From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756507Ab0F3OmY (ORCPT ); Wed, 30 Jun 2010 10:42:24 -0400 Received: from claw.goop.org ([74.207.240.146]:59967 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754237Ab0F3OmX (ORCPT ); Wed, 30 Jun 2010 10:42:23 -0400 Message-ID: <4C2B57CA.3070807@goop.org> Date: Wed, 30 Jun 2010 16:42:18 +0200 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 MIME-Version: 1.0 To: Jan Beulich CC: "mingo@elte.hu" , Stefano Stabellini , "tglx@linutronix.de" , Ky Srinivasan , "linux-kernel@vger.kernel.org" , "hpa@zytor.com" Subject: Re: [PATCH 2/4, v2] x86: enlightenment for ticket spin locks - Xen implementation References: <4C2A200F02000078000089E4@vpn.id2.novell.com> <4C2B1769.5090107@goop.org> <4C2B47190200007800008CB7@vpn.id2.novell.com> <4C2B4564.7030203@goop.org> <4C2B6AD60200007800008D90@vpn.id2.novell.com> <4C2B53D1.90101@goop.org> <4C2B72950200007800008DBA@vpn.id2.novell.com> In-Reply-To: <4C2B72950200007800008DBA@vpn.id2.novell.com> X-Enigmail-Version: 1.0.1 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/30/2010 04:36 PM, Jan Beulich wrote: > Are we perhaps talking about different things? I'm referring to > > static __always_inline void arch_spin_unlock(struct arch_spinlock *lock) > { > PVOP_VCALL1(pv_lock_ops.spin_unlock, lock); > } > > which is an indirect call which, as I understand it, gets replaced > with a direct one at runtime. But it remains to be a call (as opposed > to being a single inc instructions without CONFIG_PARAVIRT_SPINLOCKS). > Sorry, I'm referring to pv ticketlocks, not the current PARAVIRT_SPINLOCKS code. I agree the current PARAVIRT_SPINLOCKS implementation is suboptimal and needs to be replaced with something that's only called on the slow path. I just think the existing paravirt_ops mechanism can be used to implement it rather than adding something new. J