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[68.40.189.247]) by smtp.gmail.com with ESMTPSA id r65sm3278223itb.19.2019.03.07.16.47.30 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 07 Mar 2019 16:47:31 -0800 (PST) From: Trond Myklebust X-Google-Original-From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH v3 1/3] SUNRPC: Prevent thundering herd when the socket is not connected Date: Thu, 7 Mar 2019 19:46:21 -0500 Message-Id: <20190308004623.10618-1-trond.myklebust@hammerspace.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If the socket is not connected, then we want to initiate a reconnect rather that trying to transmit requests. If there is a large number of requests queued and waiting for the lock in call_transmit(), then it can take a while for one of the to loop back and retake the lock in call_connect. Fixes: 89f90fe1ad8b ("SUNRPC: Allow calls to xprt_transmit() to drain...") Signed-off-by: Trond Myklebust --- net/sunrpc/clnt.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 241e8423fd0c..7ab4da342ab5 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -1807,7 +1807,12 @@ call_encode(struct rpc_task *task) xprt_request_enqueue_receive(task); xprt_request_enqueue_transmit(task); out: - task->tk_action = call_bind; + task->tk_action = call_transmit; + /* Check that the connection is OK */ + if (!xprt_bound(task->tk_xprt)) + task->tk_action = call_bind; + else if (!xprt_connected(task->tk_xprt)) + task->tk_action = call_connect; } /* @@ -1999,13 +2004,19 @@ call_transmit(struct rpc_task *task) { dprint_status(task); - task->tk_status = 0; + task->tk_action = call_transmit_status; if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) { if (!xprt_prepare_transmit(task)) return; - xprt_transmit(task); + task->tk_status = 0; + if (test_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate)) { + if (!xprt_connected(task->tk_xprt)) { + task->tk_status = -ENOTCONN; + return; + } + xprt_transmit(task); + } } - task->tk_action = call_transmit_status; xprt_end_transmit(task); } @@ -2067,6 +2078,8 @@ call_transmit_status(struct rpc_task *task) case -EADDRINUSE: case -ENOTCONN: case -EPIPE: + task->tk_action = call_bind; + task->tk_status = 0; break; } }