MINOR: mux-quic: complete traces for qcs emission

Add traces for _qc_send_qcs() function. Most notably, traces have been
added each time a qc_stream_desc buffer allocation fails and when stream
or connection flow-level is reached. This should improve debugging for
emission issues.

This must be backported up to 2.7.

diff --git a/src/mux_quic.c b/src/mux_quic.c
index c14b9f25b2c2c26a4fecbd0ddc44cf18b3b6ab10..96b71da2c9d4417db69bf57bf04c57359d9f4cf4 100644 (file)
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -1416,13 +1416,17 @@ static int qcs_xfer_data(struct qcs *qcs, struct buffer *out, struct buffer *in)
 
        BUG_ON_HOT(qcs->tx.offset > qcs->tx.msd);
        /* do not exceed flow control limit */
-       if (qcs->tx.offset + to_xfer > qcs->tx.msd)
+       if (qcs->tx.offset + to_xfer > qcs->tx.msd) {
+               TRACE_DATA("do not exceed stream flow control", QMUX_EV_QCS_SEND, qcc->conn, qcs);
                to_xfer = qcs->tx.msd - qcs->tx.offset;
+       }
 
        BUG_ON_HOT(qcc->tx.offsets > qcc->rfctl.md);
        /* do not overcome flow control limit on connection */
-       if (qcc->tx.offsets + to_xfer > qcc->rfctl.md)
+       if (qcc->tx.offsets + to_xfer > qcc->rfctl.md) {
+               TRACE_DATA("do not exceed conn flow control", QMUX_EV_QCS_SEND, qcc->conn, qcs);
                to_xfer = qcc->rfctl.md - qcc->tx.offsets;
+       }
 
        if (!left && !to_xfer)
                goto out;
@@ -1749,18 +1753,21 @@ static int _qc_send_qcs(struct qcs *qcs, struct list *frms)
        int xfer = 0;
        char fin = 0;
 
+       TRACE_ENTER(QMUX_EV_QCS_SEND, qcc->conn, qcs);
+
        /* Cannot send STREAM on remote unidirectional streams. */
        BUG_ON(quic_stream_is_uni(qcs->id) && quic_stream_is_remote(qcc, qcs->id));
 
        /* Allocate <out> buffer if necessary. */
        if (!out) {
                if (qcc->flags & QC_CF_CONN_FULL)
-                       return 0;
+                       goto out;
 
                out = qc_stream_buf_alloc(qcs->stream, qcs->tx.offset);
                if (!out) {
+                       TRACE_STATE("cannot allocate stream desc buffer", QMUX_EV_QCS_SEND, qcc->conn, qcs);
                        qcc->flags |= QC_CF_CONN_FULL;
-                       return 0;
+                       goto out;
                }
        }
 
@@ -1791,6 +1798,8 @@ static int _qc_send_qcs(struct qcs *qcs, struct list *frms)
                if (ret < 0) { ABORT_NOW(); /* TODO handle this properly */ }
        }
 
+ out:
+       TRACE_LEAVE(QMUX_EV_QCS_SEND, qcc->conn, qcs);
        return xfer;
 }