1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
package filer
import (
"fmt"
"sync"
"sync/atomic"
"time"
"github.com/seaweedfs/seaweedfs/weed/glog"
"github.com/seaweedfs/seaweedfs/weed/util/chunk_cache"
util_http "github.com/seaweedfs/seaweedfs/weed/util/http"
"github.com/seaweedfs/seaweedfs/weed/util/mem"
"github.com/seaweedfs/seaweedfs/weed/wdclient"
)
type ReaderCache struct {
chunkCache chunk_cache.ChunkCache
lookupFileIdFn wdclient.LookupFileIdFunctionType
sync.Mutex
downloaders map[string]*SingleChunkCacher
limit int
}
type SingleChunkCacher struct {
completedTimeNew int64
sync.Mutex
parent *ReaderCache
chunkFileId string
data []byte
err error
cipherKey []byte
isGzipped bool
chunkSize int
shouldCache bool
wg sync.WaitGroup
cacheStartedCh chan struct{}
}
func NewReaderCache(limit int, chunkCache chunk_cache.ChunkCache, lookupFileIdFn wdclient.LookupFileIdFunctionType) *ReaderCache {
return &ReaderCache{
limit: limit,
chunkCache: chunkCache,
lookupFileIdFn: lookupFileIdFn,
downloaders: make(map[string]*SingleChunkCacher),
}
}
func (rc *ReaderCache) MaybeCache(chunkViews *Interval[*ChunkView]) {
if rc.lookupFileIdFn == nil {
return
}
rc.Lock()
defer rc.Unlock()
if len(rc.downloaders) >= rc.limit {
return
}
for x := chunkViews; x != nil; x = x.Next {
chunkView := x.Value
if _, found := rc.downloaders[chunkView.FileId]; found {
continue
}
if rc.chunkCache.IsInCache(chunkView.FileId, true) {
glog.V(4).Infof("%s is in cache", chunkView.FileId)
continue
}
if len(rc.downloaders) >= rc.limit {
// abort when slots are filled
return
}
// glog.V(4).Infof("prefetch %s offset %d", chunkView.FileId, chunkView.ViewOffset)
// cache this chunk if not yet
shouldCache := (uint64(chunkView.ViewOffset) + chunkView.ChunkSize) <= rc.chunkCache.GetMaxFilePartSizeInCache()
cacher := newSingleChunkCacher(rc, chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped, int(chunkView.ChunkSize), shouldCache)
go cacher.startCaching()
<-cacher.cacheStartedCh
rc.downloaders[chunkView.FileId] = cacher
}
return
}
func (rc *ReaderCache) ReadChunkAt(buffer []byte, fileId string, cipherKey []byte, isGzipped bool, offset int64, chunkSize int, shouldCache bool) (int, error) {
rc.Lock()
if cacher, found := rc.downloaders[fileId]; found {
if n, err := cacher.readChunkAt(buffer, offset); n != 0 && err == nil {
rc.Unlock()
return n, err
}
}
if shouldCache || rc.lookupFileIdFn == nil {
n, err := rc.chunkCache.ReadChunkAt(buffer, fileId, uint64(offset))
if n > 0 {
rc.Unlock()
return n, err
}
}
// clean up old downloaders
if len(rc.downloaders) >= rc.limit {
oldestFid, oldestTime := "", time.Now().UnixNano()
for fid, downloader := range rc.downloaders {
completedTime := atomic.LoadInt64(&downloader.completedTimeNew)
if completedTime > 0 && completedTime < oldestTime {
oldestFid, oldestTime = fid, completedTime
}
}
if oldestFid != "" {
oldDownloader := rc.downloaders[oldestFid]
delete(rc.downloaders, oldestFid)
oldDownloader.destroy()
}
}
// glog.V(4).Infof("cache1 %s", fileId)
cacher := newSingleChunkCacher(rc, fileId, cipherKey, isGzipped, chunkSize, shouldCache)
go cacher.startCaching()
<-cacher.cacheStartedCh
rc.downloaders[fileId] = cacher
rc.Unlock()
return cacher.readChunkAt(buffer, offset)
}
func (rc *ReaderCache) UnCache(fileId string) {
rc.Lock()
defer rc.Unlock()
// glog.V(4).Infof("uncache %s", fileId)
if downloader, found := rc.downloaders[fileId]; found {
downloader.destroy()
delete(rc.downloaders, fileId)
}
}
func (rc *ReaderCache) destroy() {
rc.Lock()
defer rc.Unlock()
for _, downloader := range rc.downloaders {
downloader.destroy()
}
}
func newSingleChunkCacher(parent *ReaderCache, fileId string, cipherKey []byte, isGzipped bool, chunkSize int, shouldCache bool) *SingleChunkCacher {
return &SingleChunkCacher{
parent: parent,
chunkFileId: fileId,
cipherKey: cipherKey,
isGzipped: isGzipped,
chunkSize: chunkSize,
shouldCache: shouldCache,
cacheStartedCh: make(chan struct{}),
}
}
func (s *SingleChunkCacher) startCaching() {
s.wg.Add(1)
defer s.wg.Done()
s.Lock()
defer s.Unlock()
s.cacheStartedCh <- struct{}{} // means this has been started
urlStrings, err := s.parent.lookupFileIdFn(s.chunkFileId)
if err != nil {
s.err = fmt.Errorf("operation LookupFileId %s failed, err: %v", s.chunkFileId, err)
return
}
s.data = mem.Allocate(s.chunkSize)
_, s.err = util_http.RetriedFetchChunkData(s.data, urlStrings, s.cipherKey, s.isGzipped, true, 0)
if s.err != nil {
mem.Free(s.data)
s.data = nil
return
}
if s.shouldCache {
s.parent.chunkCache.SetChunk(s.chunkFileId, s.data)
}
atomic.StoreInt64(&s.completedTimeNew, time.Now().UnixNano())
return
}
func (s *SingleChunkCacher) destroy() {
// wait for all reads to finish before destroying the data
s.wg.Wait()
s.Lock()
defer s.Unlock()
if s.data != nil {
mem.Free(s.data)
s.data = nil
close(s.cacheStartedCh)
}
}
func (s *SingleChunkCacher) readChunkAt(buf []byte, offset int64) (int, error) {
s.wg.Add(1)
defer s.wg.Done()
s.Lock()
defer s.Unlock()
if s.err != nil {
return 0, s.err
}
if len(s.data) <= int(offset) {
return 0, nil
}
return copy(buf, s.data[offset:]), nil
}
|
