proc_sys_kernel(5) File Formats Manual proc_sys_kernel(5) /proc/sys/kernel/ - control a range of kernel parameters /proc/sys/kernel/ , , . /proc/sys/kernel/acct : highwater, lowwater frequency. BSD, . , , , lowwater , . , highwater , . frequency ( ). 4, 2 30. , , 2% ; 4%; 30 . /proc/sys/kernel/auto_msgmni (Linux 2.6.27 to Linux 3.18) From Linux 2.6.27 to Linux 3.18, this file was used to control recomputing of the value in /proc/sys/kernel/msgmni upon the addition or removal of memory or upon IPC namespace creation/removal. Echoing "1" into this file enabled msgmni automatic recomputing (and triggered a recomputation of msgmni based on the current amount of available memory and number of IPC namespaces). Echoing "0" disabled automatic recomputing. (Automatic recomputing was also disabled if a value was explicitly assigned to /proc/sys/kernel/msgmni.) The default value in auto_msgmni was 1. Linux 3.19 ( msgmni ), <<0>>. /proc/sys/kernel/cap_last_cap ( Linux 3.2) capabilities(7). /proc/sys/kernel/cap-bound (from Linux 2.2 to Linux 2.6.24) ( ). , execve(2), (AND). Linux 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 This file controls the handling of Ctrl-Alt-Del from the keyboard. When the value in this file is 0, Ctrl-Alt-Del is trapped and sent to the init(1) program to handle a graceful restart. When the value is greater than zero, Linux's reaction to a Vulcan Nerve Pinch (tm) will be an immediate reboot, without even syncing its dirty buffers. Note: when a program (like dosemu) has the keyboard in "raw" mode, the Ctrl-Alt-Del is intercepted by the program before it ever reaches the kernel tty layer, and it's up to the program to decide what to do with it. /proc/sys/kernel/dmesg_restrict ( Linux 2.6.37) , syslog . 0 . 1, syslog ( syslog(2) ). Linux 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 (Yellow Pages). . hostname(1). /proc/sys/kernel/hotplug . /sbin/hotplug. /proc/sys/kernel/htab-reclaim ( Linux 2.4.9.2) ( PowerPC) , PowerPC htab (. Documentation/powerpc/ppc_htab.txt ) , . /proc/sys/kernel/keys/ , . keyrings(7). /proc/sys/kernel/kptr_restrict ( Linux 2.6.38) , /proc . 0 . 1, , %pK, , CAP_SYSLOG. 2, , %pK, , . 1, 0 Linux 2.6.39. Linux 3.4, CAP_SYS_ADMIN . /proc/sys/kernel/l2cr ( PowerPC) , L2 G3. 0, . , . /proc/sys/kernel/modprobe This file contains the pathname for the kernel module loader. The default value is /sbin/modprobe. The file is present only if the kernel is built with the CONFIG_MODULES (CONFIG_KMOD in Linux 2.6.26 and earlier) option enabled. It is described by the Linux kernel source file Documentation/kmod.txt (present only in Linux 2.4 and earlier). /proc/sys/kernel/modules_disabled ( Linux 2.6.31) -, , . 0 ( ), 1 ( ). 1 , - . , CONFIG_MODULES. /proc/sys/kernel/msgmax ( Linux 2.2) , System V. /proc/sys/kernel/msgmni ( Linux 2.4) . /proc/sys/kernel/auto_msgmni. /proc/sys/kernel/msgmnb ( Linux 2.2) , msg_qbytes . msg_qbytes , . /proc/sys/kernel/ngroups_max ( Linux 2.6.4) , . /proc/sys/kernel/ns_last_pid ( Linux 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; , , . watchdog (, , ), 60. /proc/sys/kernel/panic_on_oops ( Linux 2.5.68) , oops BUG. 0, . 1, ( klogd oops) panic. /proc/sys/kernel/panic , . /proc/sys/kernel/pid_max ( Linux 2.5.34) This file specifies the value at which PIDs wrap around (i.e., the value in this file is one greater than the maximum PID). PIDs greater than this value are not allocated; thus, the value in this file also acts as a system-wide limit on the total number of processes and threads. The default value for this file, 32768, results in the same range of PIDs as on earlier kernels. On 32-bit platforms, 32768 is the maximum value for pid_max. On 64-bit systems, pid_max can be set to any value up to 2^22 (PID_MAX_LIMIT, approximately 4 million). /proc/sys/kernel/powersave-nap ( PowerPC) . Linux-PPC "nap" , "doze". /proc/sys/kernel/printk syslog(2). /proc/sys/kernel/pty ( Linux 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 ( Linux 2.4) , , 128- UUID UUID. /proc/sys/kernel/randomize_va_space ( Linux 2.6.12) (ASLR) ( ASLR). : 0 ASLR. ASLR, norandmaps. 1 mmap(2), VDSO . , , . PIE- . , CONFIG_COMPAT_BRK. 2 ( Linux 2.6.25) . , CONFIG_COMPAT_BRK. /proc/sys/kernel/real-root-dev Linux Documentation/admin-guide/initrd.rst ( Documentation/initrd.txt Linux 4.10). /proc/sys/kernel/reboot-cmd ( Sparc) , , SPARC ROM/Flash. , ? /proc/sys/kernel/rtsig-max (Up to and including Linux 2.6.7; see setrlimit(2)) This file can be used to tune the maximum number of POSIX real-time (queued) signals that can be outstanding in the system. /proc/sys/kernel/rtsig-nr (Up to and including Linux 2.6.7.) This file shows the number of POSIX real-time signals currently queued. /proc/pid/sched_autogroup_enabled ( Linux 2.6.38) sched(7). /proc/sys/kernel/sched_child_runs_first ( Linux 2.6.23) , fork(2) . , (, ). /proc/sys/kernel/sched_rr_timeslice_ms ( Linux 3.9) sched_rr_get_interval(2). /proc/sys/kernel/sched_rt_period_us ( Linux 2.6.25) sched(7). /proc/sys/kernel/sched_rt_runtime_us ( Linux 2.6.25) sched(7). /proc/sys/kernel/seccomp/ (since Linux 4.14) seccomp. seccomp(2). /proc/sys/kernel/sem ( Linux 2.4) 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 ( Linux 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 ( Linux 2.2) System V. /proc/sys/kernel/shmmax ( Linux 2.2) System V . 1 . SHMMAX. /proc/sys/kernel/shmmni ( Linux 2.4) System V. /proc/sys/kernel/sysctl_writes_strict ( Linux 3.16) /proc/sys. : -1 , printk. write(2) , , . 0 ( ) , -1, printk , , 0. 1 /proc/sys. . , . /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. Linux Documentation/admin-guide/sysrq.rst ( Documentation/sysrq.txt Linux 4.10). /proc/sys/kernel/version , : #5 Wed Feb 25 21:49:24 MET 1998 <<#5>> , , . /proc/sys/kernel/threads-max ( Linux 2.3.11) (), . Linux 4.1, , threads-max . 20. FUTEX_TID_MASK (0x3fffffff). threads-max , EINVAL. RAM. ( 1/8) RAM, threads-max . /proc/sys/kernel/yama/ptrace_scope ( Linux 3.5) ptrace(2). /proc/sys/kernel/zero-paged ( PowerPC) . ( ), Linux-PPC , get_free_pages. proc(5), proc_sys(5) () Alexey, Azamat Hackimov , kogamatranslator49 , Darima Kogan , Max Is , Yuri Kozlov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () <>. Linux 6.9.1 2 2024 . proc_sys_kernel(5)