mirror of https://github.com/qwqdanchun/nps.git
add lock free queue
This commit is contained in:
ffdfgdfg
parent
c2f4510a0f
commit
23b023c562
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@ -263,7 +263,7 @@ func GetPortByAddr(addr string) int {
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return p
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}
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func CopyBuffer(dst io.Writer, src io.Reader) (written int64, err error) {
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func CopyBuffer(dst io.Writer, src io.Reader, label ...string) (written int64, err error) {
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buf := CopyBuff.Get()
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defer CopyBuff.Put(buf)
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for {
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@ -2,10 +2,12 @@ package mux
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import (
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"errors"
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"github.com/astaxie/beego/logs"
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"io"
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"net"
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"strconv"
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"sync"
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"sync/atomic"
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"time"
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"github.com/cnlh/nps/lib/common"
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@ -65,7 +67,7 @@ func (s *conn) Read(buf []byte) (n int, err error) {
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errstr = err.Error()
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}
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d := getM(s.label, int(s.connId))
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d.logs = append(d.logs, s.label+"read "+strconv.Itoa(n)+" "+errstr)
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d.logs = append(d.logs, s.label+"read "+strconv.Itoa(n)+" "+errstr+" "+string(buf[:100]))
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setM(s.label, int(s.connId), d)
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return
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}
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@ -187,11 +189,7 @@ func (Self *ReceiveWindow) RemainingSize() (n uint32) {
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func (Self *ReceiveWindow) ReadSize() (n uint32) {
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// acknowledge the size already read
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Self.bufQueue.mutex.Lock()
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n = Self.readLength
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Self.readLength = 0
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Self.bufQueue.mutex.Unlock()
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return
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return atomic.SwapUint32(&Self.readLength, 0)
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}
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func (Self *ReceiveWindow) CalcSize() {
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@ -270,10 +268,8 @@ copyData:
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//Self.bw.SetCopySize(l)
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pOff += l
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Self.off += uint32(l)
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Self.bufQueue.mutex.Lock()
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Self.readLength += uint32(l)
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atomic.AddUint32(&Self.readLength, uint32(l))
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//logs.Warn("window read length buf len", Self.readLength, Self.bufQueue.Len())
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Self.bufQueue.mutex.Unlock()
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n += l
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l = 0
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//Self.bw.EndRead()
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@ -422,6 +418,7 @@ func (Self *SendWindow) WriteTo() (p []byte, part bool, err error) {
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if len(Self.buf[Self.off:]) > common.MAXIMUM_SEGMENT_SIZE {
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sendSize = common.MAXIMUM_SEGMENT_SIZE
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part = true
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logs.Warn("cut buf by mss")
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} else {
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sendSize = uint32(len(Self.buf[Self.off:]))
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part = false
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@ -430,6 +427,7 @@ func (Self *SendWindow) WriteTo() (p []byte, part bool, err error) {
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// usable window size is small than
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// window MAXIMUM_SEGMENT_SIZE or send buf left
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sendSize = Self.RemainingSize()
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logs.Warn("cut buf by remainingsize", sendSize, len(Self.buf[Self.off:]))
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part = true
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}
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//logs.Warn("send size", sendSize)
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@ -34,6 +34,8 @@ type Mux struct {
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}
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func NewMux(c net.Conn, connType string) *Mux {
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//c.(*net.TCPConn).SetReadBuffer(0)
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//c.(*net.TCPConn).SetWriteBuffer(0)
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m := &Mux{
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conn: c,
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connMap: NewConnMap(),
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@ -173,10 +175,6 @@ func (s *Mux) ping() {
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select {
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case <-ticker.C:
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}
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//Avoid going beyond the scope
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if (math.MaxInt32 - s.id) < 10000 {
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s.id = 0
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}
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now, _ := time.Now().UTC().MarshalText()
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s.sendInfo(common.MUX_PING_FLAG, common.MUX_PING, now)
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if !s.pingTimer.Stop() {
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@ -321,6 +319,10 @@ func (s *Mux) Close() error {
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//get new connId as unique flag
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func (s *Mux) getId() (id int32) {
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//Avoid going beyond the scope
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if (math.MaxInt32 - s.id) < 10000 {
