cpu: change cfs_quota from u64 to i64

cfs_quota can be set to -1 to indicate no limit

Fixes: #5

Signed-off-by: bin liu <bin@hyper.sh>

tests/cpu.rs

@@ -0,0 +1,61 @@
+// Copyright (c) 2020 And Group
+//
+// SPDX-License-Identifier: Apache-2.0 or MIT
+//
+
+//! Simple unit tests about the CPU control groups system.
+use cgroups::cpu::CpuController;
+use cgroups::error::ErrorKind;
+use cgroups::{Cgroup, CgroupPid, CpuResources, Hierarchy, Resources};
+
+use std::fs;
+
+#[test]
+fn test_cfs_quota_and_periods() {
+    let h = cgroups::hierarchies::auto();
+    let h = Box::new(&*h);
+    let cg = Cgroup::new(h, String::from("test_cfs_quota_and_periods"));
+
+    let cpu_controller: &CpuController = cg.controller_of().unwrap();
+
+    let current_quota = cpu_controller.cfs_quota().unwrap();
+    let current_peroid = cpu_controller.cfs_period().unwrap();
+
+    // verify default value
+    // The default is “max 100000”.
+    assert_eq!(-1, current_quota);
+    assert_eq!(100000, current_peroid);
+
+    // case 1 set quota
+    let r = cpu_controller.set_cfs_quota(2000);
+
+    let current_quota = cpu_controller.cfs_quota().unwrap();
+    let current_peroid = cpu_controller.cfs_period().unwrap();
+    assert_eq!(2000, current_quota);
+    assert_eq!(100000, current_peroid);
+
+    // case 2 set period
+    cpu_controller.set_cfs_period(1000000);
+    let current_quota = cpu_controller.cfs_quota().unwrap();
+    let current_peroid = cpu_controller.cfs_period().unwrap();
+    assert_eq!(2000, current_quota);
+    assert_eq!(1000000, current_peroid);
+
+    // case 3 set both quota and period
+    cpu_controller.set_cfs_quota_and_period(Some(5000), Some(100000));
+
+    let current_quota = cpu_controller.cfs_quota().unwrap();
+    let current_peroid = cpu_controller.cfs_period().unwrap();
+    assert_eq!(5000, current_quota);
+    assert_eq!(100000, current_peroid);
+
+    // case 4 set both quota and period, set quota to -1
+    cpu_controller.set_cfs_quota_and_period(Some(-1), None);
+
+    let current_quota = cpu_controller.cfs_quota().unwrap();
+    let current_peroid = cpu_controller.cfs_period().unwrap();
+    assert_eq!(-1, current_quota);
+    assert_eq!(100000, current_peroid);
+
+    cg.delete();
+}