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RCTL(8) 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 ... 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 dis- played. 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 utilization 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 lo- gin.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 al- lowed amount. See the "ACTIONS" section below for de- tails. 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:vmemo- ryuse: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:vmemo- ryuse:deny=100M/user" would mean that for each user be- longing 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:vmemo- ryuse: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 process numerical Process ID user user name or numerical User ID loginclass login class from login.conf(5) jail jail name RESOURCES 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 se- mop(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 readbps filesystem reads, in bytes per second writebps filesystem writes, in bytes per second readiops filesystem reads, in operations per second writeiops filesystem writes, in operations per second ACTIONS deny deny the allocation; not supported for cputime, wallclock, readbps, writebps, readiops, and writeiops 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 throttle slow down process execution; only supported for readbps, writebps, readiops, and writeiops. 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 utilization 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 cpuset(1), rctl(4), 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. The readiops and writeiops counters are only approximations. Like readbps and writebps, they are calculated in the filesystem layer, where it is dif- ficult or even impossible to observe actual disk device operations. The writebps and writeiops resources generally account for writes to the filesystem cache, not to actual devices. FreeBSD ports 15.quarterly February 26, 2018 RCTL(8)
NAME | SYNOPSIS | DESCRIPTION | RULE SYNTAX | SUBJECTS | RESOURCES | ACTIONS | EXIT STATUS | EXAMPLES | SEE ALSO | HISTORY | AUTHORS | BUGS
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