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Move scheduling Heap in to scheduler.core.utils

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The Heap data structure is useful for our backoff system in addition to
scheduling queue. Move it to somewhere it can be consumed by both
systems and properly export needed names. Also adding unit tests
from client-go/tools/cache/heap.go.
This commit is contained in:
Gregory Haynes
2017-12-09 23:09:48 +00:00
parent 3b53ea5ea4
commit c821f2ed2f
5 changed files with 503 additions and 203 deletions
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204
pkg/scheduler/internal/queue/scheduling_queue.go
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@@ -27,7 +27,6 @@ limitations under the License.
package queue
import (
"container/heap"
"fmt"
"reflect"
"sync"
@@ -184,7 +183,7 @@ type PriorityQueue struct {
// activeQ is heap structure that scheduler actively looks at to find pods to
// schedule. Head of heap is the highest priority pod.
activeQ *Heap
activeQ *util.Heap
// unschedulableQ holds pods that have been tried and determined unschedulable.
unschedulableQ *UnschedulablePodsMap
// nominatedPods is a map keyed by a node name and the value is a list of
@@ -230,7 +229,7 @@ func activeQComp(pod1, pod2 interface{}) bool {
// NewPriorityQueue creates a PriorityQueue object.
func NewPriorityQueue() *PriorityQueue {
pq := &PriorityQueue{
activeQ: newHeap(cache.MetaNamespaceKeyFunc, activeQComp),
activeQ: util.NewHeap(cache.MetaNamespaceKeyFunc, activeQComp),
unschedulableQ: newUnschedulablePodsMap(),
nominatedPods: map[string][]*v1.Pod{},
}
@@ -355,7 +354,7 @@ func (p *PriorityQueue) AddUnschedulableIfNotPresent(pod *v1.Pod) error {
func (p *PriorityQueue) Pop() (*v1.Pod, error) {
p.lock.Lock()
defer p.lock.Unlock()
for len(p.activeQ.data.queue) == 0 {
for p.activeQ.Len() == 0 {
// When the queue is empty, invocation of Pop() is blocked until new item is enqueued.
// When Close() is called, the p.closed is set and the condition is broadcast,
// which causes this loop to continue and return from the Pop().
@@ -591,200 +590,3 @@ func newUnschedulablePodsMap() *UnschedulablePodsMap {
keyFunc: util.GetPodFullName,
}
}
// Below is the implementation of the a heap. The logic is pretty much the same
// as cache.heap, however, this heap does not perform synchronization. It leaves
// synchronization to the SchedulingQueue.
// LessFunc is a function type to compare two objects.
type LessFunc func(interface{}, interface{}) bool
// KeyFunc is a function type to get the key from an object.
type KeyFunc func(obj interface{}) (string, error)
type heapItem struct {
obj interface{} // The object which is stored in the heap.
index int // The index of the object's key in the Heap.queue.
}
type itemKeyValue struct {
key string
obj interface{}
}
// heapData is an internal struct that implements the standard heap interface
// and keeps the data stored in the heap.
type heapData struct {
// items is a map from key of the objects to the objects and their index.
// We depend on the property that items in the map are in the queue and vice versa.
items map[string]*heapItem
// queue implements a heap data structure and keeps the order of elements
// according to the heap invariant. The queue keeps the keys of objects stored
// in "items".
queue []string
// keyFunc is used to make the key used for queued item insertion and retrieval, and
// should be deterministic.
keyFunc KeyFunc
// lessFunc is used to compare two objects in the heap.
lessFunc LessFunc
}
var (
_ = heap.Interface(&heapData{}) // heapData is a standard heap
)
// Less compares two objects and returns true if the first one should go
// in front of the second one in the heap.
func (h *heapData) Less(i, j int) bool {
if i > len(h.queue) || j > len(h.queue) {
return false
}
itemi, ok := h.items[h.queue[i]]
if !ok {
return false
}
itemj, ok := h.items[h.queue[j]]
if !ok {
return false
}
return h.lessFunc(itemi.obj, itemj.obj)
}
// Len returns the number of items in the Heap.
