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| author | David Howells <dhowells@redhat.com> | 2024-12-04 07:46:41 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-12-09 13:48:26 -0800 |
| commit | 9e3cccd176b5ec6ff78693287fb03097e453e69c (patch) | |
| tree | b68272839cee48dca39bbfeaee3f4ea0f60065a6 /net/rxrpc/ar-internal.h | |
| parent | 149d002bee706f51772bd320cda90c922844bb0e (diff) | |
| download | linux-next-9e3cccd176b5ec6ff78693287fb03097e453e69c.tar.gz linux-next-9e3cccd176b5ec6ff78693287fb03097e453e69c.zip | |
rxrpc: Fix CPU time starvation in I/O thread
Starvation can happen in the rxrpc I/O thread because it goes back to the
top of the I/O loop after it does any one thing without trying to give any
other connection or call CPU time. Also, because it processes one call
packet at a time, it tries to do the retransmission loop after each ACK
without checking to see if there are other ACKs already in the queue that
can update the SACK state.
Fix this by:
(1) Add a received-packet queue on each call.
(2) Distribute packets from the master Rx queue to the individual call,
conn and error queues and 'poking' calls to add them to the attend
queue first thing in the I/O thread.
(3) Go through all the attention-seeking connections and calls before
going back to the top of the I/O thread. Each queue is extracted as a
whole and then gone through so that new additions to insert themselves
into the queue.
(4) Make the call event handler go through all the packets currently on
the call's rx_queue before transmitting and retransmitting DATA
packets.
(5) Drop the skb argument from the call event handler as this is now
replaced with the rx_queue. Instead, keep track of whether we
received a packet or an ACK for the tests that used to rely on that.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: https://patch.msgid.link/20241204074710.990092-14-dhowells@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/rxrpc/ar-internal.h')
| -rw-r--r-- | net/rxrpc/ar-internal.h | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h index 4386b2e6cca5..55cc68dd1b40 100644 --- a/net/rxrpc/ar-internal.h +++ b/net/rxrpc/ar-internal.h @@ -705,6 +705,7 @@ struct rxrpc_call { /* Received data tracking */ struct sk_buff_head recvmsg_queue; /* Queue of packets ready for recvmsg() */ + struct sk_buff_head rx_queue; /* Queue of packets for this call to receive */ struct sk_buff_head rx_oos_queue; /* Queue of out of sequence packets */ rxrpc_seq_t rx_highest_seq; /* Higest sequence number received */ @@ -906,7 +907,7 @@ void rxrpc_propose_delay_ACK(struct rxrpc_call *, rxrpc_serial_t, void rxrpc_shrink_call_tx_buffer(struct rxrpc_call *); void rxrpc_resend(struct rxrpc_call *call, struct sk_buff *ack_skb); -bool rxrpc_input_call_event(struct rxrpc_call *call, struct sk_buff *skb); +bool rxrpc_input_call_event(struct rxrpc_call *call); /* * call_object.c @@ -1352,6 +1353,13 @@ static inline bool after_eq(u32 seq1, u32 seq2) return (s32)(seq1 - seq2) >= 0; } +static inline void rxrpc_queue_rx_call_packet(struct rxrpc_call *call, struct sk_buff *skb) +{ + rxrpc_get_skb(skb, rxrpc_skb_get_call_rx); + __skb_queue_tail(&call->rx_queue, skb); + rxrpc_poke_call(call, rxrpc_call_poke_rx_packet); +} + /* * debug tracing */ |