From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC PATCH v1 3/5] KVM: Add paravirt kvm_flush_tlb_others
Date: Tue, 01 May 2012 16:59:13 +0200
Message-ID: <1335884353.13683.144.camel@twins>
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>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7BIT
Cc: "Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>, 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
To: Avi Kivity <avi@redhat.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <4F9FD337.5010908@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: kvm.vger.kernel.org

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.