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Merge pull request #1320 from AudriusButkevicius/cache

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Remove fd cache (ref #1308)
This commit is contained in:
Jakob Borg 2015-02-09 15:10:42 +01:00
commit ebcf4b60f6
7 changed files with 7 additions and 297 deletions
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4
Godeps/Godeps.json generated
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@ -5,10 +5,6 @@
"./cmd/..."
],
"Deps": [
{
"ImportPath": "github.com/AudriusButkevicius/lfu-go",
"Rev": "164bcecceb92fd6037f4d18a8d97b495ec6ef669"
},
{
"ImportPath": "github.com/bkaradzic/go-lz4",
"Rev": "93a831dcee242be64a9cc9803dda84af25932de7"

19
Godeps/_workspace/src/github.com/AudriusButkevicius/lfu-go/LICENSE generated vendored
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@ -1,19 +0,0 @@
Copyright (C) 2012 Dave Grijalva
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.

19
Godeps/_workspace/src/github.com/AudriusButkevicius/lfu-go/README.md generated vendored
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@ -1,19 +0,0 @@
A simple LFU cache for golang. Based on the paper [An O(1) algorithm for implementing the LFU cache eviction scheme](http://dhruvbird.com/lfu.pdf).
Usage:
```go
import "github.com/dgrijalva/lfu-go"
// Make a new thing
c := lfu.New()
// Set some values
c.Set("myKey", myValue)
// Retrieve some values
myValue = c.Get("myKey")
// Evict some values
c.Evict(1)
```

156
Godeps/_workspace/src/github.com/AudriusButkevicius/lfu-go/lfu.go generated vendored
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@ -1,156 +0,0 @@
package lfu
import (
"container/list"
"sync"
)
type Eviction struct {
Key string
Value interface{}
}
type Cache struct {
// If len > UpperBound, cache will automatically evict
// down to LowerBound. If either value is 0, this behavior
// is disabled.
UpperBound int
LowerBound int
values map[string]*cacheEntry
freqs *list.List
len int
lock *sync.Mutex
EvictionChannel chan<- Eviction
}
type cacheEntry struct {
key string
value interface{}
freqNode *list.Element
}
type listEntry struct {
entries map[*cacheEntry]byte
freq int
}
func New() *Cache {
c := new(Cache)
c.values = make(map[string]*cacheEntry)
c.freqs = list.New()
c.lock = new(sync.Mutex)
return c
}
func (c *Cache) Get(key string) interface{} {
c.lock.Lock()
defer c.lock.Unlock()
if e, ok := c.values[key]; ok {
c.increment(e)
return e.value
}
return nil
}
func (c *Cache) Set(key string, value interface{}) {
c.lock.Lock()
defer c.lock.Unlock()
if e, ok := c.values[key]; ok {
// value already exists for key. overwrite
e.value = value
c.increment(e)
} else {
// value doesn't exist. insert
e := new(cacheEntry)
e.key = key
e.value = value
c.values[key] = e
c.increment(e)
c.len++
// bounds mgmt
if c.UpperBound > 0 && c.LowerBound > 0 {
if c.len > c.UpperBound {
c.evict(c.len - c.LowerBound)
}
}
}
}
func (c *Cache) Len() int {
c.lock.Lock()
defer c.lock.Unlock()
return c.len
}
func (c *Cache) Evict(count int) int {
c.lock.Lock()
defer c.lock.Unlock()
return c.evict(count)
}
func (c *Cache) evict(count int) int {
// No lock here so it can be called
// from within the lock (during Set)
var evicted int
for i := 0; i < count; {
if place := c.freqs.Front(); place != nil {
for entry, _ := range place.Value.(*listEntry).entries {
if i < count {
if c.EvictionChannel != nil {
c.EvictionChannel <- Eviction{
Key: entry.key,
Value: entry.value,
}
}
delete(c.values, entry.key)
c.remEntry(place, entry)
evicted++
c.len--
i++
}
}
}
}
return evicted
}
func (c *Cache) increment(e *cacheEntry) {
currentPlace := e.freqNode
var nextFreq int
var nextPlace *list.Element
if currentPlace == nil {
// new entry
nextFreq = 1
nextPlace = c.freqs.Front()
} else {
// move up
nextFreq = currentPlace.Value.(*listEntry).freq + 1
nextPlace = currentPlace.Next()
}
if nextPlace == nil || nextPlace.Value.(*listEntry).freq != nextFreq {
// create a new list entry
li := new(listEntry)
li.freq = nextFreq
li.entries = make(map[*cacheEntry]byte)
if currentPlace != nil {
nextPlace = c.freqs.InsertAfter(li, currentPlace)
} else {
nextPlace = c.freqs.PushFront(li)
}
}
e.freqNode = nextPlace
nextPlace.Value.(*listEntry).entries[e] = 1
if currentPlace != nil {
// remove from current position
c.remEntry(currentPlace, e)
}
}
func (c *Cache) remEntry(place *list.Element, entry *cacheEntry) {
entries := place.Value.(*listEntry).entries
delete(entries, entry)
if len(entries) == 0 {
c.freqs.Remove(place)
}
}

