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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, 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 11C76C31E45 for ; Thu, 13 Jun 2019 15:29:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DAE6D206BB for ; Thu, 13 Jun 2019 15:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727725AbfFMP26 (ORCPT ); Thu, 13 Jun 2019 11:28:58 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40134 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727315AbfFMP25 (ORCPT ); Thu, 13 Jun 2019 11:28:57 -0400 Received: by mail-pl1-f194.google.com with SMTP id a93so8309499pla.7; Thu, 13 Jun 2019 08:28:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=yUJJ8iqcvuJ3BPVcgtI/PQYUXpHj8gT005mFggb92XQ=; b=PF3GNfhjtwVYJdzQBH96+/hxI1EhFG/gMHdHTnBfDvIBuBxpMxbseSn/0HkOCDhkDm JSk0oxYKaKsLKxUgd/3HTPaasTCgDkhU1AgxMIpGAqHtTI1x6GuFenwI1rtMu4wrFYp/ e5tTP4UbcYIRq40/KTzyDLttdXHgGsgyzzFi7PohP5+DXHBAx4sAVAfO5aK9Vgtjlugq rw9WKZ81kBEe1eNDOUBlKPLA2Y4bdDZHVp//CTmMiyCYjDqBTJm2TMbYFnoJHLOGue/N kDa+luB3kqyZ1FLAQuPK3zKa9DHiO+tTFs7XSnJp0cN6/6fkNcXhQ0GUPRU1dfGn5ZZa MvOA== X-Gm-Message-State: APjAAAWG9w8EuKdzM4hgqqU7IgAfyX2gevBs5KTJHv8nYm1GErXxf4dw oZFuLsiljcNikXenlRhCP+vAZu/B X-Google-Smtp-Source: APXvYqw8UXQ2qB/hmtqwZrw/7powAQsjJBiHMBd48yk7lWGltCuWgtRv5qqnMMohLJcBcgyuOnD9Iw== X-Received: by 2002:a17:902:bd94:: with SMTP id q20mr2154027pls.307.1560439735599; Thu, 13 Jun 2019 08:28:55 -0700 (PDT) Received: from desktop-bart.svl.corp.google.com ([2620:15c:2cd:202:4308:52a3:24b6:2c60]) by smtp.gmail.com with ESMTPSA id r3sm164908pgp.51.2019.06.13.08.28.54 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jun 2019 08:28:54 -0700 (PDT) Subject: Re: [PATCH v2] RDMA/cma: Make CM response timeout and # CM retries configurable To: Doug Ledford , =?UTF-8?Q?H=c3=a5kon_Bugge?= , Jason Gunthorpe , Leon Romanovsky , Parav Pandit , Steve Wise Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190226075722.1692315-1-haakon.bugge@oracle.com> <174ccd37a9ffa05d0c7c03fe80ff7170a9270824.camel@redhat.com> From: Bart Van Assche Message-ID: <2c114313-01fe-6d4d-5134-592d1a7b829b@acm.org> Date: Thu, 13 Jun 2019 08:28:53 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <174ccd37a9ffa05d0c7c03fe80ff7170a9270824.camel@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/13/19 7:25 AM, Doug Ledford wrote: > So, to revive this patch, what I'd like to see is some attempt to > actually quantify a reasonable timeout for the default backlog depth, > then the patch should actually change the default to that reasonable > timeout, and then put in the ability to adjust the timeout with some > sort of doc guidance on how to calculate a reasonable timeout based on > configured backlog depth. How about following the approach of the SRP initiator driver? It derives the CM timeout from the subnet manager timeout. The assumption behind this is that in large networks the subnet manager timeout has to be set higher than its default to make communication work. See also srp_get_subnet_timeout(). Bart.