Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755402AbdIFQU7 (ORCPT ); Wed, 6 Sep 2017 12:20:59 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:23734 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752462AbdIFQU5 (ORCPT ); Wed, 6 Sep 2017 12:20:57 -0400 Subject: Re: [PATCH net] rds: Fix incorrect statistics counting To: =?UTF-8?Q?H=c3=a5kon_Bugge?= Cc: "David S . Miller" , netdev@vger.kernel.org, OFED mailing list , rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org, Knut Omang References: <20170906152950.17766-1-Haakon.Bugge@oracle.com> <715EA84D-6ACA-45DE-9EA2-6122E11545E8@oracle.com> From: Santosh Shilimkar Organization: Oracle Corporation Message-ID: <6fb62a09-13b4-0cec-2864-40afdfc51d25@oracle.com> Date: Wed, 6 Sep 2017 09:21:01 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <715EA84D-6ACA-45DE-9EA2-6122E11545E8@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 598 Lines: 20 On 9/6/2017 9:12 AM, Håkon Bugge wrote: > [...] > > Hi Santosh, > > > Yes, I agree with accuracy of s_send_lock_queue_raced. But the main point is that the existing code counts some partial share of when it is _not_ raced. > > So, in the critical path, my patch adds one test_bit(), which hits the local CPU cache, if not raced. If raced, some other thread is in control, so I would not think the added cycles would make any big difference. > Cycles added for no good reason is the point. > I can send a v2 where the race tightening is removed if you like. > Yes please. Regards, Santosh