1 .. SPDX-License-Identifier: GPL-2.0
2
3 =====================
4 The Devpts Filesystem
5 =====================
6
7 Each mount of the devpts filesystem is now dis
8 and their indices allocated in one mount are i
9 and their indices in all other mounts.
10
11 All mounts of the devpts filesystem now create
12 with permissions ``0000``.
13
14 To retain backwards compatibility the a ptmx d
15 created with ``mknod name c 5 2``) when opened
16 of devpts under the name ``pts`` in the same d
17 node.
18
19 As an option instead of placing a ``/dev/ptmx`
20 it is possible to place a symlink to ``/dev/pt
21 to bind mount ``/dev/ptx/ptmx`` to ``/dev/ptmx
22 the devpts filesystem in this manner devpts sh
23 the ``ptmxmode=0666``, or ``chmod 0666 /dev/pt
24
25 Total count of pty pairs in all instances is l
26
27 kernel.pty.max = 4096 - global limit
28 kernel.pty.reserve = 1024 - reserved for
29 kernel.pty.nr - current coun
30
31 Per-instance limit could be set by adding moun
32
33 This feature was added in kernel 3.4 together
34 ``sysctl kernel.pty.reserve``.
35
36 In kernels older than 3.4 sysctl ``kernel.pty.
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