diff --git a/internal/transport/controlbuf.go b/internal/transport/controlbuf.go index 204ba1588bbf..b8e0aa4db275 100644 --- a/internal/transport/controlbuf.go +++ b/internal/transport/controlbuf.go @@ -23,6 +23,7 @@ import ( "fmt" "runtime" "sync" + "sync/atomic" "golang.org/x/net/http2" "golang.org/x/net/http2/hpack" @@ -84,12 +85,24 @@ func (il *itemList) isEmpty() bool { // the control buffer of transport. They represent different aspects of // control tasks, e.g., flow control, settings, streaming resetting, etc. +// maxQueuedTransportResponseFrames is the most queued "transport response" +// frames we will buffer before preventing new reads from occurring on the +// transport. These are control frames sent in response to client requests, +// such as RST_STREAM due to bad headers or settings acks. +const maxQueuedTransportResponseFrames = 50 + +type cbItem interface { + isTransportResponseFrame() bool +} + // registerStream is used to register an incoming stream with loopy writer. type registerStream struct { streamID uint32 wq *writeQuota } +func (*registerStream) isTransportResponseFrame() bool { return false } + // headerFrame is also used to register stream on the client-side. type headerFrame struct { streamID uint32 @@ -102,6 +115,10 @@ type headerFrame struct { onOrphaned func(error) // Valid on client-side } +func (h *headerFrame) isTransportResponseFrame() bool { + return h.cleanup != nil && h.cleanup.rst // Results in a RST_STREAM +} + type cleanupStream struct { streamID uint32 rst bool @@ -109,6 +126,8 @@ type cleanupStream struct { onWrite func() } +func (c *cleanupStream) isTransportResponseFrame() bool { return c.rst } // Results in a RST_STREAM + type dataFrame struct { streamID uint32 endStream bool @@ -119,27 +138,41 @@ type dataFrame struct { onEachWrite func() } +func (*dataFrame) isTransportResponseFrame() bool { return false } + type incomingWindowUpdate struct { streamID uint32 increment uint32 } +func (*incomingWindowUpdate) isTransportResponseFrame() bool { return false } + type outgoingWindowUpdate struct { streamID uint32 increment uint32 } +func (*outgoingWindowUpdate) isTransportResponseFrame() bool { + return false // window updates are throttled by thresholds +} + type incomingSettings struct { ss []http2.Setting } +func (*incomingSettings) isTransportResponseFrame() bool { return true } // Results in a settings ACK + type outgoingSettings struct { ss []http2.Setting } +func (*outgoingSettings) isTransportResponseFrame() bool { return false } + type incomingGoAway struct { } +func (*incomingGoAway) isTransportResponseFrame() bool { return false } + type goAway struct { code http2.ErrCode debugData []byte @@ -147,15 +180,21 @@ type goAway struct { closeConn bool } +func (*goAway) isTransportResponseFrame() bool { return false } + type ping struct { ack bool data [8]byte } +func (*ping) isTransportResponseFrame() bool { return true } + type outFlowControlSizeRequest struct { resp chan uint32 } +func (*outFlowControlSizeRequest) isTransportResponseFrame() bool { return false } + type outStreamState int const ( @@ -238,6 +277,14 @@ type controlBuffer struct { consumerWaiting bool list *itemList err error + + // transportResponseFrames counts the number of queued items that represent + // the response of an action initiated by the peer. trfChan is created + // when transportResponseFrames >= maxQueuedTransportResponseFrames and is + // closed and nilled when transportResponseFrames drops below the + // threshold. Both fields are protected by mu. + transportResponseFrames int + trfChan atomic.Value // *chan struct{} } func newControlBuffer(done <-chan struct{}) *controlBuffer { @@ -248,12 +295,24 @@ func newControlBuffer(done <-chan struct{}) *controlBuffer { } } -func (c *controlBuffer) put(it interface{}) error { +// throttle blocks if there are too many incomingSettings/cleanupStreams in the +// controlbuf. +func (c *controlBuffer) throttle() { + ch, _ := c.trfChan.Load().(*chan struct{}) + if ch != nil { + select { + case <-*ch: + case <-c.done: + } + } +} + +func (c *controlBuffer) put(it cbItem) error { _, err := c.executeAndPut(nil, it) return err } -func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it interface{}) (bool, error) { +func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it cbItem) (bool, error) { var wakeUp bool c.mu.Lock() if c.err != nil { @@ -271,6 +330,15 @@ func (c *controlBuffer) executeAndPut(f func(it interface{}) bool, it interface{ c.consumerWaiting = false } c.list.enqueue(it) + if it.isTransportResponseFrame() { + c.transportResponseFrames++ + if c.transportResponseFrames == maxQueuedTransportResponseFrames { + // We are adding the frame that puts us over the threshold; create + // a throttling channel. + ch := make(chan struct{}) + c.trfChan.Store(&ch) + } + } c.mu.Unlock() if wakeUp { select { @@ -304,7 +372,17 @@ func (c *controlBuffer) get(block bool) (interface{}, error) { return nil, c.err } if !c.list.isEmpty() { - h := c.list.dequeue() + h := c.list.dequeue().(cbItem) + if h.isTransportResponseFrame() { + if c.transportResponseFrames == maxQueuedTransportResponseFrames { + // We are removing the frame that put us over the + // threshold; close and clear the throttling channel. + ch := c.trfChan.Load().(*chan struct{}) + close(*ch) + c.trfChan.Store((*chan struct{})(nil)) + } + c.transportResponseFrames-- + } c.mu.Unlock() return h, nil } diff --git a/internal/transport/http2_client.go b/internal/transport/http2_client.go index 8bb56d2dd60a..41a79c567027 100644 --- a/internal/transport/http2_client.go +++ b/internal/transport/http2_client.go @@ -1245,6 +1245,7 @@ func (t *http2Client) reader() { // loop to keep reading incoming messages on this transport. for { + t.controlBuf.throttle() frame, err := t.framer.fr.ReadFrame() if t.keepaliveEnabled { atomic.CompareAndSwapUint32(&t.activity, 0, 1) diff --git a/internal/transport/http2_server.go b/internal/transport/http2_server.go index beeb2ed33a61..83439b5627d9 100644 --- a/internal/transport/http2_server.go +++ b/internal/transport/http2_server.go @@ -436,6 +436,7 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func( func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.Context, string) context.Context) { defer close(t.readerDone) for { + t.controlBuf.throttle() frame, err := t.framer.fr.ReadFrame() atomic.StoreUint32(&t.activity, 1) if err != nil {