From 31b3e5ce9f79d2a41808f53f38c5d590cebb2c73 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 2 Jan 2025 20:00:01 -0500 Subject: [PATCH] Revert "SUNRPC: Reduce thread wake-up rate when receiving large RPC messages" commit 966a675da844f1a764bb44557c21561cc3d09840 upstream. I noticed that a handful of NFSv3 fstests were taking an unexpectedly long time to run. Troubleshooting showed that the server's TCP window closed and never re-opened, which caused the client to trigger an RPC retransmit timeout after 180 seconds. The client's recovery action was to establish a fresh connection and retransmit the timed-out requests. This worked, but it adds a long delay. I tracked the problem to the commit that attempted to reduce the rate at which the network layer delivers TCP socket data_ready callbacks. Under most circumstances this change worked as expected, but for NFSv3, which has no session or other type of throttling, it can overwhelm the receiver on occasion. I'm sure I could tweak the lowat settings, but the small benefit doesn't seem worth the bother. Just revert it. Fixes: 2b877fc53e97 ("SUNRPC: Reduce thread wake-up rate when receiving large RPC messages") Cc: Jakub Kicinski Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/svcsock.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 59e2c46240f5..3bfbb789c4be 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1083,9 +1083,6 @@ static void svc_tcp_fragment_received(struct svc_sock *svsk) /* If we have more data, signal svc_xprt_enqueue() to try again */ svsk->sk_tcplen = 0; svsk->sk_marker = xdr_zero; - - smp_wmb(); - tcp_set_rcvlowat(svsk->sk_sk, 1); } /** @@ -1175,17 +1172,10 @@ err_incomplete: goto err_delete; if (len == want) svc_tcp_fragment_received(svsk); - else { - /* Avoid more ->sk_data_ready() calls until the rest - * of the message has arrived. This reduces service - * thread wake-ups on large incoming messages. */ - tcp_set_rcvlowat(svsk->sk_sk, - svc_sock_reclen(svsk) - svsk->sk_tcplen); - + else trace_svcsock_tcp_recv_short(&svsk->sk_xprt, svc_sock_reclen(svsk), svsk->sk_tcplen - sizeof(rpc_fraghdr)); - } goto err_noclose; error: if (len != -EAGAIN)