Return-Path: Received: from mail-it0-f67.google.com ([209.85.214.67]:34782 "EHLO mail-it0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752741AbcFNTEi (ORCPT ); Tue, 14 Jun 2016 15:04:38 -0400 Received: by mail-it0-f67.google.com with SMTP id d71so419355ith.1 for ; Tue, 14 Jun 2016 12:04:37 -0700 (PDT) From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH 3/5] SUNRPC: RPC transport queue must be low latency Date: Tue, 14 Jun 2016 15:04:04 -0400 Message-Id: <1465931046-30696-3-git-send-email-trond.myklebust@primarydata.com> In-Reply-To: <1465931046-30696-2-git-send-email-trond.myklebust@primarydata.com> References: <1465931046-30696-1-git-send-email-trond.myklebust@primarydata.com> <1465931046-30696-2-git-send-email-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: rpciod can easily get congested due to the long list of queued rpc_tasks. Having the receive queue wait in turn for those tasks to complete can therefore be a bottleneck. Address the problem by separating the workqueues into: - rpciod: manages rpc_tasks - xprtiod: manages transport related work. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/sched.h | 1 + net/sunrpc/sched.c | 24 ++++++++++++++++++++---- net/sunrpc/xprt.c | 8 ++++---- net/sunrpc/xprtsock.c | 6 +++--- 4 files changed, 28 insertions(+), 11 deletions(-) diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h index 05a1809c44d9..ef780b3b5e31 100644 --- a/include/linux/sunrpc/sched.h +++ b/include/linux/sunrpc/sched.h @@ -247,6 +247,7 @@ void rpc_show_tasks(struct net *); int rpc_init_mempool(void); void rpc_destroy_mempool(void); extern struct workqueue_struct *rpciod_workqueue; +extern struct workqueue_struct *xprtiod_workqueue; void rpc_prepare_task(struct rpc_task *task); static inline int rpc_wait_for_completion_task(struct rpc_task *task) diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index fcfd48d263f6..a9f786247ffb 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -54,7 +54,8 @@ static struct rpc_wait_queue delay_queue; /* * rpciod-related stuff */ -struct workqueue_struct *rpciod_workqueue; +struct workqueue_struct *rpciod_workqueue __read_mostly; +struct workqueue_struct *xprtiod_workqueue __read_mostly; /* * Disable the timer for a given RPC task. Should be called with @@ -1071,10 +1072,22 @@ static int rpciod_start(void) * Create the rpciod thread and wait for it to start. */ dprintk("RPC: creating workqueue rpciod\n"); - /* Note: highpri because network receive is latency sensitive */ - wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); + wq = alloc_workqueue("rpciod", WQ_MEM_RECLAIM, 0); + if (!wq) + goto out_failed; rpciod_workqueue = wq; - return rpciod_workqueue != NULL; + /* Note: highpri because network receive is latency sensitive */ + wq = alloc_workqueue("xprtiod", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); + if (!wq) + goto free_rpciod; + xprtiod_workqueue = wq; + return 1; +free_rpciod: + wq = rpciod_workqueue; + rpciod_workqueue = NULL; + destroy_workqueue(wq); +out_failed: + return 0; } static void rpciod_stop(void) @@ -1088,6 +1101,9 @@ static void rpciod_stop(void) wq = rpciod_workqueue; rpciod_workqueue = NULL; destroy_workqueue(wq); + wq = xprtiod_workqueue; + xprtiod_workqueue = NULL; + destroy_workqueue(wq); } void diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 216a1385718a..71df082b84a9 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -220,7 +220,7 @@ static void xprt_clear_locked(struct rpc_xprt *xprt) clear_bit(XPRT_LOCKED, &xprt->state); smp_mb__after_atomic(); } else - queue_work(rpciod_workqueue, &xprt->task_cleanup); + queue_work(xprtiod_workqueue, &xprt->task_cleanup); } /* @@ -645,7 +645,7 @@ void xprt_force_disconnect(struct rpc_xprt *xprt) set_bit(XPRT_CLOSE_WAIT, &xprt->state); /* Try to schedule an autoclose RPC call */ if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) - queue_work(rpciod_workqueue, &xprt->task_cleanup); + queue_work(xprtiod_workqueue, &xprt->task_cleanup); xprt_wake_pending_tasks(xprt, -EAGAIN); spin_unlock_bh(&xprt->transport_lock); } @@ -672,7 +672,7 @@ void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie) set_bit(XPRT_CLOSE_WAIT, &xprt->state); /* Try to schedule an autoclose RPC call */ if (test_and_set_bit(XPRT_LOCKED, &xprt->state) == 0) - queue_work(rpciod_workqueue, &xprt->task_cleanup); + queue_work(xprtiod_workqueue, &xprt->task_cleanup); xprt_wake_pending_tasks(xprt, -EAGAIN); out: spin_unlock_bh(&xprt->transport_lock); @@ -689,7 +689,7 @@ xprt_init_autodisconnect(unsigned long data) if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) goto out_abort; spin_unlock(&xprt->transport_lock); - queue_work(rpciod_workqueue, &xprt->task_cleanup); + queue_work(xprtiod_workqueue, &xprt->task_cleanup); return; out_abort: spin_unlock(&xprt->transport_lock); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 62b4f5a2a331..646170d0cb86 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1095,7 +1095,7 @@ static void xs_data_ready(struct sock *sk) if (xprt->reestablish_timeout) xprt->reestablish_timeout = 0; if (!test_and_set_bit(XPRT_SOCK_DATA_READY, &transport->sock_state)) - queue_work(rpciod_workqueue, &transport->recv_worker); + queue_work(xprtiod_workqueue, &transport->recv_worker); } read_unlock_bh(&sk->sk_callback_lock); } @@ -2378,7 +2378,7 @@ static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task) /* Start by resetting any existing state */ xs_reset_transport(transport); - queue_delayed_work(rpciod_workqueue, + queue_delayed_work(xprtiod_workqueue, &transport->connect_worker, xprt->reestablish_timeout); xprt->reestablish_timeout <<= 1; @@ -2388,7 +2388,7 @@ static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task) xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO; } else { dprintk("RPC: xs_connect scheduled xprt %p\n", xprt); - queue_delayed_work(rpciod_workqueue, + queue_delayed_work(xprtiod_workqueue, &transport->connect_worker, 0); } } -- 2.5.5