From: David Howells <dhowells@redhat.com>
To: netdev@vger.kernel.org
Cc: dhowells@redhat.com, linux-afs@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH net 3/3] rxrpc: Fix afs large storage transmission performance drop
Date: Thu, 18 Jun 2020 08:50:35 +0100 [thread overview]
Message-ID: <159246663560.1229328.1476552302291944463.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <159246661514.1229328.4419873299996950969.stgit@warthog.procyon.org.uk>
Commit 2ad6691d988c, which moved the modification of the status annotation
for a packet in the Tx buffer prior to the retransmission moved the state
clearance, but managed to lose the bit that set it to UNACK.
Consequently, if a retransmission occurs, the packet is accidentally
changed to the ACK state (ie. 0) by masking it off, which means that the
packet isn't counted towards the tally of newly-ACK'd packets if it gets
hard-ACK'd. This then prevents the congestion control algorithm from
recovering properly.
Fix by reinstating the change of state to UNACK.
Spotted by the generic/460 xfstest.
Fixes: 2ad6691d988c ("rxrpc: Fix race between incoming ACK parser and retransmitter")
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/call_event.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index aa1c8eee6557..6be2672a65ea 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -253,7 +253,7 @@ static void rxrpc_resend(struct rxrpc_call *call, unsigned long now_j)
* confuse things
*/
annotation &= ~RXRPC_TX_ANNO_MASK;
- annotation |= RXRPC_TX_ANNO_RESENT;
+ annotation |= RXRPC_TX_ANNO_UNACK | RXRPC_TX_ANNO_RESENT;
call->rxtx_annotations[ix] = annotation;
skb = call->rxtx_buffer[ix];
next prev parent reply other threads:[~2020-06-18 7:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-18 7:50 [PATCH net 0/3] rxrpc: Performance drop fix and other fixes David Howells
2020-06-18 7:50 ` [PATCH net 1/3] rxrpc: Fix trace string David Howells
2020-06-18 7:50 ` [PATCH net 2/3] rxrpc: Fix handling of rwind from an ACK packet David Howells
2020-06-18 7:50 ` David Howells [this message]
2020-06-20 2:57 ` [PATCH net 0/3] rxrpc: Performance drop fix and other fixes David Miller
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