github.com/yandex-cloud/geesefs@v0.40.9/internal/cgroup.go (about) 1 // Copyright 2019 Ka-Hing Cheung 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package internal 16 17 import ( 18 "errors" 19 "io/ioutil" 20 "os" 21 "path/filepath" 22 "strconv" 23 "strings" 24 ) 25 26 const CGROUP_PATH = "/proc/self/cgroup" 27 const CGROUP_FOLDER_PREFIX = "/sys/fs/cgroup/memory" 28 const MEM_LIMIT_FILE_SUFFIX = "/memory.limit_in_bytes" 29 const MEM_USAGE_FILE_SUFFIX = "/memory.usage_in_bytes" 30 31 func getCgroupAvailableMem() (retVal uint64, err error) { 32 // get the memory cgroup for self and send limit - usage for the cgroup 33 34 data, err := ioutil.ReadFile(CGROUP_PATH) 35 if err != nil { 36 log.Debugf("Unable to read file %s error: %s", CGROUP_PATH, err) 37 return 0, err 38 } 39 40 path, err := getMemoryCgroupPath(string(data)) 41 if err != nil { 42 return 0, err 43 } 44 45 // newer version of docker mounts the cgroup memory limit/usage files directly under 46 // /sys/fs/cgroup/memory/ rather than /sys/fs/cgroup/memory/docker/$container_id/ 47 if _, err := os.Stat(filepath.Join(CGROUP_FOLDER_PREFIX, path)); os.IsExist(err) { 48 path = filepath.Join(CGROUP_FOLDER_PREFIX, path) 49 } else { 50 path = filepath.Join(CGROUP_FOLDER_PREFIX) 51 } 52 53 mem_limit, err := readFileAndGetValue(filepath.Join(path, MEM_LIMIT_FILE_SUFFIX)) 54 if err != nil { 55 log.Debugf("Unable to get memory limit from cgroup file %v error: %v", path, err) 56 return 0, err 57 } 58 59 mem_usage, err := readFileAndGetValue(filepath.Join(path, MEM_USAGE_FILE_SUFFIX)) 60 if err != nil { 61 log.Debugf("Unable to get memory usage from cgroup file %v error: %v", path, err) 62 return 0, err 63 } 64 65 return (mem_limit - mem_usage), nil 66 } 67 68 func getMemoryCgroupPath(data string) (string, error) { 69 70 /* 71 Content of /proc/self/cgroup 72 73 11:hugetlb:/ 74 10:memory:/user.slice 75 9:cpuset:/ 76 8:blkio:/user.slice 77 7:perf_event:/ 78 6:net_prio,net_cls:/ 79 5:cpuacct,cpu:/user.slice 80 4:devices:/user.slice 81 3:freezer:/ 82 2:pids:/ 83 1:name=systemd:/user.slice/user-1000.slice/session-1759.scope 84 */ 85 86 dataArray := strings.Split(data, "\n") 87 for index := range dataArray { 88 kvArray := strings.Split(dataArray[index], ":") 89 if len(kvArray) == 3 { 90 if kvArray[1] == "memory" { 91 return kvArray[2], nil 92 } 93 } 94 } 95 96 return "", errors.New("Unable to get memory cgroup path") 97 } 98 99 func readFileAndGetValue(path string) (uint64, error) { 100 data, err := ioutil.ReadFile(path) 101 if err != nil { 102 log.Debugf("Unable to read file %v error: %v", path, err) 103 return 0, err 104 } 105 106 return strconv.ParseUint(strings.TrimSpace(string(data)), 10, 64) 107 }