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=-16.2 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 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 17343C49361 for ; Thu, 17 Jun 2021 06:41:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2D9A60C40 for ; Thu, 17 Jun 2021 06:41:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229716AbhFQGoC (ORCPT ); Thu, 17 Jun 2021 02:44:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:52324 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbhFQGn7 (ORCPT ); Thu, 17 Jun 2021 02:43:59 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BF7D3610A1; Thu, 17 Jun 2021 06:41:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1623912112; bh=k22wDppAh/+MfBvxHK3lLfrhgV48Cp0+hy+NlhOezjo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=k08qDhZlti1TGwtsRZt2sGX5il6HZSEPQc9KEU9lcYZJ9epJmsJhpdQhHJo+8JEH8 z+uvVXOG6rQoPoalYEBq8a1AQBGwW+LtHW7etqnBNL7/j4hsMvJ+/o8WeqsxHMjh1r LoLKrExPTPT9OJWkitYeLYaZCCX3meQ69TMJ7Znqc0tM5loMkBaZGKTqg347zPV1Di m+ggFt9C8a2N2O+Vu6BQR+c2q8UtqJIU6tl3lpFSlys9YeSoNedn3zzesycIq24dpL jh/zQzUaBGBKVRPGLSEgwiOx0s75d+5KfrJphRDuHnDmmNuQz9ZAZjJ45s4pWnHvgg U9W90I8i+UCbQ== Date: Thu, 17 Jun 2021 09:41:47 +0300 From: Leon Romanovsky To: Anand Khoje Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, dledford@redhat.com, jgg@ziepe.ca, haakon.bugge@oracle.com Subject: Re: [PATCH v5 for-next 3/3] IB/core: Obtain subnet_prefix from cache in IB devices Message-ID: References: <20210616154509.1047-1-anand.a.khoje@oracle.com> <20210616154509.1047-4-anand.a.khoje@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210616154509.1047-4-anand.a.khoje@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Wed, Jun 16, 2021 at 09:15:09PM +0530, Anand Khoje wrote: > ib_query_port() calls device->ops.query_port() to get the port > attributes. The method of querying is device driver specific. > The same function calls device->ops.query_gid() to get the GID and > extract the subnet_prefix (gid_prefix). > > The GID and subnet_prefix are stored in a cache. But they do not get > read from the cache if the device is an Infiniband device. The > following change takes advantage of the cached subnet_prefix. > Testing with RDBMS has shown a significant improvement in performance > with this change. > > The function ib_cache_is_initialised() is introduced because > ib_query_port() gets called early in the stage when the cache is not > built while reading port immutable property. > > In that case, the default GID still gets read from HCA for IB link- > layer devices. > > In the situation of an event causing cache update, the subnet_prefix > will get retrieved from newly updated GID cache in ib_cache_update(), > so that we do not end up reading a stale value from cache via > ib_query_port(). > > Fixes: fad61ad ("IB/core: Add subnet prefix to port info") > Suggested-by: Leon Romanovsky > Suggested-by: Aru Kolappan > Signed-off-by: Anand Khoje > Signed-off-by: Haakon Bugge > --- > > v1 -> v2: > - Split the v1 patch in 3 patches as per Leon's suggestion. > > v2 -> v3: > - Added changes as per Mark Zhang's suggestion of clearing > flags in git_table_cleanup_one(). > v3 -> v4: > - Removed the enum ib_port_data_flags and 8 byte flags from > struct ib_port_data, and the set_bit()/clear_bit() API > used to update this flag as that was not necessary. > Done to keep the code simple. > - Added code to read subnet_prefix from updated GID cache in the > event of cache update. Prior to this change, ib_cache_update > was reading the value for subnet_prefix via ib_query_port(), > due to this patch, we ended up reading a stale cached value of > subnet_prefix. > v4 -> v5: > - Removed the code to reset cache_is_initialised bit from cleanup > as per Leon's suggestion. > - Removed ib_cache_is_initialised() function. > > --- > drivers/infiniband/core/cache.c | 14 ++++++++++++-- > drivers/infiniband/core/device.c | 9 +++++++++ > include/rdma/ib_verbs.h | 1 + > 3 files changed, 22 insertions(+), 2 deletions(-) > Thanks, Reviewed-by: Leon Romanovsky