68bb0935bd
Device Plugins that wish to leverage the Topology Manager can send back a populated
TopologyInfo struct as part of the device registration, along with the device IDs
and the health of the device. TopologyInfo is converted to TopologyHints and
used by TopologyManager to find the optimal/desired resource allocation for a Pod.
If a plugin sends an empty but non-nil instance of TopologyInfo for a resource,
devicemanager passes it on as an empty instance of TopologyHint which is
currently interpreted as "Hint Provider has no possible NUMA affinities
for resource" which further means that pods requesting that resource will fail.
To not block device resources that pass TopologyInfo{Nodes:[]*NUMANode{}} from being
used, interprete that as nil set of hints and not a []TopologyHint{}.
Signed-off-by: Mikko Ylinen <mikko.ylinen@intel.com>
300 lines
11 KiB
Go
300 lines
11 KiB
Go
/*
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Copyright 2019 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 devicemanager
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import (
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"k8s.io/api/core/v1"
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"k8s.io/apimachinery/pkg/util/sets"
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"k8s.io/klog/v2"
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pluginapi "k8s.io/kubelet/pkg/apis/deviceplugin/v1beta1"
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"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager"
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"k8s.io/kubernetes/pkg/kubelet/cm/topologymanager/bitmask"
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)
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// GetTopologyHints implements the TopologyManager HintProvider Interface which
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// ensures the Device Manager is consulted when Topology Aware Hints for each
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// container are created.
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func (m *ManagerImpl) GetTopologyHints(pod *v1.Pod, container *v1.Container) map[string][]topologymanager.TopologyHint {
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// The pod is during the admission phase. We need to save the pod to avoid it
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// being cleaned before the admission ended
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m.setPodPendingAdmission(pod)
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// Garbage collect any stranded device resources before providing TopologyHints
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m.UpdateAllocatedDevices()
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// Loop through all device resources and generate TopologyHints for them..
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deviceHints := make(map[string][]topologymanager.TopologyHint)
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for resourceObj, requestedObj := range container.Resources.Limits {
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resource := string(resourceObj)
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requested := int(requestedObj.Value())
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// Only consider resources associated with a device plugin.
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if m.isDevicePluginResource(resource) {
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// Only consider devices that actually container topology information.
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if aligned := m.deviceHasTopologyAlignment(resource); !aligned {
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klog.InfoS("Resource does not have a topology preference", "resource", resource)
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deviceHints[resource] = nil
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continue
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}
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// Short circuit to regenerate the same hints if there are already
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// devices allocated to the Container. This might happen after a
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// kubelet restart, for example.
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allocated := m.podDevices.containerDevices(string(pod.UID), container.Name, resource)
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if allocated.Len() > 0 {
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if allocated.Len() != requested {
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klog.ErrorS(nil, "Resource already allocated to pod with different number than request", "resource", resource, "pod", klog.KObj(pod), "containerName", container.Name, "request", requested, "allocated", allocated.Len())
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deviceHints[resource] = []topologymanager.TopologyHint{}
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continue
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}
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klog.InfoS("Regenerating TopologyHints for resource already allocated to pod", "resource", resource, "pod", klog.KObj(pod), "containerName", container.Name)
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deviceHints[resource] = m.generateDeviceTopologyHints(resource, allocated, sets.String{}, requested)
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continue
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}
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// Get the list of available devices, for which TopologyHints should be generated.
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available := m.getAvailableDevices(resource)
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reusable := m.devicesToReuse[string(pod.UID)][resource]
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if available.Union(reusable).Len() < requested {
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klog.ErrorS(nil, "Unable to generate topology hints: requested number of devices unavailable", "resource", resource, "request", requested, "available", available.Union(reusable).Len())
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deviceHints[resource] = []topologymanager.TopologyHint{}
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continue
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}
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// Generate TopologyHints for this resource given the current
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// request size and the list of available devices.
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deviceHints[resource] = m.generateDeviceTopologyHints(resource, available, reusable, requested)
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}
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}
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return deviceHints
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}
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// GetPodTopologyHints implements the topologymanager.HintProvider Interface which
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// ensures the Device Manager is consulted when Topology Aware Hints for Pod are created.
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func (m *ManagerImpl) GetPodTopologyHints(pod *v1.Pod) map[string][]topologymanager.TopologyHint {
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// The pod is during the admission phase. We need to save the pod to avoid it
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// being cleaned before the admission ended
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m.setPodPendingAdmission(pod)
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// Garbage collect any stranded device resources before providing TopologyHints
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m.UpdateAllocatedDevices()
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deviceHints := make(map[string][]topologymanager.TopologyHint)
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accumulatedResourceRequests := m.getPodDeviceRequest(pod)
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for resource, requested := range accumulatedResourceRequests {
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// Only consider devices that actually contain topology information.
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if aligned := m.deviceHasTopologyAlignment(resource); !aligned {
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klog.InfoS("Resource does not have a topology preference", "resource", resource)
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deviceHints[resource] = nil
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continue
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}
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// Short circuit to regenerate the same hints if there are already
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// devices allocated to the Pod. This might happen after a
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// kubelet restart, for example.
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allocated := m.podDevices.podDevices(string(pod.UID), resource)
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if allocated.Len() > 0 {
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if allocated.Len() != requested {
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klog.ErrorS(nil, "Resource already allocated to pod with different number than request", "resource", resource, "pod", klog.KObj(pod), "request", requested, "allocated", allocated.Len())
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deviceHints[resource] = []topologymanager.TopologyHint{}
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continue
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}
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klog.InfoS("Regenerating TopologyHints for resource already allocated to pod", "resource", resource, "pod", klog.KObj(pod))
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deviceHints[resource] = m.generateDeviceTopologyHints(resource, allocated, sets.String{}, requested)
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continue
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}
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// Get the list of available devices, for which TopologyHints should be generated.
