MINOR: quic: account for global congestion window

Use the newly defined cshared type to account for the sum of congestion
window of every QUIC connection. This value is stored in global counter
quic_mem_global defined in proto_quic module.

include/haproxy/proto_quic.h

@@ -30,4 +30,6 @@ extern struct protocol proto_quic6;
 
 extern struct quic_dghdlr *quic_dghdlrs;
 
+extern THREAD_LOCAL struct cshared quic_mem_diff;
+
 #endif /* _HAPROXY_PROTO_QUIC_H  */

include/haproxy/quic_cc.h

@@ -29,9 +29,11 @@
 #include <haproxy/api.h>
 #include <haproxy/buf.h>
 #include <haproxy/chunk.h>
+#include <haproxy/proto_quic.h>
 #include <haproxy/quic_cc-t.h>
 #include <haproxy/quic_conn-t.h>
 #include <haproxy/quic_loss.h>
+#include <haproxy/thread.h>
 
 void quic_cc_init(struct quic_cc *cc, struct quic_cc_algo *algo, struct quic_conn *qc);
 void quic_cc_event(struct quic_cc *cc, struct quic_cc_event *ev);
@@ -91,6 +93,7 @@ static inline void quic_cc_path_init(struct quic_cc_path *path, int ipv4, unsign
 	*(size_t *)&path->mtu = max_dgram_sz;
 	path->initial_wnd = QUIC_MIN(10 * max_dgram_sz, QUIC_MAX(max_dgram_sz << 1, 14720U));
 	path->cwnd = path->initial_wnd;
+	cshared_add(&quic_mem_diff, path->cwnd);
 	path->cwnd_last_max = path->cwnd;
 	path->limit_max = max_cwnd;
 	path->limit_min = max_dgram_sz << 1;

src/proto_quic.c

@@ -48,11 +48,15 @@
 #include <haproxy/sock.h>
 #include <haproxy/sock_inet.h>
 #include <haproxy/task.h>
+#include <haproxy/thread.h>
 #include <haproxy/tools.h>
 
 /* per-thread quic datagram handlers */
 struct quic_dghdlr *quic_dghdlrs;
 
+static uint64_t quic_mem_global;
+THREAD_LOCAL struct cshared quic_mem_diff;
+
 /* Size of the internal buffer of QUIC RX buffer at the fd level */
 #define QUIC_RX_BUFSZ  (1UL << 18)
 
@@ -659,6 +663,14 @@ static void quic_bind_tid_reset(struct connection *conn)
 	qc_bind_tid_reset(qc);
 }
 
+static int quic_init_mem(void)
+{
+	/* 1024 is enough to limit modification on global counter but keeping it precise enough even with a lot of threads */
+	cshared_init(&quic_mem_diff, &quic_mem_global, 1024);
+	return 1;
+}
+REGISTER_PER_THREAD_INIT(quic_init_mem);
+
 static int quic_alloc_dghdlrs(void)
 {
 	int i;

src/quic_cc.c

@@ -20,8 +20,10 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+#include <haproxy/proto_quic.h>
 #include <haproxy/quic_cc.h>
 #include <haproxy/quic_pacing.h>
+#include <haproxy/thread.h>
 
 struct quic_cc_algo *default_quic_cc_algo = &quic_cc_algo_cubic;
 
@@ -79,14 +81,19 @@ static int quic_cwnd_may_increase(const struct quic_cc_path *path)
 /* Restore congestion window for <path> to its minimal value. */
 void quic_cc_path_reset(struct quic_cc_path *path)
 {
+	const uint64_t old = path->cwnd;
 	path->cwnd = path->limit_min;
+	cshared_add(&quic_mem_diff, path->cwnd - old);
 }
 
 /* Set congestion window for <path> to <val>. Min and max limits are enforced. */
 void quic_cc_path_set(struct quic_cc_path *path, uint64_t val)
 {
+	const uint64_t old = path->cwnd;
+
 	path->cwnd = QUIC_MIN(val, path->limit_max);
 	path->cwnd = QUIC_MAX(path->cwnd, path->limit_min);
+	cshared_add(&quic_mem_diff, path->cwnd - old);
 
 	path->cwnd_last_max = QUIC_MAX(path->cwnd, path->cwnd_last_max);
 }
@@ -97,9 +104,12 @@ void quic_cc_path_set(struct quic_cc_path *path, uint64_t val)
  */
 void quic_cc_path_inc(struct quic_cc_path *path, uint64_t val)
 {
+	const uint64_t old = path->cwnd;
+
 	if (quic_cwnd_may_increase(path)) {
 		path->cwnd = QUIC_MIN(path->cwnd + val, path->limit_max);
 		path->cwnd = QUIC_MAX(path->cwnd, path->limit_min);
+		cshared_add(&quic_mem_diff, path->cwnd - old);
 
 		path->cwnd_last_max = QUIC_MAX(path->cwnd, path->cwnd_last_max);
 	}

src/quic_conn.c

@@ -1442,6 +1442,10 @@ void quic_conn_release(struct quic_conn *qc)
 		HA_ATOMIC_DEC(&qc->li->rx.quic_curr_accept);
 	}
 
+	/* Substract last congestion window from global memory counter. */
+	cshared_add(&quic_mem_diff, -qc->path->cwnd);
+	qc->path->cwnd = 0;
+
 	/* free remaining stream descriptors */
 	node = eb64_first(&qc->streams_by_id);
 	while (node) {