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From: Trond Myklebust <trondmy@gmail.com>
To: linux-nfs@vger.kernel.org
Subject: [PATCH v2 26/34] SUNRPC: Improve latency for interactive tasks
Date: Tue,  4 Sep 2018 17:05:41 -0400	[thread overview]
Message-ID: <20180904210549.81673-27-trond.myklebust@hammerspace.com> (raw)
In-Reply-To: <20180904210549.81673-26-trond.myklebust@hammerspace.com>

One of the intentions with the priority queues was to ensure that no
single process can hog the transport. The field task->tk_owner therefore
identifies the RPC call's origin, and is intended to allow the RPC layer
to organise queues for fairness.
This commit therefore modifies the transmit queue to group requests
by task->tk_owner, and ensures that we round robin among those groups.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 include/linux/sunrpc/xprt.h       |  1 +
 net/sunrpc/backchannel_rqst.c     |  1 +
 net/sunrpc/xprt.c                 | 23 +++++++++++++++++++++--
 net/sunrpc/xprtrdma/backchannel.c |  1 +
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index b23c757bebfc..5dd64bdb28cd 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -89,6 +89,7 @@ struct rpc_rqst {
 	};
 
 	struct list_head	rq_xmit;	/* Send queue */
+	struct list_head	rq_xmit2;	/* Send queue */
 
 	void			*rq_buffer;	/* Call XDR encode buffer */
 	size_t			rq_callsize;
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 39b394b7dae3..e43dbab2e3f0 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -93,6 +93,7 @@ struct rpc_rqst *xprt_alloc_bc_req(struct rpc_xprt *xprt, gfp_t gfp_flags)
 	req->rq_xprt = xprt;
 	INIT_LIST_HEAD(&req->rq_recv);
 	INIT_LIST_HEAD(&req->rq_xmit);
+	INIT_LIST_HEAD(&req->rq_xmit2);
 	INIT_LIST_HEAD(&req->rq_bc_list);
 
 	/* Preallocate one XDR receive buffer */
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a7a93d61567f..8a4c5260eecd 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1043,6 +1043,7 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
 {
 	struct rpc_rqst *req = task->tk_rqstp;
 	struct rpc_xprt *xprt = req->rq_xprt;
+	struct rpc_rqst *pos;
 
 	spin_lock(&xprt->queue_lock);
 	if (list_empty(&req->rq_xmit) && xprt_request_need_transmit(task) &&
@@ -1052,7 +1053,6 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
 		 * to the head of the list to avoid starvation issues.
 		 */
 		if (req->rq_cong) {
-			struct rpc_rqst *pos;
 			list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) {
 				if (pos->rq_cong)
 					continue;
@@ -1060,6 +1060,13 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
 				list_add_tail(&req->rq_xmit, &pos->rq_xmit);
 				goto out;
 			}
+		} else {
+			list_for_each_entry(pos, &xprt->xmit_queue, rq_xmit) {
+				if (pos->rq_task->tk_owner != task->tk_owner)
+					continue;
+				list_add_tail(&req->rq_xmit2, &pos->rq_xmit2);
+				goto out;
+			}
 		}
 		list_add_tail(&req->rq_xmit, &xprt->xmit_queue);
 	}
@@ -1077,8 +1084,19 @@ xprt_request_enqueue_transmit(struct rpc_task *task)
 static void
 xprt_request_dequeue_transmit_locked(struct rpc_task *task)
 {
+	struct rpc_rqst *req = task->tk_rqstp;
+
 	clear_bit(RPC_TASK_NEED_XMIT, &task->tk_runstate);
-	list_del_init(&task->tk_rqstp->rq_xmit);
+	if (!list_empty(&req->rq_xmit)) {
+		list_del_init(&req->rq_xmit);
+		if (!list_empty(&req->rq_xmit2)) {
+			struct rpc_rqst *next = list_first_entry(&req->rq_xmit2,
+					struct rpc_rqst, rq_xmit2);
+			list_del_init(&req->rq_xmit2);
+			list_add_tail(&next->rq_xmit, &next->rq_xprt->xmit_queue);
+		}
+	} else if (!list_empty(&req->rq_xmit2))
+		list_del_init(&req->rq_xmit2);
 }
 
 /**
@@ -1376,6 +1394,7 @@ xprt_request_init(struct rpc_task *task)
 
 	INIT_LIST_HEAD(&req->rq_recv);
 	INIT_LIST_HEAD(&req->rq_xmit);
+	INIT_LIST_HEAD(&req->rq_xmit2);
 	req->rq_timeout = task->tk_client->cl_timeout->to_initval;
 	req->rq_task	= task;
 	req->rq_xprt    = xprt;
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index 14fc4596075e..92fffe765731 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -53,6 +53,7 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,
 		rqst->rq_xprt = xprt;
 		INIT_LIST_HEAD(&rqst->rq_recv);
 		INIT_LIST_HEAD(&rqst->rq_xmit);
+		INIT_LIST_HEAD(&rqst->rq_xmit2);
 		INIT_LIST_HEAD(&rqst->rq_bc_list);
 		__set_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
 		spin_lock_bh(&xprt->bc_pa_lock);
-- 
2.17.1

