elf/dl-tunables.list

   1 # Copyright (C) 2016-2020 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.  Valid values are:
  25 #
  26 #            SXID_ERASE: (default) Don't read for AT_SECURE binaries and
  27 #                        removed so that child processes can't read it.
  28 #            SXID_IGNORE: Don't read for AT_SECURE binaries, but retained for
  29 #                         non-AT_SECURE subprocesses.
  30 #            NONE: Read all the time.
  31
  32 glibc {
  33   malloc {
  34     check {
  35       type: INT_32
  36       minval: 0
  37       maxval: 3
  38       env_alias: MALLOC_CHECK_
  39     }
  40     top_pad {
  41       type: SIZE_T
  42       env_alias: MALLOC_TOP_PAD_
  43       security_level: SXID_IGNORE
  44     }
  45     perturb {
  46       type: INT_32
  47       minval: 0
  48       maxval: 0xff
  49       env_alias: MALLOC_PERTURB_
  50       security_level: SXID_IGNORE
  51     }
  52     mmap_threshold {
  53       type: SIZE_T
  54       env_alias: MALLOC_MMAP_THRESHOLD_
  55       security_level: SXID_IGNORE
  56     }
  57     trim_threshold {
  58       type: SIZE_T
  59       env_alias: MALLOC_TRIM_THRESHOLD_
  60       security_level: SXID_IGNORE
  61     }
  62     mmap_max {
  63       type: INT_32
  64       env_alias: MALLOC_MMAP_MAX_
  65       security_level: SXID_IGNORE
  66     }
  67     arena_max {
  68       type: SIZE_T
  69       env_alias: MALLOC_ARENA_MAX
  70       minval: 1
  71       security_level: SXID_IGNORE
  72     }
  73     arena_test {
  74       type: SIZE_T
  75       env_alias: MALLOC_ARENA_TEST
  76       minval: 1
  77       security_level: SXID_IGNORE
  78     }
  79     tcache_max {
  80       type: SIZE_T
  81     }
  82     tcache_count {
  83       type: SIZE_T
  84     }
  85     tcache_unsorted_limit {
  86       type: SIZE_T
  87     }
  88     mxfast {
  89       type: SIZE_T
  90       minval: 0
  91       security_level: SXID_IGNORE
  92     }
  93   }
  94   cpu {
  95     hwcap_mask {
  96       type: UINT_64
  97       env_alias: LD_HWCAP_MASK
  98       default: HWCAP_IMPORTANT
  99     }
 100   }
 101
 102   elision {
 103     enable {
 104       type: INT_32
 105       minval: 0
 106       maxval: 1
 107     }
 108     skip_lock_busy {
 109       type: INT_32
 110       default: 3
 111     }
 112     skip_lock_internal_abort {
 113       type: INT_32
 114       default: 3
 115     }
 116     skip_lock_after_retries {
 117       type: INT_32
 118       default: 3
 119     }
 120     tries {
 121       type: INT_32
 122       default: 3
 123     }
 124     skip_trylock_internal_abort {
 125       type: INT_32
 126       default: 3
 127     }
 128   }
 129
 130   rtld {
 131     nns {
 132       type: SIZE_T
 133       minval: 1
 134       maxval: 16
 135       default: 4
 136     }
 137     optional_static_tls {
 138       type: SIZE_T
 139       minval: 0
 140       default: 512
 141     }
 142   }
 143 }