Return-Path: Received: from mail-it0-f68.google.com ([209.85.214.68]:36602 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752377AbdHPXAW (ORCPT ); Wed, 16 Aug 2017 19:00:22 -0400 Received: by mail-it0-f68.google.com with SMTP id o72so3274209ita.3 for ; Wed, 16 Aug 2017 16:00:21 -0700 (PDT) From: Trond Myklebust To: linux-nfs@vger.kernel.org Subject: [PATCH v3 5/5] SUNRPC: Add a separate spinlock to protect the RPC request receive list Date: Wed, 16 Aug 2017 19:00:08 -0400 Message-Id: <20170816230008.20006-6-trond.myklebust@primarydata.com> In-Reply-To: <20170816230008.20006-5-trond.myklebust@primarydata.com> References: <20170816230008.20006-1-trond.myklebust@primarydata.com> <20170816230008.20006-2-trond.myklebust@primarydata.com> <20170816230008.20006-3-trond.myklebust@primarydata.com> <20170816230008.20006-4-trond.myklebust@primarydata.com> <20170816230008.20006-5-trond.myklebust@primarydata.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: This further reduces contention with the transport_lock, and allows us to convert to using a non-bh-safe spinlock, since the list is now never accessed from a bh context. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 1 + net/sunrpc/xprt.c | 20 ++++++++++++-------- net/sunrpc/xprtrdma/rpc_rdma.c | 8 ++++---- net/sunrpc/xprtsock.c | 30 ++++++++++++++++-------------- 4 files changed, 33 insertions(+), 26 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 65b9e0224753..a97e6de5f9f2 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -232,6 +232,7 @@ struct rpc_xprt { */ spinlock_t transport_lock; /* lock transport info */ spinlock_t reserve_lock; /* lock slot table */ + spinlock_t recv_lock; /* lock receive list */ u32 xid; /* Next XID value to use */ struct rpc_task * snd_task; /* Task blocked in send */ struct svc_xprt *bc_xprt; /* NFSv4.1 backchannel */ diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 3eb9ec16eec4..2af189c5ac3e 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -872,17 +872,17 @@ void xprt_unpin_rqst(struct rpc_rqst *req) } static void xprt_wait_on_pinned_rqst(struct rpc_rqst *req) -__must_hold(&req->rq_xprt->transport_lock) +__must_hold(&req->rq_xprt->recv_lock) { struct rpc_task *task = req->rq_task; if (task && test_bit(RPC_TASK_MSG_RECV, &task->tk_runstate)) { - spin_unlock_bh(&req->rq_xprt->transport_lock); + spin_unlock(&req->rq_xprt->recv_lock); set_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate); wait_on_bit(&task->tk_runstate, RPC_TASK_MSG_RECV, TASK_UNINTERRUPTIBLE); clear_bit(RPC_TASK_MSG_RECV_WAIT, &task->tk_runstate); - spin_lock_bh(&req->rq_xprt->transport_lock); + spin_lock(&req->rq_xprt->recv_lock); } } @@ -1008,13 +1008,13 @@ void xprt_transmit(struct rpc_task *task) /* * Add to the list only if we're expecting a reply */ - spin_lock_bh(&xprt->transport_lock); /* Update the softirq receive buffer */ memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(req->rq_private_buf)); /* Add request to the receive list */ + spin_lock(&xprt->recv_lock); list_add_tail(&req->rq_list, &xprt->recv); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); xprt_reset_majortimeo(req); /* Turn off autodisconnect */ del_singleshot_timer_sync(&xprt->timer); @@ -1329,15 +1329,18 @@ void xprt_release(struct rpc_task *task) task->tk_ops->rpc_count_stats(task, task->tk_calldata); else if (task->tk_client) rpc_count_iostats(task, task->tk_client->cl_metrics); + spin_lock(&xprt->recv_lock); + if (!list_empty(&req->rq_list)) { + list_del(&req->rq_list); + xprt_wait_on_pinned_rqst(req); + } + spin_unlock(&xprt->recv_lock); spin_lock_bh(&xprt->transport_lock); xprt->ops->release_xprt(xprt, task); if (xprt->ops->release_request) xprt->ops->release_request(task); - if (!list_empty(&req->rq_list)) - list_del(&req->rq_list); xprt->last_used = jiffies; xprt_schedule_autodisconnect(xprt); - xprt_wait_on_pinned_rqst(req); spin_unlock_bh(&xprt->transport_lock); if (req->rq_buffer) xprt->ops->buf_free(task); @@ -1361,6 +1364,7 @@ static void xprt_init(struct rpc_xprt *xprt, struct net *net) spin_lock_init(&xprt->transport_lock); spin_lock_init(&xprt->reserve_lock); + spin_lock_init(&xprt->recv_lock); INIT_LIST_HEAD(&xprt->free); INIT_LIST_HEAD(&xprt->recv); diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index ca4d6e4528f3..dfa748a0c8de 