tcp: Unify tcp_defer_handler and tcp_splice_defer_handler()

These two functions each step through non-spliced and spliced connections
respectively and clean up entries for closed connections.  To avoid
scanning the connection table twice, we merge these into a single function
which scans the unified table and performs the appropriate sort of cleanup
action on each one.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

tcp.c

@@ -1527,21 +1527,23 @@ void tcp_defer_handler(struct ctx *c)
 {
 	int max_conns = c->tcp.conn_count / 100 * TCP_CONN_PRESSURE;
 	int max_files = c->nofile / 100 * TCP_FILE_PRESSURE;
-	struct tcp_tap_conn *conn;
+	union tcp_conn *conn;
 
 	tcp_l2_flags_buf_flush(c);
 	tcp_l2_data_buf_flush(c);
 
-	tcp_splice_defer_handler(c);
+	if ((c->tcp.conn_count < MIN(max_files, max_conns)) &&
-
+	    (c->tcp.splice_conn_count < MIN(max_files / 6, max_conns)))
-	if (c->tcp.conn_count < MIN(max_files, max_conns))
 		return;
 
-	for (conn = CONN(c->tcp.conn_count - 1); conn >= CONN(0); conn--) {
+	for (conn = tc + c->tcp.conn_count - 1; conn >= tc; conn--) {
-		if (conn->c.spliced)
+		if (conn->c.spliced) {
-			continue;
+			if (conn->splice.flags & CLOSING)
-		if (conn->events == CLOSED)
+				tcp_splice_destroy(c, &conn->splice);
-			tcp_conn_destroy(c, conn);
+		} else {
+			if (conn->tap.events == CLOSED)
+				tcp_conn_destroy(c, &conn->tap);
+		}
 	}
 
 }

tcp_conn.h

@@ -200,5 +200,6 @@ extern union tcp_conn tc[];
 
 void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn *new);
 void tcp_table_compact(struct ctx *c, union tcp_conn *hole);
+void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn);
 
 #endif /* TCP_CONN_H */

tcp_splice.c

@@ -111,7 +111,6 @@ static void tcp_splice_conn_epoll_events(uint16_t events,
 	*b |= (events & B_OUT_WAIT) ? EPOLLOUT : 0;
 }
 
-static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn);
 static int tcp_splice_epoll_ctl(const struct ctx *c,
 				struct tcp_splice_conn *conn);
 
@@ -257,7 +256,7 @@ void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn *new)
  * @c:		Execution context
  * @conn:	Connection pointer
  */
-static void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
+void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
 {
 	if (conn->events & SPLICE_ESTABLISHED) {
 		/* Flushing might need to block: don't recycle them. */
@@ -849,24 +848,3 @@ void tcp_splice_timer(struct ctx *c)
 
 	tcp_splice_pipe_refill(c);
 }
-
-/**
- * tcp_splice_defer_handler() - Close connections without timer on file pressure
- * @c:		Execution context
- */
-void tcp_splice_defer_handler(struct ctx *c)
-{
-	int max_conns = c->tcp.conn_count / 100 * TCP_SPLICE_CONN_PRESSURE;
-	int max_files = c->nofile / 100 * TCP_SPLICE_FILE_PRESSURE;
-	struct tcp_splice_conn *conn;
-
-	if (c->tcp.conn_count < MIN(max_files / 6, max_conns))
-		return;
-
-	for (conn = CONN(c->tcp.conn_count - 1); conn >= CONN(0); conn--) {
-		if (!conn->c.spliced)
-			continue;
-		if (conn->flags & CLOSING)
-			tcp_splice_destroy(c, conn);
-	}
-}

tcp_splice.h

@@ -10,6 +10,5 @@ void tcp_sock_handler_splice(struct ctx *c, union epoll_ref ref,
 			     uint32_t events);
 void tcp_splice_init(struct ctx *c);
 void tcp_splice_timer(struct ctx *c);
-void tcp_splice_defer_handler(struct ctx *c);
 
 #endif /* TCP_SPLICE_H */