142 lines
3.1 KiB
Go
142 lines
3.1 KiB
Go
//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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"context"
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"fmt"
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"sync"
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"github.com/containerd/cgroups/v3/cgroup1"
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eventstypes "github.com/containerd/containerd/api/events"
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"github.com/containerd/containerd/log"
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"github.com/containerd/containerd/pkg/oom"
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"github.com/containerd/containerd/runtime"
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"github.com/containerd/containerd/runtime/v2/shim"
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"golang.org/x/sys/unix"
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)
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// New returns an epoll implementation that listens to OOM events
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// from a container's cgroups.
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func New(publisher shim.Publisher) (oom.Watcher, 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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return &epoller{
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fd: fd,
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publisher: publisher,
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set: make(map[uintptr]*item),
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}, nil
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}
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// epoller implementation for handling OOM events from a container's cgroup
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type epoller struct {
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mu sync.Mutex
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fd int
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publisher shim.Publisher
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set map[uintptr]*item
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}
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type item struct {
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id string
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cg cgroup1.Cgroup
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}
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// Close the epoll fd
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func (e *epoller) Close() error {
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return unix.Close(e.fd)
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}
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// Run the epoll loop
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func (e *epoller) Run(ctx context.Context) {
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var events [128]unix.EpollEvent
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for {
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select {
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case <-ctx.Done():
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e.Close()
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return
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default:
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n, err := unix.EpollWait(e.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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log.G(ctx).WithError(err).Error("cgroups: epoll wait")
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}
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for i := 0; i < n; i++ {
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e.process(ctx, uintptr(events[i].Fd))
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}
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}
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}
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}
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// Add cgroups.Cgroup to the epoll monitor
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func (e *epoller) Add(id string, cgx interface{}) error {
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cg, ok := cgx.(cgroup1.Cgroup)
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if !ok {
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return fmt.Errorf("expected cgroups.Cgroup, got: %T", cgx)
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}
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e.mu.Lock()
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defer e.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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e.set[fd] = &item{
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id: id,
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cg: cg,
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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(e.fd, unix.EPOLL_CTL_ADD, int(fd), &event)
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}
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func (e *epoller) process(ctx context.Context, fd uintptr) {
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flush(fd)
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e.mu.Lock()
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i, ok := e.set[fd]
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if !ok {
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e.mu.Unlock()
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return
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}
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e.mu.Unlock()
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if i.cg.State() == cgroup1.Deleted {
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e.mu.Lock()
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delete(e.set, fd)
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e.mu.Unlock()
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unix.Close(int(fd))
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return
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}
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if err := e.publisher.Publish(ctx, runtime.TaskOOMEventTopic, &eventstypes.TaskOOM{
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ContainerID: i.id,
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}); err != nil {
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log.G(ctx).WithError(err).Error("publish OOM event")
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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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