Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758262Ab2EAPlT (ORCPT ); Tue, 1 May 2012 11:41:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40879 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757131Ab2EAPlR (ORCPT ); Tue, 1 May 2012 11:41:17 -0400 Message-ID: <4FA003C8.7060004@redhat.com> Date: Tue, 01 May 2012 18:39:52 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Peter Zijlstra CC: "Nikunj A. Dadhania" , mingo@elte.hu, jeremy@goop.org, mtosatti@redhat.com, kvm@vger.kernel.org, x86@kernel.org, vatsa@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, hpa@zytor.com Subject: Re: [RFC PATCH v1 3/5] KVM: Add paravirt kvm_flush_tlb_others References: <20120427161727.27082.43096.stgit@abhimanyu> <20120427162401.27082.59387.stgit@abhimanyu> <4F9D32B4.8040002@redhat.com> <1335865176.13683.120.camel@twins> <4F9FBF38.2060903@redhat.com> <1335869827.13683.133.camel@twins> <4F9FD337.5010908@redhat.com> <1335884353.13683.144.camel@twins> <4FA001D8.6080801@redhat.com> <1335886587.13683.153.camel@twins> In-Reply-To: <1335886587.13683.153.camel@twins> 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 Content-Length: 1328 Lines: 35 On 05/01/2012 06:36 PM, Peter Zijlstra wrote: > On Tue, 2012-05-01 at 18:31 +0300, Avi Kivity wrote: > > On 05/01/2012 05:59 PM, Peter Zijlstra wrote: > > > On Tue, 2012-05-01 at 15:12 +0300, Avi Kivity wrote: > > > > local_irq_save() is a stronger version or rcu_read_lock() > > > > > > Not so, local_irq_save() doesn't at all stop regular RCU grace periods, > > > things like preemptible rcu can be driven from rcu_read_unlock(). > > > > > > Note that this is the reason call_rcu_sched() exists and is used in this > > > case. > > > > Ah, thanks for the correction. I'll read some more about the _sched > > variants. > > Basically: > > rcu_read_{,un}lock_sched() -- aka preempt_{en,dis}able() > call_rcu_sched() > synchronize_rcu_sched() -- aka synchronize_sched(); > > Define an RCU variant where each cpu has to have scheduled at least once > to complete a grace period. Which was the original rcu implementation, until it got replaced by preemptible rcu, yes? I guess that was the source of my confusion. -- error compiling committee.c: too many arguments to function -- 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/