package cgroup import ( "bytes" "fmt" "io/ioutil" "os" "path/filepath" "strings" ) // Cgroup is the combination of sub-cgroups type Cgroup struct { prefix string cpuset *SubCgroup cpuacct *SubCgroup memory *SubCgroup pids *SubCgroup } // Build creates new cgrouup directories func (b *Builder) Build() (cg *Cgroup, err error) { var ( cpuSetPath, cpuacctPath, memoryPath, pidsPath string ) // if failed, remove potential created directory defer func() { if err != nil { remove(cpuSetPath) remove(cpuacctPath) remove(memoryPath) remove(pidsPath) } }() for _, c := range []struct { enable bool name string path *string }{ {b.CPUSet, "cpuset", &cpuSetPath}, {b.CPUAcct, "cpuacct", &cpuacctPath}, {b.Memory, "memory", &memoryPath}, {b.Pids, "pids", &pidsPath}, } { if !c.enable { continue } if *c.path, err = CreateSubCgroupPath(c.name, b.Prefix); err != nil { return } } if b.CPUSet { if err = initCpuset(cpuSetPath); err != nil { return } } return &Cgroup{ prefix: b.Prefix, cpuset: NewSubCgroup(cpuSetPath), cpuacct: NewSubCgroup(cpuacctPath), memory: NewSubCgroup(memoryPath), pids: NewSubCgroup(pidsPath), }, nil } // AddProc writes cgroup.procs to all sub-cgroup func (c *Cgroup) AddProc(pid int) error { for _, s := range []*SubCgroup{c.cpuset, c.cpuset, c.memory, c.pids} { if err := s.WriteUint(cgroupProcs, uint64(pid)); err != nil { return err } } return nil } // Destroy removes dir for sub-cgroup, errors are ignored if remove one failed func (c *Cgroup) Destroy() error { var err1 error for _, s := range []*SubCgroup{c.cpuset, c.cpuset, c.memory, c.pids} { if err := remove(s.path); err != nil { err1 = err } } return err1 } // SetCpusetCpus set cpuset.cpus func (c *Cgroup) SetCpusetCpus(b []byte) error { return c.cpuset.WriteFile("cpuset.cpus", b) } // SetCpusetMems set cpuset.mems func (c *Cgroup) SetCpusetMems(b []byte) error { return c.cpuset.WriteFile("cpuset.mems", b) } // CpuacctUsage read cpuacct.usage in ns func (c *Cgroup) CpuacctUsage() (uint64, error) { return c.cpuacct.ReadUint("cpuacct.usage") } // MemoryMaxUsageInBytes read memory.max_usage_in_bytes func (c *Cgroup) MemoryMaxUsageInBytes() (uint64, error) { return c.memory.ReadUint("memory.max_usage_in_bytes") } // SetMemoryLimitInBytes write memory.limit_in_bytes func (c *Cgroup) SetMemoryLimitInBytes(i uint64) error { return c.memory.WriteUint("memory.limit_in_bytes", i) } // SetPidsMax write pids.max func (c *Cgroup) SetPidsMax(i uint64) error { return c.pids.WriteUint("pids.max", i) } // SetCpuacctUsage write cpuacct.usage in ns func (c *Cgroup) SetCpuacctUsage(i uint64) error { return c.cpuacct.WriteUint("cpuacct.usage", i) } // SetMemoryMaxUsageInBytes write cpuacct.usage in ns func (c *Cgroup) SetMemoryMaxUsageInBytes(i uint64) error { return c.memory.WriteUint("memory.max_usage_in_bytes", i) } // FindMemoryStatProperty find certain property from memory.stat func (c *Cgroup) FindMemoryStatProperty(prop string) (uint64, error) { content, err := c.memory.ReadFile("memory.stat") if err != nil { return 0, err } r := bytes.NewReader(content) for { var p string var i uint64 _, err = fmt.Fscanln(r, &p, &i) if err != nil { return 0, err } if p == prop { return i, nil } } } // initCpuset will copy the config from the parent cpu sets if not exists func initCpuset(path string) error { for _, f := range []string{"cpuset.cpus", "cpuset.mems"} { if err := copyCgroupPropertyFromParent(path, f); err != nil { return err } } return nil } func copyCgroupPropertyFromParent(path, name string) error { // ensure current one empty b, err := ioutil.ReadFile(filepath.Join(path, name)) if err != nil { return err } if len(strings.TrimSpace(string(b))) > 0 { return nil } // otherwise copy from parent, first to ensure it is empty by recurssion if err := copyCgroupPropertyFromParent(filepath.Dir(path), name); err != nil { return err } b, err = ioutil.ReadFile(filepath.Join(filepath.Dir(path), name)) if err != nil { return err } return ioutil.WriteFile(filepath.Join(path, name), b, filePerm) } func remove(name string) error { if name != "" { return os.Remove(name) } return nil }