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atomic.SwapInt32(&s.id, 0)
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}
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id = atomic.AddInt32(&s.id, 1)
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if _, ok := s.connMap.Get(id); ok {
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s.getId()
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@ -3,13 +3,16 @@ package mux
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import (
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"bufio"
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"fmt"
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"io"
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"net"
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"net/http"
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"net/http/httputil"
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_ "net/http/pprof"
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"strconv"
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"sync"
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"testing"
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"time"
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"unsafe"
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"github.com/astaxie/beego/logs"
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"github.com/cnlh/nps/lib/common"
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@ -30,20 +33,22 @@ func TestNewMux(t *testing.T) {
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go func() {
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m2 := NewMux(conn2, "tcp")
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for {
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logs.Warn("npc starting accept")
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//logs.Warn("npc starting accept")
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c, err := m2.Accept()
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if err != nil {
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logs.Warn(err)
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continue
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}
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logs.Warn("npc accept success ")
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//logs.Warn("npc accept success ")
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c2, err := net.Dial("tcp", "127.0.0.1:80")
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if err != nil {
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logs.Warn(err)
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c.Close()
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continue
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}
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go func(c2 net.Conn, c net.Conn) {
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//c2.(*net.TCPConn).SetReadBuffer(0)
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//c2.(*net.TCPConn).SetReadBuffer(0)
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go func(c2 net.Conn, c *conn) {
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wg := sync.WaitGroup{}
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wg.Add(1)
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go func() {
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@ -51,7 +56,7 @@ func TestNewMux(t *testing.T) {
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if err != nil {
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c2.Close()
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c.Close()
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logs.Warn("close npc by copy from nps", err)
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logs.Warn("close npc by copy from nps", err, c.connId)
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}
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wg.Done()
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}()
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@ -61,13 +66,13 @@ func TestNewMux(t *testing.T) {
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if err != nil {
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c2.Close()
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c.Close()
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logs.Warn("close npc by copy from server", err)
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logs.Warn("close npc by copy from server", err, c.connId)
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}
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wg.Done()
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}()
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logs.Warn("npc wait")
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//logs.Warn("npc wait")
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wg.Wait()
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}(c2, c)
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}(c2, c.(*conn))
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}
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}()
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@ -78,42 +83,46 @@ func TestNewMux(t *testing.T) {
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logs.Warn(err)
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}
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for {
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logs.Warn("nps starting accept")
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conn, err := l.Accept()
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//logs.Warn("nps starting accept")
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conns, err := l.Accept()
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if err != nil {
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logs.Warn(err)
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continue
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}
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logs.Warn("nps accept success starting new conn")
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//conns.(*net.TCPConn).SetReadBuffer(0)
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//conns.(*net.TCPConn).SetReadBuffer(0)
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//logs.Warn("nps accept success starting new conn")
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tmpCpnn, err := m1.NewConn()
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if err != nil {
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logs.Warn("nps new conn err ", err)
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continue
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}
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logs.Warn("nps new conn success ", tmpCpnn.connId)
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go func(tmpCpnn net.Conn, conn net.Conn) {
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go func(tmpCpnn *conn, conns net.Conn) {
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go func() {
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_, err := common.CopyBuffer(tmpCpnn, conn)
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_, err := common.CopyBuffer(tmpCpnn, conns)
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if err != nil {
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conn.Close()
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conns.Close()
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tmpCpnn.Close()
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logs.Warn("close nps by copy from user")
