>  /* Get STDOUT_FILENO for _dl_printf.  */
  24 #include <elf/dl-tunables.h>
  25 #include <nptl-stack.h>
  26
  27 struct mutex_config __mutex_aconf =
  28 {
  29   /* The maximum number of times a thread should spin on the lock before
  30   calling into kernel to block.  */
  31   .spin_count = DEFAULT_ADAPTIVE_COUNT,
  32 };
  33 libc_hidden_data_def (__mutex_aconf)
  34
  35 static void
  36 TUNABLE_CALLBACK (set_mutex_spin_count) (tunable_val_t *valp)
  37 {
  38   __mutex_aconf.spin_count = (int32_t) (valp)->numval;
  39 }
  40
  41 static void
  42 TUNABLE_CALLBACK (set_stack_cache_size) (tunable_val_t *valp)
  43 {
  44   __nptl_stack_cache_maxsize = valp->numval;
  45 }
  46
  47 static void
  48 TUNABLE_CALLBACK (set_stack_hugetlb) (tunable_val_t *valp)
  49 {
  50   __nptl_stack_hugetlb = (int32_t) valp->numval;
  51 }
  52
  53 void
  54 __pthread_tunables_init (void)
  55 {
  56   TUNABLE_GET (mutex_spin_count, int32_t,
  57                TUNABLE_CALLBACK (set_mutex_spin_count));
  58   TUNABLE_GET (stack_cache_size, size_t,
  59                TUNABLE_CALLBACK (set_stack_cache_size));
  60   TUNABLE_GET (stack_hugetlb, int32_t,
  61                TUNABLE_CALLBACK (set_stack_hugetlb));
  62 }