From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 3/3] eventfd: add internal reference counting to fix
	notifier race conditions
Date: Mon, 22 Jun 2009 21:41:39 +0300
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Cc: Gregory Haskins <ghaskins@novell.com>, kvm@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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	Ingo Molnar <mingo@elte.hu>,
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To: Davide Libenzi <davidel@xmailserver.org>
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On Mon, Jun 22, 2009 at 11:03:22AM -0700, Davide Libenzi wrote:
> In your case of kernel-to-kernel scenario, why would you need eventfd at 
> all, if userspace role in that model is simply to create it?

That's not 100% true. We have a mode where userspace is the producer
and/or consumer (migration mode) and we switch between that and
direct kernel-to-kernel communication.