Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754820AbbHNCHY (ORCPT ); Thu, 13 Aug 2015 22:07:24 -0400 Received: from g1t5424.austin.hp.com ([15.216.225.54]:37197 "EHLO g1t5424.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751740AbbHNCHW (ORCPT ); Thu, 13 Aug 2015 22:07:22 -0400 Message-ID: <55CD4D54.2090008@hp.com> Date: Thu, 13 Aug 2015 22:07:16 -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: Peter Zijlstra CC: Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org, Scott J Norton , Douglas Hatch , Davidlohr Bueso Subject: Re: [PATCH v5 1/6] locking/pvqspinlock: Unconditional PV kick with _Q_SLOW_VAL References: <1439003881-17349-1-git-send-email-Waiman.Long@hp.com> <1439003881-17349-2-git-send-email-Waiman.Long@hp.com> <20150808060249.GT16853@twins.programming.kicks-ass.net> In-Reply-To: <20150808060249.GT16853@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1091 Lines: 29 On 08/08/2015 02:02 AM, Peter Zijlstra wrote: > On Fri, Aug 07, 2015 at 11:17:56PM -0400, Waiman Long wrote: >> If _Q_SLOW_VAL has been set, the vCPU state must have been vcpu_hashed. >> The extra check at the end of __pv_queued_spin_unlock() is unnecessary >> and so is removed. > This is half the patch it should be. > > Because if the load is not needed, then the store is not either, and > then there's the comments to update. Sorry for the late reply. That is true. Setting state to vcpu_hashed in pv_wait_head() isn't really necessary. I kept it there for consistency sake as the state may be set to vcpu_hashed in pv_kick_node(). We can certainly take that out. BTW, could you also review the other patches when you have time? I am coming to the LinuxCon/Plumbers next week. Hopefully, I can chat with you again. Cheers, Longman -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/