rlimit

Resource limits

Examples

Set resource limit

use rlimit::{setrlimit, Resource};

const DEFAULT_SOFT_LIMIT: u64 = 4 * 1024 * 1024;
const DEFAULT_HARD_LIMIT: u64 = 8 * 1024 * 1024;
assert!(Resource::FSIZE.set(DEFAULT_SOFT_LIMIT, DEFAULT_HARD_LIMIT).is_ok());

let soft = 16384;
let hard = soft * 2;
assert!(setrlimit(Resource::NOFILE, soft, hard).is_ok());

Get resource limit

use rlimit::{getrlimit, Resource};

assert!(Resource::NOFILE.get().is_ok());
assert_eq!(getrlimit(Resource::CPU).unwrap(), (rlimit::INFINITY, rlimit::INFINITY));

Increase NOFILE limit

See the example nofile.

You can also use the tools in rlimit::utils.

use rlimit::utils::increase_nofile_limit;
increase_nofile_limit(10240).unwrap();
increase_nofile_limit(u64::MAX).unwrap();

Troubleshoot

Failed to increase NOFILE to hard limit on macOS

On macOS, getrlimit by default reports that the hard limit is unlimited, but there is usually a stricter hard limit discoverable via sysctl (kern.maxfilesperproc). Failing to discover this secret stricter hard limit will cause the call to setrlimit to fail.

rlimit::utils::increase_nofile_limit respects kern.maxfilesperproc.