68
Godeps/_workspace/src/github.com/AudriusButkevicius/lfu-go/lfu_test.go generated vendored
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@ -1,68 +0,0 @@
package lfu
import (
"fmt"
"testing"
)
func TestLFU(t *testing.T) {
c := New()
c.Set("a", "a")
if v := c.Get("a"); v != "a" {
t.Errorf("Value was not saved: %v != 'a'", v)
}
if l := c.Len(); l != 1 {
t.Errorf("Length was not updated: %v != 1", l)
}
c.Set("b", "b")
if v := c.Get("b"); v != "b" {
t.Errorf("Value was not saved: %v != 'b'", v)
}
if l := c.Len(); l != 2 {
t.Errorf("Length was not updated: %v != 2", l)
}
c.Get("a")
evicted := c.Evict(1)
if v := c.Get("a"); v != "a" {
t.Errorf("Value was improperly evicted: %v != 'a'", v)
}
if v := c.Get("b"); v != nil {
t.Errorf("Value was not evicted: %v", v)
}
if l := c.Len(); l != 1 {
t.Errorf("Length was not updated: %v != 1", l)
}
if evicted != 1 {
t.Errorf("Number of evicted items is wrong: %v != 1", evicted)
}
}
func TestBoundsMgmt(t *testing.T) {
c := New()
c.UpperBound = 10
c.LowerBound = 5
for i := 0; i < 100; i++ {
c.Set(fmt.Sprintf("%v", i), i)
}
if c.Len() > 10 {
t.Errorf("Bounds management failed to evict properly: %v", c.Len())
}
}
func TestEviction(t *testing.T) {
ch := make(chan Eviction, 1)
c := New()
c.EvictionChannel = ch
c.Set("a", "b")
c.Evict(1)
ev := <-ch
if ev.Key != "a" || ev.Value.(string) != "b" {
t.Error("Incorrect item")
}
}

4
internal/model/model.go
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@ -755,7 +755,9 @@ func (m *Model) Request(deviceID protocol.DeviceID, folder, name string, offset
}
reader = strings.NewReader(target)
} else {
reader, err = os.Open(fn) // XXX: Inefficient, should cache fd?
// Cannot easily cache fd's because we might need to delete the file
// at any moment.
reader, err = os.Open(fn)
if err != nil {
return nil, err
}

34
internal/model/puller.go
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@ -25,8 +25,6 @@ import (
"sync"
"time"
"github.com/AudriusButkevicius/lfu-go"
"github.com/syncthing/protocol"
"github.com/syncthing/syncthing/internal/config"
"github.com/syncthing/syncthing/internal/db"
@ -698,19 +696,6 @@ func (p *Puller) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBl
continue
}
evictionChan := make(chan lfu.Eviction)
fdCache := lfu.New()
fdCache.UpperBound = 50
fdCache.LowerBound = 20
fdCache.EvictionChannel = evictionChan
go func() {
for item := range evictionChan {
item.Value.(*os.File).Close()
}
}()
folderRoots := make(map[string]string)
p.model.fmut.RLock()
for folder, cfg := range p.model.folderCfgs {
@ -721,22 +706,13 @@ func (p *Puller) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBl
for _, block := range state.blocks {
buf = buf[:int(block.Size)]
found := p.model.finder.Iterate(block.Hash, func(folder, file string, index int32) bool {
path := filepath.Join(folderRoots[folder], file)
var fd *os.File
fdi := fdCache.Get(path)
if fdi != nil {
fd = fdi.(*os.File)
} else {
fd, err = os.Open(path)
if err != nil {
return false
}
fdCache.Set(path, fd)
fd, err := os.Open(filepath.Join(folderRoots[folder], file))
if err != nil {
return false
}
_, err = fd.ReadAt(buf, protocol.BlockSize*int64(index))
fd.Close()
if err != nil {
return false
}
@ -782,8 +758,6 @@ func (p *Puller) copierRoutine(in <-chan copyBlocksState, pullChan chan<- pullBl
state.copyDone()
}
}
fdCache.Evict(fdCache.Len())
close(evictionChan)
out <- state.sharedPullerState
}
}