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package chunk_cache
import (
"sync"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/chrislusf/seaweedfs/weed/storage/needle"
)
const (
memCacheSizeLimit = 1024 * 1024
onDiskCacheSizeLimit0 = memCacheSizeLimit
onDiskCacheSizeLimit1 = 4 * memCacheSizeLimit
)
// a global cache for recently accessed file chunks
type ChunkCache struct {
memCache *ChunkCacheInMemory
diskCaches []*OnDiskCacheLayer
sync.RWMutex
}
func NewChunkCache(maxEntries int64, dir string, diskSizeMB int64) *ChunkCache {
c := &ChunkCache{
memCache: NewChunkCacheInMemory(maxEntries),
}
c.diskCaches = make([]*OnDiskCacheLayer, 3)
c.diskCaches[0] = NewOnDiskCacheLayer(dir, "c0_1", diskSizeMB/4, 4)
c.diskCaches[1] = NewOnDiskCacheLayer(dir, "c1_4", diskSizeMB/4, 4)
c.diskCaches[2] = NewOnDiskCacheLayer(dir, "cache", diskSizeMB/2, 4)
return c
}
func (c *ChunkCache) GetChunk(fileId string, chunkSize uint64) (data []byte) {
if c == nil {
return
}
c.RLock()
defer c.RUnlock()
return c.doGetChunk(fileId, chunkSize)
}
func (c *ChunkCache) doGetChunk(fileId string, chunkSize uint64) (data []byte) {
if chunkSize < memCacheSizeLimit {
data = c.memCache.GetChunk(fileId)
if len(data) >= int(chunkSize) {
return data
}
}
fid, err := needle.ParseFileIdFromString(fileId)
if err != nil {
glog.Errorf("failed to parse file id %s", fileId)
return nil
}
if chunkSize < onDiskCacheSizeLimit0 {
data = c.diskCaches[0].getChunk(fid.Key)
if len(data) >= int(chunkSize) {
return data
}
}
if chunkSize < onDiskCacheSizeLimit1 {
data = c.diskCaches[1].getChunk(fid.Key)
if len(data) >= int(chunkSize) {
return data
}
}
{
data = c.diskCaches[2].getChunk(fid.Key)
if len(data) >= int(chunkSize) {
return data
}
}
return nil
}
func (c *ChunkCache) SetChunk(fileId string, data []byte) {
if c == nil {
return
}
c.Lock()
defer c.Unlock()
glog.V(4).Infof("SetChunk %s size %d\n", fileId, len(data))
c.doSetChunk(fileId, data)
}
func (c *ChunkCache) doSetChunk(fileId string, data []byte) {
if len(data) < memCacheSizeLimit {
c.memCache.SetChunk(fileId, data)
}
fid, err := needle.ParseFileIdFromString(fileId)
if err != nil {
glog.Errorf("failed to parse file id %s", fileId)
return
}
if len(data) < onDiskCacheSizeLimit0 {
c.diskCaches[0].setChunk(fid.Key, data)
} else if len(data) < onDiskCacheSizeLimit1 {
c.diskCaches[1].setChunk(fid.Key, data)
} else {
c.diskCaches[2].setChunk(fid.Key, data)
}
}
func (c *ChunkCache) Shutdown() {
if c == nil {
return
}
c.Lock()
defer c.Unlock()
for _, diskCache := range c.diskCaches {
diskCache.shutdown()
}
}
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