elf/dl-tunables.list

   1 # Copyright (C) 2016-2023 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       default: 131072
  46     }
  47     perturb {
  48       type: INT_32
  49       minval: 0
  50       maxval: 0xff
  51       env_alias: MALLOC_PERTURB_
  52       security_level: SXID_IGNORE
  53     }
  54     mmap_threshold {
  55       type: SIZE_T
  56       env_alias: MALLOC_MMAP_THRESHOLD_
  57       security_level: SXID_IGNORE
  58     }
  59     trim_threshold {
  60       type: SIZE_T
  61       env_alias: MALLOC_TRIM_THRESHOLD_
  62       security_level: SXID_IGNORE
  63     }
  64     mmap_max {
  65       type: INT_32
  66       env_alias: MALLOC_MMAP_MAX_
  67       security_level: SXID_IGNORE
  68       minval: 0
  69     }
  70     arena_max {
  71       type: SIZE_T
  72       env_alias: MALLOC_ARENA_MAX
  73       minval: 1
  74       security_level: SXID_IGNORE
  75     }
  76     arena_test {
  77       type: SIZE_T
  78       env_alias: MALLOC_ARENA_TEST
  79       minval: 1
  80       security_level: SXID_IGNORE
  81     }
  82     tcache_max {
  83       type: SIZE_T
  84     }
  85     tcache_count {
  86       type: SIZE_T
  87     }
  88     tcache_unsorted_limit {
  89       type: SIZE_T
  90     }
  91     mxfast {
  92       type: SIZE_T
  93       minval: 0
  94       security_level: SXID_IGNORE
  95     }
  96     hugetlb {
  97       type: SIZE_T
  98       minval: 0
  99     }
 100   }
 101   cpu {
 102     hwcap_mask {
 103       type: UINT_64
 104       env_alias: LD_HWCAP_MASK
 105       default: HWCAP_IMPORTANT
 106     }
 107   }
 108
 109   elision {
 110     enable {
 111       type: INT_32
 112       minval: 0
 113       maxval: 1
 114     }
 115     skip_lock_busy {
 116       type: INT_32
 117       default: 3
 118       minval: 0
 119     }
 120     skip_lock_internal_abort {
 121       type: INT_32
 122       default: 3
 123       minval: 0
 124     }
 125     skip_lock_after_retries {
 126       type: INT_32
 127       default: 3
 128       minval: 0
 129     }
 130     tries {
 131       type: INT_32
 132       default: 3
 133       minval: 0
 134     }
 135     skip_trylock_internal_abort {
 136       type: INT_32
 137       default: 3
 138       minval: 0
 139     }
 140   }
 141
 142   rtld {
 143     nns {
 144       type: SIZE_T
 145       minval: 1
 146       maxval: 16
 147       default: 4
 148     }
 149     optional_static_tls {
 150       type: SIZE_T
 151       minval: 0
 152       default: 512
 153     }
 154   }
 155
 156   mem {
 157     tagging {
 158       type: INT_32
 159       minval: 0
 160       maxval: 255
 161       security_level: SXID_IGNORE
 162     }
 163   }
 164
 165   rtld {
 166     dynamic_sort {
 167       type: INT_32
 168       minval: 1
 169       maxval: 2
 170       default: 2
 171     }
 172   }
 173
 174   gmon {
 175     minarcs {
 176       type: INT_32
 177       minval: 50
 178       default: 50
 179     }
 180     maxarcs {
 181       type: INT_32
 182       minval: 50
 183       default: 1048576
 184     }
 185   }
 186 }