Chapter 2. The

proc

File System

31

2.2.14.

/proc/kmsg

This file is used to hold messages generated by the kernel. These messages are then picked up by other

programs, such as

/sbin/klogd

.

2.2.15.

/proc/ksyms

This file holds the kernel exported symbol definitions used by the module tools to dynamically link

and bind loadable modules.

e003def4 speedo_debug [eepro100]

e003b04c eepro100_init [eepro100]

e00390c0 st_template [st]

e002104c RDINDOOR [megaraid]

e00210a4 callDone [megaraid]

e00226cc megaraid_detect [megaraid]

The first column lists the memory address for the kernel function, the second column refers to the

name of the function, and the last column reveals the name of the loaded module.

2.2.16.

/proc/loadavg

This file provides a look at load average on the processor over time and additional data used by

uptime

and other commands. A sample

/proc/loadavg

file looks similar to this:

0.20 0.18 0.12 1/80 11206

The first three columns measure CPU utilization of the last 1, 5, and 10 minute periods. The fourth

column shows the number of currently running processes and the total number of processes. The last

column displays the last process ID used.

2.2.17.

/proc/locks

This files displays the files currently locked by the kernel. The content of this file contains internal

kernel debugging data and can vary tremendously, depending on the use of the system. A sample

/proc/locks

file for a lightly loaded system looks similar to this:

1: FLOCK

ADVISORY

WRITE 807 03:05:308731 0 EOF c2a260c0 c025aa48 c2a26120

2: POSIX

ADVISORY

WRITE 708 03:05:308720 0 EOF c2a2611c c2a260c4 c025aa48

Each lock has its own line which starts with a unique number. The second column refers to the class

of lock used, with

FLOCK

signifying the older style UNIX file locks from a

flock

system call and

POSIX

representing the newer POSIX locks from the

lockf

system call.

The third column can have two values.

ADVISORY

means that the lock does not prevent other people

from accessing the data; it only prevents other attempts to lock it.

MANDATORY

means that no other

access to the data is permitted while the lock is held. The fourth column reveals whether the lock is

allowing the holder

READ

or

WRITE

access to the file, and the fifth column shows the ID of the process

holding the lock. The sixth column shows the ID of the file being locked, in the format of

MAJOR 

DEVICE:MINOR DEVICE:INODE NUMBER

. The seventh column shows the start and end of the file's

locked region. The remaining columns point to internal kernel data structures used for specialized

debugging and can be ignored.