mirror of
https://github.com/genuinetools/reg.git
synced 2024-08-21 14:20:23 -04:00
237 lines
6.3 KiB
Go
237 lines
6.3 KiB
Go
![]() |
/*
|
||
|
*
|
||
|
* Copyright 2014 gRPC authors.
|
||
|
*
|
||
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
* you may not use this file except in compliance with the License.
|
||
|
* You may obtain a copy of the License at
|
||
|
*
|
||
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
*
|
||
|
* Unless required by applicable law or agreed to in writing, software
|
||
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
* See the License for the specific language governing permissions and
|
||
|
* limitations under the License.
|
||
|
*
|
||
|
*/
|
||
|
|
||
|
package transport
|
||
|
|
||
|
import (
|
||
|
"fmt"
|
||
|
"math"
|
||
|
"sync"
|
||
|
"sync/atomic"
|
||
|
"time"
|
||
|
)
|
||
|
|
||
|
const (
|
||
|
// The default value of flow control window size in HTTP2 spec.
|
||
|
defaultWindowSize = 65535
|
||
|
// The initial window size for flow control.
|
||
|
initialWindowSize = defaultWindowSize // for an RPC
|
||
|
infinity = time.Duration(math.MaxInt64)
|
||
|
defaultClientKeepaliveTime = infinity
|
||
|
defaultClientKeepaliveTimeout = 20 * time.Second
|
||
|
defaultMaxStreamsClient = 100
|
||
|
defaultMaxConnectionIdle = infinity
|
||
|
defaultMaxConnectionAge = infinity
|
||
|
defaultMaxConnectionAgeGrace = infinity
|
||
|
defaultServerKeepaliveTime = 2 * time.Hour
|
||
|
defaultServerKeepaliveTimeout = 20 * time.Second
|
||
|
defaultKeepalivePolicyMinTime = 5 * time.Minute
|
||
|
// max window limit set by HTTP2 Specs.
|
||
|
maxWindowSize = math.MaxInt32
|
||
|
// defaultWriteQuota is the default value for number of data
|
||
|
// bytes that each stream can schedule before some of it being
|
||
|
// flushed out.
|
||
|
defaultWriteQuota = 64 * 1024
|
||
|
)
|
||
|
|
||
|
// writeQuota is a soft limit on the amount of data a stream can
|
||
|
// schedule before some of it is written out.
|
||
|
type writeQuota struct {
|
||
|
quota int32
|
||
|
// get waits on read from when quota goes less than or equal to zero.
|
||
|
// replenish writes on it when quota goes positive again.
|
||
|
ch chan struct{}
|
||
|
// done is triggered in error case.
|
||
|
done <-chan struct{}
|
||
|
}
|
||
|
|
||
|
func newWriteQuota(sz int32, done <-chan struct{}) *writeQuota {
|
||
|
return &writeQuota{
|
||
|
quota: sz,
|
||
|
ch: make(chan struct{}, 1),
|
||
|
done: done,
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func (w *writeQuota) get(sz int32) error {
|
||
|
for {
|
||
|
if atomic.LoadInt32(&w.quota) > 0 {
|
||
|
atomic.AddInt32(&w.quota, -sz)
|
||
|
return nil
|
||
|
}
|
||
|
select {
|
||
|
case <-w.ch:
|
||
|
continue
|
||
|
case <-w.done:
|
||
|
return errStreamDone
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func (w *writeQuota) replenish(n int) {
|
||
|
sz := int32(n)
|
||
|
a := atomic.AddInt32(&w.quota, sz)
|
||
|
b := a - sz
|
||
|
if b <= 0 && a > 0 {
|
||
|
select {
|
||
|
case w.ch <- struct{}{}:
|
||
|
default:
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
type trInFlow struct {
|
||
|
limit uint32
|
||
|
unacked uint32
|
||
|
effectiveWindowSize uint32
|
||
|
}
|
||
|
|
||
|
func (f *trInFlow) newLimit(n uint32) uint32 {
|
||
|
d := n - f.limit
|
||
|
f.limit = n
|
||
|
f.updateEffectiveWindowSize()
|
||
|
return d
|
||
|
}
|
||
|
|
||
|
func (f *trInFlow) onData(n uint32) uint32 {
|
||
|
f.unacked += n
|
||
|
if f.unacked >= f.limit/4 {
|
||
|
w := f.unacked
|
||
|
f.unacked = 0
|
||
|
f.updateEffectiveWindowSize()
|
||
|
return w
|
||
|
}
|
||
|
f.updateEffectiveWindowSize()
|
||
|
return 0
|
||
|
}
|
||
|
|
||
|
func (f *trInFlow) reset() uint32 {
|
||
|
w := f.unacked
|
||
|
f.unacked = 0
|
||
|
f.updateEffectiveWindowSize()
|
||
|
return w
|
||
|
}
|
||
|
|
||
|
func (f *trInFlow) updateEffectiveWindowSize() {
|
||
|
atomic.StoreUint32(&f.effectiveWindowSize, f.limit-f.unacked)
|
||
|
}
|
||
|
|
||
|
func (f *trInFlow) getSize() uint32 {
|
||
|
return atomic.LoadUint32(&f.effectiveWindowSize)
|
||
|
}
|
||
|
|
||
|
// TODO(mmukhi): Simplify this code.
