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=-16.4 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 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 69E9EC47096 for ; Thu, 3 Jun 2021 09:07:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47A29613AC for ; Thu, 3 Jun 2021 09:07:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229567AbhFCJJh (ORCPT ); Thu, 3 Jun 2021 05:09:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:52844 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbhFCJJg (ORCPT ); Thu, 3 Jun 2021 05:09:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CBF80613AD; Thu, 3 Jun 2021 09:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622711272; bh=tyTxLmRzGcLrgS5s1ZrV5gXEzztjA30ML1iCEHzJ9Ys=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t/rqjzqj4JsVvW4HTGMme6CBwV0/ZE4SynU6ck6KdisYT5/MNBHA2UjAfyxV6ceij FSnjsE66z2H0mzgwqGfxn6pI6kjUvd9NXANos5c0mrcQuoEN7yt09/12nTyorr5d7z jY2bVMlAXhsgoHya2sbDUmeDCmX2FIs2+mJVlHWmWOfufGwfUnwbHYLRNzifgwi+dS OdvukMKMRXhtBCsJxoEUhMTd8NonP5CeE+YZUCkQqTHuWRarmoaPS+9Z2Jy0JPWRZA GlRbFZqocJGyaAtGJWKgJlqxWo9/GCsyC2faCyXaz9icR9gaoadu1ucwkYLYGnSlnn 4RgCVPHJ1Cy6A== Date: Thu, 3 Jun 2021 12:07:48 +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 v2 3/3] IB/core: Obtain subnet_prefix from cache in IB devices Message-ID: References: <20210603065024.1051-1-anand.a.khoje@oracle.com> <20210603065024.1051-4-anand.a.khoje@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210603065024.1051-4-anand.a.khoje@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Thu, Jun 03, 2021 at 12:20:24PM +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. > > Fixes: fad61ad ("IB/core: Add subnet prefix to port info") > Signed-off-by: Anand Khoje > Signed-off-by: Haakon Bugge > --- > drivers/infiniband/core/cache.c | 7 ++++++- > drivers/infiniband/core/device.c | 9 +++++++++ > include/rdma/ib_cache.h | 6 ++++++ > include/rdma/ib_verbs.h | 6 ++++++ > 4 files changed, 27 insertions(+), 1 deletion(-) Can you please help me to understand how cache is updated? There are a lot of calls to ib_query_port() and I wonder how callers can get new GID after it was changed in already initialized cache. Thanks