MINOR: tinfo: store the number of committed extra streams in the tgroup

In order to be able to enforce global streams limitations, we'll first
have to be able to account how many streams we promised to serve via
frontend muxes. We'll always need to support at least one stream, which
is why here we're only counting extra streams beyond the first one. It
also has the benefit of leaving H1 out of this, and save it from updating
a variable. Also in order to avoid an important update cost, we're storing
this value per thread group. For now only H2 is implemented, but QUIC
should follow shortly and should only count bidirectional streams.

diff --git a/include/haproxy/tinfo-t.h b/include/haproxy/tinfo-t.h
index e691b07c82c62cfb18ce58803b76a15779649302..03d100bff04f000bcf2b226a99d404a1c8330b52 100644 (file)
--- a/include/haproxy/tinfo-t.h
+++ b/include/haproxy/tinfo-t.h
@@ -138,6 +138,7 @@ struct tgroup_ctx {
        struct eb_root timers;            /* wait queue (sorted timers tree, global, accessed under wq_lock) */
 
        uint niced_tasks;                 /* number of niced tasks in this group's run queues */
+       uint committed_extra_streams;     /* sum of extra front streams committed by muxes in this group */
 
        /* pad to cache line (64B) */
        char __pad[0];                    /* unused except to check remaining room */

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 9720ae99c1302bc76119dcf2bd4bb7573745f463..18d2500a8a28c638b07bc16bcbe9685fe67e923f 100644 (file)
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -1446,6 +1446,10 @@ static int h2_init(struct connection *conn, struct proxy *prx, struct session *s
        h2c->st0 = H2_CS_PREFACE;
        h2c->conn = conn;
        h2c->streams_limit = h2c->streams_hard_limit = h2c_max_concurrent_streams(h2c);
+
+       if (!(h2c->flags & H2_CF_IS_BACK) && h2c->streams_hard_limit > 1)
+               _HA_ATOMIC_ADD(&tg_ctx->committed_extra_streams, h2c->streams_hard_limit - 1);
+
        nb_rxbufs = (h2c->flags & H2_CF_IS_BACK) ? h2_be_rxbuf : h2_fe_rxbuf;
        nb_rxbufs = (nb_rxbufs + global.tune.bufsize - 9 - 1) / (global.tune.bufsize - 9);
        nb_rxbufs = MAX(nb_rxbufs, h2c->streams_limit);
@@ -1513,6 +1517,8 @@ static int h2_init(struct connection *conn, struct proxy *prx, struct session *s
        TRACE_LEAVE(H2_EV_H2C_NEW, conn);
        return 0;
   fail_stream:
+       if (!(h2c->flags & H2_CF_IS_BACK) && h2c->streams_hard_limit > 1)
+               _HA_ATOMIC_SUB(&tg_ctx->committed_extra_streams, h2c->streams_hard_limit - 1);
        hpack_dht_free(h2c->ddht);
   fail:
        task_destroy(t);
@@ -1591,6 +1597,9 @@ static void h2_release(struct h2c *h2c)
        if (!conn || !conn_is_reverse(conn))
                HA_ATOMIC_DEC(&h2c->px_counters->open_conns);
 
+       if (!(h2c->flags & H2_CF_IS_BACK) && h2c->streams_hard_limit > 1)
+               _HA_ATOMIC_SUB(&tg_ctx->committed_extra_streams, h2c->streams_hard_limit - 1);
+
        pool_free(pool_head_h2_rx_bufs, h2c->shared_rx_bufs);
        pool_free(pool_head_h2c, h2c);
 
@@ -4175,6 +4184,12 @@ static int h2_conn_reverse(struct h2c *h2c)
                struct server *srv = __objt_server(h2c->conn->target);
                struct proxy *prx = srv->proxy;
 
+               /* the connection was accounted as frontend streams before
+                * reversal, we must undo that accounting now.
+                */
+               if (h2c->streams_hard_limit > 1)
+                       _HA_ATOMIC_SUB(&tg_ctx->committed_extra_streams, h2c->streams_hard_limit - 1);
+
                h2c->flags |= H2_CF_IS_BACK;
 
                h2c->shut_timeout = h2c->timeout = prx->timeout.server;
@@ -4193,6 +4208,10 @@ static int h2_conn_reverse(struct h2c *h2c)
                struct listener *l = __objt_listener(h2c->conn->target);
                struct proxy *prx = l->bind_conf->frontend;
 
+               /* backend connections becoming frontend need accounting. */
+               if (h2c->streams_hard_limit > 1)
+                       _HA_ATOMIC_ADD(&tg_ctx->committed_extra_streams, h2c->streams_hard_limit - 1);
+
                h2c->flags &= ~H2_CF_IS_BACK;
                /* Must manually init max_id so that GOAWAY can be emitted. */
                h2c->max_id = 0;