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -1051,7 +1051,7 @@ rpcrdma_reply_handler(struct work_struct *work) * RPC completion while holding the transport lock to ensure * the rep, rqst, and rq_task pointers remain stable. */ - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); rqst = xprt_lookup_rqst(xprt, headerp->rm_xid); if (!rqst) goto out_norqst; @@ -1136,7 +1136,7 @@ rpcrdma_reply_handler(struct work_struct *work) xprt_release_rqst_cong(rqst->rq_task); xprt_complete_rqst(rqst->rq_task, status); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); dprintk("RPC: %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n", __func__, xprt, rqst, status); return; @@ -1187,12 +1187,12 @@ rpcrdma_reply_handler(struct work_struct *work) r_xprt->rx_stats.bad_reply_count++; goto out; -/* The req was still available, but by the time the transport_lock +/* The req was still available, but by the time the recv_lock * was acquired, the rqst and task had been released. Thus the RPC * has already been terminated. */ out_norqst: - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); rpcrdma_buffer_put(req); dprintk("RPC: %s: race, no rqst left for req %p\n", __func__, req); diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index a344bea15fc7..2b918137aaa0 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -969,12 +969,12 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt, return; /* Look up and lock the request corresponding to the given XID */ - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); rovr = xprt_lookup_rqst(xprt, *xp); if (!rovr) goto out_unlock; xprt_pin_rqst(rovr); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); task = rovr->rq_task; copied = rovr->rq_private_buf.buflen; @@ -983,16 +983,16 @@ static void xs_local_data_read_skb(struct rpc_xprt *xprt, if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) { dprintk("RPC: sk_buff copy failed\n"); - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); goto out_unpin; } - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); xprt_complete_rqst(task, copied); out_unpin: xprt_unpin_rqst(rovr); out_unlock: - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); } static void xs_local_data_receive(struct sock_xprt *transport) @@ -1055,12 +1055,12 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt, return; /* Look up and lock the request corresponding to the given XID */ - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); rovr = xprt_lookup_rqst(xprt, *xp); if (!rovr) goto out_unlock; xprt_pin_rqst(rovr); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); task = rovr->rq_task; if ((copied = rovr->rq_private_buf.buflen) > repsize) @@ -1069,7 +1069,7 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt, /* Suck it into the iovec, verify checksum if not done by hw. */ if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) { __UDPX_INC_STATS(sk, UDP_MIB_INERRORS); - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); goto out_unpin; } @@ -1077,11 +1077,13 @@ static void xs_udp_data_read_skb(struct rpc_xprt *xprt, spin_lock_bh(&xprt->transport_lock); xprt_adjust_cwnd(xprt, task, copied); + spin_unlock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); xprt_complete_rqst(task, copied); out_unpin: xprt_unpin_rqst(rovr); out_unlock: - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); } static void xs_udp_data_receive(struct sock_xprt *transport) @@ -1344,24 +1346,24 @@ static inline int xs_tcp_read_reply(struct rpc_xprt *xprt, dprintk("RPC: read reply XID %08x\n", ntohl(transport->tcp_xid)); /* Find and lock the request corresponding to this xid */ - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); req = xprt_lookup_rqst(xprt, transport->tcp_xid); if (!req) { dprintk("RPC: XID %08x request not found!\n", ntohl(transport->tcp_xid)); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); return -1; } xprt_pin_rqst(req); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); xs_tcp_read_common(xprt, desc, req); - spin_lock_bh(&xprt->transport_lock); + spin_lock(&xprt->recv_lock); if (!(transport->tcp_flags & TCP_RCV_COPY_DATA)) xprt_complete_rqst(req->rq_task, transport->tcp_copied); xprt_unpin_rqst(req); - spin_unlock_bh(&xprt->transport_lock); + spin_unlock(&xprt->recv_lock); return 0; } -- 2.13.5