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[#59] Add node states #60

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merged 2 commits into from
Mar 3, 2024
Merged

[#59] Add node states #60

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6bb9e32
[#59] Add node states
maypok86 Mar 2, 2024
03b6bf0
[#59] Fix non-deterministic node insertion
maypok86 Mar 3, 2024
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25 changes: 23 additions & 2 deletions cmd/generator/main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -134,8 +134,10 @@ func newGenerator(nodeType string) *generator {
func (g *generator) printImports() {
g.p("import (")
g.in()
g.p("\"sync/atomic\"")
g.p("\"unsafe\"")
if g.features[expiration] {
g.p("")
g.p("\"github.com/maypok86/otter/internal/unixtime\"")
}
g.out()
Expand Down Expand Up @@ -178,6 +180,7 @@ func (g *generator) printStruct() {
g.p("cost uint32")
}

g.p("state uint32")
g.p("frequency uint8")
g.p("queueType uint8")
g.out()
Expand All @@ -199,6 +202,7 @@ func (g *generator) printConstructors() {
if g.features[cost] {
g.p("cost: cost,")
}
g.p("state: aliveState,")
g.out()
g.p("}")
g.out()
Expand Down Expand Up @@ -365,6 +369,14 @@ func (g *generator) printFunctions() {
g.p("}")

const otherFunctions = `
func (n *%s[K, V]) IsAlive() bool {
return atomic.LoadUint32(&n.state) == aliveState
}

func (n *%s[K, V]) Die() {
atomic.StoreUint32(&n.state, deadState)
}

func (n *%s[K, V]) Frequency() uint8 {
return n.frequency
}
Expand Down Expand Up @@ -460,6 +472,11 @@ const (
maxFrequency uint8 = 3
)

const (
aliveState uint32 = iota
deadState
)

// Node is a cache entry.
type Node[K comparable, V any] interface {
// Key returns the key.
Expand Down Expand Up @@ -490,6 +507,10 @@ type Node[K comparable, V any] interface {
Expiration() uint32
// Cost returns the cost of the node.
Cost() uint32
// IsAlive returns true if the entry is available in the hash-table.
IsAlive() bool
// Die sets the node to the dead state.
Die()
// Frequency returns the frequency of the node.
Frequency() uint8
// IncrementFrequency increments the frequency of the node.
Expand Down Expand Up @@ -522,11 +543,11 @@ func Equals[K comparable, V any](a, b Node[K, V]) bool {

type Config struct {
WithExpiration bool
WithCost bool
WithCost bool
}

type Manager[K comparable, V any] struct {
create func(key K, value V, expiration, cost uint32) Node[K, V]
create func(key K, value V, expiration, cost uint32) Node[K, V]
fromPointer func(ptr unsafe.Pointer) Node[K, V]
}

Expand Down
95 changes: 58 additions & 37 deletions internal/core/cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@ import (
"github.com/maypok86/otter/internal/queue"
"github.com/maypok86/otter/internal/s3fifo"
"github.com/maypok86/otter/internal/stats"
"github.com/maypok86/otter/internal/task"
"github.com/maypok86/otter/internal/unixtime"
"github.com/maypok86/otter/internal/xmath"
"github.com/maypok86/otter/internal/xruntime"
Expand Down Expand Up @@ -68,7 +67,7 @@ type Cache[K comparable, V any] struct {
expirePolicy expirePolicy[K, V]
stats *stats.Stats
readBuffers []*lossy.Buffer[K, V]
writeBuffer *queue.MPSC[task.WriteTask[K, V]]
writeBuffer *queue.MPSC[task[K, V]]
evictionMutex sync.Mutex
closeOnce sync.Once
doneClear chan struct{}
Expand Down Expand Up @@ -120,7 +119,7 @@ func NewCache[K comparable, V any](c Config[K, V]) *Cache[K, V] {
policy: s3fifo.NewPolicy[K, V](uint32(c.Capacity)),
expirePolicy: expPolicy,
readBuffers: readBuffers,
writeBuffer: queue.NewMPSC[task.WriteTask[K, V]](writeBufferCapacity),
writeBuffer: queue.NewMPSC[task[K, V]](writeBufferCapacity),
doneClear: make(chan struct{}),
mask: uint32(readBuffersCount - 1),
costFunc: c.CostFunc,
Expand Down Expand Up @@ -159,13 +158,13 @@ func (c *Cache[K, V]) Has(key K) bool {
// Get returns the value associated with the key in this cache.
func (c *Cache[K, V]) Get(key K) (V, bool) {
got, ok := c.hashmap.Get(key)
if !ok {
if !ok || !got.IsAlive() {
c.stats.IncMisses()
return zeroValue[V](), false
}

