elf/dl-tunables.list

   1 # Copyright (C) 2016-2022 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 # Allowed attributes for tunables:
  19 #
  20 # type: Defaults to STRING
  21 # minval: Optional minimum acceptable value
  22 # maxval: Optional maximum acceptable value
  23 # env_alias: An alias environment variable
  24 # security_level: Specify security level of the tunable for AT_SECURE binaries.
  25 #                 Valid values are:
  26 #
  27 #            SXID_ERASE: (default) Do not read and do not pass on to
  28 #            child processes.
  29 #            SXID_IGNORE: Do not read, but retain for non-AT_SECURE
  30 #            subprocesses.
  31 #            NONE: Read all the time.
  32
  33 glibc {
  34   malloc {
  35     check {
  36       type: INT_32
  37       minval: 0
  38       maxval: 3
  39       env_alias: MALLOC_CHECK_
  40     }
  41     top_pad {
  42       type: SIZE_T
  43       env_alias: MALLOC_TOP_PAD_
  44       security_level: SXID_IGNORE
  45     }
  46     perturb {
  47       type: INT_32
  48       minval: 0
  49       maxval: 0xff
  50       env_alias: MALLOC_PERTURB_
  51       security_level: SXID_IGNORE
  52     }
  53     mmap_threshold {
  54       type: SIZE_T
  55       env_alias: MALLOC_MMAP_THRESHOLD_
  56       security_level: SXID_IGNORE
  57     }
  58     trim_threshold {
  59       type: SIZE_T
  60       env_alias: MALLOC_TRIM_THRESHOLD_
  61       security_level: SXID_IGNORE
  62     }
  63     mmap_max {
  64       type: INT_32
  65       env_alias: MALLOC_MMAP_MAX_
  66       security_level: SXID_IGNORE
  67       minval: 0
  68     }
  69     arena_max {
  70       type: SIZE_T
  71       env_alias: MALLOC_ARENA_MAX
  72       minval: 1
  73       security_level: SXID_IGNORE
  74     }
  75     arena_test {
  76       type: SIZE_T
  77       env_alias: MALLOC_ARENA_TEST
  78       minval: 1
  79       security_level: SXID_IGNORE
  80     }
  81     tcache_max {
  82       type: SIZE_T
  83     }
  84     tcache_count {
  85       type: SIZE_T
  86     }
  87     tcache_unsorted_limit {
  88       type: SIZE_T
  89     }
  90     mxfast {
  91       type: SIZE_T
  92       minval: 0
  93       security_level: SXID_IGNORE
  94     }
  95     hugetlb {
  96       type: SIZE_T
  97       minval: 0
  98     }
  99   }
 100   cpu {
 101     hwcap_mask {
 102       type: UINT_64
 103       env_alias: LD_HWCAP_MASK
 104       default: HWCAP_IMPORTANT
 105     }
 106   }
 107
 108   elision {
 109     enable {
 110       type: INT_32
 111       minval: 0
 112       maxval: 1
 113     }
 114     skip_lock_busy {
 115       type: INT_32
 116       default: 3
 117       minval: 0
 118     }
 119     skip_lock_internal_abort {
 120       type: INT_32
 121       default: 3
 122       minval: 0
 123     }
 124     skip_lock_after_retries {
 125       type: INT_32
 126       default: 3
 127       minval: 0
 128     }
 129     tries {
 130       type: INT_32
 131       default: 3
 132       minval: 0
 133     }
 134     skip_trylock_internal_abort {
 135       type: INT_32
 136       default: 3
 137       minval: 0
 138     }
 139   }
 140
 141   rtld {
 142     nns {
 143       type: SIZE_T
 144       minval: 1
 145       maxval: 16
 146       default: 4
 147     }
 148     optional_static_tls {
 149       type: SIZE_T
 150       minval: 0
 151       default: 512
 152     }
 153   }
 154
 155   mem {
 156     tagging {
 157       type: INT_32
 158       minval: 0
 159       maxval: 255
 160       security_level: SXID_IGNORE
 161     }
 162   }
 163
 164   rtld {
 165     dynamic_sort {
 166       type: INT_32
 167       minval: 1
 168       maxval: 2
 169       default: 2
 170     }
 171   }
 172 }