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logs.Warn("close nps by copy from user", tmpCpnn.connId, err)
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}
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}()
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//time.Sleep(time.Second)
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_, err = common.CopyBuffer(conn, tmpCpnn)
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_, err = common.CopyBuffer(conns, tmpCpnn)
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if err != nil {
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conn.Close()
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conns.Close()
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tmpCpnn.Close()
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logs.Warn("close nps by copy from npc ")
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logs.Warn("close nps by copy from npc ", tmpCpnn.connId, err)
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}
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}(tmpCpnn, conn)
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}(tmpCpnn, conns)
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}
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}()
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go NewLogServer()
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time.Sleep(time.Second * 5)
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//go test_request()
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//for i:=0;i<1000;i++ {
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// go test_raw(i)
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//}
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for {
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time.Sleep(time.Second * 5)
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@ -168,23 +177,40 @@ Connection: keep-alive
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}
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}
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func test_raw() {
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conn, _ := net.Dial("tcp", "127.0.0.1:7777")
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for {
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conn.Write([]byte(`GET /videojs5/test HTTP/1.1
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func test_raw(k int) {
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for i := 0; i < 1; i++ {
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ti := time.Now()
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conn, _ := net.Dial("tcp", "127.0.0.1:7777")
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tid := time.Now()
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conn.Write([]byte(`GET / HTTP/1.1
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Host: 127.0.0.1:7777
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Connection: keep-alive
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`))
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buf := make([]byte, 1000000)
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n, err := conn.Read(buf)
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tiw := time.Now()
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buf := make([]byte, 3572)
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n, err := io.ReadFull(conn, buf)
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//n, err := conn.Read(buf)
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if err != nil {
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logs.Warn("close by read response err", err)
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break
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}
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logs.Warn(n, string(buf[:50]), "\n--------------\n", string(buf[n-50:n]))
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time.Sleep(time.Second)
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//logs.Warn(n, string(buf[:50]), "\n--------------\n", string(buf[n-50:n]))
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//time.Sleep(time.Second)
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err = conn.Close()
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if err != nil {
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logs.Warn("close conn err ", err)
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}
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now := time.Now()
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du := now.Sub(ti).Seconds()
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dud := now.Sub(tid).Seconds()
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duw := now.Sub(tiw).Seconds()
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if du > 1 {
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logs.Warn("duration long", du, dud, duw, k, i)
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}
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if n != 3572 {
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logs.Warn("n loss", n, string(buf))
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}
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}
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}
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@ -199,3 +225,53 @@ func TestNewConn(t *testing.T) {
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logs.Warn(copy(buf[:3], b), len(buf), cap(buf))
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logs.Warn(len(buf), buf[0])
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}
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func TestDQueue(t *testing.T) {
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logs.EnableFuncCallDepth(true)
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logs.SetLogFuncCallDepth(3)
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d := new(bufDequeue)
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d.vals = make([]unsafe.Pointer, 8)
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go func() {
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time.Sleep(time.Second)
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for i := 0; i < 10; i++ {
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logs.Warn(i)
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logs.Warn(d.popTail())
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}
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}()
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go func() {
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time.Sleep(time.Second)
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for i := 0; i < 10; i++ {
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data := "test"
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go logs.Warn(i, unsafe.Pointer(&data), d.pushHead(unsafe.Pointer(&data)))
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}
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}()
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time.Sleep(time.Second * 3)
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}
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func TestChain(t *testing.T) {
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logs.EnableFuncCallDepth(true)
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logs.SetLogFuncCallDepth(3)
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d := new(bufChain)
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d.new(256)
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go func() {
