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144 lines
3.2 KiB
144 lines
3.2 KiB
package chunk_cache
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import (
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"errors"
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"sync"
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"github.com/seaweedfs/seaweedfs/weed/glog"
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"github.com/seaweedfs/seaweedfs/weed/storage/needle"
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)
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var ErrorOutOfBounds = errors.New("attempt to read out of bounds")
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type ChunkCache interface {
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ReadChunkAt(data []byte, fileId string, offset uint64) (n int, err error)
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SetChunk(fileId string, data []byte)
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}
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// a global cache for recently accessed file chunks
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type TieredChunkCache struct {
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memCache *ChunkCacheInMemory
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diskCaches []*OnDiskCacheLayer
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sync.RWMutex
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onDiskCacheSizeLimit0 uint64
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onDiskCacheSizeLimit1 uint64
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onDiskCacheSizeLimit2 uint64
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}
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var _ ChunkCache = &TieredChunkCache{}
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func NewTieredChunkCache(maxEntries int64, dir string, diskSizeInUnit int64, unitSize int64) *TieredChunkCache {
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c := &TieredChunkCache{
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memCache: NewChunkCacheInMemory(maxEntries),
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}
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c.diskCaches = make([]*OnDiskCacheLayer, 3)
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c.onDiskCacheSizeLimit0 = uint64(unitSize)
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c.onDiskCacheSizeLimit1 = 4 * c.onDiskCacheSizeLimit0
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c.onDiskCacheSizeLimit2 = 2 * c.onDiskCacheSizeLimit1
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c.diskCaches[0] = NewOnDiskCacheLayer(dir, "c0_2", diskSizeInUnit*unitSize/8, 2)
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c.diskCaches[1] = NewOnDiskCacheLayer(dir, "c1_3", diskSizeInUnit*unitSize/4+diskSizeInUnit*unitSize/8, 3)
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c.diskCaches[2] = NewOnDiskCacheLayer(dir, "c2_2", diskSizeInUnit*unitSize/2, 2)
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return c
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}
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func (c *TieredChunkCache) ReadChunkAt(data []byte, fileId string, offset uint64) (n int, err error) {
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if c == nil {
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return 0, nil
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}
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c.RLock()
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defer c.RUnlock()
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minSize := offset + uint64(len(data))
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if minSize <= c.onDiskCacheSizeLimit0 {
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n, err = c.memCache.readChunkAt(data, fileId, offset)
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if err != nil {
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glog.Errorf("failed to read from memcache: %s", err)
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}
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if n >= int(minSize) {
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return n, nil
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}
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}
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fid, err := needle.ParseFileIdFromString(fileId)
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if err != nil {
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glog.Errorf("failed to parse file id %s", fileId)
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return n, nil
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}
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if minSize <= c.onDiskCacheSizeLimit0 {
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n, err = c.diskCaches[0].readChunkAt(data, fid.Key, offset)
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if n >= int(minSize) {
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return
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}
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}
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if minSize <= c.onDiskCacheSizeLimit1 {
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n, err = c.diskCaches[1].readChunkAt(data, fid.Key, offset)
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if n >= int(minSize) {
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return
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}
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}
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{
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n, err = c.diskCaches[2].readChunkAt(data, fid.Key, offset)
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if n >= int(minSize) {
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return
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}
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}
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return 0, nil
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}
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func (c *TieredChunkCache) SetChunk(fileId string, data []byte) {
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if c == nil {
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return
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}
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c.Lock()
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defer c.Unlock()
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glog.V(4).Infof("SetChunk %s size %d\n", fileId, len(data))
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c.doSetChunk(fileId, data)
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}
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func (c *TieredChunkCache) doSetChunk(fileId string, data []byte) {
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if len(data) <= int(c.onDiskCacheSizeLimit0) {
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c.memCache.SetChunk(fileId, data)
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}
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fid, err := needle.ParseFileIdFromString(fileId)
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if err != nil {
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glog.Errorf("failed to parse file id %s", fileId)
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return
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}
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if len(data) <= int(c.onDiskCacheSizeLimit0) {
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c.diskCaches[0].setChunk(fid.Key, data)
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} else if len(data) <= int(c.onDiskCacheSizeLimit1) {
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c.diskCaches[1].setChunk(fid.Key, data)
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} else {
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c.diskCaches[2].setChunk(fid.Key, data)
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}
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}
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func (c *TieredChunkCache) Shutdown() {
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if c == nil {
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return
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}
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c.Lock()
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defer c.Unlock()
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for _, diskCache := range c.diskCaches {
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diskCache.shutdown()
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}
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}
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func min(x, y int) int {
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if x < y {
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return x
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}
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return y
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}
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