From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, 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 26524C73C70 for ; Wed, 10 Jul 2019 05:33:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5BB620665 for ; Wed, 10 Jul 2019 05:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="szFuctmf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727148AbfGJFdW (ORCPT ); Wed, 10 Jul 2019 01:33:22 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:49158 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727089AbfGJFdP (ORCPT ); Wed, 10 Jul 2019 01:33:15 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6A5SweC016908; Wed, 10 Jul 2019 05:33:09 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2018-07-02; bh=w6FK4Bahgy7fMBI7ZAjTSDt9NWIBZ1xoNSvpaVY8DFE=; b=szFuctmfrxjYYrWWg4FBp7tHbglgeOjWo5zw2gyf278/knFm/+MbWfqSPYph2W2ayxR0 kffYp4RTnsQ542LM3x7JMOoXlDVloqXzKeocrS0nK/2sayhf71M8wiSqTIRXL+JAf/17 OKIPKXuQ8S//88y2pbjWE1axkDY8s/9GmDMIDFqPQBbx1J9yNjiSvV0sgUQeGZxMy+fa HRexbxJPC6kfnOvIKaFTLJcV/NTuGLy/tRDoyg1uoc86Xl2QE2v8cecdWPMa+10G5WcN yyPCSaxg3QWsukOqMJd6GI13x7lAVp0mq9dpDRMcOtcCIrp4LeJIqidjR+c3YmoWuDcm Eg== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2tjk2tqxf3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jul 2019 05:33:09 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x6A5X9jo157323; Wed, 10 Jul 2019 05:33:09 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2tn1j0nw33-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 10 Jul 2019 05:33:08 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x6A5X7Hh009416; Wed, 10 Jul 2019 05:33:07 GMT Received: from localhost.localdomain (/10.159.154.151) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 09 Jul 2019 22:33:07 -0700 From: Santosh Shilimkar To: netdev@vger.kernel.org, davem@davemloft.net Cc: santosh.shilimkar@oracle.com Subject: [net][PATCH 2/5] Revert "RDS: IB: split the mr registration and invalidation path" Date: Tue, 9 Jul 2019 22:32:41 -0700 Message-Id: <1562736764-31752-3-git-send-email-santosh.shilimkar@oracle.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1562736764-31752-1-git-send-email-santosh.shilimkar@oracle.com> References: <1562736764-31752-1-git-send-email-santosh.shilimkar@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9313 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=975 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907100067 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9313 signatures=668688 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907100066 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Gerd Rausch This reverts commit 56012459310a1dbcc55c2dbf5500a9f7571402cb. RDS kept spinning inside function "rds_ib_post_reg_frmr", waiting for "i_fastreg_wrs" to become incremented: while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) { atomic_inc(&ibmr->ic->i_fastreg_wrs); cpu_relax(); } Looking at the original commit: commit 56012459310a ("RDS: IB: split the mr registration and invalidation path") In there, the "rds_ib_mr_cqe_handler" was changed in the following way: void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) if (frmr->fr_inv) { frmr->fr_state = FRMR_IS_FREE; frmr->fr_inv = false; atomic_inc(&ic->i_fastreg_wrs); } else { atomic_inc(&ic->i_fastunreg_wrs); } It looks like it's got it exactly backwards: Function "rds_ib_post_reg_frmr" keeps track of the outstanding requests via "i_fastreg_wrs". Function "rds_ib_post_inv" keeps track of the outstanding requests via "i_fastunreg_wrs" (post original commit). It also sets: frmr->fr_inv = true; However the completion handler "rds_ib_mr_cqe_handler" adjusts "i_fastreg_wrs" when "fr_inv" had been true, and adjusts "i_fastunreg_wrs" otherwise. The original commit was done in the name of performance: to remove the performance bottleneck No performance benefit could be observed with a fixed-up version of the original commit measured between two Oracle X7 servers, both equipped with Mellanox Connect-X5 HCAs. The prudent course of action is to revert this commit. Signed-off-by: Gerd Rausch Signed-off-by: Santosh Shilimkar --- net/rds/ib.h | 4 +--- net/rds/ib_cm.c | 9 ++------- net/rds/ib_frmr.c | 11 +++++------ 3 files changed, 8 insertions(+), 16 deletions(-) diff --git a/net/rds/ib.h b/net/rds/ib.h index 67a715b..66c03c7 100644 --- a/net/rds/ib.h +++ b/net/rds/ib.h @@ -15,8 +15,7 @@ #define RDS_IB_DEFAULT_RECV_WR 1024 #define RDS_IB_DEFAULT_SEND_WR 256 -#define RDS_IB_DEFAULT_FR_WR 256 -#define RDS_IB_DEFAULT_FR_INV_WR 256 +#define RDS_IB_DEFAULT_FR_WR 512 #define RDS_IB_DEFAULT_RETRY_COUNT 1 @@ -157,7 +156,6 @@ struct rds_ib_connection { /* To control the number of wrs from fastreg */ atomic_t i_fastreg_wrs; - atomic_t i_fastunreg_wrs; /* interrupt handling */ struct tasklet_struct i_send_tasklet; diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c index 66c6eb5..8891822 100644 --- a/net/rds/ib_cm.c +++ b/net/rds/ib_cm.c @@ -460,10 +460,7 @@ static int rds_ib_setup_qp(struct rds_connection *conn) * completion queue and send queue. This extra space is used for FRMR * registration and invalidation work requests */ - fr_queue_space = rds_ibdev->use_fastreg ? - (RDS_IB_DEFAULT_FR_WR + 1) + - (RDS_IB_DEFAULT_FR_INV_WR + 1) - : 0; + fr_queue_space = (rds_ibdev->use_fastreg ? RDS_IB_DEFAULT_FR_WR : 0); /* add the conn now so that connection establishment has the dev */ rds_ib_add_conn(rds_ibdev, conn); @@ -530,7 +527,6 @@ static int rds_ib_setup_qp(struct rds_connection *conn) attr.send_cq = ic->i_send_cq; attr.recv_cq = ic->i_recv_cq; atomic_set(&ic->i_fastreg_wrs, RDS_IB_DEFAULT_FR_WR); - atomic_set(&ic->i_fastunreg_wrs, RDS_IB_DEFAULT_FR_INV_WR); /* * XXX this can fail if max_*_wr is too large? Are we supposed @@ -1009,8 +1005,7 @@ void rds_ib_conn_path_shutdown(struct rds_conn_path *cp) wait_event(rds_ib_ring_empty_wait, rds_ib_ring_empty(&ic->i_recv_ring) && (atomic_read(&ic->i_signaled_sends) == 0) && - (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR) && - (atomic_read(&ic->i_fastunreg_wrs) == RDS_IB_DEFAULT_FR_INV_WR)); + (atomic_read(&ic->i_fastreg_wrs) == RDS_IB_DEFAULT_FR_WR)); tasklet_kill(&ic->i_send_tasklet); tasklet_kill(&ic->i_recv_tasklet); diff --git a/net/rds/ib_frmr.c b/net/rds/ib_frmr.c index 688dcd6..32ae26e 100644 --- a/net/rds/ib_frmr.c +++ b/net/rds/ib_frmr.c @@ -239,8 +239,8 @@ static int rds_ib_post_inv(struct rds_ib_mr *ibmr) if (frmr->fr_state != FRMR_IS_INUSE) goto out; - while (atomic_dec_return(&ibmr->ic->i_fastunreg_wrs) <= 0) { - atomic_inc(&ibmr->ic->i_fastunreg_wrs); + while (atomic_dec_return(&ibmr->ic->i_fastreg_wrs) <= 0) { + atomic_inc(&ibmr->ic->i_fastreg_wrs); cpu_relax(); } @@ -257,7 +257,7 @@ static int rds_ib_post_inv(struct rds_ib_mr *ibmr) if (unlikely(ret)) { frmr->fr_state = FRMR_IS_STALE; frmr->fr_inv = false; - atomic_inc(&ibmr->ic->i_fastunreg_wrs); + atomic_inc(&ibmr->ic->i_fastreg_wrs); pr_err("RDS/IB: %s returned error(%d)\n", __func__, ret); goto out; } @@ -285,10 +285,9 @@ void rds_ib_mr_cqe_handler(struct rds_ib_connection *ic, struct ib_wc *wc) if (frmr->fr_inv) { frmr->fr_state = FRMR_IS_FREE; frmr->fr_inv = false; - atomic_inc(&ic->i_fastreg_wrs); - } else { - atomic_inc(&ic->i_fastunreg_wrs); } + + atomic_inc(&ic->i_fastreg_wrs); } void rds_ib_unreg_frmr(struct list_head *list, unsigned int *nfreed, -- 1.9.1