  reply	other threads:[~2018-09-05  1:33 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-04 21:05 [PATCH v2 00/34] Convert RPC client transmission to a queued model Trond Myklebust
2018-09-04 21:05 ` [PATCH v2 01/34] SUNRPC: Clean up initialisation of the struct rpc_rqst Trond Myklebust
2018-09-04 21:05   ` [PATCH v2 02/34] SUNRPC: If there is no reply expected, bail early from call_decode Trond Myklebust
2018-09-04 21:05     ` [PATCH v2 03/34] SUNRPC: The transmitted message must lie in the RPCSEC window of validity Trond Myklebust
2018-09-04 21:05       ` [PATCH v2 04/34] SUNRPC: Simplify identification of when the message send/receive is complete Trond Myklebust
2018-09-04 21:05         ` [PATCH v2 05/34] SUNRPC: Avoid holding locks across the XDR encoding of the RPC message Trond Myklebust
2018-09-04 21:05           ` [PATCH v2 06/34] SUNRPC: Rename TCP receive-specific state variables Trond Myklebust
2018-09-04 21:05             ` [PATCH v2 07/34] SUNRPC: Move reset of TCP state variables into the reconnect code Trond Myklebust
2018-09-04 21:05               ` [PATCH v2 08/34] SUNRPC: Add socket transmit queue offset tracking Trond Myklebust
2018-09-04 21:05                 ` [PATCH v2 09/34] SUNRPC: Simplify dealing with aborted partially transmitted messages Trond Myklebust
2018-09-04 21:05                   ` [PATCH v2 10/34] SUNRPC: Refactor the transport request pinning Trond Myklebust
2018-09-04 21:05                     ` [PATCH v2 11/34] SUNRPC: Add a helper to wake up a sleeping rpc_task and set its status Trond Myklebust
2018-09-04 21:05                       ` [PATCH v2 12/34] SUNRPC: Don't wake queued RPC calls multiple times in xprt_transmit Trond Myklebust
2018-09-04 21:05                         ` [PATCH v2 13/34] SUNRPC: Rename xprt->recv_lock to xprt->queue_lock Trond Myklebust
2018-09-04 21:05                           ` [PATCH v2 14/34] SUNRPC: Refactor xprt_transmit() to remove the reply queue code Trond Myklebust
2018-09-04 21:05                             ` [PATCH v2 15/34] SUNRPC: Refactor xprt_transmit() to remove wait for reply code Trond Myklebust
2018-09-04 21:05                               ` [PATCH v2 16/34] SUNRPC: Minor cleanup for call_transmit() Trond Myklebust
2018-09-04 21:05                                 ` [PATCH v2 17/34] SUNRPC: Distinguish between the slot allocation list and receive queue Trond Myklebust
2018-09-04 21:05                                   ` [PATCH v2 18/34] NFS: Add a transmission queue for RPC requests Trond Myklebust
2018-09-04 21:05                                     ` [PATCH v2 19/34] SUNRPC: Refactor RPC call encoding Trond Myklebust
2018-09-04 21:05                                       ` [PATCH v2 20/34] SUNRPC: Treat the task and request as separate in the xprt_ops->send_request() Trond Myklebust
2018-09-04 21:05                                         ` [PATCH v2 21/34] SUNRPC: Don't reset the request 'bytes_sent' counter when releasing XPRT_LOCK Trond Myklebust
2018-09-04 21:05                                           ` [PATCH v2 22/34] SUNRPC: Simplify xprt_prepare_transmit() Trond Myklebust
2018-09-04 21:05                                             ` [PATCH v2 23/34] SUNRPC: Move RPC retransmission stat counter to xprt_transmit() Trond Myklebust
2018-09-04 21:05                                               ` [PATCH v2 24/34] SUNRPC: Fix up the back channel transmit Trond Myklebust
2018-09-04 21:05                                                 ` [PATCH v2 25/34] SUNRPC: Support for congestion control when queuing is enabled Trond Myklebust
2018-09-04 21:05                                                   ` Trond Myklebust [this message]
2018-09-04 21:05                                                     ` [PATCH v2 27/34] SUNRPC: Allow calls to xprt_transmit() to drain the entire transmit queue Trond Myklebust
2018-09-04 21:05                                                       ` [PATCH v2 28/34] SUNRPC: Queue the request for transmission immediately after encoding Trond Myklebust
2018-09-04 21:05                                                         ` [PATCH v2 29/34] SUNRPC: Convert the xprt->sending queue back to an ordinary wait queue Trond Myklebust
2018-09-04 21:05                                                           ` [PATCH v2 30/34] SUNRPC: Allow soft RPC calls to time out when waiting for the XPRT_LOCK Trond Myklebust
2018-09-04 21:05                                                             ` [PATCH v2 31/34] SUNRPC: Turn off throttling of RPC slots for TCP sockets Trond Myklebust
2018-09-04 21:05                                                               ` [PATCH v2 32/34] SUNRPC: Clean up transport write space handling Trond Myklebust
2018-09-04 21:05                                                                 ` [PATCH v2 33/34] SUNRPC: Cleanup: remove the unused 'task' argument from the request_send() Trond Myklebust
2018-09-04 21:05                                                                   ` [PATCH v2 34/34] SUNRPC: Queue fairness for all Trond Myklebust
2018-09-06 14:17                                                           ` [PATCH v2 29/34] SUNRPC: Convert the xprt->sending queue back to an ordinary wait queue Schumaker, Anna
2018-09-06 14:23                                                             ` Schumaker, Anna
2018-09-06 14:23                                                             ` Schumaker, Anna
2018-09-05 14:30                                               ` [PATCH v2 23/34] SUNRPC: Move RPC retransmission stat counter to xprt_transmit() Chuck Lever
2018-09-05 15:28                                                 ` Trond Myklebust
2018-09-05 15:31                                                   ` Chuck Lever
2018-09-05 16:07                                                     ` Trond Myklebust
2018-09-05 16:34                                                       ` Chuck Lever
2018-09-06 18:49                                         ` [PATCH v2 20/34] SUNRPC: Treat the task and request as separate in the xprt_ops->send_request() Schumaker, Anna
2018-09-06 18:57                                           ` Trond Myklebust

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