Linux v5.2.1 - proc
# SPDX-License-Identifier: GPL-2.0-only
bool "/proc file system support" if EXPERT
This is a virtual file system providing information about the status
of the system. "Virtual" means that it doesn't take up any space on
your hard disk: the files are created on the fly by the kernel when
you try to access them. Also, you cannot read the files with older
version of the program less: you need to use more or cat.
It's totally cool; for example, "cat /proc/interrupts" gives
information about what the different IRQs are used for at the moment
(there is a small number of Interrupt ReQuest lines in your computer
that are used by the attached devices to gain the CPU's attention --
often a source of trouble if two devices are mistakenly configured
to use the same IRQ). The program procinfo to display some
information about your system gathered from the /proc file system.
Before you can use the /proc file system, it has to be mounted,
meaning it has to be given a location in the directory hierarchy.
That location should be /proc. A command such as "mount -t proc proc
/proc" or the equivalent line in /etc/fstab does the job.
The /proc file system is explained in the file
<file:Documentation/filesystems/proc.txt> and on the proc(5) manpage
("man 5 proc").
This option will enlarge your kernel by about 67 KB. Several
programs depend on this, so everyone should say Y here.
bool "/proc/kcore support" if !ARM
depends on PROC_FS && MMU
Provides a virtual ELF core file of the live kernel. This can
be read with gdb and other ELF tools. No modifications can be
made using this mechanism.
bool "/proc/vmcore support"
depends on PROC_FS && CRASH_DUMP
Exports the dump image of crashed kernel in ELF format.
bool "Device Hardware/Firmware Log Collection"
depends on PROC_VMCORE
After kernel panic, device drivers can collect the device
specific snapshot of their hardware or firmware before the
underlying devices are initialized in crash recovery kernel.
Note that the device driver must be present in the crash
recovery kernel's initramfs to collect its underlying device
If you say Y here, the collected device dumps will be added
as ELF notes to /proc/vmcore.
bool "Sysctl support (/proc/sys)" if EXPERT
depends on PROC_FS
The sysctl interface provides a means of dynamically changing
certain kernel parameters and variables on the fly without requiring
a recompile of the kernel or reboot of the system. The primary
interface is through /proc/sys. If you say Y here a tree of
modifiable sysctl entries will be generated beneath the
/proc/sys directory. They are explained in the files
in <file:Documentation/sysctl/>. Note that enabling this
option will enlarge the kernel by at least 8 KB.
As it is generally a good thing, you should say Y here unless
building a kernel for install/rescue disks or your system is very
limited in memory.
depends on PROC_FS && MMU
bool "Enable /proc page monitoring" if EXPERT
Various /proc files exist to monitor process memory utilization:
/proc/pid/smaps, /proc/pid/clear_refs, /proc/pid/pagemap,
/proc/kpagecount, and /proc/kpageflags. Disabling these
interfaces will reduce the size of the kernel by approximately 4kb.
bool "Include /proc/<pid>/task/<tid>/children file"
Provides a fast way to retrieve first level children pids of a task. See
<file:Documentation/filesystems/proc.txt> for more information.
Say Y if you are running any user-space software which takes benefit from
this interface. For example, rkt is such a piece of software.