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rxrpc: Send an ACK after every few DATA packets we receive

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Send an ACK if we haven't sent one for the last two packets we've received.
This keeps the other end apprised of where we've got to - which is
important if they're doing slow-start.

We do this in recvmsg so that we can dispatch a packet directly without the
need to wake up the background thread.

This should possibly be made configurable in future.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2016-09-24 18:05:26 +01:00
parent c6a77ff82f
commit 805b21b929
4 changed files with 33 additions and 9 deletions
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3
net/rxrpc/ar-internal.h
View File

@ -533,6 +533,8 @@ struct rxrpc_call {
u16 ackr_skew; /* skew on packet being ACK'd */
rxrpc_serial_t ackr_serial; /* serial of packet being ACK'd */
rxrpc_seq_t ackr_prev_seq; /* previous sequence number received */
rxrpc_seq_t ackr_consumed; /* Highest packet shown consumed */
rxrpc_seq_t ackr_seen; /* Highest packet shown seen */
rxrpc_serial_t ackr_ping; /* Last ping sent */
ktime_t ackr_ping_time; /* Time last ping sent */
@ -695,6 +697,7 @@ enum rxrpc_propose_ack_trace {
rxrpc_propose_ack_respond_to_ack,
rxrpc_propose_ack_respond_to_ping,
rxrpc_propose_ack_retry_tx,
rxrpc_propose_ack_rotate_rx,
rxrpc_propose_ack_terminal_ack,
rxrpc_propose_ack__nr_trace
};

1
net/rxrpc/misc.c
View File

@ -202,6 +202,7 @@ const char rxrpc_propose_ack_traces[rxrpc_propose_ack__nr_trace][8] = {
[rxrpc_propose_ack_respond_to_ack] = "Rsp2Ack",
[rxrpc_propose_ack_respond_to_ping] = "Rsp2Png",
[rxrpc_propose_ack_retry_tx] = "RetryTx",
[rxrpc_propose_ack_rotate_rx] = "RxAck ",
[rxrpc_propose_ack_terminal_ack] = "ClTerm ",
};

25
net/rxrpc/output.c
View File

@ -36,7 +36,9 @@ struct rxrpc_pkt_buffer {
* Fill out an ACK packet.
*/
static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
struct rxrpc_pkt_buffer *pkt)
struct rxrpc_pkt_buffer *pkt,
rxrpc_seq_t *_hard_ack,
rxrpc_seq_t *_top)
{
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top, seq;
@ -48,6 +50,8 @@ static size_t rxrpc_fill_out_ack(struct rxrpc_call *call,
serial = call->ackr_serial;
hard_ack = READ_ONCE(call->rx_hard_ack);
top = smp_load_acquire(&call->rx_top);
*_hard_ack = hard_ack;
*_top = top;
pkt->ack.bufferSpace = htons(8);
pkt->ack.maxSkew = htons(call->ackr_skew);
@ -96,6 +100,7 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
struct msghdr msg;
struct kvec iov[2];
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top;
size_t len, n;
bool ping = false;
int ioc, ret;
@ -146,7 +151,7 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
goto out;
}
ping = (call->ackr_reason == RXRPC_ACK_PING);
n = rxrpc_fill_out_ack(call, pkt);
n = rxrpc_fill_out_ack(call, pkt, &hard_ack, &top);
call->ackr_reason = 0;
spin_unlock_bh(&call->lock);
@ -203,18 +208,22 @@ int rxrpc_send_call_packet(struct rxrpc_call *call, u8 type)
if (ping)
call->ackr_ping_time = ktime_get_real();
if (ret < 0 && call->state < RXRPC_CALL_COMPLETE) {
switch (type) {
case RXRPC_PACKET_TYPE_ACK:
if (type == RXRPC_PACKET_TYPE_ACK &&
call->state < RXRPC_CALL_COMPLETE) {
if (ret < 0) {
clear_bit(RXRPC_CALL_PINGING, &call->flags);
rxrpc_propose_ACK(call, pkt->ack.reason,
ntohs(pkt->ack.maxSkew),
ntohl(pkt->ack.serial),
true, true,
rxrpc_propose_ack_retry_tx);
break;
case RXRPC_PACKET_TYPE_ABORT:
break;
} else {
spin_lock_bh(&call->lock);
if (after(hard_ack, call->ackr_consumed))
call->ackr_consumed = hard_ack;
if (after(top, call->ackr_seen))
call->ackr_seen = top;
spin_unlock_bh(&call->lock);
}
}

13
net/rxrpc/recvmsg.c
View File

@ -201,8 +201,19 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
_debug("%u,%u,%02x", hard_ack, top, flags);
trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
if (flags & RXRPC_LAST_PACKET)
if (flags & RXRPC_LAST_PACKET) {
rxrpc_end_rx_phase(call);
} else {
/* Check to see if there's an ACK that needs sending. */
if (after_eq(hard_ack, call->ackr_consumed + 2) ||
after_eq(top, call->ackr_seen + 2) ||
(hard_ack == top && after(hard_ack, call->ackr_consumed)))
rxrpc_propose_ACK(call, RXRPC_ACK_DELAY, 0, serial,
true, false,
rxrpc_propose_ack_rotate_rx);
if (call->ackr_reason)
rxrpc_send_call_packet(call, RXRPC_PACKET_TYPE_ACK);
}
}
/*