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time.Sleep(time.Second)
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for i := 0; i < 1000; i++ {
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unsa, ok := d.popTail()
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str := (*string)(unsa)
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if ok {
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logs.Warn(i, str, *str, ok)
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} else {
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logs.Warn("nil", i, ok)
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}
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}
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}()
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go func() {
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time.Sleep(time.Second)
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for i := 0; i < 1000; i++ {
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data := "test " + strconv.Itoa(i)
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logs.Warn(data, unsafe.Pointer(&data))
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go d.pushHead(unsafe.Pointer(&data))
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}
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}()
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time.Sleep(time.Second * 10)
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}
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390
lib/mux/queue.go
390
lib/mux/queue.go
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@ -1,19 +1,19 @@
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package mux
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import (
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"container/list"
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"errors"
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"github.com/cnlh/nps/lib/common"
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"io"
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"sync"
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"math"
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"sync/atomic"
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"time"
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"unsafe"
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)
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type QueueOp struct {
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readOp chan struct{}
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cleanOp chan struct{}
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popWait bool
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mutex sync.Mutex
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popWait int32
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}
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func (Self *QueueOp) New() {
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@ -22,15 +22,15 @@ func (Self *QueueOp) New() {
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}
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func (Self *QueueOp) allowPop() (closed bool) {
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Self.mutex.Lock()
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Self.popWait = false
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Self.mutex.Unlock()
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select {
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case Self.readOp <- struct{}{}:
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return false
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case <-Self.cleanOp:
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return true
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if atomic.CompareAndSwapInt32(&Self.popWait, 1, 0) {
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select {
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case Self.readOp <- struct{}{}:
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return false
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case <-Self.cleanOp:
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return true
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}
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}
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return
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}
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func (Self *QueueOp) Clean() {
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@ -40,84 +40,72 @@ func (Self *QueueOp) Clean() {
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}
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type PriorityQueue struct {
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list *list.List
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QueueOp
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highestChain *bufChain
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middleChain *bufChain
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lowestChain *bufChain
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hunger uint8
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}
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func (Self *PriorityQueue) New() {
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Self.list = list.New()
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Self.highestChain = new(bufChain)
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Self.highestChain.new(4)
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Self.middleChain = new(bufChain)
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Self.middleChain.new(32)
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Self.lowestChain = new(bufChain)
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Self.lowestChain.new(256)
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Self.QueueOp.New()
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}
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func (Self *PriorityQueue) Push(packager *common.MuxPackager) {
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Self.mutex.Lock()
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switch packager.Flag {
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case common.MUX_PING_FLAG, common.MUX_PING_RETURN:
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Self.list.PushFront(packager)
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Self.highestChain.pushHead(unsafe.Pointer(packager))
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// the ping package need highest priority
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// prevent ping calculation error
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case common.MUX_CONN_CLOSE:
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Self.insert(packager)
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// the close package may need priority too, set second
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// prevent wait too long to close conn
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case common.MUX_NEW_CONN, common.MUX_NEW_CONN_OK, common.MUX_NEW_CONN_Fail:
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// the new conn package need some priority too
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Self.middleChain.pushHead(unsafe.Pointer(packager))
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default:
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Self.list.PushBack(packager)
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Self.lowestChain.pushHead(unsafe.Pointer(packager))
