From patchwork Thu Jul 14 09:43:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Gu X-Patchwork-Id: 12917619 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 1CB1ACCA480 for ; Thu, 14 Jul 2022 09:44:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238245AbiGNJoV (ORCPT ); Thu, 14 Jul 2022 05:44:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229897AbiGNJoU (ORCPT ); Thu, 14 Jul 2022 05:44:20 -0400 Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB47C11C1A; Thu, 14 Jul 2022 02:44:17 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=guwen@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0VJImA7W_1657791845; Received: from localhost(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0VJImA7W_1657791845) by smtp.aliyun-inc.com; Thu, 14 Jul 2022 17:44:14 +0800 From: Wen Gu To: kgraul@linux.ibm.com, wenjia@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-rdma@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net-next v2 0/6] net/smc: Introduce virtually contiguous buffers for SMC-R Date: Thu, 14 Jul 2022 17:43:59 +0800 Message-Id: <1657791845-1060-1-git-send-email-guwen@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org On long-running enterprise production servers, high-order contiguous memory pages are usually very rare and in most cases we can only get fragmented pages. When replacing TCP with SMC-R in such production scenarios, attempting to allocate high-order physically contiguous sndbufs and RMBs may result in frequent memory compaction, which will cause unexpected hung issue and further stability risks. So this patch set is aimed to allow SMC-R link group to use virtually contiguous sndbufs and RMBs to avoid potential issues mentioned above. Whether to use physically or virtually contiguous buffers can be set by sysctl smcr_buf_type. Note that using virtually contiguous buffers will bring an acceptable performance regression, which can be mainly divided into two parts: 1) regression in data path, which is brought by additional address translation of sndbuf by RNIC in Tx. But in general, translating address through MTT is fast. According to qperf test, this part regression is basically less than 10% in latency and bandwidth. (see patch 5/6 for details) 2) regression in buffer initialization and destruction path, which is brought by additional MR operations of sndbufs. But thanks to link group buffer reuse mechanism, the impact of this kind of regression decreases as times of buffer reuse increases. Patch set overview: - Patch 1/6 and 2/6 mainly about simplifying and optimizing DMA sync operation, which will reduce overhead on the data path, especially when using virtually contiguous buffers; - Patch 3/6 and 4/6 introduce a sysctl smcr_buf_type to set the type of buffers in new created link group; - Patch 5/6 allows SMC-R to use virtually contiguous sndbufs and RMBs, including buffer creation, destruction, MR operation and access; - patch 6/6 extends netlink attribute for buffer type of SMC-R link group; v1->v2: - Patch 5/6 fixes build issue on 32bit; - Patch 3/6 adds description of new sysctl in smc-sysctl.rst; Guangguan Wang (2): net/smc: remove redundant dma sync ops net/smc: optimize for smc_sndbuf_sync_sg_for_device and smc_rmb_sync_sg_for_cpu Wen Gu (4): net/smc: Introduce a sysctl for setting SMC-R buffer type net/smc: Use sysctl-specified types of buffers in new link group net/smc: Allow virtually contiguous sndbufs or RMBs for SMC-R net/smc: Extend SMC-R link group netlink attribute Documentation/networking/smc-sysctl.rst | 13 ++ include/net/netns/smc.h | 1 + include/uapi/linux/smc.h | 1 + net/smc/af_smc.c | 68 +++++++-- net/smc/smc_clc.c | 8 +- net/smc/smc_clc.h | 2 +- net/smc/smc_core.c | 246 +++++++++++++++++++++----------- net/smc/smc_core.h | 20 ++- net/smc/smc_ib.c | 44 +++++- net/smc/smc_ib.h | 2 + net/smc/smc_llc.c | 33 +++-- net/smc/smc_rx.c | 92 +++++++++--- net/smc/smc_sysctl.c | 11 ++ net/smc/smc_tx.c | 10 +- 14 files changed, 404 insertions(+), 147 deletions(-) Acked-by: Wenjia Zhang