func (h *heapData) Len() int { return len(h.queue) }
// Swap implements swapping of two elements in the heap. This is a part of standard
// heap interface and should never be called directly.
func (h *heapData) Swap(i, j int) {
h.queue[i], h.queue[j] = h.queue[j], h.queue[i]
item := h.items[h.queue[i]]
item.index = i
item = h.items[h.queue[j]]
item.index = j
}
// Push is supposed to be called by heap.Push only.
func (h *heapData) Push(kv interface{}) {
keyValue := kv.(*itemKeyValue)
n := len(h.queue)
h.items[keyValue.key] = &heapItem{keyValue.obj, n}
h.queue = append(h.queue, keyValue.key)
}
// Pop is supposed to be called by heap.Pop only.
func (h *heapData) Pop() interface{} {
key := h.queue[len(h.queue)-1]
h.queue = h.queue[0 : len(h.queue)-1]
item, ok := h.items[key]
if !ok {
// This is an error
return nil
}
delete(h.items, key)
return item.obj
}
// Heap is a producer/consumer queue that implements a heap data structure.
// It can be used to implement priority queues and similar data structures.
type Heap struct {
// data stores objects and has a queue that keeps their ordering according
// to the heap invariant.
data *heapData
}
// Add inserts an item, and puts it in the queue. The item is updated if it
// already exists.
func (h *Heap) Add(obj interface{}) error {
key, err := h.data.keyFunc(obj)
if err != nil {
return cache.KeyError{Obj: obj, Err: err}
}
if _, exists := h.data.items[key]; exists {
h.data.items[key].obj = obj
heap.Fix(h.data, h.data.items[key].index)
} else {
heap.Push(h.data, &itemKeyValue{key, obj})
}
return nil
}
// AddIfNotPresent inserts an item, and puts it in the queue. If an item with
// the key is present in the map, no changes is made to the item.
func (h *Heap) AddIfNotPresent(obj interface{}) error {
key, err := h.data.keyFunc(obj)
if err != nil {
return cache.KeyError{Obj: obj, Err: err}
}
if _, exists := h.data.items[key]; !exists {
heap.Push(h.data, &itemKeyValue{key, obj})
}
return nil
}
// Update is the same as Add in this implementation. When the item does not
// exist, it is added.
func (h *Heap) Update(obj interface{}) error {
return h.Add(obj)
}
// Delete removes an item.
func (h *Heap) Delete(obj interface{}) error {
key, err := h.data.keyFunc(obj)
if err != nil {
return cache.KeyError{Obj: obj, Err: err}
}
if item, ok := h.data.items[key]; ok {
heap.Remove(h.data, item.index)
return nil
}
return fmt.Errorf("object not found")
}
// Pop returns the head of the heap.
func (h *Heap) Pop() (interface{}, error) {
obj := heap.Pop(h.data)
if obj != nil {
return obj, nil
}
return nil, fmt.Errorf("object was removed from heap data")
}
// Get returns the requested item, or sets exists=false.
func (h *Heap) Get(obj interface{}) (interface{}, bool, error) {
key, err := h.data.keyFunc(obj)
if err != nil {
return nil, false, cache.KeyError{Obj: obj, Err: err}
}
return h.GetByKey(key)
}
// GetByKey returns the requested item, or sets exists=false.
func (h *Heap) GetByKey(key string) (interface{}, bool, error) {
item, exists := h.data.items[key]
if !exists {
return nil, false, nil
}
return item.obj, true, nil
}
// List returns a list of all the items.
func (h *Heap) List() []interface{} {
list := make([]interface{}, 0, len(h.data.items))
for _, item := range h.data.items {
list = append(list, item.obj)
}
return list
}
// newHeap returns a Heap which can be used to queue up items to process.
func newHeap(keyFn KeyFunc, lessFn LessFunc) *Heap {
return &Heap{
data: &heapData{
items: map[string]*heapItem{},
queue: []string{},
keyFunc: keyFn,
lessFunc: lessFn,
},
}
}