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Diffstat (limited to 'Documentation/filesystems/devpts.txt')
| -rw-r--r-- | Documentation/filesystems/devpts.txt | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/filesystems/devpts.txt b/Documentation/filesystems/devpts.txt index 68dffd87f9b7..30d2fcb32f72 100644 --- a/Documentation/filesystems/devpts.txt +++ b/Documentation/filesystems/devpts.txt @@ -51,6 +51,15 @@ where 'ns_exec -cm /bin/bash' calls clone() with CLONE_NEWNS flag and execs /bin/bash in the child process. A pty created by the sshd is not visible in the original mount of /dev/pts. +Total count of pty pairs in all instances is limited by sysctls: +kernel.pty.max = 4096 - global limit +kernel.pty.reserve = 1024 - reserve for initial instance +kernel.pty.nr - current count of ptys + +Per-instance limit could be set by adding mount option "max=<count>". +This feature was added in kernel 3.4 together with sysctl kernel.pty.reserve. +In kernels older than 3.4 sysctl kernel.pty.max works as per-instance limit. + User-space changes ------------------ |