From patchwork Wed Feb 15 16:18:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Gu X-Patchwork-Id: 13141902 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE7B4C636D7 for ; Wed, 15 Feb 2023 16:19:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230099AbjBOQTY (ORCPT ); Wed, 15 Feb 2023 11:19:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57334 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230048AbjBOQS7 (ORCPT ); Wed, 15 Feb 2023 11:18:59 -0500 Received: from out30-99.freemail.mail.aliyun.com (out30-99.freemail.mail.aliyun.com [115.124.30.99]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 33F6F3B0CE; Wed, 15 Feb 2023 08:18:52 -0800 (PST) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R811e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=guwen@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0Vbl04yG_1676477927; Received: from localhost(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0Vbl04yG_1676477927) by smtp.aliyun-inc.com; Thu, 16 Feb 2023 00:18:49 +0800 From: Wen Gu To: kgraul@linux.ibm.com, wenjia@linux.ibm.com, jaka@linux.ibm.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH net-next v3 8/9] net/smc: Modify cursor update logic when using mappable DMB Date: Thu, 16 Feb 2023 00:18:24 +0800 Message-Id: <1676477905-88043-9-git-send-email-guwen@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1676477905-88043-1-git-send-email-guwen@linux.alibaba.com> References: <1676477905-88043-1-git-send-email-guwen@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Since local sndbuf shares the same physical memory region with peer RMB when using mappable DMBs, the cursor update logic needs to be adapted. The main concern is to ensure that the data written by local to this memory region won't overwrite the data that has not been consumed by the peer. So in this scene, the fin_curs and sndbuf_space that were originally updated when sending out CDC message are not updated until the cons_curs update from the peer is received. Signed-off-by: Wen Gu --- net/smc/smc_cdc.c | 50 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 11 deletions(-) diff --git a/net/smc/smc_cdc.c b/net/smc/smc_cdc.c index 9023684..74fcd2f 100644 --- a/net/smc/smc_cdc.c +++ b/net/smc/smc_cdc.c @@ -18,6 +18,7 @@ #include "smc_tx.h" #include "smc_rx.h" #include "smc_close.h" +#include "smc_ism.h" /********************************** send *************************************/ @@ -253,17 +254,24 @@ int smcd_cdc_msg_send(struct smc_connection *conn) return rc; smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn); conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0; - /* Calculate transmitted data and increment free send buffer space */ - diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, - &conn->tx_curs_sent); - /* increased by confirmed number of bytes */ - smp_mb__before_atomic(); - atomic_add(diff, &conn->sndbuf_space); - /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ - smp_mb__after_atomic(); - smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn); + if (!smc_ism_dmb_mappable(conn->lgr->smcd)) { + /* If local sndbuf has been mapped to peer RMB, then + * don't update the tx_curs_fin and sndbuf_space until + * peer has consumed the data in RMB. + */ - smc_tx_sndbuf_nonfull(smc); + /* Calculate transmitted data and increment free send buffer space */ + diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, + &conn->tx_curs_sent); + /* increased by confirmed number of bytes */ + smp_mb__before_atomic(); + atomic_add(diff, &conn->sndbuf_space); + /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ + smp_mb__after_atomic(); + smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn); + + smc_tx_sndbuf_nonfull(smc); + } return rc; } @@ -321,7 +329,7 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, { union smc_host_cursor cons_old, prod_old; struct smc_connection *conn = &smc->conn; - int diff_cons, diff_prod; + int diff_cons, diff_prod, diff_tx; smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn); smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn); @@ -337,6 +345,26 @@ static void smc_cdc_msg_recv_action(struct smc_sock *smc, atomic_add(diff_cons, &conn->peer_rmbe_space); /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */ smp_mb__after_atomic(); + + if (conn->lgr->is_smcd && + smc_ism_dmb_mappable(conn->lgr->smcd)) { + /* If local sndbuf has been mapped to peer RMB, then + * update tx_curs_fin and sndbuf_space when peer has + * consumed the data in it's RMB. + */ + + /* calculate peer rmb consumed data */ + diff_tx = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin, + &conn->local_rx_ctrl.cons); + /* increase local sndbuf space and fin_curs */ + smp_mb__before_atomic(); + atomic_add(diff_tx, &conn->sndbuf_space); + /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */ + smp_mb__after_atomic(); + smc_curs_copy(&conn->tx_curs_fin, &conn->local_rx_ctrl.cons, conn); + + smc_tx_sndbuf_nonfull(smc); + } } diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,