|
||
|
// inFlow deals with inbound flow control
|
||
|
type inFlow struct {
|
||
|
mu sync.Mutex
|
||
|
// The inbound flow control limit for pending data.
|
||
|
limit uint32
|
||
|
// pendingData is the overall data which have been received but not been
|
||
|
// consumed by applications.
|
||
|
pendingData uint32
|
||
|
// The amount of data the application has consumed but grpc has not sent
|
||
|
// window update for them. Used to reduce window update frequency.
|
||
|
pendingUpdate uint32
|
||
|
// delta is the extra window update given by receiver when an application
|
||
|
// is reading data bigger in size than the inFlow limit.
|
||
|
delta uint32
|
||
|
}
|
||
|
|
||
|
// newLimit updates the inflow window to a new value n.
|
||
|
// It assumes that n is always greater than the old limit.
|
||
|
func (f *inFlow) newLimit(n uint32) uint32 {
|
||
|
f.mu.Lock()
|
||
|
d := n - f.limit
|
||
|
f.limit = n
|
||
|
f.mu.Unlock()
|
||
|
return d
|
||
|
}
|
||
|
|
||
|
func (f *inFlow) maybeAdjust(n uint32) uint32 {
|
||
|
if n > uint32(math.MaxInt32) {
|
||
|
n = uint32(math.MaxInt32)
|
||
|
}
|
||
|
f.mu.Lock()
|
||
|
// estSenderQuota is the receiver's view of the maximum number of bytes the sender
|
||
|
// can send without a window update.
|
||
|
estSenderQuota := int32(f.limit - (f.pendingData + f.pendingUpdate))
|
||
|
// estUntransmittedData is the maximum number of bytes the sends might not have put
|
||
|
// on the wire yet. A value of 0 or less means that we have already received all or
|
||
|
// more bytes than the application is requesting to read.
|
||
|
estUntransmittedData := int32(n - f.pendingData) // Casting into int32 since it could be negative.
|
||
|
// This implies that unless we send a window update, the sender won't be able to send all the bytes
|
||
|
// for this message. Therefore we must send an update over the limit since there's an active read
|
||
|
// request from the application.
|
||
|
if estUntransmittedData > estSenderQuota {
|
||
|
// Sender's window shouldn't go more than 2^31 - 1 as specified in the HTTP spec.
|
||
|
if f.limit+n > maxWindowSize {
|
||
|
f.delta = maxWindowSize - f.limit
|
||
|
} else {
|
||
|
// Send a window update for the whole message and not just the difference between
|
||
|
// estUntransmittedData and estSenderQuota. This will be helpful in case the message
|
||
|
// is padded; We will fallback on the current available window(at least a 1/4th of the limit).
|
||
|
f.delta = n
|
||
|
}
|
||
|
f.mu.Unlock()
|
||
|
return f.delta
|
||
|
}
|
||
|
f.mu.Unlock()
|
||
|
return 0
|
||
|
}
|
||
|
|
||
|
// onData is invoked when some data frame is received. It updates pendingData.
|
||
|
func (f *inFlow) onData(n uint32) error {
|
||
|
f.mu.Lock()
|
||
|
f.pendingData += n
|
||
|
if f.pendingData+f.pendingUpdate > f.limit+f.delta {
|
||
|
limit := f.limit
|
||
|
rcvd := f.pendingData + f.pendingUpdate
|
||
|
f.mu.Unlock()
|
||
|
return fmt.Errorf("received %d-bytes data exceeding the limit %d bytes", rcvd, limit)
|
||
|
}
|
||
|
f.mu.Unlock()
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// onRead is invoked when the application reads the data. It returns the window size
|
||
|
// to be sent to the peer.
|
||
|
func (f *inFlow) onRead(n uint32) uint32 {
|
||
|
f.mu.Lock()
|
||
|
if f.pendingData == 0 {
|
||
|
f.mu.Unlock()
|
||
|
return 0
|
||
|
}
|
||
|
f.pendingData -= n
|
||
|
if n > f.delta {
|
||
|
n -= f.delta
|
||
|
f.delta = 0
|
||
|
} else {
|
||
|
f.delta -= n
|
||
|
n = 0
|
||
|
}
|
||
|
f.pendingUpdate += n
|
||
|
if f.pendingUpdate >= f.limit/4 {
|
||
|
wu := f.pendingUpdate
|
||
|
f.pendingUpdate = 0
|
||
|
f.mu.Unlock()
|
||
|
return wu
|
||
|
}
|
||
|
f.mu.Unlock()
|
||
|
return 0
|
||
|
}
|