From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: Re: [PATCH v2 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock Date: Thu, 4 Apr 2019 14:03:15 -0400 Message-ID: <6b5b03ae-d1f4-bfbb-5866-37046c8a47c8@redhat.com> References: <20190329152006.110370-1-alex.kogan@oracle.com> <20190329152006.110370-4-alex.kogan@oracle.com> <60a3a2d8-d222-73aa-2df1-64c9d3fa3241@redhat.com> <20190402094320.GM11158@hirez.programming.kicks-ass.net> <6AEDE4F2-306A-4DF9-9307-9E3517C68A2B@oracle.com> <20190403160112.GK4038@hirez.programming.kicks-ass.net> <20190404093859.GU4038@hirez.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190404093859.GU4038@hirez.programming.kicks-ass.net> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Peter Zijlstra , Juergen Gross Cc: Alex Kogan , linux@armlinux.org.uk, mingo@redhat.com, will.deacon@arm.com, arnd@arndb.de, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, steven.sistare@oracle.com, daniel.m.jordan@oracle.com, dave.dice@oracle.com, rahul.x.yadav@oracle.com List-Id: linux-arch.vger.kernel.org On 04/04/2019 05:38 AM, Peter Zijlstra wrote: > On Thu, Apr 04, 2019 at 07:05:24AM +0200, Juergen Gross wrote: > >> Without PARAVIRT_SPINLOCK this would be just an alternative() then? > That could maybe work yes. This is all early enough. Yes, alternative() should work as it is done before SMP boot. The slowpath should never be executed before SMP boot. Cheers, Longman From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:55198 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726418AbfDDSDU (ORCPT ); Thu, 4 Apr 2019 14:03:20 -0400 Subject: Re: [PATCH v2 3/5] locking/qspinlock: Introduce CNA into the slow path of qspinlock References: <20190329152006.110370-1-alex.kogan@oracle.com> <20190329152006.110370-4-alex.kogan@oracle.com> <60a3a2d8-d222-73aa-2df1-64c9d3fa3241@redhat.com> <20190402094320.GM11158@hirez.programming.kicks-ass.net> <6AEDE4F2-306A-4DF9-9307-9E3517C68A2B@oracle.com> <20190403160112.GK4038@hirez.programming.kicks-ass.net> <20190404093859.GU4038@hirez.programming.kicks-ass.net> From: Waiman Long Message-ID: <6b5b03ae-d1f4-bfbb-5866-37046c8a47c8@redhat.com> Date: Thu, 4 Apr 2019 14:03:15 -0400 MIME-Version: 1.0 In-Reply-To: <20190404093859.GU4038@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra , Juergen Gross Cc: Alex Kogan , linux@armlinux.org.uk, mingo@redhat.com, will.deacon@arm.com, arnd@arndb.de, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, steven.sistare@oracle.com, daniel.m.jordan@oracle.com, dave.dice@oracle.com, rahul.x.yadav@oracle.com Message-ID: <20190404180315.0n3ap9rqkW5XFp8rjaHKdVvg1_-WrZylvDbL8I7FWlw@z> On 04/04/2019 05:38 AM, Peter Zijlstra wrote: > On Thu, Apr 04, 2019 at 07:05:24AM +0200, Juergen Gross wrote: > >> Without PARAVIRT_SPINLOCK this would be just an alternative() then? > That could maybe work yes. This is all early enough. Yes, alternative() should work as it is done before SMP boot. The slowpath should never be executed before SMP boot. Cheers, Longman