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https://github.com/k3s-io/kubernetes.git
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88 lines
2.4 KiB
Go
88 lines
2.4 KiB
Go
//go:build linux
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// +build linux
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/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package pidlimit
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import (
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"fmt"
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"os"
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"strconv"
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"strings"
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"syscall"
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"time"
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v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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statsapi "k8s.io/kubelet/pkg/apis/stats/v1alpha1"
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)
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// Stats provides basic information about max and current process count
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func Stats() (*statsapi.RlimitStats, error) {
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rlimit := &statsapi.RlimitStats{}
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taskMax := int64(-1)
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// Calculate the mininum of kernel.pid_max and kernel.threads-max as they both specify the
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// system-wide limit on the number of tasks.
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for _, file := range []string{"/proc/sys/kernel/pid_max", "/proc/sys/kernel/threads-max"} {
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if content, err := os.ReadFile(file); err == nil {
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if limit, err := strconv.ParseInt(string(content[:len(content)-1]), 10, 64); err == nil {
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if taskMax == -1 || taskMax > limit {
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taskMax = limit
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}
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}
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}
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}
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// Both reads did not fail.
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if taskMax >= 0 {
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rlimit.MaxPID = &taskMax
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}
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// Prefer to read "/proc/loadavg" when possible because sysinfo(2)
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// returns truncated number when greater than 65538. See
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// https://github.com/kubernetes/kubernetes/issues/107107
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if procs, err := runningTaskCount(); err == nil {
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rlimit.NumOfRunningProcesses = &procs
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} else {
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var info syscall.Sysinfo_t
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syscall.Sysinfo(&info)
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procs := int64(info.Procs)
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rlimit.NumOfRunningProcesses = &procs
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}
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rlimit.Time = v1.NewTime(time.Now())
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return rlimit, nil
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}
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func runningTaskCount() (int64, error) {
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// Example: 1.36 3.49 4.53 2/3518 3715089
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bytes, err := os.ReadFile("/proc/loadavg")
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if err != nil {
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return 0, err
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}
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fields := strings.Fields(string(bytes))
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if len(fields) < 5 {
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return 0, fmt.Errorf("not enough fields in /proc/loadavg")
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}
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subfields := strings.Split(fields[3], "/")
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if len(subfields) != 2 {
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return 0, fmt.Errorf("error parsing fourth field of /proc/loadavg")
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}
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return strconv.ParseInt(subfields[1], 10, 64)
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}
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