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}
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if Self.popWait {
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Self.mutex.Unlock()
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Self.allowPop()
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return
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}
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Self.mutex.Unlock()
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Self.allowPop()
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return
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}
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func (Self *PriorityQueue) insert(packager *common.MuxPackager) {
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element := Self.list.Back()
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for {
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if element == nil { // PriorityQueue dose not have any of msg package with this close package id
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element = Self.list.Front()
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if element != nil {
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Self.list.InsertAfter(packager, element)
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// insert close package to second
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} else {
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Self.list.PushFront(packager)
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// list is empty, push to front
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}
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break
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}
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if element.Value.(*common.MuxPackager).Flag == common.MUX_NEW_MSG &&
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element.Value.(*common.MuxPackager).Id == packager.Id {
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Self.list.InsertAfter(packager, element) // PriorityQueue has some msg package
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// with this close package id, insert close package after last msg package
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break
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}
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element = element.Prev()
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}
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}
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func (Self *PriorityQueue) Pop() (packager *common.MuxPackager) {
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Self.mutex.Lock()
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element := Self.list.Front()
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if element != nil {
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packager = element.Value.(*common.MuxPackager)
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Self.list.Remove(element)
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Self.mutex.Unlock()
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||||
startPop:
|
||||
ptr, ok := Self.highestChain.popTail()
|
||||
if ok {
|
||||
packager = (*common.MuxPackager)(ptr)
|
||||
return
|
||||
}
|
||||
Self.popWait = true // PriorityQueue is empty, notice Push method
|
||||
Self.mutex.Unlock()
|
||||
select {
|
||||
case <-Self.readOp:
|
||||
return Self.Pop()
|
||||
case <-Self.cleanOp:
|
||||
return nil
|
||||
if Self.hunger < 100 {
|
||||
ptr, ok = Self.middleChain.popTail()
|
||||
if ok {
|
||||
packager = (*common.MuxPackager)(ptr)
|
||||
Self.hunger++
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (Self *PriorityQueue) Len() (n int) {
|
||||
n = Self.list.Len()
|
||||
return
|
||||
ptr, ok = Self.lowestChain.popTail()
|
||||
if ok {
|
||||
packager = (*common.MuxPackager)(ptr)
|
||||
if Self.hunger > 0 {
|
||||
Self.hunger = uint8(Self.hunger / 2)
|
||||
}
|
||||
return
|
||||
}
|
||||
// PriorityQueue is empty, notice Push method
|
||||
if atomic.CompareAndSwapInt32(&Self.popWait, 0, 1) {
|
||||
select {
|
||||
case <-Self.readOp:
|
||||
goto startPop
|
||||
case <-Self.cleanOp:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
goto startPop
|
||||
}
|
||||
|
||||
type ListElement struct {
|
||||
|
|
@ -137,36 +125,36 @@ func (Self *ListElement) New(buf []byte, l uint16, part bool) (err error) {
|
|||
}
|
||||
|
||||
type FIFOQueue struct {
|
||||
list []*ListElement
|
||||
QueueOp
|
||||
chain *bufChain
|
||||
length uint32
|
||||
stopOp chan struct{}
|
||||
timeout time.Time
|
||||
QueueOp
|
||||
}
|
||||
|
||||
func (Self *FIFOQueue) New() {
|
||||
Self.QueueOp.New()
|
||||
Self.chain = new(bufChain)
|
||||
Self.chain.new(64)
|
||||
Self.stopOp = make(chan struct{}, 1)
|
||||
}
|
||||
|
||||
func (Self *FIFOQueue) Push(element *ListElement) {
|
||||
Self.mutex.Lock()
|
||||
Self.list = append(Self.list, element)
|
||||
Self.chain.pushHead(unsafe.Pointer(element))
|
||||
Self.length += uint32(element.l)
|
||||
if Self.popWait {
|
||||
Self.mutex.Unlock()
|
||||
Self.allowPop()
|
||||
return
|
||||
}
|
||||
Self.mutex.Unlock()
|
||||
Self.allowPop()
|
||||
return
|
||||
}
|
||||
|
||||
func (Self *FIFOQueue) Pop() (element *ListElement, err error) {
|
||||
Self.mutex.Lock()
|
||||
if len(Self.list) == 0 {
|
||||
Self.popWait = true
|
||||
Self.mutex.Unlock()
|
||||
startPop:
|
||||
ptr, ok := Self.chain.popTail()
|
||||
if ok {
|
||||
element = (*ListElement)(ptr)
|
||||
Self.length -= uint32(element.l)
|
||||
return
|
||||
}
|
||||
if atomic.CompareAndSwapInt32(&Self.popWait, 0, 1) {
|
||||
t := Self.timeout.Sub(time.Now())
|
||||
if t <= 0 {
|
||||
t = time.Minute
|
||||
|
|
@ -175,7 +163,7 @@ func (Self *FIFOQueue) Pop() (element *ListElement, err error) {
|
|||
defer timer.Stop()
|
||||
select {
|
||||
case <-Self.readOp:
|
||||
Self.mutex.Lock()
|
||||
goto startPop
|
||||
case <-Self.cleanOp:
|
||||
return
|
||||
case <-Self.stopOp:
|
||||
|
|
@ -186,11 +174,7 @@ func (Self *FIFOQueue) Pop() (element *ListElement, err error) {
|
|||
return
|
||||
}
|
||||
}
|
||||
element = Self.list[0]
|
||||
Self.list = Self.list[1:]
|
||||
Self.length -= uint32(element.l)
|
||||
Self.mutex.Unlock()
|
||||
return
|
||||
goto startPop
|
||||
}
|
||||
|
||||
func (Self *FIFOQueue) Len() (n uint32) {
|
||||
|
|
@ -204,3 +188,231 @@ func (Self *FIFOQueue) Stop() {
|
|||
func (Self *FIFOQueue) SetTimeOut(t time.Time) {
|
||||
Self.timeout = t
|
||||
}
|
||||
|
||||
// https://golang.org/src/sync/poolqueue.go
|
||||
|
||||
type bufDequeue struct {
|
||||
// headTail packs together a 32-bit head index and a 32-bit
|
||||
// tail index. Both are indexes into vals modulo len(vals)-1.
|
||||
//
|
||||
// tail = index of oldest data in queue
|
||||
// head = index of next slot to fill
|
||||
//
|
||||
// Slots in the range [tail, head) are owned by consumers.
|
||||
// A consumer continues to own a slot outside this range until
|
||||
// it nils the slot, at which point ownership passes to the
|
||||
// producer.
|
||||
//
|
||||
// The head index is stored in the most-significant bits so
|
||||
// that we can atomically add to it and the overflow is
|
||||
// harmless.
|
||||
headTail uint64
|
||||
|
||||
// vals is a ring buffer of interface{} values stored in this
|
||||
// dequeue. The size of this must be a power of 2.
|
||||
//
|
||||
// A slot is still in use until *both* the tail
|
||||
// index has moved beyond it and typ has been set to nil. This
|
||||
// is set to nil atomically by the consumer and read
|
||||
// atomically by the producer.
