RCTL(8) 						    BSD System Manager's Manual 						   RCTL(8)

NAME

     rctl -- display and update resource limits database

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:

	   options RACCT
	   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 "login-
		       class: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/login-
		       class" 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 usage, 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.

EXIT STATUS

     The rctl utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

     Prevent user "joe" from allocating more than 1GB of virtual memory:
	   rctl -a user:joe:vmemoryuse:deny=1g

     Remove all RCTL rules:
	   rctl -r :

     Display resource usage information for jail named "www":
	   rctl -hu jail:www

     Display all the rules applicable to process with PID 512:
	   rctl -l process:512

     Display all rules:
	   rctl

     Display all rules matching user "joe":
	   rctl user:joe

     Display all rules matching login classes:
	   rctl loginclass:

SEE ALSO

     rctl.conf(5)

HISTORY

     The rctl command appeared in FreeBSD 9.0.

AUTHORS

     The rctl was developed by Edward Tomasz Napierala <trasz@FreeBSD.org> under sponsorship from the FreeBSD Foundation.

BUGS

     Limiting memoryuse may kill the machine due to thrashing.

BSD
								September 11, 2014							       BSD