From a66c2b38fd284d6a3bcf696acd35a519779b269a Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Wed, 9 Jan 2019 10:04:57 -0500 Subject: [PATCH] SUNRPC: Address Kerberos performance/behavior regression When using Kerberos with v4.20, I've observed frequent connection loss on heavy workloads. I traced it down to the client underrunning the GSS sequence number window -- NFS servers are required to drop the RPC with the low sequence number, and also drop the connection to signal that an RPC was dropped. Bisected to commit fab58f7c5458 ("SUNRPC: Improve latency for interactive tasks"). I've got a one-line workaround for this issue, which is easy to backport to v4.20 while a more permanent solution is being derived. Essentially, tk_owner-based sorting is disabled for RPCs that carry a GSS sequence number. Fixes: fab58f7c5458 ("SUNRPC: Improve latency for interactive ... ") Signed-off-by: Chuck Lever Signed-off-by: Anna Schumaker --- net/sunrpc/xprt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 9075ae150ae56..f1ec2110efebe 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1178,7 +1178,7 @@ xprt_request_enqueue_transmit(struct rpc_task *task) INIT_LIST_HEAD(&req->rq_xmit2); goto out; } - } else { + } else if (!req->rq_seqno) { list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) { if (pos->rq_task->tk_owner != task->tk_owner) continue; -- 2.39.5