---
name: "rctl"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/rctl/4"
---

# rctl(4)

resource limits

## NAME

**rctl** – resource limits

## SYNOPSIS

To compile this driver into the kernel, place the following line in the kernel configuration file:

**options RACCT** **options RCTL**

## DESCRIPTION

The **rctl** subsystem provides a flexible resource limits mechanism, controlled by a set of rules that can be added or removed at runtime using the [rctl(8)](/rctl/8.md) management utility.

## LOADER TUNABLES

Tunables can be set at the [loader(8)](/loader/8.md) prompt, or [loader.conf(5)](/loader.conf/5.md).

- *kern.racct.enable:* 1

  Enable **rctl**. This defaults to 1, unless **options RACCT\_DEFAULT\_TO\_DISABLED** is set in the kernel configuration file.

## SYSCTLS

See the *kern.racct* sysctl tree.

## SEE ALSO

[rctl.conf(5)](/rctl.conf/5.md), [rctl(8)](/rctl/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **rctl** subsystem first appeared in FreeBSD 9.0.

## AUTHORS

The **rctl** subsystem was developed by Edward Tomasz Napierala ⟨*trasz@FreeBSD.org*⟩ under sponsorship from the FreeBSD Foundation.