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Set the 'cpu.rt_runtime_us' and 'cpu.rt_runtime_us' values of the cpu cgroup 

before trying to move the process into the cgroup.

This is required if runc itself is running in SCHED_RR mode, as it is not
possible to add a process in SCHED_RR mode to a cgroup which hasn't been
assigned any RT bandwidth. And RT bandwidth is not inherited, each new
cgroup starts with 0 b/w.

Signed-off-by: Ben Gray <ben.r.gray@gmail.com>
This commit is contained in:
ben 2016-05-31 09:01:04 +01:00 committed by Ben
parent fa5ce1e2d0
commit 950700e73c
1 changed files with 41 additions and 10 deletions
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51
libcontainer/cgroups/fs/cpu.go
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@ -22,10 +22,48 @@ func (s *CpuGroup) Name() string {
func (s *CpuGroup) Apply(d *cgroupData) error {
// We always want to join the cpu group, to allow fair cpu scheduling
// on a container basis
_, err := d.join("cpu")
path, err := d.path("cpu")
if err != nil && !cgroups.IsNotFound(err) {
return err
}
return s.ApplyDir(path, d.config, d.pid)
}
func (s *CpuGroup) ApplyDir(path string, cgroup *configs.Cgroup, pid int) error {
// This might happen if we have no cpu cgroup mounted.
// Just do nothing and don't fail.
if path == "" {
return nil
}
if err := os.MkdirAll(path, 0755); err != nil {
return err
}
// We should set the real-Time group scheduling settings before moving
// in the process because if the process is already in SCHED_RR mode
// and no RT bandwidth is set, adding it will fail.
if err := s.SetRtSched(path, cgroup); err != nil {
return err
}
// because we are not using d.join we need to place the pid into the procs file
// unlike the other subsystems
if err := writeFile(path, "cgroup.procs", strconv.Itoa(pid)); err != nil {
return err
}
return nil
}
func (s *CpuGroup) SetRtSched(path string, cgroup *configs.Cgroup) error {
if cgroup.Resources.CpuRtPeriod != 0 {
if err := writeFile(path, "cpu.rt_period_us", strconv.FormatInt(cgroup.Resources.CpuRtPeriod, 10)); err != nil {
return err
}
}
if cgroup.Resources.CpuRtRuntime != 0 {
if err := writeFile(path, "cpu.rt_runtime_us", strconv.FormatInt(cgroup.Resources.CpuRtRuntime, 10)); err != nil {
return err
}
}
return nil
}
@ -45,15 +83,8 @@ func (s *CpuGroup) Set(path string, cgroup *configs.Cgroup) error {
return err
}
}
if cgroup.Resources.CpuRtPeriod != 0 {
if err := writeFile(path, "cpu.rt_period_us", strconv.FormatInt(cgroup.Resources.CpuRtPeriod, 10)); err != nil {
return err
}
}
if cgroup.Resources.CpuRtRuntime != 0 {
if err := writeFile(path, "cpu.rt_runtime_us", strconv.FormatInt(cgroup.Resources.CpuRtRuntime, 10)); err != nil {
return err
}
if err := s.SetRtSched(path, cgroup); err != nil {
return err
}
return nil