memory: support cgroup with systemd (#7627) (#7666)

close #7628

Signed-off-by: bufferflies <1045931706@qq.com>

Co-authored-by: bufferflies <1045931706@qq.com>

cmd/pd-server/main.go

@@ -30,6 +30,7 @@ import (
  resource_manager "github.com/tikv/pd/pkg/mcs/resourcemanager/server"
  scheduling "github.com/tikv/pd/pkg/mcs/scheduling/server"
  tso "github.com/tikv/pd/pkg/mcs/tso/server"
+ "github.com/tikv/pd/pkg/memory"
  "github.com/tikv/pd/pkg/schedule/schedulers"
  "github.com/tikv/pd/pkg/swaggerserver"
  "github.com/tikv/pd/pkg/utils/configutil"
@@ -229,7 +230,7 @@ func start(cmd *cobra.Command, args []string, services ...string) {
  }
  // Flushing any buffered log entries
  defer log.Sync()
-
+ memory.InitMemoryHook()
  if len(services) != 0 {
  versioninfo.Log(server.APIServiceMode)
  } else {

pkg/memory/meminfo.go

@@ -52,9 +52,13 @@ func MemTotalNormal() (uint64, error) {
  if time.Since(t) < 60*time.Second {
  return total, nil
  }
+ return totalMem()
+}
+
+func totalMem() (uint64, error) {
  v, err := mem.VirtualMemory()
  if err != nil {
- return v.Total, err
+ return 0, err
  }
  memLimit.set(v.Total, time.Now())
  return v.Total, nil
@@ -182,6 +186,38 @@ func init() {
  mustNil(err)
 }
 
+// InitMemoryHook initializes the memory hook.
+// It is to solve the problem that tidb cannot read cgroup in the systemd.
+// so if we are not in the container, we compare the cgroup memory limit and the physical memory,
+// the cgroup memory limit is smaller, we use the cgroup memory hook.
+// ref https://github.com/pingcap/tidb/pull/48096/
+func InitMemoryHook() {
+ if cgroup.InContainer() {
+ log.Info("use cgroup memory hook because pd is in the container")
+ return
+ }
+ cgroupValue, err := cgroup.GetMemoryLimit()
+ if err != nil {
+ return
+ }
+ physicalValue, err := totalMem()
+ if err != nil {
+ return
+ }
+ if physicalValue > cgroupValue && cgroupValue != 0 {
+ MemTotal = MemTotalCGroup
+ MemUsed = MemUsedCGroup
+ sysutil.RegisterGetMemoryCapacity(MemTotalCGroup)
+ log.Info("use cgroup memory hook", zap.Int64("cgroupMemorySize", int64(cgroupValue)), zap.Int64("physicalMemorySize", int64(physicalValue)))
+ } else {
+ log.Info("use physical memory hook", zap.Int64("cgroupMemorySize", int64(cgroupValue)), zap.Int64("physicalMemorySize", int64(physicalValue)))
+ }
+ _, err = MemTotal()
+ mustNil(err)
+ _, err = MemUsed()
+ mustNil(err)
+}
+
 // InstanceMemUsed returns the memory usage of this process
 func InstanceMemUsed() (uint64, error) {
  used, t := serverMemUsage.get()