mount: add on disk caching

weed/util/chunk_cache/chunk_cache.go

@@ -1,36 +1,115 @@
 package chunk_cache
 
 import (
-	"time"
+	"fmt"
+	"path"
+	"sort"
+	"sync"
 
-	"github.com/karlseguin/ccache"
+	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/storage"
+	"github.com/chrislusf/seaweedfs/weed/storage/needle"
 )
 
 // a global cache for recently accessed file chunks
 type ChunkCache struct {
-	cache *ccache.Cache
+	memCache   *ChunkCacheInMemory
+	diskCaches []*ChunkCacheVolume
+	sync.RWMutex
 }
 
-func NewChunkCache(maxEntries int64) *ChunkCache {
-	pruneCount := maxEntries >> 3
-	if pruneCount <= 0 {
-		pruneCount = 500
+func NewChunkCache(maxEntries int64, dir string, diskSizeMB int64, segmentCount int) *ChunkCache {
+	c := &ChunkCache{
+		memCache: NewChunkCacheInMemory(maxEntries),
 	}
-	return &ChunkCache{
-		cache: ccache.New(ccache.Configure().MaxSize(maxEntries).ItemsToPrune(uint32(pruneCount))),
+
+	volumeCount, volumeSize := int(diskSizeMB/30000), int64(30000)
+	if volumeCount < segmentCount {
+		volumeCount, volumeSize = segmentCount, diskSizeMB/int64(segmentCount)
 	}
+
+	for i := 0; i < volumeCount; i++ {
+		fileName := path.Join(dir, fmt.Sprintf("cache_%d", i))
+		diskCache, err := LoadOrCreateChunkCacheVolume(fileName, volumeSize*1024*1024)
+		if err != nil {
+			glog.Errorf("failed to add cache %s : %v", fileName, err)
+		} else {
+			c.diskCaches = append(c.diskCaches, diskCache)
+		}
+	}
+
+	// keep newest cache to the front
+	sort.Slice(c.diskCaches, func(i, j int) bool {
+		return c.diskCaches[i].lastModTime.After(c.diskCaches[j].lastModTime)
+	})
+
+	return c
 }
 
-func (c *ChunkCache) GetChunk(fileId string) []byte {
-	item := c.cache.Get(fileId)
-	if item == nil {
+func (c *ChunkCache) GetChunk(fileId string) (data []byte) {
+	c.RLock()
+	defer c.RUnlock()
+
+	if data = c.memCache.GetChunk(fileId); data != nil {
+		return data
+	}
+
+	fid, err := needle.ParseFileIdFromString(fileId)
+	if err != nil {
+		glog.Errorf("failed to parse file id %s", fileId)
 		return nil
 	}
-	data := item.Value().([]byte)
-	item.Extend(time.Hour)
-	return data
+	for _, diskCache := range c.diskCaches {
+		data, err = diskCache.GetNeedle(fid.Key)
+		if err == storage.ErrorNotFound {
+			continue
+		}
+		if err != nil {
+			glog.Errorf("failed to read cache file %s id %s", diskCache.fileName, fileId)
+			continue
+		}
+		if len(data) != 0 {
+			return
+		}
+	}
+	return nil
 }
 
 func (c *ChunkCache) SetChunk(fileId string, data []byte) {
-	c.cache.Set(fileId, data, time.Hour)
+	c.Lock()
+	defer c.Unlock()
+
+	c.memCache.SetChunk(fileId, data)
+
+	if len(c.diskCaches) == 0 {
+		return
+	}
+
+	if c.diskCaches[0].fileSize+int64(len(data)) > c.diskCaches[0].sizeLimit {
+		t, resetErr := c.diskCaches[len(c.diskCaches)-1].Reset()
+		if resetErr != nil {
+			glog.Errorf("failed to reset cache file %s", c.diskCaches[len(c.diskCaches)-1].fileName)
+			return
+		}
+		for i := len(c.diskCaches) - 1; i > 0; i-- {
+			c.diskCaches[i] = c.diskCaches[i-1]
+		}
+		c.diskCaches[0] = t
+	}
+
+	fid, err := needle.ParseFileIdFromString(fileId)
+	if err != nil {
+		glog.Errorf("failed to parse file id %s", fileId)
+		return
+	}
+	c.diskCaches[0].WriteNeedle(fid.Key, data)
+
 }
+
+func (c *ChunkCache) Shutdown() {
+	c.Lock()
+	defer c.Unlock()
+	for _, diskCache := range c.diskCaches {
+		diskCache.Shutdown()
+	}
+}