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available := m.getAvailableDevices(resource)
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if available.Len() < requested {
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klog.ErrorS(nil, "Unable to generate topology hints: requested number of devices unavailable", "resource", resource, "request", requested, "available", available.Len())
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deviceHints[resource] = []topologymanager.TopologyHint{}
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continue
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}
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// Generate TopologyHints for this resource given the current
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// request size and the list of available devices.
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deviceHints[resource] = m.generateDeviceTopologyHints(resource, available, sets.String{}, requested)
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}
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return deviceHints
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}
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func (m *ManagerImpl) deviceHasTopologyAlignment(resource string) bool {
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// If any device has Topology NUMANodes available, we assume they care about alignment.
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for _, device := range m.allDevices[resource] {
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if device.Topology != nil && len(device.Topology.Nodes) > 0 {
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return true
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}
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}
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return false
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}
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func (m *ManagerImpl) getAvailableDevices(resource string) sets.String {
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// Strip all devices in use from the list of healthy ones.
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return m.healthyDevices[resource].Difference(m.allocatedDevices[resource])
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}
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func (m *ManagerImpl) generateDeviceTopologyHints(resource string, available sets.String, reusable sets.String, request int) []topologymanager.TopologyHint {
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// Initialize minAffinitySize to include all NUMA Nodes
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minAffinitySize := len(m.numaNodes)
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// Iterate through all combinations of NUMA Nodes and build hints from them.
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hints := []topologymanager.TopologyHint{}
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bitmask.IterateBitMasks(m.numaNodes, func(mask bitmask.BitMask) {
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// First, update minAffinitySize for the current request size.
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devicesInMask := 0
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for _, device := range m.allDevices[resource] {
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if mask.AnySet(m.getNUMANodeIds(device.Topology)) {
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devicesInMask++
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}
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}
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if devicesInMask >= request && mask.Count() < minAffinitySize {
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minAffinitySize = mask.Count()
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}
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// Then check to see if all of the reusable devices are part of the bitmask.
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numMatching := 0
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for d := range reusable {
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// Skip the device if it doesn't specify any topology info.
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if m.allDevices[resource][d].Topology == nil {
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continue
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}
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// Otherwise disregard this mask if its NUMANode isn't part of it.
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if !mask.AnySet(m.getNUMANodeIds(m.allDevices[resource][d].Topology)) {
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return
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}
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numMatching++
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}
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// Finally, check to see if enough available devices remain on the
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// current NUMA node combination to satisfy the device request.
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for d := range available {
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if mask.AnySet(m.getNUMANodeIds(m.allDevices[resource][d].Topology)) {
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numMatching++
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}
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}
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// If they don't, then move onto the next combination.
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if numMatching < request {
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return
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}
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// Otherwise, create a new hint from the NUMA mask and add it to the
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// list of hints. We set all hint preferences to 'false' on the first
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// pass through.
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hints = append(hints, topologymanager.TopologyHint{
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NUMANodeAffinity: mask,
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Preferred: false,
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})
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})
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// Loop back through all hints and update the 'Preferred' field based on
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// counting the number of bits sets in the affinity mask and comparing it
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// to the minAffinity. Only those with an equal number of bits set will be
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// considered preferred.
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for i := range hints {
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if hints[i].NUMANodeAffinity.Count() == minAffinitySize {
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hints[i].Preferred = true
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}
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}
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return hints
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}
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func (m *ManagerImpl) getNUMANodeIds(topology *pluginapi.TopologyInfo) []int {
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if topology == nil {
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return nil
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}
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var ids []int
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for _, n := range topology.Nodes {
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ids = append(ids, int(n.ID))
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}
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return ids
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}
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func (m *ManagerImpl) getPodDeviceRequest(pod *v1.Pod) map[string]int {
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podResources := sets.NewString()
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// Find the max request of a given resource across all init containers
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initContainerRequests := make(map[string]int)
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for _, container := range pod.Spec.InitContainers {
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for resourceObj, requestedObj := range container.Resources.Limits {
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resource := string(resourceObj)
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requested := int(requestedObj.Value())
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if !m.isDevicePluginResource(resource) {
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continue
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}
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podResources.Insert(resource)
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if _, exists := initContainerRequests[resource]; !exists {
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initContainerRequests[resource] = requested
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continue
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}
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if requested > initContainerRequests[resource] {
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initContainerRequests[resource] = requested
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}
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}
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}
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// Compute the sum of requests across all app containers for a given resource
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appContainerRequests := make(map[string]int)
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for _, container := range pod.Spec.Containers {
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for resourceObj, requestedObj := range container.Resources.Limits {
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resource := string(resourceObj)
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requested := int(requestedObj.Value())
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if !m.isDevicePluginResource(resource) {
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continue
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}
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podResources.Insert(resource)
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appContainerRequests[resource] += requested
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}
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}
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// Calculate podRequests as the max of init and app container requests for a given resource
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podRequests := make(map[string]int)
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for resource := range podResources {
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_, initExists := initContainerRequests[resource]
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_, appExists := appContainerRequests[resource]
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if initExists && !appExists {
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podRequests[resource] = initContainerRequests[resource]
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continue
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}
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if !initExists && appExists {
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podRequests[resource] = appContainerRequests[resource]
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continue
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}
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if initContainerRequests[resource] > appContainerRequests[resource] {
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podRequests[resource] = initContainerRequests[resource]
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continue
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}
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podRequests[resource] = appContainerRequests[resource]
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}
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return podRequests
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}
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