From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754859AbcFPVZs (ORCPT ); Thu, 16 Jun 2016 17:25:48 -0400 Received: from mail-by2on0111.outbound.protection.outlook.com ([207.46.100.111]:6167 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754466AbcFPVZp (ORCPT ); Thu, 16 Jun 2016 17:25:45 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=waiman.long@hpe.com; Message-ID: <5763194F.80109@hpe.com> Date: Thu, 16 Jun 2016 17:25:35 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Davidlohr Bueso CC: Peter Zijlstra , Ingo Molnar , , , , , , , Jason Low , Dave Chinner , Scott J Norton , Douglas Hatch Subject: Re: [RFC PATCH-tip v2 2/6] locking/rwsem: Stop active read lock ASAP References: <1465944489-43440-1-git-send-email-Waiman.Long@hpe.com> <1465944489-43440-3-git-send-email-Waiman.Long@hpe.com> <20160615172242.GQ30921@twins.programming.kicks-ass.net> <5761A9DE.6040702@hpe.com> <20160616021436.GA7765@linux-80c1.suse> In-Reply-To: <20160616021436.GA7765@linux-80c1.suse> Content-Type: text/plain; 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Since it is in the slowpath, one additional atomic op will just be a small part of the whole rwsem_down_read_failed() function. I doubt if the performance degradation, if any, can be even noticeable. Cheers, Longman