6.8-stable review patch. If anyone has any objections, please let me know.
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From: David Howells dhowells@redhat.com
[ Upstream commit 012b7206918dcc5a4dcf1432b3e643114c95957e ]
Only generate one ACK packet for all the subpackets in a jumbo packet. If we would like to generate more than one ACK, we prioritise them base on their reason code, in the order, highest first:
OutOfSeq > NoSpace > ExceedsWin > Duplicate > Requested > Delay > Idle
For the first four, we reference the lowest offending subpacket; for the last three, the highest.
This reduces the number of ACKs we end up transmitting to one per UDP packet transmitted to reduce network loading and packet parsing.
Fixes: 5d7edbc9231e ("rxrpc: Get rid of the Rx ring") Signed-off-by: David Howells dhowells@redhat.com cc: Marc Dionne marc.dionne@auristor.com cc: linux-afs@lists.infradead.org Reviewed-by: Jeffrey Altman <jaltman@auristor.com mailto:jaltman@auristor.com> Link: https://lore.kernel.org/r/20240503150749.1001323-3-dhowells@redhat.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/rxrpc/input.c | 46 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 11 deletions(-)
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index f7304e06aadca..5dfda1ac51dda 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -9,6 +9,17 @@
#include "ar-internal.h"
+/* Override priority when generating ACKs for received DATA */ +static const u8 rxrpc_ack_priority[RXRPC_ACK__INVALID] = { + [RXRPC_ACK_IDLE] = 1, + [RXRPC_ACK_DELAY] = 2, + [RXRPC_ACK_REQUESTED] = 3, + [RXRPC_ACK_DUPLICATE] = 4, + [RXRPC_ACK_EXCEEDS_WINDOW] = 5, + [RXRPC_ACK_NOSPACE] = 6, + [RXRPC_ACK_OUT_OF_SEQUENCE] = 7, +}; + static void rxrpc_proto_abort(struct rxrpc_call *call, rxrpc_seq_t seq, enum rxrpc_abort_reason why) { @@ -366,7 +377,7 @@ static void rxrpc_input_queue_data(struct rxrpc_call *call, struct sk_buff *skb, * Process a DATA packet. */ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb, - bool *_notify) + bool *_notify, rxrpc_serial_t *_ack_serial, int *_ack_reason) { struct rxrpc_skb_priv *sp = rxrpc_skb(skb); struct sk_buff *oos; @@ -419,8 +430,6 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb, /* Send an immediate ACK if we fill in a hole */ else if (!skb_queue_empty(&call->rx_oos_queue)) ack_reason = RXRPC_ACK_DELAY; - else - call->ackr_nr_unacked++;
window++; if (after(window, wtop)) { @@ -498,12 +507,16 @@ static void rxrpc_input_data_one(struct rxrpc_call *call, struct sk_buff *skb, }
send_ack: - if (ack_reason >= 0) - rxrpc_send_ACK(call, ack_reason, serial, - rxrpc_propose_ack_input_data); - else - rxrpc_propose_delay_ACK(call, serial, - rxrpc_propose_ack_input_data); + if (ack_reason >= 0) { + if (rxrpc_ack_priority[ack_reason] > rxrpc_ack_priority[*_ack_reason]) { + *_ack_serial = serial; + *_ack_reason = ack_reason; + } else if (rxrpc_ack_priority[ack_reason] == rxrpc_ack_priority[*_ack_reason] && + ack_reason == RXRPC_ACK_REQUESTED) { + *_ack_serial = serial; + *_ack_reason = ack_reason; + } + } }
/* @@ -514,9 +527,11 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb struct rxrpc_jumbo_header jhdr; struct rxrpc_skb_priv *sp = rxrpc_skb(skb), *jsp; struct sk_buff *jskb; + rxrpc_serial_t ack_serial = 0; unsigned int offset = sizeof(struct rxrpc_wire_header); unsigned int len = skb->len - offset; bool notify = false; + int ack_reason = 0;
while (sp->hdr.flags & RXRPC_JUMBO_PACKET) { if (len < RXRPC_JUMBO_SUBPKTLEN) @@ -536,7 +551,7 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb jsp = rxrpc_skb(jskb); jsp->offset = offset; jsp->len = RXRPC_JUMBO_DATALEN; - rxrpc_input_data_one(call, jskb, ¬ify); + rxrpc_input_data_one(call, jskb, ¬ify, &ack_serial, &ack_reason); rxrpc_free_skb(jskb, rxrpc_skb_put_jumbo_subpacket);
sp->hdr.flags = jhdr.flags; @@ -549,7 +564,16 @@ static bool rxrpc_input_split_jumbo(struct rxrpc_call *call, struct sk_buff *skb
sp->offset = offset; sp->len = len; - rxrpc_input_data_one(call, skb, ¬ify); + rxrpc_input_data_one(call, skb, ¬ify, &ack_serial, &ack_reason); + + if (ack_reason > 0) { + rxrpc_send_ACK(call, ack_reason, ack_serial, + rxrpc_propose_ack_input_data); + } else { + call->ackr_nr_unacked++; + rxrpc_propose_delay_ACK(call, sp->hdr.serial, + rxrpc_propose_ack_input_data); + } if (notify) { trace_rxrpc_notify_socket(call->debug_id, sp->hdr.serial); rxrpc_notify_socket(call);