From patchwork Wed May 26 04:27:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Trond Myklebust X-Patchwork-Id: 12280581 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D4F8C2B9F7 for ; Wed, 26 May 2021 04:28:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0BE3D61402 for ; Wed, 26 May 2021 04:28:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229553AbhEZE33 (ORCPT ); Wed, 26 May 2021 00:29:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:34644 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229523AbhEZE33 (ORCPT ); Wed, 26 May 2021 00:29:29 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 605A661402 for ; Wed, 26 May 2021 04:27:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622003278; bh=Q9oUQP1vJGel5PqVddm5L3PF/MjzKGmTdbZekTT1Hok=; h=From:To:Subject:Date:From; b=h2rt9dRILn57ZaSLrE23pyzq3iOUKGX0D+xa0A57Lqoc4tLz/uCjJF/gdrBbj1Vm1 uVbze4Fzx2AVRkBbjRVUz64QTYr9fH9H1WGo628Pw5p/D3Nnx+9n34greF/sRV5wPt cFzpqP/FYb75DQ8Se0VSNvgi+P+TQh4uSLAQCX/Dp3yOE755cpz1pAGTdb80SOoIUX IuuSop+rJc5iEUG0OOUSY6xKOj1qBD0XSZBZ/pP74KMdrM9HFJIMqcA9vfv2AOdI2e 4o556t6oBvjLEiVm/NQTxmzx6YfC6ahs5IjU5XAw1wAC1/iUioCDoG/yQAn5pgxeVT Lhj59oUB1QrfA== From: trondmy@kernel.org To: linux-nfs@vger.kernel.org Subject: [PATCH] SUNRPC: More fixes for backlog congestion Date: Wed, 26 May 2021 00:27:57 -0400 Message-Id: <20210526042757.333605-1-trondmy@kernel.org> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: Trond Myklebust Ensure that we fix the XPRT_CONGESTED starvation issue for RDMA as well as socket based transports. Ensure we always initialise the request after waking up from the backlog list. Fixes: e877a88d1f06 ("SUNRPC in case of backlog, hand free slots directly to waiting task") Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 2 ++ net/sunrpc/xprt.c | 58 ++++++++++++++++----------------- net/sunrpc/xprtrdma/transport.c | 6 ++-- 3 files changed, 32 insertions(+), 34 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index d81fe8b364d0..61b622e334ee 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -368,6 +368,8 @@ struct rpc_xprt * xprt_alloc(struct net *net, size_t size, unsigned int num_prealloc, unsigned int max_req); void xprt_free(struct rpc_xprt *); +void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task); +bool xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req); static inline int xprt_enable_swap(struct rpc_xprt *xprt) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 5b3981fd3783..3509a7f139b9 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1607,11 +1607,18 @@ xprt_transmit(struct rpc_task *task) spin_unlock(&xprt->queue_lock); } -static void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task) +static void xprt_complete_request_init(struct rpc_task *task) +{ + if (task->tk_rqstp) + xprt_request_init(task); +} + +void xprt_add_backlog(struct rpc_xprt *xprt, struct rpc_task *task) { set_bit(XPRT_CONGESTED, &xprt->state); - rpc_sleep_on(&xprt->backlog, task, NULL); + rpc_sleep_on(&xprt->backlog, task, xprt_complete_request_init); } +EXPORT_SYMBOL_GPL(xprt_add_backlog); static bool __xprt_set_rq(struct rpc_task *task, void *data) { @@ -1619,14 +1626,13 @@ static bool __xprt_set_rq(struct rpc_task *task, void *data) if (task->tk_rqstp == NULL) { memset(req, 0, sizeof(*req)); /* mark unused */ - task->tk_status = -EAGAIN; task->tk_rqstp = req; return true; } return false; } -static bool xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req) +bool xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req) { if (rpc_wake_up_first(&xprt->backlog, __xprt_set_rq, req) == NULL) { clear_bit(XPRT_CONGESTED, &xprt->state); @@ -1634,6 +1640,7 @@ static bool xprt_wake_up_backlog(struct rpc_xprt *xprt, struct rpc_rqst *req) } return true; } +EXPORT_SYMBOL_GPL(xprt_wake_up_backlog); static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task) { @@ -1643,7 +1650,7 @@ static bool xprt_throttle_congested(struct rpc_xprt *xprt, struct rpc_task *task goto out; spin_lock(&xprt->reserve_lock); if (test_bit(XPRT_CONGESTED, &xprt->state)) { - rpc_sleep_on(&xprt->backlog, task, NULL); + xprt_add_backlog(xprt, task); ret = true; } spin_unlock(&xprt->reserve_lock); @@ -1812,10 +1819,6 @@ xprt_request_init(struct rpc_task *task) struct rpc_xprt *xprt = task->tk_xprt; struct rpc_rqst *req = task->tk_rqstp; - if (req->rq_task) - /* Already initialized */ - return; - req->rq_task = task; req->rq_xprt = xprt; req->rq_buffer = NULL; @@ -1876,10 +1879,8 @@ void xprt_retry_reserve(struct rpc_task *task) struct rpc_xprt *xprt = task->tk_xprt; task->tk_status = 0; - if (task->tk_rqstp != NULL) { - xprt_request_init(task); + if (task->tk_rqstp != NULL) return; - } task->tk_status = -EAGAIN; xprt_do_reserve(xprt, task); @@ -1904,24 +1905,21 @@ void xprt_release(struct rpc_task *task) } xprt = req->rq_xprt; - if (xprt) { - xprt_request_dequeue_xprt(task); - spin_lock(&xprt->transport_lock); - xprt->ops->release_xprt(xprt, task); - if (xprt->ops->release_request) - xprt->ops->release_request(task); - xprt_schedule_autodisconnect(xprt); - spin_unlock(&xprt->transport_lock); - if (req->rq_buffer) - xprt->ops->buf_free(task); - xdr_free_bvec(&req->rq_rcv_buf); - xdr_free_bvec(&req->rq_snd_buf); - if (req->rq_cred != NULL) - put_rpccred(req->rq_cred); - if (req->rq_release_snd_buf) - req->rq_release_snd_buf(req); - } else - xprt = task->tk_xprt; + xprt_request_dequeue_xprt(task); + spin_lock(&xprt->transport_lock); + xprt->ops->release_xprt(xprt, task); + if (xprt->ops->release_request) + xprt->ops->release_request(task); + xprt_schedule_autodisconnect(xprt); + spin_unlock(&xprt->transport_lock); + if (req->rq_buffer) + xprt->ops->buf_free(task); + xdr_free_bvec(&req->rq_rcv_buf); + xdr_free_bvec(&req->rq_snd_buf); + if (req->rq_cred != NULL) + put_rpccred(req->rq_cred); + if (req->rq_release_snd_buf) + req->rq_release_snd_buf(req); task->tk_rqstp = NULL; if (likely(!bc_prealloc(req))) diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 09953597d055..4a8f92ef99ae 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -520,9 +520,8 @@ xprt_rdma_alloc_slot(struct rpc_xprt *xprt, struct rpc_task *task) return; out_sleep: - set_bit(XPRT_CONGESTED, &xprt->state); - rpc_sleep_on(&xprt->backlog, task, NULL); task->tk_status = -EAGAIN; + xprt_add_backlog(xprt, task); } /** @@ -539,8 +538,7 @@ xprt_rdma_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *rqst) memset(rqst, 0, sizeof(*rqst)); rpcrdma_buffer_put(&r_xprt->rx_buf, rpcr_to_rdmar(rqst)); - if (unlikely(!rpc_wake_up_next(&xprt->backlog))) - clear_bit(XPRT_CONGESTED, &xprt->state); + xprt_wake_up_backlog(xprt, rqst); } static bool rpcrdma_check_regbuf(struct rpcrdma_xprt *r_xprt,