// NewARC creates an ARC of the given size
func NewARC(size int) (*ARCCache, error) {
// Create the sub LRUs
b1, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
b2, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
t1, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
t2, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
// Initialize the ARC
c := &ARCCache{
size: size,
p: 0,
t1: t1,
b1: b1,
t2: t2,
b2: b2,
}
return c, nil
}
// writeNode returns a node to be modified, if the current
// node as already been modified during the course of
// the transaction, it is used in-place.
func (t *Txn) writeNode(n *Node) *Node {
// Ensure the modified set exists
if t.modified == nil {
lru, err := simplelru.NewLRU(defaultModifiedCache, nil)
if err != nil {
panic(err)
}
t.modified = lru
}
// If this node has already been modified, we can
// continue to use it during this transaction.
if _, ok := t.modified.Get(n); ok {
return n
}
// Copy the existing node
nc := new(Node)
if n.prefix != nil {
nc.prefix = make([]byte, len(n.prefix))
copy(nc.prefix, n.prefix)
}
if n.leaf != nil {
nc.leaf = new(leafNode)
*nc.leaf = *n.leaf
}
if len(n.edges) != 0 {
nc.edges = make([]edge, len(n.edges))
copy(nc.edges, n.edges)
}
// Mark this node as modified
t.modified.Add(n, nil)
return nc
}
func New(size int) (*Cache, error) {
list, err := lru.NewLRU(size, clean)
if err != nil {
return nil, err
}
runtime.SetFinalizer(list, (*lru.LRU).Purge)
return &Cache{list: list}, nil
}
// NewWithEvict constructs a fixed size cache with the given eviction
// callback.
func NewWithEvict(size int, onEvicted func(key interface{}, value interface{})) (*Cache, error) {
lru, err := simplelru.NewLRU(size, simplelru.EvictCallback(onEvicted))
if err != nil {
return nil, err
}
c := &Cache{
lru: lru,
}
return c, nil
}
// New2QParams creates a new TwoQueueCache using the provided
// parameter values.
func New2QParams(size int, recentRatio float64, ghostRatio float64) (*TwoQueueCache, error) {
if size <= 0 {
return nil, fmt.Errorf("invalid size")
}
if recentRatio < 0.0 || recentRatio > 1.0 {
return nil, fmt.Errorf("invalid recent ratio")
}
if ghostRatio < 0.0 || ghostRatio > 1.0 {
return nil, fmt.Errorf("invalid ghost ratio")
}
// Determine the sub-sizes
recentSize := int(float64(size) * recentRatio)
evictSize := int(float64(size) * ghostRatio)
// Allocate the LRUs
recent, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
frequent, err := simplelru.NewLRU(size, nil)
if err != nil {
return nil, err
}
recentEvict, err := simplelru.NewLRU(evictSize, nil)
if err != nil {
return nil, err
}
// Initialize the cache
c := &TwoQueueCache{
size: size,
recentSize: recentSize,
recent: recent,
frequent: frequent,
recentEvict: recentEvict,
}
return c, nil
}
// NewCache creates a new cache
func NewCache(name string, maxEntries int, maxSizeMB int, maxAge time.Duration) *Cache {
c := &Cache{
name: name,
maxAge: maxAge,
maxSizeBytes: maxSizeMB * 1024 * 1024,
}
var err error
c.lruBackend, err = simplelru.NewLRU(maxEntries, simplelru.EvictCallback(c.onEvicted))
if err != nil {
panic(err)
}
return c
}
// writeNode returns a node to be modified, if the current node has already been
// modified during the course of the transaction, it is used in-place. Set
// forLeafUpdate to true if you are getting a write node to update the leaf,
// which will set leaf mutation tracking appropriately as well.
func (t *Txn) writeNode(n *Node, forLeafUpdate bool) *Node {
// Ensure the writable set exists.
if t.writable == nil {
lru, err := simplelru.NewLRU(defaultModifiedCache, nil)
if err != nil {
panic(err)
}
t.writable = lru
}
// If this node has already been modified, we can continue to use it
// during this transaction. If a node gets kicked out of cache then we
// *may* notify for its mutation if we end up copying the node again,
// but we don't make any guarantees about notifying for intermediate
// mutations that were never exposed outside of a transaction.
if _, ok := t.writable.Get(n); ok {
return n
}
// Mark this node as being mutated.
if t.trackMutate {
t.trackChannel(&(n.mutateCh))
}
// Mark its leaf as being mutated, if appropriate.
if t.trackMutate && forLeafUpdate && n.leaf != nil {
t.trackChannel(&(n.leaf.mutateCh))
}
// Copy the existing node.
nc := &Node{
mutateCh: make(chan struct{}),
leaf: n.leaf,
}
if n.prefix != nil {
nc.prefix = make([]byte, len(n.prefix))
copy(nc.prefix, n.prefix)
}
if len(n.edges) != 0 {
nc.edges = make([]edge, len(n.edges))
copy(nc.edges, n.edges)
}
// Mark this node as writable.
t.writable.Add(nc, nil)
return nc
}
func (lg *Log) SetCacheSize(size int) {
lg.cache, _ = lru.NewLRU(size, nil)
}