proc_sys_kernel(5) File Formats Manual proc_sys_kernel(5) (NAME) /proc/sys/kernel/ - (DESCRIPTION) /proc/sys/kernel/ . /proc/sys/kernel/acct : highwater lowwater frequency. BSD . () lowwater . highwater . frequency ( ). . . /proc/sys/kernel/auto_msgmni ( 2.6.27 3.18) 2.6.27 3.18 /proc/sys/kernel/msgmni / IPC . "1" msgmni ( msgmni IPC ). "0" . ( /proc/sys/kernel/msgmni .) auto_msgmni . 3.19 ( msgmni ) "0" . /proc/sys/kernel/cap_last_cap ( 3.2) capabilities(7) . /proc/sys/kernel/cap-bound ( 2.2 2.6.24) << >> (capability bounding set) ( ) . execve(2) AND . 2.6.25 capabilities(7) . /proc/sys/kernel/core_pattern core(5) . /proc/sys/kernel/core_pipe_limit core(5) . /proc/sys/kernel/core_uses_pid core(5) . /proc/sys/kernel/ctrl-alt-del Ctrl-Alt-Del . 0 Ctrl-Alt-Del init(1) . . : ( dosemu) ("raw") Ctrl-Alt-Del tty . /proc/sys/kernel/dmesg_restrict ( 2.6.37) syslog . 0 . 1 syslog . ( syslog(2) .) 3.4 CAP_SYS_ADMIN . /proc/sys/kernel/domainname /proc/sys/kernel/hostname NIS/YP domainname(1) hostname(1) : # echo 'darkstar' > /proc/sys/kernel/hostname # echo 'mydomain' > /proc/sys/kernel/domainname : # hostname 'darkstar' # domainname 'mydomain' darkstar.frop.org "darkstar" DNS ( ) "frop.org" NIS ( ) YP ( ) . . hostname(1) . /proc/sys/kernel/hotplug (hotplug policy agent) . /sbin/hotplug . /proc/sys/kernel/htab-reclaim ( 2.4.9.2) ( PowerPC) htab PowerPC ( Documentation/powerpc/ppc_htab.txt ) (idle loop) . /proc/sys/kernel/keys/ . keyrings(7) . /proc/sys/kernel/kptr_restrict ( 2.6.38) /proc . 0 . 1 %pK CAP_SYSLOG . 2 %pK . 1 2.6.39 0 . 3.4 CAP_SYS_ADMIN . /proc/sys/kernel/l2cr ( PowerPC) (L2) G3 . 0 . . /proc/sys/kernel/modprobe . /sbin/modprobe . CONFIG_MODULES (CONFIG_KMOD 2.6.26 ) . Documentation/kmod.txt ( 2.4 ) . /proc/sys/kernel/modules_disabled ( 2.6.31) (toggle) . (0) (1) . 1 (0) . CONFIG_MODULES . /proc/sys/kernel/msgmax ( 2.2) System V . /proc/sys/kernel/msgmni ( 2.4) . /proc/sys/kernel/auto_msgmni. /proc/sys/kernel/msgmnb ( 2.2) msg_qbytes . msg_qbytes . /proc/sys/kernel/ngroups_max ( 2.6.4) . /proc/sys/kernel/ns_last_pid ( 3.3) pid_namespaces(7) . /proc/sys/kernel/ostype /proc/sys/kernel/osrelease /proc/version . /proc/sys/kernel/overflowgid /proc/sys/kernel/overflowuid /proc/sys/fs/overflowgid /proc/sys/fs/overflowuid . /proc/sys/kernel/panic / panic_timeout . (panic) (autoreboot) . () watchdog . /proc/sys/kernel/panic_on_oops ( 2.5.68) oops BUG . 0 . 1 ( klogd oops ) (panic) . /proc/sys/kernel/panic (reboot) . /proc/sys/kernel/pid_max ( 2.5.34) (PID) (wrap around) ( PID ). . 