1  /* Pthread mutex tunable parameters.
       2     Copyright (C) 2018-2023 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  }