if got.IsExpired() {
c.writeBuffer.Insert(task.NewDeleteTask(got))
c.writeBuffer.Insert(newDeleteTask(got))
c.stats.IncMisses()
return zeroValue[V](), false
}
Expand Down Expand Up @@ -240,7 +239,7 @@ func (c *Cache[K, V]) set(key K, value V, expiration uint32, onlyIfAbsent bool)
res := c.hashmap.SetIfAbsent(n)
if res == nil {
// insert
c.writeBuffer.Insert(task.NewAddTask(n))
c.writeBuffer.Insert(newAddTask(n))
return true
}
return false
Expand All @@ -249,34 +248,36 @@ func (c *Cache[K, V]) set(key K, value V, expiration uint32, onlyIfAbsent bool)
evicted := c.hashmap.Set(n)
if evicted != nil {
// update
c.writeBuffer.Insert(task.NewUpdateTask(n, evicted))
evicted.Die()
c.writeBuffer.Insert(newUpdateTask(n, evicted))
} else {
// insert
c.writeBuffer.Insert(task.NewAddTask(n))
c.writeBuffer.Insert(newAddTask(n))
}

return true
}

// Delete removes the association for this key from the cache.
func (c *Cache[K, V]) Delete(key K) {
deleted := c.hashmap.Delete(key)
if deleted != nil {
c.writeBuffer.Insert(task.NewDeleteTask(deleted))
}
c.afterDelete(c.hashmap.Delete(key))
}

func (c *Cache[K, V]) deleteNode(n node.Node[K, V]) {
deleted := c.hashmap.DeleteNode(n)
c.afterDelete(c.hashmap.DeleteNode(n))
}

func (c *Cache[K, V]) afterDelete(deleted node.Node[K, V]) {
if deleted != nil {
c.writeBuffer.Insert(task.NewDeleteTask(deleted))
deleted.Die()
c.writeBuffer.Insert(newDeleteTask(deleted))
}
}

// DeleteByFunc removes the association for this key from the cache when the given function returns true.
func (c *Cache[K, V]) DeleteByFunc(f func(key K, value V) bool) {
c.hashmap.Range(func(n node.Node[K, V]) bool {
if n.IsExpired() {
if !n.IsAlive() || n.IsExpired() {
return true
}

Expand All @@ -289,7 +290,8 @@ func (c *Cache[K, V]) DeleteByFunc(f func(key K, value V) bool) {
}

func (c *Cache[K, V]) cleanup() {
expired := make([]node.Node[K, V], 0, 128)
bufferCapacity := 64
expired := make([]node.Node[K, V], 0, bufferCapacity)
for {
time.Sleep(time.Second)

