mirror of
https://github.com/kubernetes-sigs/node-feature-discovery.git
synced 2024-12-14 11:57:51 +00:00
108 lines
2.6 KiB
Go
108 lines
2.6 KiB
Go
/*
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Copyright 2018 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 memory
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import (
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"io/ioutil"
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"log"
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"os"
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"strings"
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"sigs.k8s.io/node-feature-discovery/source"
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)
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// Source implements FeatureSource.
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type Source struct{}
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// Name returns an identifier string for this feature source.
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func (s Source) Name() string { return "memory" }
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// Discover returns feature names for memory: numa if more than one memory node is present.
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func (s Source) Discover() (source.Features, error) {
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features := source.Features{}
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// Detect NUMA
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numa, err := isNuma()
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if err != nil {
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log.Printf("ERROR: failed to detect NUMA topology: %s", err)
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} else if numa {
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features["numa"] = true
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}
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// Detect NVDIMM
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nv, err := detectNvdimm()
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if err != nil {
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log.Printf("ERROR: NVDIMM detection failed: %s", err)
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} else {
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for k, v := range nv {
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features["nv."+k] = v
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}
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}
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return features, nil
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}
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// Detect if the platform has NUMA topology
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func isNuma() (bool, error) {
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// Find out how many nodes are online
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// Multiple nodes is a sign of NUMA
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bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/node/online"))
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if err != nil {
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return false, err
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}
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// File content is expected to be:
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// "0\n" in one-node case
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// "0-K\n" in N-node case where K=N-1
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// presence of newline requires TrimSpace
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if strings.TrimSpace(string(bytes)) != "0" {
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// more than one node means NUMA
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return true, nil
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}
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return false, nil
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}
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// Detect NVDIMM devices and configuration
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func detectNvdimm() (map[string]bool, error) {
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features := make(map[string]bool)
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// Check presence of physical devices
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devices, err := ioutil.ReadDir(source.SysfsDir.Path("class/nd"))
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if err == nil {
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if len(devices) > 0 {
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features["present"] = true
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}
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} else if os.IsNotExist(err) {
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return nil, nil
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} else {
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return nil, err
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}
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// Check presence of DAX-configured regions
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devices, err = ioutil.ReadDir(source.SysfsDir.Path("bus/nd/devices"))
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if err == nil {
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for _, d := range devices {
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if strings.HasPrefix(d.Name(), "dax") {
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features["dax"] = true
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}
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}
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} else {
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log.Printf("WARNING: failed to detect NVDIMM configuration: %s", err)
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}
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return features, nil
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}
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