From fa1869381301797295dece0aec12435fc902295b Mon Sep 17 00:00:00 2001 From: Giuseppe Scrivano Date: Wed, 19 Jun 2019 11:09:54 +0200 Subject: pkg: new package cgroups provide a package for managing cgroups. This is not supposed to be a complete implementation with all the features supported by cgroups, but it is a minimal implementation designed around what libpod needs and it is currently using. For example, it is currently possible to Apply only the pids limit, as it is used by libpod for stopping containers, any other Apply will just fail. The main goal here is to have a minimal library where we have full control, so we can start playing with cgroup v2. When the need arises, we can add more features. Signed-off-by: Giuseppe Scrivano --- pkg/cgroups/pids.go | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 pkg/cgroups/pids.go (limited to 'pkg/cgroups/pids.go') diff --git a/pkg/cgroups/pids.go b/pkg/cgroups/pids.go new file mode 100644 index 000000000..f37ac7611 --- /dev/null +++ b/pkg/cgroups/pids.go @@ -0,0 +1,62 @@ +package cgroups + +import ( + "fmt" + "io/ioutil" + "os" + "path/filepath" + + spec "github.com/opencontainers/runtime-spec/specs-go" +) + +type pidHandler struct { +} + +func getPidsHandler() *pidHandler { + return &pidHandler{} +} + +// Apply set the specified constraints +func (c *pidHandler) Apply(ctr *CgroupControl, res *spec.LinuxResources) error { + if res.Pids == nil { + return nil + } + if ctr.cgroup2 { + return fmt.Errorf("function not implemented yet") + } + + p := filepath.Join(ctr.getCgroupv1Path(Pids), "pids.max") + return ioutil.WriteFile(p, []byte(fmt.Sprintf("%d\n", res.Pids.Limit)), 0644) +} + +// Create the cgroup +func (c *pidHandler) Create(ctr *CgroupControl) (bool, error) { + if ctr.cgroup2 { + return false, fmt.Errorf("function not implemented yet") + } + return ctr.createCgroupDirectory(Pids) +} + +// Destroy the cgroup +func (c *pidHandler) Destroy(ctr *CgroupControl) error { + return os.Remove(ctr.getCgroupv1Path(Pids)) +} + +// Stat fills a metrics structure with usage stats for the controller +func (c *pidHandler) Stat(ctr *CgroupControl, m *Metrics) error { + var PIDRoot string + + if ctr.cgroup2 { + return fmt.Errorf("function not implemented yet") + } + + PIDRoot := ctr.getCgroupv1Path(Pids) + + current, err := readFileAsUint64(filepath.Join(PIDRoot, "pids.current")) + if err != nil { + return err + } + + m.Pids = PidsMetrics{Current: current} + return nil +} -- cgit v1.2.3-54-g00ecf