89ea5ac9c1
Fix threshold notifier build tags so the linux version is only built if cgo is enabled, and the unsupported version is built if it's either not linux or not cgo.
122 lines
2.8 KiB
Go
122 lines
2.8 KiB
Go
// +build cgo
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/*
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Copyright 2016 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 eviction
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/*
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#include <sys/eventfd.h>
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*/
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import "C"
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import (
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"fmt"
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"syscall"
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"github.com/golang/glog"
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)
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type memcgThresholdNotifier struct {
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watchfd int
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controlfd int
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eventfd int
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handler thresholdNotifierHandlerFunc
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description string
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}
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var _ ThresholdNotifier = &memcgThresholdNotifier{}
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// NewMemCGThresholdNotifier sends notifications when a cgroup threshold
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// is crossed (in either direction) for a given cgroup attribute
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func NewMemCGThresholdNotifier(path, attribute, threshold, description string, handler thresholdNotifierHandlerFunc) (ThresholdNotifier, error) {
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watchfd, err := syscall.Open(fmt.Sprintf("%s/%s", path, attribute), syscall.O_RDONLY, 0)
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if err != nil {
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return nil, err
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}
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defer func() {
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if err != nil {
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syscall.Close(watchfd)
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}
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}()
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controlfd, err := syscall.Open(fmt.Sprintf("%s/cgroup.event_control", path), syscall.O_WRONLY, 0)
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if err != nil {
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return nil, err
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}
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defer func() {
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if err != nil {
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syscall.Close(controlfd)
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}
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}()
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efd, err := C.eventfd(0, C.EFD_CLOEXEC)
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if err != nil {
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return nil, err
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}
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eventfd := int(efd)
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if eventfd < 0 {
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err = fmt.Errorf("eventfd call failed")
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return nil, err
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}
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defer func() {
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if err != nil {
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syscall.Close(eventfd)
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}
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}()
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glog.V(2).Infof("eviction: setting notification threshold to %s", threshold)
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config := fmt.Sprintf("%d %d %s", eventfd, watchfd, threshold)
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_, err = syscall.Write(controlfd, []byte(config))
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if err != nil {
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return nil, err
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}
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return &memcgThresholdNotifier{
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watchfd: watchfd,
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controlfd: controlfd,
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eventfd: eventfd,
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handler: handler,
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description: description,
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}, nil
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}
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func getThresholdEvents(eventfd int, eventCh chan<- int) {
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for {
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buf := make([]byte, 8)
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_, err := syscall.Read(eventfd, buf)
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if err != nil {
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return
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}
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eventCh <- 0
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}
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}
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func (n *memcgThresholdNotifier) Start(stopCh <-chan struct{}) {
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eventCh := make(chan int, 1)
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go getThresholdEvents(n.eventfd, eventCh)
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for {
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select {
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case <-stopCh:
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glog.V(2).Infof("eviction: stopping threshold notifier")
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syscall.Close(n.watchfd)
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syscall.Close(n.controlfd)
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syscall.Close(n.eventfd)
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close(eventCh)
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return
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case <-eventCh:
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glog.V(2).Infof("eviction: threshold crossed")
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n.handler(n.description)
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}
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}
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}
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