159 lines
3.6 KiB
Go
159 lines
3.6 KiB
Go
// +build linux
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/*
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Copyright The containerd 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 v1
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import (
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"sync"
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"sync/atomic"
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"golang.org/x/sys/unix"
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"github.com/containerd/cgroups"
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metrics "github.com/docker/go-metrics"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/sirupsen/logrus"
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)
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func newOOMCollector(ns *metrics.Namespace) (*oomCollector, error) {
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fd, err := unix.EpollCreate1(unix.EPOLL_CLOEXEC)
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if err != nil {
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return nil, err
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}
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var desc *prometheus.Desc
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if ns != nil {
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desc = ns.NewDesc("memory_oom", "The number of times a container has received an oom event", metrics.Total, "container_id", "namespace")
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}
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c := &oomCollector{
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fd: fd,
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desc: desc,
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set: make(map[uintptr]*oom),
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}
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if ns != nil {
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ns.Add(c)
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}
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go c.start()
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return c, nil
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}
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type oomCollector struct {
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mu sync.Mutex
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desc *prometheus.Desc
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fd int
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set map[uintptr]*oom
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}
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type oom struct {
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// count needs to stay the first member of this struct to ensure 64bits
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// alignment on a 32bits machine (e.g. arm32). This is necessary as we use
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// the sync/atomic operations on this field.
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count int64
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id string
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namespace string
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c cgroups.Cgroup
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triggers []Trigger
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}
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func (o *oomCollector) Add(id, namespace string, cg cgroups.Cgroup, triggers ...Trigger) error {
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o.mu.Lock()
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defer o.mu.Unlock()
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fd, err := cg.OOMEventFD()
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if err != nil {
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return err
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}
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o.set[fd] = &oom{
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id: id,
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c: cg,
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triggers: triggers,
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namespace: namespace,
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}
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event := unix.EpollEvent{
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Fd: int32(fd),
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Events: unix.EPOLLHUP | unix.EPOLLIN | unix.EPOLLERR,
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}
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return unix.EpollCtl(o.fd, unix.EPOLL_CTL_ADD, int(fd), &event)
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}
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func (o *oomCollector) Describe(ch chan<- *prometheus.Desc) {
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ch <- o.desc
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}
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func (o *oomCollector) Collect(ch chan<- prometheus.Metric) {
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o.mu.Lock()
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defer o.mu.Unlock()
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for _, t := range o.set {
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c := atomic.LoadInt64(&t.count)
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ch <- prometheus.MustNewConstMetric(o.desc, prometheus.CounterValue, float64(c), t.id, t.namespace)
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}
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}
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// Close closes the epoll fd
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func (o *oomCollector) Close() error {
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return unix.Close(o.fd)
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}
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func (o *oomCollector) start() {
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var events [128]unix.EpollEvent
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for {
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n, err := unix.EpollWait(o.fd, events[:], -1)
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if err != nil {
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if err == unix.EINTR {
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continue
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}
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logrus.WithError(err).Error("cgroups: epoll wait failed, OOM notifications disabled")
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return
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}
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for i := 0; i < n; i++ {
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o.process(uintptr(events[i].Fd), events[i].Events)
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}
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}
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}
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func (o *oomCollector) process(fd uintptr, event uint32) {
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// make sure to always flush the fd
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flush(fd)
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o.mu.Lock()
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info, ok := o.set[fd]
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if !ok {
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o.mu.Unlock()
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return
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}
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o.mu.Unlock()
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// if we received an event but it was caused by the cgroup being deleted and the fd
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// being closed make sure we close our copy and remove the container from the set
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if info.c.State() == cgroups.Deleted {
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o.mu.Lock()
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delete(o.set, fd)
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o.mu.Unlock()
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unix.Close(int(fd))
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return
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}
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atomic.AddInt64(&info.count, 1)
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for _, t := range info.triggers {
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t(info.id, info.namespace, info.c)
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}
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}
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func flush(fd uintptr) error {
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var buf [8]byte
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_, err := unix.Read(int(fd), buf[:])
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return err
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}
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