ee8701aa97
Not closing the FDs manually means we have to rely on garbage collection to run before cgroup FDs are closed. If the system is running a lot of load probes at a high-frequency (i.e. dynamic housekeeping isn't backing off because of load variations), we can end up hitting our FD limit due to keeping around lots of (useless) FDs.
81 lines
2.2 KiB
Go
81 lines
2.2 KiB
Go
// Copyright 2015 Google Inc. All Rights Reserved.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package netlink
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import (
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"fmt"
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"os"
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info "github.com/google/cadvisor/info/v1"
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"github.com/golang/glog"
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)
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type NetlinkReader struct {
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familyId uint16
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conn *Connection
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}
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func New() (*NetlinkReader, error) {
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conn, err := newConnection()
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if err != nil {
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return nil, fmt.Errorf("failed to create a new connection: %s", err)
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}
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id, err := getFamilyId(conn)
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if err != nil {
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return nil, fmt.Errorf("failed to get netlink family id for task stats: %s", err)
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}
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glog.V(4).Infof("Family id for taskstats: %d", id)
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return &NetlinkReader{
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familyId: id,
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conn: conn,
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}, nil
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}
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func (self *NetlinkReader) Stop() {
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if self.conn != nil {
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self.conn.Close()
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}
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}
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func (self *NetlinkReader) Start() error {
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// We do the start setup for netlink in New(). Nothing to do here.
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return nil
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}
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// Returns instantaneous number of running tasks in a group.
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// Caller can use historical data to calculate cpu load.
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// path is an absolute filesystem path for a container under the CPU cgroup hierarchy.
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// NOTE: non-hierarchical load is returned. It does not include load for subcontainers.
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func (self *NetlinkReader) GetCpuLoad(name string, path string) (info.LoadStats, error) {
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if len(path) == 0 {
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return info.LoadStats{}, fmt.Errorf("cgroup path can not be empty!")
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}
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cfd, err := os.Open(path)
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defer cfd.Close()
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if err != nil {
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return info.LoadStats{}, fmt.Errorf("failed to open cgroup path %s: %q", path, err)
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}
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stats, err := getLoadStats(self.familyId, cfd, self.conn)
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if err != nil {
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return info.LoadStats{}, err
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}
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glog.V(4).Infof("Task stats for %q: %+v", path, stats)
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return stats, nil
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}
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