32768 PID . 32768 pid_max . pid_max 2^22 (PID_MAX_LIMIT ) . /proc/sys/kernel/powersave-nap ( PowerPC) . Linux-PPC "nap" "doze" . /proc/sys/kernel/printk syslog(2) . /proc/sys/kernel/pty ( 2.6.4) UNIX 98 ( pts(4) ) . /proc/sys/kernel/pty/max . /proc/sys/kernel/pty/nr . /proc/sys/kernel/random/ /dev/random . random(4) . /proc/sys/kernel/random/uuid ( 2.4) UUID UUID . /proc/sys/kernel/randomize_va_space ( 2.6.12) (ASLR) ( ASLR ) . : 0 ASLR. ASLR norandmaps . 1 mmap(2) (stack) VDSO. . (text segment) PIE . CONFIG_COMPAT_BRK . 2 ( 2.6.25) (heap) . CONFIG_COMPAT_BRK . /proc/sys/kernel/real-root-dev Documentation/admin-guide/initrd.rst . /proc/sys/kernel/reboot-cmd ( Sparc) SPARC ROM/Flash . /proc/sys/kernel/rtsig-max ( 2.6.7 setrlimit(2) ) POSIX () . /proc/sys/kernel/rtsig-nr ( 2.6.7 .) POSIX . /proc/pid/sched_autogroup_enabled ( 2.6.38) sched(7) . /proc/sys/kernel/sched_child_runs_first ( 2.6.23) fork(2) CPU . CPU . ( CPU .) /proc/sys/kernel/sched_rr_timeslice_ms ( 3.9) sched_rr_get_interval(2) . /proc/sys/kernel/sched_rt_period_us ( 2.6.25) sched(7) . /proc/sys/kernel/sched_rt_runtime_us ( 2.6.25) sched(7) . /proc/sys/kernel/seccomp/ ( 4.14) seccomp . seccomp(2) . /proc/sys/kernel/sem ( 2.4) System V IPC . : SEMMSL . SEMMNS . SEMOPM semop(2) . SEMMNI . /proc/sys/kernel/sg-big-buff SCSI (sg) . include/scsi/sg.h SG_BIG_BUFF . . /proc/sys/kernel/shm_rmid_forced ( 3.1) 1 System V . shmctl(2) IPC_RMID ( 0 ). 1 . shmget(2) . 1 System V ( RLIMIT_AS getrlimit(2) ) . 1 0 . 1 System V . /proc/sys/kernel/shmall ( 2.2) System V . /proc/sys/kernel/shmmax ( 2.2) (System V IPC) . . SHMMAX . /proc/sys/kernel/shmmni ( 2.4) System V . /proc/sys/kernel/sysctl_writes_strict ( 3.16) /proc/sys . : -1 printk . write(2) . 0 () -1 printk . 1 /proc/sys. (append) . . /proc/sys 0 write(2) . /proc/sys/kernel/sysrq SysRq . 1 SysRq ( SysRq ). : 0 sysrq 1 sysrq > 1 sysrq : 2 4 (SAK unraw) 8 16 sync 32 64 (term kill oom-kill) 128 / 256 CONFIG_MAGIC_SYSRQ . Documentation/admin-guide/sysrq.rst . /proc/sys/kernel/version : #5 Wed Feb 25 21:49:24 MET 1998 "#5" . /proc/sys/kernel/threads-max ( 2.3.11) () . 4.1 threads-max . 20 . FUTEX_TID_MASK (0x3fffffff) . threads-max EINVAL . RAM . ( ) RAM threads-max . /proc/sys/kernel/yama/ptrace_scope ( 3.5) ptrace(2) . /proc/sys/kernel/zero-paged ( PowerPC) . () Linux-PPC (idle loop) get_free_pages . (SEE ALSO) proc(5) proc_sys(5) Linux man-pages 6.19 2026-02-08 proc_sys_kernel(5)