Commit c46b0183 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

tls: rx: periodically flush socket backlog 



We continuously hold the socket lock during large reads and writes.
This may inflate RTT and negatively impact TCP performance.
Flush the backlog periodically. I tried to pick a flush period (128kB)
which gives significant benefit but the max Bps rate is not yet visibly
impacted.

Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f36068a2

net/core/sock.c

+1 −0
Original line number Diff line number Diff line
@@ -2870,6 +2870,7 @@ void __sk_flush_backlog(struct sock *sk) 
	__release_sock(sk);

	spin_unlock_bh(&sk->sk_lock.slock);

}

EXPORT_SYMBOL_GPL(__sk_flush_backlog);



/**

 * sk_wait_data - wait for data to arrive at sk_receive_queue

net/tls/tls_sw.c

+23 −0
Original line number Diff line number Diff line
@@ -1738,6 +1738,24 @@ static int process_rx_list(struct tls_sw_context_rx *ctx, 
	return copied ? : err;

}



static void

tls_read_flush_backlog(struct sock *sk, struct tls_prot_info *prot,

		       size_t len_left, size_t decrypted, ssize_t done,

		       size_t *flushed_at)

{

	size_t max_rec;



	if (len_left <= decrypted)

		return;



	max_rec = prot->overhead_size - prot->tail_size + TLS_MAX_PAYLOAD_SIZE;

	if (done - *flushed_at < SZ_128K && tcp_inq(sk) > max_rec)

		return;



	*flushed_at = done;

	sk_flush_backlog(sk);

}



int tls_sw_recvmsg(struct sock *sk,

		   struct msghdr *msg,

		   size_t len,
@@ -1750,6 +1768,7 @@ int tls_sw_recvmsg(struct sock *sk, 
	struct sk_psock *psock;

	unsigned char control = 0;

	ssize_t decrypted = 0;

	size_t flushed_at = 0;

	struct strp_msg *rxm;

	struct tls_msg *tlm;

	struct sk_buff *skb;
@@ -1839,6 +1858,10 @@ int tls_sw_recvmsg(struct sock *sk, 
		if (err <= 0)

			goto recv_end;



		/* periodically flush backlog, and feed strparser */

		tls_read_flush_backlog(sk, prot, len, to_decrypt,

				       decrypted + copied, &flushed_at);



		ctx->recv_pkt = NULL;

		__strp_unpause(&ctx->strp);

		__skb_queue_tail(&ctx->rx_list, skb);