1
0
Fork 0
mirror of https://github.com/kubernetes-sigs/node-feature-discovery.git synced 2025-03-16 21:38:23 +00:00
node-feature-discovery/source/memory/memory.go
Markus Lehtonen a2b9df5cd3 nfd-worker: rework configuration handling
Extend the FeatureSource interface with new methods for configuration
handling. This enables easier on-the fly reconfiguration of the
feature sources. Further, it simplifies adding config support to feature
sources in the future. Stub methods are added to sources that do not
currently have any configurability.

The patch fixes some (corner) cases with the overrides (--options)
handling, too:
- Overrides were not applied if config file was missing or its parsing
  failed
- Overrides for a certain source did not have effect if an empty config
  for the source was specified in the config file. This was caused by
  the first pass of parsing (config file) setting a nil pointer to the
  source-specific config, effectively detaching it from the main config.
  The second pass would then create a new instance of the source
  specific config, but, this was not visible in the feature source, of
  course.
2020-05-21 00:59:37 +03:00

117 lines
2.9 KiB
Go

/*
Copyright 2018 The Kubernetes Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package memory
import (
"io/ioutil"
"log"
"os"
"strings"
"sigs.k8s.io/node-feature-discovery/source"
)
// Source implements FeatureSource.
type Source struct{}
// Name returns an identifier string for this feature source.
func (s Source) Name() string { return "memory" }
// NewConfig method of the FeatureSource interface
func (s *Source) NewConfig() source.Config { return nil }
// GetConfig method of the FeatureSource interface
func (s *Source) GetConfig() source.Config { return nil }
// SetConfig method of the FeatureSource interface
func (s *Source) SetConfig(source.Config) {}
// Discover returns feature names for memory: numa if more than one memory node is present.
func (s Source) Discover() (source.Features, error) {
features := source.Features{}
// Detect NUMA
numa, err := isNuma()
if err != nil {
log.Printf("ERROR: failed to detect NUMA topology: %s", err)
} else if numa {
features["numa"] = true
}
// Detect NVDIMM
nv, err := detectNvdimm()
if err != nil {
log.Printf("ERROR: NVDIMM detection failed: %s", err)
} else {
for k, v := range nv {
features["nv."+k] = v
}
}
return features, nil
}
// Detect if the platform has NUMA topology
func isNuma() (bool, error) {
// Find out how many nodes are online
// Multiple nodes is a sign of NUMA
bytes, err := ioutil.ReadFile(source.SysfsDir.Path("devices/system/node/online"))
if err != nil {
return false, err
}
// File content is expected to be:
// "0\n" in one-node case
// "0-K\n" in N-node case where K=N-1
// presence of newline requires TrimSpace
if strings.TrimSpace(string(bytes)) != "0" {
// more than one node means NUMA
return true, nil
}
return false, nil
}
// Detect NVDIMM devices and configuration
func detectNvdimm() (map[string]bool, error) {
features := make(map[string]bool)
// Check presence of physical devices
devices, err := ioutil.ReadDir(source.SysfsDir.Path("class/nd"))
if err == nil {
if len(devices) > 0 {
features["present"] = true
}
} else if os.IsNotExist(err) {
return nil, nil
} else {
return nil, err
}
// Check presence of DAX-configured regions
devices, err = ioutil.ReadDir(source.SysfsDir.Path("bus/nd/devices"))
if err == nil {
for _, d := range devices {
if strings.HasPrefix(d.Name(), "dax") {
features["dax"] = true
}
}
} else {
log.Printf("WARNING: failed to detect NVDIMM configuration: %s", err)
}
return features, nil
}