Expand All @@ -298,41 +300,47 @@ func (c *Cache[K, V]) cleanup() {
return
}

e := c.expirePolicy.RemoveExpired(expired)
c.policy.Delete(e)
expired = c.expirePolicy.RemoveExpired(expired)
for _, n := range expired {
c.policy.Delete(n)
}

c.evictionMutex.Unlock()

for _, n := range e {
for _, n := range expired {
c.hashmap.DeleteNode(n)
n.Die()
}

expired = clearBuffer(expired)
if cap(expired) > 3*bufferCapacity {
expired = make([]node.Node[K, V], 0, bufferCapacity)
}
}
}

func (c *Cache[K, V]) process() {
bufferCapacity := 64
buffer := make([]task.WriteTask[K, V], 0, bufferCapacity)
buffer := make([]task[K, V], 0, bufferCapacity)
deleted := make([]node.Node[K, V], 0, bufferCapacity)
i := 0
for {
t := c.writeBuffer.Remove()

if t.IsClear() || t.IsClose() {
if t.isClear() || t.isClose() {
buffer = clearBuffer(buffer)
c.writeBuffer.Clear()

c.evictionMutex.Lock()
c.policy.Clear()
c.expirePolicy.Clear()
if t.IsClose() {
if t.isClose() {
c.isClosed = true
}
c.evictionMutex.Unlock()

c.doneClear <- struct{}{}
if t.IsClose() {
if t.isClose() {
break
}
continue
Expand All @@ -346,30 +354,43 @@ func (c *Cache[K, V]) process() {
c.evictionMutex.Lock()

for _, t := range buffer {
n := t.node()
switch {
case t.IsDelete():
c.expirePolicy.Delete(t.Node())
case t.IsAdd():
c.expirePolicy.Add(t.Node())
case t.IsUpdate():
c.expirePolicy.Delete(t.OldNode())
c.expirePolicy.Add(t.Node())
case t.isDelete():
c.expirePolicy.Delete(n)
c.policy.Delete(n)
case t.isAdd():
if n.IsAlive() {
c.expirePolicy.Add(n)
deleted = c.policy.Add(deleted, n)
}
case t.isUpdate():
oldNode := t.oldNode()
c.expirePolicy.Delete(oldNode)
c.policy.Delete(oldNode)
if n.IsAlive() {
c.expirePolicy.Add(n)
deleted = c.policy.Add(deleted, n)
}
}
}

d := c.policy.Write(deleted, buffer)
for _, n := range d {
for _, n := range deleted {
c.expirePolicy.Delete(n)
}

c.evictionMutex.Unlock()

for _, n := range d {
for _, n := range deleted {
c.hashmap.DeleteNode(n)
n.Die()
}

buffer = clearBuffer(buffer)
deleted = clearBuffer(deleted)
if cap(deleted) > 3*bufferCapacity {
deleted = make([]node.Node[K, V], 0, bufferCapacity)
}
}
}
}
Expand All @@ -379,7 +400,7 @@ func (c *Cache[K, V]) process() {
// Iteration stops early when the given function returns false.
func (c *Cache[K, V]) Range(f func(key K, value V) bool) {
c.hashmap.Range(func(n node.Node[K, V]) bool {
if n.IsExpired() {
if !n.IsAlive() || n.IsExpired() {
return true
}

Expand All @@ -391,10 +412,10 @@ func (c *Cache[K, V]) Range(f func(key K, value V) bool) {
//
// NOTE: this operation must be performed when no requests are made to the cache otherwise the behavior is undefined.
func (c *Cache[K, V]) Clear() {
c.clear(task.NewClearTask[K, V]())
c.clear(newClearTask[K, V]())
}

func (c *Cache[K, V]) clear(t task.WriteTask[K, V]) {
func (c *Cache[K, V]) clear(t task[K, V]) {
c.hashmap.Clear()
for i := 0; i < len(c.readBuffers); i++ {
c.readBuffers[i].Clear()
Expand All @@ -411,7 +432,7 @@ func (c *Cache[K, V]) clear(t task.WriteTask[K, V]) {
// NOTE: this operation must be performed when no requests are made to the cache otherwise the behavior is undefined.
func (c *Cache[K, V]) Close() {
c.closeOnce.Do(func() {
c.clear(task.NewCloseTask[K, V]())
c.clear(newCloseTask[K, V]())
if c.withExpiration {
unixtime.Stop()
}
Expand Down
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