|
||||
vals []unsafe.Pointer
|
||||
}
|
||||
|
||||
const dequeueBits = 32
|
||||
|
||||
// dequeueLimit is the maximum size of a bufDequeue.
|
||||
//
|
||||
// This must be at most (1<<dequeueBits)/2 because detecting fullness
|
||||
// depends on wrapping around the ring buffer without wrapping around
|
||||
// the index. We divide by 4 so this fits in an int on 32-bit.
|
||||
const dequeueLimit = (1 << dequeueBits) / 4
|
||||
|
||||
func (d *bufDequeue) unpack(ptrs uint64) (head, tail uint32) {
|
||||
const mask = 1<<dequeueBits - 1
|
||||
head = uint32((ptrs >> dequeueBits) & mask)
|
||||
tail = uint32(ptrs & mask)
|
||||
return
|
||||
}
|
||||
|
||||
func (d *bufDequeue) pack(head, tail uint32) uint64 {
|
||||
const mask = 1<<dequeueBits - 1
|
||||
return (uint64(head) << dequeueBits) |
|
||||
uint64(tail&mask)
|
||||
}
|
||||
|
||||
// pushHead adds val at the head of the queue. It returns false if the
|
||||
// queue is full.
|
||||
func (d *bufDequeue) pushHead(val unsafe.Pointer) bool {
|
||||
var slot *unsafe.Pointer
|
||||
for {
|
||||
ptrs := atomic.LoadUint64(&d.headTail)
|
||||
head, tail := d.unpack(ptrs)
|
||||
if (tail+uint32(len(d.vals)))&(1<<dequeueBits-1) == head {
|
||||
// Queue is full.
|
||||
return false
|
||||
}
|
||||
ptrs2 := d.pack(head+1, tail)
|
||||
if atomic.CompareAndSwapUint64(&d.headTail, ptrs, ptrs2) {
|
||||
slot = &d.vals[head&uint32(len(d.vals)-1)]
|
||||
break
|
||||
}
|
||||
}
|
||||
// The head slot is free, so we own it.
|
||||
*slot = val
|
||||
return true
|
||||
}
|
||||
|
||||
// popTail removes and returns the element at the tail of the queue.
|
||||
// It returns false if the queue is empty. It may be called by any
|
||||
// number of consumers.
|
||||
func (d *bufDequeue) popTail() (unsafe.Pointer, bool) {
|
||||
ptrs := atomic.LoadUint64(&d.headTail)
|
||||
head, tail := d.unpack(ptrs)
|
||||
if tail == head {
|
||||
// Queue is empty.
|
||||
return nil, false
|
||||
}
|
||||
slot := &d.vals[tail&uint32(len(d.vals)-1)]
|
||||
for {
|
||||
typ := atomic.LoadPointer(slot)
|
||||
if typ != nil {
|
||||
break
|
||||
}
|
||||
// Another goroutine is still pushing data on the tail.
|
||||
}
|
||||
|
||||
// We now own slot.
|
||||
val := *slot
|
||||
|
||||
// Tell pushHead that we're done with this slot. Zeroing the
|
||||
// slot is also important so we don't leave behind references
|
||||
// that could keep this object live longer than necessary.
|
||||
//
|
||||
// We write to val first and then publish that we're done with
|
||||
atomic.StorePointer(slot, nil)
|
||||
// At this point pushHead owns the slot.
|
||||
if tail < math.MaxUint32 {
|
||||
atomic.AddUint64(&d.headTail, 1)
|
||||
} else {
|
||||
atomic.AddUint64(&d.headTail, ^uint64(math.MaxUint32-1))
|
||||
}
|
||||
return val, true
|
||||
}
|
||||
|
||||
// bufChain is a dynamically-sized version of bufDequeue.
|
||||
//
|
||||
// This is implemented as a doubly-linked list queue of poolDequeues
|
||||
// where each dequeue is double the size of the previous one. Once a
|
||||
// dequeue fills up, this allocates a new one and only ever pushes to
|
||||
// the latest dequeue. Pops happen from the other end of the list and
|
||||
// once a dequeue is exhausted, it gets removed from the list.
|
||||
type bufChain struct {
|
||||
// head is the bufDequeue to push to. This is only accessed
|
||||
// by the producer, so doesn't need to be synchronized.
|
||||
head *bufChainElt
|
||||
|
||||
// tail is the bufDequeue to popTail from. This is accessed
|
||||
// by consumers, so reads and writes must be atomic.
