[lkml]   [2019]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 4.20 023/117] SUNRPC: Address Kerberos performance/behavior regression
4.20-stable review patch.  If anyone has any objections, please let me know.


[ Upstream commit deaa5c96c2f7e8b934088a1e70a0fe8797bd1149 ]

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 918f3c1fe83c ("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: 918f3c1fe83c ("SUNRPC: Improve latency for interactive ... ")
Signed-off-by: Chuck Lever <>
Signed-off-by: Anna Schumaker <>
Signed-off-by: Sasha Levin <>
Signed-off-by: Greg Kroah-Hartman <>
net/sunrpc/xprt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1177,7 +1177,7 @@ xprt_request_enqueue_transmit(struct rpc
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)

 \ /
  Last update: 2019-01-29 13:11    [W:0.446 / U:1.408 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site