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Man Pages


Manual Reference Pages  -  RCTL (8)

NAME

rctl - display and update resource limits database

CONTENTS

Synopsis
Description
Rule Syntax
Subjects
Resources
Actions
Loader Tunables
Exit Status
Examples
See Also
History
Authors
Bugs

SYNOPSIS

rctl [-h] [-n] [filter] rctl -a rule rctl -l [-h] [-n] filter rctl -r filter rctl -u [-h] filter

rctl requires the kernel to be compiled with:



.Cd options RACCT
.Cd options RCTL

DESCRIPTION

When called without options, the rctl command writes currently defined RCTL rules to standard output.

If a filter argument is specified, only rules matching the filter are displayed. The options are as follows:
-a rule
  Add rule to the RCTL database.
-l filter
  Display rules applicable to the process defined by filter. Note that this is different from showing the rules when called without any options, as it shows not just the rules with subject equal to that of process, but also rules for the user, jail, and login class applicable to the process.
-r filter
  Remove rules matching filter from the RCTL database.
-u filter
  Display resource usage for a subject ( process, user, loginclass or jail ) matching the filter.
-h "Human-readable" output. Use unit suffixes: Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte.
-n Display user IDs numerically rather than converting them to a user name.

Modifying rules affects all currently running and future processes matching the rule.

RULE SYNTAX

Syntax for a rule is subject:subject-id:resource:action=amount/per.

subject defines the kind of entity the rule applies to. It can be either process, user, loginclass, or jail.
subject-id
  identifies the subject. It can be a process ID, user name, numerical user ID, login class name from login.conf(5), or jail name.
resource identifies the resource the rule controls. See the RESOURCES section below for details.
action defines what will happen when a process exceeds the allowed amount. See the ACTIONS section below for details.
amount defines how much of the resource a process can use before the defined action triggers. Resources which limit bytes may use prefixes from expand_number(3).
per defines what entity the amount gets accounted for. For example, rule "loginclass:users:vmem:deny=100M/process" means that each process of any user belonging to login class "users" may allocate up to 100MB of virtual memory. Rule "loginclass:users:vmem:deny=100M/user" would mean that for each user belonging to the login class "users", the sum of virtual memory allocated by all the processes of that user will not exceed 100MB. Rule "loginclass:users:vmem:deny=100M/loginclass" would mean that the sum of virtual memory allocated by all processes of all users belonging to that login class will not exceed 100MB.

A valid rule has all those fields specified, except for per, which defaults to the value of subject.

A filter is a rule for which one of more fields other than per is left empty. For example, a filter that matches every rule could be written as ":::=/", or, in short, ":". A filter that matches all the login classes would be "loginclass:". A filter that matches all defined rules for maxproc resource would be "::maxproc".

SUBJECTS

subject      subject-id
process      numerical Process ID
user      user name or numerical User ID
loginclass      login class from
  login.conf(5)
jail      jail name

RESOURCES

resource
cputime      CPU time, in seconds
datasize      data size, in bytes
stacksize      stack size, in bytes
coredumpsize      core dump size, in bytes
memoryuse      resident set size, in bytes
memorylocked      locked memory, in bytes
maxproc      number of processes
openfiles      file descriptor table size
vmemoryuse      address space limit, in bytes
pseudoterminals      number of PTYs
swapuse      swap space that may be reserved or used, in bytes
nthr      number of threads
msgqqueued      number of queued SysV messages
msgqsize      SysV message queue size, in bytes
nmsgq      number of SysV message queues
nsem      number of SysV semaphores
nsemop      number of SysV semaphores modified in a single semop(2) call
nshm      number of SysV shared memory segments
shmsize      SysV shared memory size, in bytes
wallclock      wallclock time, in seconds
pcpu      %CPU, in percents of a single CPU core
 

ACTIONS

action
deny      deny the allocation; not supported for
  cputime and wallclock
log      log a warning to the console
devctl      send notification to
  devd(8) using system = "RCTL", subsystem = "rule", type = "matched"
sig* e.g. sigterm; send a signal to the offending process. See signal(3) for a list of supported signals

Not all actions are supported for all resources. Attempting to add a rule with an action not supported by a given resource will result in error.

LOADER TUNABLES

Tunables can be set at the loader(8) prompt, or loader.conf(5).
kern.racct.enable: 1
  Enable rctl. This defaults to 1, unless
.Cd options RACCT_DEFAULT_TO_DISABLED is set in the kernel configuration file.

EXIT STATUS


.Ex -std

EXAMPLES

Prevent user "joe" from allocating more than 1GB of virtual memory:

    -a user:joe:vmemoryuse:deny=1g

Remove all RCTL rules:

    -r :

Display resource usage information for jail named "www":

    -hu jail:www

Display all the rules applicable to process with PID 512:

    -l process:512

Display all rules:

    rctl

Display all rules matching user "joe":

    user:joe

Display all rules matching login classes:

    loginclass:

SEE ALSO

rctl.conf(5)

HISTORY

The rctl command appeared in
.Fx 9.0 .

AUTHORS


.An -nosplit The rctl was developed by
.An Edward Tomasz Napierala Aq trasz@FreeBSD.org under sponsorship from the FreeBSD Foundation.

BUGS

Limiting memoryuse may kill the machine due to thrashing.
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