|
||||
tail *bufChainElt
|
||||
chainStatus int32
|
||||
}
|
||||
|
||||
type bufChainElt struct {
|
||||
bufDequeue
|
||||
|
||||
// next and prev link to the adjacent poolChainElts in this
|
||||
// bufChain.
|
||||
//
|
||||
// next is written atomically by the producer and read
|
||||
// atomically by the consumer. It only transitions from nil to
|
||||
// non-nil.
|
||||
//
|
||||
// prev is written atomically by the consumer and read
|
||||
// atomically by the producer. It only transitions from
|
||||
// non-nil to nil.
|
||||
next, prev *bufChainElt
|
||||
}
|
||||
|
||||
func storePoolChainElt(pp **bufChainElt, v *bufChainElt) {
|
||||
atomic.StorePointer((*unsafe.Pointer)(unsafe.Pointer(pp)), unsafe.Pointer(v))
|
||||
}
|
||||
|
||||
func loadPoolChainElt(pp **bufChainElt) *bufChainElt {
|
||||
return (*bufChainElt)(atomic.LoadPointer((*unsafe.Pointer)(unsafe.Pointer(pp))))
|
||||
}
|
||||
|
||||
func (c *bufChain) new(initSize int) {
|
||||
// Initialize the chain.
|
||||
// initSize must be a power of 2
|
||||
d := new(bufChainElt)
|
||||
d.vals = make([]unsafe.Pointer, initSize)
|
||||
storePoolChainElt(&c.head, d)
|
||||
storePoolChainElt(&c.tail, d)
|
||||
}
|
||||
|
||||
func (c *bufChain) pushHead(val unsafe.Pointer) {
|
||||
for {
|
||||
d := loadPoolChainElt(&c.head)
|
||||
|
||||
if d.pushHead(val) {
|
||||
return
|
||||
}
|
||||
|
||||
// The current dequeue is full. Allocate a new one of twice
|
||||
// the size.
|
||||
if atomic.CompareAndSwapInt32(&c.chainStatus, 0, 1) {
|
||||
newSize := len(d.vals) * 2
|
||||
if newSize >= dequeueLimit {
|
||||
// Can't make it any bigger.
|
||||
newSize = dequeueLimit
|
||||
}
|
||||
|
||||
d2 := &bufChainElt{prev: d}
|
||||
d2.vals = make([]unsafe.Pointer, newSize)
|
||||
storePoolChainElt(&c.head, d2)
|
||||
storePoolChainElt(&d.next, d2)
|
||||
d2.pushHead(val)
|
||||
atomic.SwapInt32(&c.chainStatus, 0)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (c *bufChain) popTail() (unsafe.Pointer, bool) {
|
||||
d := loadPoolChainElt(&c.tail)
|
||||
if d == nil {
|
||||
return nil, false
|
||||
}
|
||||
|
||||
for {
|
||||
// It's important that we load the next pointer
|
||||
// *before* popping the tail. In general, d may be
|
||||
// transiently empty, but if next is non-nil before
|
||||
// the pop and the pop fails, then d is permanently
|
||||
// empty, which is the only condition under which it's
|
||||
// safe to drop d from the chain.
|
||||
d2 := loadPoolChainElt(&d.next)
|
||||
|
||||
if val, ok := d.popTail(); ok {
|
||||
return val, ok
|
||||
}
|
||||
|
||||
if d2 == nil {
|
||||
// This is the only dequeue. It's empty right
|
||||
// now, but could be pushed to in the future.
|
||||
return nil, false
|
||||
}
|
||||
|
||||
// The tail of the chain has been drained, so move on
|
||||
// to the next dequeue. Try to drop it from the chain
|
||||
// so the next pop doesn't have to look at the empty
|
||||
// dequeue again.
|
||||
if atomic.CompareAndSwapPointer((*unsafe.Pointer)(unsafe.Pointer(&c.tail)), unsafe.Pointer(d), unsafe.Pointer(d2)) {
|
||||
// We won the race. Clear the prev pointer so
|
||||
// the garbage collector can collect the empty
|
||||
// dequeue and so popHead doesn't back up
|
||||
// further than necessary.
|
||||
storePoolChainElt(&d2.prev, nil)
|
||||
}
|
||||
d = d2
|
||||
}
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue